marine weather course noaa national weather service baltimore/washington forecast office
TRANSCRIPT
Marine Weather Course
NOAA National Weather ServiceNOAA National Weather Service
Baltimore/Washington Forecast OfficeBaltimore/Washington Forecast Office
Part I Outline
• National Weather Service IntroductionNational Weather Service Introduction
• Baltimore/Washington Forecast Office Baltimore/Washington Forecast Office Operations and Marine AreaOperations and Marine Area
• Key Marine Products and HazardsKey Marine Products and Hazards
• Marine Observation and Forecast InformationMarine Observation and Forecast Information
• Marine SafetyMarine Safety
• Marine ReportingMarine Reporting
NWS Service Delivery Facilities
WFO Area of Responsibility
• MarylandMaryland• 13 Counties13 Counties• City of BaltimoreCity of Baltimore
• West VirginiaWest Virginia• 8 Counties8 Counties
• VirginiaVirginia• 22 Counties22 Counties• 11 independent 11 independent
citiescities
• District of ColumbiaDistrict of Columbia• River BasinsRiver Basins
• PotomacPotomac• ShenandoahShenandoah• RappahannockRappahannock
• Marine AreaMarine Area• Tidal Potomac Tidal Potomac
RiverRiver• MD Chesapeake MD Chesapeake
BayBay
• MarylandMaryland• 13 Counties13 Counties• City of BaltimoreCity of Baltimore
• West VirginiaWest Virginia• 8 Counties8 Counties
• VirginiaVirginia• 22 Counties22 Counties• 11 independent 11 independent
citiescities
• District of ColumbiaDistrict of Columbia• River BasinsRiver Basins
• PotomacPotomac• ShenandoahShenandoah• RappahannockRappahannock
• Marine AreaMarine Area• Tidal Potomac Tidal Potomac
RiverRiver• MD Chesapeake MD Chesapeake
BayBay
Region is prone to all weather hazardsRegion is prone to all weather hazardsRegion is prone to all weather hazardsRegion is prone to all weather hazards
Approximately 27,000 square miles Approximately 27,000 square miles Serving ~9 Million PeopleServing ~9 Million People
Approximately 27,000 square miles Approximately 27,000 square miles Serving ~9 Million PeopleServing ~9 Million People
Operations & Services
• ConvectiveConvective- Tornado & Severe Thunderstorm- Tornado & Severe Thunderstorm
• Tropical SystemsTropical Systems- Hurricanes & Tropical Storms- Hurricanes & Tropical Storms
• Non-PrecipitableNon-Precipitable- Heat Waves- Heat Waves- High Wind- High Wind- Wind Chill/Excessive Cold- Wind Chill/Excessive Cold
• HydrologicalHydrological- Flash Floods- Flash Floods- River Floods- River Floods- Small Stream & Tributaries- Small Stream & Tributaries
• Winter StormsWinter Storms• Coastal FloodingCoastal Flooding• Wildfire (Red Flag)Wildfire (Red Flag)
Spruce Knob, Pendleton County, WV
Elevation 4,861 feet
Operations & Services (cont.)
• ForecastsForecasts- Public- Public
- Marine- Marine
- Aviation- Aviation
- Fire Weather- Fire Weather
- River- River
• Support ServicesSupport Services- Homeland Security- Homeland Security
• Data CollectionData Collection- Climate- Climate
- Cooperative - Cooperative ObserversObservers
Marine Area
Key Marine Products
• Coastal Waters Forecast Coastal Waters Forecast (CWFLWX)(CWFLWX)
• Special Marine Warnings Special Marine Warnings (SMWLWX)(SMWLWX)
• Marine Weather Statements Marine Weather Statements (MWSLWX)(MWSLWX)
• Nowcasts (NOWLWX)Nowcasts (NOWLWX)
Coastal Waters Forecast
• Issued a minimum of 4 times / dayIssued a minimum of 4 times / day• Amendments issued as necessaryAmendments issued as necessary• Each CWF goes out 5 days, with each period covering 12 Each CWF goes out 5 days, with each period covering 12
hourshours• Used by small pleasure boaters to large commercial Used by small pleasure boaters to large commercial
transport ships. transport ships.
Coastal Waters Forecast
Elements:Elements:
• Synopsis – Short, conciseSynopsis – Short, concise
• Headlines of long duration hazards: Advisories, Watches, Headlines of long duration hazards: Advisories, Watches, WarningsWarnings
• Wind – from 8 compass points, in knots (kt)Wind – from 8 compass points, in knots (kt)
• Waves – wave heights, in feet (ft)Waves – wave heights, in feet (ft)
• Weather – thunderstorms, rain, snow and fog (significant Weather – thunderstorms, rain, snow and fog (significant visibility reduction) visibility reduction)
Long Duration Hazards
Small Craft Advisory: (Tidal Potomac and Small Craft Advisory: (Tidal Potomac and Chesapeake Bay) -- the following conditions are Chesapeake Bay) -- the following conditions are occurring or expected to begin within the first 3 occurring or expected to begin within the first 3 forecast periods:forecast periods:
• Sustained winds 18-33 ktSustained winds 18-33 kt
• Frequent gusts 18-33 ktFrequent gusts 18-33 kt
(frequent refers to lasting > 2 hours)(frequent refers to lasting > 2 hours)
• Waves 4 ftWaves 4 ft
Long Duration Hazards
Gale Warning: (Tidal Potomac and Chesapeake Gale Warning: (Tidal Potomac and Chesapeake Bay) -- the following conditions are occurring or Bay) -- the following conditions are occurring or expected to begin within the first 3 forecast expected to begin within the first 3 forecast periods:periods:
• Sustained winds 34-47 ktSustained winds 34-47 kt
• Frequent gusts 34-47 ktFrequent gusts 34-47 kt
Long Duration Hazards
