The Winter 2011-2012 Winter Recap and Spring

Outlook

The Winter 2011-2012 Winter Recap and Spring

Outlook

Jason HansfordSenior Forecaster

National Weather Service Forecast Office Shreveport, LA

December RainfallDecember Rainfall

December Observed Rainfall

Departure From Normal

2011 Total Precipitation2011 Total Precipitation

City: 2011 Total

Precip.

Departure from Normal

Rank (Driest)

2010 Total Precip.

Shreveport, LA 33.07 in. -18.34 in. 17th 30.73 in.

Monroe, LA 49.52 in. -4.50 in. ------- 43.01 in.

Texarkana, AR 30.69 in. -18.96 in. 11th 29.48 in.

El Dorado, AR 37.62 in. -15.30 in. 15th 34.26 in.

Tyler, TX 24.97 in. -20.82 in. 3rd 31.07 in.

Longview, TX 30.54 in. -17.01 in. 9th 26.82 in.

Lufkin, TX 33.77 in. -15.18 in. 21st 30.01 in.

December-March Rainfall December-March Rainfall

Departure From Normal

90 Day Observed Rainfall

April Rainfall (Ending 4/16/12)April Rainfall (Ending 4/16/12)

Observed Rainfall

Departure From Normal

Cumulative Winter RainfallCumulative Winter Rainfall

City: Dec. - Feb. Rainfall

Departure from Normal

% of Normal

Shreveport, LA 14.63 inches +0.91 inches 107%

Monroe, LA 18.04 inches +3.11 inches 121%

Texarkana, AR 11.27 inches -1.17 inches 91%

De Queen, AR 8.60 inches -2.76 inches 76%

El Dorado, AR 14.58 inches +0.31 inches 102%

Tyler, TX 11.88 inches +0.77 inches 107%

Longview, TX 13.31 inches +1.46 inches 112%

Lufkin, TX 15.25 inches +2.76 inches 122%

March FloodingMarch Flooding• Significant rainfall (widespread 4-8 inches, isolated

amounts > 10-12 inches) area wide.

• Drought has been eliminated across most areas.

• Significant rainfall (widespread 4-8 inches, isolated amounts > 10-12 inches) area wide.

• Drought has been eliminated across most areas.

March Month to Date Rainfall:

Departure from Normal:

The March Flood ContributorThe March Flood Contributor

March Monthly Rainfall March Monthly Rainfall

City: March Rainfall: Departure from Normal:

Rank for Wettest March

on Record:

Shreveport, LA 7.94 in. +3.80 in. 10th

Monroe, LA 10.67 in. +5.95 in. 2nd

Texarkana, AR 5.52 in. +1.32 in. -----

El Dorado, AR 8.77 in. +4.02 in. 9th

De Queen, AR 5.27 in. +0.63 in. -----

Tyler, TX 6.38 in. +2.26 in. -----

Longview, TX 4.77 in. +0.42 in. -----

Lufkin, TX 8.67 in. +4.89 in. 2nd

Hydrological Drought Impacts Hydrological Drought Impacts

Cane River in Natchitoches, LA

Measured near 2 ft. on 10/11/11

(Photo courtesy of Wiley Butler)

Cane River in Natchitoches, LA

Measured near 2 ft. on 10/11/11

(Photo courtesy of Wiley Butler)

Cane River in Natchitoches, LA

Taken 3/21/12 around 10 am

(Photo courtesy of Wiley Butler)

Cane River in Natchitoches, LA

Taken 3/21/12 around 10 am

(Photo courtesy of Wiley Butler)

Hydrological Drought Impacts Hydrological Drought Impacts

Cane River in Natchitoches, LA

June 17th, 2011 (Photo courtesy of Wiley Butler)

Cane River in Natchitoches, LA

June 17th, 2011 (Photo courtesy of Wiley Butler)

Cane River in Natchitoches, LA

March 21st, 2012

(Photo courtesy of Wiley Butler)

Cane River in Natchitoches, LA

March 21st, 2012

(Photo courtesy of Wiley Butler)

Calculated Soil Moisture(Ending March 24, 2012)Calculated Soil Moisture(Ending March 24, 2012)

Soil Moisture has INCREASED to 500-600

mm (20-24 in.) deep!

