ATL_Militarypolice Posted April 20, 2011 Share Posted April 20, 2011 Models have been hinting at another potential severe weather event from the Central Plains east into our region sometime in the middle of next week. Models bring a very potent long-wave trough moving into the Central Plains around Tuesday of next week. With the Bermuda high off the east coast we manage to keep southerly flow at the surface bringing in warm-moist Gulf airmass across the entire region, with widespread Tds in the 60-70 degree range from the Ohio Valley to the Gulf coast, well in advance of this developing system. This is still a week out, but taking a look at last night's 0Z model group, something pretty significant looks to be brewing. Once again hodo's are long and loop clockwise with impressive 0-3KM helicity being shown. As HUN mentioned in their AFD the Euro is the slowest of the Global models as it digs the trough further south than the GFS. With the GFS bringing the front into western sections of the southeast by 0Z Wed, into Alabama and Central Tennessee ~12Z, and eventually working east into the Central Carolinas ~0Z Thursday. Link to comment Share on other sites More sharing options...
ATL_Militarypolice Posted April 21, 2011 Author Share Posted April 21, 2011 Henry on Accuwx... Link to comment Share on other sites More sharing options...
eyewall Posted April 21, 2011 Share Posted April 21, 2011 Henry on Accuwx... Wow nice way to build up the fear for NC residents trying to recover from this past saturday Link to comment Share on other sites More sharing options...
eyewall Posted April 21, 2011 Share Posted April 21, 2011 Looking at the 12z GFS verbatim it is trying to have CAPE approach 1000 in a narrow band in NC along and plenty of shear for the 28th. Even 0-925mb was 35-40 knots. Of course this will likely change being it is 160+ hours out. Link to comment Share on other sites More sharing options...
LithiaWx Posted April 21, 2011 Share Posted April 21, 2011 It appears the onslaught of tornadoes and severe thunderstorms that have claimed dozens of lives and left communities in ruins from the Plains into the East over the past few weeks is going to continue right into next week. Next up is another significant outbreak set to hit areas from Oklahoma to Ohio Friday into Friday night. After that, AccuWeather.com severe weather experts are already greatly concerned about the tornado potential with a series of storm systems set to track across the hard-hit Plains, Midwest and Southeast throughout next week. "This could be more widespread than anything we've seen this season," said AccuWeather.com Expert Senior Meteorologist Dan Kottlowski. "We're going to see multiple outbreaks of severe weather Monday, Tuesday and Wednesday next week from the Ohio Valley to the southern Plains and into the southeastern U.S.," Kottlowski explained. "The orientation of upper-level winds with this setup look to favor a high risk of tornado development." "People should review tornado safety guidelines and take any [severe thunderstorm or tornado] watches and warnings very seriously," Kottlowski stressed. While severe thunderstorms with this outbreak could get under way as early as late Sunday, the main threat will evolve Monday through Wednesday. Kottlowski said that Tuesday and Wednesday will be particularly bad and that the Ohio and Tennessee valleys and the Deep South are the most likely areas to be hit multiple times. The number of tornadoes so far in 2011 has already surpassed the number up to this point in 2008, which had the second highest number of tornadoes on record, according to AccuWeather.com Senior Meteorologist Henry Margusity. This number will only continue to climb through next week. Margusity said Tuesday that he thinks there could be up to 300 tornadoes from April 19 to May 4. Since making that statement, there have been 42 reports of tornadoes with a storm system that pushed through the Plains, South and Midwest Tuesday into Wednesday. "There is no doubt between the recent event [Tuesday into Wednesday] and the weather pattern next week that we will see 300 tornadoes," Margusity stated. "People from the Plains into the East really need to pay attention to the weather." http://www.accuweath...rnadoes-com.asp It's not like they have ever been wrong before right? In all seriousness they are hyping it up pretty good over there. Time will tell and it surely would not surprise me even a little bit if this was the worst outbreak of the season like they are predicting is possible. Link to comment Share on other sites More sharing options...
