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FXUS25 KWNC 271330
PMDDRO
US DROUGHT MONITOR DISCUSSION
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
830 AM EST THU 27 MAR 2008
NATIONAL DROUGHT SUMMARY MARCH 25, 2008 THE SOUTHEAST AND
MID-ATLANTIC:ON THE HEELS OF RECENT RAINS, SLOW AND STEADY
IMPROVEMENT CONTINUES FOR MANY PARTS OF THESE REGIONS. HEAVY
RAINS LIKE THOSE SEEN IN THE MISSISSIPPI AND OHIO RIVER VALLEYS
HAVE MISSED THE CORE DROUGHT REGION THUS FAR. WORTH HIGHLIGHTING
THIS WEEK IS THAT WITH THE REMOVAL OF THE D4 IN TENNESSEE
AND ALABAMA, THE UNITED STATES IS D4-FREE FOR THE FIRST TIME
SINCE MAY 2007. IMPRESSIVE LONG-TERM DEFICITS STILL REMAIN AND
HYDROLOGIC RECOVERY TYPICALLY LAGS THE IMMEDIATE SHORT-TERM
BENEFITS SEEN WITH THE GREENING UP OF SPRING. OTHER CHANGES
IN THE REGION INCLUDE THE TRIMMING /IMPROVEMENT/ OF D0-D3 ON
THE WESTERN AND NORTHERN EDGES IN MISSISSIPPI AND TENNESSEE
AND EXTREME WESTERN NORTH CAROLINA. TO THE SOUTH IN FLORIDA,
SOME HEAVIER RAINS IN THE SOUTHERN PENINSULA /EVERGLADES REGION/
TOTALED ANYWHERE FROM 2 TO 4 INCHES, LEADING TO THE REMOVAL OF
THE D3 CORE THAT WAS CENTERED OFF THE WESTERN SHORE COUNTIES
OF LAKE OKEECHOBEE. OTHER IMPROVEMENTS HERE INCLUDE A TRIMMING
OF D0-D2 ON THE EASTERN AND NORTHERN SHORES OF THE LAKE AS
WELL. LONG-TERM DRYNESS IS STILL REFLECTED BY LOW GROUNDWATER
LEVELS AS FAR SOUTH AND EAST AS DADE COUNTY. THE PLAINS: GOOD
MOISTURE FROM HEAVY SNOWS /A NICE 1-INCH WATER EQUIVALENT/
LAST WEEK IN NORTHEASTERN SOUTH DAKOTA AND SOUTHEASTERN NORTH
DAKOTA HAS BROUGHT ABOUT SOME IMPROVEMENT TO THE D1 THERE. THE
PRECIPITATION MISSED THE WESTERN DAKOTAS AND EASTERN MONTANA,
LEADING TO SOME EXPANSION OF DROUGHT CONDITIONS THERE. IN
MONTANA, D0 NOW COVERS ALL OF THE EASTERN COUNTIES AND D1 AND
D2 HAVE PUSHED SLIGHTLY TO THE SOUTH AND EAST. THE LACK OF
SNOW COVER AND/OR RAINS COUPLED WITH HIGH WINDS THIS SPRING,
HAVE ALREADY RESULTED IN SEVERAL PRE-SEASON FIRES. IN THE
SOUTHERN PLAINS, FIRE RISK IS STILL CRITICALLY HIGH IN WESTERN
AND SOUTHERN TEXAS ALONG WITH PARTS OF WESTERN OKLAHOMA. AFTER
ANOTHER DRY AND WARM WEEK, BOTH D0 AND D1 HAVE ADVANCED SLIGHTLY
TO THE EAST IN NORTHWESTERN OKLAHOMA. IN WEST-CENTRAL TEXAS,
THE WET PATTERN CONTINUED FOR SOME THIS PAST WEEK. GOOD RAINS
/1.5 TO 3 INCHES OR MORE IN PLACES/ HAVE EATEN AWAY AT SOME
OF THE WESTERN AND NORTHERN EDGES OF THE D1/D2 IN THE AREA,
PUSHING THE SEVERE AND EXTREME DROUGHT CORE /D2/D3/ TO THE
SOUTH, WHERE D2 HAS ACTUALLY PUSHED FARTHER SOUTH THIS WEEK
ALONG THE RIO GRANDE TOWARD BROWNSVILLE. THIS CORE REGION OF D2
AND D3 HAS ONLY SEEN 50 PERCENT OR LESS OF NORMAL PRECIPITATION
SINCE OCTOBER OF LAST YEAR. THE WEST: THE MONTH OF MARCH HAS
ONLY BEEN HOLDING SERVE AS FAR AS LATE SEASON PRECIPITATION IS
CONCERNED, AND THE GENERALLY COOLER AND BENEFICIAL WEATHER OF
LATE GAVE WAY TO WARMER READINGS THIS PAST WEEK.ACCORDING TO
USDA-NRCS, THE LATEST SNOW WATER EQUIVALENT READINGS WITHIN MOST
OF THE BASINS EAST OF THE SIERRAS ARE ONLY AT, OR JUST BELOW,
100 PERCENT OF NORMAL, SO THE SITUATION IS TENUOUS AS THE SNOW
SEASON WINDS DOWN. SOME LATE-SEASON STORM SYSTEM BOOSTS WOULD
BE VERY MUCH WELCOMED. ONE AREA THAT HAS MADE OUT PRETTY WELL
THIS WINTER /WATER YEAR/ HAS BEEN THE MOHAVE AND YUMA DESERT
REGIONS IN SOUTHEASTERN CALIFORNIA AND WESTERN ARIZONA,
RESPECTIVELY. WITH MUCH OF THIS AREA SEEING ABOVE-NORMAL
PRECIPITATION SINCE OCTOBER 2007, THE D2 HAS BEEN REMOVED BUT
D1 REMAINS. THERE HAS ALSO BEEN A ONE-CATEGORY IMPROVEMENT WITH
THE REMOVAL OF D1 SOUTHWARD WITHIN THE SOUTH LAHONTAN BASIN
IN EASTERN CALIFORNIA ALONG THE NEVADA BORDER AND ACROSS INTO
WEST-CENTRAL NEVADA WHERE D1 HAS BEEN PUSHED SLIGHTLY EASTWARD.
