Prognostic Meteorological Discussion
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000
FXUS10 KWNH 031658
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1257 PM EDT FRI JUL 03 2015

VALID JUL 03/1200 UTC THRU JUL 07/0000 UTC

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

12Z MODEL EVALUATION...INCLUDING THE NAM/GFS WITH INITIAL
PREFERENCE AND CONFIDENCE


...UPPER TROUGH MOVING THROUGH WESTERN/CENTRAL CANADA THROUGH SAT
AND SUN...
...COLD FRONT CROSSING THE NORTHERN PLAINS/UPPER MS VALLEY...

PREFERENCE: 12Z GFS/00Z ECMWF
CONFIDENCE: ABOVE AVERAGE

THE 12Z NAM IS WITHIN THE SPREAD OF SOLUTIONS ACROSS CENTRAL
CANADA DURING DAY 1 INTO DAY 2...BUT BECOMES SLOWER AND DEEPER
WITH TIME ACROSS THE NORTHERN PLAINS DURING DAY 3. THE
CORRESPONDING SURFACE FRONT IS SLOW AS WELL...ESPECIALLY BY DAY 3
ACROSS THE GREAT LAKES. . THE 12Z GFS REMAINS CLOSE TO THE 00Z
ECMWF WITH BOTH THE MID LEVEL SYSTEM AND THE COLD FRONT.


...SURFACE WAVE MOVING THROUGH THE OH VALLEY AND MID-ATLANTIC
THROUGH SAT...

PREFERENCE: NON-CMC CONSENSUS
CONFIDENCE: ABOVE AVERAGE

THE 12Z NAM SLOWS DURING THE LATER STAGES OF DAY 1 ACROSS THE MID
ATLANTIC WITH THE MID LEVEL SHORT WAVE...AND ITS ASSOCIATED
SURFACE FRONT ALSO SLOWS WITH RESPECT TO THE CONSENSUS. THE 12Z
GFS IS IN THE MIDDLE OF THE CONSENSUS WITH THE MID LEVEL SYSTEM.
THE SURFACE LOW...WHILE A TAD SLOW EARLY...CATCHES UP TO THE
CONSENSUS BY THE END OF DAY 1...AND REMAINS THERE INTO DAY 2. THE
00Z CMC IS THE SLOWEST SOLUTION WITH THE SURFACE LOW...AND WAS NOT
PART OF THE PREFERRED SOLUTION.


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

PREFERENCE: 12Z GFS/00Z ECMWF
CONFIDENCE: AVERAGE

THE 12Z NAM IS SLOWER AND DEEPER THAN THE CONSENSUS WITH THE
TROUGH ACROSS NEW ENGLAND DURING DAY 1. THE 12Z GFS HAS SPED UP
ITS SOLUTION AND IS NOW VERY CLOSE TO THE 00Z ECMWF SOLUTION. THE
00Z CMC IS SLOWER WITH THIS FEATURE...AND THE 00Z UKMET BECOMES
FASTER WITH TIME. IN AN ATTEMPT TO MITIGATE SOME OF THE
DIFFERENCES...A 12Z GFS/00Z ECMWF SOLUTION IS PREFERRED.


...UPPER TROUGH CROSSING THE GULF COAST STATES/SOUTHEAST SUN AND
MON...

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

THE 12Z NAM IS SLOWER AND DEEPER WITH THE CROSSING THE GULF COAST
STATES ON DAY 1...AND REMAINS SLOWER AND DEEPER THAN THE CONSENSUS
THROUGH DAYS 2 AND 3. THE 12Z IS CLOSER TO THE CONSENSUS ON DAY
1...BUT BECOMES SLOWER AND DEEPER WITH TIME (EVENTUALLY BECOMING
SLOWER THAN THE 12Z NAM). THE 00Z UKMET APPEARS OVERALL TO BE TOO
WEAK WITH THE TROUGH. THE STRONGER MODEL CLUSTERING INVOLVES THE
00Z CMC AND THE 00Z ECMWF...AND A BLEND OF THESE SOLUTIONS 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...

HAYES/CHENARD

$$





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