Storm Warning: (Tidal Potomac and Chesapeake Storm Warning: (Tidal Potomac and Chesapeake Bay) -- the following conditions are occurring or Bay) -- the following conditions are occurring or expected to begin within the first 3 forecast expected to begin within the first 3 forecast periods:periods:
• Sustained winds 48-63 ktSustained winds 48-63 kt
• Frequent gusts 48-63 ktFrequent gusts 48-63 kt
Long Duration Hazards
Hurricane Force Wind Warning: (Tidal Potomac and Hurricane Force Wind Warning: (Tidal Potomac and Chesapeake Bay) -- the following conditions are occurring Chesapeake Bay) -- the following conditions are occurring or expected to begin within the first 3 forecast periods:or expected to begin within the first 3 forecast periods:
• Sustained winds 64 kt or greaterSustained winds 64 kt or greater
• Frequent gusts 64 kt or greaterFrequent gusts 64 kt or greater
• Not associated with a tropical systemNot associated with a tropical system
Tropical Hazards
Tropical Watches/WarningsTropical Watches/Warnings
• Initiated by National Hurricane Initiated by National Hurricane Center in MiamiCenter in Miami
• nhc.noaa.govnhc.noaa.gov
• Tropical Storm (sustained winds Tropical Storm (sustained winds 34 to 63 kt / 39 to 73 mph)34 to 63 kt / 39 to 73 mph)
• Hurricane (sustained winds Hurricane (sustained winds >> 64 64 kt / kt / >> 74 mph) 74 mph)
Isabel, 2003
Convective Hazards
Severe Local Storm Severe Local Storm Watches Watches
• Initiated by Storm Initiated by Storm Prediction Center in Prediction Center in Norman, OKNorman, OK
• spc.noaa.govspc.noaa.gov• Tornado WatchTornado Watch• Severe Thunderstorm Severe Thunderstorm
WatchWatch
Coastal Waters Forecast
ANZ535-536-231930- ANZ535-536-231930- /X.EXT.KLWX.SC.Y.0037.051023T1200Z-051023T2200Z/ /X.EXT.KLWX.SC.Y.0037.051023T1200Z-051023T2200Z/ TIDAL POTOMAC FROM KEY BRIDGE TO INDIAN HEAD- TIDAL POTOMAC FROM KEY BRIDGE TO INDIAN HEAD- TIDAL POTOMAC FROM INDIAN HEAD TO COBB ISLAND- TIDAL POTOMAC FROM INDIAN HEAD TO COBB ISLAND- 337 AM EDT SUN OCT 23 2005 337 AM EDT SUN OCT 23 2005
...SMALL CRAFT ADVISORY NOW IN EFFECT FROM 6 AM EDT THIS MORNING THROUGH THIS ...SMALL CRAFT ADVISORY NOW IN EFFECT FROM 6 AM EDT THIS MORNING THROUGH THIS AFTERNOON... AFTERNOON...
.TODAY...NW WINDS 15 TO 20 KT. WAVES 1 TO 2 FT. .TODAY...NW WINDS 15 TO 20 KT. WAVES 1 TO 2 FT.
.TONIGHT...E WINDS 5 TO 10 KT. WAVES 1 FT OR LESS. .TONIGHT...E WINDS 5 TO 10 KT. WAVES 1 FT OR LESS.
.MON...NE WINDS 5 TO 10 KT. WAVES 1 FT OR LESS. A CHANCE OF .MON...NE WINDS 5 TO 10 KT. WAVES 1 FT OR LESS. A CHANCE OF SHOWERS. SHOWERS. .MON NIGHT...N WINDS 10 TO 15 KT. WAVES 1 FT. A CHANCE OF SHOWERS. .MON NIGHT...N WINDS 10 TO 15 KT. WAVES 1 FT. A CHANCE OF SHOWERS. .TUE...NW WINDS 15 TO 20 KT. WAVES 1 TO 2 FT. .TUE...NW WINDS 15 TO 20 KT. WAVES 1 TO 2 FT. .TUE NIGHT...NW WINDS 10 TO 15 KT. WAVES 1 FT. .TUE NIGHT...NW WINDS 10 TO 15 KT. WAVES 1 FT. .WED...W WINDS 10 TO 15 KT. WAVES 1 FT..WED...W WINDS 10 TO 15 KT. WAVES 1 FT..THU...NW WINDS 5 TO 10 KT. WAVES 1 FT OR LESS. .THU...NW WINDS 5 TO 10 KT. WAVES 1 FT OR LESS.
$$ $$
Special Marine Warnings
Issued for potentially hazardous over-water weather Issued for potentially hazardous over-water weather conditions of short duration (2 hours or less) and conditions of short duration (2 hours or less) and producing winds speeds or gusts 34 kt or greater producing winds speeds or gusts 34 kt or greater not covered by existing longer fused products.not covered by existing longer fused products.
• Gusty showers/thunderstorms with winds 34 kt or Gusty showers/thunderstorms with winds 34 kt or greatergreater
• WaterspoutsWaterspouts
Special Marine Warnings
BULLETIN - IMMEDIATE BROADCAST REQUESTED BULLETIN - IMMEDIATE BROADCAST REQUESTED SPECIAL MARINE WARNING SPECIAL MARINE WARNING NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 621 PM EST SUN NOV 6 2005 621 PM EST SUN NOV 6 2005
THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A
** SPECIAL MARINE WARNING FOR... SPECIAL MARINE WARNING FOR... CHESAPEAKE BAY NORTH OF POOLES ISLAND, MD... CHESAPEAKE BAY NORTH OF POOLES ISLAND, MD... CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT, MD... CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT, MD...
* * UNTIL 745 PM EST UNTIL 745 PM EST
* * AT 621 PM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A CLUSTER OF GUSTY SHOWERS ABOUT 20 AT 621 PM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A CLUSTER OF GUSTY SHOWERS ABOUT 20 MILES WEST OF BALTIMORE HARBOR.... MOVING EAST AT 45 MPH. IN ADDITION...GUSTY WINDS ASSOCIATED WITH A MILES WEST OF BALTIMORE HARBOR.... MOVING EAST AT 45 MPH. IN ADDITION...GUSTY WINDS ASSOCIATED WITH A COLD FRONT WILL PASS OVER THE WATERS JUST AFTER THE SHOWERS PASS THROUGH AFTER 7 PM. COLD FRONT WILL PASS OVER THE WATERS JUST AFTER THE SHOWERS PASS THROUGH AFTER 7 PM.
** THIS ACTIVITY WILL AFFECT THE WATERS AFFECT... THIS ACTIVITY WILL AFFECT THE WATERS AFFECT... BALTIMORE INNER HARBOR... BALTIMORE INNER HARBOR... HART MILLER ISLAND... HART MILLER ISLAND... POOLES ISLAND... POOLES ISLAND... TOLCHESTER BEACH... TOLCHESTER BEACH...
MARINERS CAN EXPECT WIND GUSTS OVER 35 KT...HIGH WAVES...LIGHTNING AND HEAVY DOWNPOURS. BOATERS SHOULD MARINERS CAN EXPECT WIND GUSTS OVER 35 KT...HIGH WAVES...LIGHTNING AND HEAVY DOWNPOURS. BOATERS SHOULD SEEK SAFE HARBOR IMMEDIATELY UNTIL THIS STORM PASSES. SEEK SAFE HARBOR IMMEDIATELY UNTIL THIS STORM PASSES.
