Prognostic Meteorological Discussion
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000
FXUS10 KWNH 030435
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1234 AM EDT MON AUG 03 2015

VALID AUG 03/0000 UTC THRU AUG 06/1200 UTC

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

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


DEEP CYCLONE MOVING INTO BRITISH COLUMBIA
TROUGH MOVES INTO THE NORTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CANADIAN COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 12Z CANADIAN SHOWED A MORE SOUTHERLY 500 HPA CYCLONE MOVING
ALONG THE US/CANADIAN BORDER -- ONE OF ITS USUAL BIASES.  WITH THE
REMAINDER OF THE GUIDANCE IN GOOD AGREEMENT WITH EACH OTHER AND
THE 18Z GEFS/12Z ECMWF ENSEMBLE MEANS, FAVOR A COMPROMISE OF THE
12Z ECMWF/12Z UKMET/00Z NAM/00Z GFS WITH ABOVE AVERAGE CONFIDENCE.


SHORTWAVE CROSSING THE ROCKIES/PLAINS
SURFACE LOW CROSSING THE MS RIVER WED PM
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NAM/ECMWF COMPROMISE
CONFIDENCE: AVERAGE

THE 12Z UKMET ATTEMPTS TO FORM A WARM CORE CONVECTIVE CYCLONE
WHICH DEEPENS A BIT AS IT MOVES INTO MO -- ONE OF ITS RECENT
BIASES.  THE 12Z CANADIAN IS PRONE TO SUCH FEEDBACK AS WELL, BUT
ITS CENTRAL PRESSURE IS MORE RESPECTABLE.  THE PROBLEM WITH THE
CANADIAN IS THAT IT IS ON THE SLOW SIDE OF THE 12Z GLOBAL ENSEMBLE
SPREAD.  A COMPROMISE OF THE 00Z NAM/12Z CANADIAN SPLITS THE
DIFFERENCE SEEN IN THE 18Z GEFS/12Z ECMWF ENSEMBLE MEAN SOLUTIONS,
AND IS PREFERRED WITH AVERAGE CONFIDENCE.


LOW PRESSURE MOVING FROM FL UP THE CAROLINA COAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z GFS
CONFIDENCE: ABOVE AVERAGE

THE 12Z CANADIAN/12Z UKMET ARE THE MOST BULLISH ON THIS SYSTEM --
WHICH IS THEIR BIAS.  HOWEVER, THEY OUTPACE THE REMAINDER OF THE
GUIDANCE HERE.  FOR THE MOMENT, THE 00Z GFS APPEARS TO BE MOST
FAVORED BY THE 12Z GLOBAL ENSEMBLE GUIDANCE, SO IT IS PREFERRED
WITH ABOVE AVERAGE CONFIDENCE.


DEEP CYCLONE MOVING THROUGH EASTERN CANADA
TROUGH MOVING THROUGH THE NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE GUIDANCE SHOWS GOOD AGREEMENT WITH THIS SYSTEM


...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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