Prognostic Meteorological Discussion
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000
FXUS10 KWNH 190631
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
230 AM EDT TUE AUG 19 2014

VALID AUG 19/0000 UTC THRU AUG 22/1200 UTC

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


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


DEEP-LAYERED CYCLONE MOVING TOWARDS THE DESERT SOUTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/ECMWF/NAM COMPROMISE
CONFIDENCE: AVERAGE

THE NON-GFS GUIDANCE HAS SHOWN SOME SIGNIFICANT FLIP-FLOPPING IN
THEIR FORECASTS CONCERNING THIS SYSTEM, LOWERING CONFIDENCE IN ANY
NON-GFS SOLUTION RIGHT OFF THE BAT.  TO BE FAIR, THE CYCLONE IS
DROPPING TOWARDS A COL POINT IN THE MID-LEVEL FLOW, WHICH NORMALLY
LEADS TO GREATER THAN AVERAGE UNCERTAINTY, MODEL GUIDANCE OR
OTHERWISE.  THE 00Z CANADIAN IS THE SLOWEST/MOST WESTERLY SOLUTION
AMONGST THE GUIDANCE THU/FRI -- ITS USUAL BIAS -- WHILE THE 00Z
UKMET IS THE QUICKEST -- ITS OLD BIAS.  A GFS/ECMWF/NAM COMPROMISE
IS PREFERRED WITH AVERAGE CONFIDENCE CONSIDERING THE POOR
DAY-TO-DAY CONTINUITY SEEN IN THE NON-GFS GUIDANCE.


TROUGH MOVING THROUGH THE NORTHERN CONTINENTAL DIVIDE
LEADING SHORTWAVE MOVING THROUGH THE DAKOTAS WED/THU
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/ECMWF COMPROMISE
CONFIDENCE: AVERAGE

THE 00Z UKMET IS WEAKER THAN THE OTHER GUIDANCE, INCLUDING THE 12Z
ECMWF/18Z GEFS MEANS, WITH THIS SYSTEM, WHILE THE 00Z CANADIAN/00Z
NAM ARE THE STRONGEST -- THEIR USUAL BIAS.  THE BEST 12Z GLOBAL
ENSEMBLE CLUSTERING WITH THIS SYSTEM SUPPORTS THE 00Z GFS/00Z
ECMWF SOLUTIONS, WHICH ARE PREFERRED WITH ONLY AVERAGE CONFIDENCE
CONSIDERING THE ABOVE AVERAGE SPREAD SEEN IN THE DETERMINISTIC AND
12Z GLOBAL ENSEMBLE GUIDANCE.


SYSTEM MOVING ACROSS THE GREAT LAKES & NORTHEAST
SURFACE LOW NEAR THE VIRGINIA CAPES FRIDAY MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-UKMET COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THIS MID-LEVEL SYSTEM IS EXPECTED TO PROGRESS UNDER THE BASE OF AN
INCREASINGLY STRONG AND QUASI-STATIONARY NORTHERN STREAM
RIDGE/CLOSED HIGH WITH TIME WHICH SHOULD KEEP IT STRONG AND
PROGRESSIVE.  THE 00Z UKMET FAILED IN THE STRENGTH DEPARTMENT
ALOFT, AND BECAUSE OF THIS, FALLS OUTSIDE THE 12Z GLOBAL ENSEMBLE
CLUSTERING BY FRIDAY MORNING WITH THE SURFACE LOW NEAR NC AND THE
VIRGINIA CAPES.  A NON-UKMET COMPROMISE IS ADVISED HERE WITH ABOVE
AVERAGE CONFIDENCE BASED UPON THE SYNOPTIC PATTERN IN WHICH THE
SYSTEM IS EMBEDDED.


...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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