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

Severe Thunderstorm and Flash Flood Threat in the East; Snow in the Rockies;

The storm system producing severe weather and isolated flash flooding will begin to weaken tonight. As the storm moves east, several chances for severe weather and heavy rain are possible from the Midwest and Ohio Valley to the Southern Plains, Lower Mississippi and Tennessee valley. Heavy snow continue to impact the Northern Rockies. Critical fire weather conditions persist in the Southern Plains Read More >

SPC AC 250730 DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0230 AM CDT MON APR 25 2011 VALID 271200Z - 281200Z ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF CENTRAL AND EASTERN KENTUCKY...MIDDLE AND EASTERN TENNESSEE...NORTHEAST MISSISSIPPI...CENTRAL AND NORTHERN ALABAMA...AND NORTHWEST GEORGIA... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PORTION OF THE ERN U.S. FROM THE LOWER AND MID MS/OH VALLEYS EWD... ...SYNOPSIS... A LARGE UPPER TROUGH WILL CONTINUE SHIFTING EWD ACROSS THE U.S. THIS PERIOD...WITH A POTENT SHORT-WAVE TROUGH/SPEED MAX SHIFTING EWD INTO THE MID SOUTH REGION INTO THE AFTERNOON. AS THIS OCCURS...SECONDARY SURFACE LOW DEVELOPMENT IS EXPECTED ALONG THE COLD FRONT S OF THE MAIN GREAT LAKES REGION LOW. THIS SYNOPTIC-SCALE SETUP FAVORS SIGNIFICANT SEVERE WEATHER POTENTIAL E OF THE MS VALLEY. ...PA/NW SSWWD TO THE GULF COAST... YET ANOTHER DAY OF POTENTIALLY VERY SIGNIFICANT SEVERE WEATHER IS EXPECTED DAY 3 /WED. AND EARLY THU. APR. 27 AND 28/ -- WITH ELEVATED THREAT FOR A TORNADO OUTBREAK EVIDENT ACROSS THE MID SOUTH AND INTO PORTIONS OF THE CENTRAL GULF COAST STATES. STRONG/SEVERE STORMS SHOULD BE ONGOING AT THE START OF THE PERIOD ACROSS THE NWRN PORTIONS OF THE SLIGHT RISK AREA...AS THE POTENT SHORT-WAVE TROUGH AND ASSOCIATED MID-/UPPER-LEVEL SPEED MAX ROUNDS THE BASE OF THE LARGER-SCALE TROUGH. WHILE AN INITIAL SURFACE LOW SHOULD SHIFT NNEWD ACROSS THE OH VALLEY/MIDWEST...SECONDARY SURFACE LOW DEVELOPMENT IS FORECAST DURING THE AFTERNOON IN THE KY/TN VICINITY...WITH LOCALLY-BACKED SURFACE FLOW VEERING/INCREASING SUBSTANTIALLY WITH HEIGHT RESULTING IN SHEAR PROFILES VERY SUPPORTIVE OF SUPERCELLS AND TORNADOES. THE MOST FAVORABLE COMBINATION OF RICH LOW-LEVEL MOISTURE...STRONG SHEAR...FOCUSED LARGE-SCALE ASCENT...AND ANTICIPATED LACK OF APPRECIABLE PRIOR CONVECTION INDICATES A RELATIVELY HIGH-CONFIDENCE AREA OF CONCENTRATED SIGNIFICANT THREAT FOR POTENTIALLY STRONG TORNADOES AND WIDESPREAD WIND DAMAGE CENTERED OVER THE MID SOUTH/TN VALLEY REGION. THEREFORE...WILL INTRODUCE MODERATE RISK FORECAST ATTM -- INDICATIVE OF OUTBREAK POTENTIAL. ALONG WITH FAIRLY SUBSTANTIAL SEVERE POTENTIAL EXTENDING FARTHER NNEWD INTO PA/NY -- INCLUDING THREATS FOR DAMAGING WINDS AND ISOLATED TORNADOES...SEVERE STORMS WILL LIKELY ALSO EXTEND E OF THE APPALACHIANS INTO THE ATLANTIC COAST STATES. ALONG WITH THE LIKELIHOOD FOR AFTERNOON SEVERE CONVECTION...SEVERE CONVECTION MAY CONTINUE INTO THE OVERNIGHT HOURS AS THE SURFACE FRONT CRESTS THE APPALACHIANS. ..GOSS.. 04/25/2011