497
FXUS10 KWNH 160642
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
141 AM EST SAT NOV 16 2019
VALID NOV 16/0000 UTC THRU NOV 19/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..EAST OF THE CONTINENTAL DIVIDE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-ECMWF BLEND
CONFIDENCE: AVERAGE
---06Z UPDATE---
NO SIGNIFICANT CHANGE TO THE PRELIMINARY PREFERENCE. THE 00Z ECMWF
DID TREND CLOSER TO THE NORTHEAST COASTLINE WITH THE SURFACE LOW.
THEREFORE, IT COULD POTENTIALLY BE INCORPORATED INTO A MODEL BLEND
WITH LESS WEIGHT APPLIED NOW.
---PREVIOUS DISCUSSION---
THE TWO SIGNIFICANT SYNOPTIC FEATURES EAST OF THE ROCKIES ARE THE
DEVELOPING LOW OFF THE SOUTHEAST ATLANTIC COAST, AND THE TROUGH
THAT WILL BE DIGGING INTO THE PLAINS THIS WEEKEND. MODELS HAVE
GENERALLY CONVERGED ON THE SURFACE LOW EVOLUTION NEAR THE
CAROLINAS PRIOR TO SUNDAY (17.12Z), BUT BEGIN TO DIVERGE
THEREAFTER. THIS IS DUE TO VARIANCE WITH THE STRENGTH OF THE UPPER
LEVEL LOW OVER THE SOUTHEAST, AND THE TIMING OF THE UPSTREAM WAVE.
THE 12Z ECMWF IS NOTABLY SLOWER WITH THE UPSTREAM WAVE AS COMPARED
TO THE OTHER AVAILABLE MODELS, AND THIS CONTRIBUTES TO A SURFACE
LOW TRACK THAT IS FURTHER OFFSHORE AND WEAKER AS COMPARED TO THE
00Z NAM, 12Z CMC AND 12Z UKMET. THE 00Z GFS IS SLIGHTLY CLOSER TO
THE NEW ENGLAND COAST THAN THE ECMWF, BUT NOT AS FAR WEST AS THE
OTHER MODELS. THE PREFERENCE IS TO GO WITH A NON-ECMWF BLEND AS
THE STRONG CONSENSUS OF MOST MODELS IS FOR FASTER TIMING OF THE
UPSTREAM WAVE, AND THAT SHOULD ALLOW FOR A CLOSER APPROACH OF THE
SURFACE LOW TO THE COAST THAN THE ECMWF IS DEPICTING. THIS MAY
ALSO HAVE SOME IMPLICATIONS FOR LIGHT PRECIPITATION OVER THE GREAT
LAKES.
..WEST OF THE CONTINENTAL DIVIDE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-GFS BLEND
CONFIDENCE: AVERAGE
---06Z UPDATE---
NO CHANGE TO THE PRELIMINARY PREFERENCE.
---PREVIOUS DISCUSSION---
A STRONG TROUGH WILL APPROACH THE PACIFIC NORTHWEST ON MONDAY. THE
00Z GFS IS FURTHER NORTH WITH THE CORE OF THE ASSOCIATED MID-UPPER
LEVEL VORTICITY MAXIMUM THAN ALL THE OTHER AVAILABLE MODELS,
INCLUDING THE 18Z GEFS MEAN. THIS LEADS TO A NORTHWARD
DISPLACEMENT IN THE GFS PRECIPITATION FIELDS. THE PREFERENCE IS
FOR A NON-GFS BLEND ALONG THE WEST COAST.
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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