Tuesday, July 14, 2009

MESO: Mesoscale Discussion 1560

ACUS11 KWNS 142051
SWOMCD
SPC MCD 142050
NEZ000-142215-

MESOSCALE DISCUSSION 1560
NWS STORM PREDICTION CENTER NORMAN OK
0350 PM CDT TUE JUL 14 2009

AREAS AFFECTED...ERN NEB

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 142050Z - 142215Z

THE THREAT FOR SEVERE STORMS IS EXPECTED TO INCREASE LATE THIS
AFTERNOON INTO TONIGHT. CONVECTIVE TRENDS ARE BEING MONITORED FOR A
POSSIBLE WW.

VISIBLE SATELLITE IMAGERY SHOWS WELL-DEFINED CLOUD BAND ASSOCIATED
WITH COLD FRONT WHICH EXTENDED FROM APPROXIMATELY 30W YKN-20E
ONL-15E OF BBW AS OF 2030Z. FRONTAL MOTION WAS SEWD AT 15 KT.
PRE-FRONTAL AIR MASS OVER ERN NEB HAS WARMED THROUGH THE 80S AND
WHEN COUPLED WITH DEWPOINTS IN THE UPPER 60S TO LOWER
70S...ENVIRONMENT HAS BECOME MODERATE TO STRONGLY UNSTABLE WITH
MLCAPE OF 2000-3000 J/KG. RUC OBJECTIVE FIELDS AND VISIBLE
PRESENTATION OF BOUNDARY LAYER CLOUDS IN SATELLITE IMAGERY SUGGEST
THAT CAP IS WEAKEST OVER FAR NERN NEB...PROGRESSIVELY STRENGTHENING
WITH SEWD EXTENT TOWARD THE MO RIVER.

LATEST SHORT TERM MODEL GUIDANCE REMAINS CONSISTENT IN SUGGESTING
THAT ANY APPRECIABLE HEIGHT FALLS/DYNAMIC FORCING FOR ASCENT
ATTENDANT TO NRN PLAINS SHORT WAVE TROUGH WILL REMAIN N OF THE
NEB/SD BORDER. AS SUCH...THE HIGHEST PROBABILITY FOR STORM
INITIATION AND SUSTENANCE WILL BE ACROSS NERN NEB INTO NWRN
IA...WITH A DECREASING LIKELIHOOD SWD THROUGH E-CNTRL/SERN NEB.

TRENDS IN AREA VWPS/PROFILERS INDICATE GRADUAL VEERING TO LOW-LEVEL
WINDS IN ADVANCE OF SURFACE FRONT...RESULTING IN STRAIGHTER
HODOGRAPHS AND 35-45 KT OF DEEP LAYER SHEAR. AS SUCH...SETUP WILL
FAVOR THE DEVELOPMENT OF LINE SEGMENTS AND/OR SPLITTING SUPERCELLS
CAPABLE OF MAINLY LARGE HAIL AND DAMAGING WIND GUSTS.

..MEAD.. 07/14/2009

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FSD...OAX...GID...

LAT...LON 40809811 42099771 42459698 42179644 41289605 40659616
40219681 40259778 40809811

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