284
FXUS10 KWNH 130713
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
312 AM EDT FRI SEP 13 2019
VALID SEP 13/0000 UTC THRU SEP 16/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...NORTHERN PLAINS/UPPER MIDWEST CLOSED LOW AND APPROACHING
SHORTWAVE...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
A CLOSED LOW CURRENTLY OVER THE NORTHERN PLAINS WILL LIFT
NORTHEAST AND OPEN UP AS IT MOVES TOWARD ONTARIO/QUEBEC THIS
WEEKEND. THROUGH 36 HOURS, THERE ARE ONLY SUBTLE DIFFERENCES IN
THE 500 MB HEIGHTS AND MASS FIELDS. A SECONDARY SHORTWAVE BEHIND
THE MAIN WAVE THEN APPROACHES THE NORTHERN TIER OF THE U.S. AND
SOUTHERN CANADA. THE 00Z GFS IS A BIT DEEPER/AMPLIFIED COMPARED TO
THE REST OF THE GUIDANCE. OTHERWISE, GUIDANCE IS IN FAIRLY GOOD
AGREEMENT THROUGH THE END OF DAY 3 AND A GENERAL MODEL BLEND IS
PREFERRED.
..CLOSED LOW APPROACHING PACIFIC NORTHWEST DAY 3
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-UKMET BLEND
CONFIDENCE: ABOVE AVERAGE
07Z UPDATE: THE 00Z UKMET REMAINS TOO FAST WITH THE DIGGING TROUGH
OVER THE PACIFIC NORTHWEST, ESPECIALLY BY DAY 3. THE REST OF THE
MODELS KEEP THE TROUGH AXIS OFFSHORE BY THE END OF DAY 3, WHILE
THE UKMET IS SOLIDLY ACROSS THE INTERIOR PORTIONS OF OR/WA. WITH
THIS IN MIND, FELT THAT IT IS TOO FAST AND SHOULD BE EXCLUDED FROM
THE BLEND, ESPECIALLY FOR DAY 2/3.
---PREVIOUS DISCUSSION---
A BROAD AND STRONG CLOSED LOW IS EXPECTED TO DROP SOUTHEAST FROM
THE AK COAST TOWARD THE PACIFIC NORTHWEST BY THE END OF DAY 3.
THERE IS ABOVE AVERAGE SUPPORT FROM THE DETERMINISTIC AND ENSEMBLE
GUIDANCE WITH THE EVOLUTION OF THIS SYSTEM SUCH THAT A GENERAL
MODEL BLEND OF THE AVAILABLE GUIDANCE IS PREFERRED AT THIS TIME.
THE 12Z UKMET IS PERHAPS A TAD FASTER THAN THE REST OF THE
GUIDANCE BUT ITS DIFFERENCES ARE NOT SIGNIFICANT ENOUGH TO BE
EXCLUDED AT THIS TIME.
..POTENTIAL TROPICAL CYCLONE NINE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: OFFICIAL NHC FORECAST
CONFIDENCE: MUCH BELOW AVERAGE
07Z UPDATE: THE REST OF THE 00Z GUIDANCE TRENDED TOWARD THE EAST
SIMILARLY TO THE GFS/NAM, WITH PRETTY MUCH ALL THE GUIDANCE NOW
TAKING THE LOW WELL OFF THE FL/GA COASTLINE BY DAY 3, ALTHOUGH
THERE IS CONSIDERABLE DIFFERENCES IN TERMS OF STRENGTH/INTENSITY.
THIS IS A BELOW AVERAGE FORECAST, PARTICULARLY BEYOND 24-36 HOURS.
THE LATEST OFFICIAL NHC TRACK LIES SIMILAR TO A NAM/CMC/ECMWF
BLEND BUT USERS SHOULD SEE THE OFFICIAL ADVISORY FOR THE LATEST
INFORMATION REGARDING POTENTIAL TROPICAL CYCLONE NINE.
---PREVIOUS DISCUSSION---
SEE THE LATEST OFFICIAL NHC ADVISORY ON POTENTIAL TROPICAL CYCLONE
NINE.
SATELLITE IMAGERY CONTINUES TO SHOW BLOSSOMING CONVECTIVE CLOUD
TOPS AROUND POTENTIAL TROPICAL CYCLONE 9 LOCATED OVER THE
SOUTHEASTERN BAHAMAS. THERE IS A GROWING CONSENSUS IN THE CYCLONE
DEVELOPING INTO A TROPICAL STORM AS IT APPROACHES THE EAST COAST
OF FLORIDA IN THE NEXT COUPLE OF DAYS. THE TRACK HOWEVER REMAINS
UNCERTAIN. THE 00Z GFS DID TREND TOWARD THE OTHER NON-NCEP
GUIDANCE AND SHIFTED EASTWARD, ALTHOUGH IT REMAINS THE WESTERN
OUTLIER WITH ITS SURFACE LOW MOVING TOWARD TAMPA AND THEN TURNING
NORTHEAST TOWARD LAKE CITY. MEANWHILE, THE 12Z UKMET/CMC/ECMWF
ALL REMAINED OFF THE EAST COAST OF FL, ALTHOUGH WITH VARYING
DEGREES OF INTENSITY. A TIME TREND ANALYSIS OVER THE PAST 4 MODEL
CYCLES SHOW THE GEFS MEMBERS TRENDING EASTWARD TOWARD THE ECENS
AND CMCE SOLUTIONS. THE 00Z NAM ALSO OFFERS SOME UTILITY AS ITS
TRACK IS FAIRLY SIMILAR TO THE OFFICIAL. FOR NOW, BASED ON THE
LATEST ADVISORY, THE BEST PROXY IS A CONSENSUS OF THE ECENS/CMCE
WITH SOME INCLUSION OF THE NAM THROUGH DAY 3.
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML
TAYLOR
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