SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
436 AM EDT TUE MAY 13 2008
 
VALID 12Z TUE MAY 13 2008 - 00Z THU MAY 15 2008
 
THE BASE OF A STRONG UPPER LEVEL TROUGH WILL SEPARATE FROM THE
MAIN FLOW AND HEAD ACROSS ARIZONA AND NEW MEXICO TODAY...REACHING
WEST TEXAS BY WEDNESDAY. COLD TEMPERATURES BENEATH THE UPPER
TROUGH ARE FORECAST TO ALLOW SNOW TO MIX IN WITH PRECIPITATION
BEHIND A COLD FRONT ACROSS PORTIONS OF NORTH CENTRAL
ARIZONA...THOUGH ACCUMULATIONS SHOULD BE MINIMAL IF ANY. SNOW
ACCUMULATIONS ARE EXPECTED TO BE MORE NOTEWORTHY ACROSS CENTRAL
COLORADO AS STRONG VERTICAL MOTIONS SET UP OVER THE AREA TODAY IN
ASSOCIATION WITH THE UPPER TROUGH. PRECIPITATION ACROSS THE
SOUTHWEST WILL BEGIN TO SUBSIDE LATE TONIGHT AS A STRONG RIDGE OF
HIGH PRESSURE BUILDS INTO THE WEST. 

PRECIPITATION ACROSS THE NORTHWESTERN U.S. IS EXPECTED TO INCREASE
BY THIS EVENING IN ADVANCE OF A PACIFIC SYSTEM WHICH IS FORECAST
TO MAKE LANDFALL AND DISSIPATE ACROSS BRITISH COLUMBIA EARLY
TODAY. THE BULK OF THE STEADIER PRECIPITATION SHOULD STAY CONFINED
ALONG CASCADES AND WESTWARD. ANOTHER SYSTEM WILL APPROACH BRITISH
COLUMBIA LATE WEDNESDAY...HOWEVER ONLY SCATTERED RAIN IS FORECAST
ACROSS THE CASCADES WEDNESDAY NIGHT INTO THURSDAY WITH THE REST OF
THE NORTHWEST U.S. STAYING DRY.

FROM THE SOUTHERN PLAINS INTO THE MIDWEST...A MODERATE FETCH OF
LOW LEVEL FLOW OFF THE GULF OF MEXICO WILL ADVECT ABUNDANT LOW
LEVEL MOISTURE INTO THE REGION...GENERATING SUBSTANTIAL
INSTABILITY FROM TEXAS INTO MISSOURI AHEAD OF A COLD FRONT &
DRYLINE FOR TODAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL
DEVELOP THIS AFTERNOON ACROSS EASTERN SECTIONS OF THE PLAINS INTO
THE MISSISSIPPI VALLEY...WITH A SECOND ROUND OF STRONG TO SEVERE
STORMS DEVELOPING BY LATE AFTERNOON AHEAD OF THE COLD FRONT AND
DRYLINE. STORMS ARE FORECAST TO PROGRESS TO THE EAST OVERNIGHT AS
THE COLD FRONT MAKES MORE PROGRESS THROUGH THE REGION. WEDNESDAY
COULD FEATURE MORE SEVERE WEATHER WITHIN SHOWERS AND THUNDERSTORMS
AHEAD OF THE COLD FRONT ACROSS EASTERN PORTIONS OF THE SOUTHERN
PLAINS INTO THE LOWER MISSISSIPPI VALLEY.

THE STRONG NORTHERLY FLOW WHICH KEPT MUCH OF THE MID ATLANTIC AND
NEW ENGLAND REGION WELL BELOW NORMAL ON MONDAY...WILL BEGIN TO
SUBSIDE TODAY AS A STORM SYSTEM OVER THE ATLANTIC MOVES AWAY FROM
LAND. THIS WILL ALLOW FOR MOSTLY CLEAR SKIES TODAY AND HIGH
TEMPERATURES TO RETURN MUCH CLOSER TO NORMAL ACROSS THE REGION.
CLOUDS WILL BE ON THE INCREASE FOR WEDNESDAY ACROSS MUCH OF THE
EAST IN ADVANCE OF AN APPROACHING COLD FRONT...HOWEVER
TEMPERATURES WILL STAY CLOSE TO AVERAGE ACROSS THE ENTIRE EASTERN
THIRD OF THE COUNTY.

OTTO

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