MESO: Mesoscale Discussion 2064

ACUS11 KWNS 040649
SWOMCD
SPC MCD 040648
TXZ000-040845-

MESOSCALE DISCUSSION 2064
NWS STORM PREDICTION CENTER NORMAN OK
0148 AM CDT SUN OCT 04 2009

AREAS AFFECTED...S CNTRL THROUGH SERN TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 040648Z - 040845Z

THREAT FOR A BRIEF ISOLATED TORNADO OR TWO WILL PERSIST NEXT FEW
HOURS FROM S CNTRL THROUGH SERN TX. AT THIS TIME...OVERALL THREAT
APPEARS CONDITIONAL...AND A WW ISSUANCE IS UNLIKELY UNLESS TRENDS
BEGIN TO SUGGEST AN INCREASE IN STORM INTENSITY/ORGANIZATION.

EARLY THIS MORNING A STATIONARY FRONT EXTENDS FROM SERN TX JUST
SOUTH OF HOUSTON WWD TO NEAR COTULLA. LATEST OBJECTIVE ANALYSIS
INDICATES A RESERVOIR OF MODERATE INSTABILITY IN S TX WARM SECTOR
WHERE MID TO UPPER 70S DEWPOINTS EXIST. INSTABILITY BECOMES
INCREASINGLY MARGINAL WITH NWD EXTENT ONTO COOLER SIDE OF THE FRONT.
THERMODYNAMIC PROFILES IN THIS REGION EXHIBIT WEAK LAPSE RATES AND
DEEP MOISTURE WITH PRECIPITABLE WATER IN EXCESS OF 2 INCHES
CHARACTERISTIC OF A TROPICAL ENVIRONMENT. NUMEROUS STORMS WILL
CONTINUE THROUGH THE MORNING ACROSS S-CNTRL...CNTRL AND SERN TX
WITHIN BROAD ZONE OF LOW LEVEL WARM ADVECTION AND ISENTROPIC
LIFT...PRIMARILY NORTH OF THE STATIONARY FRONT. VWP DATA CONTINUE TO
INDICATE SIZEABLE LOW LEVEL HODOGRAPHS WITH 0-1 KM STORM RELATIVE
HELICITY FROM 200-300 M2/S2 NEAR AND NORTH OF THE FRONT WHERE LOW
LEVEL WINDS ARE BACKED TO ELY. HOWEVER...STABLE LAYER NEAR THE
SURFACE SUGGESTS CONVECTION DEVELOPING NORTH OF THE FRONT MAY BE
SLIGHTLY ELEVATED AND EFFECTIVE STORM RELATIVE HELICITY IS PROBABLY
LESS THAN 200 M2/S2. SOME UPDRAFT ROTATION WILL LIKELY CONTINUE WITH
STORMS DEVELOPING WITHIN THIS ENVIRONMENT EARLY THIS MORNING AND AN
ISOLATED TORNADO OR TWO CANNOT BE RULED OUT. HOWEVER...MARGINAL
LAPSE RATES...AN OBSERVED WEAKNESS IN THE WIND PROFILES BETWEEN 2
AND 3 KM AND NEAR SURFACE STABLE LAYER SHOULD SERVE AS POTENTIAL
LIMITING FACTORS FOR A MORE ROBUST SEVERE THREAT.

..DIAL.. 10/04/2009

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

ATTN...WFO...HGX...CRP...EWX...

LAT...LON 29029541 28649759 28619963 29399959 29649905 29689708
29579545 29029541

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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.