griteater Posted September 3, 2011 Share Posted September 3, 2011 GFS Monday Evening. For the I-85 corridor, this is a VERY moist look... Link to comment Share on other sites More sharing options...
Blue Ridge Posted September 3, 2011 Share Posted September 3, 2011 Starting Sunday, we're probably in for about a week of clouds and atleast showers. This run keeps the closed trough in the TN valley or Ohio Valley, and does bring periods of rain and storms for a while. Would be a nice, wet week of much needed rains for sure. I can't help but think the GFS is still under-doing the amounts in NC mtns with good upslope flow for a long time, but 5"to 7" is still a lot of rain. We will know soon how much the northern stream affects the southern stream. Its going to be a delicate act to get just the right amount of influence for our area. West of the Apps in Al and nw GA is a no brainer. Major rains there. I can't help but feel the Apps may be ground zero for much of this, given the location of the front and trough and mountains' ability to enhance lift and thus precip output. I've never seen a tropical system move in with this type of setup, though knowing what flooding other, faster-moving tropical systems have done to the area isn't highly encouraging... Link to comment Share on other sites More sharing options...
Gastonwxman Posted September 3, 2011 Share Posted September 3, 2011 While this will be fantastic news for most of the SE, it still means quite a lot of flooding for some areas, especially those that are caught in the consistent heavier precipitation bands. One of the better things about Lee is that he's not landfalling as a hurricane and so the wind will be at least kept in check. It's too bad that we don't have a second feature to give Texas beneficial rainfall. I'd imagine that scenario to be a case where a second surface low developed and made its own way toward the Texas coast, whether or not it eventually became a named system. That way both the SE and DS can be satisfied. By the way, can you imagine if this were winter and we had a setup where there was cold enough air out ahead of this? These QPF totals would have equated to a substantial snowstorm. Sadly we're in the wrong season for that. Link to comment Share on other sites More sharing options...
Sonny WX Posted September 3, 2011 Share Posted September 3, 2011 Date: 09/03/2011 Time: 4:20 CDT I awoke at 4:00 with steady moderate rain outside. Looking at the IR satellite loop, circulation of northern half of system is quite visible over south Louisiana. Looking at another tool I have, various tornado warnings have occurred in the last while. From the 4:00 am CDT Public Advisory.... NNW or N movement for the next 24 hrs, with a gradual turn to the NE expected. Expected to move slowly across southern Louisiana tomorrow. Landfall this afternoon or tonight in south Louisiana. Pressure has fallen to 995 mb, max sustained winds increased to 50 mph, and forward speed increased to 7 mph since I went to bed. BULLETIN TROPICAL STORM LEE ADVISORY NUMBER 7 NWS NATIONAL HURRICANE CENTER MIAMI FL AL132011 400 AM CDT SAT SEP 03 2011 ...LEE PRODUCING HEAVY RAINS OVER SOUTHERN LOUISIANA WITH TROPICAL STORM CONDITIONS ALONG THE COAST... SUMMARY OF 400 AM CDT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...28.8N 91.9W ABOUT 75 MI...120 KM SW OF MORGAN CITY LOUISIANA ABOUT 95 MI...155 KM S OF LAFAYETTE LOUISIANA MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H PRESENT MOVEMENT...NNW OR 345 DEGREES AT 7 MPH...11 KM/H MINIMUM CENTRAL PRESSURE...995 MB...29.38 INCHES Link to comment Share on other sites More sharing options...
Sonny WX Posted September 3, 2011 Share Posted September 3, 2011 Thanks to Meteorologist Dave Nussbaum (Facebook handle) of our local ABC affiliate WBRZ Channel 2 here in Baton Rouge, I found Tornado Watch # 826 posted by SPC from 1:45 am CDT until 10:00 am CDT. It begins just east of Baton Rouge, with the next parish (county) over and extends across southern MS and AL into half of the FL panhandle. Here is the link: http://www.spc.ncep.noaa.gov/products/watch/ww0826.html Link to comment Share on other sites More sharing options...
