Prognostic Meteorological Discussion
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000
FXUS10 KWNH 080503
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1202 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 NAM/GFS/UKMET 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.  THE 12Z CMC ADJUSTED
SOME TOWARD THE CONSENSUS COMPARED TO LAST NIGHT`S RUN, EVEN
THOUGH IT INDICATES A SLIGHTLY DEEPER TROUGH TOWARDS THE END OF
THE PERIOD.  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/18Z 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.

COMPARED TO YESTERDAY, THE 00Z GFS HAS TRENDED TOWARD THE GEFS/EC
MEANS REGARDING THE STRONG SURFACE LOW OVER THE NORTHEAST PACIFIC,
ALONG WITH THE UPSTREAM CLOSED LOW APPROACHING FROM THE WEST.
CURRENTLY, THE 00Z GFS LOOKS THE MOST REPRESENTATIVE OF THE
ENSEMBLE MEANS REGARDING HEIGHTS ALOFT AND THE SURFACE REFLECTION,
ALTHOUGH A FAIR AMOUNT OF SPREAD REMAINS IN THE ENSEMBLES, KEEPING
CONFIDENCE BELOW AVERAGE.  GIVEN THE POOR RUN TO RUN CONTINUITY
AND THE LATEST ENSEMBLE CLUSTERING AWAY FROM THE 12Z ECMWF, 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 AMONG THE
MOST AMPLIFIED ACROSS THE DAKOTAS THE PLAINS.  THE 12Z ECMWF
CONTINUES TO BE A FLAT OUTLIER WITH THIS SYSTEM.  THE 12Z CMC
APPEARS TOO FAST WITH THE SPEED OF THE TROUGH.



...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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