Prognostic Meteorological Discussion
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945
FXUS10 KWNH 290431
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1230 AM EDT MON AUG 29 2016

VALID AUG 29/0000 UTC THRU SEP 01/1200 UTC

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

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


...UPPER TROUGH CROSSING NEW ENGLAND ON MON...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE MODELS ARE IN VERY GOOD AGREEMENT WITH THIS SYSTEM.


...UPPER TROUGH TRACKING ACROSS SOUTHERN CANADA THROUGH MID-WEEK...
...TROUGH AMPLIFICATION INTO THE EASTERN U.S....
...ATTENDANT COLD FRONT PROGRESSION...

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

THE 12Z UKMET IS A TAD MORE AGGRESSIVE WITH THE EVOLUTION OF
HEIGHT FALLS CROSSING SOUTHERN CANADA AND THEN AMPLIFYING
SOUTHEAST ACROSS THE GREAT LAKES AND INTO THE EASTERN U.S. THIS
PERIOD. THE CONSENSUS OF THE REMAINING GUIDANCE THOUGH DOES
SUPPORT A ROBUST TROUGH DIGGING TOWARD THE SOUTHEAST OVER THE NEXT
FEW DAYS AND THIS WILL SEND A COLD FRONT ACROSS THE GREAT LAKES/OH
VALLEY AND INTO THE EASTERN U.S. BY MIDWEEK. BETTER MODEL
CLUSTERING LIES WITH THE 00Z GFS AND 12Z ECMWF AND A BLEND OF
THESE SOLUTIONS WILL BE PREFERRED.


...UPPER LOW/TROUGH DIGGING SOUTH OFFSHORE BRITISH COLUMBIA...
...ENERGY PIVOTING INTO THE WEST COAST BY LATE TUES/WED...
...LEAD SHORTWAVE CROSSING NORTHERN CA ON TUES...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

MINOR TIMING/STRENGTH DIFFERENCES EXIST WITH THE LATEST SUITE OF
MODELS REGARDING BOTH THE LARGE UPPER LOW/TROUGH SINKING SOUTH OFF
OF THE BRITISH COLUMBIA COASTLINE THROUGH MIDWEEK...AND WITH A
COMPACT VORTICITY MAX/SHORTWAVE ADVANCING INTO THE COAST OF
NORTHERN CA BY EARLY TUES. WILL RECOMMEND A GENERAL MODEL
COMPROMISE WITH THE EVOLUTION OF ALL OF THIS ENERGY GIVEN THE
LARGER SCALE MASS FIELD AGREEMENT.


...MID-UPPER LEVEL TROUGH OVER THE SOUTHWEST...
...ENERGY WEAKENING TOWARD THE HIGH PLAINS THROUGH WED...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE MODELS ARE IN RELATIVELY GOOD AGREEMENT ON THE EVOLUTION OF
THIS GRADUALLY WEAKENING SYSTEM. THE 00Z NAM DOES TEND TO STILL
HANG INTO A SOMEWHAT STRONGER SYSTEM...WITH THE GLOBAL MODELS A
LITTLE WEAKER. WILL PREFER A NON-NAM CONSENSUS.


...WEAK MID LEVEL LOW OVER THE WESTERN GULF COAST...

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

THIS SYSTEM IS EXPECTED TO GRADUALLY WEAKEN OVER THE NEXT COUPLE
OF DAYS AS IT LINGERS NEAR THE WESTERN GULF COAST AND SOUTHEAST TX
COASTAL PLAIN. MINOR DIFFERENCES ARE SEEN WITH THE LARGER SCALE
MASS FIELDS...BUT THE VORTICITY FIELDS ARE BETTER CLUSTERED
BETWEEN THE 00Z GFS AND 12Z ECMWF...AND SO A BLEND OF THESE
SOLUTIONS WILL BE PREFERRED.


...T.D. EIGHT MOVING TOWARD THE MID-ATLANTIC COAST...

PREFERENCE: PLEASE CONSULT THE LATEST NHC FORECAST ADVISORY

THE 00Z NAM/12Z UKMET AND 12Z CMC ARE ALL A TAD WEST OF THE 03Z
NHC TRACK BY LATE TUES AND WED WITH T.D. EIGHT. THE 12Z GFS AND
00Z ECMWF DO NOT TAKE THE SYSTEM QUITE AS FAR WEST BY
COMPARISON...AND SHOW THE BEST AGREEMENT TO THE 03Z NHC ADVISORY
TRACK...WHICH INDICATES THE LOW CENTER APPROACHING THE N.C. OUTER
BANKS BY LATE TUES AND THEN RECURVING AWAY FROM THE EAST COAST WED
AND THURS IN RESPONSE TO A STRONG UPPER TROUGH APPROACHING FROM
THE GREAT LAKES. PLEASE CONSULT THE LATEST NHC FORECAST ADVISORY
FOR MORE INFORMATION ON T.D. EIGHT.


...T.D. NINE MOVING INTO THE GULF OF MEXICO...

PREFERENCE: PLEASE CONSULT THE LATEST NHC FORECAST ADVISORY

THE 00Z NAM IS SLOWER AND WELL TO THE RIGHT OF THE NHC FORECAST
TRACK OF T.D. NINE THIS PERIOD...WHILE THE 12Z CMC IS MUCH
STRONGER THAN ANY OTHER MODEL AND IS ALSO FARTHEST TO THE LEFT.
THE NHC TRACK IS CLOSEST TO A CONSENSUS OF THE 00Z GFS AND 12Z
ECMWF...ALBEIT A TAD FASTER...WHICH SUGGESTS A TRACK OF T.D. NINE
INTO THE CENTRAL GULF OF MEXICO BY TUES BEFORE THEN RECURVING TO
THE NORTHEAST GULF OF MEXICO BY THURS AND QUICKLY APPROACHING
NORTHERN FL. PLEASE CONSULT THE LATEST NHC FORECAST ADVISORY FOR
MORE INFORMATION ON T.D. NINE.

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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