Prognostic Meteorological Discussion
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000
FXUS02 KWBC 201600
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1159 AM EDT WED AUG 20 2014

VALID 12Z SAT AUG 23 2014 - 12Z WED AUG 27 2014

...PATTERN...GUIDANCE/UNCERTAINTY ASSESSMENT...SENSIBLE WEATHER
HIGHLIGHTS...

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 IS PROBABLY SLIGHTLY ABOVE AVERAGE OVERALL CONSIDERING
RECENT RUN TO RUN VARIANCES...LENDING 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 OVER
THE WEEKEND AND 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 MOISTURE. THIS OCCURS AS UPSTREAM KICKER IMPULSE
ENERGIES DIG BACK INTO THE NWRN US AND THIS TROUGHING SHOULD
SUBSEQUENTLY WORK GRADUALLY OUT INTO THE S-CENTRAL CANADA AND THE
N-CENTRAL US WITH MORE UNSETTLED WEATHER INCLUDING ANOTHER LEAD
ROUND OF ACTIVE CONVECTION EARLY AND MID NEXT WEEK AS ENERGY BUMPS
INTO A HOT/AMPLIFIED E-CENTRAL US MID-UPPER LEVEL RIDGE. A
DOWNSTREAM AMPLIFIED MEAN TROUGH POSITION DUG DOWN OFF THE NERN US
MAY ALSO 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 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.
THE TROPICS ARE CERTAINLY MUCH MORE ACTIVE NOW AND WILL CONTINUED
TO BE MONITORED BY THE NATIONAL HURRICANE CENTER.

SCHICHTEL

$$





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