892
FXUS10 KWNH 250503
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
102 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
..COMPLICATED INTERACTION WITH GULF OF MEXICO LOW CENTER
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z CMC/ECMWF/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 12Z NON-NCEP MODELS ARE ALL SLOWER, WITH
THE 12Z UKMET THE SLOWEST SOLUTION. THE CMC/ECMWF SOLUTIONS BETTER
APPROXIMATE THE MODEL CONSENSUS AND HAVE BETTER ENSEMBLE SUPPORT
VIA THE 18Z 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 12Z CMC/ECMWF/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, AND THE 00Z GFS SUGGESTS THE
SYSTEM WEAKENS AND DISSIPATES. HOWEVER, THE 12Z NON-NCEP GUIDANCE,
ALONG WITH THE 12Z ECENS MEAN AND 18Z 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 THE SYSTEM HAS OVER
THE GULF OF MEXICO, AND 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 12Z ECMWF/12Z ECENS MEAN
CONFIDENCE: SLIGHTLY 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. THE 12Z NON-NCEP MODELS OVERALL ARE A
TAD SLOWER THAN THE 00Z NAM AND 00Z GFS, ALTHOUGH THE 12Z UKMET
OVERALL LOOKS TOO SLOW. A BLEND OF THE 12Z ECMWF AND 12Z ECENS
MEAN WILL BE PREFERRED AS THIS CONSENSUS BEST APPROXIMATES THE
MULTI-MODEL CONSENSUS.
..SHORTWAVE/CLIPPER LOW OVER MT/ND BY MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM BLEND
CONFIDENCE: SLIGHTLY 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 EVOLVE DOWN ACROSS
SOUTH-CENTRAL CANADA AND PORTIONS OF THE CENTRAL U.S. THERE WILL
BE A VIGOROUS SHORTWAVE/JET-STREAM DIVING SOUTH EAST 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
STRONGER THAN THE GLOBAL MODEL SUITE OF GUIDANCE, AND SO A NON-NAM
BLEND WILL BE PREFERRED.
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML
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