610
FXUS10 KWNH 261946
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
345 PM EDT THU MAR 26 2020
VALID MAR 26/1200 UTC THRU MAR 30/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z FINAL MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...MID-LEVEL TROUGH OVER THE SOUTHWEST BECOMING A LOW AS IT TRACKS
NORTHEAST FROM COLORADO ACROSS CENTRAL PLAINS AND THE GREAT LAKES
FRI NIGHT THROUGH SUN MORNING...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z ECMWF/00Z ECENS/12Z GEFS BLEND WITH SOME 12Z GFS
ON DAY 2 AND 12Z NAM ON DAY 3
CONFIDENCE: AVERAGE
THERE WAS A GENERAL SLOWING TREND AMONG ALL 12Z GUIDANCE WITH THIS
SYSTEM ON BOTH DAYS 2 AND 3 OWING TO UNCERTAINTY ABOUT HOW THE
SYSTEM WILL CLOSE AND TRACK AFTER CROSSING THE CENTRAL ROCKIES
FRIDAY NIGHT. THE 12Z UKMET AND CMC ARE STILL THE FIRST MODELS TO
CLOSE AT 500MB WHICH MAKES THEN SLOWER. HOWEVER, THE 12Z UKMET
SLOWED EVEN FURTHER, SO IT IS THE BIGGEST OUTLIER WHILE THE 12Z
CMC IS QUITE CLOSE TO THE 00Z RUN AND CLOSER TO THE ECMWF WHICH IS
A LITTLE SLOWER WITH THE 12Z. THE 12Z NAM IS STILL THE LAST TO
CLOSE THE LOW IN THE MID-LEVELS, SO IT IS THE FASTEST SOLUTION ON
DAY 2, BUT SLOWS ENOUGH TO COME WELL INTO THE FOLD ON DAY 3. THE
12Z ECMWF IS STILL WITHIN THE 00Z ENSEMBLE MEAN AND IS THE
PREFERRED MODEL SOLUTION. THE 12Z GEFS MEAN TRACKS RIGHT ALONG
WITH THE EMCWF/ECENS AS THE 06Z DID AND IS NOT AS FAR EAST AS THE
OPERATIONAL 12Z GFS (WHICH HAS A DIFFERENT MODEL CORE THAN THE
GEFS) ON DAY 3. THE 12Z GFS DID SLOW JUST A BIT COMPARED TO THE
06Z, SO IT IS ABLE TO BE USED ON DAY 2 (SIMILAR PRECIP PATTERN TO
THE PREFERENCE), BUT REMAINS FLATTER/FARTHER EAST WITH THE TRACK
ON DAY 3.
...SHORTWAVE AND SURFACE COLD FRONT APPROACHING PACIFIC NORTHWEST
SAT AND SHIFTING DOWN THE CALIFORNIA COAST THROUGH SUN...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/ECMWF/UKMET BLEND
CONFIDENCE: AVERAGE
THERE IS GOOD MODEL AGREEMENT ON THE TROUGH SHIFTING SOUTHEAST OFF
THE PACIFIC NORTHWEST BEFORE REACHING THE CA COAST ON DAY 3. THE
MAIN DIFFERENCES ON DAY 3 ARE WITH TIMING AND STRENGTH OF THE
REINFORCING SHORTWAVE TROUGH THAT AMPLIFIES THE TROUGH DOWN THE CA
COAST. THE 12Z ECMWF IS THE NOT AS POSITIVELY TILTED THROUGH DAY 3
AS THE 00Z AND THE 12Z CMC/UKMET BOTH SLOWED THEIR EASTWARD
EJECTION OVER CA BY QUITE A BIT. IN FACT THE 12Z CMC IS NOW THE
SLOWEST SOLUTION HAVING BEEN THE FASTEST AT 00Z. THAT LEAVES THE
12Z NAM AS THE MOST EASTWARD PROGRESSIVE AND THE ONLY OUTLIER. THE
QPF AMONG THE LATEST GFS ECMWF AND UKMET ARE PRETTY SIMILAR GIVEN
THEIR SIMILAR PATTERNS, SO THEY ARE PREFERRED AT THIS TIME.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
JACKSON
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