Prognostic Meteorological Discussion
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000
FXUS02 KWBC 291600
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1159 AM EDT FRI MAY 29 2015

VALID 12Z MON JUN 01 2015 - 12Z FRI JUN 05 2015

...PATTERN/GUIDANCE EVALUATION AND SENSIBLE WEATHER
HIGHLIGHTS/THREATS...

THE WPC MEDIUM-RANGE PRODUCT SUITE IS PRIMARILY DERIVED FROM A
BLEND OF THE 06 UTC GEFS/00 UTC ECMWF ENSEMBLE MEANS. THE 06 UTC
GFS IS ALSO GENERALLY IN LINE.

WE THANKFULLY EXPECT MOST OF THE SRN PLAINS TO SEE A PROLONGED
PERIOD OF MUCH DRIER WEATHER THAN IN RECENT WEEKS. A PERSISTENT
FAVORED AREA FOR HIGHER RNFL TOTALS WITH SOME THREAT FOR LOCALLY
EXCESSIVE DOWNPOURS WILL REMAIN OVER THE SERN THIRD OF THE CONUS
WITH A SLOWLY WEAKENING MID-ATLANTIC TO LOWER MS VALLEY SURFACE
FRONT. THE WPC SCENARIO ALLOWS FOR SOME TREND OF SWINGING A MORE
AMPLIFIED NRN STREAM MID-UPPER LEVEL TROUGH OVER THE GREAT
LAKES/NERN US NEXT WEEK GIVEN UPSTREAM AMPLIFICATION. HOWEVER...AT
THIS POINT ITS NOT AS AMPLIFIED AS THE 00 UTC ECMWF THAT MAY HAVE
SOME PHASING ISSUES AND WHOSE LEAD SURFACE LOW
DEVELOPMENT...EVENTUALLY TO NERN US COASTAL AREAS SEEMS QUITE THE
RUN-RUN CHANGE.

IN THIS PATTERN A MEANDERING UPPER LOW CUT OVER THE LOWER MS
VALLEY/CENTRL GULF COAST WOULD AID ACTIVITY. THE WPC OFFERS A LESS
PROGRESSIVE UPPER LOW THAN THE 00 UTC ECMWF CONSIDERING UPSTREAM
RIDGING...WPC CONTINUITY...AND OVERALL SLOW NATURE OF THE OVERALL
PATTERN. IN THIS SCENARIO...SRN/ERN PARTS OF THE FL PENINSULA
EXPERIENCE PERIODS OF ENHANCED RNFL NEAR AN INVERTED SFC TROUGH
OFFERED BY SOME GUIDANCE...BUT WITH LESS LATE PERIOD PROXIMITY OF
THE UPPER LOW.

AN ANOMALOUSLY WIDESPREAD AREA OF ORGANIZED RNFL/CONVECTION SHOULD
BE FROM THE NWRN US TO N-CENTRAL INTERMOUNTAIN WEST/ROCKIES WITH
WRN US HEIGHT FALLS/MID-UPPER LEVEL TROUGH
DEVELOPMENT/REINFORCEMENT. THE WPC SCENARIO FOLLOWS RECENT
GUIDANCE TRENDS TOWARD MORE AMPLIFIED MID-UPPER LEVEL TROUGH
INFUSION INTO THE WRN US GIVEN UPSTREAM FLOW INFLUENCE.
ACCORDINGLY...ENERGY EJECTING DOWNSTREAM INTO THE N-CENTRAL US IN
ASSOCIATION WITH MULTIPLE/UNCERTAIN FRONTAL WAVES AND ENHANCED
INFLOW/LIFT SHOULD ALSO LEAD TO A FAVORED AREA OF CONVECTION WITH
SOME LOCALLY HEAVY RAINFALL WITH SOME SEVERE POTENTIAL THAT IS
BEING MONITORED BY SPC.

MEANWHILE...THE NHC IS ALSO MONITORING EARLY SEASON TROPICAL STORM
ANDRES WELL OFFSHORE OVER THE TROPICAL ERN PACIFIC. ANDRES IS
CURRENTLY PACKING SUSTAINED WINDS OF 60 KTS AND IS EXPECTED TO
FURTHER STRENGTHEN TO A HURRICANE LATER TODAY.

SCHICHTEL

$$




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