LAT...LON 3937 7700 3919 7693 3900 7604 3969 7569 LAT...LON 3937 7700 3919 7693 3900 7604 3969 7569
$$ $$
Marine Weather Statements
• Update/Continue Special Marine WarningUpdate/Continue Special Marine Warning
• Expire/Cancel Special Marine WarningExpire/Cancel Special Marine Warning
• Issued for long term sub-severe hazards lasting for Issued for long term sub-severe hazards lasting for longer than 2 hours that will impact marine longer than 2 hours that will impact marine operationsoperations
Marine Weather Statements
MARINE WEATHER STATEMENTMARINE WEATHER STATEMENTNATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1045 AM EDT SUN AUG 7 20051045 AM EDT SUN AUG 7 2005
ANZ531-071545- ANZ531-071545- /O.CON.KLWX.MA.W.0106.000000T0000Z-050807T1545Z/ /O.CON.KLWX.MA.W.0106.000000T0000Z-050807T1545Z/ 1045 AM EDT SUN AUG 7 2005 1045 AM EDT SUN AUG 7 2005
...A SPECIAL MARINE WARNING CONTINUES UNTIL 1145 AM EDT... ...A SPECIAL MARINE WARNING CONTINUES UNTIL 1145 AM EDT...
FOR THE FOLLOWING AREA... FOR THE FOLLOWING AREA... CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT, MD CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT, MD
AT 1044 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO INDICATE A LINE OF AT 1044 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO INDICATE A LINE OF THUNDERSTORMS...PRODUCING STRONG WINDS OVER 35 KNOTS FROM CEDAR BEACH TO 9 MILES SOUTHWEST OF THUNDERSTORMS...PRODUCING STRONG WINDS OVER 35 KNOTS FROM CEDAR BEACH TO 9 MILES SOUTHWEST OF ROCK HALL...OR FROM 7 MILES WEST OF POOLES ISLAND TO 3 MILES NORTH OF SANDY POINT...MOVING NORTHEAST ROCK HALL...OR FROM 7 MILES WEST OF POOLES ISLAND TO 3 MILES NORTH OF SANDY POINT...MOVING NORTHEAST AT 15 MPH. AT 15 MPH.
OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO HART MILLER ISLAND...CARROLL OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO HART MILLER ISLAND...CARROLL ISLAND...TOLCHESTER BEACH AND ROCKY POINT. ISLAND...TOLCHESTER BEACH AND ROCKY POINT.
MARINERS CAN EXPECT GUSTY WINDS...HIGH WAVES...REDUCED VISIBILITIES...DANGEROUS LIGHTNING...AND HEAVY RAINS. MARINERS CAN EXPECT GUSTY WINDS...HIGH WAVES...REDUCED VISIBILITIES...DANGEROUS LIGHTNING...AND HEAVY RAINS. BOATERS SHOULD SEEK SAFE HARBOR IMMEDIATELY...UNTIL THIS STORM PASSES. BOATERS SHOULD SEEK SAFE HARBOR IMMEDIATELY...UNTIL THIS STORM PASSES.
FREQUENT LIGHTNING IS OCCURRING WITH THIS STORM. IF CAUGHT ON THE OPEN WATER STAY BELOW DECK IF FREQUENT LIGHTNING IS OCCURRING WITH THIS STORM. IF CAUGHT ON THE OPEN WATER STAY BELOW DECK IF POSSIBLE...KEEP AWAY FROM UNGROUNDED METAL OBJECTS. POSSIBLE...KEEP AWAY FROM UNGROUNDED METAL OBJECTS.
$$ $$
Nowcasts
• Issued for short term non-severe hazards but Issued for short term non-severe hazards but potentially dangerous conditions, such as with winds potentially dangerous conditions, such as with winds to 33 kt lasting for 2 hours or less. to 33 kt lasting for 2 hours or less.
• Sometimes combined with land zones, but oftentimes Sometimes combined with land zones, but oftentimes appearing only as a marine Nowcast. appearing only as a marine Nowcast.
Nowcasts
SHORT TERM FORECAST SHORT TERM FORECAST NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 804 AM EDT FRI OCT 21 2005 804 AM EDT FRI OCT 21 2005
ANZ530>537-DCZ001-MDZ005>007-009>011-013-014-016>018-VAZ041-042- 052>057-211330- ANZ530>537-DCZ001-MDZ005>007-009>011-013-014-016>018-VAZ041-042- 052>057-211330- ANNE ARUNDEL MD-ARLINGTON/FALLS CHURCH/ALEXANDRIA VA-CALVERT MD-CARROLL MD-CHARLES MD-DISTRICT OF ANNE ARUNDEL MD-ARLINGTON/FALLS CHURCH/ALEXANDRIA VA-CALVERT MD-CARROLL MD-CHARLES MD-DISTRICT OF COLUMBIA DC-FAIRFAX VA-FAUQUIER VA-HARFORD MD-HOWARD MD-KING GEORGE VA-LOUDOUN VA-MONTGOMERY MD-COLUMBIA DC-FAIRFAX VA-FAUQUIER VA-HARFORD MD-HOWARD MD-KING GEORGE VA-LOUDOUN VA-MONTGOMERY MD-NORTHERN BALTIMORE MD-PRINCE GEORGES MD-PRINCE WILLIAM/MANASSAS/MANASSAS PARK VA-SOUTHERN NORTHERN BALTIMORE MD-PRINCE GEORGES MD-PRINCE WILLIAM/MANASSAS/MANASSAS PARK VA-SOUTHERN BALTIMORE MD-SPOTSYLVANIA VA-ST.MARYS MD-STAFFORD VA- BALTIMORE MD-SPOTSYLVANIA VA-ST.MARYS MD-STAFFORD VA- CHESAPEAKE BAY FROM DRUM POINT, MD TO SMITH POINT, VA- CHESAPEAKE BAY FROM DRUM POINT, MD TO SMITH POINT, VA- CHESAPEAKE BAY FROM NORTH BEACH TO DRUM POINT, MD- CHESAPEAKE BAY FROM NORTH BEACH TO DRUM POINT, MD- CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT, MD- CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT, MD- CHESAPEAKE BAY FROM SANDY POINT TO NORTH BEACH, MD- CHESAPEAKE BAY FROM SANDY POINT TO NORTH BEACH, MD- CHESAPEAKE BAY NORTH OF POOLES ISLAND, MD- CHESAPEAKE BAY NORTH OF POOLES ISLAND, MD- TIDAL POTOMAC FROM COBB ISLAND, MD TO SMITH POINT, VA- TIDAL POTOMAC FROM COBB ISLAND, MD TO SMITH POINT, VA- TIDAL POTOMAC FROM INDIAN HEAD TO COBB ISLAND, MD- TIDAL POTOMAC FROM INDIAN HEAD TO COBB ISLAND, MD- TIDAL POTOMAC FROM KEY BRIDGE TO INDIAN HEAD, MD- TIDAL POTOMAC FROM KEY BRIDGE TO INDIAN HEAD, MD- 804 AM EDT FRI OCT 21 2005804 AM EDT FRI OCT 21 2005
.NOW....NOW... ...HEAVY RAIN AND THUNDERSTORMS AFFECTING THE MORNING COMMUTE......HEAVY RAIN AND THUNDERSTORMS AFFECTING THE MORNING COMMUTE... AT 804 AM EDT...DOPPLER RADAR INDICATED A LINE OF HEAVY RAIN WITH EMBEDDED THUNDERSTORMS...LOCATED FROM AT 804 AM EDT...DOPPLER RADAR INDICATED A LINE OF HEAVY RAIN WITH EMBEDDED THUNDERSTORMS...LOCATED FROM
JUST WEST OF BALTIMORE TO JUST WEST OF WASHINGTON DC AND FURTHER TO THE SOUTH. THIS ACTIVITY WAS JUST WEST OF BALTIMORE TO JUST WEST OF WASHINGTON DC AND FURTHER TO THE SOUTH. THIS ACTIVITY WAS MOVING EAST AT 25 MPH. MOVING EAST AT 25 MPH.
