133
FXUS10 KWNH 101849
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
248 PM EDT TUE MAR 10 2020
VALID MAR 10/1200 UTC THRU MAR 14/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..CLOSED LOW AFFECTING THE SOUTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 12Z UKMET BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
A CLOSED LOW OFFSHORE OF SOUTHERN CALIFORNIA WILL SLOWLY MOVE
EASTWARD INTO THE SOUTHWEST WITH A FEW MID-LEVEL VORTICITY CENTERS
REVOLVING ABOUT THE COMMON CENTER OF THE LOW. OVERALL TRENDS IN
THE ENSEMBLES HAVE BEEN SLOWER WITH THE CLOSED LOW PROGRESSION
WITH DETERMINISTIC MODEL TRENDS A BIT MIXED. MINOR RUN TO RUN
DIFFERENCES WITH THE MAIN VORTICITY LOBES HAVE LED TO MORE
SIGNIFICANT DIFFERENCES WITH TIMING OF PRECIPITATION ACROSS THE
SOUTHWEST, BUT THE ONE MODEL THAT STANDS OUT THE GREATEST IS THE
12Z UKMET WITH A SLOWER PUSH TOWARD THE EAST. IT APPEARS ENSEMBLES
HAVE BEEN CONVERGING UPON AN COMMON SOLUTION REPRESENTED BY A
BLEND OF THE NON 12Z UKMET GUIDANCE.
...NORTHERN STREAM TROUGH TRACKING FROM THE NORTHERN ROCKIES,
UPPER MIDWEST TOWARD THE NORTHEAST THROUGH FRIDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/ECMWF/UKMET BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
A LOWER AMPLITUDE LONGWAVE TROUGH WILL TRACK THROUGH THE NORTHERN
CONUS FROM WEDNESDAY THROUGH FRIDAY. AT THE SURFACE, A COLD FRONT
WILL STEADILY TRACK TO THE EAST AND SOUTH. THE 12Z NAM APPEARS TOO
FAST WITH THE TROUGH PROGRESSION WHILE THE 12Z CMC TOO SLOW GIVEN
PLACEMENT OF THE REMAINING MODELS AND ENSEMBLE MEANS IN THE
MIDDLE. A BLEND OF THE 12Z GFS (SLIGHTLY FASTER) WITH THE 12Z
ECMWF AND 12Z UKMET APPEARS BEST FOR THIS SYSTEM WITH CONFIDENCE
SLIGHTLY ABOVE AVERAGE GIVEN THE RELATIVELY GOOD CONSISTENCY FOR
GUIDANCE IN THE MIDDLE OF THE TWO FASTER/SLOWER EXTREMES.
..ELSEWHERE ACROSS THE CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
ELSEWHERE ACROSS THE LOWER 48, A FEW LOW AMPLITUDE MID-LEVEL
SHORTWAVES WILL TRACK EASTWARD IN QUASI-ZONAL FLOW INITIALLY IN
PLACE FROM THE NORTHERN HIGH PLAINS INTO THE NORTHEAST WITH LITTLE
DIFFERENCE NOTED IN THE LATEST GUIDANCE. IN ADDITION, A SHORTWAVE
WILL AMPLIFY TOWARD THE PACIFIC NORTHWEST ON FRIDAY DOWNSTREAM OF
A HIGHLY AMPLIFIED RIDGE CENTERED OVER THE GULF OF ALASKA. THERE
ARE MINOR DIFFERENCES WITH THE LATITUDE OF A COMPACT VORTICITY MAX
LOCATED NEAR THE COAST OF WASHINGTON/OREGON ON FRIDAY, WITH THE
12Z NAM/GFS A LITTLE FARTHER NORTH COMPARED TO THE ____________
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
OTTO
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