CandymanColumbusGA Posted April 21, 2011 Share Posted April 21, 2011 I noticed this yesterday morning.... The trough that digs into the Central Plains is impressive! All the players are on the table for a pretty big outbreak, one that could rival last weeks 200+ tornado outbreak. The effects in the southeast won't be until Tuesday night/Wednesday morning. The way the LLJ is setting up, it looks like I'll be on the fringe of seeing severe weather, but those in North Georgia and Alabama and especially the Carolinas need to keep an eye on this system. I generally don't look at CAPE this far out, but it looks fairly impressive for being 5 days out. We will have to see if the storms weaken as they cross Interstate 65, like they did with yesterday's and today's system... (That was beyond frustrating seeing it weaken as it got close to my viewing area... many people were like where's the rain.... ) Of course things are going to change over the next 5/6 days, but I already have a bad feeling about this. Link to comment Share on other sites More sharing options...
Gastonwxman Posted April 21, 2011 Share Posted April 21, 2011 Likewise regarding the hype. It's one thing to say that there is potential, but it's an entirely different ball game when you claim something like a major severe weather outbreak is imminent, let alone stating that 300 tornadoes will develop. The setup for next week does look favorable for producing a rather potent system to swing through the eastern half of the country, with numerous severe/super cells breaking out for certain areas. However, I really don't think one can make such an assumption (not yet at least), especially for something like this to occur (and as Eyewall said earlier, putting a scare in some folks recently recovering from the previous event). It's true that this past weekend's devastating tornadic outbreak is one example of what this year's weather is capable of producing (which I think modeling did a pretty good job on), but many a time I've seen setups like this where one wrong move in the process can make it turn out to not be as bad as most originally thought just like the past two events have done for some. Regardless, in a volatile pattern such as this it's ANYTHING GOES for this Spring season and so far April has kept its promise for providing plenty of severe action across the Southeast, so I will agree to an extent that the idea of a major tornado outbreak is possible for a good chunk of us and other regions in the eastern half of the US between now and early May. The month of May will probably continue this until we eventually reach a point where pop-up storms are the common weather events that occur. Will be interesting to see how it plays out in the end. Just my thoughts on the concept but nice to see that something could give our friends in the eastern sections of the Carolinas more rain (as well as the rest of the folks who have been missing out). Link to comment Share on other sites More sharing options...
CandymanColumbusGA Posted April 21, 2011 Share Posted April 21, 2011 Likewise regarding the hype. It's one thing to say that there is potential, but it's an entirely different ball game when you claim something like a major severe weather outbreak is imminent, let alone stating that 300 tornadoes will develop. The setup for next week does look favorable for producing a rather potent system to swing through the eastern half of the country, with numerous severe/super cells breaking out for certain areas. However, I really don't think one can make such an assumption (not yet at least), especially for something like this to occur (and as Eyewall said earlier, putting a scare in some folks recently recovering from the previous event). It's true that this past weekend's devastating tornadic outbreak is one example of what this year's weather is capable of producing (which I think modeling did a pretty good job on), but many a time I've seen setups like this where one wrong move in the process can make it turn out to not be as bad as most originally thought just like the past two events have done for some. Regardless, in a volatile pattern such as this it's ANYTHING GOES for this Spring season and so far April has kept its promise for providing plenty of severe action across the Southeast, so I will agree to an extent that the idea of a major tornado outbreak is possible for a good chunk of us and other regions in the eastern half of the US between now and early May. The month of May will probably continue this until we eventually reach a point where pop-up storms are the common weather events that occur. Will be interesting to see how it plays out in the end. Just my thoughts on the concept but nice to see that something could give our friends in the eastern sections of the Carolinas more rain (as well as the rest of the folks who have been missing out). I completely agree Gaston! That's why it was the last thing I quickly mentioned in my weathercasts this morning... There is no need to get the general public up in arms about a HUGE tornado outbreak that will happen next week... because you know what will happen? NOTHING! That would completely destroy our credibility to our viewers. However, if we just say, "Stay with us early next week as we could be looking at a pretty strong system that might give us a few strong storms in the middle of next week." That doesn't sound the alarm bells just yet, but it gets the potentially dangerous system on their radar. I'm all for keeping people calm, because calm people are happy people . I also agree about the incredible month of April we have had! I've had 3 tornadoes (albeit weak ones) touch down in my viewing area (One during the Florida-Butler game and not anywhere NEAR the major cities... but that's a different story for a different day). I wouldn't be surprised, like you said, to see this go well into the month of May. The only thing that could stop that from happening is the ridge's placement. We'll just have to see how this all pans out the next few weeks.... OH! On a side note... I really hope this happens during the day! The past 4 severe weather events have happened overnight (I'm the morning Met...) and I need to catch up on sleep! Link to comment Share on other sites More sharing options...
