821
FXUS10 KWNH 020704
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
203 AM EST THU JAN 02 2020
VALID JAN 02/0000 UTC THRU JAN 05/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..UPPER LOW OVER MEXICO SHEARING TO THE NORTHEAST
..FRONTAL WAVE IMPACTING THE GULF COAST/TN VALLEY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE MODELS SHOW GOOD AGREEMENT IN LIFTING THE SOUTHERN STREAM
CLOSED LOW OVER MEXICO OFF TO THE NORTHEAST OVER THE NEXT 24 HOURS
WITH THE SYSTEM SHEARING OUT ACROSS THE LOWER RIO GRANDE VALLEY AS
IT BECOME EMBEDDED IN DEEP LAYER SOUTHWEST FLOW AHEAD OF AN
AMPLIFYING TROUGH OVER THE SOUTHERN HIGH PLAINS. THE GUIDANCE
THOUGH DOES SUPPORT THE IDEA OF A WEAK AREA OF LOW
PRESSURE/FRONTAL WAVE LIFTING NORTHEAST OUT OF THE NORTHWEST GULF
OF MEXICO AND ACROSS MS/AL BEFORE DAMPENING OUT. THIS WILL BE A
PLAYER IN GENERATING HEAVY TO EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE GULF COAST STATES/TN VALLEY. A GENERAL MODEL BLEND WILL BE
PREFERRED.
...AMPLIFYING LONGWAVE TROUGH ACROSS THE CENTRAL U.S.
..SURFACE LOW FROM THE LOWER MS VALLEY TO THE NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z NAM/12Z ECENS MEAN
CONFIDENCE: BELOW AVERAGE
A SPLIT FLOW UPPER TROUGH WITH SEVERAL SMALL SCALE SHORTWAVE
IMPULSES WILL EJECT OUT ACROSS THE PLAINS GOING THROUGH THE END OF
THE WEEK, WITH INITIALLY THE DOMINANT AMPLIFICATION OCCURRING DOWN
OVER THE SOUTHERN HIGH PLAINS. HOWEVER, BY LATE FRIDAY, MULTIPLE
PIECES OF ENERGY IN THE NORTHERN STREAM WILL DIG DOWN ACROSS THE
MIDWEST AND LEAD TO A MORE DOMINANT NORTHERN STREAM TROUGH AND
CLOSED LOW EVOLUTION WHICH WILL LIKELY PICK UP THE SOUTHERN STREAM
ENERGY. THIS WILL LEAD TO SURFACE LOW DEVELOPMENT OVER THE LOWER
MS VALLEY WHICH WILL LIFT NORTHEAST TOWARD THE OH VALLEY BY
SATURDAY. THIS SYSTEM WILL CROSS THE NORTHERN MID-ATLANTIC BY
SATURDAY EVENING WITH LOW PRESSURE REDEVELOPING SOUTH OF LONG
ISLAND BY EARLY SUNDAY. THE 00Z GFS HAD TRENDED CLOSER TO THE 12Z
ECMWF AND GEFS/ECENS MEAN CLUSTER REGARDING THE LOW AND AND
MID-LEVEL TROUGH EVOLUTION. HOWEVER, WITH THE REMAINING 00Z CYCLE
OF GUIDANCE, THE 00Z UKMET AND ESPECIALLY THE 00Z ECMWF/CMC
SOLUTIONS HAVE ALL TRENDED A BIT MORE PROGRESSIVE AND FARTHER
SOUTH. THIS IS RELATED TO THE REMNANT SOUTHERN STREAM ENERGY BEING
A BIT MORE PROGRESSIVE AND NOT COMPLETELY PHASING WITH THE
STRONGER AFOREMENTIONED NORTHERN STREAM CLOSED LOW. THE 00Z GEFS
MEAN IS NOW OUT OF TOLERANCE WITH THE GFS TOWARD THE END OF THE
PERIOD AND SUGGESTS THE GFS IS TUCKING LOW PRESSURE IN TOO CLOSE
TO SOUTHERN NEW ENGLAND AND THEN THE GULF OF MAINE. THE 00Z CMCE
THOUGH SUGGESTS THAT THE CMC/ECMWF DETERMINISTIC SOLUTIONS ARE
PERHAPS OVER ADJUSTING TOO FAR SOUTH. AS A MEANS OF COMPROMISING
IN BETWEEN THE CAMPS, A PREFERENCE TOWARD A BLEND OF THE 00Z
NAM/12Z ECENS MEAN WILL BE RECOMMENDED.
..SHORTWAVE TROUGH/LOW IMPACTING THE PACIFIC NORTHWEST
..ENERGY EJECTING OUT ACROSS THE PLAINS/MIDWEST BY SAT/SUN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
MODEL AGREEMENT IS ACTUALLY RATHER GOOD WITH THE FIRST SHORTWAVE
AND ATTENDANT SURFACE LOW THAT AIMS FOR CENTRAL BRITISH COLUMBIA
BY LATE THURSDAY WHICH WILL HELP DRIVE A WARM FRONT UP ACROSS
WESTERN WA THURSDAY NIGHT. AFTER THIS SYSTEM, FAST UPSTREAM
PACIFIC FLOW WILL DRIVE ANOTHER SHORTWAVE AND STRONG SURFACE LOW
EASTWARD TO NEAR THE NORTHERN END OF VANCOUVER ISLAND BY FRIDAY
NIGHT. A COLD FRONT ASSOCIATED WITH THIS WILL THEN CROSS THE
PACIFIC NORTHWEST BY EARLY SATURDAY. THE 00Z CYCLE OF GUIDANCE HAS
COME INTO BETTER AGREEMENT WITH THE TIMING DETAILS OF THE SECOND
SYSTEM WITH ONLY THE 00Z NAM NOW PERHAPS APPEARING A TAD TOO SLOW.
THIS SYSTEM WILL ADVANCE VERY QUICKLY DOWNSTREAM ACROSS THE
INTERMOUNTAIN WEST AND ACROSS THE NORTHERN PLAINS AND MIDWEST
SATURDAY AND SUNDAY. THE 00Z NAM BY THE END OF THE PERIOD DOES
APPEAR A TAD TOO SLOW AS LOW PRESSURE AND A FRONTAL SYSTEM CROSSES
SOUTHERN CANADA AND ADJACENT AREAS OF THE PLAINS/MIDWEST. GIVEN
THE LATEST TRENDS AND MODEL CLUSTERING, A NON-NAM BLEND WILL BE
PREFERRED WITH THIS ENERGY.
..SPLIT FLOW TROUGH NEAR THE PACIFIC NORTHWEST BY SUN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND
CONFIDENCE: AVERAGE
THE MODELS SHOW A NEW SPLIT FLOW UPPER TROUGH AND ATTENDANT FRONT
APPROACHING THE PACIFIC NORTHWEST BY SUNDAY. THE 00Z NAM/GFS
SOLUTIONS ARE A TAD FASTER THAN THE 00Z UKMET/ECMWF SOLUTIONS, BUT
THERE IS A BIT BETTER CLUSTERING WITH BOTH THE NORTHERN AND
SOUTHERN STREAM COMPONENTS. THE 00Z CMC OVERALL APPEARS A BIT TOO
SLOW WITH THE ENTIRE EVOLUTION OF THE TROUGH AXIS, SO A NON-CMC
BLEND WILL BE PREFERRED.
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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