834
FXUS10 KWNH 100649
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
249 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 FINAL 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. THE 00Z
ECMWF AND ITS MEAN ARE SLIGHTLY TO THE NORTH OF THE MODEL
CONSENSUS AND DOES NOT HAVE THE SYSTEM MAKING AS LARGE OF A LOOP
BEFORE PULLING AWAY FROM THE COAST. THEREFORE A GENERAL MODEL
BLEND WORKS WELL THROUGH 48 HOURS, AND THEN A NAM/EC MEAN/UKMET/
BLEND AFTER THAT.
..CENTRAL U.S. MID-LATITUDE CYCLONE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL 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 ACROSS THE
CENTRAL PLAINS AND MIDWEST AND THEN BECOMES STRONGER WITH THE
SURFACE LOW NEAR THE CANADIAN BORDER, BUT CLOSE ENOUGH TO BE
INCORPORATED INTO THE FORECAST. THE 00Z UKMET HAS COME INTO
BETTER TIMING AGREEMENT WITH THE COLD FRONTAL PASSAGE ACROSS THE
GREAT LAKES AND OHIO VALLEY COMPARED TO ITS 12Z RUN.
..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 12Z
EC MEAN IS NOW AMONG THE STRONGEST WITH THIS OVERALL TROUGH GIVEN
A TREND TO SLIGHTLY LESS AMPLIFIED SOLUTIONS DURING THE 00Z MODEL
RUN CYCLE.
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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