601
FXUS10 KWNH 261847
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
246 PM EDT TUE MAY 26 2020
VALID MAY 26/1200 UTC THRU MAY 30/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
OVERALL PATTERN ACROSS THE CONTINENTAL U.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: MODERATE-HIGH
A SHORTWAVE TROUGH CURRENTLY OVER THE NORTHERN PLAINS WILL BE
GETTING ABSORBED INTO THE WESTERLIES ACROSS SOUTHERN CANADA BY
TUESDAY NIGHT. BY WEDNESDAY, THE MODELS SUPPORT AMPLIFICATION OF
A NEW NORTHERN STREAM TROUGH OVER SOUTHERN CANADA AND THE NORTHERN
PLAINS, AND THEN MOVE ACROSS THE UPPER MIDWEST BY THURSDAY. THIS
WILL SUPPORT SURFACE LOW PRESSURE ACROSS SOUTHERN CANADA WITH A
TRAILING COLD FRONT THAT WILL BE CROSSING THE NORTHERN PLAINS AND
UPPER MIDWEST. THE MODEL SPREAD THROUGH THE PERIOD IS RATHER
MODEST, AND SO A GENERAL MODEL BLEND WILL BE PREFERRED.
ACROSS THE SOUTH-CENTRAL U.S., THE MODELS ALL AGREE IN DEVELOPING
A CUT-OFF UPPER LOW OVER NORTHERN TEXAS BY LATE TUESDAY. THIS
UPPER LOW SHOULD THEN DRIFT VERY SLOWLY EASTWARD ACROSS THE
ARKLATEX REGION BY WEDNESDAY. ON THURSDAY, IT SHOULD CROSS THE
MID-SOUTH, BUT THE GUIDANCE SUPPORTS IT BEGINNING TO SLOWLY WEAKEN
AND ELONGATE EAST-NORTHEASTWARD TOWARD THE LOWER OHIO AND
TENNESSEE VALLEYS BY FRIDAY AS IT COMES UNDER INFLUENCE OF THE
NORTHERN STREAM TROUGH CROSSING THE UPPER MIDWEST. MODEL MASS
FIELD SPREAD IS MINIMAL THROUGH THE MAJORITY OF THE FORECAST
PERIOD, AND THEN THE NAM AND GFS REMAIN MORE AMPLIFIED THAN THE
NON-NCEP GUIDANCE FOR THE DAY 3 PERIOD.
TO THE SOUTH AND WEST OF THE EVOLVING RIDGE EAST COAST RIDGE WILL
BE A LOW TO MID-LEVEL TROUGH AXIS WHICH IS EXPECTED TO LIFT
NORTHWARD THROUGH THE EASTERN GULF OF MEXICO AND THE FLORIDA
PENINSULA GOING THROUGH TUESDAY EVENING. BY MID-WEEK, THIS ENERGY
WILL BE ADVANCING NORTH ACROSS THE SOUTHEAST AND THE SOUTHERN
APPALACHIANS WITHIN DEEP LAYER SOUTHERLY FLOW SITUATED BETWEEN THE
DEEP UPPER LOW APPROACHING THE MID-SOUTH AND THE BUILDING RIDGE
OVER THE WESTERN ATLANTIC. MULTIPLE WAVES OF LOW PRESSURE ARE
EXPECTED TO EVOLVE WITH THIS SYSTEM WITH ONE LOW LIFTING NORTH
ACROSS THE EASTERN GULF OF MEXICO, AND ANOTHER NEAR THE EAST COAST
OF FLORIDA. THE ONE ALONG THE EAST COAST OF FLORIDA IS EXPECTED
TO LIFT NORTHWARD TO COASTAL AREAS OF GEORGIA AND SOUTH CAROLINA
GOING THROUGH WEDNESDAY BEFORE THEN ADVANCING INLAND. WITH THE
EXCEPTION OF THE 12Z ECMWF THAT IS WEST OF THE MODEL CONSENSUS
WITH THE LOW NEAR THE SOUTHEAST COAST, THE MODELS APPEAR TO BE IN
RELATIVELY GOOD AGREEMENT.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
HAMRICK/ORRISON
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