NavarreDon Posted September 3, 2011 Share Posted September 3, 2011 Looks like mutiple tornado warnings in S. LA this am. Seems like they are Doppler indicated after a quick read. http://www.srh.noaa.gov/lix/ Link to comment Share on other sites More sharing options...
NavarreDon Posted September 3, 2011 Share Posted September 3, 2011 Weenie question here. I was wondering if someone could explain about a low opening up & then closing? What does that mean weather wise? From GSP: .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 230 AM SATURDAY...THE SHORT TERM FCST PICKS UP AT 12Z ON SUNDAY WITH THE NORTHERN STREAM UPPER TROF DIGGING DOWN OVER THE WESTERN GREAT LAKES AND STARTING TO BECOME IN PHASE WITH THE CLOSED H5 TROPICAL LOW ANCHORED OVER SOUTHERN LOUISIANA. BY 12Z MONDAY...THE GREAT LAKES TROF HAS MOVED FARTHER EAST AND IS BEGINNING TO OPEN UP THE CLOSED LOW. CURRENT MODEL CONSENSUS SUGGESTS THAT THE LOW IS NEARLY PICKED UP BY THE NORTHERN STREAM TROF BUT IT IS MOVING TOO FAST AND BY THE END OF THE PERIOD AT 12Z ON TUES THE LOW IS BEGINNING TO CLOSE AGAIN. ON SUNDAY...AS THE BERMUDA HIGH BEGINS TO STRENGHTEN WELL OFFSHORE SOUTHEASTERLY UPSLOPE BOUNDARY LAYER FLOW WILL STRENGHTEN OVER THE CWFA. LATE SUN EVENING THE SFC FRONTAL BOUNDARY WILL APPROACH THE NC/TN BORDER FROM THE NW AND BRING DEEP LAYER MOISTURE AND AN IMPRESSIVE LOW LVL CONVERGENCE ZONE THAT STRETCHES FROM THE GREAT LAKES TO THE LA/MISS REGION. LATEST MODEL SOUNDINGS RAMP UP PWAT VALUES LATE SUN EVENING AFTER ABOUT 10PM AND KEEP THEM OVER 2 INCHES THRU THE END OF THE PERIOD AT 12Z ON TUES. I RAMP POPS UP TO LIKELY OVER MOST OF THE MTS BY 00Z MON AND HAVE CATEGORICAL OVER ROUGHLY THE NW PORTION OF THE CWFA BY 18Z MON...AND LIKELY ELSEWHERE AND MAINTAIN LIKELY INTO THE MEDIUM RANGE. ITS STILL LOOKING LIKE THE MAIN THREATS DURING THE PERIOD WILL BE COPIUS AMOUNTS OF RAIN WHICH COULD TRIGGER WIDESPREAD FLOODING AND FLASH FLOODING. THERE WILL LIKELY BE SMALL AMOUNTS OF INSTABILITY COUPLED WITH HEALTHY LOW LVL HELICITY AND 0-6KM BULK SHEAR DURING THE AFTERNOON/EVENING...HOWEVER THE TROPICAL LIKE SOUNDINGS WILL LIKELY MAKE IT TOUGH FOR ANY SVR CONVECTION TO BE GENERATED. TEMPS WILL DROP WELL BELOW CLIMO ON MON AND TUES AS THE COLD FRONT PUSHES THRU THE AREA AND AMPLE CLOUD COVER PERSISTS. I BUMPED HIGHS DOWN TO AROUND 80 ON MON AND UPPER 70S ON TUES FOR THE SC UPSTATE REGION. Link to comment Share on other sites More sharing options...
kayman Posted September 3, 2011 Share Posted September 3, 2011 Looks like mutiple tornado warnings in S. LA this am. Seems like they are Doppler indicated after a quick read. http://www.srh.noaa.gov/lix/ I see the tornado threat is revving up with this system! I don't feel like having to be concerned about this issue come Monday when I have to get back to Auburn... Link to comment Share on other sites More sharing options...
