Prognostic Meteorological Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10
763
FXUS10 KWNH 240408
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1207 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 AND GFS


...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 NORTHERN NEW ENGLAND TUES...
...COLD FRONT CROSSING THE NORTHERN TIER STATES...

PREFERENCE: NON-NAM BLEND
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 12Z 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 12Z UKMET
POSSIBLY TOO WEAK AND TOO PROGRESSIVE. THE STRONGER MODEL
CLUSTERING RESIDES WITH THE 00Z GFS AND 12Z ECMWF IN BETWEEN...AND
SO A BLEND OF THESE SOLUTIONS WILL BE PREFERRED.


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

PREFERENCE: NON-CMC CONSENSUS
CONFIDENCE: AVERAGE

THE MODELS HAVE A TROUGH LINGERING OVER THE NORTHWEST TUES AND
WED. THE 12Z CMC LOOKS TO BE A BIT TOO DEEP WITH THIS SYSTEM. THE
REMAINING MODELS AGREE WITH A BIT LESS AMPLITUDE...AND SO A
NON-CMC CONSENSUS 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...

$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.