038
FXUS10 KWNH 080625
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
225 AM EDT WED APR 08 2020
VALID APR 08/0000 UTC THRU APR 11/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCE AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...SURFACE WAVE MOVING THROUGH THE GREAT LAKES TONIGHT, THEN
SLIDING OFFSHORE ALONG 40N WED/THURS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
07Z UPDATE: THE 00Z UKMET, CMC AND ECMWF ALL SHIFTED SLIGHTLY
FASTER TO FURTHER TIGHTEN THE SPREAD; ENOUGH TO SUPPORT A GENERAL
MODEL BLEND AT ABOVE AVERAGE CONFIDENCE.
---PRIOR DISCUSSION---
THE 00Z GFS DID SLOW AND SLIDE SOUTH WITH THE DEVELOPING OFFSHORE
SURFACE LOW, BRINGING IT CLOSER TO THE OVERALL SUITE. WHILE THE
12Z ECMWF/CMC AND LASTLY UKMET ARE SLOWER AND THEREFORE AND MORE
SOUTH OF 40N; THE CLOSENESS AND TIGHTENING OF SOLUTIONS SUPPORTS A
GENERAL MODEL BLEND AT SLIGHTLY ABOVE AVERAGE CONFIDENCE.
...UPPER TROUGH DIGGING ACROSS GREAT LAKES; STRONG SURFACE LOW
DEVELOPING OFF NEW ENGLAND COAST THURSDAY NIGHT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE TO ABOVE AVERAGE
07Z UPDATE: FRONTAL TIMING AND STRENGTH/PLACEMENT OF TRIPLE POINT
DEVELOPMENT ACROSS THE NORTHEAST CONTINUE TO MATCH SOLIDLY TO
CONTINUE A SUPPORT OF A GENERAL MODEL BLEND (AFTER ASSESSING THE
00Z GEFS/CMC/UKMET AND ECMWF). SMALLER SCALE/MESOSCALE FEATURES
ARE EVEN NOW COMING INTO AGREEMENT, WHICH IS IMPRESSIVE THIS FAR
OUT. STILL, THERE REMAINS SOME IMPORTANT LATITUDINAL/DEPTH
DIFFERENCES TO NOT HAVE FULL CONFIDENCE IN A GENERAL MODEL BLEND
BUT IT IS VERY CLOSE.
---PRIOR DISCUSSION---
THE OVERALL MODEL SUITE CONTINUES TO TIGHTEN OVERALL. THE 00Z
NAM/GFS THOUGH ARE A TAD WEAKER BECOMING ELONGATED MORE THAN THE
CONCENTRIC ECMWF/CMC. STILL, THE MASS FIELDS, TIMING AND LOCATION
OF THE SURFACE LOW(S), INCLUDING THE RAPID DEEPENING THROUGH
SOUTHERN NEW ENGLAND/GULF OF MAINE LOOK ON TRACK TO SUPPORT A
GENERAL MODEL BLEND AT SLIGHTLY ABOVE AVERAGE CONFIDENCE.
...SLOW MOVING SOUTHERN STREAM (S CA/DESERT SOUTHWEST) CLOSED
LOW...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z NAM/ECMWF/CMC/GEFS AND 12Z ECENS MEAN BLEND
CONFIDENCE: AVERAGE
07Z UPDATE: THE 00Z CMC AND GEFS BOTH TRENDED WESTWARD, WHILE THE
ECMWF IS LESS FRACTURED/WEST COMPARED TO THE 12Z ECENS SUITE, SO
CONFIDENCE IS INCREASING TOWARD FURTHER SLOWING DOWN THE LOW, AND
SO WILL INCORPORATE MORE ECMWF AND LESS GFS (REPLACED WITH THE
GEFS). SO A 00Z NAM/ECMWF/CMC BLEND WITH THE 00Z GEFS AND 12Z
ECENS IS PREFERRED AT AVERAGE CONFIDENCE.
---PRIOR DISCUSSION---
THE 00Z NAM AND GFS BOTH SHIFTED SLOWER AND WOBBLED MORE CENTRALLY
THAN SAY THE 12Z UKMET/ECMWF WHICH CONTINUE TO BREAK DOWN THE
INNER CORE OF THE LARGER SCALE AND WOBBLE MUCH FURTHER WEST. THIS
WILL ALSO ALLOW FOR GREATER TAPPING OF THE OFFSHORE MOISTURE
STREAM FOR INCREASED QPF THREAT. WHILE NOT OUT OF THE REALM OF
POSSIBILITY (GIVEN THE LONGER TERM TRENDS OF SLOWING) THE
UKMET/ECMWF REMAIN ON THE FAR WESTERN SIDE OF THE ENSEMBLE SUITE.
THIS WHILE THE 00Z NAM/GFS AND 12Z CMC ARE MORE REPRESENTATIVE OF
THE SUITE AS A WHOLE (INCLUDING THE CMCE AND ECENS MEMBERS). AS
SUCH, WILL SUPPORT A 00Z NAM/GFS AND 12Z CMC BLEND TO REPRESENT
THE GREATER PROBABILITIES AND KNOWING THE NEGATIVE BIASES OF THE
ECMWF/UKMET...WHICH SEEM TO BE MANIFESTING WITH EACH RUN.
CONFIDENCE REMAINS AVERAGE.
...UPPER TROUGH AND RELATED SURFACE COLD FRONT REACHING MT/ND ON
FRIDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
07Z UPDATE: THE CMC SHIFTED NORTH (STRONGER/SLOWER) AND WHILE IT
IS STILL A TAD SOUTH OF THE GROWING CONSENSUS AND SMALL ADJUSTMENT
FASTER/EAST/SOUTH OF THE UKMET/ECMWF HELPS TO ENCOMPASS THE CMC IN
THE OVERALL SPREAD WELL, TO SUPPORT A GENERAL MODEL BLEND AT
SLIGHTLY ABOVE AVERAGE CONFIDENCE.
---PRIOR DISCUSSION---
SHORTWAVE ALONG THE SOUTH COAST OF AK WILL PROGRESS EASTWARD INTO
THE YUKON TERRITORY AND WITH THE ACCELERATING/EXITING JET, THE
UPSTREAM RIDGE WILL BREAK DOWN AND ALLOW FOR GREATER PROPAGATION
EAST AND THEN SOUTHWARD ACROSS CENTRAL CANADA. THE HEIGHT-FALLS
WILL OVER SPREAD THE LEE OF THE CANADIAN ROCKIES INTO THE US
NORTHERN HIGH PLAINS AND SUPPORT A COLD FRONT TO DROP SOUTHWARD.
THE GUIDANCE IS REMARKABLY TIGHT WITH THE EXCEPTION OF THE 00Z CMC
WHICH IS UNCHARACTERISTICALLY FAST, AND THERE FORE SOUTH WITHIN
THE OVERALL SUITE. THE 00Z NAM/GFS CONTINUED SOLID CONTINUITY AND
AGREEMENT TO KEEP WITH A NON-CMC BLEND AT SLIGHTLY ABOVE AVERAGE
CONFIDENCE.
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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