785
FXUS10 KWNH 051835
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
235 PM EDT FRI JUN 05 2020
VALID JUN 05/1200 UTC THRU JUN 09/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
---AMPLIFYING WAVE SHIFTING EAST ACROSS ONTARIO THROUGH TONIGHT
AND NORTHERN NEW ENGLAND SATURDAY NIGHT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL BLEND BECOMING NON-CMC BLEND AFTER 48HRS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
19Z UPDATE: THE CMC IS A BIT SLOWER, BROADER AND FURTHER WEST
ENOUGH TO SUGGEST ITS REMOVAL AFTER 48HRS...7.12Z. CONFIDENCE
REMAINS SLIGHTLY ABOVE AVERAGE
---PRIOR DISCUSSION---
WV SUITE DENOTES A STRONG JET STREAK OVER THE NORTHERN PLAINS INTO
THE WESTERN GREAT LAKES, WITH AN W-E ELONGATED SHORTWAVE ROTOR TO
ITS NORTH. THIS WAVE ALONG WITH THE JET SUPPORT BUCKLES AND
AMPLIFIES THROUGH THE GREAT LAKES, ONTARIO LATER TODAY LEADING TO
A SOLID POSITIVELY TILTED TROF TO PROGRESS THROUGH THE NORTHEAST
LATE SAT AND DIGGING THROUGH THE MID-ATLANTIC BY EARLY SUNDAY.
MODELS CONTINUE TO COME INTO TIGHTER OVERALL AGREEMENT AND WHILE
THERE REMAINS A SMALL AMOUNT OF SPREAD/DIFFERENCE (GFS/CMC) IN THE
MASS FIELDS, A GENERAL MODEL BLEND CAN BE PREFERRED AT SLIGHTLY
ABOVE AVERAGE AGREEMENT.
...INITIAL CUT-OFF LOW OFFSHORE SOUTHERN CALIFORNIA, MOVING
ONSHORE TONIGHT, INTO GREAT BASIN SATURDAY, THE WYOMING ROCKIES
SATURDAY NIGHT, AND THE NORTHERN PLAINS SUNDAY.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
19Z UPDATE: THERE WAS LITTLE SIGNIFICANT CHANGE IN THE 12Z
ECMWF/GEFS/CMC OR UKMET TO DEVIATE FROM INITIAL PREFERENCE,
PERHAPS PROVIDING INCREASED CONFIDENCE OVERALL. SO WILL CONTINUE
WITH A GENERAL MODEL BLEND AT SLIGHTLY ABOVE AVERAGE CONFIDENCE.
---PRIOR DISCUSSION---
GOES-WEST WV SUITE DENOTES A DRY CLOSED LOW WITH EXCELLENT
JET/DOWNSTREAM DIFFLUENCE ACROSS THE DESERT SOUTHWEST. CONVECTIVE
DEVELOPMENT ACROSS THE HIGH TERRAIN LATER TONIGHT INTO TOMORROW
MORNING LEADS TO SOME MILD DISRUPTION OF THE WAVE AS A WHOLE
(EXPANDING IT DOWNSTREAM). THE 12Z NAM IS MOST DISRUPTED AND
STARTS TO ACCELERATE INTO THE NORTHERN HIGH PLAINS MUCH FASTER
THAN OTHER GUIDANCE; ONCE THERE, THE APPROACHING CLOSED LOW (SEE
SECTION BELOW) INTERACTS AND FURTHER AMPLIFIES THE WAVE MAKING THE
NAM SOLUTION A BIT LESS TOLERABLE IN THE OVERALL SUITE,
PARTICULARLY WITH UPPER LEVEL SUPPORT/FEATURES. THE 12Z GFS IS
ALSO A BIT FAST AND MORE AMPLIFIED, PARTICULARLY AS THE UPSTREAM
CLOSED LOW APPROACHES. THE 00Z CMC IS THE OTHER SIDE OF THE
SPECTRUM, SLOWER, ACCOMPANIED BY THE ECMWF. STILL, THE
SPREAD/TIMING IS SMALL ENOUGH TO CONTINUE TO FAVOR A MORE
CENTRALIZED SOLUTION (CLOSE TO THE PLACEMENT/TIMING OF THE
ENSEMBLE SUITE)...AND SO A GENERAL MODEL BLEND IS PREFERRED AT
SLIGHTLY ABOVE AVERAGE CONFIDENCE.
