Prognostic Meteorological Discussion
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000
FXUS10 KWNH 200521
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
120 AM EDT WED AUG 20 2014

VALID AUG 20/0000 UTC THRU AUG 23/1200 UTC

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

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


LOWER 48
~~~~~~~~
PREFERENCE: GFS/ECMWF/UKMET COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 12Z CANADIAN AND 00Z NAM ARE STRONG WITH ENERGY MOVING ACROSS
THE CENTRAL US/CANADIAN BORDER FRIDAY (THEIR USUAL BIASES), WITH
THE CANADIAN MORE PROGRESSIVE THAN THE OTHER GUIDANCE WITH
TROUGHING IN THE SOUTHWEST/CENTRAL ROCKIES ON FRIDAY, AND THE
CANADIAN SHALLOWER WITH A TROUGH/POSSIBLE CLOSED LOW EXPECTED
ACROSS THE NORTHERN GREAT BASIN (EVEN WHEN COMPARED TO THE 18Z
GEFS/12Z ECMWF ENSEMBLE MEAN SOLUTIONS) WHICH LIKELY LED TO
DOWNSTREAM ISSUES.  WITH STRONG RIDGING EXPECTED ACROSS THE
EASTERN PACIFIC, THE DOWNSTREAM TROUGH IN THE WEST SHOULD BE
STRONG, RULING OUT THE CANADIAN FROM CONSIDERATION.  SINCE THE
GFS/ECMWF/UKMET GUIDANCE IS SO AGREEABLE AT 500 HPA, 700 HPA, AND
THEIR SURFACE PRESSURE PATTERNS, PREFER A NON-CANADIAN COMPROMISE
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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