Preliminary Forecasts
Issued by NWS

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FXUS02 KWNH 020616
PREEPD

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
216 AM EDT TUE SEP 02 2014

VALID 12Z FRI SEP 05 2014 - 12Z TUE SEP 09 2014

...OVERVIEW AND GUIDANCE EVALUATION/PREFERENCES...

INITIAL RIDGING IN THE EASTERN PORTION OF THE CONUS AT THE END OF
THE WEEK WILL RETREAT INTO THE NW ATLANTIC AND THE GULF OF MEXICO
BY NEXT WEEK. A COLD FRONT WILL PUSH THROUGH THE EAST AND INTO THE
SOUTHEAST THROUGH THE PERIOD WHILE ANOTHER COLD FRONT ENTERS THE
PAC NW MON/D6. OFF THE COAST OF MEXICO... A TROPICAL DISTURBANCE
MAY DEVELOP AND MOVE N/NW PARALLEL TO BAJA CALIFORNIA. THE
MODELS/ENSEMBLES REMAIN IN FAIR SYNOPTIC AGREEMENT BUT STILL SHOW
TIMING DIFFERENCES BY SAT/D4 THAT CARRY THROUGH INTO NEXT WEEK.
THE ECENS MEAN HAS BEEN MOST CONSISTENT OF ANY OF THE GUIDANCE
OPTIONS... FOLLOWED BY THE ECMWF AND THEN THE GFS/GEFS MEAN. OPTED
TO USE A MAJORITY 12Z/01 ECENS WEIGHTING BALANCED BY THE SLOWER
12Z ECMWF AND QUICKER 18Z GFS WITH THE SYSTEM MOVING THROUGH
SOUTHERN CANADA SAT/D4. IN THE EAST... THE MODELS AGREE ON SIMILAR
TIMING TO THE FROPA THROUGH THE NORTHEAST... BUT DIFFER QUITE
NOTICEABLY IN HOW MUCH TRAILING HIGH PRESSURE CAN KEEP LINGERING
MOISTURE OFFSHORE /GFS WELL TO THE SOUTH... ECMWF MUCH LESS SO BY
MON-TUE/. RECENT GFS RUNS FALL ON THE DEEPEST SIDE OF THE ENSEMBLE
SPREAD ON MON/D6 WITH LOWER HEIGHTS INTO NEW ENGLAND SO PUSHING
THE FRONT THAT FAR SOUTH SEEMS LESS LIKELY.


...SENSIBLE WEATHER HIGHLIGHTS...

COLD FRONT WILL BE THE FOCUS FOR SHOWERS/STORMS IN THE
CENTRAL/EASTERN STATES LATE THIS WEEK INTO THE WEEKEND WITH MORE
SCATTERED STORMS IN THE SOUTHEAST. BY NEXT WEEK... LARGE SPREAD IN
THE QPF OVER THE MID-ATLANTIC BUT SHOULD THE FRONT LINGER NEAR THE
NC/SC BORDER THEN THE FOCUS OF HEAVIER RAINFALL SHOULD LIE OVER SE
VA AND NE NC. BY NEXT WEEK THE GUIDANCE SHOW A STRONG SURGE OF
MOISTURE INTO THE SW AHEAD OF ANY DEVELOPING TROPICAL SYSTEM. GEFS
PROBABILITIES OF PW ANOMALIES OF OVER +1 STD DEV EXCEED 70 PERCENT
SUN-TUE OVER SOUTHERN/CENTRAL ARIZONA AND EXCEED 50 PERCENT FOR +2
STD DEVIATIONS. EC ENSEMBLES ARE A BIT LESS EMPHATIC... BUT STILL
IMPRESSIVE.


FRACASSO

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