558
FXUS01 KWBC 030848
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
447 AM EDT FRI OCT 03 2008
VALID 12Z FRI OCT 03 2008 - 00Z SUN OCT 05 2008
OVER THE WESTERN CONUS... A LARGE UPPER LEVEL TROUGH IS EXPECTED
TO MOVE INTO THE REGION DURING THE SHORT RANGE PERIOD. ASIDE FROM
BELOW NORMAL TEMPERATURES... EXPECT STEADY AND SIGNIFICANT RAIN TO
MOVE INTO WESTERN WASHINGTON... DOWN TO NORTHERN CALIFORNIA
STARTING DURING THE AFTERNOON AND EVENING HOURS TODAY. STRONG
WINDS ARE EXPECTED TO IMPACT REGIONS OF HIGHER TERRAIN OUT WEST AS
THE STORM MOVES ONSHORE. ALSO... THE SIERRA NEVADA MOUNTAIN RANGE
WILL SEE SIGNIFICANT SNOW AND STRONG WINDS ABOVE 8000 TO 10000
FT... HOWEVER ONLY RAIN IS EXPECTED BELOW ABOUT 7000 FT. WEST
FACING SLOPES OF THE MAJOR MOUNTAIN RANGES ACROSS THE WEST ARE
EXPECTED TO SEE THE HIGHEST RAINFALL TOTALS THROUGH SATURDAY. SNOW
COULD START TO MIX IN AROUND ELEVATIONS OF 8000 FT ACROSS UTAH AND
COLORADO.
OUT EAST... A SECONDARY COLD FRONT WILL WEAKEN AS IT CONTINUES TO
MOVE THROUGH THE NORTHEAST AND MID ATLANTIC REGION TODAY. COLD AIR
ALOFT... RELATIVE TO WATER TEMPERATURES IN THE 60S ACROSS THE
CENTRAL AND EASTERN GREAT LAKES... WILL GENERATE LOW LEVEL
INSTABILITY AND LAKE EFFECT RAIN SHOWERS TO THE EAST OF THE LAKES.
THIS WILL OCCUR MUCH THE SAME WAY LAKE EFFECT SNOW DEVELOPS WITH
LOCALLY INTENSE... NARROW BANDS OF PRECIPITATION... HOWEVER
TEMPERATURES AT THE SURFACE WILL BE TOO WARM FOR SNOW. ALSO...
UPPER LEVEL ENERGY ROTATING AROUND AN UPPER LEVEL TROUGH WILL
CONTINUE TO PRODUCE SCATTERED SHOWERS OVER MOST OF THE NORTHEAST
TODAY... BEFORE EXITING INTO EASTERN CANADA THIS EVENING. HIGH
PRESSURE IS EXPECTED TO BUILD IN OVER THE LAKES FOR SATURDAY WHICH
SHOULD REDUCE COVERAGE OF SHOWERS IN THE LEE OF THE LAKES. HIGH
TEMPERATURES OVER THE NORTHEAST AND MID ATLANTIC WILL GENERALLY BE
IN THE 50S AND 60S HEADING INTO THIS WEEKEND WITH 70S FARTHER
SOUTH INTO THE MID ATLANTIC REGION UNDER PARTLY CLOUDY SKIES.
A NEARLY STATIONARY FRONT ACROSS SOUTHERN FLORIDA WILL KEEP
SHOWERS AND THUNDERSTORMS IN THE FORECAST FROM FRIDAY NIGHT
THROUGH SATURDAY AS HIGH LEVELS OF ATMOSPHERIC MOISTURE POOL ALONG
AND SOUTH OF THE BOUNDARY. LOW LEVEL EASTERLY FLOW WILL COMBINE
WITH UPPER LEVEL ENERGY TO DEVELOP SHOWERS AND THUNDERSTORMS OVER
THE SOUTHERN PORTION OF THE STATE BEGINNING TONIGHT.
OTTO
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