SWODY1
SPC AC 160058
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0758 PM CDT THU APR 15 2010
VALID 160100Z - 161200Z
...NO SVR TSTM AREAS FORECAST...
...SWRN THROUGH S CNTRL TX...
CONVECTION WILL PERSIST WITHIN ZONE OF DEEP ASCENT AND SUBTROPICAL
MOISTURE EAST OF NEARLY STATIONARY VORT MAX SITUATED OVER WRN TX. A
30-35 KT LOW LEVEL JET WILL REMAIN ACROSS S CNTRL TX OVERNIGHT.
HOWEVER...VWP AND FORECAST SOUNDINGS SHOW ONLY A GRADUAL VEERING
FROM 0-3 KM WITH 0-1 KM STORM RELATIVE HELICITY GENERALLY AOB 100
M2/S2. WHILE SOME BRIEF...WEAK LOW LEVEL ROTATION REMAINS POSSIBLE
WITH SOME OF THE CONVECTION DEVELOPING IN THIS ZONE...TORNADO THREAT
APPEARS LIMITED.
...GREAT LAKES AND UPPER MS VALLEY THROUGH OH VALLEY...
AS UPPER LOW CONTINUES THROUGH SRN ONTARIO...NRN PORTION OF COLD
FRONT THAT EXTENDS FROM NRN WI SWWD THROUGH NRN IA AND THE CNTRL
PLAINS WILL MOVE SEWD THROUGH THE GREAT LAKES AND APPROACH THE OH
VALLEY TOWARD THE END OF THE PERIOD.
THE 00Z RAOB FROM GRB WI CONFIRMS THE OBJECTIVE ANALYSIS INDICATING
VERY LIMITED INSTABILITY WITH MLCAPE BELOW 200 J/KG. CONVECTION WILL
LIKELY CONTINUE INTO THE OVERNIGHT WITHIN ZONE OF MODEST FORCING
ALONG AND JUST AHEAD OF THE FRONT...GRADUALLY SHIFTING SEWD TOWARD
THE OH VALLEY. STRONGER VERTICAL SHEAR WILL REMAIN POST
FRONTAL...BUT GRB RAOB DATA INDICATE 40-50 KT FLOW IN THE 1-6 KM
LAYER ALONG WITH A RELATIVELY DRY BOUNDARY LAYER /20F
TEMPERATURE-DEWPOINTS SPREADS/. WHILE AN ISOLATED STRONG WIND GUST
OR TWO CANNOT BE RULED OUT...MAINLY BEFORE DECOUPLING OF THE
BOUNDARY LAYER THIS EVENING...THE VERY WEAK INSTABILITY REMAINS A
LIMITING FACTOR.
...ERN CO THROUGH KS...
THUNDERSTORMS ARE DEVELOPING IN THE POST-FRONTAL UPSLOPE REGIME OF
SERN CO AS WELL AS FARTHER EAST IN VICINITY OF SWD ADVANCING COLD
FRONT ACROSS NRN KS AND SERN NEB. FLOW ALOFT AND VERTICAL SHEAR IS
WEAK AND SUPPORTIVE OF MULTICELLS. BOUNDARY LAYER
TEMPERATURE-DEWPOINTS SPREADS AROUND 20F AND 500-1000 J/KG MLCAPE
WILL SUPPORT A LOW END THREAT OF MAINLY ISOLATED STRONG WIND GUSTS
UNTIL MID EVENING. HOWEVER...THE MARGINAL SEVERE THREAT SHOULD
GRADUALLY DIMINISH WITH THE ONSET OF NOCTURNAL COOLING.
..DIAL.. 04/16/2010
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