MORNING COMMUTERS SHOULD EXPECT TO ENCOUNTER BRIEF HEAVY RAIN...GUSTY WINDS UP TO 30 MPH...AS WELL AS MORNING COMMUTERS SHOULD EXPECT TO ENCOUNTER BRIEF HEAVY RAIN...GUSTY WINDS UP TO 30 MPH...AS WELL AS LIGHTNING. SOME OTHER COMMUNITIES THAT WILL SEE THIS ACTIVITY THROUGH 930 AM INCLUDE LAUREL LIGHTNING. SOME OTHER COMMUNITIES THAT WILL SEE THIS ACTIVITY THROUGH 930 AM INCLUDE LAUREL BROOK...SCARFF...BELLEVIEW...WOODBRIDGE...FALLSTON. BROOK...SCARFF...BELLEVIEW...WOODBRIDGE...FALLSTON.
THE TIDAL POTOMAC AND CHESAPEAKE BAY COASTAL WATERS WILL ALSO EXPERIENCE THIS ACTIVITY AFTER 830 AM. THE TIDAL POTOMAC AND CHESAPEAKE BAY COASTAL WATERS WILL ALSO EXPERIENCE THIS ACTIVITY AFTER 830 AM. MARINERS SHOULD ANTICIPATE THE GUSTY WINDS AND REDUCED VISIBILITIES. MARINERS SHOULD ANTICIPATE THE GUSTY WINDS AND REDUCED VISIBILITIES.
$$ $$
Marine Product RecapWhat’s Issued for the Waters?
Coastal Waters ForecastCoastal Waters Forecast Issued four times dailyIssued four times daily(4 AM, 11 AM, 4 PM, 11 PM)(4 AM, 11 AM, 4 PM, 11 PM)
•5 Day forecast5 Day forecast
Winds/Waves/Precipitation Winds/Waves/Precipitation (Visibility)(Visibility)
NOWCASTNOWCAST Non-Routine, 2-3 hour durationNon-Routine, 2-3 hour duration •Issued for sub-warning Issued for sub-warning criteria weather:criteria weather:
Mainly precipitation trendsMainly precipitation trends
Marine Weather StatementMarine Weather Statement Non-Routine, 2+ hours durationNon-Routine, 2+ hours duration •Update/Continue Special Update/Continue Special Marine WarningMarine Warning
•Expire/Cancel Special Expire/Cancel Special Marine WarningMarine Warning
•Issued for long term sub-Issued for long term sub-severe hazards lasting for severe hazards lasting for longer than 2 hours that will longer than 2 hours that will impact marine operationsimpact marine operations
Special Marine WarningSpecial Marine Warning Non-Routine, 2 hours or lessNon-Routine, 2 hours or less •Potentially hazardous Potentially hazardous weatherweather
•Showers/thunderstorms Showers/thunderstorms with winds 34 kt or greaterwith winds 34 kt or greater
Waterspouts, or large hailWaterspouts, or large hail
Sudden wind shiftSudden wind shift
NWS Homepage
• weather.gov/washington weather.gov/washington
• weather.gov/baltimoreweather.gov/baltimore
• Hazards highlighted on Hazards highlighted on front pagefront page
• Use “point and click” to Use “point and click” to view forecasts and view forecasts and specific hazard specific hazard informationinformation
Coastal Waters Forecast
• Coastal Waters ForecastCoastal Waters Forecast
• Headlines for long fused Headlines for long fused hazards listed at the top hazards listed at the top of the page of the page
• Headlines also Headlines also highlighted at the top of highlighted at the top of Coastal Waters Forecast Coastal Waters Forecast (Small Craft Advisory, (Small Craft Advisory, Gale Warning, etc)Gale Warning, etc)
Hazardous Weather Outlook
Hazardous Weather Outlook
• Alerts public to Alerts public to potential hazards and potential hazards and their impacttheir impact
• Potential hazards over Potential hazards over the next 7 days the next 7 days
• Marine hazardsMarine hazards
• Coastal hazardsCoastal hazards
Marine Weather Message
National Digital Forecast Database
• Graphical depiction of NWS Graphical depiction of NWS forecast elements through 7 daysforecast elements through 7 days– TemperatureTemperature– WeatherWeather– Sky CoverSky Cover– Many moreMany more
• Program specific sectors Program specific sectors – PublicPublic– MarineMarine– TropicalTropical– Fire WeatherFire Weather
• Zoom capability to the WFO level Zoom capability to the WFO level
National Digital Forecast Database
• Zoomed into the Tidal Zoomed into the Tidal Potomac and Potomac and Chesapeake BayChesapeake Bay
• Marine specific Marine specific elements highlightedelements highlighted– WindsWinds
– WavesWaves
– WeatherWeather
– HazardsHazards
www.weather.gov/forecasts/graphical
Hydrometeorological Prediction Center
• http://http://www.hpc.ncep.noaa.gov/www.hpc.ncep.noaa.gov/
• Current Weather Maps and Current Weather Maps and AnalysesAnalyses
• Surface Pressure ChartsSurface Pressure Charts
• Forecast Maps of Surface Forecast Maps of Surface FeaturesFeatures
Current Surface Map
• Isobars (lines of equal Isobars (lines of equal barometric pressure)barometric pressure)
• Low PressureLow Pressure
• High PressureHigh Pressure
• FrontsFronts
• TroughsTroughs
• Updated every few Updated every few hourshours
Current Radar
• Accessible through Accessible through HPC site as a larger HPC site as a larger regional loop ORregional loop OR
• Local radar viewed at Local radar viewed at Baltimore/Washington Baltimore/Washington sitesite
• Detects rain, snow, Detects rain, snow, thunderstormsthunderstorms
Current Marine Observations
• National Data Buoy Center National Data Buoy Center (NDBC)(NDBC)
• http://www.ndbc.noaa.gov/http://www.ndbc.noaa.gov/
• Contains NOAA/NWS Contains NOAA/NWS owned observation owned observation platformsplatforms
Current Marine Observations
• Chesapeake Bay Chesapeake Bay Interpretive Buoy Interpretive Buoy System (CBIBS)System (CBIBS)
