Prognostic Meteorological Discussion
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000
FXUS02 KWBC 161547
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1147 AM EDT TUE SEP 16 2014

VALID 12Z FRI SEP 19 2014 - 12Z TUE SEP 23 2014

...HEAVY RAIN THREAT TO PUSH INTO THE CENTRAL/SOUTHERN PLAINS
LATER THIS WEEK...


...OVERVIEW...

WITH TROUGHING STILL FAVORED SOUTH OF ALASKA BETWEEN 140-170W...
DOWNSTREAM RIDGE/TROUGH PATTERN SHOULD PERSIST AND SLOWLY PUSH
EAST FROM THE PAC NW/EASTERN THIRD OF THE CONUS... RESPECTIVELY.
THIS WILL CARRY A SFC FRONT OUT OF THE PLAINS LATE THIS WEEK AND
TO THE EASTERN/GULF COASTS BY EARLY NEXT WEEK. THE REMNANTS OF
ODILE SHOULD EXIT NORTHERN NEW MEXICO FRI/D3 -- MAINTAINING ITS
500MB VORT MAX THROUGH THEN -- AND BECOME ABSORBED BY THE FRONT
OVER THE CENTRAL PLAINS THEREAFTER. AS THE RIDGE AXIS BEGRUDGINGLY
MOVES EAST OF THE DIVIDE BY THE END OF THE PERIOD A COLD FRONT
SHOULD PUSH INTO THE PAC NW BUT WITH THE BULK OF ITS AFFECTS
CONSTRAINED TO CANADA.


...GUIDANCE EVALUATION/PREFERENCES...

THE 00Z GEFS/ECMWF ENSEMBLES SHOW GOOD AGREEMENT THROUGH THE
PERIOD WITH A TENDENCY TOWARD A BUT MORE AMPLIFICATION BY NEXT
WEEK COMPARED TO EARLIER CYCLES. BOTH THE 00Z ECMWF AND GFS LIED
ON THE MORE AMPLIFIED SIDE OF THE ENSEMBLE SPREAD ESPECIALLY OVER
SOUTHERN CANADA WHILE THE 00Z GEFS/ECENS MEANS WERE MORE MODEST
BUT OFFERED MUCH MORE CONSISTENCY WITH THE ONGOING WPC FORECAST.
USED A NEARLY EVEN BLEND OF THE 00Z ENSEMBLE GUIDANCE WITH THE
OVERNIGHT WPC FORECAST.


...SENSIBLE WEATHER HIGHLIGHTS...

HEAVY PRECIP THREAT SHOULD PROGRESS NORTHEASTWARD OUT OF NEW
MEXICO INTO THE SOUTHERN PLAINS LATE THIS WEEK AS THE REMNANT
MID-LEVEL CIRCULATION INTERACTS WITH INCREASING MOISTURE PUSHING
NORTHWARD THROUGH TEXAS THIS WEEKEND. MODELS  MAY NOT BE HANDLING
THIS EVOLUTION WELL AT THIS LEAD TIME... THOUGH AT LEAST THE 00Z
GFS SHOWS A SWATH OF 2-4 INCHES OF PRECIP FROM THE TX PANHANDLE
TOWARD CHICAGO /PERHAPS AT THE EXPENSE OF CENTRAL TEXAS/. TO THE
NORTH... THE MODELS/ENSEMBLES HIGHLIGHT THE WESTERN LAKES AS LOW
PRESSURE MOVES INTO SOUTHERN CENTRAL ONTARIO. DISSIPATING SFC
FRONT OVER FLORIDA WILL ALSO ACT AS A FOCUS FOR ENHANCED PRECIP
OVER THE SUNSHINE STATE THIS WEEKEND BEFORE IT FADES AWAY. BY
EARLY NEXT WEEK... MORE WIDESPREAD BUT LIGHTER PRECIP IS EXPECTED
ALONG AND AHEAD OF THE PROGRESSIVE FRONTAL BOUNDARY IN THE EAST
WITH HIGH PRESSURE MOVING INTO THE GREAT LAKES. TEMPERATURES
SHOULD BE MOSTLY WARMER THAN AVERAGE IN THE WEST AND COOLER THAN
AVERAGE IN THE EAST... MODULATED BY THE COLD FRONT PROGRESSION.


FRACASSO

$$




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