Prognostic Meteorological Discussion
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000
FXUS10 KWNH 080646
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
146 AM EST THU DEC 8 2016

VALID DEC 8/0000 UTC THRU DEC 11/1200 UTC

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

00Z FINAL MODEL EVALUATION INCLUDING PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


CLOSED LOW TRACKING TRACKING ACROSS SOUTHEAST CANADA THURSDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE MODELS INDICATE GOOD OVERALL MODEL AGREEMENT WITH THIS FEATURE
AND THUS A GENERAL MODEL COMPROMISE CAN BE USED FOR THE FORECAST.


LOW AMPLITUDE SHORTWAVE TRACKING FROM THE PLAINS TO THE EAST COAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE MODELS SHOW GOOD OVERALL SYNOPTIC AGREEMENT WITH THE MID-LEVEL
TROUGH AND ITS MASS FIELD CONFIGURATION.  ENOUGH AGREEMENT EXISTS
TO SUPPORT A GENERAL MODEL COMPROMISE AT THIS TIME.


SERIES OF STORM SYSTEMS IMPACTING THE WEST COAST BY FRIDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z GFS/00Z GEFS MEAN/12Z EC MEAN
CONFIDENCE: BELOW AVERAGE

THE TRICKIEST PART OF THE FORECAST NATIONWIDE DEALS WITH A SERIES
OF PACIFIC STORM SYSTEMS APPROACHING THE PACIFIC NORTHWEST COAST
TOWARDS THE END OF THE WEEK.  DIFFERENCES BEGIN EMERGING QUITE
EARLY IN THE FORECAST PERIOD, AS EARLY AS THURSDAY AFTERNOON.

THE 00Z GFS HAS TRENDED TOWARD THE GEFS/EC MEANS VERSUS YESTERDAY
REGARDING THE STRONG SURFACE LOW OVER THE NORTHEAST PACIFIC, ALONG
WITH THE UPSTREAM CLOSED LOW APPROACHING FROM THE WEST.
CURRENTLY, THE 00Z GFS LOOKS LIKE THE MOST REPRESENTATIVE OF THE
ENSEMBLE MEANS REGARDING HEIGHTS ALOFT AND THE SURFACE REFLECTION,
ALTHOUGH A FAIR AMOUNT OF SPREAD REMAINS IN THE ENSEMBLE MEMBERS
IN AN ELONGATED NW TO SE DIRECTION, KEEPING CONFIDENCE BELOW
AVERAGE.  THE 00Z ECMWF CONTINUES TO DEPICT TWO SEPARATE SURFACE
LOWS PIVOTING AROUND EACH OVER THIS REGION, WHEREAS THE OTHER
MODEL SOLUTIONS DEPICT ONE MAIN SURFACE LOW.  GIVEN THE POOR RUN
TO RUN CONTINUITY AND THE LATEST ENSEMBLE CLUSTERING, THE
PREFERENCE RESIDES WITH THE 00Z GFS AND THE ENSEMBLE MEANS.


SHORTWAVE EMERGING OVER THE NORTHERN PLAINS SATURDAY EVENING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z GFS/00Z UKMET COMPROMISE
CONFIDENCE: SLIGHTLY BELOW AVERAGE

DIFFERENCES NOTED WITH THE PACIFIC NORTHWEST STORM SYSTEMS
CONTINUE DOWNSTREAM ACROSS THE PLAINS WITH THE 00Z NAM CONTINUING
TO BE AMONG THE MOST AMPLIFIED SOLUTIONS ACROSS THE DAKOTAS AND
THE WESTERN HIGH PLAINS.  THE 00Z ECMWF, LIKE ITS EARLIER RUN,
CONTINUES TO BE A FLAT OUTLIER WITH THIS SYSTEM AND BARELY SHOWS
ANY DISTURBANCE AT ALL.  THE 00Z CMC ALSO APPEARS TO BE LESS
AMPLIFIED COMPARED TO THE EARLIER RUN AND MORE SIMILAR TO THE
ECMWF.



...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...

...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

HAMRICK

$$





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