572
FXUS10 KWNH 250640
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
239 AM EDT FRI OCT 25 2019
VALID OCT 25/0000 UTC THRU OCT 28/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..SHORTWAVE TROUGH OVER THE UPPER MIDWEST/GREAT LAKES ON FRI
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
A SHORTWAVE TROUGH CLIPPING THE NORTHERN PLAINS AND UPPER MIDWEST
WILL CROSS THROUGH THE GREAT LAKES ON FRIDAY, BEFORE THEN
ADVANCING EAST OVER THE NORTHEAST BY SATURDAY. THERE IS SOME
MODEST TIMING DIFFERENCES ASSOCIATED WITH THE ENERGY AS IT CROSSES
THE NORTHEAST, BUT A GENERAL MODEL BLEND WILL BE PREFERRED TO
RESOLVE THESE MINOR DIFFERENCES.
..AMPLIFYING TROUGH/CLOSED LOW OVER THE SOUTHERN PLAINS
..ENERGY LIFTING NORTHEAST TOWARD THE OH VALLEY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z CMC/ECMWF AND 12Z ECENS MEAN
CONFIDENCE: AVERAGE
THE MODELS SHOW VERY GOOD AGREEMENT IN TAKING AMPLIFYING
TROUGH/CLOSED LOW OVER THE SOUTHERN HIGH PLAINS OFF TO THE EAST
ACROSS THE BROADER SOUTHERN PLAINS ON FRIDAY, AND THEN
NORTHEASTWARD ACROSS THE LOWER/MIDDLE MS VALLEY ON SATURDAY, AND
FINALLY ACROSS THE OH VALLEY AND LOWER GREAT LAKES REGION ON
SUNDAY. THERE CONTINUES TO BE A BIT OF MODEL SPREAD WITH TIMING OF
THE HEIGHT FALLS AS THEY EJECT OUT OF THE LOWER MS VALLEY.
GRADUALLY THE 00Z NAM AND ESPECIALLY THE 00Z GFS BECOME THE MORE
PROGRESSIVE SOLUTIONS WHICH RESULTS IN A MORE PROGRESSIVE SURFACE
LOW EVOLUTION UP ACROSS THE OH VALLEY AND LOWER GREAT LAKES
THROUGH THE WEEKEND. THE 00Z NON-NCEP MODELS ARE ALL SLOWER, WITH
THE 00Z UKMET AGAIN THE SLOWEST SOLUTION. THE CMC/ECMWF SOLUTIONS
BETTER APPROXIMATE THE MODEL CONSENSUS AND HAVE BETTER ENSEMBLE
SUPPORT VIA THE 00Z GEFS MEAN AND 12Z ECENS MEAN. A PREFERENCE
TOWARD THE CMC/ECMWF AND ECENS MEAN SOLUTIONS WILL BE PREFERRED,
AND THIS WILL APPLY AS WELL TO THE BAROCLINIC LOW FORMATION OVER
THE NORTHWEST GULF OF MEXICO THAT ULTIMATELY LIFTS NORTHEAST
THROUGH THE LOWER MS VALLEY AND TOWARD THE LOWER GREAT LAKES
THROUGH THE WEEKEND.
