608
FXUS10 KWNH 140629
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
128 AM EST TUE JAN 14 2020
VALID JAN 14/0000 UTC THRU JAN 17/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..LARGE SCALE PATTERN ACROSS THE CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z GFS/ECMWF BLEND
NOTE: CMC OK FOR MASS FIELDS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
07Z UPDATE: THE 00Z UKMET TRENDED EVEN FASTER ACROSS THE GREAT
LAKES, AND WHILE IT DID SHIFT A BIT NORTH, IT CONTINUES TO BE A
STRONGER/SOUTH OUTLIER TO THE SUITE. ADDITIONALLY, TYPICAL KNOWN
NEGATIVE BIAS MANIFESTS ALONG THE S CA COAST AT THE END OF D3.
THIS MATCHES (A TAD STRONGER) THAN THE 00Z NAM AND WHILE IT
TRACKS, TIMING-WISE WELL WITH THE OTHER GUIDANCE, THIS STRONGER
SOLUTION IS A TAD TOO AGGRESSIVE FOR DAY 3 WITH THE TWO MOST
AGGRESSIVE MODELS. THE 12Z ECMWF TRENDED A BIT SLOWER ACROSS THE
PACIFIC NORTHWEST TRENDING TOWARD THE GFS/NAM AND CMC WITH THIS
SYSTEM PROVIDING ADDITIONAL GROWING CONFIDENCE WITH THE CLOSED
LOW; UNLIKE THE UKMET/NAM IT IS MORE SENSIBLE ACROSS THE BASE OF
THE TROF CROSSING S CA AND SO A GFS/CMC/ECMWF BLEND IS SUPPORTED
THERE.
IN THE NORTHEAST, THE CMC IS A BIT FURTHER SOUTH, BUT DID PICK UP
PACE TO THE OVERALL SUITE. STILL WILL FAVOR A GFS/ECMWF BLEND FOR
THIS SYSTEM, THE CMC AND NAM STILL SEEM TO HAVE SOME WEAK SUPPORT
AND REMAIN VIABLE WITHIN A BLEND IF DESIRED TO ACCOUNT FOR THE
MILD UNCERTAINTY.
---PRIOR DISCUSSION---
A LARGE SCALE CONSENSUS STARTED LAST EVENING IN HANDLING THE
REMAINS OF THE ARCTIC VORTEX HUB ACROSS BC/ALBERTA, AND NOW THE
LAST STRAGGLERS HAVE COME INTO LINE WITH THE ECMWF/ECENS SOLUTIONS
WRAPPING THE ENERGY BACK WEST INTO THE DEVELOPING CLOSED LOW/BROAD
CYCLONE NEAR VANCOUVER ISLAND. THE ENERGY THAT DOES SHEAR
DOWNSTREAM IN THE WAKE OF THE LAST FAST MOVING PACIFIC SHORTWAVE
THAT IS CURRENTLY ENTERING THE PACIFIC NORTHWEST (AND REMAINS IN
SOLID MODEL AGREEMENT THROUGH ITS TREK THROUGH THE NORTHERN PLAINS
INTO THE GREAT LAKES WED/THURSDAY) LEADS TO EVOLUTIONARY
DIFFERENCES IN TIMING/LATITUDE FOR THE SYSTEM ACROSS THE LOWER
GREAT LAKES INTO THE NORTHEAST BY THURSDAY. HERE, THE 00Z NAM
HAS TRENDED MORE FAVORABLY, YET STILL IS QUITE STRONG WITH BOTH
THE LEADING SHORTWAVE AS WELL AS THE SHEARED ENERGY ACROSS THE
GREAT LAKES, SUPPORTING VERY DEEP COASTAL LOW DEVELOPMENT AND
GREATER OVERALL AMPLITUDE OF THE WAVE BY 00Z FRI AND IS WITHIN THE
REALM/BULK OF ENSEMBLE SOLUTIONS IF JUST A TAD TOO DEEP. THE 12Z
UKMET IS A BIT TOO FAST WITH THE PACIFIC STREAM WAVE AND THEREFORE
EVOLVES A BIT FURTHER SOUTH ACROSS NEW ENGLAND INTO COASTAL WATERS
TO BE SUPPORTED HERE. THE 12Z CMC IS GENERALLY SLOW ABOUT 3-6HRS
RELATIVE TO THE ECMWF/GFS BUT AT LEAST SHOWS A VERY SIMILAR
EVOLUTION/INTERACTION THROUGH THE DEPTH OF THE DEVELOPING WAVE TO
KEEP AT LOWER WEIGHTING IN THE PREFERENCE. OTHERWISE, AN
ECMWF/GFS BLEND IS SUPPORTED AT SLIGHTLY ABOVE AVERAGE CONFIDENCE
(WITH SOME INCLUSION OF THE CMC/NAM TO ACCOUNT FOR SOME LOWER
PROBABILITIES).
AS FOR THE WEST DEVELOPING/DEEP CLOSED LOW AND HIGH AMPLITUDE TROF
BY WED/THURS. THE ECMWF CONTINUES TO BE VERY STRONG BUT VERY
UNCHARACTERISTICALLY FAST TO DEEPEN/OCCLUDE. WHILE, THIS HAS BEEN
A VERY CONSISTENT SIGNAL IT IS A BIT CONCERNING GIVEN THE GFS IS
EQUALLY SLOW, ALMOST IF THEY SWAPPED TRADITIONAL MODEL DIFFERENCES
(ROLES). THE UKMET IS MORE LIKE THE ECMWF AND THE CMC/NAM ARE
MORE GFS LIKE. THE LARGER DIFFERENCE MANIFEST IN THE SHORTWAVE
THAT CARVES OUT THE BASE OF THE HIGH-AMPLITUDE TROF ENTERING THE
CA COAST LATE THURSDAY. HERE THE NAM LOOKS TO HAVE TYPICAL END OF
CYCLE, OVER-AMPLIFICATION NEGATIVE BIAS. SO GENERALLY, AN
ECMWF/GFS BLEND WITH LOWER WEIGHT INCLUSION OF THE UKMET/CMC IS
PREFERRED AT SLIGHTLY ABOVE AVERAGE CONFIDENCE AS WELL.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
GALLINA
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