Prognostic Meteorological Discussion
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000
FXUS10 KWNH 300634
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
234 AM EDT TUE JUN 30 2015

VALID JUN 30/0000 UTC THRU JUL 03/1200 UTC

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

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


SHORTWAVE/LOW MOVING THROUGH MS VALLEY EARLY FRI
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS
CONFIDENCE: AVERAGE

THERE IS SPREAD IN THE GUIDANCE WITH THIS SYSTEM AS THE 00Z
UKMET/00Z ECMWF ARE VERY WEAK AND THE 00Z CANADIAN IS THE
STRONGEST -- ITS USUAL BIAS.  WHILE NORMALLY GOING STRONGER ALOFT
EAST OF A CLOSED HIGH CAN BE A SHREWD MOVE, A WEAK UPSTREAM
SHORTWAVE MOVING BY MONTANA THURSDAY NIGHT MUDDIES THE THE
PICTURE.  THE 12Z GLOBAL ENSEMBLE CLUSTERING MOST FAVORED THE 00Z
GFS, WHICH IS PREFERRED WITH AVERAGE CONFIDENCE.


SHORTWAVE/LOW MOVING FROM THE SOUTHERN PLAINS TO THE
VIRGINIA CAPES THURSDAY NIGHT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/UKMET/ECMWF COMPROMISE
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

WHILE THE 00Z NAM AND 00Z ECMWF ARE QUICK IN MOVING THIS CYCLONE
OUT TO SEA DUE TO QUICKER MOVING UPPER LEVEL SHORTWAVES, THE ECMWF
HAS SHOWN A SHIFT BACK TOWARDS THE SLOWER 00Z GFS/00Z CANADIAN
GUIDANCE.  THE 00Z GEFS/12Z ECMWF ENSEMBLE MEAN SOLUTIONS FAVOR
THE SLOWER NON-NAM CONSENSUS.  OF THESE, THE 00Z UKMET/00Z GFS/00Z
ECMWF WERE A REASONABLE MATCH TO THE 12Z GLOBAL ENSEMBLE LOW
CLUSTERING, SO THEY ARE PREFERRED WITH SLIGHTLY ABOVE AVERAGE
CONFIDENCE.


MID-LEVEL CYCLONE WEAKENING OVER MEXICO
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE GUIDANCE SHOWED REASONABLE AGREEMENT WITH THIS FEATURE.


CYCLONE LIFTING FROM THE GREAT LAKES INTO
QUEBEC & ITS TRAILING COLD FRONT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM COMPROMISE
CONFIDENCE: ABOVE AVERAGE

WHILE THE NAM IS SLOW WITH THE CYCLONE MOVEMENT, THIS DOES NOT
SEEM TO IMPACT ITS FRONTAL PROGRESSION THROUGH THE NORTHEAST.
NEVERTHELESS, PREFER A NON-NAM COMPROMISE HERE WITH ABOVE AVERAGE
CONFIDENCE.


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

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

ROTH
$$





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