362
FXUS10 KWNH 250450
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1149 PM EST SUN NOV 24 2019
VALID NOV 25/0000 UTC THRU NOV 28/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...SHORTWAVE ALONG NORTHERN TIER WITH ASSOCIATED AREA OF LOW
PRESSURE MON-TUE...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
CURRENT GOES WV IMAGERY SHOWS SHORTWAVE ENERGY DROPPING INTO THE
NORTHERN U.S. ROCKIES LATE THIS EVENING. THE LATEST MODEL GUIDANCE
CONTINUES TO TIGHTEN WITH THE EVOLUTION OVER THE NEXT 2-3 DAYS AS
THIS WAVE SKIRTS THE U.S. BORDER. AN AREA OF LOW PRESSURE IS
FORECAST TO RACE ACROSS NORTHERN MN AND ACROSS LAKE SUPERIOR
MONDAY BEFORE SHEARING OUT INTO QUEBEC. MODEL GUIDANCE AGREEMENT
IS HIGH ENOUGH ACROSS THE BOARD THAT A GENERAL MODEL BLEND IS
REASONABLE WITH ABOVE AVERAGE FORECAST CONFIDENCE.
...LEAD SHORTWAVE IN DEVELOPING GLOBAL-SCALE TROF IN FOUR CORNERS
BY 00Z TUESDAY...
...DEVELOPMENT OF STRONG/BROAD SURFACE LOW IN PLAINS TUESDAY AND
GREAT LAKES BY WED...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND
CONFIDENCE: AVERAGE
PATTERN CHANGING SHORTWAVE/JET SPEED MAX OVER-TOPPING THE CENTRAL
PACIFIC RIDGE IS EXPECTED TO DIVE SOUTHEAST INTO THE GREAT BASIN
BY 25.18Z. IN THE WEAK, BROAD CYCLONIC FLOW, THIS WAVE STARTS TO
BUCKLE THROUGH THE CENTRAL ROCKIES AND START TO SPIN UP A BROAD
SURFACE CYCLONE ACROSS THE CENTRAL HIGH PLAINS MONDAY INTO
TUESDAY. OVERALL IN THE LAST COUPLE OF MODEL CYCLES, MOST OF THE
DETERMINISTIC GUIDANCE HAS COME INTO BETTER AGREEMENT WITH OVERALL
LESS SPREAD SEEN FOR THE DAY 2/3 FORECAST. THE INITIAL EXCEPTION
IS THE 12Z CMC WHICH IS CONSIDERABLY SLOWER (AND WEAKER) WITH THE
TROUGH AXIS MOVING THROUGH THE CENTRAL PLAINS TUESDAY/TUESDAY
NIGHT AND ITS ASSOCIATED SURFACE LOW TOO FAR TO THE SOUTH AT IT
REACHES THE UPPER MIDWEST. OTHERWISE, THERE IS FAIRLY GOOD
AGREEMENT WITH THE ECMWF/GFS AND THEIR RESPECTIVE ENSEMBLE MEANS.
THE UKMET IS USABLE, BUT HAS SOME OF A SOUTHWARD BIAS COMPARED TO
THE ECMWF/GFS/NAM. OVERALL, GIVEN THE INCREASED CONFIDENCE, WILL
LEAN ON A NON-CMC BLEND FOR THIS CYCLE.
...STRONG SECONDARY SHORTWAVE SUPPORTING WITH VERY DEEP SURFACE
LOW NEAR N CA TUES, EXPANDING
ACROSS NORTHERN CA/N GREAT BASIN BY 00Z THURS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
A STRONGER, SECONDARY CLOSED LOW APPROACHES THE NORTHERN CA /
SOUTHERN OR COAST TUES-WED AND THEN SLOWS/STALLS, BECOMING A
LARGE, WELL-DEVELOPED TROUGH OVER THE WESTERN U.S. BY LATE IN THE
WEEK. A COMPACT, STRONG LOW PRESSURE WILL PUSH INTO THE COAST WITH
FAIRLY GOOD CONSENSUS OF A SUB-980 LOW REACHING THE COAST. IN THE
LAST 24 HOURS, THE MODEL GUIDANCE HAS TIGHTENED CONSIDERABLY, WITH
A SLIGHT NORTHWARD JOG WITH THE OVERALL TRACK OF THE SYSTEM. THERE
IS NOW FAIRLY GOOD CLUSTERING WITH THE MOST RECENT DETERMINISTIC
GUIDANCE AND IN THE LATEST ENSEMBLE GUIDANCE.
AFTER LANDFALL, THE UPPER LOW, BROADENS AND SLIDES SOUTH. THE
GREATEST AGREEMENT EXISTS WITH THE 00Z GFS/12Z ECMWF BUT THE 00Z
NAM AND 12Z UKMET ARE SOLID ENOUGH IN THE ENSEMBLE SUITE TO HAVE
GOOD AGREEMENT TO INCORPORATE INTO A PREFERRED BLEND. WHILE THERE
IS GOOD ALIGNMENT OF THE WAVE DEVELOPMENT TO PROVIDE CONFIDENCE,
ITS CURRENT LOCATION/SOURCE AND INFLUENCES OF THE RIDGE AND
NORTHERN STREAM STILL PROVIDE SOME REDUCED ABSOLUTE CERTAINTY TO
THIS BLEND. SO, WHILE THE CONFIDENCE HAS IMPROVED SUBSTANTIALLY
SINCE YESTERDAY, IT IS STILL AVERAGE. A BLEND OF THE AVAILABLE
DETERMINISTIC GUIDANCE IS PREFERRED 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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