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FXUS25 KWNC 131230
PMDDRO
US DROUGHT MONITOR DISCUSSION
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
830 AM EST THU 13 AUG 2009
NATIONAL DROUGHT SUMMARY AUGUST 11, 2009
THE NORTHEAST AND MID-ATLANTIC: STORMS PRODUCED SOME AREAS
OF SIGNIFICANT RAINFALL, PARTICULARLY OVER UPSTATE NEW YORK
AND SOUTHEASTERN PENNSYLVANIA INTO NEW JERSEY. WEEKLY TOTALS
WERE AROUND ONE TO FOUR INCHES. IN VIRGINIA, LOCALIZED STORM
ACTIVITY WAS NOT ENOUGH TO REMEDY THE ABNORMALLY DRY CONDITIONS
IN THE EASTERN PART OF THE STATE. THIS WEEK, NO CHANGES WERE
MADE IN THE NORTHEAST OR MID-ATLANTIC.
SOUTHEAST: NEAR-NORMAL PRECIPITATION ACROSS NORTH CAROLINA,
GEORGIA AND ALABAMA LED TO NO CHANGE OF DROUGHT EXTENT OR
SEVERITY IN THESE STATES. IN FLORIDA, A MIXED BAG OF WET
AND DRY WEATHER THIS WEEK ALSO LED TO NO CHANGE OF DROUGHT
CONDITIONS. SMALL AREAS OF HEAVY RAINFALL OCCURRED ALONG
THE SOUTHWEST COAST, BUT LONG-TERM DROUGHT PREVAILS AND THE
ABNORMALLY DRY DESIGNATION REMAINS.
OHIO RIVER AND SOUTHERN MISSISSIPPI RIVER VALLEYS: IT WAS
ANOTHER WEEK OF WET WEATHER IN THIS REGION. SOUTHEASTERN
INDIANA RECORDED AS MUCH AS THREE TO FOUR INCHES OF RAIN.
ALONG THE MISSISSIPPI RIVER FROM SOUTHERN ILLINOIS TO LOUISIANA
HAS BEEN DROUGHT-FREE AS WELL AND CONTINUED TO RECEIVE RAIN
THIS WEEK. NO CHANGE IN DROUGHT EXTENT OR SEVERITY WAS MADE
THROUGHOUT THESE REGIONS.
SOUTHERN PLAINS: CONTINUED HOT AND DRY WEATHER IN SOUTHERN
TEXAS MAINTAINED THE EXTREME AND EXCEPTIONAL DROUGHT. FOR NINE
COUNTIES IN TEXAS, THE CURRENT DROUGHT IS THE WORST ON RECORD
FOR INTENSITY, SINCE 1895. AGRICULTURAL AND RANCHING IMPACTS
FROM MANY COUNTIES CONTINUE TO BE REPORTED, WITH LITTLE SURFACE
WATER AND GRASS GROWTH TO SUPPORT CATTLE.
IN OKLAHOMA, RECENT RAINS OF MORE THAN TWO INCHES IN SOME
EASTERN COUNTIES LED TO A ONE-CATEGORY IMPROVEMENT IN ADAIR
AND CHEROKEE COUNTIES.OTHER IMPROVEMENTS IN SEVERITY WERE
GAINED IN SOME WESTERN COUNTIES AS WELL, ALSO IN RESPONSE TO
RECENT RAINFALL AND IMPROVEMENTS IN SOIL MOISTURE.
PRECIPITATION DEFICITS IN CENTRAL KANSAS ARE BEGINNING TO
SHOW EARLY SIGNS OF DRY CONDITIONS. THE AREA OF ABNORMALLY
DRY /D0/ WAS EXPANDED SOUTH AND NORTH TO THE NEBRASKA BORDER.
FOR THE LAST 30 DAYS, DEFICITS IN THIS AREA ARE RUNNING AROUND
TWO INCHES, OR 50-75 PERCENT OF NORMAL.
