Mesoscale Discussion 119

Issued

Feb 15, 2012, 3:14 PM CST (21:14 UTC)

Expired

Feb 15, 2012, 4:45 PM CST

In force

91 min

Issued by

the Storm Prediction Center

The Lake Charles radar (KLCH), 127 km from the middle of the area, began a volume at 21:16 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.

859 
ACUS11 KWNS 152115
SWOMCD
SPC MCD 152114
MSZ000-ARZ000-LAZ000-TXZ000-152245-

MESOSCALE DISCUSSION 0119
NWS STORM PREDICTION CENTER NORMAN OK
0314 PM CST WED FEB 15 2012

AREAS AFFECTED...SOUTHEAST TX TO LA AND SOUTHERN AR/SOUTHWEST MS

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 152114Z - 152245Z

BOUTS OF ISOLATED SEVERE HAIL/GUSTY WINDS MAY PERSIST ACROSS
NORTHERN/CENTRAL PORTIONS OF LA INTO ADJACENT PARTS OF AR/MS THROUGH
LATE AFTERNOON. A SEVERE THREAT /AND HEAVY RAINFALL/ MAY ALSO
INCREASE TO A DEGREE THROUGH MID/LATE AFTERNOON ACROSS COASTAL
SOUTHEAST TX. A WATCH IS NOT CURRENTLY ANTICIPATED IN EITHER
CASE...BUT THE NEED FOR A WATCH CANNOT BE RULED OUT ACROSS SOUTHEAST
TX IF A CONVECTIVE UPSWING OCCURS.

AT MID-AFTERNOON...A WELL-SUSTAINED/INCREASINGLY ORGANIZED AND
MAINLY ELEVATED CONVECTIVE QUASI-LINEAR COMPLEX CONTINUES TO
STEADILY EXPAND/PROGRESS EAST-NORTHEASTWARD INTO NORTHERN/CENTRAL
LA. ON THIS NORTH AND EAST PERIPHERY OF THIS MCS...SUSTAINED
ASCENT/WARM ADVECTION AND THE PRESENCE OF WEAK ELEVATED BUOYANCY MAY
CONTINUE TO SUPPORT SOME SEVERE HAIL THREAT...ALTHOUGH SUCH A RISK
WILL TEND TO REMAIN EPISODIC/MARGINAL IN NATURE. AN EXPANDING MCS
COLD POOL AND THE INCREASINGLY ORGANIZED NATURE OF THE MCS
/INCLUDING APPARENT MCV TENDENCIES/ LEADS CREDENCE TO SOME POTENTIAL
FOR STRONG GUSTY WINDS...ALTHOUGH THE ELEVATED NATURE OF THE MCS AND
MODEST LAPSE RATES/BUOYANCY AHEAD OF IT SHOULD CONTINUE TO TEMPER
POTENTIAL FOR SEVERE-CALIBER DOWNDRAFTS...EVEN WHERE MODEST CLOUD
BREAKS AND SURFACE HEATING /AROUND 70 F/ ARE OCCURRING IN
SOUTH-CENTRAL LA.

FARTHER SOUTHWEST ACROSS THE COASTAL PLAIN OF SOUTHEAST TX...MOIST
LOW-LEVEL CONFLUENCE IMMEDIATELY AHEAD OF A SLOWLY ADVANCING PACIFIC
COLD FRONT WILL CONTINUE TO SUPPORT CONVECTIVE REGENERATION WITH A
SOUTHWEST-NORTHEAST ORIENTED CORRIDOR. ALONG WITH A SUSTAINED HEAVY
RAINFALL THREAT...SOME SURFACE BASED SEVERE THREAT COULD MATERIALIZE
ON THE SOUTHWEST FLANK OF THE CURRENT MCS WHERE THE AIRMASS HAS
DESTABILIZED /750-1500 J PER KG/ AMID A VERY MOIST AIRMASS /NEAR 70F
SURFACE DEWPOINTS/ AND LIMITED CLOUD BREAKS. WHILE THE COMBINATION
OF VERTICAL SHEAR/INSTABILITY COULD SUPPORT A SEVERE THREAT
INCLUDING SUPERCELLS...PERSISTENT CLOUD COVER AND MODEST CONVERGENCE
AMID NEBULOUS LARGE SCALE INFLUENCES ARE CONTRIBUTING TO UNCERTAINTY
TO THE EXTENT/LIKELIHOOD OF THE SEVERE RISK.
NONETHELESS...CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED FOR
THE POSSIBILITY OF AN INCREASING SEVERE THREAT ACROSS SOUTHEAST TX
THIS AFTERNOON.

..GUYER.. 02/15/2012

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

ATTN...WFO...JAN...LIX...LZK...LCH...SHV...HGX...EWX...

LAT...LON   29349685 30069648 30459575 31299346 33899244 33529103
            30639163 30349304 29759452 28759612 29349685

Mesoscale Discussions in Louisiana, 2012Mesoscale Discussions in Texas, 2012Mesoscale Discussions in Arkansas, 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.