Prognostic Meteorological Discussion
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000
FXUS10 KWNH 240658
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
257 AM EDT FRI MAR 24 2017

VALID MAR 24/0000 UTC THRU MAR 27/1200 UTC

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

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

...CLOSED LOW DIVING THROUGH EASTERN CANADA BY SAT MORNING...
...COLD FRONT ADVANCING DOWN ACROSS THE GREAT LAKES/NORTHEAST...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

DIFFERENCES AT THIS POINT ARE RATHER MODEST WITH THE EVOLUTION OF
THE STRONG UPPER LOW MOVING INTO EASTERN CANADA AND THE COLD FRONT
SWEEPING SOUTHEAST ACROSS THE GREAT LAKES AND NORTHEAST. A GENERAL
MODEL COMPROMISE WILL BE PREFERRED AT THIS TIME.


...CLOSED LOW EVOLUTION OVER THE CENTRAL PLAINS FRI...
...ENERGY CROSSING THE MID MS/OH VALLEYS THROUGH SAT...
...SYSTEM WEAKENING INTO THE GREAT LAKES BY SUN/MON...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: AVERAGE

THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE 00Z
CYCLE...WITH THE ECMWF HAVING TRENDED A LITTLE MORE PROGRESSIVE
AND RATHER CLOSE TO THE MODEL CONSENSUS. THE CMC WHICH HAD BEEN
MORE PROGRESSIVE AND FARTHER NORTH WITH ENERGY REACHING THE GREAT
LAKES REGION IS NOW A BIT SLOWER. HOWEVER...THE NAM AT THIS POINT
DOES APPEAR TO BE TOO FAST IN LIFTING ITS SURFACE WAVE NORTHEAST
OUT OF THE MID MS VALLEY AND ACROSS THE GREAT LAKES REGION. THE
GLOBAL MODELS ARE WELL CLUSTERED IN BEING A LITTLE SLOWER AND
SOUTHWEST OF THE NAM SOLUTION. WILL PREFER A NON-NAM CONSENSUS AS
A RESULT.


...NORTHERN STREAM TROUGH/COLD FRONT CROSSING THE NORTHWEST
THROUGH FRI...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THERE ARE ONLY MINOR TIMING DIFFERENCES WITH THIS SYSTEM AND ITS
ASSOCIATED COLD FRONT...THUS A GENERAL MODEL COMPROMISE IS
PREFERRED TO SMOOTH OUT THESE SMALLER SCALE DIFFERENCES.


...SOUTHERN STREAM COMPONENT OF UPPER LEVEL TROUGH OVER THE WEST
ON SAT...
...ENERGY EJECTING INTO THE CENTRAL/SOUTHERN PLAINS SUN
NIGHT/MON...

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

THE MODELS CLUSTER TOGETHER VERY WELL WITH THE TIMING AND DEPTH OF
THE SOUTHERN STREAM TROUGH INITIALLY CROSSING CA ON FRI AND MOVING
INTO GREAT BASIN ON SAT. HOWEVER...AFTER ABOUT 36 HOURS...THE 00Z
CMC BECOMES SLOWER THAN THE MODEL CONSENSUS WITH ITS EASTWARD
PROGRESSION. IN TIME THE 00Z GFS BEGINS TO TREND A BIT STRONGER
THAN THE MODEL CONSENSUS AT THE SURFACE AND ALOFT...AND ESPECIALLY
BY SUN NIGHT/MON AS THE SYSTEM CROSSES OUT THROUGH THE
CENTRAL/SOUTHERN PLAINS. THE LATEST GEFS MEAN AND ECENS MEAN TEND
TO FAVOR THE SLIGHTLY WEAKER CONSENSUS BY LATER SUN/MON. WILL
SUGGEST LEANING TOWARD A BLEND OF THE 00Z NAM/UKMET AND ECMWF AT
THIS TIME WHICH AS A BLEND MOST CLOSELY MATCHES THE MODEL
CONSENSUS.


...UPPER TROUGH/COLD FRONT REACHING THE WEST COAST SUN EVENING...

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

THE MODELS BRING THE NEXT UPPER TROUGH AND ASSOCIATED COLD FRONT
ACROSS THE WEST COAST BY SUN EVENING WITH THE TROUGH THEN MOVING
INLAND ON MON. THE 00Z NAM IS A TAD FASTER WITH THE FRONT VERSUS
THE 00Z GLOBAL MODELS AS IT APPROACHES AND ARRIVES ALONG THE WEST
COAST. BY LATER SUN AND MON...WITH RESPECT TO THE UPPER
TROUGH...THE 00Z NAM AND 00Z CMC BOTH APPEAR TO BE A TAD TOO
FAST...WITH PERHAPS THE 00Z ECMWF EDGING A LITTLE TOO SLOW. WILL
COMPROMISE BY SUGGESTING A BLEND OF THE 00Z GFS/UKMET AND ECMWF AT
THIS POINT.

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

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

ORRISON

$$




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