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T.S. Lee


HWY316wx

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closer to the circulation and triple point there will be some threat. Thats for Ala, Miss. areas. Probably none around here. Unless the circulation survives well on its trip northeast, but eventually its progged to drift north and open up, west of the Apps.

Now, I would not be surprised to see the circulation move directly over the Apps instead of west Tennessee. This track looks really interesting for us.

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12z Euro has no real surprises on the evolution of the system. Its similar to GFS and has the closed 5h drifting into Miss. but the sfc center goes toward central Alabama. The heavy rains will first be on the nw side and quickly reach eastward to nw GA and its at that time that the best lift is ongoing sometime Monday and early Tuesday, when nearly 5 to 7" of rain falls over a huge area. Obviously going to be flooding issues stretching from central MS across much of north half Alabama into southern TN and nw GA, but both models quickly drop the damming front into the east side of the Apps (Carolinas). In fact, a pretty strong warm season damming event with a 1024 high wedging down, but aloft we have strong south 850 winds, and surface southeast winds, converging with NE winds coming into VA and NC during the day, setting up strong convergence for the foothills and Upstate SC region. Models place 3" even well out into the Piedmont, and increasing rapidly from there as you go west to the mountains, up to 5 to 7".

Even though the dryslot kicks in at 7H, the strong upslope component and 850 moisture will ring out showers nearly continuously on the se slopes in the usual wet areas south and west of Asheville. This is when the radar shows echoes developing out of nothing along the escarpment (true upslope), and in a tropical environment, it will add up quickly. Classic positioning of the surface low in Alabama, upper low in Tenn Valley and damming high with tropical Pwat moisture, so easily a 10" rainfall in southwest NC and northeast GA mtns, and near extreme northwest SC probably just under 10".

The damming on GFS and ECMWF has surface temps into mid 60s for NC during the day Tuesday, some upper 50's shown on Euro and especially Tuesday night.

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Weather.com just went with a huge shift east on their rain totals. Western NC added to 6-10 and removed western/central Tennessee.

map_specnews08_ltst_4namus_enus_600x338.jpg

TOR:CON index

Forecast for Monday, September 5

AL - 6

FL panhandle - 4

GA north, west - 5

GA central - 4

MS southeast, east-central - 4

NC southwest - 4

SC northwest - 4

TN east - 4

Other areas - less than 2

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Weather.com just went with a huge shift east on their rain totals. Western NC added to 6-10 and removed western/central Tennessee.

map_specnews08_ltst_4namus_enus_600x338.jpg

TOR:CON index

Forecast for Monday, September 5

AL - 6

FL panhandle - 4

GA north, west - 5

GA central - 4

MS southeast, east-central - 4

NC southwest - 4

SC northwest - 4

TN east - 4

Other areas - less than 2

Funny that. The past two summers in Knoxville (plus new construction) has forced me to install a new irrigation system in my lawn next week. I somehow think 6 to 10 inches for us in Knox is a stretch, but hey, I'll take it because I'm tired of watering.

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Good discussion. I believe this statement is not exactly true. Tornadoes don't care about what feature is causing them. If the ingredients are there, they will form. While big CAPE is not associated with TC's, as you mentioned with the cold/dry air aloft, the other ingredients, vertical wind shear, low LCLs, low CIN can be there in abundance, depending on the strength of the TC. Climatological studies of TC tornadoes show that rarely are there EF3 or greater events, probably b/c of the lack of CAPE (kinda similar result with cool-season QLCS tornadoes), but if dry air can be entrained, you can have hybrid TCs with more CAPE. Usually this occurs with weaker TC's, so somewhat balances the parameters out. I like to look at Sig Tor Parameter, even with TC tors.

If the dry air could wrap around Lee some more, we could see a hybrid TC. This occurred with Cindy in July 2005 in Georgia and produced 6 tornadoes. Note the similarity in clouds/precip between Cindy and Lee. Cindy also moved in a path similar to Lee.

464px-Hurricane_Cindy_2005-07-05.jpg

671px-Cindy_2005_track.png

Others that have lived here longer than me could probably provide other better analogs. A few have been brought up in this thread and the main Lee thread.

Yep, it was Cindy that caused the airport and racetrack tornado, and not Ivan, like I'd been thinking. I looked it up the other day, and, indeed it was Cindy. She spun one up in Fayette County and sent one into the race track and airport next door... ef2 or maybe even a 3. I know there were more than reported, because f0 or big wind came between the two houses here and got three trees, and a few minutes later the race track was hit and I'm due south of the track. Lots of doppler indicated and pretty scary for a time. T

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Good discussion. I believe this statement is not exactly true. Tornadoes don't care about what feature is causing them. If the ingredients are there, they will form. While big CAPE is not associated with TC's, as you mentioned with the cold/dry air aloft, the other ingredients, vertical wind shear, low LCLs, low CIN can be there in abundance, depending on the strength of the TC. Climatological studies of TC tornadoes show that rarely are there EF3 or greater events, probably b/c of the lack of CAPE (kinda similar result with cool-season QLCS tornadoes), but if dry air can be entrained, you can have hybrid TCs with more CAPE. Usually this occurs with weaker TC's, so somewhat balances the parameters out. I like to look at Sig Tor Parameter, even with TC tors.

