Mesoscale Discussion 7

Issued

Jan 9, 2012, 1:29 AM CST (07:29 UTC)

Expired

Jan 9, 2012, 4:00 AM CST

In force

3 hr

Issued by

the Storm Prediction Center

The Houston radar (KHGX), 52 km from the middle of the area, began a volume at 07:30 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.

854 
ACUS11 KWNS 090730
SWOMCD
SPC MCD 090729
LAZ000-TXZ000-091000-

MESOSCALE DISCUSSION 0007
NWS STORM PREDICTION CENTER NORMAN OK
0129 AM CST MON JAN 09 2012

AREAS AFFECTED...PORTIONS MIDDLE-UPPER TX COASTAL PLAIN.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 090729Z - 091000Z

MRGL SVR THREAT EXISTS OVER DISCUSSION AREA...INITIALLY FROM SMALL
SUPERCELLS IN WARM SECTOR OR ALONG FRONT DESCRIBED BELOW.  ALTHOUGH
LOW-PROBABILITY IN NATURE...PER 01Z CONVECTIVE OUTLOOK...A TORNADO
CANNOT BE RULED OUT.

ANALYZED 6Z SFC CHART SHOWED QUASISTATIONARY FRONTAL ZONE FROM
PROBABLE LOW OVER DATA VOID OF ERN COAHUILA...ENEWD OVER SRN
MAVERICK COUNTY...ACROSS SRN FRINGES SAT METRO AREA...TO NEAR
UTS...LFK AND NWRN LA.  MODIFIED RAOBS AND RUC SOUNDINGS SUGGEST
SFC-BASED EFFECTIVE INFLOW PARCELS WITH MINIMAL CINH FOR SFC DEW
POINTS MID 60S F...EXTENDING FROM THIS BAROCLINIC ZONE SWD OVER
MIDDLE-UPPER COAST.  CINH INCREASES SWWD FROM MIDDLE COAST TOWARD
RIO GRANDE BECAUSE OF STRONGER ELEVATED MIXED LAYER.  CINH ALSO
INCREASES IN LOWER-THETAE ENVIRONMENT S OF BOUNDARY OVER WRN LA AND
E-CENTRAL TX...AND OF COURSE NW OF FRONT.  LITTLE MOVEMENT OF
BOUNDARY IS EXPECTED DURING NEXT FEW HOURS...EXCEPT FOR SOME SWD
TRANSLATION OVER RIO GRANDE WITH FRONTAL-WAVE LOW PROGGED TO MOVE
SLOWLY ENEWD FROM MEX.  NET RESULT SHOULD BE RELATIVELY STEADY-STATE
AIR MASS OVER MID-UPPER COASTAL PLAIN WHERE WEAK WAA OFFSETS WEAK
DIABATIC SFC COOLING...MLCAPE REMAINS IN 500-1200 J/KG RANGE.
INVERSION LAYER NEAR 700 MB APPEARS TO BE WEAKENING BASED ON RECENT
INCREASE IN LTG PRODUCTION FROM CELLS IN THIS AREA.
KINEMATICALLY...CONDITIONS ARE FAVORABLE FOR STORM-SCALE ROTATION
WITH EFFECTIVE SHEAR MAGNITUDES 45-55 KT AND 0-1 KM AGL SRH 100-200
J/KG...BASED ON SFC-MODIFIED LDB PROFILER DATA AND RUC HODOGRAPHS.

POTENTIAL FOR ISOLATED DAMAGING GUSTS OR HAIL WILL BEGIN FROM W-E
LATER...FROM ABOUT 09Z ONWARD...AS PLUME OF COOLING/ASCENT ALOFT
SPREADS OVER AREA IN ADVANCE OF MID-UPPER LOW NOW APPARENT IN
MOISTURE CHANNEL IMAGERY OVER NRN CHIHUAHUA.

..EDWARDS.. 01/09/2012

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

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

LAT...LON   28109678 28179784 29179791 31299476 31109429 30469381
            29699387 29679405 29389474 29279472 28709568 28439637
            28319638 28109678

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.