929
FXUS10 KWNH 120457
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1156 PM EST MON NOV 11 2019
VALID NOV 12/0000 UTC THRU NOV 15/1200 UTC
..SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
...00Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES AND
CONFIDENCE...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..DEPARTING EAST COAST STORM SYSTEM TODAY/TONIGHT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
NO SIGNIFICANT DIFFERENCES WERE NOTED WITH THIS SYSTEM UNTIL AFTER
THE SURFACE LOW HAS EXITED NORTHWARD INTO THE CANADIAN MARITIMES.
THE 12Z UKMET TRACKS THE SURFACE-850 MB LOW FARTHER INLAND THAN
THE MODEL CONSENSUS, BUT GIVEN THIS DIFFERENCE HAS LITTLE TO NO
IMPACT ON THE LOWER 48, A GENERAL MODEL BLEND IS PREFERRED.
...SHORTWAVE TRACKING FROM THE NORTHWEST TO THE GREAT PLAINS FOR
WEDNESDAY AND GREAT LAKES FOR THURSDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
GOOD AGREEMENT WAS NOTED IN THE DETERMINISTIC AND ENSEMBLE
GUIDANCE REGARDING THIS SYSTEM. HOWEVER, THE 00Z GFS WAS SLIGHTLY
SLOWER THAN THE REMAINING CONSENSUS, BUT THIS DIFFERENCE IS SMALL
ENOUGH TO NOT BE A CONCERN WHEN USED AS PART OF A GENERAL MODEL
BLEND.
...WEAKENING CLOSED LOW CROSSING MEXICO AND POSSIBLE INTERACTION
WITH SHORTWAVE DROPPING SOUTHWARD FROM THE LOWER MISSISSIPPI
VALLEY ON FRIDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z ECMWF/UKMET BLEND
CONFIDENCE: SLIGHTLY BELOW AVERAGE
THE 00Z GFS IS SIGNIFICANTLY FASTER WITH THE CLOSED LOW CROSSING
MEXICO INTO THE GULF OF MEXICO, ON THE FASTEST EDGE OF THE LATEST
ENSEMBLE GUIDANCE. THE REMAINING DETERMINISTIC GUIDANCE IS IN GOOD
AGREEMENT WITH THE REMNANT CLOSED LOW/SHORTWAVE CROSSING
MEXICO/SOUTHERN TEXAS ON THURSDAY.
LARGER DIFFERENCES EXIST WITH MID-LEVEL VORTICITY DROPPING
SOUTHWARD (ORIGINATING FROM THE GULF OF ALASKA TUESDAY MORNING)
INTO THE CENTRAL PLAINS AND EVENTUALLY THE LOWER MISSISSIPPI
VALLEY THURSDAY NIGHT AS THE 00Z NAM AND 12Z CMC ARE FASTER
STARTING THURSDAY MORNING. DIFFERENCES WITH THE 00Z GFS REGARDING
THE SHORTWAVE TO THE SOUTH PRECLUDES ITS USABILITY ACROSS THE GULF
COAST/LOWER MISSISSIPPI VALLEY.
THE 12Z ECMWF/UKMET ARE IN FAIR AGREEMENT AND MATCH BEST TO THE
AGREEABLE ENSEMBLE MEANS WITH THE 500 MB VORTICITY WITHIN THE
TROUGH AXIS AND LOW LEVEL BAROCLINIC BOUNDARY IN THE GULF AND JUST
OFFSHORE OF THE SOUTHEAST COAST. BLENDING THE 12Z ECMWF/UKMET
SURFACE LOW POSITIONS ALONG THE FRONTAL BOUNDARY ARE BEST TO ALIGN
WITH THE MIDDLE OF THE LATEST ENSEMBLE SCATTER LOW PLOTS.
CONFIDENCE IS REDUCED GIVEN THE COMPLEXITY AND POTENTIAL
INTERACTIONS OF VARIOUS FEATURES DOWNSTREAM AND UPSTREAM.
...PAIR OF MID-LEVEL SHORTWAVES APPROACHING THE WEST COAST ON
THURSDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
A RELATIVELY WEAK MID-LEVEL SHORTWAVE IS EXPECTED TO APPROACH THE
OREGON/CALIFORNIA COASTLINES EARLY ON THURSDAY WHILE A SECOND
SHORTWAVE LURKS TO THE NORTH WITH A LIKELY DESTINATION OF
WASHINGTON/BRITISH COLUMBIA THURSDAY NIGHT. DESPITE SOME MINOR
TIMING DIFFERENCES OF THESE TWO FEATURES, AGREEMENT IS GOOD ENOUGH
TO WARRANT A GENERAL MODEL COMPROMISE WHICH ALIGNS WITH THE LATEST
ENSEMBLE MEANS.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
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