SWOMCD
SPC MCD 172320
IAZ000-MOZ000-NEZ000-180045-
MESOSCALE DISCUSSION 1855
NWS STORM PREDICTION CENTER NORMAN OK
0620 PM CDT FRI SEP 17 2010
AREAS AFFECTED...ERN NEB...WRN IA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 172320Z - 180045Z
PORTIONS OF ERN NEB AND WRN IA ARE BEING MONITORED FOR A SEVERE
THUNDERSTORM WATCH.
SURFACE ANALYSIS AT 23Z SHOWS A QUASI-STATIONARY FRONTAL BOUNDARY
EXTENDING NEWD OUT OF NWRN KS/SWRN NEB TOWARD OMA/W-CNTRL IA.
VISIBLE SATELLITE IMAGERY INDICATES CUMULUS FIELD ALONG THE BOUNDARY
IS BEGINNING TO DEEPEN SOMEWHAT OVER ERN NEB...WHERE WARMER SURFACE
AIR MASS /MID 80S F TEMPERATURES/ RESIDES. HOWEVER...19Z SPECIAL
SOUNDING FROM OAX SHOWS A SUBSTANTIAL EML CAPPING INVERSION LOCATED
OVER THE REGION...WHICH SUGGESTS THAT CONVECTIVE INITIATION MAY BE
TIED TO NOCTURNAL STRENGTHENING OF THE LOW-LEVEL JET...LEADING TO
ADDITIONAL CONVERGENCE AND WAA ALONG THE FRONTAL ZONE. THIS APPEARS
TO BE SUPPORTED BY SHORT TERM HI-RES MODEL GUIDANCE...WHICH BREAKS
OUT THUNDERSTORMS NEAR OMA BY 00-01Z.
THE PRESENCE OF STEEP MID-LEVEL LAPSE RATES /AOA 7.0 C PER KM IN THE
700-500 MB LAYER/ ATOP A FAVORABLY MOIST BOUNDARY LAYER
/CHARACTERIZED BY SFC DEWPOINTS IN THE MID 60S F/ IS AIDING IN THE
DEVELOPMENT OF STRONG POTENTIAL INSTABILITY /MLCAPE VALUES RANGING
FROM 1500 J PER KG OVER SWRN IA TO 2500 J PER KG OVER SERN
NEB...BASED ON SFCOA GUIDANCE/. IN ADDITION...AREA PROFILERS AND RUC
FORECAST SOUNDINGS SHOW EFFECTIVE BULK SHEAR VALUES RANGING FROM 40
KT ALONG AND N OF THE BOUNDARY TO 30-35 KT S OF THE BOUNDARY...WHICH
FAVORS ORGANIZED THUNDERSTORM DEVELOPMENT...INCLUDING POSSIBLE
SUPERCELLS. GIVEN THE STEEP LAPSE RATE ENVIRONMENT AND STRONG
EFFECTIVE BULK SHEAR /PARTICULARLY N OF THE FRONT/...THE THREAT FOR
LARGE TO POSSIBLY VERY LARGE HAIL WILL ACCOMPANY STRONGEST STORM
ACTIVITY. IN ADDITION...THOSE STORMS WHICH RESIDE CLOSE TO OR MOVE
SEWD INTO THE WARM SECTOR WOULD BE CAPABLE OF DAMAGING WIND GUSTS
AND PERHAPS A TORNADO.
..GARNER.. 09/17/2010
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...DMX...EAX...FSD...OAX...GID...LBF...
LAT...LON 42349700 42499491 41899388 40789415 40289645 40359781
40869845 41779831 42349700
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.
No comments:
Post a Comment