Prognostic Meteorological Discussion
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FXUS10 KWNH 050633
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
233 AM EDT SUN JUL 05 2015

VALID JUL 05/0000 UTC THRU JUL 08/1200 UTC

...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...

00Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/CMC AND ECMWF

...UPPER TROUGH MOVING THROUGH WESTERN/CENTRAL CANADA SUN AND
MON...
...COLD FRONT CROSSING THE NORTHERN PLAINS TO THE MIDWEST/GREAT
LAKES/NORTHEAST...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: AVERAGE

A LONGWAVE TROUGH CROSSES WESTERN AND CENTRAL CANADA THROUGH
MON...WITH THE SOUTHERN PORTION OF THE LONGWAVE BRUSHING THE
NORTHERN PLAINS/UPPER MIDWEST AND GREAT LAKES REGION. THIS ENERGY
WILL DRIVE A COLD FRONT ACROSS THE NORTHERN AND CENTRAL PLAINS AND
THEN THROUGH THE GREAT LAKES AND NORTHEAST BY THE END OF THE
PERIOD. THE 00Z NAM GRADUALLY LAGS THE MULTI-MODEL CONSENSUS WITH
THE TROUGH AXIS...AND ALSO WITH THE DETAILS OF THE FRONTAL
PROGRESSION...ESPECIALLY AS THE ENERGY CROSSES THE GREAT LAKES AND
NORTHEAST LATER IN THE SHORT RANGE PERIOD. SOME RELATIVELY MODEST
TIMING DIFFERENCES ARE NOTED WITH THE WAVE LIFTING NORTHEAST ALONG
THE BOUNDARY ACROSS THE MIDWEST AND GREAT LAKES...BUT AT THIS
POINT A NON-NAM CONSENSUS WILL BE RECOMMENDED TO RESOLVE THESE
DIFFERENCES.


...SHORTWAVE CLIPPING THE GREAT LAKES/NORTHERN NEW ENGLAND THROUGH
SUN...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE MODELS SHOW GOOD AGREEMENT IN HANDLING THIS PROGRESSIVE
SHORTWAVE CROSSING NEW ENGLAND ON SUN. A GENERAL MODEL COMPROMISE
WILL BE PREFERRED.


...UPPER TROUGH CROSSING THE TN VALLEY/MID-ATLANTIC THROUGH MON
AND TUES...

PREFERENCE: BLEND OF THE 00Z GFS AND 00Z ECMWF
CONFIDENCE: AVERAGE

SHORTWAVE ENERGY DROPPING INTO THE BASE OF THE EASTERN UNITED
STATES TROUGH WILL SLOWLY BECOME DETACHED FROM THE TROUGH ON SUN
OVER THE TN VALLEY AND BECOME A CLOSED MID LEVEL SYSTEM. THE
ENERGY IS THEN EXPECTED TO LIFT NORTHEAST ACROSS THE MID-ATLANTIC
MON AND TUES WHILE GRADUALLY SHEARING OUT. THE 00Z NAM IS A TAD
SLOWER AND DEEPER THAN THE MULTI-MODEL CONSENSUS WITH THIS ENERGY.
THE 00Z UKMET BECOMES SLIGHTLY FASTER AND WEAKER THAN THE
CONSENSUS...WITH THE 00Z GFS/00Z ECMWF AND 00Z CMC REFLECTING
STRONGER CLUSTERING/AGREEMENT. WILL MAINTAIN CONTINUITY AND PREFER
A BLEND OF THE GFS AND ECMWF.


...SHORTWAVE CROSSING THE SOUTHWEST AND SOUTHERN PLAINS MON AND
TUES...

PREFERENCE: BLEND OF THE 00Z GFS AND 00Z ECMWF
CONFIDENCE: AVERAGE

A SHORTWAVE EJECTED FROM A CLOSED MID LEVEL SYSTEM OFF THE
CALIFORNIA COAST WILL TRAVERSE THE MID LEVEL FLOW ACROSS THE
SOUTHWEST AND SOUTHERN ROCKIES BEFORE AMPLIFYING OVER THE SOUTHERN
PLAINS BY TUES. THE 00Z NAM IS THE STRONGEST SOLUTION WITH THIS
ENERGY BY TUES AS IT REACHES THE SOUTHERN HIGH PLAINS. THE 00Z CMC
IS THE WEAKEST...WITH THE 00Z GFS/00Z ECMWF AND 00Z UKMET ALL
CLUSTERED A BIT STRONGER BUT NOT QUITE TO THE EXTENT OF THE 00Z
NAM. A BLEND OF THE 00Z GFS AND 00Z ECMWF WILL CONTINUE TO BE
PREFERRED.


...EASTERN PACIFIC UPPER LOW APPROACHING CALIFORNIA BY TUES...

PREFERENCE: NON-UKMET CONSENSUS
CONFERENCE: ABOVE AVERAGE

ALL MODELS TAKE AN UPPER LOW OVER THE EASTERN PACIFIC CURRENTLY
CENTERED NEAR 33N 130W SLOWLY EASTWARD INTO EARLY NEXT WEEK. THE
00Z UKMET IS A TAD SOUTH OF THE MULTI-MODEL CONSENSUS BY THE END
OF THE PERIOD. GIVEN THAT THE REMAINING MODELS ARE SO WELL
CLUSTERED...A NON-UKMET CONSENSUS WILL BE PREFERRED.


...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...

...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

ORRISON
$$





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