If the dry air could wrap around Lee some more, we could see a hybrid TC. This occurred with Cindy in July 2005 in Georgia and produced 6 tornadoes. Note the similarity in clouds/precip between Cindy and Lee. Cindy also moved in a path similar to Lee.

464px-Hurricane_Cindy_2005-07-05.jpg

671px-Cindy_2005_track.png

Others that have lived here longer than me could probably provide other better analogs. A few have been brought up in this thread and the main Lee thread.

Steve, thanks for posting and reminding us about Cindy! She had totally slipped my mind. I too apreciate the video updates! Makes it a whole lot more clear the FFC's thoughts surrounding their disco.

Robert, as always, thanks for your input. So informative!

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And thanks for the kudos about the VideoCasts. Other offices have been doing this sort of thing for a while. Our web team did all the setup and training and deserve the credit.

Do you know if it should work on an iPad? Been trying to view it with no luck (from the link on ffc's home page)

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From NWS Tallahassee. I would think the tornado risk might be higher closer to the storm track than SE AL is more like the Montgomery and Birmingham areas. I noticed TWC gives AL a 6 torcon for Monday but FL panhandle a 4 which would sound like they mean central and north AL rather than South AL?

REGARDING THE ISOLATED TORNADO POTENTIAL...SEVERAL THINGS ABOUT THISSYSTEM ARE A BIT CONCERNING. OUR AREA WILL BE LOCATED WITHIN THEBROAD RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET STREAK OVER THENORTHEAST U.S. WHICH WILL PROVIDE GENERAL SYNOPTIC SCALE LIFT. ATTHE SAME TIME...850 MB FLOW OF 50 TO 60 KNOTS IS FORECAST BY THE GFSTO TRAVERSE THE WESTERN HALF OF THE FORECAST AREA AS A 996 MB LOWMOVES THROUGH CENTRAL ALABAMA. 0-1 KM SHEAR OF AROUND 30 KNOTS ISFORECAST OVER SOUTHEAST ALABAMA ON MONDAY AFTERNOON...JUXTAPOSED WITHDEWPOINTS IN THE LOW TO MID 70S AND FORECAST SBCAPE VALUES OVER 1000J/KG. DIRECTIONAL SHEAR LOOKS ADEQUATE AND 0-1 KM HELICITY VALUESARE FORECAST BETWEEN 200-300 M2/S2. THE PRESENCE OF THE MID LEVELDRY AIR IN THE SYSTEM MAY ALSO ENHANCE THE RISK OF STORMS.OVERALL...THE POSITION OF THE UPPER LEVEL JET...THE STRENGTH ANDORGANIZATION OF THE 850 MB FLOW AND MSLP PATTERN...AND THE PRESENCEOF THE MID LEVEL DRY AIR ARE ALL KNOWN FACTORS THAT PREVIOUSRESEARCH HAS SHOWN MAY CONTRIBUTE TO TROPICAL CYCLONE TORNADOESALONG THE GULF COAST. (SEE THE COHEN DECEMBER 2010 PAPER ON GULFCOAST TROPICAL CYCLONE TORNADOES IN THE NATIONAL WEATHER DIGEST)
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And thanks for the kudos about the VideoCasts. Other offices have been doing this sort of thing for a while. Our web team did all the setup and training and deserve the credit.

The addition of the updated graphics on the homepage and the great videocast are awesome! I honestly was very impressed seeing the web briefing video. I hope this is something that you guys plan to continue for big systems from now on because it is very cool and really explains a lot of detail on forecast reasoning, etc.

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Well, its getting close to the major rainfall event of 2011 lol. Personally, I like the system to track north eastward through the Tennessee and North Carolina border. I think that throughout the southeast, heavy rain will be plentiful. Staying close to home, western Tennessee could see anywhere from 6-9 inches of rain. In the mountains of North Carolina, they can expect to see 4-8 inches of rain. The southern mountains and Blue Ridge mountains east facing slopes could see anywhere from 8-12 inches of rain. The foothills of North Carolina could see anywhere from 4-6 inches of rain and the piedmont of North Carolina could see anywhere from 3-5 inches of rain. These amounts could increase or decrease with the final track of Lee; however, this is my best guess right now. We'll see how it goes. Hopefully here in Hickory we can get a good 4-6 inches of rain; however, the rain is not going to be fun driving back up the mountain to UNC-Asheville in! :lol:

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