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Extended Forecast Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1538Z Aug 21, 2014)
 
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Abbreviations and acronyms used in this product
 
Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1138 AM EDT THU AUG 21 2014

VALID 12Z SUN AUG 24 2014 - 12Z THU AUG 28 2014

...FLOW PATTERN/WEATHER HIGHLIGHTS AND GUIDANCE/UNCERTAINTY
ASSESSMENT...

THE WPC MEDIUM RANGE PRODUCT SUITE HAS BEEN PRIMARILY DERIVED FROM
A 50-50 BLEND OF COMPATABLE GUIDANCE FROM THE 06 UTC GFS ENSEMBLE
MEAN AND 00 UTC ECMWF ENSEMBLE MEAN. FORECAST SPREAD AND
UNCERTAINTY REMAINS SLIGHTLY ABOVE NORMAL OVERALL CONSIDERING
RECENT RUN TO RUN MODEL CONTINUITY ISSUES INCLUDING AN UNCERTAIN
TROPICAL SYSTEM INFLUENCE. THIS LENDS AN ENSEMBLE MEAN APPROACH.

HIGHLY AMPLIFIED AND COOLING MID-UPPEL LEVEL TROUGHING OVER THE
WRN US EJECTS NEWD INTO S-CENTRAL CANADA AND THE N-CENTRAL US FROM
THE WEEKEND INTO EARLY NEXT WEEK. ASSOCIATED LEAD SURFACE
LOW/FRONTAL SYSTEM WILL FOCUS POTENTIAL FOR CONVECTION/RAINFALL AS
ENHANCED BY SOME CONNECTION WITH LINGERING SWRN US/ROCKIES
MONSOONAL PCPN/MOISTURE. THIS OCCURS AS UPSTREAM KICKER IMPULSE
ENERGIES DIG BACK INTO THE WRN US. TROUGH ENERGY SHOULD
SUBSEQUENTLY WORK GRADUALLY INTO THE S-CENTRAL CANADA AND THE
CENTRAL US EARLY IN THE WEEK. EXPECT MORE UNSETTLED WEATHER
INCLUDING ANOTHER LEAD ROUND OF ACTIVE CONVECTION THROUGH MID NEXT
WEEK AS ENERGY BUMPS INTO AND RUNS OVERTOP FROM THE CENTRAL US
THROUGH THE MIDWEST THEN NORTHEAST OVERTOP A VERY HOT/AMPLIFIED
E-CENTRAL US MID-UPPER LEVEL RIDGE. A DOWNSTREAM AMPLIFIED LEAD
MID-UPPER LEVEL TROUGH HELD DOWN OFF THE NERN US MAY PROVE SLOW TO
DISLODGE THROUGH EARLY NEXT WEEK TO THE LEE OF THE E-CENTRAL US
RIDGE. THIS WOULD ALLOW ASSOCIATED ERN US HIGH PRESSURE
DAMMING/COOLING TO THE LEE OF THE APPALACHIANS TO LINGER ALONG
WITH A TRAILING LEAD FRONT/CONVECTION WELL DOWN INTO THE SERN US
FOR SUMMER...BUT THAT HAS BEEN OFTEN THE CASE THIS YEAR.
MEANWHILE...THE PACIFIC AND ATLANTIC BASIN TROPICS REMAIN
CERTAINLY MUCH MORE ACTIVE NOW AND WILL CONTINUED TO BE MONITORED
BY THE NATIONAL HURRICANE CENTER. AN AREA OF CONVECTION NOW
APPROACHING THE LEEWARD CARIBBEAN ISLANDS IS OF PARTICULAR
INTEREST WITH A RECON FLIGHT SCHEDULED.

SCHICHTEL