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 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