VISUAL CROP SURVEYS IN NEBRASKA PROVIDED EVIDENCE OF WATER
STRESS IN SOME CORN AND SOYBEAN REGIONS. THE AREA OF MODERATE
DROUGHT IN SOUTH CENTRAL NEBRASKA WAS EXPANDED TO INCLUDE AREAS
NORTH AND EAST OF THERE, OVER LINCOLN AND PORTIONS OF SAUNDERS,
LANCASTER AND FILMORE COUNTIES.
NORTHERN PLAINS: SIGNIFICANT PRECIPITATION ACROSS CENTRAL
MINNESOTA AND WISCONSIN THIS WEEK LED TO IMPROVEMENTS IN
THE PREVIOUS D0-D1 REGION. LOCAL TOTALS OF OVER SIX INCHES
FELL IN PARTS OF THIS AREA. OUTSIDE OF THIS NARROW BAND,
DROUGHT CONDITIONS WORSENED TO INCLUDE A GROWING AREA OF
MODERATE DROUGHT IN SOUTHEASTERN MINNESOTA, AND AN EXTENSION
OF ABNORMALLY DRY CONDITIONS INTO NORTHERN IOWA. ELSEWHERE,
AN AREA OF ABNORMALLY DRY /D0/ WAS INTRODUCED IN SOUTHWESTERN
MINNESOTA AND NORTHWESTERN IOWA IN ROCK, NOBLES AND LYON
COUNTIES TO REFLECT PRECIPITATION DEFICITS OF GREATER THAN 50
PERCENT FOR THE LAST 30 DAYS, AND 30 PERCENT BELOW NORMAL FOR
THE LAST THREE MONTHS.
IN EASTERN SOUTH DAKOTA, A ONE-CATEGORY IMPROVEMENT WAS MADE
TO REFLECT NO DROUGHT IN AN AREA INCLUDING ROBERTS AND GRANT
COUNTIES. FURTHER NORTH, PRE-DROUGHT CONDITIONS ARE BEING
REPORTED BY AGRICULTURAL SECTORS IN NORTHWESTERN NORTH DAKOTA.
THIS WEEKS MAP NOW SHOWS D0 ACROSS THESE COUNTIES NORTH OF
THE MISSOURI RIVER. FORTUNATELY, TEMPERATURES HAVE REMAINED
COOL THIS SEASON TO DAMPEN THE IMPACT OF DRY CONDITIONS AND
REDUCE WATER DEMAND.
THE WEST: EASTERN MONTANA IS BEGINNING TO SHOW SIGNS OF EARLY
DROUGHT, SIMILAR TO THAT OF WESTERN NORTH DAKOTA, AND THIS
IS REFLECTED IN AN EXPANSION OF D0 OVER SHERIDAN COUNTY.
PRECIPITATION THIS SUMMER HAS BEEN LACKING IN THIS AREA.
IN WESTERN MONTANA, DROUGHT CONDITIONS ARE IMPROVING AND
MODERATE DROUGHT IS NO LONGER DEPICTED IN SANDERS AND LINCOLN
COUNTIES, IN THE KOOTENAI NATIONAL FOREST AREA.
SOUTH CENTRAL COLORADO IS BEGINNING TO EXHIBIT SIGNS OF EARLY
DROUGHT, INCLUDING LACK OF PRECIPITATION THE LAST MONTH DUE TO A
WEAK TO MODERATE MONSOON SEASON, AND WILDFIRE RISK AND ACTIVITY
HAS INCREASED.D0, ABNORMALLY DRY, DESIGNATION WAS INTRODUCED.
AN EVALUATION OF THE SUMMER SEASON SO FAR LED TO A REDUCTION
OF THE AREA OF SEVERE DROUGHT IN NORTHEASTERN CALIFORNIA AND
PARTS OF NORTHWESTERN NEVADA THIS WEEK. D2 IS NOW LIMITED TO A
PORTION OF EASTERN LASSEN COUNTY IN CALIFORNIA, CENTRAL WASHOE
AND WESTERN PERSHING COUNTY IN NEVADA.THIS REASSESSMENT IS A
CULMINATION OF SEVERAL FACTORS, INCLUDING: A MUCH ABOVE NORMAL
AND NEAR-RECORD MONTH OF PRECIPITATION IN JUNE; STREAMFLOW IN
THE REGION IS NEAR NORMAL IN MANY AREAS; RESERVOIRS IN THE AREA
ARE NEAR 80 PERCENT OF NORMAL LEVELS; BENEFICIAL THUNDERSTORMS
HAVE BROUGHT MODEST PRECIPITATION IN JULY; AND COOLER THAN
NORMAL TEMPERATURES IN EARLY AUGUST HAVE REDUCED WATER DEMAND.
