The SPC is forecasting ...severe thunderstorms expected over parts of the central plains this afternoon and tonight.... Please read the latest public statement about this event.
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SPC AC 291955 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0255 PM CDT THU MAY 29 2008 VALID 292000Z - 301200Z ...THERE IS A HIGH RISK OF SVR TSTMS THIS AFTN AND TONIGHT ACROSS PARTS OF CNTRL/ERN NEBRASKA INTO PARTS OF WRN IA.... ...THERE IS A MDT RISK OF SVR TSTMS SURROUNDING THE HIGH RISK AREA...ACROSS PARTS OF WRN/NRN KS...MUCH OF CNTRL/ERN NEB...SERN SD...SRN MN...MUCH OF IA AND NW MO.... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA...FROM THE CNTRL PLAINS INTO THE UPPER MS VLY.... AN OUTBREAK OF SEVERE THUNDERSTORMS NOW APPEARS TO BE UNDERWAY ACROSS PARTS OF THE NORTH CENTRAL PLAINS INTO THE MID MISSOURI VALLEY. SUPERCELLS CAPABLE OF PRODUCING STRONG TORNADOES ARE POSSIBLE LATE THIS AFTERNOON...WITH A SEVERE MESOSCALE CONVECTIVE SYSTEM LIKELY TO EVOLVE BY THIS EVENING...CONTINUING INTO THE OVERNIGHT HOURS. ...CENTRAL HIGH PLAINS INTO UPPER MISSISSIPPI VALLEY... MODELS CONTINUE TO INDICATE THAT A DEEPER...BROADER SCALE MID-LEVEL SHORT WAVE TROUGH WILL EVOLVE LATER TODAY/TONIGHT ACROSS THE NORTHERN PLAINS/UPPER MISSISSIPPI VALLEY...AS A SERIES OF SMALLER SCALE IMPULSES CONTINUE TO EMERGE FROM THE DEAMPLIFYING SOUTHERN BRANCH TROUGH OVER THE EASTERN PACIFIC AND WESTERN STATES. ONE OF THESE IMPULSES ALREADY APPEARS TO BE LIFTING INTO THE CREST OF THE PLAINS SUBTROPICAL RIDGE...ACROSS THE DAKOTAS. ANOTHER...MORE SIGNIFICANT IMPULSE APPEARS TO BE JUST NOW BEGINNING TO SHIFT NORTHEAST OF THE WYOMING/COLORADO ROCKIES. THIS LATTER FEATURE IS PROGGED TO BE ACCOMPANIED BY MORE SUBSTANTIAL HEIGHT FALLS ACROSS THE NORTH CENTRAL PLAINS BETWEEN NOW AND EARLY EVENING. AND...THIS SHOULD EFFECTIVELY CONTRIBUTE TO THE ELIMINATION OF INHIBITION WHICH REMAINS CONSIDERABLE ON THE LEADING EDGE OF LOW-LEVEL MOISTURE RETURN. UPPER 60S SURFACE DEW POINTS HAVE REACHED CENTRAL NEBRASKA. AND...ELEVATED MOISTURE RETURN IN A LINGERING ZONE OF LOWER/MID TROPOSPHERIC WARM ADVECTION HAVE MAINTAINED CONSIDERABLE CONVECTIVE DEVELOPMENT ACROSS THE EASTERN DAKOTAS/SOUTHERN MINNESOTA INTO THE UPPER MISSISSIPPI VALLEY. THIS IS SLOWING DESTABILIZATION NORTH/EAST OF THE MISSOURI RIVER. BUT...FORCING ASSOCIATED WITH A CONSOLIDATING SURFACE FRONTAL WAVE IS EXPECTED TO CONTRIBUTE TO INCREASING INSTABILITY LATER THIS EVENING/ OVERNIGHT. THE INITIATION OF CONVECTIVE DEVELOPMENT IS ALREADY UNDERWAY ACROSS THE HIGH PLAINS...FROM EASTERN WYOMING INTO EASTERN NEW MEXICO. AND...HIGH BASED STORMS ARE EXPECTED TO GRADUALLY STRENGTHEN WHILE SPREADING EASTWARD LATE THIS AFTERNOON. INSTABILITY AND DEEP LAYER SHEAR...BENEATH A SEASONABLY STRONG MID/UPPER JET STREAK CURVING OUT OF THE SOUTHERN PLATEAU/CENTRAL ROCKIES THROUGH THE MID MISSOURI VALLEY...WILL BE SUFFICIENT FOR SUPERCELLS. ACTIVITY WILL EVENTUALLY ENCOUNTER BETTER LOW-LEVEL MOISTURE... ROUGHLY NORTH/EAST OF HILL CITY KS INTO NORTH CENTRAL NEBRASKA... WHERE FURTHER INTENSIFICATION WILL OCCUR...AND NEW STORMS WILL DEVELOP...WITH INCREASING TORNADIC POTENTIAL ALONG A 40-60 KT SOUTH SOUTHWESTERLY LOW-LEVEL JET AXIS BY/SHORTLY AFTER 30/00Z. WITHIN THE PRESENCE OF STRONG DEEP LAYER SHEAR....LARGE CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS...AND MIXED LAYER CAPE OF 2000-3000 J/KG...POTENTIAL EXISTS FOR A FEW STRONG TORNADOES IN LONG-LIVED SUPERCELLS. ALTHOUGH UPSCALE CONVECTIVE DEVELOPMENT INTO A SEVERE MESOSCALE CONVECTIVE SYSTEM IS STILL ANTICIPATED THIS EVENING...ISOLATED SUPERCELLS WITH TORNADOES MAY CONTINUE TO FORM AS INHIBITION WEAKENS DOWNSTREAM...ALONG A WEAK WARM FRONTAL ZONE ACROSS PARTS OF EASTERN NEBRASKA/SOUTHWEST IOWA. OTHERWISE...THE RISK FOR DAMAGING WINDS PROBABLY WILL BECOME THE MORE PROMINENT THREAT ACROSS EASTERN NEBRASKA INTO WESTERN IOWA...BEFORE STORMS BEGIN TO WEAKEN EAST OF THE MID MISSOURI VALLEY OVERNIGHT. ..KERR.. 05/29/2008 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z