SWOMCD
SPC MCD 260031
ARZ000-LAZ000-TXZ000-OKZ000-260200-
MESOSCALE DISCUSSION 0272
NWS STORM PREDICTION CENTER NORMAN OK
0731 PM CDT FRI MAR 25 2011
AREAS AFFECTED...NCNTRL/NERN TX...SCNTRL/SERN OK...SWRN AR AND NWRN
LA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 260031Z - 260200Z
CURRENT POTENTIAL FOR A WW ISSUANCE ACROSS NCNTRL/NERN TX...
SCNTRL/SERN OK AND EWD TO SWRN AR/NWRN LA REMAINS CONDITIONAL BASED
ON TSTM DEVELOPMENT. HOWEVER...GIVEN THE AVAILABLE WARM SECTOR
INSTABILITY/SHEAR PARAMETERS...STORMS WILL LIKELY BE SEVERE ONCE
INITIATION OCCURS. THUS...THIS REGION WILL CONTINUE TO BE MONITORED
FOR GREATER REFLECTIVITY DEVELOPMENT AND THE NEED FOR A SEVERE
WEATHER WATCH THIS EVENING.
...ANALYSIS AND THREATS...
EARLY EVENING SURFACE ANALYSIS SHOWED AN AREA OF LOW PRESSURE
LOCATED OVER SOUTH CENTRAL OK /INVOF ADM/ WITH A DRY LINE TRAILING
SWWD /TO THE NW-W OF DALLAS-FT WORTH METROPLEX/ THROUGH SRN MONTAGUE
TO STEPHENS COUNTIES TX. MEANWHILE...A QUASI-STATIONARY BOUNDARY
EXTENDED ESEWD FROM THE SURFACE LOW THROUGH EXTREME SERN OK TO FAR
SRN AR AND WEST CENTRAL MS. LATEST VISIBLE SATELLITE IMAGERY AND
REGIONAL RADARS INDICATED MORE PERSISTENT AND LIKELY DEEPER CU/TCU
ALONG THE DRY LINE FROM WISE AND MONTAGUE COUNTIES TX TO LOVE COUNTY
OK...WITH A SECOND AREA OF GREATER CU FORMATION ALONG AND NORTH OF
THE STATIONARY FRONT...JUST EAST OF THE SURFACE LOW.
00Z FWD SOUNDING SHOWED A WEAK CAP REMAINS AROUND 700-800 MB WITH
MLCAPE CLOSE TO 1000 J/KG. THIS INSTABILITY WHICH WAS SIMILAR
WITHIN THE WARM SECTOR ACROSS NCNTRL/NERN TX INTO NWRN LA COMBINED
WITH EFFECTIVE BULK SHEAR AROUND 50 KT IS SUFFICIENT FOR ORGANIZED
STORMS. A STRAIGHT HODOGRAPH WITH THIS SOUNDING SUPPORTS SPLITTING
STORMS. GIVEN THE FAIRLY SUBSTANTIAL DRY SUB-CLOUD LAYER...STRONG
WIND GUSTS AND HAIL WOULD BE THE INITIAL PRIMARY THREATS.
HOWEVER...ANY STORM THAT CAN TRACK ALONG THE STATIONARY FRONT WOULD
HAVE A GREATER POTENTIAL TO PRODUCE A TORNADO.
...STORM INITIATION POTENTIAL...
GIVEN THE WEAK CAP YET EVIDENT ON THE 00Z FWD SOUNDING AND OVERALL
WEAK UPPER FORCING ACROSS THIS REGION...STORM INITIATION IS
UNCERTAIN DURING THE NEXT 1-2 HOURS...WHICH IS MORE CONSISTENT WITH
THE RECENT RUNS OF THE EXPERIMENTAL HRRR MODEL. TRENDS IN LOW LEVEL
FLOW STREAMLINE ANALYSIS INDICATED DIFFLUENT FLOW ACROSS THE
DISCUSSION AREA WITH WINDS OVER NWRN TX BEGINNING TO BACK IN
RESPONSE TO PRESSURE FALLS WITH THE LEE TROUGH OVER THE CENTRAL/SRN
HIGH PLAINS AND MORE VEERED SSWLY WINDS ALONG THE SABINE RIVER.
THIS WOULD TEND TO LIMIT LOW LEVEL CONVERGENCE ALONG AFOREMENTIONED
BOUNDARIES.
THUS...DESPITE THE MORE PERSISTENT CU/TCU DEVELOPMENT...STORM
INITIATION MAY NOT OCCUR UNTIL AFTER SUNSET ALONG THE RED RIVER
VALLEY OF NERN TX/SERN OK WHEN THE STRENGTHENING LLJ INTO THIS
REGION RESULTS IN AN INCREASE OF WAA/ASCENT AND MOISTENING. THESE
LATTER FACTORS WOULD SUPPORT BOTH A TORNADO THREAT AND HAIL/DAMAGING
WINDS.
..PETERS.. 03/26/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LZK...SHV...TSA...FWD...OUN...
LAT...LON 33009843 33579774 34149706 34689671 34719614 34409434
33909252 33119219 32459262 32319420 32689739 33009843
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