• NOAA owned/fundedNOAA owned/funded
• Includes buoys which Includes buoys which are placed along the are placed along the historic John Smith historic John Smith TrailTrail
Current Marine Observations
• NOAA Tides and NOAA Tides and Currents (includes Currents (includes PORTS)PORTS)
• http://http://tidesandcurrents.noaa.gtidesandcurrents.noaa.gov/ov/
• More wind obsMore wind obs• Water level obsWater level obs• Short term wind/water Short term wind/water
level forecastslevel forecasts
NOAA Tides and Currents
• PORTS – Physical PORTS – Physical Oceanographic Real Oceanographic Real Time SystemTime System
• Graph gives overview Graph gives overview of past and current…of past and current…– Water levelsWater levels
– WindsWinds
– PressurePressure
– TemperatureTemperature
NOAA Tides and Currents
• High resolution modelsHigh resolution models
• Forecast of winds Forecast of winds (sustained) through 24 (sustained) through 24 hourshours
• Forecast of water levels Forecast of water levels through 24 hoursthrough 24 hours
• WFO Baltimore-Washington WFO Baltimore-Washington forecasts significant wave forecasts significant wave heights in the local Coastal heights in the local Coastal Waters Forecast (CWF) Waters Forecast (CWF) product.product.
• Significant wave heights are Significant wave heights are the average heights (trough to the average heights (trough to crest) of the one-third highest crest) of the one-third highest waves.waves.
• For simplicity, significant wave For simplicity, significant wave heights are termed waves in heights are termed waves in the WFO Baltimore-the WFO Baltimore-Washington CWF.Washington CWF.
Wind-Wave Correlations
• NOAA Weather Radio (NWR)NOAA Weather Radio (NWR)– Tone Alarm (SMW) within a minute of issuanceTone Alarm (SMW) within a minute of issuance
– All marine products are broadcast on NWRAll marine products are broadcast on NWR
Marine Hazard DisseminationHow Do We Convey the Message Today?
• Website (weather.gov/baltimore or Website (weather.gov/baltimore or weather.gov/washignton)weather.gov/washignton)– Colorful maps on website, click to see textColorful maps on website, click to see text
– http:/mobile.srh.noaa.gov (http-wireless)http:/mobile.srh.noaa.gov (http-wireless)• Recorded Forecast (CWF only)Recorded Forecast (CWF only)
– (703) 996-2200 (menu system)(703) 996-2200 (menu system)• Third parties (USCG) retransmitThird parties (USCG) retransmit
Marine Safety
Before going out onto the water…BE PREPARED!! Before going out onto the water…BE PREPARED!! Check the latest weather forecasts. Sources Check the latest weather forecasts. Sources include:include:
• NOAA Weather RadioNOAA Weather Radio
• Television Media – The Weather Channel or Local Television Media – The Weather Channel or Local TV Stations TV Stations
• Internet, including our website at:Internet, including our website at:WEATHER.GOV/WASHINGTONWEATHER.GOV/WASHINGTON
WEATHER.GOV/BALTIMOREWEATHER.GOV/BALTIMORE
Marine Safety
While on the water…STAY ALERT!! Have a NOAA While on the water…STAY ALERT!! Have a NOAA Weather Radio in your boat and continue to Weather Radio in your boat and continue to monitor the latest forecasts. monitor the latest forecasts.
• Pay attention to changes in marine forecastsPay attention to changes in marine forecasts
• Heed any issued advisories and warnings issuedHeed any issued advisories and warnings issued
• React appropriately to observed changes of React appropriately to observed changes of marine conditionsmarine conditions
Marine Safety
REMAIN ALERT for fast REMAIN ALERT for fast developing / approaching developing / approaching thunderstorms. Signs include:thunderstorms. Signs include:
• Dark, threatening clouds … Dark, threatening clouds … increasing in number / growing increasing in number / growing verticallyvertically
• Steadily increasing winds / wavesSteadily increasing winds / waves
• Flashes of lightningFlashes of lightning
• Heavy static heard on AM RadioHeavy static heard on AM Radio
Marine Safety
When a thunderstorm approaches:When a thunderstorm approaches:
• Head for shore, if possibleHead for shore, if possible• While still in the boat, make sure to While still in the boat, make sure to
have on your personal flotation have on your personal flotation device and prepare for higher winds device and prepare for higher winds and wavesand waves
• When onshore, get out of the boat When onshore, get out of the boat and seek shelter immediatelyand seek shelter immediately
Waterspout – west of Crisfield, MD 3:30 PM EDT Sunday September 10, 2006
Waterspout characteristics:
• Short-lived ( usually <30 min.)• Form from small showers or cumulus congestus)• Move rapidly if associated with fast-moving
shower• 10- to 100-feet wide; move at 5 to 75 mph• Visible funnel extends from a few 100 ft up to
cloud base (~2000 ft over the Ches. Bay)• Spin either clockwise or counter-clockwise• Visible funnel forms from cooling of humid air
due cooling/expansion (not by sucking the water!)• Are called a tornado if it makes landfall• Are difficult to detect by radar (little warning)• Most common in late summer through the fall• DO NOT GO NEAR THEM!!!!
