Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4
000
FXUS10 KWNH 280657
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
256 AM EDT SUN AUG 28 2016

VALID AUG 28/0000 UTC THRU AUG 31/1200 UTC

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

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


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

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: ABOVE AVERAGE

THE 00Z NAM BECOMES A SLOWER AND DEEPER OUTLIER RELATIVE TO THE
WELL CLUSTERED GLOBAL MODELS WITH THIS SYSTEM. WILL PREFER A
NON-NAM CONSENSUS.


...UPPER TROUGH CROSSING SOUTHERN CANADA SUN/MON...
...COLD FRONT CROSSING THE NORTHERN PLAINS/UPPER MIDWEST...

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

THERE IS SOMEWHAT BETTER MODEL CLUSTERING WITH THIS SYSTEM...BUT
THE 00Z CMC STILL TENDS TO BE PERHAPS A TAD TOO PROGRESSIVE WITH
ITS HEIGHT FALLS. THE 00Z NAM AT THIS POINT TENDS TO ALSO LOOK A
BIT TOO DEEP BY THE END OF THE PERIOD WITH ITS HEIGHT FALLS
DROPPING INTO THE GREAT LAKES REGION AND IS ALSO SLOW WITH ITS
COLD FRONT. THE 00Z UKMET IS ALSO NOW SLOWER...BUT MAINLY WITH ITS
UPPER TROUGH. WILL AGAIN PREFER A SOLUTION CLOSER TO THE 00Z GFS
AND 00Z ECMWF GIVEN BETTER MODEL CONTINUITY AND CLUSTERING.


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

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

THE MODELS SHOW REASONABLE AGREEMENT WITH THE LARGER SCALE SYSTEM
THROUGH MOST OF TUES AS RATHER STRONG HEIGHT FALLS DIG SOUTH
OFFSHORE BRITISH COLUMBIA. THIS ENERGY WILL HELP TO KICK THE
REMNANTS OF A COMPACT MID LEVEL LOW CENTER CURRENTLY NEAR 34N 142W
WELL OFF TO THE EAST...AND THE GUIDANCE AGREES IN BRINGING A
REMNANT SHORTWAVE IN ACROSS NORTHERN CA ON TUES AHEAD OF THE
LARGER SCALE TROUGH THAT WILL THEN PIVOT INTO THE WEST COAST BY
LATE TUES AND WED. THE 00Z GFS IS A TAD SLOW ON TUES WITH THE
ENERGY ARRIVING ACROSS NORTHERN CA...BUT THE DIFFERENCE AT THIS
POINT COMPARED TO THE NON-NCEP MODELS IS RATHER MINOR. THE LARGE
SCALE DIFFERENCES ARE ALSO RATHER MINOR WITH THE ARRIVAL OF THE
LONGWAVE TROUGH ALONG THE WEST COAST BY WED. WILL FAVOR A GENERAL
MODEL COMPROMISE.


...MID LEVEL TROUGH OVER THE SOUTHWEST THIS WEEKEND...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

WHILE THERE IS BROAD AGREEMENT WITH THE EVOLUTION OF THIS
FEATURE...THE 00Z NAM ENDS UP ON THE STRONGER SIDE OF THE LATEST
GUIDANCE. WILL PREFER A NON-NAM CONSENSUS WITH THIS.


...LOW PRESSURE APPROACHING THE FL KEYS/STRAITS...
...MOVING INTO THE GULF OF MEXICO MON/TUES...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: AVERAGE

THE DETERMINISTIC GUIDANCE IS GRADUALLY COMING INTO BETTER
AGREEMENT IT SEEMS WITH THE HANDLING OF 99L WHICH WILL BE MOVING
THROUGH THE FL STRAITS TODAY AND GRADUALLY INTO THE SOUTHEAST GULF
OF MEXICO. THE 00Z CMC TRENDED WEAKER AND HAS NOW SHIFTED ITS LOW
TRACK FARTHER WEST AND CLOSER TO THE CLUSTERING OF THE 00Z GFS/00Z
UKMET AND 00Z ECMWF WHICH ARE TAKING A GRADUALLY DEEPENING LOW
CENTER TOWARD THE CENTRAL GULF OF MEXICO BY WED. THE 00Z ECMWF WAS
NOTED THIS CYCLE TO HAVE TRENDED NOTABLY STRONGER VERSUS ITS
PREVIOUS RUN. THE 00Z NAM IS A PATHETIC OUTLIER AT THIS POINT IN
SHOWING A LOW EVOLUTION WELL EAST OF THE GLOBAL MODELS...AND WITH
A SYSTEM THAT RECURVES BY WED INTO THE CENTRAL FL PENINSULA. WILL
PREFER A NON-NAM CONSENSUS GIVEN THE LEVEL OF CLUSTERING AT LEAST
FOR THIS PERIOD SEEN OUT OF THE GLOBAL MODELS.


...WEAK MID LEVEL LOW CENTER OVER THE WESTERN GULF COAST/SOUTHEAST
TX SUN/MON...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

DESPITE SOME MINOR SYNOPTIC DIFFERENCES...THE MODELS SHOW DECENT
AGREEMENT WITH THE TRACK AND INTENSITY OF THIS SYSTEM. GRADUALLY
THIS SYSTEM IS EXPECTED TO DAMPEN OUT BY TUES OVER SOUTH TX.


...MID LEVEL LOW APPROACHING THE SOUTHEAST...
...SURFACE LOW APPROACHING THE NC OUTER BANKS MON/TUES...

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

THE 00Z NAM AND 00Z CMC ARE A LITTLE SLOWER THAN THE 00Z GFS/00Z
UKMET AND 00Z ECMWF WITH THIS SYSTEM AS IT MOVES WEST AND THEN
WEST-NORTHWEST TOWARD THE NC OUTER BANKS BY LATER MON AND TUES.
HOWEVER...BY EARLY WED...THE GUIDANCE BEGINS TO RECURVE THE
SURFACE LOW FEATURE BACK OUT TO SEA. THE UKMET IS A STRONG OUTLIER
LATE IN THE PERIOD...WITH THE CMC ALSO TENDING TO BE RATHER STRONG
WITH THE SYSTEM BY MIDWEEK. GIVEN THE LACK OF A WELL-ORGANIZED
SYSTEM AT THIS POINT...WILL LEAN TOWARD THE WEAKER CONSENSUS AND
SUGGEST A BLEND OF THE GFS AND ECMWF.

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.