Prognostic Meteorological Discussion
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11
000
FXUS10 KWNH 030403
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1202 AM EDT FRI JUL 03 2015

VALID JUL 03/0000 UTC THRU JUL 06/1200 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 WESTERN/CENTRAL CANADA THROUGH SAT
AND SUN...
...COLD FRONT CROSSING THE NORTHERN PLAINS/UPPER MS VALLEY...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: ABOVE AVERAGE

AN UPPER LOW AND ASSOCIATED TROUGH AXIS WILL BE CROSSING WESTERN
AND CENTRAL CANADA THROUGH THE PERIOD...WITH THE SOUTHERN PORTION
OF THE TROUGH EXPECTED TO CROSS THE NORTHERN PLAINS. THIS WILL
DRIVE A COLD FRONT EAST ACROSS THE NORTHERN PLAINS AND INTO THE
UPPER MS VALLEY BY THE END OF THE PERIOD. THE 00Z NAM BECOMES A
SLOW OUTLIER WITH THE FRONT AFTER ABOUT 48 HOURS...AND WITH THE
OVERALL TROUGH AXIS ALOFT BY 60 HOURS. THE REMAINING MODELS ARE
WELL CLUSTERED WITH TIMING AND DEPTH...AND SO A NON-NAM CONSENSUS
WILL BE PREFERRED.


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

PREFERENCE: NON-CMC CONSENSUS
CONFIDENCE: ABOVE AVERAGE

A MID LEVEL SHORTWAVE TROUGH CURRENTLY OVER THE MID MS VALLEY WILL
ADVANCE EAST ACROSS THE OH VALLEY AND MID-ATLANTIC REGION FRI AND
SAT ALONG WITH A WAVE OF LOW PRESSURE THAT WILL BE TRAVERSING A
FRONTAL ZONE. THE WAVE SHOULD EXIT OFFSHORE THE EAST COAST BY LATE
SAT. THE 12Z CMC IS THE SLOWEST SOLUTION OF THE CURRENT MODEL
SUITE...WITH THE REMAINING MODELS REASONABLY WELL CLUSTERED WITH
TIMING AND DEPTH. A NON-CMC CONSENSUS WILL BE PREFERRED AT THIS
TIME.


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

PREFERENCE: BLEND OF THE 12Z ECMWF AND 12Z UKMET
CONFIDENCE: AVERAGE

THE MODELS REMAIN IN FAIRLY GOOD AGREEMENT WITH THE SHORTWAVE AND
ASSOCIATED LOW THAT TRAVERSES NORTHERN PORTIONS OF THE GREAT LAKES
AND NEW ENGLAND THIS WEEKEND. HOWEVER...THE 00Z NAM AND TO AN
EXTENT THE 12Z CMC BECOME TOO SLOW WITH THE TROUGH EVOLUTION. THE
00Z GFS FOR ITS PART APPEARS TO BE A JUST A TAD TOO DEEP OVER
NORTHERN NEW ENGLAND...AND AS A RESULT TRIES TO BRING THE EXITING
MID-ATLANTIC SURFACE LOW IN A LITTLE CLOSER TO THE NEW ENGLAND
COAST COMPARED TO THE OTHER MODELS. THIS LEAVES THE 12Z ECMWF AND
12Z UKMET SOLUTIONS WHICH APPEAR REASONABLE AT THE SURFACE AND
ALOFT...AND A BLEND OF THESE SOLUTIONS WILL BE PREFERRED.


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

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

SHORTWAVE ENERGY DIGGING THROUGH THE BASE 0F THE EASTERN U.S.
TROUGH WILL BEGIN TO DETACH ITSELF AND ATTEMPT TO CUT OFF OVER THE
GULF COAST STATES AND SOUTHEAST SUN INTO MON. THE 12Z UKMET
APPEARS OVERALL TO BE TOO WEAK WITH THE TROUGH. THE 00Z NAM
APPEARS TO BE HANGING ON TO TOO MUCH ENERGY FARTHER WEST OVER THE
LOWER MS VALLEY BY MON...AND ALSO HAS A NOTABLY STRONGER RIDGE
BUILDING NORTH OF THE TROUGH OVER THE OH VALLEY AND NORTHERN
MID-ATLANTIC REGION. THE STRONGER MODEL CLUSTERING INVOLVES THE
00Z GFS AND THE 12Z 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...

ORRISON
$$





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