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Model Diagnostics Discussion
 
(Latest Discussion - Issued 0701Z Aug 30, 2016)
 
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Abbreviations and acronyms used in this product
 
Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 AM EDT TUE AUG 30 2016

VALID AUG 30/0000 UTC THRU SEP 02/1200 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 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 00Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE 00Z NAM IS A TAD SLOWER AND DEEPER THAN THE MULTI-MODEL
CONSENSUS WITH THE LARGE SCALE TROUGH AMPLIFYING SOUTHEAST FROM
SOUTHERN CANADA AND INTO THE EASTERN U.S. OVER THE NEXT FEW DAYS.
THE GLOBAL MODELS ARE REASONABLY WELL CLUSTERED THEIR MASS FIELD
EVOLUTION...AND FOR NOW WILL MAINTAIN CONTINUITY AND CONTINUE TO
LEAD TOWARD A GFS/ECMWF BLEND.


...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: BLEND OF THE 00Z GFS/00Z UKMET AND 00Z ECMWF
CONFIDENCE: AVERAGE

THE GUIDANCE IS IN GOOD AGREEMENT ON THE DEPTH AND TIMING OF A
LEAD SHORTWAVE IMPULSE THAT ARRIVES ACROSS NORTHERN CA ON TUES OUT
AHEAD OF A LARGER SCALE DEEP TROUGH AND CLOSED LOW THAT ADVANCES
SOUTH FROM OFFSHORE BRITISH COLUMBIA AND THEN BEGINS DIGGING INTO
THE NORTHWEST U.S. THURS AND FRI. THE 00Z NAM AND 00Z CMC BOTH
GRADUALLY BECOME THE SLOWEST SOLUTIONS TO ADVANCE THE HEIGHT FALLS
INTO PACIFIC NORTHWEST. THE 00Z GFS/00Z UKMET AND 00Z ECMWF
CLUSTER TOGETHER REASONABLY WITH TAD MORE PROGRESSION.
HOWEVER...THE 00Z GFS IS ACTUALLY THE STRONGEST WITH ITS HEIGHT
FALLS. SINCE THE LATEST GEFS MEAN TENDS TO SUPPORT THE SLIGHTLY
STRONGER DETERMINISTIC GFS...WILL SUGGEST A MULTI-MODEL CONSENSUS
HERE...WITH A BLEND OF THE 00Z GFS/00Z UKMET AND 00Z ECMWF.


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

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE MODELS ARE IN REASONABLY GOOD AGREEMENT ON THE EVOLUTION OF
THIS GRADUALLY WEAKENING SYSTEM.


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

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THIS SYSTEM IS EXPECTED TO GRADUALLY WEAKEN AS IT DRIFTS
SOUTHWEST...WITH THE GUIDANCE SHOWING RELATIVELY MINOR DIFFERENCES.


...WAVE DEVELOPING ALONG THE SOUTHEAST COAST WED-THU...

PREFERENCE: 00Z GFS
CONFIDENCE: BELOW AVERAGE

WHILE MOST MODELS ARE INDICATING SOME LOW LEVEL/SURFACE WAVE
DEVELOPMENT OVER NORTHERN FL AND THEN NORTHEAST ALONG A COASTAL
TROUGH POSITIONED ALONG THE GA/SC COAST...THERE IS LARGE SPREAD
WITH RESPECT TO THE TIMING AND AMPLITUDE OF THIS FEATURE. ALL OF
THE GUIDANCE SHOWS THIS LOW CENTER LIFTING NORTHEAST ON THE HEELS
OF T.D. NINE WHICH WILL EXITING AWAY FROM THE EAST COAST. THE 00Z
CMC IS A STRONG OUTLIER SOLUTION. THE 00Z NAM/00Z GFS AND 00Z
UKMET ARE ALL WEAKER...BUT WITH THE 00Z GFS BEING NOTABLY MORE
PROGRESSIVE. THE 00Z ECMWF IS THE WEAKEST SOLUTION OF ALL AND IS A
LITTLE SLOW THAN THE GFS. THE DYNAMICAL SUPPORT FOR THIS LOW WILL
BE A MID/UPPER LEVEL LOW WHICH IS CURRENTLY OFF THE SOUTHEAST
COAST AND EXPECTED TO DRIFT INLAND OVER THE COASTAL PLAIN BEFORE
THEN LIFTING NORTHEAST AHEAD OF THE STRONGER UPPER TROUGH DIGGING
INTO THE EASTERN U.S. THROUGH THE END OF THE WEEK. WILL LEAN
TOWARD THE WEAKER CONSENSUS AT THIS POINT...BUT THE CURRENT
THINKING IS THAT THE ECMWF IS TOO WEAK...AND THUS WILL LEAN TOWARD
THE 00Z GFS AS A COMPROMISE. CONFIDENCE IS LIMITED GIVEN THE MODEL
SPREAD.


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

PREFERENCE: PLEASE CONSULT THE LATEST NHC FORECAST ADVISORY

THE 00Z NAM AND 00Z CMC TAKE T.D. EIGHT A BIT FARTHER WEST THAN
THE MULTI-MODEL CONSENSUS AND THE LATEST NHC TRACK. THE 00Z GFS
AND 00Z ECMWF ARE CLOSEST TO THE NHC TRACK THROUGH WED. THE 00Z
UKMET IS AGAIN A DEEPER OUTLIER. ALL OF THE MODELS INDICATE
RECURVATURE OF T.D. EIGHT BEGINNING ON WED. PLEASE CONSULT THE
LATEST NHC FORECAST ADVISORY FOR MORE INFORMATION.


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

PREFERENCE: PLEASE CONSULT THE LATEST NHC FORECAST ADVISORY

A CONSENSUS OF THE 00Z NAM AND 00Z ECMWF ARE THE CLOSEST TO THE
LATEST NHC TRACK WITH T.D. NINE THIS PERIOD. THE 00Z GFS IS A
LITTLE SLOWER AND ALSO WEAKER WITH THIS SYSTEM BY COMPARISON. THE
00Z UKMET AND 00Z CMC ARE THE SLOWEST SOLUTIONS RELATIVE TO THE
NHC TRACK. PLEASE CONSULT THE LATEST NHC FORECAST ADVISORY FOR
MORE INFORMATION ON T.D. NINE.

ORRISON

www.wpc.ncep.noaa.gov/html/model2.shtml...

www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...