Gastonwxman Posted April 22, 2011 Share Posted April 22, 2011 The next system definitely will be worth watching as GFS continues to advertise the front to have quite an attitude with the advancing trough/cold front heading in a eastward direction. Timing couldn't be better on the 0z GFS's part as it brings this feature through GA during the morning and the Carolinas during the day Thursday, particularly in the afternoon. Rain totals are tremendous per HPC's expected totals. I sense some major flooding going on for parts of the MS Valley/Midwest. Link to comment Share on other sites More sharing options...
HKY_WX Posted April 22, 2011 Share Posted April 22, 2011 I was just noticing this when browsing the GFS. This IMO has a chance to impact areas in western and central NC as well. This could be a very intense svr wx event.Looks like wednesday-thursday of next week is target date around GA/SC/NC.You're talking about bringing in a strong upper/sfc low with close to 0C temps aloft(850mb) into a humid 80's airmass. Could be a huge widespread event from TX to the east coast. Nasty looking setup Makes sense given the AO forecast and the strong cold air sitting over Canada. Link to comment Share on other sites More sharing options...
FoothillsNC Posted April 22, 2011 Share Posted April 22, 2011 looks similar to the Derecho-type of event a couple weeks ago, when winds topped 70mph over a lot of counties. http://www.shelbyweather.blogspot.com Link to comment Share on other sites More sharing options...
Lookout Posted April 22, 2011 Share Posted April 22, 2011 Good discussion in this thread guys. Although it's a long ways out, will go ahead and pin this since I'm sure many will be tracking this daily and the discussion is good. Many of you have been outstanding this spring and the southeast group has really shined and once again proving this group is the top of the class on this board IMHO. Link to comment Share on other sites More sharing options...
weatherman566 Posted April 22, 2011 Share Posted April 22, 2011 Yeah, this upcoming storm system will be awful for Mississippi and Alabama, weaken and fizzle out over Georgia, and ramp up again in the Carolinas. I guess that's a good thing if you live in Georgia. However, I want to see some awesome storms.....in the daytime. I am so sick of nighttime storms moving through GA and weakening. It really takes all the fun out of everything. Also, I'm sick of night storms. It happened all of the time in the winter, and it's doing it again this Spring. SO ANNOYING! Sorry for my rant. Link to comment Share on other sites More sharing options...
LithiaWx Posted April 22, 2011 Share Posted April 22, 2011 Yeah, this upcoming storm system will be awful for Mississippi and Alabama, weaken and fizzle out over Georgia, and ramp up again in the Carolinas. I guess that's a good thing if you live in Georgia. However, I want to see some awesome storms.....in the daytime. I am so sick of nighttime storms moving through GA and weakening. It really takes all the fun out of everything. Also, I'm sick of night storms. It happened all of the time in the winter, and it's doing it again this Spring. SO ANNOYING! Sorry for my rant. It seems at first glance it would be too soon to say things will fizzle out over Georgia. It might be my inner weenie but we shall see. Link to comment Share on other sites More sharing options...
ATL_Militarypolice Posted April 22, 2011 Author Share Posted April 22, 2011 12Z GFS develops an ULL over Kansas/Missouri border and tracks it to southern Michigan, with the surface low tracking from central OK into the lower Ohio Valley. Strong vortex max and negative tilted trough pulls in a warm, moist airmass across the region with 60 Tds moving into the southern OH/IN/IL 12Z Wed with 65 Tds across a good majority of the Deep South/Southeast. There are even pockets of 70 Tds nosing north from southeastern MS into northwestern Alabama as the low continues to wrap up. A strong low level jet over 55Kts at 850MB with a 100KT jet streak at 500MB. SFC-500 MB shear AOA 80Kts along the front supports the potential for another widespread damaging wind event. Hodographs impressive ahead of the front with clockwise signatures, if any storm forms ahead of the line they could go tornadic quite easily especially given low LCL/LFC. Still 5-6 days out though... Link to comment Share on other sites More sharing options...
