SWODY1
SPC AC 201627
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1027 AM CST MON FEB 20 2012
VALID 201630Z - 211200Z
...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING
ACROSS PARTS OF CNTRL AND ERN KS/OK...
...SYNOPSIS...
POTENT SHORT-WAVE TROUGH AND ASSOCIATED 80-100 KT MIDLEVEL JET
STREAK WILL TRANSLATE EWD ACROSS THE CNTRL/SRN PLAINS INTO MID-MS
VALLEY WITH SYSTEM ASSUMING AN INCREASING NEGATIVE TILT WITH TIME.
IN THE LOW LEVELS...ATTENDANT SURFACE CYCLONE WILL DEVELOP ACROSS
NRN PARTS OF KS/MO. A PRE-FRONTAL TROUGH/WEAK DRYLINE WILL ADVANCE
EWD TOWARD THE I-35 CORRIDOR OF KS/OK BY 21/00Z...LIKELY SERVING AS
THE FOCUS FOR STRONG-SEVERE TSTM DEVELOPMENT LATER THIS AFTERNOON
INTO EVENING. THIS FEATURE WILL EVENTUALLY BE OVERTAKEN BY A COLD
FRONT PROGRESSING EWD/SEWD THROUGH THE CNTRL/SRN PLAINS.
...KS/OK...
12Z OBSERVED SOUNDINGS AND SATELLITE-DERIVED PW IMAGERY SHOW LIMITED
MOISTURE WITHIN DEVELOPING WARM SECTOR OF EXTRATROPICAL CYCLONE WITH
BOUNDARY LAYER DEWPOINTS IN THE 40S AND PW VALUES OF .5-.7 INCH.
HOWEVER...SIGNIFICANT MIDLEVEL COOLING IS FORECAST TO OVERSPREAD
REGION TODAY WITH 500-MB TEMPERATURES OF -22 TO -28 C EXPECTED OVER
CNTRL PARTS OF KS/OK BY 21/00Z. WHEN COUPLED WITH A NARROW AXIS OF
STRONGER DIABATIC WARMING IN THE BOUNDARY LAYER ALONG DRYLINE /ON
THE IMMEDIATE BACK EDGE OF CIRRUS SHIELD/...A CONSENSUS OF MODEL
SOUNDINGS SUGGEST SBCAPE VALUES INCREASING TO 200-600 J/KG.
LATEST CONVECTION-ALLOWING AND MESOSCALE MODEL GUIDANCE REMAINS IN
GOOD AGREEMENT IN SUGGESTING THAT A BELT OF FOCUSED DCVA WILL GIVE
RISE TO WIDELY SCATTERED TSTMS BY 20/21-23Z FROM NEAR THE COLD
FRONT/DRYLINE OCCLUSION OVER CNTRL KS SWD ALONG THE DRYLINE INTO
CNTRL OK. THE AMBIENT KINEMATIC ENVIRONMENT WILL FEATURE 40-45 KT
OF EFFECTIVE BULK SHEAR AND EFFECTIVE SRH VALUES OF 100-250 M2/S2.
GIVEN THAT SUFFICIENT BUOYANCY CAN DEVELOP ALONG THE DRYLINE...THE
SETUP WILL FAVOR LOW-TOPPED SUPERCELLS CAPABLE OF MARGINALLY SEVERE
HAIL...LOCALLY STRONG WIND GUSTS AND PERHAPS A COUPLE OF BRIEF
TORNADOES THROUGH THIS EVENING.
..MEAD/HURLBUT.. 02/20/2012
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