SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
455 PM EDT TUE MAY 05 2009
 
VALID 00Z WED MAY 06 2009 - 12Z THU MAY 07 2009
 
THE QUASI-STATIONARY FRONT WHICH HAS BEEN THE FOCUS FOR WIDESPREAD
RAIN AND THUNDERSTORMS FROM THE SOUTHERN STATES THROUGH MUCH OF
THE EAST OVER THE PAST FEW DAYS IS FORECAST TO APPRECIABLY MOVE...
STARTING TOMORROW. THIS WILL HAPPEN AS A SURFACE LOW DEVELOPS
ALONG THE FRONT OVER THE MIDDLE MISSISSIPPI VALLEY IN RESPONSE TO
THE APPROACH OF AN UPPER LEVEL TROUGH FROM THE WEST. THE SURFACE
LOW WILL FOLLOW A SIMILAR PATH TO THE UPPER LEVEL TROUGH... WHICH
IS CURRENTLY PUSHING INTO KANSAS AND OKLAHOMA. THE UPPER TROUGH
AND SURFACE LOW WILL TRACK THROUGH THE LOWER OHIO VALLEY TOMORROW
AND THROUGH THE NORTHEAST ON THURSDAY... DRAGGING A WEAKENED COLD
FRONT ALONG THE WAY.

AN AREA OF CONVECTION IS ONGOING THIS AFTERNOON OVER KANSAS AND
OKLAHOMA JUST AHEAD OF THE UPPER WAVE... AND IS EXPECTED TO TRACK
NORTHEASTWARD INTO THURSDAY. ADDITIONAL CONVECTIVE DEVELOPMENT IS
EXPECTED LATE TONIGHT OVER EAST TEXAS... AND WILL SPREAD EASTWARD
THROUGH THE GULF COAST STATES DURING THE DAY ON WEDNESDAY.
NUMEROUS FLOOD WATCHES AND WARNINGS ARE IN EFFECT THIS AFTERNOON
FROM EAST TEXAS AND OKLAHOMA... NORTHEASTWARD INTO THE NORTHERN
MID ATLANTIC REGION DUE TO RAINFALL WHICH HAS ALREADY OCCURRED...
COUPLED WITH THE EXPECTED RAINFALL TONIGHT INTO THURSDAY. TWO DAY
RAINFALL TOTALS COULD EXCEED AN INCH IN MANY LOCATIONS ACROSS THE
AREAS MENTIONED ABOVE.

LOOKING NORTHWESTWARD... A WEAK PACIFIC FRONT WILL DISSIPATE EARLY
THIS EVENING OVER THE NORTHERN PLAINS AS ANOTHER PACIFIC FRONT
EMERGES ACROSS THE REGION TONIGHT. RAINFALL WITH THESE SYSTEMS
SHOULD STAY ON THE LIGHT SIDE... EXCEPT ACROSS FAVORED MOUNTAINOUS
UPSLOPE AREAS AND BENEATH ANY THUNDERSTORMS THAT DEVELOP. IN
ADDITION TO A CONTINUED MOIST ONSHORE PACIFIC FLOW ACROSS THE
NORTHWESTERN QUADRANT OF THE COUNTRY... THE CENTER OF A CLOSED
UPPER LEVEL LOW JUST WEST OF BRITISH COLUMBIA WILL BEGIN TO SLIDE
EASTWARD WEDNESDAY NIGHT INTO THURSDAY WHICH WILL BRING IN
SLIGHTLY COOLER AIR... HOWEVER PRECIPITATION WILL BEGIN TO TAPER
OFF BY THURSDAY EVENING AS HIGH PRESSURE WORKS ITS WAY IN.

OTTO


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