581
FXUS10 KWNH 180650
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
149 AM EST MON NOV 18 2019
VALID NOV 18/0000 UTC THRU NOV 21/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..OVERALL PATTERN ACROSS THE CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
LESS WEIGHT ON THE 00Z GFS AFTER 20.12Z
CONFIDENCE: AVERAGE
---06Z UPDATE---
THE 00Z CMC HAS TRENDED CLOSER TO THE OTHER MODELS WITH THE
SHORTWAVE DIGGING INTO THE GREAT LAKES LATER IN THE PERIOD, SO IT
COULD BE INCORPORATED INTO A MODEL BLEND. THE 00Z GFS STILL SEEMS
TO BE SPREADING HEIGHT FALLS OUT OF THE SOUTHWEST TOO FAST
COMPARED TO THE REMAINDER OF NEW 00Z MODEL RUNS. ONE OTHER NOTABLE
MODEL DIFFERENCE HAS DEVELOPED NEAR THE U.S.-CANADA BORDER WITH
SOME DISAGREEMENT ON THE LATITUDE OF A SHORTWAVE THAT WILL BE
GETTING SHEARED OUT OVER THE NORTHERN ROCKIES. THIS LEADS TO
DISAGREEMENT IN THE PLACEMENT OF A SWATH OF QPF. A COMPROMISE IS
PREFERRED AT THIS POINT.
---PREVIOUS DISCUSSION---
FOR THE NEXT SEVERAL DAYS, MODELS ARE IN REASONABLY GOOD AGREEMENT
WITH THE SYNOPTIC PATTERN, AND THE GENERAL PLACEMENT AND MAGNITUDE
OF QPF. SOME OF THE MORE SUBSTANTIAL SPREAD BY MID-WEEK WILL BE
RELATED TO TYPICAL TIMING BIAS, AS THE 00Z GFS AND ENSEMBLE
MEMBERS ARE FASTER WITH PULLING THE CLOSED UPPER LOW OUT OF THE
SOUTHWEST, WHILE THE 12Z ECMWF AND ENSEMBLE MEMBERS ARE SLOWER.
GIVEN THE STRENGTH OF THE UPPER LEVEL LOW, AND A RIDGE BUILDING
OVER THE TOP OF IT IN THE PACIFIC NORTHWEST, THE PREFERENCE IS TO
LEAN ON THE SLOWER SIDE OF THE MODEL SPREAD, WITH LESS WEIGHT ON
THE 00Z GFS BY WEDNESDAY.
THERE IS ALSO SOME TIMING SPREAD WITH A SHORTWAVE DIGGING FROM
CANADA INTO THE GREAT LAKES. IN THIS CASE, THE FASTEST MODEL IS
THE 12Z CMC, WITH MOST OF THE OTHER DETERMINISTIC MODELS SLOWER
AND IN BETTER AGREEMENT. THE PREFERENCE IS TO LEAN TOWARD MODEL
CONSENSUS FOR THIS WAVE, WITH LESS WEIGHT ON THE 12Z CMC BY
WEDNESDAY AS WELL.
THUS, THE OVERALL MODEL PREFERENCE COULD BE CHARACTERIZED BY A
GENERAL MODEL BLEND, SHIFTING TOWARD GREATER WEIGHT ON THE 12Z
ECMWF, 12Z UKMET, AND 00Z NAM BY WEDNESDAY, AND LESS WEIGHT ON THE
00Z GFS AND 12Z CMC.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
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