Prognostic Meteorological Discussion
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000
FXUS10 KWNH 290643
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
242 AM EDT WED MAR 29 2017

VALID MAR 29/0000 UTC THRU APR 01/1200 UTC

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

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

...STRONG CLOSED LOW CROSSING THE CENTRAL/SOUTHERN PLAINS...
...ADVANCING EAST THROUGH THE MID MS/TN/OH VALLEYS BY THURS/FRI...
...ENERGY CROSSING THE MID-ATLANTIC BY FRI NIGHT...

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

THE 00Z NAM BECOMES A BIT SLOWER THAN THE MODEL CONSENSUS BY 36
HOURS AND BEYOND WITH THE STRONG SOUTHERN STREAM CLOSED LOW/TROUGH
AND ACCOMPANYING SURFACE LOW EJECTING ACROSS THE CENTRAL/SOUTHERN
PLAINS AND THEN ADVANCING EAST ACROSS THE MID MS/TN/OH VALLEYS
THURS AND FRI BEFORE CROSSING THE MID-ATLANTIC FRI NIGHT. THE 00Z
UKMET GRADUALLY BECOMES FOCUSED A TAD TOO FAR SOUTH AND WITH ITS
HEIGHT FALLS OVER THE OH/TN VALLEYS ALONG WITH ITS SURFACE LOW.
ALTHOUGH IT HAS TRENDED NORTH FROM ITS PREVIOUS RUN. STRONGER
MODEL CLUSTERING IS FOCUSED TOWARD THE 00Z GFS AND 00Z ECMWF WITH
SUPPORT ALSO FROM THE 00Z CMC. A BLEND OF THE GFS AND ECMWF WILL
BE SUGGESTED.


...TROUGH CROSSING THE NORTHERN TIER STATES WED THROUGH FRI...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GFS AND 00Z ECMWF
CONFIDENCE: AVERAGE

THE MODELS HAVE A WEAK NORTHERN STREAM TROUGH CROSSING THE
NORTHERN PLAINS/UPPER MIDWEST AND GREAT LAKES REGION WED THROUGH
FRI BEFORE THE ENERGY THEN SCOOTS INTO NORTHERN NEW ENGLAND BY
SAT. THE 00Z GFS AND 00Z ECMWF TEND TO HAVE THE BEST CLUSTERING AS
THE 00Z NAM GETS TO BE TOO WEAK AND 00Z UKMET A TAD TOO
PROGRESSIVE. A BLEND OF THE GFS AND ECMWF WILL BE PREFERRED AT
THIS POINT.


...SURFACE LOW CROSSING SOUTHERN BRITISH COLUMBIA WED...
...COLD FRONT MOVING ACROSS THE PACIFIC NORTHWEST...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE MODELS SHOW GOOD AGREEMENT WITH THIS SYSTEM AS IT MOVES INLAND
ON WED. A GENERAL MODEL COMPROMISE WILL BE PREFERRED.


...VIGOROUS TROUGH DIGGING INTO THE WEST ON THURS...
...STRONG CLOSED LOW OVER THE FOUR CORNERS BY FRI/SAT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

A STRONG UPPER TROUGH WILL BE DIGGING ACROSS THE PACIFIC NORTHWEST
ON THURS AND THEN AMPLIFYING VIGOROUSLY INTO A CLOSED LOW ACROSS
THE FOUR CORNERS REGION FRI AND SAT. THE 00Z NAM BY FRI AND SAT
BECOMES A TAD FASTER THAN THE GLOBAL MODELS IN EJECTING THE CLOSED
LOW OFF TO THE EAST. THE 00Z GFS AND 00Z ECMWF ARE WELL CLUSTERED
ALONG THROUGH THE PERIOD WITH TIMING...BUT EVENTUALLY THE GFS
BECOMES A BIT MORE ROBUST WITH ITS CLOSED LOW THAN ANY OTHER
MODEL. THE 00Z CMC LIKEWISE TENDS TO FAVOR THE MODESTLY STRONGER
GFS. THE GFS ALSO TENDS TO HAVE MORE LOW PRESSURE FARTHER ACROSS
THE CENTRAL ROCKIES AND INTO THE HIGH PLAINS COMPARED TO THE
REMAINING GUIDANCE. THE 00Z ECMWF APPEARS MOST REASONABLE AT THIS
POINT...AND WILL CONTINUE WITH THIS PREFERENCE.


...NORTHERN STREAM TROUGH/FRONT CROSSING THE NORTHERN PLAINS FRI...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

THE NEXT NORTHERN STREAM TROUGH WILL CROSS THE NORTHERN PLAINS BY
FRI ALONG WITH A WEAK COLD FRONT. THERE IS SUFFICIENT MASS FIELD
CLUSTERING DESPITE SOME MINOR TIMING/DEPTH DIFFERENCES TO GO WITH
A GENERAL MODEL COMPROMISE AT THIS POINT.

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

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

ORRISON

$$




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