856
FXUS01 KWBC 181949
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
349 PM EDT THU SEP 18 2008
VALID 00Z FRI SEP 19 2008 - 12Z SAT SEP 20 2008
THE RELATIVELY QUIET PATTEN IN PLACE OVER THE LOWER 48 IS EXPECTED
TO CONTINUE INTO THE WEEKEND. A QUASI-STATIONARY FRONT EXTENDING
FROM THE WESTERN ATLANTIC... ACROSS THE FLORIDA PENINSULA AND
ACROSS THE GULF OF MEXICO WILL PERSIST THROUGH SATURDAY... KEEPING
MOST LOCATIONS ACROSS THE SOUTHERN U.S. IN LOW HUMIDITY. THE
EXCEPTION WILL BE OVER THE LOWER MISSISSIPPI VALLEY WHERE LOW
LEVEL EAST TO SOUTHEASTERLY FLOW WILL COMBINE WITH A WEAK UPPER
LEVEL TROUGH MOVING EAST FROM TEXAS TODAY. THIS IS EXPECTED TO
LEAD TO LIGHT SCATTERED SHOWERS AND MAYBE A THUNDERSTORM OVER THE
LOWER MISSISSIPPI VALLEY TONIGHT INTO EARLY FRIDAY. INCREASING
MOISTURE ACROSS THE AREA ON FRIDAY INTO SATURDAY COULD LEAD TO
PRECIPITATION BECOMING MORE WIDESPREAD IN NATURE WITH HIGHER
RAINFALL TOTALS... ESPECIALLY OVER SOUTHEASTERN LOUISIANA.
A REINFORCING SHOT OF COOL AIR BEHIND A COLD FRONT WILL SETTLE
INTO THE MID ATLANTIC REGION TONIGHT AS AN AREA OF HIGH PRESSURE
MOVES EAST FROM THE GREAT LAKES TO THE WESTERN ATLANTIC OVER THE
NEXT COUPLE OF DAYS. RIDGING WILL REMAIN ANCHORED DOWN THE EAST
COAST TO THE CAROLINAS AND INTO THE CENTRAL U.S. KEEPING
TEMPERATURES AT THESE LOCATIONS AT... TO SOMEWHAT BELOW... AVERAGE
FOR MID SEPTEMBER.
OUT ACROSS THE NORTHERN U.S.... WEST OF THE GREAT LAKES... HIGH
TEMPERATURES OF 10 TO 20 DEGREES ABOVE AVERAGE WILL BEGIN TO COOL
AS TWO SYSTEMS AFFECT THE AREA. ONE WILL BE IN THE FORM OF A
STRONG COLD FRONT DROPPING SOUTH FROM CENTRAL CANADA... EXPECTED
TO REACH THE NORTH CENTRAL U.S. TOMORROW WHILE THE WESTERN PORTION
BECOMES STATIONARY OVER ALBERTA. THE SECOND SYSTEM WILL COME IN
THE FORM OF AN UPPER LEVEL LOW... CURRENTLY OVER THE EASTERN
PACIFIC WHICH WILL REACH THE WEST COAST EARLY FRIDAY... AND MOVE
INTO THE GREAT BASIN FOR SATURDAY. THIS SYSTEM WILL BRING CLOUDS
ALONG WITH SHOWERS AND THUNDERSTORMS TO THE NORTHWEST WHICH WILL
HELP TO COOL TEMPERATURES MUCH CLOSER TO AVERAGE. A WEAK COLD
FRONT WILL ALSO PUSH ONSHORE AHEAD OF THIS UPPER LEVEL LOW.
THE REST OF THE LOWER 48 CAN EXPECT TO SEE VERY LITTLE CHANGE IN
THE WEATHER THROUGH SATURDAY.
OTTO
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