Sonny WX Posted September 3, 2011 Share Posted September 3, 2011 Looks like mutiple tornado warnings in S. LA this am. Seems like they are Doppler indicated after a quick read. http://www.srh.noaa.gov/lix/ A lot of Tornado warnings are doppler indicated, here anyway. When our local storm spotters are able to be watching, we usually get visual confirmation of those that actually occur. The general public also calls local radio or tv stations sometimes with confirmations too. Link to comment Share on other sites More sharing options...
Sonny WX Posted September 3, 2011 Share Posted September 3, 2011 I see the tornado threat is revving up with this system! I don't feel like having to be concerned about this issue come Monday when I have to get back to Auburn... I was thinking last night that northern AL could be in line for a repeat of April 27. The northeastern quadrant will be most likely, and as Lee moves out of LA into MS and AL, this will be one thing to watch, for sure. Link to comment Share on other sites More sharing options...
DixieBlizzard Posted September 3, 2011 Share Posted September 3, 2011 I was thinking last night that northern AL could be in line for a repeat of April 27. The northeastern quadrant will be most likely, and as Lee moves out of LA into MS and AL, this will be one thing to watch, for sure. Not even close! You will not see discrete, super-cell structures anywhere near Alabama (or the USA) until next spring. Totally different setup here. Link to comment Share on other sites More sharing options...
NavarreDon Posted September 3, 2011 Share Posted September 3, 2011 I was thinking last night that northern AL could be in line for a repeat of April 27. The northeastern quadrant will be most likely, and as Lee moves out of LA into MS and AL, this will be one thing to watch, for sure. Not a tornado expert but imo this is really not likely. If it did happen it would be volume & not intensity. April outbreak had so many long track powerful tornadoes. Tornadoes spawned from a tropical cyclone are normally short track and EF0, EF1 or rarely EF2. Link to comment Share on other sites More sharing options...
Snowless in Carrollton Posted September 3, 2011 Share Posted September 3, 2011 Not a tornado expert but imo this is really not likely. If it did happen it would be volume & not intensity. April outbreak had so many long track powerful tornadoes. Tornadoes spawned from a tropical cyclone are normally short track and EF0, EF1 or rarely EF2. But isn't there a strong cold front moving south that could interact with the tropical system and cause more tornadoes and stronger tornadoes than normally would be the case with a tropical system ? Link to comment Share on other sites More sharing options...
NavarreDon Posted September 3, 2011 Share Posted September 3, 2011 But isn't there a strong cold front moving south that could interact with the tropical system and cause more tornadoes and stronger tornadoes than normally would be the case with a tropical system ? I am really not the person to answer your question in all honesty. I will let one of the more tornado educated posters answer it. I do know enough to say if there are tornadoes from Lee it will be nothing like April. Link to comment Share on other sites More sharing options...
Marion_NC_WX Posted September 3, 2011 Share Posted September 3, 2011 But isn't there a strong cold front moving south that could interact with the tropical system and cause more tornadoes and stronger tornadoes than normally would be the case with a tropical system ? Tornadoes that form inside tropical systems is a completely different animal compared to your textbook spring storm systems...Tornadoes are not just about wind shear, you also need the cold air aloft and dry air at the mid levels in order to get the violent cells to form on their own... both of those factors don't exist when you have the air mass of a tropical system. Link to comment Share on other sites More sharing options...
