534
FXUS10 KWNH 190431
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1231 AM EDT FRI JUN 19 2020
VALID JUN 19/0000 UTC THRU JUN 22/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
EASTERN U.S. CLOSED LOW AND COASTAL FRONT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND DAY 1; LESS GFS BLEND FOR DAY 2/3
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
AN UPPER LEVEL LOW WILL REMAIN SPREAD OUT OVER THE CENTRAL
APPALACHIANS, MID-ATLANTIC, AND NORTHEAST THROUGH THIS WEEKEND
BEFORE GRADUALLY LIFTING NORTHEAST OFF THE EAST COAST.
SYNOPTICALLY, THE LATEST GUIDANCE SHOWS ABOVE AVERAGE AGREEMENT
AND CONSISTENCY FROM RUN TO RUN. THE MAIN DIFFERENCES LIE ON DAY 3
WHERE THE 00Z NAM SHOWS A MUCH SLOWER EXIT OF THE COAST COMPARED
TO THE GFS (WHICH IS A BIT FASTER THAN THE CONSENSUS) WHILE THE
ECMWF LIES IN BETWEEN. AT THE SURFACE, SOME MODELS HINT AT A LOW
DEVELOPING OFF THE NC COAST IN THE DAY 2/3 PERIOD, THOUGH THE GFS
LACKS THIS FEATURE IN ITS DETERMINISTIC RUN AND MANY OF THE 18Z
GEFS MEMBERS DO NOT SHOW A FEATURE AS WELL. MEANWHILE, THE ECMWF
AND TO SOME DEGREE THE NAM/UKMET/CMC, OFFER A STRONGER LOW WITH
MANY MORE ECENS MEMBERS DEVELOPING IT AFTER 60 HOURS. FROM A
SENSIBLE WEATHER IMPACT, ONLY THE UKMET BRINGS MUCH HIGHER QPF TO
EASTERN NC WITH THE OTHER MODELS WELL OFFSHORE. SO, A GENERAL
MODEL BLEND IS PREFERRED FOR DAY 1 BUT THEN LESS WEIGHT IS
PREFERRED TOWARD THE GFS FOR DAY 2/3.
CLOSED LOW DEVELOPING OVER NORTHERN HIGH PLAINS AND PARADE OF
SHORTWAVES ACROSS CENTRAL PLAINS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-GFS BLEND
CONFIDENCE: AVERAGE
A LARGE UPPER LOW OVER SASKATCHEWAN AND MANITOBA THAT WILL DEVELOP
THROUGH THIS WEEKEND IS WELL AGREED UPON BY THE LATEST MODEL
GUIDANCE. HOWEVER, INDIVIDUAL SHORTWAVES THAT WILL PARADE THE
SOUTHERN PERIPHERY ACROSS THE CENTRAL PLAINS. THE FIRST SHORTWAVE
COMES THROUGH LATE FRIDAY NIGHT INTO SATURDAY, WHERE THE GFS HAS
BEEN CONSISTENTLY A BIT TOO DEEP/STRONG OVER KANSAS/MISSOURI AND
THEN CONTINUES TO BE MORE AMPLIFIED AS IT LIFTS INTO THE UPPER
MISSISSIPPI VALLEY. AS SUCH, ITS LOW TRACK IS TO THE WEST OF THE
MODEL CONSENSUS,A BIT SLOWER, AND STRONGER. FOR D3, ANOTHER
SHORTWAVE COMES OUT INTO THE CENTRAL PLAINS AND HERE THERE ARE
MORE TIMING AND STRENGTH ISSUES. FOR NOW, THE PREFERENCE REMAINS
TO EXCLUDE THE GFS AT THIS TIME AND LEAN TOWARD A ECMWF/UKMET/CMC
BLEND.
TROUGHS APPROACHING THE PACIFIC NORTHWEST THROUGH SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
MULTIPLE SHORTWAVES ROTATING THROUGH THE BROAD GULF OF ALASKA GYRE
WILL FUNNEL AN ACTIVE WEATHER PATTERN ACROSS THE REGION THROUGH
THE WEEKEND. THE FIRST SHORTWAVE REACHES TH B.C. COAST LATE FRIDAY
NIGHT. ASIDE FROM A SLIGHTLY FAST GFS SOLUTION STARTING LATE IN
THE DAY 1 PERIOD AND CONTINUING THROUGH DAY 3, THE MODELS ARE IN
AVERAGE TO ABOVE AVERAGE AGREEMENT SUCH THAT A GENERAL MODEL BLEND
IS SUFFICIENT.
TAYLOR
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page