544
FXUS10 KWNH 130427
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1227 AM EDT MON APR 13 2020
VALID APR 13/0000 UTC THRU APR 16/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SOUTHERN STREAM SHORTWAVE LEADING TO INTENSE SURFACE LOW OVER
GREAT LAKES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
DEEPENING LOW PRESSURE OVER THE MID-MS TO LOWER GREAT LAKES WILL
SWING AN INTENSE COLD FRONT THROUGH THE EASTERN U.S. OVER THE NEXT
24-36 HOURS. THE LATEST DETERMINISTIC GUIDANCE SHOWS VERY GOOD
AGREEMENT IN THE UPPER LEVEL PATTERN AS WELL AS THE SURFACE LOW
TRACK AND DEPTH. WITH THE BETTER CONSOLIDATION IN THE MASS FIELDS
IN THE DAY 1/2 TIME FRAME, A GENERAL MODEL BLEND WILL BE MORE THAN
SUFFICIENT FOR THIS CYCLE.
AMPLIFYING UPPER TROUGH OVER THE NORTHERN U.S. THROUGH MIDWEEK
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND THROUGH 15.00Z; THEN NON-GFS BLEND
AFTER
CONFIDENCE: AVERAGE
REINFORCING LONGWAVE TROUGHING IS EXPECTED OVER THE NORTHERN U.S.
THROUGH MID-WEEK WITH MULTIPLE IMPULSES PIVOTING THROUGH THE FLOW.
IN THIS AMPLIFIED PATTERN, THE MODELS SHOW AVERAGE TO ABOVE
AVERAGE AGREEMENT IN THE LARGE SCALE PATTERN WITH ONLY MINOR
SPEED/TIMING DIFFERENCES THIS CYCLE. THE 00Z GFS IS FASTER THAN
THE OTHER DETERMINISTIC GUIDANCE AND ALSO LESS AMPLIFIED AS THE
TROUGH AXIS SWINGS THROUGH THE INTERMOUNTAIN WEST. WITH THE OTHER
GUIDANCE IN GOOD AGREEMENT, A NON-GFS BLEND AFTER 15.00Z IS
PREFERRED.
SHORTWAVE NEAR THE PACIFIC NORTHWEST BY MIDWEEK
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z ECENS/ECMWF AND 18Z GEFS BLEND
CONFIDENCE: AVERAGE
A CLOSED LOW OVER THE NORTH PACIFIC WILL ROUND THE PERIPHERY OF AN
UPPER LEVEL RIDGE AND THEN UNDERCUT TOWARD THE EASTERN PACIFIC
INTO MID-WEEK. GIVEN THE HIGHLY AMPLIFIED PATTERN, THERE IS
INCREASING TEMPORAL AND SPATIAL DIFFERENCES THAT DEVELOP IN THE
DAY 3 TIME FRAME. THE GFS IS ON THE FASTER ENVELOPE SPREAD WHILE
THE CMC IS ON THE SIDE. GIVEN THE SPREAD AND TIMING DIFFERENCES, A
PREFERENCE TOWARD THE ENSEMBLES REMAINS A GOOD APPROACH. A BLEND
OF THE 12Z ECENS/ECMWF AND 18Z GEFS MEAN OFFER REASONABLE
SOLUTIONS AT TIME.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
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