Prognostic Meteorological Discussion
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FXUS10 KWNH 060434
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1233 AM EDT MON JUL 06 2015

VALID JUL 06/0000 UTC THRU JUL 09/1200 UTC

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

00Z MODEL EVALUATION...INCLUDING THE NAM AND GFS

...UPPER TROUGH MOVING THROUGH CENTRAL/EASTERN CANADA MON/TUES...
...COLD FRONT CROSSING THE CENTRAL PLAINS/GREAT LAKES/NORTHEAST...

PREFERENCE: BLEND OF THE 00Z GFS AND 12Z ECMWF
CONFIDENCE: AVERAGE

MASS FIELD DIFFERENCES ALOFT WITH THE TROUGH PROGRESSION ARE
RATHER MINIMAL...BUT THERE IS A BIT MORE SPREAD AT THE SURFACE
WITH THE FRONT. THE 12Z UKMET/12Z CMC SOLUTIONS ARE QUICKER TO
BRING THE FRONT THROUGH THE NORTHEAST TUES NIGHT...WITH THE 00Z
NAM BECOMING THE SLOWEST. THE 00Z GFS AND 12Z ECMWF ARE MORE
STRONGLY CLUSTERED...AND A BLEND OF THESE TWO SOLUTIONS WILL BE
PREFERRED.


...UPPER TROUGH CROSSING THE UPPER OHIO VALLEY AND CENTRAL
APPALACHIANS...

PREFERENCE: NON-UKMET CONSENSUS
CONFIDENCE: ABOVE AVERAGE

MOST OF THE MODELS SHOW REASONABLE AGREEMENT HERE...BUT THE 12Z
UKMET REMAINS WEAKER AND SLIGHTLY FASTER THAN THE AGREEABLE AND
NOW TIGHTLY CLUSTERED DETERMINISTIC/ENSEMBLE CONSENSUS.


...SHORTWAVE CROSSING THE SOUTHWEST AND CENTRAL/SOUTHERN PLAINS...
...DEVELOPING SURFACE LOW LIFTING TOWARD THE MIDWEST...

PREFERENCE: 12Z ECMWF
CONFIDENCE: AVERAGE

A MID LEVEL SHORTWAVE EMBEDDED WITHIN THE SOUTHWEST FLOW AHEAD OF
THE APPROACHING WEST COAST UPPER LOW IS FORECAST TO ADVANCE EAST
OUT INTO THE CENTRAL AND SOUTHERN HIGH PLAINS TUES AND WED AND
AMPLIFY SOMEWHAT. THIS WILL ALSO DEVELOP AND AREA OF LOW PRESSURE
NORTH OF THE RED RIVER VALLEY THAT WILL ADVANCE NORTHEAST TOWARD
THE MIDWEST BY WED. THE 12Z UKMET AND 00Z GFS ARE THE
WEAKEST/FASTEST SOLUTIONS WITH THE HEIGHT FALLS...WITH THE 00Z NAM
THE STRONGEST...AND THIS THEME TENDS TO APPLY TO THE DETAILS OF
THE SURFACE WAVE AS WELL. BY THE END OF THE PERIOD..THE 12Z CMC
BECOMES THE SLOWEST SOLUTION AT THE SURFACE WITH THE 12Z UKMET AND
00Z GFS THE FASTEST. THE 12Z ECMWF AND 00Z NAM AND THAT POINT
SPLIT THE DIFFERENCE. THE 12Z ECMWF OFFERS A NICE COMPROMISE
SOLUTION IN BETWEEN THE SLOWER AND FASTER CAMPS AT THE SURFACE AND
ALOFT AND THIS WILL BE THE PREFERENCE.


...EASTERN PACIFIC UPPER LOW HOVERING WEST OF CALIFORNIA THROUGH
WED...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFERENCE: ABOVE AVERAGE

ALL OF THE LATEST DETERMINISTIC GUIDANCE TAKES AN UPPER LOW OVER
THE EASTERN PACIFIC CURRENTLY CENTERED NEAR 35N 130W SLOWLY
EASTWARD INTO THE MIDDLE OF THE WEEK WITH REASONABLE AGREEMENT.
THUS A GENERAL MODEL COMPROMISE 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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