SPC 1200Z Day 1 Outlook
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1259 AM CDT MON APR 30 2012 VALID 301200Z - 011200Z ...THERE IS A SLGT RISK OF SVR TSTMS FROM NWRN TX INTO SRN KS AND OK... ...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN MO AND SRN IL EWD INTO WRN PA... ...SYNOPSIS... AN RELATIVELY ZONAL FLOW REGIME WILL EXIST ACROSS THE CONUS WITH A LEAD SHORTWAVE TROUGH MOVING FROM THE MID MS VALLEY NEWD ACROSS THE OH VALLEY DURING THE DAY. THIS WAVE WILL COMBINE WITH A WEAK SURFACE TROUGH AND INSTABILITY FOR A FEW SEVERE STORMS DURING THE DAY. AMPLE LOW LEVEL MOISTURE WILL EXIST WWD ACROSS THE MS VALLEY AND SRN PLAINS STATES...WITH MID 60S F OVER TX AND OK. HERE...NUMEROUS ROUNDS OF THUNDERSTORMS ARE EXPECTED...THE STRONGEST OF WHICH WILL OCCUR LATER IN THE DAY WHEN A LOW AMPLITUDE UPPER FEATURE MOVES EWD OUT OF CO AND NM...HELPING TO FOCUS SEVERE STORMS OVER MUCH OF THE TX PANHANDLE...SWRN KS...AND WRN OK. OTHER EARLY ACTIVITY WILL TRANSITION FROM SERN KS/OK INTO MO AND IL WITH HEAVY RAIN AND SOME SEVERE. ...SRN PLAINS... SCATTERED STORMS WILL BE ONGOING ACROSS THE REGION...MOST LIKELY FROM OVER SERN KS...NERN OK AND INTO SRN MO ALONG A QUASI-STATIONARY BOUNDARY. SOME OF THIS ACTIVITY COULD HAVE A MARGINAL HAIL AND WIND THREAT...AND OUTFLOW FROM THESE STORMS MAY HAVE AN IMPACT ON FURTHER DEVELOPMENT OVER OK. SEVERAL HIGH RESOLUTION MODELS DEPICT ISOLATED ACTIVITY DEVELOPING BY MID AFTERNOON OVER WRN OK...AND LARGE HAIL WOULD BE LIKELY. MODESTLY VEERING LOW LEVEL WIND PROFILES AND HIGH RH BOUNDARY LAYER SUGGEST AN ISOLATED TORNADO MAY OCCUR AS WELL. FARTHER W...STRONG HEATING WILL OCCUR NEAR THE DRYLINE...AND CIN WILL EASILY BE ERODED BY MID AFTERNOON. A BROKEN LINE OF SUPERCELLS IS EXPECTED TO FORM OVER THE TX PANHANDLE AND S PLAINS...EVOLVING EWD WITH A CONTINUED WIND AND HAIL THREAT THROUGH EVENING. SOME HAIL WILL BE VERY LARGE. LOCALLY SIGNIFICANT WIND GUSTS MAY OCCUR WITH THE LARGEST SUPERCELLS. THE GREATEST CONCENTRATION OF SEVERE IS EXPECTED TO BE OVER THE TX PANHANDLE INTO SWRN OK. ...OH VALLEY REGION... A WEAK SURFACE TROUGH WILL BE ENOUGH TO FORCE SCATTERED STORMS BY AFTERNOON WITH STRONG HEATING. 50-60 KT MIDLEVEL FLOW WILL HELP ORGANIZE STORMS INTO CELLS AND/OR BOWS...CAPABLE OF LARGE HAIL AND DAMAGING WINDS. THE THREAT MAY EXTEND AS FAR E AS WRN PA BUT WILL END ABRUPTLY AS STORMS BECOME ELEVATED POINTS E. ...WRN VA AND NC... A PLUME OF 60S DEWPOINTS OFF THE ATLANTIC AND DAYTIME HEATING SHOULD RESULT IN ISOLATED THUNDERSTORMS FAVORING THE HIGHER TERRAIN OF SWRN VA AND WRN NC. WITH VEERING WINDS WITH HEIGHT AND RELATIVELY COOL PROFILES ALOFT...LARGE HAIL WILL BE LIKELY...ALONG WITH LOCALLY STRONG GUSTY WINDS. THIS ACTIVITY SHOULD WANE BY EVENING. ..JEWELL/GARNER.. 04/30/2012
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day1otlk_1200.html
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