HAWAII AND PUERTO RICO: THE LACK OF RAINS OVER THE PAST 90
DAYS OR SO HAS LEFT MOST OF PUERTO RICO AT OR BELOW 50 PERCENT
OF NORMAL /6- TO 12-INCH DEFICITS/, LEADING TO BELOW-NORMAL
STREAMFLOWS. THIS HAS LEAD TO THE INTRODUCTION OF ABNORMALLY
DRY /D0/ CONDITIONS ACROSS ALL BUT THE EXTREME NORTHEAST CORNER
OF THE ISLAND. IN HAWAII, LITTLE RAIN MEANS NO CHANGES TO THE
D0 AREAS ON ALL OF THE ISLANDS THIS WEEK, AND HIGH PRESSURE
NORTH OF THE ISLANDS SHOULD GENERALLY RESULT IN LIMITED SHOWER
ACTIVITY ON THE WINDWARD SIDES THROUGH THE MIDDLE OF NEXT WEEK.
LOOKING AHEAD: DURING THE NEXT 5 DAYS /THROUGH MARCH 31/,
THE FORECAST AGAIN CALLS FOR THE HEAVIEST RAINS TO FALL JUST
WHERE THEY ARENT NEEDED IN THE MIDDLE MISSISSIPPI AND OHIO
RIVER VALLEYS. PARTS OF THE SOUTHEAST /ALONG THE NORTHERN
FRINGE FROM MISSISSIPPI, TENNESSEE, ALABAMA, AND GEORGIA/
COULD ALSO SEE SOME MORE WELCOME RAINS. A SYSTEM COMING OUT OF
THE NORTHERN ROCKIES COULD ALSO LEAD TO SOME ADDITIONAL GOOD
MOISTURE ACROSS MOST OF SOUTH DAKOTA. TEMPERATURES SHOULD REMAIN
COOLER THAN NORMAL ACROSS THE NORTHERN PLAINS AND SOUTHERN
CALIFORNIA. WARMER TEMPERATURES ARE EXPECTED ACROSS THE DESERT
SOUTHWEST, SOUTHERN PLAINS, AND WESTERN GULF COAST STATES.
THE NWS 6 TO 10 DAY OUTLOOK FOR APRIL 1-5 SHOWS THAT A STRONG
ZONAL /WEST TO EAST/ FLOW PATTERN SHOULD BUILD IN, BRINGING
WITH IT WARMER TEMPERATURES FOR MOST OF THE COUNTRY EVERYWHERE
EAST OF THE ROCKIES EXCEPT FOR FLORIDA, WHICH IS EXPECTING MORE
SEASONAL READINGS. THE ABNORMALLY DRY REGION IN ALASKA CAN
ALSO EXPECT TO SEE ABOVE-NORMAL TEMPERATURES. PRECIPITATION
FOR THIS PERIOD IS MORE OF A MIXED BAG, WITH BELOW-NORMAL
AMOUNTS EXPECTED IN SOUTHWESTERN ALASKA, THE SOUTHERN ROCKIES,
AND WESTERN TEXAS. THOSE AREAS THAT SHOULD SEE ABOVE-NORMAL
PRECIPITATION ARE AGAIN CENTERED ON THE MIDWEST AND GREAT
LAKE STATES. THE NORTHERN STATES IN THE SOUTHEAST MAY BENEFIT
FROM BEING ON THE SOUTHERN EDGE OF THIS WET PATTERN AS WELL.
AUTHOR: MARK SVOBODA, NATIONAL DROUGHT MITIGATION CENTER
DROUGHT INTENSITY CATEGORIES...
D0 ABNORMALLY DRY...
D1 MODERATE DROUGHT...
D2 SEVERE DROUGHT...
D3 EXTREME DROUGHT...
D4 EXCEPTIONAL DROUGHT
DROUGHT TYPES...
USED ONLY WHEN IMPACTS DIFFER...
A AGRICULTURAL...
H HYDROLOGIC.
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