Special Severe Special Severe Weather BriefingWeather Briefing

4/3/20114/3/2011

Keith StellmanKeith StellmanWarning Coordination Warning Coordination

MeteorologistMeteorologistNational Weather Service Shreveport, LouisianaNational Weather Service Shreveport, Louisiana

Slides Available atSlides Available atwww.srh.noaa.gov/shv/briefingwww.srh.noaa.gov/shv/briefing

Overnight/Monday Slight Risk for Severe Weather Slight Risk for Severe Weather

over entire regionover entire region Cold Front moving across regionCold Front moving across region Both high wind shear and ample Both high wind shear and ample

instability forecast thru the instability forecast thru the event..with higher amounts east in event..with higher amounts east in LA/S ARLA/S AR

Hail/High Winds…Isolated tornadoes Hail/High Winds…Isolated tornadoes (Best Chances North LA/South (Best Chances North LA/South Central AR mid to late AM with higher Central AR mid to late AM with higher low level shear)low level shear)

National Weather Service Shreveport, LouisianaNational Weather Service Shreveport, Louisiana

OverviewOverview

National Weather Service Shreveport, LouisianaNational Weather Service Shreveport, Louisiana

LL

CurrentCurrent

6 AM Monday6 AM MondayLL

Deep Moist

ure

Slight R

isk A

rea

Slight R

isk A

rea

Highest Highest Probability Probability of Severe of Severe WeatherWeather

ThreatsThreats1.1. Damaging Damaging

WindsWinds2.2. Hail Hail 3.3. Isolated Isolated

TornadoesTornadoes

Severe Weather Severe Weather MondayMonday

Timing – 6 AM MondayTiming – 6 AM Monday

Front west of Front west of the region the region moving inmoving in

Storms Storms developing developing along the linealong the line

Instability at 6 AM Instability at 6 AM Where Deep Where Deep

moisture moisture moves in… moves in… instability instability increasesincreases

Even though Even though its early… its early… instability instability will be will be sufficientsufficient

Need to Need to break Capbreak Cap

Pink > 1000 J/KGPink > 1000 J/KGRed > 1500 J/KGRed > 1500 J/KG

Timing – 9 AM MondayTiming – 9 AM Monday

Front Front Nashville-> Mt Nashville-> Mt Pleasant -> Pleasant -> TylerTyler

Storms Storms continue continue developing developing along the linealong the line

9 AM 9 AM EHI = Instability and Wind EHI = Instability and Wind

ShearShear ValuesValues

1 - 3 1 - 3 Isolated Isolated TornadoesTornadoes/ / Damaging Damaging WindsWinds

>3 - 6 >3 - 6 Strong to Strong to Violent Violent TornadoesTornadoes

Yellow = 1-2Yellow = 1-2Orange = 2-3Orange = 2-3

Red = 3-4Red = 3-4

Timing – Noon MondayTiming – Noon Monday

Front Magnolia-Front Magnolia-> Shreveport -> > Shreveport -> LufkinLufkin

Line filling inLine filling in Greater Greater

instability from instability from here eastwardhere eastward

Instability at NoonInstability at Noon Instability Instability

increases increases east as east as things warm things warm up and even up and even more more moisture moisture moves inmoves in

Very little Very little cap to cap to overcomeovercome

Pink > 1000 J/KGPink > 1000 J/KGRed > 1500 J/KGRed > 1500 J/KG

Yellow > 2000 J/KGYellow > 2000 J/KGGreen > 3000 J/KGGreen > 3000 J/KG

* ~1000 is all that is needed* ~1000 is all that is needed

NoonNoon EHI = Instability and Wind EHI = Instability and Wind

ShearShear Values decrease Values decrease dramatically dramatically ahead of the frontahead of the front

Due to wind Due to wind shear decreasing shear decreasing even though even though instability is instability is increasingincreasing

ValuesValues 1 - 3 Isolated 1 - 3 Isolated

Tornadoes/ Tornadoes/ Damaging Damaging WindsWinds

>3 - 6 Strong to >3 - 6 Strong to Violent Violent TornadoesTornadoes

Yellow = 1-2Yellow = 1-2Orange = 2-3Orange = 2-3

Red = 3-4Red = 3-4

Timing – 3 PM MondayTiming – 3 PM Monday Front East of Front East of

Monroe -> Monroe -> ColfaxColfax

Greatest Greatest instability as it instability as it moves into this moves into this regionregion

Damaging Damaging winds/Hailwinds/Hail

Forecast Rainfall TotalsForecast Rainfall Totals HeaviesHeavies

t rain in t rain in LA / LA / South South AR AR

Eastern Eastern ParisheParishes s heaviest heaviest rainfall. rainfall.

0.50

”- 0

.75”

0.50

”- 0

.75”

0.25”-0.50”0.25”-0.50”

0.75

”- 1

.25”

0.75

”- 1

.25”

Summary Slight Risk for Slight Risk for

Severe Weather Severe Weather over entire regionover entire region ImpactsImpacts

Damaging WindsDamaging Winds HailHail Isolated TornadoesIsolated Tornadoes

Front will move Front will move across the region across the region from 6 AM West – from 6 AM West – 3 PM East3 PM East

National Weather Service Shreveport, LouisianaNational Weather Service Shreveport, Louisiana

Slight R

isk A

rea

Slight R

isk A

rea

Highest Highest Probability Probability of Severe of Severe WeatherWeather

ThreatsThreats1.1. Damaging Damaging

WindsWinds2.2. Hail Hail 3.3. Isolated Isolated

TornadoesTornadoes

NEXT CONFERENCE CALL:

Thursday Thursday

04/7/2011 @ 10 AM04/7/2011 @ 10 AM

www.srh.noaa.gov/shv/www.srh.noaa.gov/shv/briefingbriefingNational Weather Service Shreveport, LouisianaNational Weather Service Shreveport, Louisiana