DaculaWeather Posted September 3, 2011 Share Posted September 3, 2011 A tornado in this environment is usually spun up by the differential with the winds at the lower levels versus the higher levels. In a hurricane, the winds at the ground are slower than the winds further up (and that level is not high in a hurricane, maybe 3000 feet or so). That differential and change of direction can spin a small one up very quickly and without notice. Link to comment Share on other sites More sharing options...
calculus1 Posted September 3, 2011 Share Posted September 3, 2011 06Z GFS seems to be much more progressive with this system than previous runs. All rain is out of the SE by Tuesday evening if this run is correct. The faster movement of Lee also serves to steer Katia back out to sea and not allow her to get too close to the NC coast. Link to comment Share on other sites More sharing options...
DaculaWeather Posted September 3, 2011 Share Posted September 3, 2011 It sure looks like to me that the largest area of rain and cloud cover is WELL to the east of the center. If this follows the path that is suggested right now, I don't see how the estimated rainfall is going to fall where they say, I see it it further east (instead of MS/TN more AL/GA). There is absolutely nothing on the back side of this. I'm assuming the models believe that there will be some interaction with a front to generate heavy rainfall over that area? Maybe I'm wrong but I'm sticking with it. Link to comment Share on other sites More sharing options...
EmersonGA Posted September 3, 2011 Share Posted September 3, 2011 Im in pensacola visiting family for the weekend. While not comparable to what Louisiana is getting we had an impressive band move through awhile ago. Very heavy rain and strong wind. It should be an interesting couple of days. Ill lead the rain back north with me for all of yall. Link to comment Share on other sites More sharing options...
NavarreDon Posted September 3, 2011 Share Posted September 3, 2011 Im in pensacola visiting family for the weekend. While not comparable to what Louisiana is getting we had an impressive band move through awhile ago. Very heavy rain and strong wind. It should be an interesting couple of days. Ill lead the rain back north with me for all of yall. Gonna make for a crappy Labor day weekend for alot of people.....unless you are a weather nut! Link to comment Share on other sites More sharing options...
FoothillsNC Posted September 3, 2011 Share Posted September 3, 2011 It sure looks like to me that the largest area of rain and cloud cover is WELL to the east of the center. If this follows the path that is suggested right now, I don't see how the estimated rainfall is going to fall where they say, I see it it further east (instead of MS/TN more AL/GA). There is absolutely nothing on the back side of this. I'm assuming the models believe that there will be some interaction with a front to generate heavy rainfall over that area? Maybe I'm wrong but I'm sticking with it. What should happen is the front will begin to create lift against the perpendicular flow, and that would be on the northwest semi-circle of the storm, atleast for the first half of the next 5 days, so that places northern Miss, nw Ala, central and western TN in the heavy rain side. The SREF shows it nicely and the ECM and GFS also showed it happening. But its going to come down to how the front is oriented and what track the center of circ. takes. Either way, the northern and western sides initially will be the area for the real flooding rains for a couple of days, but the front may drape more east to west (and even damming shape by late Tues) and then the axis of heavy rains shift there (ne GA /Carolinas) Link to comment Share on other sites More sharing options...
Marion_NC_WX Posted September 3, 2011 Share Posted September 3, 2011 What should happen is the front will begin to create lift against the perpendicular flow, and that would be on the northwest semi-circle of the storm, atleast for the first half of the next 5 days, so that places northern Miss, nw Ala, central and western TN in the heavy rain side. The SREF shows it nicely and the ECM and GFS also showed it happening. But its going to come down to how the front is oriented and what track the center of circ. takes. Either way, the northern and western sides initially will be the area for the real flooding rains for a couple of days, but the front may drape more east to west (and even damming shape by late Tues) and then the axis of heavy rains shift there (ne GA /Carolinas) I noticed on the 6z GFS that the surface low parallels I-85 as it moves from Northeast GA to North Carolina... That in itself should provide the Blue Ridge a perfect position on that north and northwest quad. Then you add SE upslope prior to the main core, frontal boundary and other factors that should provide quite a bullseye over Western Carolinas, especially west of 321... Given the fact that the 6z was more progressive, I would think we are in line for a 4-6 inch rainfall along the escarpment...if its not as progressive, 6-10 could be a better call. Link to comment Share on other sites More sharing options...
