442
FXUS10 KWNH 170706
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
306 AM EDT FRI JUL 17 2020
VALID JUL 17/0000 UTC THRU JUL 20/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z FINAL MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST
CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...LONG WAVE TROUGH CROSSING THE NORTH CENTRAL US INTO EASTERN
CANADA THROUGH FRI WITH AN ACCOMPANYING SURFACE COLD FRONT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THERE EXISTS LITTLE SPREAD AMONG THE GLOBAL MODELS IN DEPICTING
THE MID-LEVEL TROUGH AND ASSOCIATED SURFACE FRONT MOVING ACROSS
THE NORTHERN TIER THROUGH TODAY AND OFFSHORE THE NORTHEAST
TONIGHT. WITH LITTLE SPREAD AMONG THE GUIDANCE, A GENERAL MODEL
BLEND IS PREFERRED.
...LONG WAVE TROUGH CROSSING THE PACIFIC NORTHWEST TODAY, MOVING
INTO SOUTH CENTRAL CANADA BY SAT, THEN CLIPPING THE NORTHERN
PLAINS INTO UPPER GREAT LAKES BY SUN...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND, LESS WEIGHT ON THE 00Z NAM/CMC
CONFIDENCE: AVERAGE
07Z UPDATE: 12Z NON-NCEP SUITE REMAINS GENERALLY WELL CLUSTERED TO
THE ENSEMBLES AND NCEP MEMBERS. NOTE A SUBTLE HEIGHT DISCREPANCY
ALONG THE EAST COAST IN THE CORE OF THE UPPER RIDGE WHERE THE CMC
IS A BIT WARMER ON D2 AND D3. THE DIFFERENCE OVERALL IS
NEGLIGIBLE, BUT WITH SUCH GOOD AGREEMENT OTHERWISE, A LITTLE LESS
WEIGHT ON THE CMC SEEMS PRUDENT. OTHERWISE, NO CHANGES TO THE
PRIOR BLEND.
PREVIOUS DISCUSSION:
AS AN EXPANSIVE RIDGE ENVELOPS MUCH OF THE CONUS, FLOW ATOP IT AND
ACROSS THE NORTHERN TIER AND SOUTHERN CANADA BECOMES LOW AMPLITUDE
AND FAST. WITHIN THIS FLOW, A SHORTWAVE DROPPING INTO THE PACIFIC
NORTHWEST TODAY WILL RACE EASTWARD TO THE GREAT LAKES BY SUNDAY,
DRAGGING A COLD FRONT BENEATH IT. WITH THE RIDGE TO THE SOUTH
PREVENTING MUCH AMPLIFICATION OF ANY FEATURES, THE DEEPER NAM THE
LATTER HALF OF D3 BOTH WITH ITS MID-LEVEL ENERGY AND THE SURFACE
LOW WHICH DEVELOPS ALONG THE FRONT SEEM OVERDONE, AND ARE OUT OF
TOLERANCE WITH THE GLOBAL CONSENSUS BY THE END OF THE FORECAST
PERIOD. OTHERWISE, THERE EXISTS LITTLE SPREAD OTHER THAN SMALL
AMPLITUDE PERTURBATIONS WITHIN THE FLOW, SUCH THAT A GENERAL
COMPROMISE THROUGH 48 HOURS AND A NON-NAM BLEND ON D3 SEEMS
REASONABLE.
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.
WEISS
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