FoothillsNC Posted April 22, 2011 Share Posted April 22, 2011 Lots of similarities between next week's event and the one from early April. The 850 low is strong, actually this one progged to be a little stronger, the 5H begins neg tilt around TN valley again, warm sector major derecho type line already showing up on the GFS, which was pegged pretty nicely in that outbreak as well. However this run of GFS is a little more north, but I think the southern flank will easily be just as far south, the only difference may be this outbreak could be larger overall, from north to South. Another difference in 5H, the early April was more consolidated full=lat trough going neg, this one looks a little different , but not that much. Even though that one hit the Carolinas around midnight and after, the neg. tilt and deepening sfc low near Ohio was the reason the line remain strong and intensified coming east off the mountains, and so far its nearly a carbon copy onthe GFS, but the timing is bound to be off a little. The one main difference is the moisture return ahead of this is going to be high in the mid levels, as opposed to a sharp delineation or contrast, that may make a difference in the various instability indices, some would be pro, some con. The Bermuda high will be firmly in place, feeding rich gulf inflow. I personally don't care for any severe weather, its been a rough month, but of course any active weather lover likes the extremes that nature can show. So, meh. April 6 April 27 Link to comment Share on other sites More sharing options...
Gastonwxman Posted April 22, 2011 Share Posted April 22, 2011 Amongst all other things, some modeling is showing more support of convection with our next developing system due to a disturbance that will be entering the Southeast sometime between Tuesday night and through the day Wednesday. The addition of this feature can aid in strengthening the upper dynamics and supply more moisture to work with as the cold front traverses eastward. Track of this will determine how much support is given; the more westward, the better the chance. As far as timing goes, there is agreement between 0z Euro and 12z GFS as the front will cross into our area from Wednesday night and depart later in the day Thursday in attendance with a healthy secondary shortwave (both showing this feature) that will head into the OV. It's still tough to pin down exactly how things on the mesoscalic level will play out due to uncertainty of the nature of this setup, but would not surprise me if, as stated earlier, this turns out to be a scenario similar to the major gusty severe storms that we experienced earlier this month with strong bowing and of course with the progged shear values, super cellular development, which I understand none of us want to hear so soon but we have to mention the possibilities associated with this system and so would be more of a "keep in mind" kind of deal. Link to comment Share on other sites More sharing options...
Snowless in Carrollton Posted April 22, 2011 Share Posted April 22, 2011 FFC seems really concerned about next week. This is what they said : BOTH GFS AND ECMWF BRING A COUPLE OF SHORT WAVES ACROSS THE CWA...ONE ON TUESDAY AND ANOTHER WEDNESDAY. THIS WILL KEEP THE RISK OF CONVECTION IN THE FORECAST BEGINNING TUESDAY AND CONTINUING THROUGH THURSDAY NIGHT Link to comment Share on other sites More sharing options...
LithiaWx Posted April 22, 2011 Share Posted April 22, 2011 FFC seems really concerned about next week. This is what they said : BOTH GFS AND ECMWF BRING A COUPLE OF SHORT WAVES ACROSS THE CWA...ONE ON TUESDAY AND ANOTHER WEDNESDAY. THIS WILL KEEP THE RISK OF CONVECTION IN THE FORECAST BEGINNING TUESDAY AND CONTINUING THROUGH THURSDAY NIGHT What do you want/expect them to say? The event is 5 days away and still not a certainty. It would be stupid for them to say a big severe outbreak is coming. They need their credibility and if they started saying, the sky is falling and nothing serious happens they would lose their credibility. Candyman put it very well in a previous post. I completely agree Gaston! That's why it was the last thing I quickly mentioned in my weathercasts this morning... There is no need to get the general public up in arms about a HUGE tornado outbreak that will happen next week... because you know what will happen? NOTHING! That would completely destroy our credibility to our viewers. However, if we just say, "Stay with us early next week as we could be looking at a pretty strong system that might give us a few strong storms in the middle of next week." That doesn't sound the alarm bells just yet, but it gets the potentially dangerous system on their radar. I'm all for keeping people calm, because calm people are happy people . Link to comment Share on other sites More sharing options...
Snowless in Carrollton Posted April 22, 2011 Share Posted April 22, 2011 What do you want/expect them to say? The event is 5 days away and still not a certainty. It would be stupid for them to say a big severe outbreak is coming. They need their credibility and if they started saying, the sky is falling and nothing serious happens they would lose their credibility. Candyman put it very well in a previous post. Well I don't expect them to say we will have a huge tornado outbreak, but I think they should at least mention the possibility of severe storms. Link to comment Share on other sites More sharing options...
