364
FXUS10 KWNH 140653
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
252 AM EDT MON OCT 14 2019
VALID OCT 14/0000 UTC THRU OCT 17/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z FINAL MODEL EVALUATION WITH LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SOUTHERN CANADA LOW PRESSURE THROUGH TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE DEEP UPPER VORTEX AND SURFACE LOW OVER ONTARIO IS NOW MOVING
TOWARDS THE NORTHEAST AND SHOULD REACH NORTHERN QUEBEC BY TUESDAY
AFTERNOON. THE PRIMARY FRONT HAS STALLED OVER THE SOUTHEAST U.S.
WHILST THE SECONDARY FRONT WILL TRACK EASTWARD ACROSS THE
CENTRAL/NORTHERN APPALACHIANS ON MONDAY. A COUPLE IMPULSES RIDING
ALONG THE FRONT WILL ENHANCE PRECIPITATION TOTALS. THE GLOBAL
DETERMINISTIC MODEL GUIDANCE IS IN EXCELLENT AGREEMENT WITH THE
SYNOPTIC FEATURES AND THEREFORE A GENERAL MODEL BLEND IS PREFERRED.
SHORTWAVE TROUGH AND LOW ACROSS THE NORTH-CENTRAL U.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND THROUGH 00Z WEDNESDAY, THEN CMC/EC
MEAN
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
SHORTWAVE ENERGY ORIGINATING FROM THE PACIFIC NORTHWEST WILL CROSS
THE NORTHERN ROCKIES AND THEN THE NORTHERN PLAINS BY MONDAY NIGHT.
THE NORTHERN STREAM TROUGH WILL DEEPEN AND CLOSE OFF AS IT
APPROACHES THE UPPER MIDWEST AND GREAT LAKES, BECOMING A LONGWAVE
TROUGH OVER THE EASTERN U.S. WITH A NEGATIVE TILT BY WEDNESDAY
NIGHT. THIS WILL SPAWN A SURFACE LOW OVER THE UPPER MIDWEST ON
TUESDAY AND ALSO PHASE WITH THE SOUTHERN STREAM DISTURBANCE ACROSS
THE SOUTHEAST. THE RESULT WILL LIKELY BE A NOR'EASTER NEAR THE
NORTHEAST COAST BY WEDNESDAY NIGHT. THE MODELS ARE IN GOOD
AGREEMENT THROUGH TUESDAY EVENING, AFTER WHICH THE 00Z NAM AND
UKMET BECOMES MORE AMPLIFIED ALOFT, AND THE 00Z GFS BECOMES
SLIGHTLY FASTER. BY THE END OF THE FORECAST PERIOD, THE 00Z ECMWF
BECOMES MUCH STRONGER WITH THE SURFACE LOW NEAR NEW ENGLAND
THURSDAY MORNING, AND LIKEWISE THE NAM AS WELL. IN TERMS OF THE
ENSEMBLE MEANS, THE EC MEAN APPEARS CLOSER TO THE MODEL CONSENSUS
THAN THE GEFS MEAN. THEREFORE A BLEND OF THE CMC/EC MEAN SHOULD
WORK WELL AFTER 00Z WEDNESDAY AS A STARTING POINT.
SOUTHERN TIER SHORTWAVE AND RESULTING SURFACE LOW
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NAM/GFS/ECMWF
CONFIDENCE: AVERAGE
TROUGHING MOVING THROUGH THE WESTERN US WILL EVENTUALLY PINCH OFF
A SOUTHERN STREAM SHORTWAVE ACROSS SOUTHERN CALIFORNIA EARLY
MONDAY. THE MODELS HAVE COME INTO SLIGHTLY BETTER AGREEMENT WITH
THE AMPLITUDE AND AXIS ORIENTATION AS THE SHORTWAVE TRACKS ACROSS
THE FOUR CORNERS REGION. BY TUESDAY MORNING THIS WILL SPUR THE
DEVELOPMENT OF A SURFACE LOW ACROSS THE CENTRAL PLAINS THAT WILL
EVENTUALLY REACH THE SOUTHEAST U.S. BY WEDNESDAY AND MERGE WITH
THE NORTHERN STREAM SYSTEM BY EARLY THURSDAY. THE 00Z UKMET
BEGINS TO DIFFER BY 00Z WEDNESDAY WITH HIGHER HEIGHTS ACROSS THE
SOUTHERN PLAINS. THEREFORE A BLEND OF THE NAM/GFS/ECMWF SHOULD
SUFFICE AS A GOOD STARTING POINT.
PACIFIC NORTHWEST BY MIDWEEK
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: DETERMINISTIC MODEL BLEND
CONFIDENCE: AVERAGE
A STRONG STORM SYSTEM ORIGINATING FROM THE GULF OF ALASKA IS
EXPECTED TO BEGIN APPROACHING THE PACIFIC NORTHWEST COAST BY LATE
TUESDAY NIGHT AFTER A PERIOD OF RELATIVELY QUIET WEATHER EARLY IN
THE WEEK. ALTHOUGH THE SURFACE COLD FRONT IS FORECAST TO PASS
THROUGH THE REGION MID-WEEK, THE PARENT SURFACE LOW IS EXPECTED TO
REMAIN WELL TO THE NORTH ACROSS WESTERN CANADA. THERE ARE ONLY
MINOR MODEL DIFFERENCES WITH THE SYNOPTIC SCALE FEATURES AT THIS
TIME, SO A BLEND OF THE DETERMINISTIC GUIDANCE SHOULD WORK WELL.
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML
HAMRICK
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