Waterspout life cycle:
1. Dark spot: (light inner circle <100 ft dia. surrounded by a larger dark area of more diffuse shape/edges (no visible funnel)
2. Spiral pattern: alternating light/dark spiral bands (vortex growth)
3. Spray ring: swirling annulus of sea-spray (min winds ~50 mph)
4. Mature vortex: prominent visible funnel; full spiral pattern; max winds 60-100 mph; funnel extends to cloud base
5. Decay: can occur abruptly when inflow air is cut off; displays maximum vertical tilt
BAD WEATHER ON THE BAY?Report your observations to the National Weather Service and help us to improve your Report your observations to the National Weather Service and help us to improve your
Bay forecasts through reports of what is really happening.Bay forecasts through reports of what is really happening.
We are interested in winds and wave height estimates, current weather conditions, low We are interested in winds and wave height estimates, current weather conditions, low visibilities in fog, and icing. visibilities in fog, and icing.
Immediate reports have a direct impact on marine forecasts and warnings for you and Immediate reports have a direct impact on marine forecasts and warnings for you and your fellow mariners. However, even old reports are helpful as they can be your fellow mariners. However, even old reports are helpful as they can be reviewed to help improve future marine forecasts.reviewed to help improve future marine forecasts.
Call our marine report hotline at Call our marine report hotline at 1-800-253-70911-800-253-7091 or email us at or email us at [email protected] with your marine reports! with your marine reports!
Marine Reporting System
• 1-800-253-70911-800-253-7091
• Report:Report:– Location (lat/lon)Location (lat/lon)
– Wind direction and Wind direction and speedspeed
– Wave height Wave height estimatesestimates
– Weather and Weather and obstructions to obstructions to visibility, if anyvisibility, if any
Part II Outline
• The AtmosphereThe Atmosphere• The Water CycleThe Water Cycle• Weather InstrumentationWeather Instrumentation• Weather BasicsWeather Basics
– CloudsClouds– Fronts and air massesFronts and air masses– ThunderstormsThunderstorms– Lightning Lightning – HurricanesHurricanes
Earth’s Atmosphere
Layers of the Atmosphere
• Temperature is used to Temperature is used to define the layers of the define the layers of the atmosphere atmosphere
• The The Troposphere Troposphere contains all of the contains all of the weather!weather!
Pressure
• “The exertion of force upon a surface by a fluid (e.g., the atmosphere) in contact with it.”
• Meteorologists use areas of higher or lower pressures to forecast the weather.
• Low pressure systems usually come with cold fronts. High pressure systems usually build behind the cold front, allowing pleasant weather for a day or two.
Measuring Pressure
• Barometer
Wind
• Air in motion relative to Air in motion relative to the earth's surface the earth's surface
• Air moves in 3 dimensionsAir moves in 3 dimensions
Observing Wind• Anemometer
• Wind sock
• Weather Vane
• Described with both distance and speed (mph)
Why does the Wind Blow?
1. Pressure Gradient Force
Force is due to differences in pressure.
Tries to move air to eliminate pressure differences by causing air to flow from high pressure to low pressure
Why does the Wind Blow?
2. Coriolis Force
Force is due to the earth's rotation.
Causes moving objects (i.e. air, planes, birds, etc) to deflect to the right of their motion in the Northern Hemisphere
Why does the Wind Blow?
3. Friction
The earth’s surface is rough
Force that causes air to slow down and spiral into lows and out of highs.
Temperature
• A measure of the internal energy that a substance contains.
• This is the most measured quantity in the atmosphere.
Observing Temperature
• Thermometer
• Touch• Degrees Fahrenheit (F) or
Celsius (C)
Dewpoint Temperature
• Measure of the moisture content in the Measure of the moisture content in the atmosphere atmosphere
• High Dewpoint Temperature means there is High Dewpoint Temperature means there is high water vapor content high water vapor content the air is moist or the air is moist or HumidHumid
The Water Cycle
• The continuous The continuous movement of water movement of water between the earth and between the earth and the atmosphere the atmosphere
• Four Important Steps Four Important Steps are…are…
The Water Cycle
1. Evaporation and TranspirationEvaporation Evaporation when a substance changes when a substance changes from the liquid phase to the gas phasefrom the liquid phase to the gas phase
Water Water VaporTranspiration Transpiration evaporation of water evaporation of water through plant membranes through plant membranes
How water vapor, which is needed for clouds How water vapor, which is needed for clouds and precipitation, enters the atmosphere. and precipitation, enters the atmosphere.
The Water Cycle
2. Condensation
Condensation Condensation when a substance changes when a substance changes from the gas phase to the liquid phase from the gas phase to the liquid phase
Water Vapor Water
Condensation can be observed in the atmosphere Condensation can be observed in the atmosphere as clouds, fog, dew, or frost form. as clouds, fog, dew, or frost form.
The Water Cycle
3. PrecipitationPrecipitation water, either liquid or solid, that falls from the atmosphere to the surface.
Clouds are composed of millions of water droplets that have condensed. These water droplets grow into larger droplets. Eventually, the droplets can grow large enough that they will not be able to stay suspended in the cloud. When this occurs, they fall out of the cloud as precipitation.
The Water Cycle
4. Ground Water and RunoffGroundwater precipitation is absorbed into the ground
Runoff precipitation flow into streams when the ground cannot absorb any more water
Some of the runoff will evaporate and some of the groundwater will be taken in by plants and then transpired.
Precipitation
• The process where water vapor condenses in the atmosphere to form water droplets that fall to the Earth as rain, sleet, snow, hail, etc.
• We want to measure what type and how much!
• The type depends on temperature.
Measuring Precipitation
• Measure LIQUID precipitation in a rain gage.
• For SOLID precipitation (snow or ice), measure with a ruler. You can also melt the snow or ice and pour it in a rain gage.
Weather Instruments
• Weather Instruments tell us what’s happening…especially for things we can’t see.
• We measure Wind, Precipitation, Temperature and Pressure.
• We use Radar, Satellites, and even Balloons!
Doppler Radar
• Tower is 100 feet tall! The 30 ft. wide white ball on top is where the radar dish is.• Radar dish inside is 25 feet wide and spins constantly. It can see up to 250 miles away!• Radar waves sent out hit a storm cloud.• Some of the radar wave bounces off the cloud back to the radar. More waves are returned to the radar if the storm has hail or very heavy rain. It can even tell which way the wind is moving!
