077
FXUS10 KWNH 020650
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
250 AM EDT FRI AUG 02 2019
VALID AUG 02/0000 UTC THRU AUG 05/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION AND PREFERENCES/CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..CENTRAL U.S
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF GFS/ECMWF
CONFIDENCE: AVERAGE
THE MODELS SHOW THE ENERGY DROPPING DOWN ACROSS SD/NE TONIGHT
THROUGH MIDDAY ON FRIDAY AND THEN ACROSS EASTERN KS FRIDAY NIGHT
AND EARLY SATURDAY. THE 00Z UKMET IS THE WEAKEST OF ALL OF THE
GUIDANCE WITH THE 700 MB ENERGY AS IT DROPS DOWN THE EAST SIDE OF
THE RIDGE AXIS. THE 00Z NAM IS THE MOST INTENSE AND HAS A DEEPER
700 MB LOW THAN THE OTHER MODELS. THIS MAY BE DUE TO
CONVECTIVELY-INDUCED GRID SCALE FEEDBACK.
THE NAM TRACK OF THE 700 MB WAVE IS COMPARABLE TO OTHER GUIDANCE,
BUT NEEDS TO BE WEAKENED.
..NORTHEAST U.S./UPPER OHIO VALLEY/NORTHERN MID ATLANTIC
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
ACROSS THE NORTHEAST DOWN THROUGH THE LOWER LAKES, UPPER OHIO
VALLEY, AND NORTHERN APPALACHIANS,
HEIGHTS GRADUALLY LOWER WITH TIME THIS WEEKEND. THE NAM/GFS AND
SREF/GEFS MEANS CLUSTER WELL ACROSS THE REGION. THE 00Z ECMWF WAS
NOT QUITE AS FLAT AS THE SOLUTION IT OFFERED AT 12Z ON
THURSDAY...BUT IT WAS STILL AN OUTLIER COMPARED TO OTHER
GUIDANCE...AND WAS PREFERRED LESS THAN THE OTHER GUIDANCE BASED ON
TELECONNECTIONS WITH THE SOUTHWEST CLOSED LOW.
..PACIFIC NORTHWEST/SOUTHWEST CANADA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z CMC/UKMET/ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE GUIDANCE AGREES IN TAKING A POSITIVELY TILTED LONGWAVE TROUGH
ACROSS SOUTHWEST BRITISH COLUMBIA, VANCOUVER ISLAND, AND OFF THE
NORTHWEST COAST AND MOVING THE WAVE NORTHEAST INTO CENTRAL CANADA
OVER THE WEEKEND. THE MODELS INDICATE A 700 MB SHEAR AXIS REMAINS
OFF THE WA/OR COAST THAT PERSISTS AND EVENTUALLY DEVELOPS INTO A
SECOND CLOSED LOW SUNDAY. THE 00Z NAM TRENDED WEST TO JOIN THE
PRIMARY CLUSTER OF MODELS, SO NOW CAN BE CONSIDERED PART OF THE
PREFERRED BLEND.
THE LATEST ENSEMBLE MEANS PER THE GEFS MEAN AND ECENS MEAN ARE
SUPPORTIVE OF THE OPERATIONAL MODELS.
THE 21Z SREF MEAN WAS ON THE EASTERN EDGE OF THE SUITE OF
SOLUTIONS AND THEREFORE LEAST PREFERRED, GIVEN THE DOWNSTREAM
BLOCKING HIGH LIMITING FORWARD MOTION.
..UPPER TROUGH OVER THE GULF COAST/SOUTHEAST
..WAVE AXIS IMPACTING FLORIDA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z NAM/UKMET/ECMWF SOLUTIONS
CONFIDENCE: AVERAGE
A BROAD UPPER TROUGH OVER THE GULF COAST STATES WILL GRADUALLY
DRIFT WEST OVER THE WEEKEND.
THE MID LEVEL CIRCULATION AND SURFACE WAVE NEAR SOUTH FLORIDA MOVE
NORTHEAST AHEAD OF THE UPPER TROUGH ACROSS THE SOUTHEAST COAST AND
THEN OFF THE COAST THIS WEEKEND. THE 00Z NAM WAS A LITTLE
STRONGER WITH THE 700 MB LOW AND SEEMS TO MATCH THE CIRCULATION
SEEN ON RADAR AND SATELLITE. THE GFS WAS A TAD MORE AMPLIFIED
THAN THE NON-NCEP GUIDANCE WITH THIS TROUGHING, WITH THE UKMET
DEAMPLIFYING IT FASTER. THE 00Z UKMET AND 12Z CANADIAN WERE LEAST
PREFERRED GIVEN TELECONNECTIONS FAVOR A PERSISTENT HIGHER
AMPLITUDE TROUGH.
REGARDING THE SURFACE TROUGH IMPACTING FLORIDA, THE GUIDANCE IS
GRADUALLY SUPPORTING DEVELOPMENT OF A WEAK LOW CENTER ALONG THIS
AS IT LIFTS NORTHEAST UP OFF THE SOUTHEAST COASTLINE THIS WEEKEND.
THE 00Z NAM BECAME THE STRONGEST SOLUTION AS THE LOW MOVES OFF THE
MID ATLANTIC COAST. GIVEN MOST SOLUTIONS SHEAR THE 700-850 MB
CIRCULATION, A BLEND OF SOLUTIONS SHOULD SUFFICE.
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML
PETERSEN/BANN
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