...CLOSED LOW OFF BRITISH COLUMBIA DRIFTING SOUTH THROUGH FRIDAY
NIGHT AND THEN OFF WASHINGTON/OREGON SATURDAY, MOVING EAST AND
ONSHORE SATURDAY NIGHT-SUNDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
19Z UPDATE: FURTHER SEPARATION OCCURRING IN TIMING WITH THE
UKMET/ECMWF/CMC TRENDING CLOSER TOWARD CONSENSUS WHILE THE GFS/NAM
ARE MORE AGREEABLE, WITH THE BULK OF MODAL DIFFERENCES OCCURRING
WITH THE INTERACTION/AMPLIFICATION OF THE PRECURSORY WAVE ACROSS
SOUTHERN CANADA BLEEDING INTO MT. STILL, THE AFFECTS IN THE LOWER
LEVELS/SURFACE A STILL SMALL ENOUGH TO SUPPORT THE GENERAL MODEL
BLEND BUT CONFIDENCE IS REDUCED TO SLIGHTLY ABOVE AVERAGE.
---PRIOR DISCUSSION---
WELL DEFINED SYMMETRIC CLOSED LOW IN THE SOUTHERN GULF OF AK IS
WELL FORECAST THROUGH THE SHORT-TERM AS IT MAKES LANDFALL INTO THE
PACIFIC NORTHWEST THROUGH THE WEEKEND. THE UNCERTAINTY ARISES AS
THE CENTRAL CORE ENHANCED BY THE PACIFIC JET ROUNDS THE BROADENING
BASE INTO THE SNAKE RIVER VALLEY/GREAT BASIN AND BEGINS TO
INTERACT WITH THE EXITING SHORTWAVE LIFTING THROUGH THE NORTHERN
PLAINS. STILL, MOST OF THE UNCERTAINTY COMES WITH DIFFERENCES IN
TIMING WITHIN THE GUIDANCE SUITE AND THEREFORE THE MAGNITUDE OF
AMPLIFICATION WITH THE PRECURSORY WAVE MOVING INTO SW CANADA. THE
GFS IS MOST AGGRESSIVE AND SWINGS THE JET THROUGH WY INTO MT
STRONGER AND FASTER. IT IS SUPPORTED BY THE 12Z NAM BUT BOTH HAVE
SHOWN THIS TO BE A BIT TOO FAST. THE ECMWF/CMC ARE EQUALLY
PROBLEMATIC BUT ON THEIR TYPICAL SLOWER TREND SIDE; WHILE THE
UKMET IS MOST CENTRAL. ALL IN ALL, A BLEND OF THE SOLUTIONS OR A
HEDGE TOWARD THE CENTRAL UKMET IS PREFERRED BUT CONFIDENCE
REMAINS ABOVE AVERAGE IN THIS GENERAL MODEL BLEND PREFERENCE.
..CRISTOBAL
~~~~~~~~~~~~~~~~~~
PREFERENCE: 03Z NHC ADVISORY
BEST PROXY: 12Z UKMET/ECMWF BLEND
CONFIDENCE: REFER TO NHC PRODUCTS
19Z UPDATE: THE ECMWF SHIFTED A BIT FASTER AND STRONGER AND WHILE
INITIALLY A BIT SLOWER THAN THE OFFICIAL FORECAST, IT MATCHES VERY
WELL NEARING THE LA COAST AND THEREAFTER TO SUGGEST A BEST PROXY
IS A COMBINATION OF THE 12Z UKMET/ECMWF BLEND.
---PRIOR DISCUSSION---
THE OFFICIAL TRACK FOR T.D. CRISTOBAL IS A GOOD OF COMPROMISE OF
NON-GFS 00Z GLOBAL GUIDANCE WITH BEST TIMING LOOKING MOST LIKE THE
00Z UKMET. THE 12Z GFS CONTINUES TO BE WELL NORTH AND EAST OF
THE REMAINING GLOBAL GUIDANCE WITH THE BULK OF GEFS SOLUTIONS
THOUGH EVEN THEY ARE SLOWER THAN THE OPERATIONAL. BY THE END OF
DAY 2, THE 12Z NAM IS SHIFTING A BIT WEST OF THE REMAINING CLUSTER
AND THE 00Z CMC IS REMARKABLY WEAK AND DIFFUSE (PARTICULARLY IN
THE MID TO UPPER LEVELS RELATIVE TO THE REMAINING GUIDANCE AND
EVEN THE OUTLYING GFS/NAM AS IT LIFTS NORTH.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
GALLINA
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