Mesoscale Discussion 122

Issued

Feb 17, 2012, 11:15 PM CST (05:15 UTC)

Expired

Feb 18, 2012, 12:45 AM CST

In force

90 min

Issued by

the Storm Prediction Center

The Austin/San Antonio radar (KEWX), 18 km from the middle of the area, began a volume at 05:15 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

692 
ACUS11 KWNS 180515
SWOMCD
SPC MCD 180515 
TXZ000-180645-

MESOSCALE DISCUSSION 0122
NWS STORM PREDICTION CENTER NORMAN OK
1115 PM CST FRI FEB 17 2012

AREAS AFFECTED...CENTRAL TX /INCLUDING TX HILL COUNTRY/ ENE TO PARTS
OF E TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 180515Z - 180645Z

TSTMS WILL CONTINUE TO INCREASE IN AREAL COVERAGE ACROSS MUCH OF
CENTRAL TX /INCLUDING THE HILL COUNTRY/ ENEWD INTO PARTS OF E TX
INTO THE OVERNIGHT PERIOD.  ISOLATED SEVERE HAIL /AOA 1 INCH
DIAMETER/ WILL BE POSSIBLE IN THE STRONGER SUSTAINED UPDRAFTS DURING
THE NEXT FEW HOURS...BUT OVERALL THREAT COVERAGE IS EXPECTED TO
REMAIN TOO LOW WITH NWD EXTENT TO WARRANT THE ISSUANCE OF A WW AT
THIS TIME.  HOWEVER...FARTHER S...A FURTHER INCREASE IN STORM
INTENSITIES/COVERAGE WITH ACTIVITY FROM MAVERICK-MEDINA COUNTIES MAY
PROMPT THE NEED FOR A WATCH ALONG AND JUST N OF THE 01Z SLIGHT RISK
AREA.

MID-LATE EVENING SURFACE ANALYSES SHOWED A WARM FRONT HAD MOVED NWD
A ROW OF COUNTIES IN DEEP S TX SINCE 00Z...WITH THE NEW POSITION
EXTENDING FROM ZAPATA TO KLEBERG COUNTIES...AND EWD INTO THE WRN
GULF OF MEXICO.  WSR-88D VADS AND WIND PROFILER DATA INDICATED A
25-30 KT SLY LLJ EXTENDING FROM BRO TO SAT RESULTING IN WAA ATOP A
STABLE BOUNDARY LAYER.  MEANWHILE...REGIONAL RADAR IMAGERY SHOWED
CLUSTERS OF TSTMS EXTENDING FROM LLANO COUNTY W/SWWD TO VAL VERDE
AND MAVERICK COUNTIES.  THIS ACTIVITY LIKELY IS ATTENDANT TO
STRONGER LARGE SCALE ASCENT BEGINNING TO SPREAD ACROSS TX WITH THE
APPROACH OF NRN MEXICO SHORTWAVE TROUGH.  ADDITIONAL EPISODIC
STRONGER STORMS WERE ALSO NOTED PRIMARILY WITHIN THE NERN EXTENT OF
THE WAA REGIME INVOF CLL.

CURRENT THINKING SUGGESTS ADDITIONAL SUSTAINED ELEVATED UPDRAFTS
/SIMILAR TO THE AFOREMENTIONED ACTIVITY OVER AND NE OF THE TX HILL
COUNTRY/ WILL DEVELOP INTO THE EARLY OVERNIGHT.  EFFECTIVE BULK
SHEAR ALREADY RANGING FROM 40-65 KT AND MUCAPE 500-1500 J/KG SHOULD
SUPPORT AN ISOLATED HAIL THREAT.  GREATER SEVERE WEATHER THREAT MAY
DEVELOP AFTER MIDNIGHT AS STRONGER HEIGHT FALLS SPREAD INTO
CENTRAL/S TX AHEAD OF THE UPSTREAM TROUGH...WITH THE EVENTUAL NEED
FOR A WW ACROSS THE SWRN-SRN EXTENT OF THE DISCUSSION AREA.

..PETERS.. 02/18/2012

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

ATTN...WFO...SHV...HGX...FWD...CRP...EWX...SJT...

LAT...LON   29909497 28989707 28539800 28149933 28129995 28580032
            29850078 30750014 31289854 31899528 31129487 29909497

Mesoscale Discussions in Texas, 2012Every mesoscale discussion in 2012

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.