Satellites
• Satellites are sent high Satellites are sent high above the earth to take above the earth to take “pictures” of the clouds “pictures” of the clouds from above. This is a from above. This is a view that people usually view that people usually don’t get to see.don’t get to see.
Weather Balloons• NWS Offices across the
US release a weather balloon twice a day, once in the morning and again at night.
• The balloon has an Instrument packet that sends temperature, wind, and moisture data back to a computer.
Weather Balloons
• Data sent back from Data sent back from the Instrument Pack the Instrument Pack is plotted on a graph is plotted on a graph and sent to large and sent to large computer processors computer processors in Maryland to create in Maryland to create Numerical Weather Numerical Weather PredictionsPredictions
Weather-Makers!
The basics of Weather help forecasters know…
What will happen next?
Forecasting the Weather
• In order to forecast the weather, meteorologists need to know “What’s going on?”
• We look at all of the parts of the weather (temperature, wind, pressure, precipitation).
• Then we look at what is causing the parts to behave like they do.
Fronts and Air Masses
• An air mass is a large body of air with generally uniform temperature and humidity.
• Fronts are the boundaries between two air masses.
• Fronts are classified as to which type of air mass (cold or warm) is replacing the other.
Clouds
Cloud Formation
• Clouds are made of water, either liquid or solidClouds are made of water, either liquid or solid• Clouds typically form when air rises. Clouds typically form when air rises. • When air rises, the air's temperature cools and may reach When air rises, the air's temperature cools and may reach
its dewpoint temperature, at which point it becomes its dewpoint temperature, at which point it becomes saturated.saturated.
• Once saturated, condensation occurs and the water vapor Once saturated, condensation occurs and the water vapor in the air will condense into tiny water droplets. in the air will condense into tiny water droplets.
• As millions of droplets form, a cloud will begin to take As millions of droplets form, a cloud will begin to take shape.shape.
How to Name that Cloud!
• Height (High, middle, Height (High, middle, low, or vertically low, or vertically developing)developing)
• Physical appearance Physical appearance
• Produce precipitationProduce precipitation
Naming of Clouds
• Latin rootsLatin roots
““cirrocirro“ “ high, ‘curl of hair‘ high, ‘curl of hair‘
““altoalto“ “ ‘middle‘ ‘middle‘
““stratusstratus“ “ layer, sheet-like, low layer, sheet-like, low
““cumuluscumulus“ “ heap-like, puffy heap-like, puffy
““nimbusnimbus“ “ clouds producing precipitation clouds producing precipitation
• Combinations can be made of the Latin roots Combinations can be made of the Latin roots
High Clouds
• Form above 20,000 feet Form above 20,000 feet (6000 meters) (6000 meters)
• Composed of ice Composed of ice crystalscrystals
• Typically thin and Typically thin and white, but can be many white, but can be many different colors due to different colors due to the angle of the sunthe angle of the sun
Examples Cirrus, Cirrostratus, Cirrocumulus
Mid-level Clouds
• Bases between 6,500 to Bases between 6,500 to 20,000 feet (2000 to 20,000 feet (2000 to 6000 meters)6000 meters)
• Composed of either Composed of either water droplets or ice water droplets or ice crystals depending on crystals depending on time of yeartime of year
Examples Altostratus, Altocumulus
Low Clouds
• Bases below 6,500 feet Bases below 6,500 feet (2000 meters) (2000 meters)
• Mostly composed of Mostly composed of water dropletswater droplets
• May contain some ice May contain some ice particles and snow if particles and snow if temperatures are cold temperatures are cold enoughenough
Example Stratus, Stratocumulus, Nimbostratus
Vertically Developing Clouds
• Span the depth of the Span the depth of the troposphere troposphere
• Flat base; can grow to Flat base; can grow to heights exceeding 39,000 heights exceeding 39,000 feet (12,000 meters)feet (12,000 meters)
• They can contain both They can contain both liquid droplets and ice liquid droplets and ice particles.particles.
• Can become powerful Can become powerful thunderstorms thunderstorms
Example Cumulus, Cumulonimbus
Thunderstorms• Needed Ingredients for a Thunderstorm:
Moisture (1), Instability (2) and Lift (3)
(1)
(2)
(3)
Thunderstorm Hazards
• Lightning
• Flash Floods
• Hail
• Tornadoes
Lightning• One of the oldest observed
natural phenomena on earth, but one of the least understood.
• A gigantic spark of static electricity
• Can be seen in volcanic eruptions, extremely intense forest fires, heavy snowstorms, large hurricanes.
• Most often seen in thunderstorms.
• Intra-cloud, Cloud-to-Ground, Cloud-to-Cloud, Cloud-to-Air
How Much Lightning?
• 2,000 thunderstorms at any moment
• Nearly 14.5 MILLION storms each year
• Lightning flashes about 40 times a second worldwide.
• Satellites help us see lightning around the world.
How Lightning is Created
Thunder
• A shock wave starts at each point along the path of the lightning bolt.
• Nearby lightning strikes produce thunder that is loud and short.
• As the shock wave moves away from the strike center, it stretches, diminishes, and becomes elongated. Then other shock waves from more distance locations arrive at the listener.
• At large distances from the center, the shock wave (thunder) can be many miles across. To the listener, the combination of shock waves gives
thunder the continuous rumble we hear.
Tornadoes
• A tornado is a violently rotating column of air descending from a thunderstorm and in contact with the ground.
• Although tornadoes are usually brief, lasting only a few minutes, they can sometimes last for more than an hour and travel several miles causing considerable damage.
Hail• Hail is precipitation that is formed
when updrafts in thunderstorms carry raindrops upward into extremely cold areas of the atmosphere.
• Hail can damage aircraft, homes and cars, and can be deadly to livestock and people.
• One of the people killed during the March 28, 2000 tornado in Fort Worth was killed when struck by grapefruit-size hail.
• La Plata, MD - 4.5 inches diameter on April 28, 2002
• Impact at speeds over 100 mph!• Sign of a powerful storm .
Flash Floods
• Except for heat related fatalities, more deaths occur from flooding than any other hazard.
• Most flash floods are caused by slow moving thunderstorms, thunderstorms that move repeatedly over the same area or heavy rains from tropical storms and hurricanes.
• These floods can develop within minutes or hours.
