Prognostic Meteorological Discussion
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000
FXUS10 KWNH 240640
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
239 AM EDT SUN JUL 24 2016

VALID JUL 24/0000 UTC THRU JUL 27/1200 UTC

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

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


...CLOSED UPPER LOW RETROGRADING TOWARD THE FL PENINSULA THROUGH
SUN...
...CROSSING THE GULF OF MEXICO AND REACHING THE TX COAST
TUES/WED...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

AN UPPER LOW JUST EAST OF THE FL PENINSULA WILL RETROGRADE WEST
OVER THE NEXT FEW DAYS...CROSSING THE PENINSULA ON SUN...AND THEN
TRAVERSING THE GULF OF MEXICO BEFORE REACHING THE TX COAST BY TUES
AND WED. THE 00Z NAM IS SOMEWHAT DEEPER THAN THE MODEL CONSENSUS
ONCE AGAIN...WITH THE REMAINING MODELS RATHER WELL CLUSTERED. THUS
WILL AGAIN PREFER A NON-NAM CONSENSUS.


...SHORTWAVE CROSSING THE US/CANADA BORDER SUN/MON...
...TROUGH CROSSING THE NORTHEAST TUES...
...COLD FRONT CROSSING THE NORTHERN TIER STATES...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

A PROGRESSIVE MID LEVEL TROUGH WILL TRACK ALONG THE US/CANADIAN
BORDER ON SUN AND MON BEFORE THEN FOCUSING WELL INTO SOUTHEAST
CANADA ON TUES. THE SOUTHERN EXTENSION OF THE TROUGH WILL CROSS
THE NORTHEAST AND THIS WILL ALLOW A COLD FRONT TO ADVANCE ACROSS
THE GREAT LAKES AND NORTHEAST THROUGH THE PERIOD. THE 00Z NAM
APPEARS TO BE TOO AMPLIFIED WITH THE ENERGY AS IT CROSSES THE
NORTHEAST. THE GLOBAL MODELS WITH SUPPORT FROM THE ENSEMBLE MEANS
FAVOR A LESS-AMPLIFIED SYSTEM BY COMPARISON...AND SO A NON-NAM
CONSENSUS WILL BE PREFERRED HERE.


...LOW-AMPLITUDE SHORTWAVE CROSSING THE MIDWEST TUES/WED...

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

THE GUIDANCE SHOWS A LOW-AMPLITUDE SHORTWAVE EMBEDDED WITHIN THE
DEEPER LAYER WESTERLIES CROSSING THE MIDWEST TUES AND WED. THE 00Z
NAM APPEARS TO BE TOO DEEP WITH THIS SYSTEM...WITH THE 00Z UKMET
POSSIBLY TOO WEAK. THE STRONGER MODEL CLUSTERING RESIDES WITH THE
00Z GFS AND 00Z ECMWF IN BETWEEN...AND SO A BLEND OF THESE
SOLUTIONS WILL BE PREFERRED.


...TROUGH OVER THE NORTHWEST TUES/WED...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE MODELS HAVE A TROUGH LINGERING OVER THE NORTHWEST TUES AND
WED. ONLY MINOR DIFFERENCES WITH TIMING/DEPTH EXIST WITH THIS
SYSTEM...SO A GENERAL MODEL COMPROMISE WILL BE PREFERRED.

ORRISON

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

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

$$





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