917
FXUS10 KWNH 080639
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
138 AM EST FRI NOV 08 2019
VALID NOV 08/0000 UTC THRU NOV 11/1200 UTC
..SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
...00Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES AND
CONFIDENCE...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..SHORTWAVES CUTTING INTO THE PACIFIC NORTHWEST RIDGE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z NAM, 00Z GFS, 00Z ECMWF BLEND WITH INCREASING
WEIGHT ON ECMWF THROUGH 12Z/11
CONFIDENCE: SLIGHTLY BELOW AVERAGE
..07Z UPDATE
SUBTLE CHANGES WERE MADE BY THE 00Z ECMWF/UKMET/CMC TOWARD THE
PREVIOUS PREFERENCE REGARDING THE TROUGHING DOWNSTREAM INTO THE
NORTH-CENTRAL U.S., BUT THE CHANGES WERE NOT LARGE ENOUGH TO
INCLUDE THE UKMET OR CMC IN THE PREFERENCE.
..PREVIOUS DISCUSSION FOLLOWS
THE LATEST GUIDANCE CONTINUES TO SHOW DIFFERENCES ON THE TEMPORARY
BREAKDOWN OF AN ANOMALOUS EASTERN PACIFIC RIDGE LATE TODAY INTO
SATURDAY. TRENDS SHOW CONVERGENCE IN SOLUTIONS COMPARED TO
YESTERDAY WITH DIFFERENCES WITH SHORTWAVE INTENSITY THROUGH
SATURDAY MORNING OFF OF THE NORTHWEST COASTLINE. THE 12Z UKMET
LOOKS TO BE THE MOST AGGRESSIVE WITH A FAVORED MODEL BLEND
REPRESENTED BY A 12Z ECMWF/00Z NAM/00Z GFS BLEND.
ATTENTION THEN TURNS DOWNSTREAM ACROSS THE NORTH-CENTRAL CONUS AS
TROUGHING ADVANCING SOUTH FROM CENTRAL CANADA REACHES THE NORTHERN
TIER ON SUNDAY. THE 00Z GFS HAS TRENDED TOWARD THE REMAINING MODEL
CONSENSUS COMPARED TO YESTERDAY BUT CONTINUES TO LIE ON THE
SOUTHERN EDGE OF THE ENSEMBLE SPREAD REGARDING 500 MB HEIGHT
AMPLIFICATION INTO THE NORTH-CENTRAL CONUS ON SUNDAY INTO MONDAY.
TIMING DIFFERENCES WITH A RELATED COLD FRONT THROUGH THE GREAT
PLAINS SHOW THE 00Z GFS AS THE FASTEST WHILE THE 12Z UKMET MAKES
UP THE OTHER END OF THE SPECTRUM WITH A SLOWER PROGRESSION. A
COMBINATION OF THE 12Z ECMWF/00Z NAM APPEARS TO BE A FAVORABLE
BLEND EARLY ON BUT THE 00Z NAM BEGINS TO LAG IN TIMING WITH
ELEMENTS OF THE GFS LOOKING MORE REASONABLE WHEN COMPARED TO THE
NAM. THE 12Z ECMWF IS A PREFERRED MIDDLE GROUND BY MONDAY MORNING
(12Z/11) BUT PIECES OF THE 00Z NAM AND 00Z GFS ARE USABLE
ELSEWHERE ACROSS THE PLAINS AND MIDWEST ON SUNDAY.
..REMAINDER OF OVERALL PATTERN ACROSS THE CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
..07Z UPDATE
NO SIGNIFICANT CHANGES WERE NOTED WITH THE 00Z ECMWF/UKMET/CMC
ACROSS THE REMAINDER OF THE U.S. COMPARED TO THEIR PREVIOUS 12Z
CYCLES, THEREFORE A GENERAL MODEL BLEND REMAINS AS THE PREFERENCE.
..PREVIOUS DISCUSSION FOLLOWS
A RIDGE-TROUGH PATTERN FROM WEST TO EAST STARTS OFF THE SHORT
RANGE PERIOD. THERE IS FLATTENING OF THE FLOW INTO SATURDAY
EVENING WITH A FAST UPPER LEVEL FLOW SETTING UP FROM THE PACIFIC
NORTHWEST INTO THE MID-ATLANTIC REGION. AMPLIFICATION REAPPEARS BY
MONDAY MORNING WITH STRONG RIDGING ALONG THE WEST COAST AND
DOWNSTREAM TROUGHING INTO THE NORTH-CENTRAL CONUS. A CLOSED LOW
WEST OF SOUTHERN CALIFORNIA IS FORECAST TO NEAR THE BAJA PENINSULA
THROUGH MONDAY MORNING.
REGARDING THE CLOSED LOW OFF OF THE BAJA PENINSULA AND AN EXITING
COLD FRONT FROM THE EAST LATER TODAY, THE MODELS ARE IN FAIR
AGREEMENT WITH A GENERAL MODEL BLEND RECOMMENDED.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
OTTO
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