170
FXUS10 KWNH 241622
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1222 PM EDT SUN MAY 24 2020
VALID MAY 24/1200 UTC THRU MAY 28/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING INITIAL PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SHORTWAVE TROUGH CROSSING THE GREAT LAKES THROUGH SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: HIGH
A RATHER COMPACT MID TO UPPER-LEVEL LOW CENTER CROSSING THE
MIDWEST THIS EVENING WILL BE ADVANCING ACROSS THE GREAT LAKES
REGION ON SUNDAY AND WEAKENING WITH TIME AS IT TRACKS OVER THE TOP
OF A STRENGTHENING DEEP LAYER RIDGE OVER THE SOUTHEAST U.S. ON
MONDAY, A WEAK REMNANT OF THIS ENERGY WILL CROSS THROUGH NORTHERN
NEW ENGLAND. THE MODELS ARE IN GOOD AGREEMENT WITH THIS SYSTEM,
AND SO A GENERAL MODEL BLEND WILL BE PREFERRED.
SYNOPTIC SCALE TROUGH OVER THE WEST EVOLVING INTO CLOSED LOW OVER
SOUTHERN PLAINS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z UKMET/ECMWF/EC MEAN BLEND
CONFIDENCE: AVERAGE
THE LATEST GUIDANCE SHOWS VERY GOOD AGREEMENT IN BRINGING A NEW
LARGE SCALE UPPER TROUGH AND ASSOCIATED CLOSED LOW IN ACROSS THE
INTERMOUNTAIN WEST THROUGH THE WEEKEND. BY MONDAY, THE MODELS
SUPPORT THIS DEEP TROUGH EDGING TOWARD THE PLAINS WITH ONE CLOSED
LOW CENTER EXITING THE NORTHERN ROCKIES AND CROSSING THE NORTHERN
HIGH PLAINS. MEANWHILE, A SECOND CLOSED LOW WILL BE ATTEMPTING TO
FOCUS OVER THE CENTRAL ROCKIES, AND BY TUESDAY THE GUIDANCE IS IN
REASONABLY GOOD AGREEMENT ON THE IDEA OF A NEW CLOSED LOW BECOMING
WELL-DEFINED OVER THE SOUTHERN PLAINS.
LEADING UP TO THIS CLOSED LOW EVOLUTION OVER THE SOUTHERN PLAINS,
THERE WILL BE A PAIR OF SHORTWAVE TROUGHS, ONE ON SUNDAY AND ONE
ON MONDAY, THAT WILL ROUND THE BASE OF THE LARGER SCALE TROUGH AND
LIFT NORTHEAST ACROSS THE SOUTHERN PLAINS. THE FIRST SHORTWAVE IS
EXPECTED TO EVOLVE OUT OF THE MCS ACTIVITY CURRENTLY IMPACTING
AREAS SOUTH-CENTRAL TX AND THE MIDDLE RIO GRANDE VALLEY. THE
SECOND AND MORE DOMINANT SHORTWAVE IS CURRENTLY SHOWING UP VERY
DISTINCTLY ACROSS THE SOUTHWEST U.S. AND NORTHWEST MEXICO, AND IS
MOVING STEADILY OFF TO THE EAST. THIS ENERGY WILL LIFT NORTHEAST
THROUGH SUNDAY NIGHT TOWARD THE LOWER MS VALLEY AS THE SECOND
UPSTREAM SHORTWAVE TROUGH ARRIVES AND ULTIMATELY FOSTERS THE UPPER
LOW DEVELOPMENT OVER THE SOUTHERN PLAINS BY TUESDAY.
MID-LEVEL TROUGH AND WEAK SURFACE LOW IMPACTING FLORIDA EARLY IN
THE WEEK
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z NAM/GFS/00Z ECMWF BLEND
CONFIDENCE: AVERAGE
AN UPPER LEVEL RIDGE WILL BE BUILDING ACROSS THE SOUTHEAST AND THE
EAST COAST THROUGH THE BEGINNING OF THE WEEK. SOUTH OF THE UPPER
RIDGE WILL BE A LOW-MID LEVEL TROUGH AXIS THAT WILL GRADUALLY LIFT
NORTHWARD TO THE EASTERN GULF OF MEXICO, WITH A WEAK SURFACE WAVE
OF LOW PRESSURE LIKELY DEVELOPING ALONG IT BY MONDAY. ALTHOUGH
THIS DOES NOT APPEAR PARTICULARLY IMPRESSIVE IN TERMS OF MASS
FIELDS, IT WILL BE SIGNIFICANT FOR QPF PURPOSES. GIVEN THAT THE
00Z UKMET IS MORE SUPPRESSED WITH THE 700 MB TROUGH ACROSS CUBA
AND THE FLORIDA STRAITS, THIS KEEPS THE HEAVIEST RAINFALL FARTHER
SOUTH THAN THE RELATIVELY WELL CLUSTERED NAM/GFS/ECMWF. THE 00Z
CMC ALSO APPEARS FARTHER SOUTH WITH ITS QPF AXIS ON DAY 2 ACROSS
SOUTH FLORIDA. AN INITIAL BLEND CONSISTING OF THE 12Z NAM/GFS/00Z
ECMWF SHOULD WORK WELL AND MAINTAINS GOOD CONTINUITY WITH EARLIER
PREFERENCES.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
HAMRICK
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