Valid Sunday, May 27, 2012 to Thursday, June 07, 2012

Summary of Forecasts and Hazards

US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EDT MAY 24 2012

SYNOPSIS: A SURFACE LOW PRESSURE SYSTEM IS FORECAST TO TRACK FROM THE CENTRAL PLAINS TO SOUTHEAST CANADA, WHILE A TRAILING COLD FRONT ADVANCES FROM THE GREAT PLAINS TO THE EASTERN U.S. DURING THE MEMORIAL DAY WEEKEND, A HOT, HUMID AIR MASS IS FORECAST TO AFFECT AREAS FROM THE MIDDLE MISSISSIPPI RIVER TO THE EAST COAST. AN UPPER-LEVEL RIDGE OF HIGH PRESSURE OVER THE EAST-CENTRAL U.S. IS FORECAST TO WEAKEN NEXT WEEK. A LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP NEAR THE SOUTHEAST COAST AND THEN TRACK WEST ACROSS NORTHERN FLORIDA. A BROAD AREA OF LOW PRESSURE IS FORECAST TO PERSIST ACROSS ALASKA.

HAZARDS

• MUCH ABOVE NORMAL TEMPERATURES FROM THE MIDDLE MISSISSIPPI VALLEY EASTWARD ACROSS THE OHIO/TENNESSEE VALLEYS, AND MID-ATLANTIC, MAY 27-28.
• RIVER FLOODING POSSIBLE FOR PARTS OF MINNESOTA, MAY 27-28.
• SEVERE WEATHER FOR PARTS OF THE NORTHERN/CENTRAL PLAINS, MAY 27 AND UPPER MISSISSIPPI VALLEY/GREAT LAKES, MAY 28.
• HIGH WINDS FOR THE COASTAL WATERS OF THE CAROLINAS, GEORGIA, AND NORTHEAST FLORIDA, MAY 27-28.
• HEAVY RAIN FOR SOUTHEAST GEORGIA AND NORTHEAST FLORIDA, MAY 27-29.
• SEVERE DROUGHT FOR PARTS OF THE SOUTHEAST, LOWER OHIO VALLEY, CENTRAL ROCKIES, SOUTHERN PLAINS, SOUTHWEST, INTERIOR PORTIONS OF CALIFORNIA, THE GREAT BASIN, AND HAWAII.

DETAILED SUMMARY

FOR SUNDAY MAY 27 - THURSDAY MAY 31: AN AMPLIFIED SUBTROPICAL RIDGE IS EXPECTED TO RESULT IN MUCH ABOVE NORMAL TEMPERATURES (MORE THAN 12 DEGREES F) ACROSS MUCH OF THE EAST-CENTRAL CONUS THROUGH MEMORIAL DAY. MAXIMUM TEMPERATURES MAY EXCEED 90 DEGREES F FOR MULTIPLE DAYS ACROSS THE OHIO VALLEY AND MID-ATLANTIC. HEAT INDEX VALUES ARE FORECAST TO BE QUITE HIGH (ABOVE 100F) FOR LATE MAY ACROSS PARTS OF THE AREA OUTLINED FOR MUCH ABOVE NORMAL TEMPERATURES. NEXT WEEK, A TROUGH IS EXPECTED TO DEVELOP OVER THE EAST-CENTRAL CONUS WITH MUCH COOLER TEMPERATURES. FROST AND/OR LIGHT FREEZES MAY OCCUR IN THE UPPER MISSISSIPPI VALLEY ON WEDNESDAY AND THURSDAY MORNINGS.

MODEL GUIDANCE REMAINS CONSISTENT AND IS IN GOOD AGREEMENT THAT A VIGOROUS SHORTWAVE TROUGH WILL ADVANCE ACROSS THE NORTH-CENTRAL CONUS. SEVERE THUNDERSTORMS WITH LOCALLY HEAVY RAIN ARE EXPECTED ON SUNDAY AND MONDAY ALONG AN EASTWARD ADVANCING COLD FRONT ACROSS THE NORTHERN/CENTRAL PLAINS, UPPER MISSISSIPPI VALLEY, AND GREAT LAKES. INCREASED RUNOFF IS EXPECTED TO RESULT IN RIVER RISES ACROSS MINNESOTA WITH MINOR FLOODING FORECAST ALONG THE MISSISSIPPI RIVER IN AITKIN AND NEAR FORT RIPLEY.

AFTER AN AMPLIFIED UPPER-LEVEL TROUGH SHIFTS EAST, CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TO EASE ACROSS THE SOUTHWEST U.S. BY EARLY NEXT WEEK. CURRENTLY, LARGE WILDFIRES RESIDE IN CENTRAL ARIZONA WITH MORE THAN 16,000 ACRES BURNED IN MARICOPA AND YAVAPAI COUNTIES.

AS OF THURSDAY AFTERNOON, AN ELONGATED AREA OF LOW PRESSURE EXISTS ACROSS THE NORTHWEST CARIBBEAN SEA. MODEL AGREEMENT HAS IMPROVED SINCE YESTERDAY AND OPERATIONAL MODELS INDICATE LOW PRESSURE SYSTEM DEVELOPMENT OFFSHORE OF THE SOUTHEAST COAST PRIOR TO THIS PERIOD. THE EXACT TRACK AND STRENGTH OF THE SURFACE LOW VARIES AMONG MODELS, BUT IT IS EXPECTED TO DRIFT INLAND INTO NORTHEAST FLORIDA BY MONDAY MORNING. HEAVY RAIN IS FORECAST TO ACCOMPANY THIS AREA OF LOW PRESSURE AND IS MOST LIKELY ACROSS SOUTHEAST GEORGIA AND NORTHEAST FLORIDA, WHILE HIGH WINDS CAN BE EXPECTED FOR THE COASTAL WATERS OF THE SOUTHEAST. AN ELEVATED RISK OF RIP CURRENTS CAN BE EXPECTED FOR THE BEACHES ALONG THE SOUTHEAST COAST DURING THE HOLIDAY WEEKEND. SINCE THIS LOW PRESSURE SYSTEM COULD ACQUIRE TROPICAL CHARACTERISTICS, PLEASE REFER TO THE LATEST STATEMENTS FROM THE NATIONAL HURRICANE CENTER AT: HTTP://WWW.NHC.NOAA.GOV/.

FOR FRIDAY JUNE 01 - THURSDAY JUNE 07: THE 0Z GFS AND 0Z ECMWF ENSEMBLE MEANS DEPICT A WEAK RIDGE OVER THE WEST-CENTRAL CONUS AND A BROAD TROUGH DEVELOPING ACROSS THE EASTERN CONUS. NO SPECIFIC HAZARDS ARE INDICATED ON THE MAP FOR THE WEEK 2 PERIOD EXCEPT FOR THE SEVERE DROUGHT AREAS.

ACCORDING TO THE U.S. DROUGHT MONITOR, SEVERE DROUGHT HAS RAPIDLY DEVELOPED IN WESTERN KENTUCKY AND SOUTHEAST MISSOURI WITH A LARGE EXPANSION OF ABNORMAL DRYNESS ACROSS THE CENTRAL PLAINS AND PARTS OF THE CORN BELT. THE FLASH DROUGHT CONDITIONS ARE DUE TO SHORT-TERM DRYNESS ACCOMPANIED BY ABOVE NORMAL TEMPERATURES.

FORECASTER: BRAD PUGH

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