234
FXUS10 KWNH 061831
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
231 PM EDT THU AUG 06 2020
VALID AUG 06/1200 UTC THRU AUG 10/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
OVERALL WEATHER PATTERN ACROSS THE CONTINENTAL U.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
18Z UPDATE...
AFTER REVIEWING THE 12Z NON-NCEP MODELS, THERE ARE NO CHANGES TO
THE PREFERRED PREFERENCE OF A MULTI MODEL BLEND. THE MINOR
DIFFERENCES REMAIN WITH THE PLACEMENT OF THE CLOSED MID LEVEL LOW
OVER CENTRAL CANADA AND THE PLACEMENT OF SURFACE LOW(S) ALONG THE
FRONTAL BOUNDARY EXTENDING FROM THE UPPER MS VALLEY INTO THE
CENTRAL PLAINS. HOWEVER, THE NEW MODEL INFORMATION SUPPORTS A
GENERAL MODEL BLEND TO MITIGATE THE DIFFERENCES.
PREVIOUS DISCUSSION...
FOR THE MOST PART, THERE IS GENERALLY GOOD MODEL AGREEMENT ACROSS
THE CONUS INTO CANADA THROUGH 10/00Z. THERE ARE SOME MODEL
DIFFERENCES IN THE PLACEMENT AND STRENGTH OF THE CLOSED MID LEVEL
LOW TRACKING ACROSS SASKATCHEWAN INTO MANITOBA BETWEEN 08/00Z AND
10/00Z. THOUGH THE DIFFERENCES ARE RELATIVELY MINOR, THEY DO HAVE
RAMIFICATIONS DOWNSTREAM, AS SHORT WAVE ENERGY EJECTED FROM THE
BASE OF THE CLOSED MID LEVEL LOW TRACK THROUGH THE FAST MID LEVEL
FLOW ACROSS THE NORTHERN MID ATLANTIC AND SOUTHERN NEW ENGLAND,
ESPECIALLY AFTER 09/00Z. THOUGH THERE IS SOME SPREAD IN THE TIMING
OF THE SHORT WAVES, THAT WOULD BE EXPECTED IN THE FAST MID LEVEL
FLOW. OVERALL, A GENERAL MODEL BLEND SHOULD SUFFICE, ALLOWING THE
TIMING DIFFERENCES TO BE MUTED TO SOME DEGREE.
THERE IS ALSO SOME MODEL SPREAD WITH THE DEVELOPMENT OF A SURFACE
WAVE ON A FRONT EXTENDING FROM THE UPPER MS VALLEY INTO THE
CENTRAL HIGH PLAINS AFTER 09/00Z. THE SPREAD MAY BE TIED TO THE
SHORT WAVE TIMING IN THE FAST MID LEVEL FLOW, BUT THE DIFFERENCES
IN THE SURFACE LOW PLACEMENT APPEAR TO BE TYPICAL FOR A DAY 2/DAY
3 FORECAST, SO A MODEL BLEND SHOULD WORK HERE AS WELL.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
THIS PRODUCT WILL TERMINATE AUGUST 15, 2020:
WWW.WEATHER.GOV/MEDIA/NOTIFICATION/PDF2/SCN20-58PMDHMD_TERMINATION.
HAYES
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