Prognostic Meteorological Discussion
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000
FXUS10 KWNH 190643
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
243 AM EDT SAT APR 19 2014

VALID APR 19/0000 UTC THRU APR 22/1200 UTC

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


00Z MODEL EVALUATION WITH FINAL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT
RANGE FORECASTS.

NOTE THAT OUTPUT FROM THE 12Z UKMET APPERS TO BE CORRUPTED AFTER
12Z SUNDAY...F048...AND WILL NOT BE INCLUDED IN THIS VERSION OF
THE PMDHMD.


DEEP LAYERED TROUGH APPROACHING THE WEST COAST INTO TUE MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE:  NON-00Z NAM COMPROMISE
CONFIDENCE:  AVERAGE

THE GUIDANCE IS IN GOOD AGREEMENT WITH THIS SYSTEM UNTIL SUN NIGHT
WHEN SHORTWAVE DETAIL DIFFERENCES BEGIN TO APPEAR...NOTED IN THE
00Z NAM OFF THE PAC NW MON AFTERNOON. THE REMAINING MODELS ARE IN
REASONABLY GOOD AGREEMENT NOW THAT THE 00Z ECMWF/UKMET/CMC HAVE
SHOWN SOME CONVERGENCE TOWARD THE 00Z GFS. THE AMPLYFING NATURE OF
THE PATTERN BY MON/TUE OF NEXT WEEK COULD CAUSE THE UPPER TROUGH
TO BE A BIT SLOWER THAN THIS CONSENSUS BUT THERE IS REASONABLY
GOOD ENSEMBLE AGREEMENT...WITH JUST A FEW SLOWER AND FASTER
ENSEMBLE MEMBERS.


SHORTWAVE ENTERING THE PACIFIC NW SAT REACHING MINNESOTA MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE:  00Z ECMWF/UKMET BLEND
CONFIDENCE:  AVERAGE

THE 12Z NAM APPEARS A BIT TOO FAST BASED ON THE REMAINING MODEL
CONSENSUS...NOTED MOSTLY BY MID-DAY MON. THE REMAINING
DETERMINISTIC MODELS AND ENSEMBLE GUIDANCE SUPPORTS SOMETHING
SLOWER...WITH THE ECMWF AND UKMET REPRESENTING A REASONABLE
DEPICTION IN THE MIDDLE OF THE SPREAD CONCERNING THE UPPER TROUGH
ALOFT AND THE SURFACE LOW. THE 00Z GFS APPEARS TOO WEAK WITH THE
UPPER TROUGH...AND IS NOT SUPPORTED BY THE 00Z GEFS MEAN. THE 00Z
CMC IS A CLOSE SECOND AND IS JUST A BIT SLOWER/NORTH THAN
PREFERRED.


WEAKENING MID-LEVEL SHORTWAVE PASSING BY NRN MAINE SUN NIGHT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE:  GENERAL MODEL COMPROMISE
CONFIDENCE:  ABOVE AVERAGE

THE MODELS SHOW REASONABLE AGREEMENT HERE...WITH A GENERAL MODEL
COMPROMISE PREFERRED TO IRON OUT SMALLER SCALE DETAIL DIFFERENCES.


DEEP CYCLONE MOVING OFFSHORE THE SOUTHEAST THIS WEEKEND
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE:  00Z GFS/ECMWF/UKMET COMPROMISE
CONFIDENCE:  ABOVE AVERAGE

THE 00Z NAM IS SLOWER COMPARED TO THE REMAINING DETERMINISTIC
MODEL CONSENSUS...BY JUST ENOUGH...TO PREVENT IT FROM BEING
PREFERRED. THE NAM IS ALSO ON THE EDGE OF TIGHTLY CLUSTERED
ENSEMBLE MEMBERS. THE 00Z CMC IS DISPLACED OFF TO THE SOUTHEAST
WITH THE MAIN MID-LEVEL VORTICITY MAX OFF OF THE SOUTEHAST COAST
FROM THE CONSENSUS AND HAS AN EXTRA/STRONGER SURFACE LOW CLOSE TO
THE NORTH CAROLINA COAST WHICH IS NOT SUPPORTED IN THE REMAINING
MODELS. THE GFS/ECMWF/UKMET COMBO REPRESENT A GOOD COMPROMISE.


SYSTEM MOVING FROM THE SOUTHWEST INTO THE MISSISSIPPI VALLEY BY MON
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE:  GENERAL MODEL COMPROMISE
CONFIDENCE:  AVERAGE

THE MODELS SHOW REASONABLE AGREEMENT HERE...WITH A GENERAL MODEL
COMPROMISE PREFERRED TO IRON OUT SMALLER SCALE DETAIL DIFFERENCES.


...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...
...500 MB FORECASTS AT www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

OTTO

$$





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