Prognostic Meteorological Discussion
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FXUS10 KWNH 021906
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
206 PM EST MON MAR 02 2015

VALID MAR 02/1200 UTC THRU MAR 06/0000 UTC

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

12Z MODEL EVALUATION WITH FINAL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT
RANGE FORECASTS.


INITIAL UPPER LOW/TROUGH OVER CALIFORNIA REACHING THE CNTRL ROCKIES
  MON NIGHT
ASSOCIATED SFC LOW / COLD FRONT MOVING OUT INTO THE CNTRL PLAINS
  TUE MORNING AND THROUGH THE DAY ON TUE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS...12Z ECMWF BLEND
CONFIDENCE: AVERAGE

TIMING DIFFERENCES WITH THE REMNANT SHORTWAVE AS IT REACHES THE
CNTRL PLAINS EARLY TUE ALONG WITH THE ASSOCIATED COLD FRONT
EXTENDING WWD ACROSS THE ROCKIES HAVE CLOSED UP A BIT FROM THE 00Z
RUNS...BUT THEY STILL REMAIN.  THE 12Z NAM/CANADIAN REMAIN
SLIGHTLY SLOWER WITH THE SHORTWAVE COMPARED TO THE AGREEABLE 12Z
GFS/ECMWF.  GIVEN THE CHANGES MADE BY THE GFS AND LITTLE CHANGE
SHOWN BY THE ECMWF AT THE SURFACE...THE TWO MODELS WERE IN PRETTY
GOOD AGREEMENT AND THEIR ENSEMBLE AGREEMENT HAD GOTTEN BETTER.

BEYOND TUE...AN UPPER TROUGH MOVING ACROSS THE NRN PLAINS TAKES
OVER AND IMPACTS A COLD FRONT REACHING THE SOUTHEAST...DISCUSSED
IN THE NEXT SECTION.


UPPER TROUGH AXIS DROPPING OUT OF CANADA INTO THE N-CNTRL U.S. TUE
EVENTUAL STRONG COLD FRONT REACHING THE SOUTHEAST THU MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z ECMWF
CONFIDENCE: AVERAGE

THE 12Z NAM ACCELERATED THE AMPLIFYING WAVE AND ASSOCIATED SURFACE
FEATURES THAT FORMS OVER THE CNTRL PLAINS WED AND THE ASSOCIATED
SURFACE COLD...ALTHOUGH THE 12Z GFS WAS STILL FASTER THAN THE NAM.
 THIS DIFFERENCE WAS MAINLY CONFINED TO THE NEW ENGLAND PORTION OF
THE AREA BY WED.  THE UKMET AND CMC FRONTS/PRESSURES LAGGED THE EC
BY A BIT BY 05/00Z...BUT THE DIFFERENCES WERE NOT PARTICULARLY
GREAT...AND THOSE MODELS LAGGED THE GFS.  OVERALL...THERE WAS
LITTLE REASON TO CHANGE OUR EARLIER PREFERENCE.


SECONDARY SHORTWAVE ENERGY DIVING SOUTH OFF CALIFORNIA TODAY
CROSSING BACK INTO SOUTHWEST STATES LATE TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS / 12Z ECMWF BLEND
CONFIDENCE: A LITTLE BELOW AVERAGE

THE MODELS SHOW REASONABLY CLOSE AGREEMENT HERE AFTER TRENDING
TOWARD A COMMON MIDDLE GROUND...BUT WITH THE REMAINING
SPREAD...PREFER TO STAY TOWARD THE MIDDLE. THIS IS BEST
REPRESENTED BY THE 12Z GFS AND 12Z ECMWF...BOTH MODELS SHOWING
ONLY MINOR RUN TO RUN CHANGES SINCE THEIR 00Z RUNS YESTERDAY.


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

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

BANN

$$




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