Mesoscale Discussion 2140

Issued

Dec 9, 2012, 1:32 PM CST (19:32 UTC)

Expired

Dec 9, 2012, 2:30 PM CST

In force

58 min

Issued by

the Storm Prediction Center

Chance of a watch

20%

The Dallas/Ft Worth radar (KFWS), 135 km from the middle of the area, began a volume at 19:32 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.

014 
ACUS11 KWNS 091932
SWOMCD
SPC MCD 091932 
TXZ000-092030-

MESOSCALE DISCUSSION 2140
NWS STORM PREDICTION CENTER NORMAN OK
0132 PM CST SUN DEC 09 2012

AREAS AFFECTED...NERN TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 091932Z - 092030Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED SEVERE STORMS MAY BE POSSIBLE ACROSS E TX THIS
AFTERNOON. PRIMARY SEVERE DEVELOPMENT IS ANTICIPATED AS A COLD FRONT
PROGRESSES SEWD...GRADUALLY INCREASING COVERAGE OF STORMS AND
SUBSEQUENTLY WATCH PROBABILITIES LATER THIS EVENING.

DISCUSSION...PREFRONTAL STORMS ARE BEGINNING TO DEVELOP OVER NERN
TX. A CIRRUS STREAK EVIDENCED ON SATELLITE IMAGERY FROM SW TX NEWD
INTO SRN AR POSSIBLY INDICATES A SUBTROPICAL JET STREAK THAT THE
ONGOING THUNDERSTORMS MAY BE FORMING IN RESPONSE TO.
ADDITIONALLY...VISIBLE IMAGERY SHOWS A WAVY BOUNDARY JOINING THE
COLD FRONT NEAR SJT...BUT EXTENDING ROUGHLY ENEWD TO S OF TYR THAT
MAY PROVIDE A FOCUS FOR ADDITIONAL DEVELOPMENT OVER THE NEXT FEW
HOURS.

HOWEVER...UPDRAFTS HAVE BEEN DIFFICULT TO SUSTAIN THUS FAR AMIDST
OTHERWISE NEBULOUS SURFACE CONVERGENCE AND WEAK MID-LEVEL LAPSE
RATES. DIURNAL HEATING AND AT LEAST SOME CLEARING OF CLOUDS HAS
ALLOWED TEMPERATURES TO RISE INTO THE MID TO UPPER 70S F. GIVEN
SUSTAINED LOW-LEVEL MOISTURE CHARACTERIZED BY LOWER 60S DEW
POINTS...MODIFIED 12Z SOUNDINGS SUGGEST LITTLE CONVECTIVE INHIBITION
REMAINS.

HI RESOLUTION MODEL CONSENSUS SUGGESTS THAT MORE ORGANIZED
CONVECTION MAY AWAIT FRONTAL FORCING AND/OR EVENTUALLY FORM INTO
LOOSELY ORGANIZED CLUSTERS ACROSS E TX WHERE A FEW OF THE
AFOREMENTIONED SUBTLE BOUNDARIES EXIST. WITH GENERALLY WEAK
LOW-LEVEL FLOW...DMGG WIND POTENTIAL MAY INITIALLY BE LIMITED BUT
DIURNALLY DRIVEN BY STEEP LOW-LEVEL LAPSE RATES. ADDITIONALLY...WEAK
MID LEVEL LAPSE RATES SUGGEST ACHIEVING ROBUST UPDRAFTS MAY BE
DIFFICULT. HOWEVER...IF A STRONGER UPDRAFT CAN DEVELOP...STRONG DEEP
LAYER SHEAR WILL BE SUPPORTIVE OF ISOLATED SUPERCELLS CAPABLE OF
HAIL...WIND...AND PERHAPS A BRIEF TORNADO.

..DISPIGNA/HART.. 12/09/2012

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

ATTN...WFO...SHV...HGX...FWD...

LAT...LON   31349771 32319642 33119552 33659477 33439441 32729436
            31869490 31209575 30749695 30999754 31349771

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.