Prognostic Meteorological Discussion
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FXUS02 KWBC 020558
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
158 AM EDT SAT AUG 02 2014

VALID 12Z TUE AUG 05 2014 - 12Z SAT AUG 09 2014

TROPICAL STORM BERTHA WAS LOCATED OVER THE NERN CARIBBEAN NEAR
15.7N 63.0W AT 03 UTC AND IS PACKING 45 KT MAX SUSTAINED WINDS
WITH GUSTS TO 55 KTS. THE NATIONAL HURRICANE CENTER FORECASTS THE
SYSTEM MAY REACH MINIMAL HURRICANE STRENGTH WHILE TRACKING UP OFF
THE ERN SEABOARD...HELD OFFSHORE BY AN ERN US MID-UPPER LEVEL
TROUGH THAT PERSISTS DURING BERTHA PASSAGE. A TRAILING WAVY FRONT
SHOULD ALLOW MOISTURE/CONVECTION TO LINGER OVER THE COASTAL ERN US
AND THE SERN US...WITH SLOW MOVING VORT ENERGIES BACK NEAR THE
CENTRAL GULF COAST ALSO PROVIDING SOME LOCAL DOWNPOURS.

ELSEWHERE...HIGH LATITUDE BLOCKY FLOW ESTABLISHED FROM THE NERN
PACIFIC INTO CANADA GRADUALLY WEAKENS NEXT WEEK LEADING NOW TO
MORE SIGNIFICANT DETERMINISTIC MODEL VARIANCE AND LESS RUN TO RUN
CONTINUITY WITH REPSECT TO EMBEDDED WEATHER SYSTEMS
TIMING/AMPLITUDE AND SENSIBLE WEATHER FOCUS.

WHILE MORE SUPPRESED THAN YESTERDAY AMID GROWING
UNCERAINTY...CENTRAL US TO MIDWEST/OH VALLEY LOW PRESSURE AND
TRAILING PLAINS/MS VALLEY FRONT APPROACH INTO A LEAD WARM SECTOR
SHOULD FAVOR ORGANIZED CONVECTION MID THROUGH LATE NEXT WEEK AS
FUELED BY RETURNING GULF MOISTURE. THIS PATTERN STILL FAVORS SOME
LEAD THETAE ADVECTION AND MCS/NOCTURAL CONVECTION AND REPEAT CELL
RAINFALL THREAT SINKING FROM THE MIDWEST INTO KY/TN...SPILLING
SEWD INTO THE MID-ATLC AND SRN APPALACHIANS.

MEANWHILE...AMPLE ENERGY ROTATING ON AMPLIFIED RIDGE PERIPHERY
THROUGH THE SWRN US/GREAT BASIN AND ROCKY STATES SHOULD FEED ON
MONSOONAL MOISTURE TO FOCUS AN ACTIVE CONVECTIVE PATTERN NEXT
WEEK...ESPECIALLY WITH FAVORED TERRAIN/UPSLOPE WHERE SOME
MODERATELY HEAVY LOCAL AMOUNTS ARE POSSIBLE.

THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A
BLEND OF CONTINUITY WITH REASONABLY COMPATABLE GUIDANCE FROM THE
12 UTC GEFS/ECMWF ENSEMBLE MEANS...WITH MORE WEIGHTING ON THE
LATTER FOR MAX WPC CONTINUITY.

SCHICHTEL


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