Prognostic Meteorological Discussion
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FXUS10 KWNH 021655
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1154 AM 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...00Z 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 AND 00Z CMC REMAIN
SLIGHTLY SLOWER WITH THE SHORTWAVE COMPARED TO THE AGREEABLE 12Z
GFS AND 00Z ECMWF. WHILE THERE WAS SOME DISAGREEMENT BETWEEN THE
MODELS AND THEIR RESPECTIVE ENSEMBLES...THE AGREEMENT BETWEEN THE
GFS/ECMWF AGREE PRETTY WELL WITH THEIR ENSEMBLE MEANS.  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: 00Z ECMWF
CONFIDENCE: A LITTLE BELOW 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
NAME.  THE SREF/GEFS/EC MEANS SUGGEST THAT THE GFS IS TOO WEAK
WITH A SOUTHEAST UPPER RIDGE WHICH ALLOWS THE COLD FRONT TO MORE
QUICKLY PROGRESS SOUTH AND EAST WHILE THE 02/00Z ECMWF HAS
REMAINED FAIRLY STEADY IN THE TREATMENT OF THE WAVE AND SURFACE
FEATURES.  THUS WILL CONTINUE TO SUGGEST A SOLN CLOSE TO THE
02/00Z ECMWF ALTHOUGH KEEPING IN MIND THAT THE CURRENT ENSEMBLE
MEANS SUPPORT A FASTER SOLUTION THAN THE SLOWER NAM/UKMET BUT
ENSEMBLE SPREAD REMAINS LARGE WHICH LOWERS CONFIDENCE.


SECONDARY SHORTWAVE ENERGY DIVING SOUTH OFF CALIFORNIA TODAY
CROSSING BACK INTO SOUTHWEST STATES LATE TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS / 00Z 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 00Z 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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