Soil Moisture has returned to near/slightly

above normal!

Calculated Soil Moisture (Ending April 13, 2012)

Calculated Soil Moisture (Ending April 13, 2012)

Soil Moisture ComparisonSoil Moisture Comparison

Drought Severity IndicesDrought Severity Indices• Palmer Drought Severity Index: Is most

effective in determining long term drought by using temperature and precipitation to calculate dryness. It is also standardized to the local climate.

a) Measured on a scale of -4 to 4, with negative values indicating drought, and positive values indicating moisture surplus.

• Crop Moisture Index (CMI): Is a short term drought index, based on precipitation, dryness, and wetness affecting agriculture. It changes more rapidly from week to week than the Palmer Index.

a) Uses the same scale as the Palmer Index.

• Palmer Drought Severity Index: Is most effective in determining long term drought by using temperature and precipitation to calculate dryness. It is also standardized to the local climate.

a) Measured on a scale of -4 to 4, with negative values indicating drought, and positive values indicating moisture surplus.

• Crop Moisture Index (CMI): Is a short term drought index, based on precipitation, dryness, and wetness affecting agriculture. It changes more rapidly from week to week than the Palmer Index.

a) Uses the same scale as the Palmer Index.

Palmer/Crop Moisture IndexPalmer/Crop Moisture Index

U.S. Drought Monitor (April 17th, 2012)

U.S. Drought Monitor (April 17th, 2012)

U.S. Drought Monitor(October 25th, 2011)

U.S. Drought Monitor(October 25th, 2011)

2011 Avg. Monthly Temperature

2011 Avg. Monthly Temperature

City: 2011 Avg. Monthly Temp.

Departure from Normal:

Rank:

Shreveport, LA 68.2° +2.5° T4th (with 1927 and 2006)

Monroe, LA 68.2° +2.4° 1st

Texarkana, AR 66.0° +2.1° T5th (with 2005)

El Dorado, AR 64.4° +0.9° T20th (with 1945 and 2004)

Tyler, TX 69.1° +3.7° 2nd (behind 1921 at 69.6°)

Longview, TX 68.5° +3.1° T1st (with 1911)

Lufkin, TX 68.9° +2.1° 2nd (behind 1998 at 69.1°)

CONUS Temperature Departure from Normal

CONUS Temperature Departure from Normal

Winter Temperature Comparison (“The Winter That

Wasn’t”)

Winter Temperature Comparison (“The Winter That

Wasn’t”)City: Dec. – Feb.

Avg. Temperature:

Departure from Normal:

Warmest Winters Rank:

Shreveport, LA 52.6° +4.0° 14th

Monroe, LA 51.9° +3.6° 4th

Texarkana, AR 49.0° +3.2° 17th

El Dorado, AR 47.2° +1.5° 31st

Tyler, TX 51.0° +2.7° 8th *

Longview, TX 51.3° +3.1° 8th

Lufkin, TX 53.6° +3.0° T10th *** Tied for 8th warmest winter on record with 1997. Sporadic records since 1895.

** Tied for 10th warmest winter on record with 2000.

Records since 1906.

Month by Month TemperatureComparison for Shreveport, LA

(Nov. 2011 – April 15th, 2012)

Month by Month TemperatureComparison for Shreveport, LA

(Nov. 2011 – April 15th, 2012)

March Avg. Temperature March Avg. Temperature

City: March Avg. Temperature:

Departure from Normal:

Rank for Warmest March

on Record:

Shreveport, LA 67.3° +9.4° 1st

Monroe, LA 68.0° +10.0° 1st

Texarkana, AR 64.8° +8.9° 3rd

El Dorado, AR 63.0° +7.2° 3rd

De Queen, AR 61.2° +8.0° 2nd

Tyler, TX 65.6° +8.7° 3rd

Longview, TX 65.9° +8.3° 3rd

Lufkin, TX 67.2° +7.6° 2nd

Arctic OscillationArctic Oscillation• Refers to the atmospheric circulation pattern in the northern

middle and high latitudes in the Arctic. These can generate strong shifts in the climate pattern than can overwhelm or amplify the typical La Niña impacts.

