Prognostic Meteorological Discussion
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FXUS02 KWBC 010509
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
109 AM EDT MON SEP 01 2014

VALID 12Z THU SEP 04 2014 - 12Z MON SEP 08 2014

...OVERVIEW AND GUIDANCE PREFERENCES...

UPPER PATTERN SHOULD FEATURE RIDGING IN THE NORTHEAST PACIFIC AND
NORTH-CENTRAL ATLANTIC WITH A PROGRESSIVE UPPER LOW TRACKING
THROUGH NORTHERN CANADA. RIDGING SHOULD BUILD BRIEFLY INTO THE
NORTHEAST/EASTERN GREAT LAKES/MID-ATLANTIC BY THE END OF THE WEEK
BEFORE THE ENERGETIC NORTHERN STREAM ACROSS CANADA DIPS DOWN ONCE
AGAIN INTO THE GREAT LAKES. NE PAC RIDGING WILL SUPPORT A SPLIT
FLOW THAT SHOULD LINGER TROUGHING ALONG 120W. MAIN STICKING POINT
IN THE MODELS CONTINUES TO BE TIMING THE LARGER-SCALE FEATURES.
THE 18Z GFS AND 12Z ECMWF CLUSTERED NEAR THE 12Z ECENS MEAN WHILE
THE 18Z GEFS MEAN APPEARED TO BE A QUICK OUTLIER WITH THE FLOW
ALONG THE US/CANADIAN BORDER. BY THIS COMING WEEKEND... THE GFS
BEGAN TO OUTPACE THE ECMWF/ECENS MEAN. THE OVERALL TREND HAS BEEN
A BIT SLOWER WITH THE FRONTAL PROGRESSION THROUGH THE NORTHEAST SO
OPTED TO LEAN TOWARD THE ECMWF/ECENS MEAN BY SUN/D6 AND THEN JUST
THE EC MEAN FOR MON/D7 MOSTLY DUE TO THE DIFFERENCES OVER AND JUST
UPSTREAM FROM THE PAC NW /ECMWF APPEARS WAY OVERDONE WITH ITS
APPROACHING DEEP UPPER LOW/.


...SENSIBLE WEATHER HIGHLIGHTS...

MAIN PLAYER WILL BE THE FRONTAL BOUNDARY INITIALLY IN THE CENTRAL
PLAINS AND UPPER MIDWEST THU/D4. MILDER TEMPERATURES AHEAD OF THE
COLD FRONT... ABOUT +5 TO +15F... WILL BE REPLACED BY COOLER
TEMPERATURES OF SIMILAR DEPARTURES BUT CONCENTRATED IN THE CENTRAL
PLAINS DUE TO CLOUDY/SHOWERY CONDITIONS POST-FROPA. THE
NORTHEASTERN QUARTER OF THE CONUS WILL FALL BACK TO MORE TYPICAL
SEPTEMBER TEMPERATURES BY SUN-MON NEXT WEEK. PRECIPITATION WILL
ACCOMPANY THE COLD FRONT BUT ALSO SHOULD FALL OVER THE
SOUTHEAST/FLORIDA AND S TX DUE TO SOME ENHANCED TROPICAL MOISTURE.
DEFLECTING UPPER RIDGING OVER INTERIOR TEXAS WILL GRADUALLY GIVE
WAY TO MORE PRECIPITATION BY THE END OF THE PERIOD... NOT TO
MENTION AZ/NM WITH A RENEWED PUSH OF MOISTURE FROM OLD MEXICO.


FRACASSO

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