Tropical Cyclones
Tropical Cyclone Basics
Conditions that must be in place before a TC can form:Conditions that must be in place before a TC can form: a) Warm ocean waters (at least 80F) through a depth of about a) Warm ocean waters (at least 80F) through a depth of about
150 feet.150 feet. b) An atmosphere which cools fast enough with height such that b) An atmosphere which cools fast enough with height such that
it is potentially unstable to moist convection.it is potentially unstable to moist convection. c) Relatively moist air near the mid-levels of the atmosphere c) Relatively moist air near the mid-levels of the atmosphere
(10-18 kft).(10-18 kft). d) Generally a minimum distance of 300 miles from the equator.d) Generally a minimum distance of 300 miles from the equator. e) A pre-existing near surface disturbance.e) A pre-existing near surface disturbance. f) Low values (<20 kt) of vertical wind shear between the f) Low values (<20 kt) of vertical wind shear between the
surface and the upper troposphere. Wind shear is the change surface and the upper troposphere. Wind shear is the change of wind speed/direction with height.of wind speed/direction with height.
Tropical Cyclone Classification
StagesStages Sustained wind speedsSustained wind speeds
Tropical DepressionTropical Depression Closed circulationClosed circulation
(less than 39 MPH)(less than 39 MPH)
Tropical StormTropical Storm 39-73MPH39-73MPH
HurricaneHurricane 74 MPH or higher74 MPH or higher
Saffir-Simpson Hurricane Scale(based on wind speed alone)
CategoryCategory Wind Speed Wind Speed (MPH) (MPH)
DamageDamage
11 74-9574-95 MinimalMinimal
22 96-11096-110 ModerateModerate
33 111-130 111-130 ExtensiveExtensive
44 131-155131-155 ExtremeExtreme
55 >155 >155 CatastrophicCatastrophic
TC Structure
Hurricane Hazards
• Storm SurgeStorm Surge
• High WindsHigh Winds
• FloodingFlooding
• TornadoesTornadoes
Katrina, 2005 in Louisiana
Storm Surge• Greatest potential for loss of life related to a Greatest potential for loss of life related to a
hurricane is from a storm surge.hurricane is from a storm surge.
• Storm Surge= water that is pushed toward the Storm Surge= water that is pushed toward the shore by the force of the winds swirling shore by the force of the winds swirling around the storm.around the storm.
Generalizations of Storm Surge
• More intense storms cause higher surges. More intense storms cause higher surges.
• Highest surges occur usually to the right of the Highest surges occur usually to the right of the storm track. storm track.
• Fast moving storms = higher surges along the Fast moving storms = higher surges along the open coast. open coast.
• Slow moving storms=greater flooding inside Slow moving storms=greater flooding inside bays and estuaries.bays and estuaries.
Storm Surge
High Winds
• SatellitesSatellites, , reconnaissance aircraftreconnaissance aircraft, and land based , and land based radarsradars are used to estimate the maximum surface are used to estimate the maximum surface wind speed in a hurricane. The intensity of a land-wind speed in a hurricane. The intensity of a land-falling hurricane is expressed in terms of categories falling hurricane is expressed in terms of categories that relate wind speeds and potential damage. NHC that relate wind speeds and potential damage. NHC uses the Saffir-Simpson Hurricane scale to classify uses the Saffir-Simpson Hurricane scale to classify hurricanes. Each time you go up a category, the hurricanes. Each time you go up a category, the damage goes up roughly by a factor of five. So, a damage goes up roughly by a factor of five. So, a category four hurricane will produce 25 times more category four hurricane will produce 25 times more damage than a category two hurricane.damage than a category two hurricane.
High winds
• High rise buildings are also vulnerable to High rise buildings are also vulnerable to hurricane force winds, particularly at the hurricane force winds, particularly at the higher levels since wind speeds tend to higher levels since wind speeds tend to increase with height. Recent research suggests increase with height. Recent research suggests that winds increase one category as you go up that winds increase one category as you go up 500 ft. 500 ft.
• This is why is not uncommon for high rise This is why is not uncommon for high rise buildings to suffer a great deal of damage due buildings to suffer a great deal of damage due to windows being blown out.to windows being blown out.
High Winds
• Why do winds weaken as you go inland?Why do winds weaken as you go inland? • They weaken due to friction caused by land They weaken due to friction caused by land
and because hurricanes, once they move and because hurricanes, once they move inland, lose their energy source which is the inland, lose their energy source which is the very warm waters of the ocean. very warm waters of the ocean.
• A category four hurricane at landfall can A category four hurricane at landfall can weaken very rapidly to a category one in just weaken very rapidly to a category one in just six hours. This is because is a function of time six hours. This is because is a function of time and not distance, faster moving storms are and not distance, faster moving storms are going to push those winds inland more going to push those winds inland more effectively than slower moving ones.effectively than slower moving ones.
Damage done by Andrew 1992
Wind-blown debris can become deadly projectiles
Tornadoes
• Typically occur on the right side of the storm Typically occur on the right side of the storm because of an influx of very warm moist air. because of an influx of very warm moist air.
• As the hurricane is making landfall, winds at As the hurricane is making landfall, winds at the surface begin to slow down due to friction, the surface begin to slow down due to friction, while winds a mile above the ground are still while winds a mile above the ground are still spinning very rapidly creating a favorable spinning very rapidly creating a favorable wind profile for tornadoes to form. wind profile for tornadoes to form.
Tornadoes
• When associated with hurricanes, tornadoes When associated with hurricanes, tornadoes are not usually accompanied by hail or a lot of are not usually accompanied by hail or a lot of lightning.lightning.
• Tornado production can occur for days after Tornado production can occur for days after landfall when the TC remnants maintain an landfall when the TC remnants maintain an identifiable low pressure circulation.identifiable low pressure circulation.
• They can also develop at any time of the day They can also develop at any time of the day or night during landfall. or night during landfall.
• Classified using the Enhanced-Fujita Scale.Classified using the Enhanced-Fujita Scale.
Inland Flooding
• Intense rainfall is not directly related to the Intense rainfall is not directly related to the wind speed of tropical cyclones. Some of the wind speed of tropical cyclones. Some of the greatest rainfall amounts occur from weaker greatest rainfall amounts occur from weaker storms that drift slowly or stall over an area.storms that drift slowly or stall over an area.
• Inland flooding can be a major threat to Inland flooding can be a major threat to communities hundreds of miles from the coast.communities hundreds of miles from the coast.
• In a study from 1970 to 1999, freshwater In a study from 1970 to 1999, freshwater flooding accounted for more than half (59%) flooding accounted for more than half (59%) of U.S. tropical cyclone deaths.of U.S. tropical cyclone deaths.
