Alert archive / Texas / Mesoscale Discussions in 2016

Mesoscale Discussion 9

January 9, 201613 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jan 9, 2016, 1:17 AM CST for 13 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jan 9, 2016, 1:17 AM CST (07:17 UTC)
Expired: Jan 9, 2016, 3:45 AM CST
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Brazos County, TX, Burleson County, TX, Grimes County, TX, Hardin County, TX, Jasper County, TX, Liberty County, TX, Montgomery County, TX, Polk County, TX, San Jacinto County, TX, Tyler County, TX, Walker County, TX, Waller County, TX, Washington County, TX

The radar

The Houston radar (KHGX), 119 km from the middle of the area, began a volume at 07:20 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 00:00Z, 7.3 hours before the alert went out and 223 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: 1021 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 665 m above ground
0-6 km bulk shear: 71 kt
0-1 km storm-relative helicity: 201 m²/s²
0-3 km storm-relative helicity: 240 m²/s²
Significant tornado parameter: 1.1
Supercell composite: 7.8

Open this sounding in Storm Lab

The text

As transmitted.

540 
ACUS11 KWNS 090718
SWOMCD
SPC MCD 090717 
TXZ000-090945-

MESOSCALE DISCUSSION 0009
NWS STORM PREDICTION CENTER NORMAN OK
0117 AM CST SAT JAN 09 2016

AREAS AFFECTED...PART OF SOUTHEAST TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 090717Z - 090945Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...AN ISOLATED HAIL THREAT /HAIL SIZE AROUND 1 INCH IN
DIAMETER WITH THE STRONGEST STORMS/ WILL REMAIN POSSIBLE THROUGH THE
OVERNIGHT TO EARLY SATURDAY MORNING ACROSS PART OF SOUTHEAST TX. 
LIMITED COVERAGE OF THIS THREAT PRECLUDES WW ISSUANCE.

DISCUSSION...SINCE 0530Z...MOSAIC RADAR IMAGERY SHOWED AN INCREASE
IN TSTM DEVELOPMENT AND INTENSITY...WITH THIS SMALL CLUSTER OF
STORMS MOVING THROUGH WESTERN WASHINGTON...BURLESON AND BRAZOS
COUNTIES AT 0705Z.  THIS ACTIVITY APPEARS TO HAVE FORMED NEAR THE
INTERSECTION OF THE PACIFIC COLD FRONT AND DRY LINE...AND ALONG THE
LEADING EXTENT OF DEEP FORCING FOR ASCENT ATTENDANT TO A SHORTWAVE
TROUGH TRACKING ACROSS CENTRAL TX.  ALTHOUGH THIS ACTIVITY IS MOVING
INTO A MORE MOIST ENVIRONMENT...COOLING SURFACE TEMPERATURES /GIVEN
TIME OF DAY/ SHOULD CONTINUE TO RESULT IN THESE STORMS BEING
ELEVATED AS SUGGESTED BY 05Z RAP FORECAST SOUNDINGS.  THE
COMBINATION OF STRONG FORCING FOR ASCENT WITH THE SHORTWAVE
TROUGH...THE PRESENCE OF STEEP MIDLEVEL LAPSE RATES AND COLD 500-MB
TEMPERATURES /-22 TO -26 C/...MUCAPE OF 500-1000 J/KG...AND
STRENGTHENING 500-MB WINDS/CLOUD-LAYER SHEAR SUPPORT ADDITIONAL
SUSTAINED ELEVATED UPDRAFTS WITH A HAIL THREAT.

THE 00Z 4-KM NAM/WRF-NSSL EACH SHOWED A SMALL CLUSTER OF STORMS
TRACKING TO THE EAST/EAST-NORTHEAST ACROSS SOUTHEAST TX THROUGH 11Z
BEFORE DIMINISHING NEAR THE SABINE RIVER.  THIS GUIDANCE CONFIRMS
THE CONCLUSIONS FROM THE OBSERVATIONAL AND DIAGNOSTIC DATA FOR A
SMALL CLUSTER OF STORMS POSING AN ISOLATED HAIL THREAT.  HOWEVER...
GIVEN THE LIMITED AREAL COVERAGE...A SEVERE THUNDERSTORM WATCH IS
NOT WARRANTED.

..PETERS/EDWARDS.. 01/09/2016

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

ATTN...WFO...LCH...SHV...HGX...EWX...

LAT...LON   30589659 30829617 30999525 31159461 31209400 31049374
            30509387 30169458 29989537 29919593 29919641 29969676
            30039683 30589659

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 8, 6:31 PM CST	Mesoscale Discussion	SPC	Angelina, Brazoria, Chambers, Cherokee, Fort Bend, Galveston and 22 more	119 min
Jan 8, 9:52 PM CST	Mesoscale Discussion	SPC	Orange	83 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.