138
FXUS10 KWNH 260641
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
241 AM EDT SAT OCT 26 2019
VALID OCT 26/0000 UTC THRU OCT 29/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..SHORTWAVE TROUGH CROSSING THE NORTHEAST ON SATURDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
A SHORTWAVE TROUGH CURRENTLY CLIPPING THE GREAT LAKES WILL ADVANCE
EAST ACROSS THE NORTHEAST EARLY SATURDAY MORNING AND THEN EXIT
THROUGH THE CANADIAN MARITIMES LATE IN THE DAY. ANY MODEL
DIFFERENCES WITH THIS SYSTEM ARE MINOR AND THEREFORE A GENERAL
MODEL BLEND WILL BE PREFERRED.
..AMPLIFIED TROUGH/CLOSED LOW LIFTING TOWARD THE OH VALLEY
..POST T.C. OLGA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
EFFECTIVE AT 03Z, T.S. OLGA HAS MERGED WITH THE STRONG COLD FRONT
ADVANCING EAST ACROSS THE LOWER MS VALLEY AND IS NOW AN
EXTRATROPICAL CYCLONE POSITIONED 170 MILES SOUTH-SOUTHEAST OF LAKE
CHARLES, LA. THE LATEST MODEL GUIDANCE SHOWS THE LOW CENTER
LIFTING NORTHEAST AND INLAND BY EARLY SATURDAY MORNING OVER
SOUTH-CENTRAL LA WITH THE SYSTEM THEN RAPIDLY LIFTING
NORTH-NORTHEAST TOWARD THE OH VALLEY LATER IN THE AFTERNOON AND
ACROSS THE LOWER GREAT LAKES REGION BY EARLY SUNDAY. THE
SUPPORTING UPPER TROUGH WILL BE ENCOUNTERING INCREASINGLY
CONFLUENT DOWNSTREAM FLOW ALOFT WITH TIME AND THE SYSTEM WILL
WEAKEN SUBSTANTIALLY LATE SUNDAY AS IT REACHES THE NORTHEAST. AS
THE ATTENDANT COLD FRONT REACHES THE EAST COAST LATE SUNDAY, THE
ORIGINAL LOW CENTER WILL DAMPEN OUT IN FAVOR OF A NEW AREA OF
CYCLOGENESIS NEAR SOUTHERN NEW ENGLAND. THIS LOW CENTER WILL MOVE
EAST AND OFFSHORE MONDAY AS THE REMNANT ENERGY ALOFT SHIFTS EAST
TOWARD THE WESTERN ATLANTIC AND CONTINUES TO WEAKEN. ALL OF THE
MODELS ARE IN GOOD AGREEMENT NOW WITH THE DETAILS OF THE MASS
FIELD EVOLUTION, AND SO A GENERAL MODEL BLEND WILL BE PREFERRED.
..DEEP TROUGH DIGGING ACROSS THE INTERMOUNTAIN WEST/PLAINS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GEFS/12Z ECENS MEAN
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
A STRONG DEEP LAYER RIDGE IS FORECAST TO EVOLVE OVER THE GULF OF
AK THIS WEEKEND AND TOWARD NORTHWEST CANADA EARLY NEXT WEEK WHICH
WILL ALLOW SHORTWAVE ENERGY TO DIG SOUTH ACROSS SOUTHWEST CANADA
AND THEN INTO INTERMOUNTAIN WEST AND HIGH PLAINS THROUGH THE
PERIOD, LEADING TO THE DEVELOPMENT OF A DEEP LONGWAVE TROUGH OVER
THE INTERMOUNTAIN WEST AND PLAINS BY TUESDAY. THE 00Z NON-NCEP
MODELS ARE ALL A LITTLE SLOWER THAN THE 00Z NAM AND 00Z GFS WITH
THE INITIAL SURGE OF ENERGY THAT PIVOTS ACROSS THE FOUR CORNERS
REGION SUNDAY THROUGH MONDAY. THE LATEST GEFS MEAN AND ECENS MEAN
SUPPORT A SOLUTION TOWARD THE MODESTLY MORE PROGRESSIVE CAMP, BUT
IT SHOULD BE NOTED THAT THE ECMWF DID TREND SLOWER AND AWAY FROM
THE NAM/GFS CAMP COMPARED TO ITS PREVIOUS RUN AND IS NOW ALIGNED
WITH THE LATEST UKMET/CMC SOLUTIONS. TOWARD THE END OF THE PERIOD
WITH THE DETAILS OF THE LONGWAVE TROUGH, THE NAM APPEARS TO BE
PERHAPS SLIGHTLY TOO DEEP OVER THE ROCKIES AND IMMEDIATE HIGH
PLAINS WITH THE ENERGY. ALSO, THE 00Z NON-NCEP MODEL SUITE VIA THE
UKMET, CMC AND ECMWF ARE ALL A TAD SLOWER THAN THE NAM AND GFS
WITH THE CORE OF HEIGHT FALLS/JET ENERGY DIGGING SOUTH ACROSS THE
NORTHERN ROCKIES. A BLEND OF THE LATEST GEFS MEAN AND ECENS MEAN
WILL BE PREFERRED TO ACCOUNT FOR THE RELATIVELY MODEST MODEL
SPREAD.
..SHORTWAVE/CLIPPER LOW OVER MT/ND BY MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
AS THE HIGHLY AMPLIFIED DEEP LAYER FLOW PATTERN EVOLVES ACROSS
NORTH AMERICA EARLY NEXT WEEK, THE GUIDANCE FAVORS A VIGOROUS
SHORTWAVE/JET-STREAK DIVING SOUTHEAST TOWARD THE NORTHERN HIGH
PLAINS ON MONDAY WHICH WILL DRIVE A CLIPPER LOW AND REINFORCING
COLD FRONT SOUTHEAST ACROSS MT/ND. THE LATEST NON-NCEP MODEL SUITE
DID TREND A TAD SLOWER AND IS AGAIN A LITTLE SLOWER THAN THE NAM
AND GFS, BUT FOR NOW, A GENERAL MODEL BLEND WILL CONTINUE TO BE
PREFERRED.
..SURFACE COLD FRONT OVER THE LOWER/MID MS VALLEY BY TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GEFS/12Z ECENS MEAN
CONFIDENCE: AVERAGE
AS THE DEEP LONGWAVE TROUGH EJECTS OUT OVER THE PLAINS SUNDAY AND
MONDAY, A COLD FRONT WILL SETTLE WELL SOUTH AND EAST, AND WILL BE
APPROACHING THE LOWER/MIDDLE MS VALLEY REGION LATE MONDAY AND
TUESDAY. SPREAD INCREASES WITH THE TIMING OF THE FRONT AS THE 00Z
GFS BECOMES MORE PROGRESSIVE THAN THE REMAINING GUIDANCE.
MEANWHILE, THE 00Z UKMET BECOMES THE SLOWEST. THERE IS ALSO SOME
SUPPORT FOR A WEAK WAVE OF LOW PRESSURE TO DEVELOP ALONG THE FRONT
AND LIFT UP ACROSS THE GREAT LAKES REGION BY THE END OF THE
PERIOD. THE BETTER MODEL CLUSTERING WITH THE SURFACE FRONT AND THE
SURFACE WAVE IS WITH THE LATEST GEFS MEAN AND ECENS MEAN, SO A
BLEND OF THESE SOLUTIONS WILL BE PREFERRED.
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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