WILDLAND FIRE RISK CONTINUES TO BE AN ISSUE IN THIS REGION,
AS WELL AS THE LONG-TERM THREE-YEAR DROUGHT, SO NO CHANGE IN
THE AREA OF MODERATE DROUGHT WAS MADE.
HAWAII, ALASKA AND PUERTO RICO: CENTRAL ALASKA STREAMFLOW DATA
SHOW BELOW NORMAL LEVELS FOR THIS TIME OF YEAR. IN ADDITION,
PRECIPITATION DEFICITS HAVE BEEN ACCUMULATING SINCE THE
WATER YEAR BEGAN LAST FALL, DESPITE ABOVE NORMAL SNOWPACK IN
AND AROUND FAIRBANKS. AS A RESULT, ABNORMALLY DRY /D0/ WAS
EXPANDED NORTHWARD TO INDICATE DRYING CONDITIONS IN THIS REGION.
AS TROPICAL STORM FELICIA MADE ITS WAY TOWARDS HAWAII,
NO SIGNIFICANT IMPROVEMENTS WERE MADE IN THE PRECIPITATION
DEFICIT OR DROUGHT IMPACTS AS OF TUESDAY MORNING. AS A RESULT,
NO CHANGE IN DROUGHT EXTENT OR SEVERITY WAS MADE.
PUERTO RICO REMAINS UNCHANGED AND DROUGHT FREE THIS WEEK.
LOOKING AHEAD:FOR THE FIRST FEW DAYS OF THE NEXT US DROUGHT
MONITOR PERIOD, MONSOONAL MOISTURE WILL CONTINUE IN THE
SOUTHWEST. A SLOW MOVING FRONT APPEARS TO BE MAKING ITS WAY
ACROSS THE NORTHERN STATES, AND ANOTHER FRONT IS STRETCHING
ALONG THE EASTERN SEABOARD. SOME EXISTING DROUGHT AREAS IN
MONTANA AND NORTH DAKOTA MAY BENEFIT FROM SOME PRECIPITATION AS
THE NORTHERN FRONT STALLS OVER THAT REGION. IF THE FORECAST
VERIFIES, EASTERN PARTS OF NORTH CAROLINA AND VIRGINIA MAY
ALSO SEE DRY CONDITIONS IMPROVING. OVER THE NEXT TWO DAYS,
A LOW PRESSURE SYSTEM OFF THE WEST COAST OF ALASKA WILL BECOME
MORE DEVELOPED, BRINGING SOME RAIN TO THE WESTERN PART OF
THE STATE. ANOTHER SMALL AREA OF PRECIPITATION IS FORECAST
ALONG THE CANADIAN BORDER TO THE EAST AS WELL.THE SIX TO TEN
DAY FORECAST /AUGUST 18-22/ CALLS FOR A RIDGE TO SETTLE IN THE
WESTERN CONTINENTAL US, WITH A TROUGH TO THE EAST. THIS WOULD
BRING ABOVE NORMAL TEMPERATURES TO THE WEST AND BELOW NORMAL
TEMPERATURES OVER THE GREAT LAKES AND CENTRAL PLAINS STATES.
SOUTHERN TEXAS AND FLORIDA ARE PROJECTED TO CONTINUE THE
HOT AND DRY TREND FROM LAST WEEK. BELOW NORMAL PRECIPITATION
ACROSS THE NORTHERN TIER STATES IS ALSO REFLECTED IN THE SIX TO
TEN DAY FORECAST. AN AREA OF ABOVE NORMAL PRECIPITATION FOR
THIS PERIOD EXTENDS FROM OKLAHOMA TO THE NORTHEAST. AUTHOR:
LAURA EDWARDS, WESTERN REGIONAL CLIMATE 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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