036
FXUS10 KWNH 100432
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1232 AM EDT FRI APR 10 2020
VALID APR 10/0000 UTC THRU APR 13/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION...WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..DEEP CYCLONE IMPACTING THE NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
AN ANOMALOUSLY DEEP CLOSED LOW CROSSING THE GREAT LAKES WILL
DEEPEN AND TAKE ON A NEGATIVE TILT AS IT APPROACHES THE NORTHEAST
THIS AFTERNOON/EVENING. MEANWHILE, LOW PRESSURE CROSSING THE
INTERIOR OF NY STATE AND NEW ENGLAND WILL CONSOLIDATE OVER COASTAL
AREAS OF MAINE THIS EVENING AND DEEPEN INTO AN INTENSE LOW CENTER.
THE LATEST/00Z GFS ALIGNS FAIRLY WELL WITH THE REST OF THE
GUIDANCE WITH THE DEPTH OF THE SURFACE OFF THE COAST AS WELL AS
THE TRACK AS IT MOVES NORTHEASTWARD. SO OVERALL GIVEN THE
INCREASING TIGHTNESS IN THE MODEL SPREAD, WILL SIDE WITH A GENERAL
MODEL BLEND FOR THIS CYCLE.
...SLOW-MOVING CLOSED LOW ACROSS THE SOUTHWEST, DEEPENING LOW
MID-MS TO LOWER OH VALLEY DAY 3...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z ECMWF/ECENS MEAN BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
LARGE, SLOW-MOVING CUT OFF SOUTHERN STREAM LOW OVER CALIFORNIA
WILL GRADUALLY MOVE TOWARD SOUTHERN AZ/NM OVER THE NEXT 24 HOURS
AND THEN SLOWLY OPEN UP AS IT EJECTS INTO THE SOUTHERN PLAINS IN
THE DAY 2/3 TIME FRAME. THE MAIN MODEL DIAGNOSTIC CHALLENGE OVER
THE LAST SEVERAL DAYS HAS BEEN THE FASTER GFS OUTLIER AS THE
SYSTEM MOVES INTO THE SOUTH-CENTRAL PLAINS. FOR THE 00Z GFS RUN,
ITS EVOLUTION HAS SLOWED TOWARD THE REST OF THE MODEL CONSENSUS.
THE 00Z GFS RUN IS SLOWER THAN ITS 18Z GEFS MEAN AND SPLITS THE
DIFFERENCE BETWEEN THE ECMWF AND ECENS. DESPITE THE IMPROVING
CONSENSUS, THE GFS PROBABLY IS STILL A BIT OF AN OUTLIER AND WILL
BE EXCLUDED FROM THE MODEL BLEND PREFERENCE.
AS THE UPPER LEVEL SYSTEM MOVES OUT INTO THE CENTRAL PLAINS, LOW
PRESSURE WILL DEEPEN AND TRACK FROM THE ARKLATEX REGION TOWARD THE
LOWER OHIO VALLEY ON DAY 3. MODEL SPREAD IN THE LOW
TRACK/POSITIONS VARY FROM A NORTH/NORTHWEST OUTLIER IN THE 12Z
CMC/NAM TO A SLOWER AND FURTHER SOUTH ECMWF SOLUTION. THE SLOWER,
MORE SOUTHERN TRACK IS PREFERRED GIVEN THE PREFERENCE FOR THE
UPPER LEVEL SHORTWAVE, SO WILL EXCLUDE THE NAM/CMC FROM THE BLEND
CHOICE AS WELL.
..UPPER LEVEL TROUGH/COLD FRONT REACHING THE NORTHWEST
..DROPPING THROUGH THE NORTHERN PLAINS/MIDWEST ON SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...LED BY 18Z GEFS/12Z ECENS
CONFIDENCE: ABOVE AVERAGE
SHORTWAVE ENERGY ALONG THE SOUTHERN COAST OF ALASKA WILL PROGRESS
EASTWARD TO THE YUKON TERRITORY, AND WITH THE ACCELERATING/EXITING
JET, THE UPSTREAM RIDGE WILL BREAK DOWN AND ALLOW FOR GREATER
PROPAGATION EAST AND THEN SOUTHWARD ACROSS SOUTHWESTERN CANADA.
CONVERSELY, THIS WILL ALLOW THE EASTERN PACIFIC RIDGE TO BUILD,
HELPING TO CARVE OUT A LONGWAVE TROUGH OVER MUCH OF THE CENTRAL US
BY DAY 3 AND BEYOND. WITH THE INCREASINGLY AMPLIFIED PATTERN,
THERE IS FAIRLY GOOD CONSENSUS IN THE MODEL DEPICTION AND WITH THE
LATEST/00Z GUIDANCE, ONLY MINOR DIFFERENCES WERE NOTED. THE SPREAD
BETWEEN THE 00Z GFS, 12Z ECMWF AND THEIR RESPECTIVE ENSEMBLE MEANS
IS MINIMAL. A GENERAL MODEL BLEND FOR MASS FIELDS IS SUFFICIENT.
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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