Epic Outbreak of Tornadoes Across the Southeast on 27-28 April 2011 Impacts Northeast Georgia and Western North Carolina

Snow Across the Great Lakes, Central Appalachians, and Northeast; Unsettled Weather in the West

Light to moderate snow will continue into Saturday over the Great Lakes, Central Appalachians, and Northeast. This weekend into next week, a series of atmospheric rivers will bring gusty winds, periods of heavy rain, and mountain snow to northern California and the Pacific Northwest. Colder temperatures are in store for the weekend from the Great Lakes to East Coast. Read More >

SPC AC 280050 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0750 PM CDT WED APR 27 2011 VALID 280100Z - 281200Z ...THERE IS A HIGH RISK OF SVR TSTMS OVER ECNTRL/NERN AL...SERN TN AND NWRN GA... ...THERE IS A MDT RISK OF SVR TSTMS FROM ERN KY SWD INTO CNTRL AL... ...THERE IS A SLGT RISK OF SVR TSTMS OVER MUCH OF THE ERN U.S. ASIDE FROM NEW ENGLAND AND PENINSULAR FL... ...A HISTORICAL AND DANGEROUS OUTBREAK OF SEVERE THUNDERSTORM AND TORNADOES CONTINUES ACROSS PARTS OF THE TN VALLEY AND SRN STATES... CHANGES TO PREVIOUS OUTLOOK INCLUDE: 1/ EXTEND HIGH RISK TO INCLUDE MORE OF NWRN GA 2/ ADD HIGHER TORNADO PROBABILITIES IN MID-ATLANTIC 3/ REDUCE MDT RISK SWD FROM THE OH VLY 4/ TRIM WRN EDGE OF SVR RISKS IN TANDEM WITH FROPA 1. SVRL TORNADIC SUPERCELLS CONTINUE ENE FROM ECNTRL MS AND CNTRL AL INTO ERN TN AT MID-EVENING. FAVORED ZONE OF ADDITIONAL SUPERCELL DEVELOPMENT MAY OCCUR ALONG LOW-LEVEL CONFLUENCE ACROSS SWRN-CNTRL AL THROUGH LATE EVENING. THIS WILL BE AMID THE MOST VOLATILE COMBINATION OF EFFECTIVE SRH AND INSTABILITY AND THERE WILL BE A DANGEROUS STRONG-VIOLENT TORNADO RISK SPREADING ENE THROUGH CNTRL/NERN AL INTO NWRN AL AND SERN TN THROUGH THE EVENING HOURS. AS A RESULT...THE HIGH RISK HAS BEEN EXPANDED EWD TO INCLUDE METRO ATLANTA. PLEASE REFER TO LATEST MESOSCALE DISCUSSIONS /SWOMCD/ AND WATCHES FOR UP-TO-THE-MINUTE METEOROLOGICAL DETAILS. 2. A LEAD MID-LEVEL WAVE CONTINUES TO MOVE NEWD INTO THE MID-ATLANTIC REGION. INCREASING ASCENT...LOW-LEVEL CONFLUENCE ALONG THE FOOTHILLS...MLCAPE TO 1500 J PER KG AND 300+ 0-1KM SRH GAVE RISE TO SUPERCELLS WITH ISOLD TORNADOES EARLY THIS EVENING. THERE WILL BE A RISK OF BRIEF TORNADOES THROUGH MID-EVENING...ESPECIALLY FROM CNTRL/NRN VA THROUGH DISTRICT OF COLUMBIA INTO CNTRL MD. OTHERWISE...DMGG WIND GUSTS AND LARGE HAIL WILL BE LIKELY...BEFORE STORMS WEAKEN WITH LOSS OF INSOLATION. 3. ALTHOUGH THERE WILL STILL BE A THREAT FOR ISOLD TORNADOES...DMGG WINDS AND HAIL FROM THE OH RVR NWD TOWARD THE LOWER GREAT LAKES INTO LATE EVENING...HIGHEST PROBABILITIES OF SUSTAINED SVR WEATHER WILL REMAIN FROM KY COALFIELDS SWD. CONSIDERABLE CLOUDS AND RAIN HAVE MITIGATED STRONG DESTABILIZATION TODAY PER 00Z ILN SOUNDING. THEREFORE...MDT RISK/PROBABILITIES HAVE BEEN SHIFTED SWD. ..RACY.. 04/28/2011 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z