534
FXUS10 KWNH 100437
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1236 AM EDT THU OCT 10 2019
VALID OCT 10/0000 UTC THRU OCT 13/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z INITIAL MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..NORTHEAST STATES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL BLEND THROUGH 00Z SATURDAY, THEN
NAM/ECMWF/UKMET
CONFIDENCE: NEAR AVERAGE
A NOR'EASTER SITUATED JUST EAST OF THE 40N/70W BENCHMARK HAS
GENERALLY LEVELED OFF IN INTENSITY AND IS FORECAST TO MAKE A SLOW
COUNTER-CLOCKWISE LOOP OVER THE NEXT COUPLE OF DAYS BEFORE
TRACKING FARTHER OUT TO SEA. THIS STORM IS BLOCKED BY A LARGE
SURFACE TO MID-LEVEL HIGH OVER EASTERN CANADA AND PART OF A REX
BLOCK PATTERN. THE 12Z ECMWF AND ITS ENSEMBLE MEAN ARE SLIGHTLY
STRONGER WITH THE LOW COMPARED TO THE GFS AND ITS ENSEMBLE MEAN.
THE 00Z GFS IS IN GOOD AGREEMENT THROUGH ABOUT FRIDAY EVENING,
AFTER WHICH IT TRACKS FARTHER TO THE SOUTH DURING ITS CYCLONIC
LOOP NEAR 70W, AND THIS CONTINUES GOING THROUGH SATURDAY.
THEREFORE A GENERAL MODEL BLEND WORKS WELL THROUGH 48 HOURS, AND
THEN A NAM/ECMWF/UKMET BLEND AFTER THAT.
..CENTRAL U.S. MID-LATITUDE CYCLONE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND THROUGH 00Z SATURDAY, THEN
ECMWF/NAM/EC MEAN BLEND
CONFIDENCE: ABOVE AVERAGE
AN IMPRESSIVE UPPER LEVEL TROUGH AND CLOSED LOW OVER THE
NORTH-CENTRAL U.S. IS SPAWNING CYCLOGENESIS OVER THE WESTERN HIGH
PLAINS AND WILL SUPPORT A RAPIDLY DEVELOPING SURFACE LOW THAT WILL
TRACK FROM KANSAS TO NORTHERN MINNESOTA BY EARLY SATURDAY. THIS
WILL BE ACCOMPANIED BY A PRONOUNCED COLD FRONT AND PRECIPITOUS
DROP IN TEMPERATURES ACROSS MUCH OF THE PLAINS, ALONG WITH
POTENTIALLY RECORD SNOWFALL FOR PARTS OF THE DAKOTAS AND
NORTHWESTERN MINNESOTA. THE MODELS REMAIN IN VERY GOOD AGREEMENT
WITH THIS LARGE SCALE STORM SYSTEM THROUGH THE FORECAST PERIOD.
THE GFS DOES BECOME SLIGHTLY MORE AMPLIFIED BY FRIDAY NIGHT ACROSS
THE MIDWEST AND THEN BECOMES STRONGER WITH THE SURFACE LOW NEAR
THE CANADIAN BORDER. THE UKMET IS A LITTLE SLOWER WITH THE
PASSAGE OF THE COLD FRONT ACROSS THE OHIO VALLEY LATE FRIDAY AND
INTO EARLY SATURDAY COMPARED TO THE MULTI-MODEL CONSENSUS.
..WEST COAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF ECMWF/EC MEAN/CMC
CONFIDENCE: AVERAGE
A COMPLICATED MERGER OF TWO STREAMS WEST OF 130W EVENTUALLY LEADS
TO A MORE CONSOLIDATED OPEN TROUGH APPROACHING THE WEST COAST BY
SATURDAY NIGHT INTO SUNDAY. THE NAM BECOMES MORE PROGRESSIVE WITH
THE TROUGH AXIS OVER THE PACIFIC NORTHWEST BY SATURDAY NIGHT AND
STRONGER WITH THE SOUTHERN PORTION OFF THE COAST OF CALIFORNIA,
AND THE UKMET IS WEAKER COMPARED TO THE MODEL CONSENSUS. THE EC
MEAN CONTINUES TO REPRESENT THIS FEATURE WELL AND HAS GOOD SUPPORT
FROM THE ECMWF AND ALSO THE CMC, SO THE PREFERENCE WILL LEAN IN
THIS DIRECTION FOR NOW.
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML
HAMRICK
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