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Extended Forecast Discussion
 
(Caution: Version displayed is not the latest version. - Issued 0501Z Jul 27, 2014)
 
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Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
101 AM EDT SUN JUL 27 2014

VALID 12Z WED JUL 30 2014 - 12Z SUN AUG 03 2014

...OVERVIEW...

THE EVER-FAMILIAR LONGWAVE RIDGE/TROUGH PATTERN ACROSS THE CONUS
SHOWS NO SIGN OF CHANGING AS WE TURN THE CALENDAR TO AUGUST IN THE
MEDIUM RANGE. THOUGH THE UPSTREAM TROUGHING OVER THE GULF OF
ALASKA AND DOWNSTREAM RIDGING OVER SW CANADA MAY FADE DURING THE
PERIOD... RIDGING OVER THE NW ATLANTIC WILL MAINTAIN ITSELF NEAR
NEWFOUNDLAND... WHICH WILL NUDGE THE TROUGH AXIS WESTWARD BY NEXT
WEEKEND FROM AROUND 80W TO NEAR 90W. THIS SHOULD KEEP JUST ONE
MAIN SFC BOUNDARY ALONG OR JUST OFFSHORE THE GULF AND EAST
COASTS... IMPRESSIVELY FAR SOUTH FOR EARLY AUGUST.

...GUIDANCE PREFERENCES...

THE 18Z GFS/GEFS MEAN AND 12Z ECMWF/ECENS MEAN ALL CLUSTER CLOSE
TOGETHER THROUGH SUN/D7... THOUGH WITH EXPECTED DETAIL
DIFFERENCES. TRENDED FROM A 50/50 GFS/ECMWF BLEND TOWARD MORE
ENSEMBLE MEAN WEIGHTING BY DAYS 6-7. WITH SUCH RELATIVELY LOW
SPREAD... HARD TO ARGUE AGAINST THIS FAB FOUR.

...SENSIBLE WEATHER HIGHLIGHTS...

DEEP TROUGHING WILL RESULT IN TEMPERATURES 10-20F BELOW AVERAGE
EAST OF THE ROCKIES... CENTERED OVER THE SOUTHERN PLAINS ON THE
RELATIVELY COOL/RAINY SIDE OF THE POLAR FRONT. THIS AREA SHOULD
ALSO SEE THE BRUNT OF THE RAINFALL THIS PERIOD AIDED BY CONVECTION
EXITING CO AND PUSHING SOUTHEASTWARD THROUGH OK/TX WED-THU. TO THE
EAST... THE FRONT WILL GET HUNG UP OFFSHORE THE EAST COAST AND
EVENTUALLY GET PUSHED BACK WESTWARD AS RIDGING IN THE NW ATLANTIC
NUDGES IT TOWARD THE COAST. RAINFALL SHOULD FOCUS OVER MUCH OF
FLORIDA AND THE UP THE GA/SC/NC COASTS AND THEN INTO THE
MID-ATLANTIC AND NEW ENGLAND BY THE END OF NEXT WEEKEND... THOUGH
IT IS HERE WHERE THE MODELS/ENSEMBLES VARY ON HOW FAR WEST TO PUSH
THE FRONT AND ALSO THE PRECIP. REGARDLESS... HUMIDITY WILL SLOWLY
BE ON THE RISE IN THE I-95 CORRIDOR THROUGH THE PERIOD AFTER A FEW
REFRESHING/DRY DAYS. THE WEST WILL STAY WARM/HOT WITH TEMPERATURES
WELL INTO THE 90S IN THE INTERIOR PAC NW. MONSOONAL MOISTURE AND
SOME CLOUDINESS SHOULD SHAVE A FEW DEGREES OFF TEMPERATURES IN THE
DESERT SW. IN BETWEEN...  HIGH-BASED THUNDERSTORMS MAY AGGRAVATE
THE FIRE WEATHER THREAT.


FRACASSO