513
FXUS10 KWNH 241922
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
222 PM EST MON FEB 24 2020
VALID FEB 24/1200 UTC THRU FEB 28/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...CLOSED LOW AND ITS INTERACTION WITH AN UPSTREAM AMPLIFYING
NORTHERN STREAM WAVE ACROSS PLAINS/GREAT LAKES THROUGH TUESDAY...
...ASSOCIATED SURFACE LOW CROSSING THE MISSISSIPPI RIVER AND INTO
THE GREAT LAKES TUE/WED...
..DEVELOPING EAST COAST LOW WED NIGHT.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND THROUGH 27.00Z, 12Z
ECMWF/UKMET/GFS BLEND THEREAFTER
CONFIDENCE: AVERAGE TO SLIGHTLY BELOW AVERAGE AFTER 27.00Z
19Z UPDATE: THE ECMWF CONTINUED ITS TREND A BIT TO THE
SOUTH/SOUTHEAST WITH THE UPPER LEVEL ENERGY ACROSS PORTIONS OF THE
MIDWEST FOR DAY 2 AND REMAINS ON THE WEAKER/LESS DEEP SIDE
COMPARED TO THE GFS. THE ECMWF IS ALSO FAIRLY SIMILAR TO THE UKMET
POSITION WITH THE 500 MB LOW, WHICH SEEMS TO BE WHERE THE GFS IS
TRYING TO TREND TO. SO THE BLEND PREFERENCE WAS UPDATED TO GO WITH
A GFS/ECMWF/UKMET BLEND AFTER 27.00Z.
WEAKENING UPPER LEVEL LOW CURRENTLY OVER PORTIONS OF THE SOUTHERN
MISSOURI OZARKS WILL FILL AS IT SLOWLY MOVES EASTWARD. A DIGGING
SHORTWAVE TROUGH OVER THE NORTHERN ROCKIES SEEN IN THE LATEST
WATER VAPOR IMAGERY IS FORECAST TO DIG TOWARD THE MID-MS VALLEY,
REINFORCING THE UPPER LEVEL ENERGY/TROUGH OVER THE CENTRAL US
THROUGH TUESDAY/TUESDAY PM. THIS IDEA IS WELL AGREED UPON BY THE
LATEST GLOBAL MODEL GUIDANCE SUCH THAT A GENERAL MODEL BLEND
THROUGH 26.00Z CAN BE UTILIZED.
BEYOND THAT TIME FRAME, THE FORECAST BECOMES LESS AGREEABLE AS
SEVERAL WAVES OF LOW PRESSURE TRACK FROM THE LOWER OHIO VALLEY,
GREAT LAKES, AND EVENTUALLY UP THE EAST COAST. THE INITIAL WAVE OF
LOW PRESSURE IS FORECAST TO MOVE FROM SOUTHERN MO TO SOUTHERN IN
AND WESTERN OH BEFORE DISSIPATING BY 26.12Z. THE APPROACH OF THE
SECONDARY UPPER LEVEL LOW ACTS TO REDEVELOP THIS FEATURE AND
DEEPEN IT AS MOVES THROUGH THE EASTERN GREAT LAKES. MEANWHILE,
ANOTHER SURFACE LOW DEVELOPS ACROSS THE MID-ATLANTIC AND TRACKS
ALONG THE EAST COAST INTO NEW ENGLAND. THE EXACT TIMING AND
PHASING OF ALL THESE FEATURES IS MESSY AND LESS CERTAIN AND THE
ENSEMBLE LOW TRACK PLOTS SHOW QUITE A BIT OF VARIETY BEYOND 60
HOURS (27.00Z).
THE PREFERENCE HAS BEEN TOWARD A MORE SUPPRESSED, SOUTHWARD
ADJUSTING SYSTEM/TRACK WHICH HAS BEEN THE IDEA SUPPORTED BY THE
ECMWF OVER THE LAST SEVERAL MODEL CYCLES. THE 12Z GFS, WHILE STILL
ON A NORTH/NORTHWEST BIAS AND ALSO FASTER, BUT HAS BEEN TRENDING
TOWARD THE ECMWF. THE GFS ALSO BEEN ADVERTISING A DEEPER/STRONGER
UPPER LEVEL LOW OVER THE LOWER GREAT LAKES MID-WEEK, WHILE THE
ECMWF HAS BEEN WEAKER. BOTH OPERATIONAL RUNS ARE IN LOCK STEP WITH
THEIR RESPECTIVE ENSEMBLE MEANS, THEY JUST HAVE SOME VARIABLE
TIMING DIFFERENCES. OVERALL, THE PREFERENCE IS TOWARD A ECMWF LIKE
SOLUTION THOUGH SOME COMPONENTS OF THE GFS LOOK PLAUSIBLE SO AFTER
60 HOURS, A BLEND OF THE ECMWF/GFS SEEMS LIKE A GOOD APPROACH AT
THIS TIME.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
TAYLOR
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