..LOW PRESSURE LIFTING NORTH OUT OF THE BAY OF CAMPECHE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z CMC/ECMWF AND 12Z ECENS MEAN
CONFIDENCE: AVERAGE
AN AREA OF LOW PRESSURE LIFTING NORTH OUT OF THE BAY OF CAMPECHE
IS FORECAST TO ADVANCE NORTH-NORTHEAST TOWARD AREAS OF
SOUTH-CENTRAL TO SOUTHEAST LA BY LATE FRIDAY NIGHT OR EARLY
SATURDAY MORNING AS THE SYSTEM GETS PICKED UP BY THE LOWER MS
VALLEY TROUGH/CLOSED LOW SYSTEM. THIS LOW SHOULD MERGE WITH THE
ATTENDANT COLD FRONT DIGGING SOUTHEAST ACROSS THE NORTHWEST GULF
OF MEXICO. THE 00Z NAM SUGGESTS THE LOW CENTER GETS LEFT BEHIND
OVER THE CENTRAL GULF OF MEXICO ON SUNDAY, BEFORE THEN ADVANCING
NORTHEAST TOWARD THE FL PANHANDLE BY EARLY MONDAY. THE 00Z GFS
SUGGESTS THE SYSTEM WEAKENS AND DISSIPATES OVER THE CENTRAL GULF
OF MEXICO. HOWEVER, THE 12Z NON-NCEP GUIDANCE, ALONG WITH THE 12Z
ECENS MEAN AND 00Z GEFS MEAN ALL STRONGLY SUPPORT A LOW CENTER
THAT MAINTAINS SUFFICIENT DEFINITION TO COME NORTH AND ADVANCE
INLAND ACROSS SOUTH-CENTRAL OR SOUTHEAST LA BEFORE THEN ELONGATING
AND DISSIPATING ALONG THE AFOREMENTIONED FRONT AS IT MOVES UP
ACROSS SOUTHERN MS AND PORTIONS OF AL. THE NAM AND GFS SOLUTIONS
WILL BE DISMISSED FOR THE TIME BEING CONSIDERING THE CURRENT LEVEL
OF ORGANIZATION SEEN WITH THE SYSTEM IN THE LATEST SATELLITE
IMAGERY ALONG WITH ITS CURRENT NORTHWARD HEADING. THE CMC/ECMWF
AND ECENS MEAN OVERALL REFLECT GOOD MODEL CLUSTERING AND A BLEND
OF THESE SOLUTIONS WILL BE PREFERRED.
..UPPER TROUGH DIGGING ACROSS THE INTERMOUNTAIN WEST BY SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z ECMWF/GEFS MEAN AND 12Z ECENS MEAN
CONFIDENCE: ABOVE AVERAGE
A STRONG DEEP LAYER RIDGE IS FORECAST TO EVOLVE OVER THE GULF OF
AK THIS WEEKEND WHICH WILL ALLOW SHORTWAVE ENERGY TO DIG SOUTH
ACROSS SOUTHWEST CANADA AND THEN INTO INTERMOUNTAIN WEST AND
NORTHERN PLAINS BY SUNDAY. SOME STREAM SEPARATION IS EXPECTED AS
ENERGY PIVOTS DOWN TOWARD THE FOUR CORNERS REGION. THE 00Z
NON-NCEP MODELS OVERALL ARE A TAD SLOWER THAN THE 00Z NAM AND 00Z
GFS WITH THE HEIGHT FALLS, ALTHOUGH THE 00Z UKMET LOOKS TOO SLOW
BY THE END OF THE PERIOD. THE 00Z ECMWF IS STRONGLY SUPPORTED BY
THE 00Z GEFS MEAN AND 12Z ECENS MEAN, AND A BLEND OF THESE
SOLUTIONS WILL BE PREFERRED AS THIS BEST APPROXIMATES THE
MULTI-MODEL CONSENSUS.
..SHORTWAVE/CLIPPER LOW OVER MT/ND BY MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM BLEND
CONFIDENCE: ABOVE AVERAGE
THE GUIDANCE SUPPORTS A SHARPLY AMPLIFIED LARGE SCALE FLOW PATTERN
ACROSS NORTH AMERICA BY MONDAY WITH A STRONG DEEP LAYER RIDGE OVER
WESTERN NORTH AMERICA AND A DEEP TROUGH/VORTEX EVOLVING DOWN
ACROSS SOUTH-CENTRAL CANADA AND PORTIONS OF THE CENTRAL U.S. THERE
WILL BE A VIGOROUS SHORTWAVE/JET-STREAK DIVING SOUTHEAST TOWARD
THE NORTHERN HIGH PLAINS ON MONDAY WHICH WILL DRIVE A CLIPPER LOW
AND REINFORCING COLD FRONT SOUTH ACROSS MT/ND. THE 00Z NAM IS A
TAD FASTER WITH THE ENERGY/FORCING BY EARLY MONDAY COMPARED TO THE
GLOBAL MODEL CONSENSUS. A NON-NAM BLEND WILL BE PREFERRED AT THIS
POINT WITH THIS NEXT SYSTEM.
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML
ORRISON
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