Prognostic Meteorological Discussion
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000
FXUS10 KWNH 190441
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1240 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 NAM/GFS EVALUATION WITH PRELIMINARY 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:  00Z GFS...12Z ECMWF...12Z CMC COMPROMISE
CONFIDENCE:  SLIGHTLY BELOW 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 00Z GFS AND 12Z ECMWF
APPEAR A REASONABLE MIDDLE GROUND WITH AGREEMENT FROM THE LATEST
GEFS/EC MEANS. THE 12Z CMC IS CLOSE TO THE GFS/ECMWF...BUT A BIT
SLOWER...WHICH COULD PLAY OUT GIVEN THE AMPLYFING NATURE OF THE
PATTERN BY MON/TUE OF NEXT WEEK.


SHORTWAVE ENTERING THE PACIFIC NW SAT REACHING MINNESOTA MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE:  CLOSEST TO THE 12Z ECMWF
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 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 18Z GEFS MEAN. THE 00Z CMC IS
A BIT SLOWER THAN PREFERRED AND A TAD TOO STRONG AS WELL...AGAIN
WITH THE ECMWF REPRESENTING THE BEST FIT FOR THIS SYSTEM.


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:  NON-00Z NAM 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 ON THE EDGE OF TIGHTLY CLUSTERED ENSEMBLE
MEMBERS. THE REMAINING MODELS MAKE UP 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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