991
FXUS10 KWNH 210443
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1143 PM EST WED NOV 20 2019
VALID NOV 21/0000 UTC THRU NOV 24/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...CLOSED LOW CROSSING THE FOUR CORNERS INTO THE PLAINS
FRIDAY/SATURDAY...
...POTENTIAL NORTHERN STREAM SHORTWAVE CROSSING THE NORTH-CENTRAL
U.S. FRIDAY NIGHT...
...SURFACE LOW MOVING FROM THE LOWER MISSISSIPPI VALLEY INTO THE
CENTRAL APPALACHIANS FRIDAY NIGHT INTO SATURDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z ECMWF/12Z UKMET/18Z GEFS MEAN
CONFIDENCE: SLIGHTLY BELOW AVERAGE
ANOMALOUS CLOSED UPPER LEVEL LOW OVER THE SOUTHWEST U.S. IS
EXPECTED TO MOVE INTO THE SOUTHERN/CENTRAL PLAINS OVER THE NEXT 48
HOURS AND EVENTUALLY PHASE WITH NORTHERN STREAM ENERGY TO DEEPEN
TROUGHING OVER THE EASTERN 2/3 OF THE CONUS INTO THIS WEEKEND.
MODEL GUIDANCE HAS COME INTO SLIGHTLY BETTER AGREEMENT THROUGH 48
HOURS WITH THE LARGE SCALE SYNOPTIC PATTERN, BUT CONFIDENCE
DECREASES AND MODEL SPREAD INCREASES FOR DAY 3. THE 00Z GFS HAS
TRENDED A BIT SLOWER WITH THE CLOSED UPPER LEVEL, AND ALLOWS IT TO
PHASE MORE WITH THE NORTHERN STREAM ENERGY BY SATURDAY. THIS
ALLOWS THE PARENT/INITIAL SURFACE LOW TO BE PULLED FURTHER
NORTHWEST ACROSS THE OHIO VALLEY COMPARED TO THE REST OF THE
GUIDANCE, WHICH SEEMS TO FAVOR A BIT LESS PHASING AND THEREFORE A
FASTER SOLUTION. LOOKING AT THE ENSEMBLE GUIDANCE, THERE IS BETTER
AGREEMENT BETWEEN THE ECENS AND GEFS MEANS, AND THE 18Z GEFS DOES
FAVOR A BIT FASTER SOLUTION. FOR THIS REASON, THE FAVORED BLEND
WILL INCORPORATE THE 12Z ECMWF, 12Z UKMET, AND THE 18Z GEFS MEAN
FOR NOW.
..REMAINDER OF THE CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND (EXCEPT NON-GFS BLEND PAC NW)
CONFIDENCE: AVERAGE
THERE IS RELATIVELY GOOD AGREEMENT WITH THE SYNOPTIC SETUP AND
EVOLUTION WITH THE SHORTWAVE TROUGH AND ASSOCIATED LOW PRESSURE
MOVING ACROSS THE MIDWEST AND NORTHEAST U.S. DURING THE FIRST
COUPLE DAYS OF THE FORECAST PERIOD. WHILE THERE ARE SOME SUBTLE
TIMING DIFFERENCES NOTED WITH THE SHORTWAVE, THOSE DIFFERENCES DO
NOT SEEM TO BE IMPACTING MUCH AT THE SURFACE AND SENSIBLE WEATHER.
AS SUCH, A GENERAL MODEL BLEND IS PREFERRED.
FOR THE SHORTWAVE TROUGH MOVING ACROSS THE PACIFIC NORTHWEST
FRIDAY, THE GFS IS MUCH FASTER THAN THE REST OF THE GUIDANCE AND
SHOULD BE DISCARDED ACROSS THAT REGION. OTHERWISE, THE REST OF THE
GUIDANCE IS SUFFICIENT AT THIS TIME.
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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