1) Exhibits a negative phase when higher pressures develop over the Polar region, and low pressures develop in the mid- latitudes (near 45°N). This results in frigid air plunging south into North America east of the Rockies.

2) Exhibits a positive phase when lower pressures develop over the Polar region, and higher pressures develop in the mid- latitudes. This will keep the frigid air locked up in the Arctic region, but also drives ocean storms farther north. Thus, wetter weather is usually associated throughout Alaska, Scotland, and Scandinavia.

• Refers to the atmospheric circulation pattern in the northern middle and high latitudes in the Arctic. These can generate strong shifts in the climate pattern than can overwhelm or amplify the typical La Niña impacts.

1) Exhibits a negative phase when higher pressures develop over the Polar region, and low pressures develop in the mid- latitudes (near 45°N). This results in frigid air plunging south into North America east of the Rockies.

2) Exhibits a positive phase when lower pressures develop over the Polar region, and higher pressures develop in the mid- latitudes. This will keep the frigid air locked up in the Arctic region, but also drives ocean storms farther north. Thus, wetter weather is usually associated throughout Alaska, Scotland, and Scandinavia.

Arctic Oscillation (Nov. – Mar. 1950 - Current)

Arctic Oscillation (Nov. – Mar. 1950 - Current)

Limitations to Forecasting:Limitations to Forecasting:

Strong AO episodes typically last only a few weeks, and are difficult to predict more than a week or two in advance.

Limitations to Forecasting:Limitations to Forecasting:

Strong AO episodes typically last only a few weeks, and are difficult to predict more than a week or two in advance.

North Atlantic OscillationNorth Atlantic Oscillation Fluctuations in the difference of Fluctuations in the difference of

sea-level pressure between the sea-level pressure between the Icelandic Low and the Azores Icelandic Low and the Azores high.high.

+ NAO prevents cold air from + NAO prevents cold air from plunging southward over eastern plunging southward over eastern North America.North America.

Shows multi-decadal signal.Shows multi-decadal signal.

Has an effect on Hurricanes in Has an effect on Hurricanes in the Atlantic. (During +NAO the Atlantic. (During +NAO events, the Bermuda High is events, the Bermuda High is weaker, allowing for a more W-E weaker, allowing for a more W-E flow across the Atlantic. SST’s in flow across the Atlantic. SST’s in the Atlantic are also unusually the Atlantic are also unusually cold following +NAO winters.) cold following +NAO winters.)

Historical NAO IndexHistorical NAO Index

Strong positive Strong positive anomalies this past anomalies this past winter.winter.

Strong negative Strong negative anomalies last anomalies last winter.winter.

Monthly Observed Arctic and North Atlantic Oscillation

Indices

Monthly Observed Arctic and North Atlantic Oscillation

Indices

SST’s in the Equatorial PacificSST’s in the Equatorial Pacific

Niño 3.4 Region:Niño 3.4 Region:5°N - 5°S and 170° - 120°W

[ ] [ ]

Long Term SST AnomaliesLong Term SST Anomalies

La Nina is Ending! So, What’s Next?!

La Nina is Ending! So, What’s Next?!

Probabilistic ENSO ForecastProbabilistic ENSO Forecast

Spring OutlookSpring Outlook

TemperatureTemperature PrecipitationPrecipitation

20 Month Rainfall and Departures (Mar. ’10-Apr. 11 ‘12)

20 Month Rainfall and Departures (Mar. ’10-Apr. 11 ‘12)

City: Total Precipitation:

Departure from Normal:

% of Normal:

Shreveport, LA 75.07 -33.21 69%

Monroe, LA 107.28 -6.73 94%

Natchitoches, LA 96.86 -20.60 82%

Texarkana, AR 68.11 -36.67 65%

El Dorado, AR 84.67 -27.18 76%

Hope, AR 82.06 -34.45 70%

Dequeen, AR 74.20 -29.75 71%

Idabel, OK 84.08 -25.70 77%

Mt. Pleasant, TX 70.45 -29.96 70%

Tyler, TX 65.26 -31.22 68%

Longview, TX 64.73 -35.63 64%

Lufkin, TX 76.16 -26.30 74%

Long Term Drought OutlookLong Term Drought Outlook

The EndThe End

Any Questions???Any Questions???