514
FXUS10 KWNH 311646
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1245 PM EDT TUE MAR 31 2020
VALID MAR 31/1200 UTC THRU APR 4/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH PRELIMINARY PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SOUTHEAST U.S. SURFACE LOW AND SHORTWAVE TROUGH
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM COMPROMISE
CONFIDENCE: HIGH
THE SURFACE LOW CURRENTLY TRACKING EASTWARD ACROSS THE SOUTHEAST
WILL EMERGE OVER THE WESTERN ATLANTIC TUESDAY NIGHT AND TRACK OUT
TO SEA AND NORTH OF BERMUDA. DIFFERENCES ARE RELATIVELY MINOR
WITH THIS SYSTEM FOR THE MOST PART. HOWEVER, THE 12Z NAM WAS THE
FARTHEST NORTHWEST WITH THE SURFACE LOW WHICH TRACKS ACROSS THE
WESTERN ATLANTIC AND MORE AMPLIFIED ALOFT COMPARED TO THE OTHER
MODELS. THE PREFERENCES IS TOWARD A NON-NAM CONSENSUS TO ACCOUNT
FOR THE GOOD AGREEMENT OF THE OTHER MODELS.
BROAD UPPER LEVEL GYRE OVER NORTHWEST WITH NORTHERN PLAINS
SHORTWAVE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/00Z ECMWF/00Z UKMET BLEND
CONFIDENCE: MODERATE
AN UPPER LEVEL LOW OVER SOUTHWEST CANADA WILL REMAIN NEARLY
ANCHORED IN PLACE FOR THE NEXT FEW DAYS, WITH A COUPLE OF
SHORTWAVES PIVOTING AROUND IT. THE FIRST SHORTWAVE PERTURBATION
WILL PIVOT NORTHEASTWARD ACROSS MONTANA AND NORTH DAKOTA ON
WEDNESDAY, SUSTAINING A SURFACE LOW ACROSS THE DAKOTAS. THE MAIN
MODEL DIFFERENCE HERE IS WITH THE 12 NAM, INDICATING A MUCH MORE
AMPLIFIED SOLUTION BY 00Z THURSDAY, AND THE 00Z CMC A TAD SLOWER
WITH THE TRAILING COLD FRONT.
SHORTWAVE TRACKING ACROSS INTERMOUNTAIN WEST BY END OF THE WEEK
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z UKMET/ECMWF BLEND
CONFIDENCE: LOW-MODERATE
THE SECOND SIGNIFICANT SHORTWAVE PIVOTING AROUND THE UPPER LEVEL
GYRE WILL CROSS THE PACIFIC NORTHWEST ON WEDNESDAY AND THEN REACH
THE ROCKIES BY WEDNESDAY NIGHT. THIS WILL SUPPORT LEE SURFACE
CYCLOGENESIS OVER THE WESTERN HIGH PLAINS BY THURSDAY ALONG AN
EXISTING FRONTAL BOUNDARY. SIMILAR TO THE LEAD SHORTWAVE, THE NAM
APPEARS STRONGER WITH THIS FEATURE CROSSING THE INTERMOUNTAIN WEST
AND THE CMC A LITTLE BROADER WITH THE TROUGH AXIS. THE 12Z GFS IS
A LITTLE QUICKER IN BRINGING MID-LEVEL HEIGHT FALLS TO THE HIGH
PLAINS.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
HAMRICK
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