Prognostic Meteorological Discussion
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FXUS02 KWBC 031505
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1104 AM EDT FRI JUL 03 2015

VALID 12Z MON JUL 06 2015 - 12Z FRI JUL 10 2015

...PATTERN OVERVIEW...

MAINTAINED GOOD WPC CONTINUITY WITH DEPICTION OF FLOW ALOFT WITH
RIDGING TENDING TO PREVAIL OVER THE SRN TIER...AN ANOMOLOUS TROUGH
WITH EMBEDDED UPR LOW NEAR THE CA COAST...AND PROGRESSIVE FLOW
WITH MULTIPLE EMBEDDED SHRTWVS ACROSS THE NRN STATES. SIMILARITY
OF MODEL/ENSEMBLE MEAN SOLNS IN DEPICTING THIS GENERAL PATTERN AT
THE MOMENT LEADS TO ABOVE AVG CONFIDENCE IN THE MEAN FLOW. HOWEVER
THE SHRTWV DETAILS WILL LIKELY TAKE A WHILE TO BE RESOLVED GIVEN
THEIR TYPICALLY LOW PREDICTABILITY.

...GUIDANCE EVALUATION/PREFERENCES...

WPC MEDIUM RANGE DAYS 3-7 SURFACE FRONTS/PRESSURE AND 500MB PROGS
HAVE BEEN PRIMARILY DERIVED FROM A COMPOSITE BLEND OF QUITE
COMPATABLE GUIDANCE FROM THE 00 UTC NAEFS/ECMWF ENSEMBLE MEANS.
THE OVERALL FLOW OFFERS SLIGHTLY ABOVE NORMAL PATTERN
PREDICTABILITY...BUT DECIDED TO EXCLUDE DETERMINISTIC MODEL INPUT
INTO THE SOLUTION AFTER CONSIDERATION OF RUN TO RUN SYSTEM
VARIANCE...ESPECIALLY BY MIDWEEK.

AS FOR INDIVIDUAL FEATURES EXPECT ONE FRONT FROM THE UPR MS VLY
SWWD INTO THE PLAINS TO PROGRESS E/NE WITH TIME. BY MIDWEEK THERE
IS INCREASING UNCERTAINTY OVER EWD EXTENT OF THIS FRONT
CORRESPONDING TO HOW AMPLIFIED SUPPORTING SHRTWV ENERGY WILL BE BY
THAT TIME. THE 12Z/2 ECMWF BECAME FAIRLY AMPLIFIED WITH ITS SHRTWV
AND THUS MORE PROGRESSIVE WITH THE FRONT. NEW 00Z SOLNS THUS FAR
DO NOT CLARIFY THINGS AS THE GFS TRENDS TOWARD SOME 12Z ECMWF
IDEAS...BUT THE GEFS MEAN ACTUALLY HAS SOME OF THE WEAKEST HGT
FALLS ALOFT OVER THE NORTHEAST BY TUE-WED...WITH THE UKMET/CMC
DETAILS DIFFERENT AS WELL. THERE IS DECENT AGREEMENT REGARDING
ANOTHER FRONT REACHING THE NRN TIER BY DAY 5 WED WITH A LEADING
WAVE EMERGING FROM THE NRN HIGH PLAINS. THE PRIMARY FEATURE ALONG
THE EAST COAST WILL BE A NWD MOVING WAVE/FRONT WHOSE TIMING MAY BE
INFLUENCED BY SOME DEGREE TO THE FLOW IMMEDIATELY TO THE NW.
GREATER PROGRESSION UPSTREAM AS IN THE 00Z GFS/ECMWF WOULD LEAD TO
FASTER NWD MOVEMENT OF THE EAST COAST FEATURE VERSUS THE CURRENTLY
PREFERRED ECMWF/NAEFS ENSEMBLE MEANS.

...SENSIBLE WEATHER HIGHLIGHTS...

A DECENT PERCENTAGE OF THE CONUS SHOULD SEE ONE OR MORE EPISODES
OF CONVECTION NEXT WEEK. BEST POTENTIAL FOR HIGHEST RNFL TOTALS
SHOULD BE FROM THE S-CNTRL PLAINS INTO THE MID MS VLY AND PSBLY
CONTINUING INTO THE GRTLKS/OH VLY/TN VLY...ALONG AND S OF A
DECELERATING SFC FRONT. PROXIMITY OF THE ERN PAC-CA COAST UPR
TROUGH/CLOSED LOW SHOULD SUPPORT SOME ACTIVITY JUST INLAND FROM
THE CNTRL WEST COAST WITH MULTIPLE IMPULSES EJECTING FROM THIS
TROUGH ALSO ENCOURAGING CONVECTIVE DEVELOPMENT AND SOME COOLING
DOWNSTREAM OVER THE FAR WEST WITH TIME. MEANWHILE THE SOUTHEAST
SHOULD SEE DIURNALLY FAVORED SHWRS/TSTMS AND SOME AREAS FARTHER
NWD NEAR THE EAST COAST MAY SEE SOME ENHANCEMENT IN RNFL FROM THE
NWD MOVING WAVE/FRONT.

SCHICHTEL

$$





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