Prognostic Meteorological Discussion
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911
FXUS10 KWNH 260643
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
243 AM EDT FRI AUG 26 2016

VALID AUG 26/0000 UTC THRU AUG 29/1200 UTC

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

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


...MID LEVEL TROUGH CLIPPING THE NORTHERN PLAINS/UPPER MS VALLEY...
...ENERGY LIFTING ACROSS ONTARIO/QUEBEC THROUGH FRI...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE MODELS ARE IN GOOD AGREEMENT WITH THIS SYSTEM.


...UPPER TROUGH CROSSING THE NORTHERN PLAINS/UPPER MIDWEST
SAT/SUN...

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

THE 00Z NAM IS A BIT OF A SLOWER AND DEEPER OUTLIER WITH THIS
SYSTEM. THE 00Z CMC IS THE MOST PROGRESSIVE SOLUTION. THE 00Z
GFS/00Z UKMET AND 00Z ECMWF ARE WELL CLUSTERED WITH THEIR
SOLUTIONS IN BETWEEN...AND A CONSENSUS OF THESE SOLUTIONS WILL BE
PREFERRED.


...UPPER TROUGH DROPPING SOUTH THROUGH BRITISH COLUMBIA ON SAT...

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

THE 00Z CMC GRADUALLY BECOMES A MODESTLY DEEPER AND MORE
PROGRESSIVE SOLUTION WITH THIS SYSTEM...WHEREAS THE 00Z NAM TENDS
TO ALSO BE SOMEWHAT DEEPER THAN THE MODEL CONSENSUS BUT IS A BIT
SLOWER. THE 00Z GFS/00Z UKMET AND 00Z ECMWF ALL CLUSTER TOGETHER
IN BETWEEN THE NAM AND CMC CAMPS. WILL PREFER THE GFS/UKMET/ECMWF
CLUSTER.


...UPPER TROUGH DIGGING SOUTH OFFSHORE BRITISH COLUMBIA BY MON...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: AVERAGE

THE NEXT IN A SERIES OF UPPER TROUGHS WILL DIG SOUTH FROM NEAR THE
GULF OF AK ON MON AND DOWN JUST OFFSHORE BRITISH COLUMBIA WHILE
APPROACHING THE PACIFIC NORTHWEST. THE 00Z NAM APPEARS TO BE A TAD
TOO PROGRESSIVE WITH THE SYSTEM. THE GLOBAL MODELS ARE IN
SUFFICIENT AGREEMENT THOUGH AT THIS POINT THAT A NON-NAM CONSENSUS
CAN BE PREFERRED FOR NOW.


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

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: AVERAGE

THE 00Z NAM TENDS TO HANG ONTO A SOMEWHAT STRONGER REFLECTION OF
THIS SYSTEM THROUGH THE PERIOD. WILL PREFER A NON-NAM CONSENSUS
GIVEN THE RELATIVELY GOOD AGREEMENT SEEN OUT OF THE GLOBAL MODELS
WITH THIS SYSTEM.


...LOW PRESSURE APPROACHING THE SOUTH FL AND THE KEYS BY SUN...

PREFERENCE: 00Z GFS...OR BLEND OF THE 00Z GEFS MEAN/12Z ECENS MEAN
CONFIDENCE: BELOW AVERAGE

A WEAK AREA OF LOW PRESSURE IS FORECAST TO APPROACH SOUTH FL OR
THE FL KEYS BY SUN...BEFORE THEN MOVING INTO THE EASTERN GULF OF
MEXICO. THE 00Z UKMET AND 00Z CMC ARE BOTH THE STRONGEST
SOLUTIONS...WITH THE 00Z NAM/00Z ECMWF AND ESPECIALLY THE 00Z GFS
ALL WEAKER. THE CMC TRACKS THIS SYSTEM FARTHEST TO THE
NORTH...WITH THE GFS FARTHEST TO THE SOUTH...ALTHOUGH THE NEW
ECMWF HAS TRENDED A BIT FARTHER SOUTH AND IS CLOSE TO THE GFS
THROUGH THIS PERIOD. BASED ON THE LEVEL OF DISORGANIZATION SEEN
WITH THE LOW CENTER CURRENTLY WHICH IS LOCATED IN BETWEEN THE
SOUTHEAST BAHAMAS AND THE NORTHEAST COAST OF CUBA...THE PREFERENCE
WILL BE TO LEAN TOWARD A SOMEWHAT WEAKER SOLUTION THAT IS LEFT OF
THE MODEL CONSENSUS. THIS WOULD BE CLOSE TO THE 00Z GFS WHICH IS
SUPPORTED BY THE 00Z GEFS MEAN AND 12Z ECENS MEAN. CONFIDENCE
AGAIN REMAINS LIMITED.


...WEAK MID LEVEL LOW CENTER NEAR THE WESTERN GULF COAST ON SUN...

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

THE MODELS INDICATE A WEAK MID LEVEL LOW CENTER AND ASSOCIATED
WEAK SURFACE LOW OR TROUGH APPROACHING THE WESTERN GULF COAST
STATES ON SUN. THE 00Z NAM TENDS TO BE A BIT STRONGER THAN THE
MODEL CONSENSUS WITH ITS MID LEVEL ENERGY. THE 00Z UKMET HAS A
FAIRLY WELL-DEFINED SURFACE LOW THAT IS NOT WELL SUPPORTED BY ANY
OTHER MODEL AT THIS TIME AND WILL BE DISMISSED. THE BETTER MODEL
CLUSTERING TENDS TO FAVOR A 00Z GFS/00Z ECMWF BLEND AND THIS WILL
BE THE PREFERENCE FOR NOW.

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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