Alert archive / Texas / Mesoscale Discussions in 2016

Mesoscale Discussion 124

February 23, 201610 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Feb 23, 2016, 12:11 PM CST for 10 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Feb 23, 2016, 12:11 PM CST (18:11 UTC)
Expired: Feb 23, 2016, 2:15 PM CST
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Chambers County, TX, Hardin County, TX, Harris County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Orange County, TX, Polk County, TX, San Jacinto County, TX, Tyler County, TX

The radar

The Houston radar (KHGX), 56 km from the middle of the area, began a volume at 18:14 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.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 6.2 hours before the alert went out and 168 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1 J/kg
Mixed-layer CIN: -116 J/kg
Mixed-layer LCL: 562 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 175 m²/s²
0-3 km storm-relative helicity: 258 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

599 
ACUS11 KWNS 231812
SWOMCD
SPC MCD 231811 
TXZ000-232015-

MESOSCALE DISCUSSION 0124
NWS STORM PREDICTION CENTER NORMAN OK
1211 PM CST TUE FEB 23 2016

AREAS AFFECTED...SERN TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 231811Z - 232015Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A MODEST RISK WILL EXIST FOR A FEW INSTANCES OF LARGE HAIL
AND STRONG TO DAMAGING WIND GUSTS THROUGH EARLY AFTERNOON OVER SERN
TX. SOME UNCERTAINTY STILL REMAINS REGARDING HOW MANY STORMS IF ANY
WILL DEVELOP...SO OVERALL THREAT IS SOMEWHAT CONDITIONAL. TRENDS
WILL CONTINUE TO BE MONITORED.

DISCUSSION...EARLY THIS AFTERNOON THE ATMOSPHERE IS DESTABILIZING IN
A NARROW CORRIDOR AHEAD OF A SEWD-ADVANCING COLD FRONT ACROSS SERN
TX. A NARROW ZONE OF CLEARING HAS DEVELOPED BENEATH MID-LEVEL
DRY-SLOT BEHIND LEAD SHORTWAVE TROUGH...BUT AHEAD OF MAIN VORT MAX.
ONLY MODIFIED CP AIR WITH LOW 60F DEWPOINTS RESIDE IN PRE-FRONTAL
WARM SECTOR. THESE FACTORS IN CONJUNCTION WITH COLD TEMPERATURES
ALOFT WITHIN UPPER JET EXIT REGION WILL RESULT IN AT LEAST MARGINAL
INSTABILITY WITH MLCAPE INCREASING TO 500-800 J/KG. VISIBLE IMAGERY
SHOWS CUMULUS INCREASING ALONG THE COLD FRONT...BUT IT STILL REMAINS
UNCERTAIN HOW MANY STORMS WILL INITIATE GIVEN PRESENCE OF MID-LEVEL
DRY SLOT AND TENDENCY FOR LOW-LEVEL WINDS TO VEER TO SWLY AHEAD OF
THE FRONT. SHOULD STORMS DEVELOP...THE STRONG UNIDIRECTIONAL DEEP
SHEAR WITH LONG HODOGRAPHS AND COLD AIR ALOFT WITH 7-7.5 C/KM
700-500 MB LAPSE RATES WILL SUPPORT A FEW ROTATING STORMS WITH A
THREAT FOR LARGE HAIL AND LOCALLY STRONG WIND GUSTS.

..DIAL/THOMPSON.. 02/23/2016

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

ATTN...WFO...LCH...HGX...

LAT...LON   29739562 30319537 30969497 30769395 29829383 29599444
            29299503 29409554 29739562

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 22, 6:24 PM CST	Mesoscale Discussion	SPC	Crane, Crockett, Edwards, Irion, Kimble, Kinney and 11 more	2 hr
Feb 22, 10:14 PM CST	Severe Thunderstorm Watch	SPC	Aransas, Atascosa, Bandera, Bastrop, Bee, Bexar and 40 more	8 hr
Feb 22, 11:46 PM CST	Mesoscale Discussion	SPC	Atascosa, Bandera, Bastrop, Bee, Bexar, Blanco and 31 more	89 min
Feb 23, 2:54 AM CST	Mesoscale Discussion	SPC	Aransas, Atascosa, Bee, Bexar, Brazoria, Calhoun and 19 more	96 min
Feb 23, 8:00 AM CST	Mesoscale Discussion	SPC	Chambers, Galveston, Jefferson, Orange	60 min

Nearby

Mesoscale Discussions in Texas, 2016 Every mesoscale discussion in 2016

Sources

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.