DaculaWeather Posted September 3, 2011 Share Posted September 3, 2011 What should happen is the front will begin to create lift against the perpendicular flow, and that would be on the northwest semi-circle of the storm, atleast for the first half of the next 5 days, so that places northern Miss, nw Ala, central and western TN in the heavy rain side. The SREF shows it nicely and the ECM and GFS also showed it happening. But its going to come down to how the front is oriented and what track the center of circ. takes. Either way, the northern and western sides initially will be the area for the real flooding rains for a couple of days, but the front may drape more east to west (and even damming shape by late Tues) and then the axis of heavy rains shift there (ne GA /Carolinas) Thanks Robert! Link to comment Share on other sites More sharing options...
downeastnc Posted September 3, 2011 Share Posted September 3, 2011 What should happen is the front will begin to create lift against the perpendicular flow, and that would be on the northwest semi-circle of the storm, atleast for the first half of the next 5 days, so that places northern Miss, nw Ala, central and western TN in the heavy rain side. The SREF shows it nicely and the ECM and GFS also showed it happening. But its going to come down to how the front is oriented and what track the center of circ. takes. Either way, the northern and western sides initially will be the area for the real flooding rains for a couple of days, but the front may drape more east to west (and even damming shape by late Tues) and then the axis of heavy rains shift there (ne GA /Carolinas) As long as it stays away from the eastern parts of NC I am happy, a few inches wouldnt be a big deal but anymore than that up river and we are right back into flood stage and 6-10" would be issue. Link to comment Share on other sites More sharing options...
SN_Lover Posted September 3, 2011 Share Posted September 3, 2011 Although, North Carolina is not in a really bad drought. The majority of big lakes in the piedmont and foothills are running below average levels. Levels are Lake Norman(now in low inflow stage 1) are at levels that would be observed in winter. Any rain would certainly be welcome. Link to comment Share on other sites More sharing options...
AbsolutZero Posted September 3, 2011 Share Posted September 3, 2011 Tornadoes that form inside tropical systems is a completely different animal compared to your textbook spring storm systems...Tornadoes are not just about wind shear, you also need the cold air aloft and dry air at the mid levels in order to get the violent cells to form on their own... both of those factors don't exist when you have the air mass of a tropical system. 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. 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. Link to comment Share on other sites More sharing options...
blueheronNC Posted September 3, 2011 Share Posted September 3, 2011 If ever there were a "perfect storm" setup for the upslope and foothills regions of NC, this is it if the 12z GFS plays out. We start with the mountains and foothills absolutely SLAMMED by tropical PWAT air ringing out inches upon inches of rain in the Sunday-early Tuesday timeframe. Then, as Lee transitions over to an extratropical entity, we get a warm-season CAD event across the foothills and NC piedmont region. A crazy setup. All in all, I would not be surprised to see places in favored upslope areas such as Highlands/Cashiers get 15-20 inches of rain. Link to comment Share on other sites More sharing options...
LithiaWx Posted September 3, 2011 Share Posted September 3, 2011 What an odd looking system. You can see it has quite a broad circulation, I would love to see what this looks like if it can finally wrap it's self up and move some of that convection over the SW part of the storm. Link to comment Share on other sites More sharing options...
EmersonGA Posted September 3, 2011 Share Posted September 3, 2011 It kind of looks like the 93 superstorm to me. It has a noreaster look to me. We are in an absolute downpour here in Pensacola right now. Link to comment Share on other sites More sharing options...
DaculaWeather Posted September 3, 2011 Share Posted September 3, 2011 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. 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. Good stuff, thanks Steve. Also, I REALLY like you video updates, very informative with good use of graphics. In case anyone hasn't seen the latest: http://www.srh.noaa.gov/media/ffc/videocast/Lee/player.html Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.