east GA Glascock, Warren and Jefferson Counties hit hard this morning with stationary heavy rain on sw side of Andrea. More 2 come #gawx
Severe weather steals the show today, and will do so again early Friday in the Southeast, especially around western Tenn Valley initially Friday. Today’s front will stall near Atlanta and then return quickly northward, ushering in higher dewpoints and muggy air for March on Friday. Showers and storms will fire up along this boundary and could turn severe.
One interesting aspect of the alignment is the positive tilt of the front. For a while now GFS has shown this incoming trough to become a strong positive tilt trough as new energy and backing flow holds the front back. Usually this is a heavy rain maker with repeating rain fall (training). The GFS shows this right now in part of the Southeast near the Appalachians and eventually slowly sliding into the Piedmont, beginning late Friday and lasting through Saturday. Sometimes convection robs the Carolina Piedmont of heavy rain, but this particular situation actually favors heavy rain since the tilt of the trough is very positive and slow, due to additional incoming 5h energy…so that’s something to keep in mind Saturday. Could be a large region receives several inches of rainfall from Birmingham northeastward to Raleigh, but I’ll fine tune it later. It appears hard hit drought regions of central GA to much of central SC and NC will benefit greatly from a decent rain event.
Most models still have the “Clipper” coming into the Kentucky/Ohio area later Sunday and crossing the Apps by early Monday, possibly developing a small weak system offshore NC or VA. We haven’t seen many clippers at all this Winter, but the GFS has had this several runs in a row, and ECMWF has shown some development as well, but is nowhere near developed as it once was. Looks like a stripe of very light snow from the Midwest, southeastward to the Tn/NC mountains, possibly much of Virginia and northern NC, as well as some for eastern NC/VA/lower MD before the sytem pulls out Monday. Nothing major, but a few mountain peaks in northern NC/ne TN and northward through VA and West VA mountains could pick up accumulation and at some point we’ll see if the models hold sway with a dusting for any other areas. Time of arrival could mean some areas are rain or sleet, not snow, but right now it’s only a small feature and only worth mentioning since any snow at all has been rare this Winter. Still, it will be turning colder and Windy Sunday and Monday. Briefly. We quickly go back to above normal temps.
URGENT – IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 46
NWS STORM PREDICTION CENTER NORMAN OK
440 AM CST WED FEB 29 2012
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
CENTRAL AND EASTERN KENTUCKY
NORTHERN MIDDLE TENNESSEE
EFFECTIVE THIS WEDNESDAY MORNING FROM 440 AM UNTIL NOON CST.
TORNADOES…HAIL TO 1.5 INCHES IN DIAMETER…THUNDERSTORM WIND
GUSTS TO 75 MPH…AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 90 STATUTE
MILES EAST AND WEST OF A LINE FROM 55 MILES NORTH NORTHEAST OF
LOUISVILLE KENTUCKY TO 55 MILES SOUTH OF BOWLING GREEN KENTUCKY.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU6).
REMEMBER…A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.
OTHER WATCH INFORMATION…CONTINUE…WW 43…WW 44…WW 45…
DISCUSSION…SRN IL/FAR SE MO SQLN WITH EMBEDDED…LONG-LIVED
SUPERCELLS EXPECTED TO CONTINUE E AT 50 KTS. SUBSTANTIAL LOW LVL
AIR MASS RECOVERY WILL PERSIST AHEAD OF SQLN ACROSS CNTRL KY…WITH
SFC DEWPOINTS IN THE UPR 50S TO LOW 60S F EXPECTED OVER WW AREA BY
12-15Z. LARGE SCALE FORCING FOR ASCENT WILL BE WEAK. BUT PRESENCE
OF EXISTING LONG-LIVED STORMS…STRENGTH OF WIND FIELD…AND
POTENTIAL FOR ISOLD WAA STORMS TO BECOME ROOTED IN THE BOUNDARY
LAYER AHEAD OF SQLN SUGGEST THE POSSIBILITY FOR TORNADOES IN
ADDITION TO LOCALLY DMGG WIND.
AVIATION…TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 65 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
450. MEAN STORM MOTION VECTOR 26050.
First Major Apps/Va Snowstorm
Lots to talk about with this one. I didn’t change my snowfall prog map from a couple days ago..didn’t really need to , except to fine tune it. It’s nice to see models come around to synoptics By early Sunday, the surface low will be in west central Alabama, with comma head/deformation axis snow developing in western Kentucky, northest Tennessee and northeast Arkansas. The models don’t respond with surface cold there, but I wouldn’t be surprised to see some accumulations early Sunday in the western Tenn. Valley. Meanwhile, the cold is working down the eastern side of the mountain chain and rain will switch over to sleet then snow quickly in western Virginia down to near Boone, NC. An 850 low will develop in northern Alabama and be slow to move due east. The confluent zone in New England should keep all the moisture from roughly DC, south and westward, as has been shown several days now. Again, synoptics rule! This is a type of storm where the moisture axis will pivot, and eventually stretch west to east, so there will be a dryslot developing just east of the surface low, this appears to be around southern NC and all of SC, GA by midday or afternoon Sunday. But there is a strong 5H system , which is the golden nugget and usually not existent in most storms, which will help keep 700mb moisture spawning from thin air, in northern half of NC and Tennessee late day, and this slug of moisture will “roll” or wobble across the Appalachians during Sunday into Sunday night, finally exiting the Carolina Coast by early Monday.
18z GFS still has a pretty stormy look to it for the Apps and west especially. Folks in the Tennessee valley may be wishing the rain to be gone a while after this week, but the pattern continues to support system developing in the Southern Plains and pulling northeast toward the Lakes.
The Friday system will come on the heels of the midweek system, quickly overspreading Arkansas, Tennessee and Kentucky, and will place the entire Southeast in the warm sector by Friday night and Saturday. We’ll have to watch how unstable it becomes in western Tn/Ky/Ark/north MS/Al especially closer to the dynamics.