SPC MD 726

MD 0726 CONCERNING SEVERE POTENTIAL…TORNADO WATCH LIKELY FOR MUCH OF OK INTO NWRN TX AND SERN KS


MESOSCALE DISCUSSION 0726
NWS STORM PREDICTION CENTER NORMAN OK
1226 PM CDT MON MAY 20 2013

AREAS AFFECTED...MUCH OF OK INTO NWRN TX AND SERN KS

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 201726Z - 201930Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...SEVERE STORMS ARE LIKELY TO FORM THIS AFTERNOON WITH A FEW
SIGNIFICANT TORNADOES...EXTREMELY LARGE HAIL...AND DAMAGING WINDS
ALL POSSIBLE. TWO WATCHES WILL BE NEEDED SOON FROM KS INTO N TX.

DISCUSSION...SURFACE MAP SHOWS A QUASI-STATIONARY BOUNDARY FROM SERN
KS INTO NRN OK AND BENDING SWWD W OF THE I-44 CORRIDOR. FARTHER
SW...A WEAK AREA OF LOW PRESSURE WAS NOTED OVER NWRN TX...ON THE
NOSE OF A LOW LEVEL LAPSE RATE PLUME WITH DRYLINE EXTENDING SW
ACROSS W TX.

VISIBLE IMAGERY SHOWS DEEPENING CU ALONG THE BOUNDARY FROM NRN OK
INTO SERN KS WHERE A DEEP MOIST LAYER EXISTS. GIVEN A GRADUAL
INCREASE IN THETA-E AND BREAKS IN THE CLOUDS...THIS AREA COULD BE
WHERE INITIAL DEVELOPMENT OCCURS. LONG HODOGRAPHS AND STEEP MIDLEVEL
LAPSE RATES WILL FAVOR VERY LARGE HAIL...AND LOW LEVEL VEERING WIND
PROFILES WILL BE SUFFICIENT FOR TORNADOES GIVEN AFOREMENTIONED
THERMODYNAMIC FACTORS.

TO THE S...AN EXTREMELY VOLATILE AIR MASS EXISTS WITH AN INCREASING
CU FIELD FROM NWRN TX INTO SWRN OK WHERE STRONG HEATING PERSISTS.
WIND FIELDS ALOFT ARE MORE THAN FAVORABLE FOR SUPERCELLS...WITH VERY
LARGE HAIL LIKELY. ALTHOUGH SHEAR IN THE LOWEST 1-2 KM IS NOT
PARTICULARLY STRONG...VERY LARGE VERTICAL ACCELERATIONS...AS WELL AS
HODOGRAPH AUGMENTATION NEAR THE SFC FRONT WILL AID IN TORNADO
POTENTIAL. HP SUPERCELLS ARE EXPECTED WITH STRONG MESOCYCLONES AND
POSSIBLE RAIN-WRAPPED TORNADOES.

ACTIVITY MAY EVENTUALLY MERGE INTO ONE OR MORE BOWS...AND RAPIDLY
EXPAND NEWD ACROSS ERN OK LATER THIS EVENING PER MULTIPLE CONVECTION
ALLOWING MODELS.

..JEWELL/KERR.. 05/20/2013

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

ATTN...WFO...LSX...SGF...EAX...TSA...TOP...ICT...FWD...OUN...
SJT...

LAT...LON   38009568 38799359 38829292 38659248 38349229 37719234
            35899422 35449480 34559586 34049620 33559661 33369740
            33269840 33309891 33409912 33629915 33849905 34419848
            34689843 35099837 35689820 37169692 38009568

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md0726.html