SWODY1
SPC AC 151246
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0746 AM CDT THU APR 15 2010
VALID 151300Z - 161200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
THE MAIN BELT OF THE WLYS WILL REMAIN LARGELY N OF THE CONUS THIS
PERIOD...LEAVING MUCH OF THE NATION IN RELATIVELY SLACK FLOW. AN
EXCEPTION WILL BE THE UPR MS VLY AND UPR GRT LKS...WHERE MODERATE
WSW FLOW WILL PREVAIL ON SRN SIDE OF UPR LOW MOVING E INTO ONTARIO.
FARTHER S...WEAK VORT NOW OVER FAR W TX SHOULD DRIFT SLOWLY E
THROUGH FRI.
AT THE SFC...COLD FRONT ASSOCIATED WITH ONTARIO UPR SYSTEM WILL MOVE
STEADILY E/SE ACROSS MN/WI/IA/NRN IL AND MI...WHILE TRAILING WRN
PART RESUMES A SLOWER SWD PUSH ACROSS THE CNTRL PLNS. WARM FRONT
NOW DEVELOPING OVER ERN MI SHOULD BECOME BETTER DEFINED AND EXTEND
FROM DE INTO ERN PA AND NY BY 12Z FRI.
...UPR MS VLY/UPR GRT LKS...
FILTERED SUNSHINE SHOULD ALLOW MODEST DESTABILIZATION OF PRE-
FRONTAL AIR OVER THE UPR MS VLY/UPR GRT LKS TODAY...WHERE PW WILL
INCREASE TO AROUND 1 INCH AND AVERAGE SFC DEWPOINTS WILL RANGE FROM
THE UPR 40S TO THE LWR 50S F. MID LVL LAPSE RATES WILL NOT BE VERY
STEEP...THUS SBCAPE SHOULD REMAIN AOB 500 J/KG. THE FRONTAL ZONE
WILL...HOWEVER...BE GLANCED BY ASCENT ASSOCIATED WITH VORT LOBE
CROSSING THE DAKOTAS.
BY EARLY AFTN...DIURNAL DESTABILIZATION OF EXISTING CONFLUENCE AXIS
NOW EXTENDING FROM NE NEB TO UPR MI SHOULD SUPPORT MODEST
STRENGTHENING /AND POSSIBLY AN INCREASE IN COVERAGE/ OF TSTMS NOW
PRESENT ALONG THIS CORRIDOR. AMPLE /40+ KT/ DEEP WLY SHEAR WILL
EXIST IN THE REGION FOR POTENTIAL SUPERCELLS/SUSTAINED STORMS. BUT
WEAK BUOYANCY SHOULD PRECLUDE DEVELOPMENT OF AN APPRECIABLE THREAT
FOR SVR WIND AND HAIL.
...CNTRL PLNS...
FARTHER S...LOW-MID 50S SFC DEWPOINTS WILL PERSIST AHEAD OF
AFOREMENTIONED FRONT FROM SRN NEB INTO KS/ERN CO...BENEATH SOMEWHAT
STEEPER MID-LVL LAPSE RATES THAN THOSE EXPECTED OVER THE UPR MS VLY.
WITH HEATING...THIS SHOULD YIELD SBCAPE OF 500-1000 J/KG BY AFTN.
UPR LVL FORCING FOR ASCENT WILL BE NEGLIGIBLE... AND WIND PROFILES
WEAK. BUT CONVERGENCE ALONG FRONT...AND LIGHT POST-FRONTAL UPSLOPE
FLOW...MAY SUPPORT SLOWLY-MOVING/REGENERATIVE CLUSTERS OF MULTICELL
STORMS. THESE MAY POSE A THREAT FOR ISOLD SVR WIND/HAIL INTO
TONIGHT.
...S TX...
INCREASINGLY MOIST /PW AOA 1.5 INCHES/ 2-3 KM DEEP ESELY FLOW WILL
CONTINUE ACROSS THE LWR RIO GRANDE VLY OF S TX THROUGH THIS
EVE...AHEAD OF SLOWLY-MOVING W TX UPR VORT. PERSISTENT
REDEVELOPMENT OF DEEP CONVECTION WITHIN THIS REGIME ALREADY HAS
RESULTED IN THE DEVELOPMENT OF A LOOSELY-ORGANIZED MCV-TYPE
CIRCULATION NEAR DRT. WITH MOIST UPSLOPE CONTINUING...DAYTIME
DESTABILIZATION MAY BE SUFFICIENT FOR SOME INCREASE IN UPDRAFT
STRENGTH/CELL LONGEVITY ALONG NRN AND ERN FRINGE OF THE MCV. GIVEN
CONSIDERABLE DEGREE OF LOW-LVL VEERING LIKELY TO PERSIST OVER
REGION...POTENTIAL WILL EXIST FOR ISOLD STORMS TO BRIEFLY ASSUME
LOW-LVL CIRCULATIONS. THESE COULD POSE A LOW PROBABILISTIC THREAT
FOR A TORNADO.
..CORFIDI/JIRAK/GRAMS.. 04/15/2010
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