Gastonwxman Posted April 23, 2011 Share Posted April 23, 2011 The 0z GFS is giving me one heck of a scare and a great deal of concern for the folks back west in the Arklatex region, as well as Western TN and parts of the Gulf States. Take a look at the impressive jet structure of the 300 and 500 mb charts from the 96 hour. That is some impressive energy showing up around the trough, indicating very strong winds aloft. On top of that, you have temperatures soaring into the upper 80s-mid 90s with very high lapse rates at the mid and lower levels (around 9.5°C during the 96hr.), an abundance of moisture with a deepening surface low, SBCAPE approaching 3000 at some point and lots of lift. This has the looks of an exceptionally dangerous severe weather outbreak for them and would highly indicate some strong, long-tracked tornadoes breaking out. There's really not much else to say since the rest of the severe parameters speak for themselves (SRH +450 and EHI +4). Everyone over there needs to be on their guard because this has an intense look to it for sure. The Euro is not that much different either from what I can tell, so both are (as of now) suggesting quite a wallop for those areas. Hopefully it won't become this awful but it's been an ongoing solution for the longest time now and if I were anyway over there, I would be paying special attention to this. For what it translates further east across the rest of the Southeast, thankfully it doesn't appear to be as bad but there could be enough re-intensification that we'll be having tough issues on our end, which would be the combo of powerful gusty winds and large hail with some embedded supercells. Such a very dynamically-driven system indeed. Beyond this particular frame, if you look from hours 102-120 it shows the end result of all this with some very heavy rainfall for spots, especially across place such as TN where more than 3 or 4 inches of rain is possible. MO still seems to be the "hotspot" for the worst of it where several inches of rain could rack up. 300mb: 500mb: Lapse rates (trends a little weaker at the later frames east of TX/OK with values around 8°C or 8.5°C) Link to comment Share on other sites More sharing options...
ATL_Militarypolice Posted April 23, 2011 Author Share Posted April 23, 2011 Wow I never seen a NWS AFD mention long-tracking tornadoes this early. KMEM: MONDAY...A MORE CLASSIC SEVERE WEATHER PATTERN WILL SET UP AS ATROUGH SHIFTS OUT OF THE PLAINS. A 50-60 KNOT LLJ WILL DEVELOP OVER WESTERN PORTIONS OF THE MIDSOUTH MONDAY AFTERNOON AND A NEUTRAL TO SLIGHTLY NEGATIVELY TILTED SHORTWAVE WILL APPROACH THE MISSISSIPPI RIVER. ABUNDANT MOISTURE IS ALREADY IN PLACE...AND WILL REMAIN IN PLACE AHEAD OF THIS SYSTEM. DEWPOINTS IN THE MIDDLE 60S WILL PRODUCE CAPES NEAR 3000 J/KG AND LIFTED INDICES WILL RANGE FROM -6 TO -8 DEGREES. LOW AND MID LEVEL DYNAMICS SHOULD RESULT IN SUFFICIENT SHEAR TO SUPPORT SUSTAINED UPDRAFTS AND SUPER CELLULAR THUNDERSTORMS. DEEP DRY AIR ALOFT WILL LIKELY RESULT IN LARGE HAIL. TUESDAY WILL BE A TRANSITIONAL DAY...AS SOUTHERLY FLOW INCREASES ACROSS THE MIDSOUTH. SHOWERS AND THUNDERSTORMS WILL LIKELY CONTINUE...BUT ARE NOT EXPECTED TO BE SEVERE AS THE FIRST SHORTWAVE SHIFTS EAST OF THE AREA. TUESDAY NIGHT INTO WEDNESDAY AND ANOTHER MUCH STRONGER AND MORE NEGATIVELY TILTED SHORTWAVE WILL APPROACH THE MISSISSIPPI RIVER. SURFACE WINDS WILL BACK AS A SURFACE LOW TRACKS FROM CENTRAL ARKANSAS INTO WESTERN KENTUCKY RESULTING IN LONG CURVED HODOGRAPHS SUPPORTIVE OF SEVERE THUNDERSTORMS. TORNADOES...POSSIBLY STRONG LONG TRACKED TORNADOES...LARGE HAIL AND DAMAGING WIND ARE ALL POSSIBLE ON WEDNESDAY. CURRENT GUIDANCE IS SLIGHTLY FASTER WITH THIS SYSTEM...SO IT MAY NOT BE ABLE TO TAKE MAXIMUM ADVANTAGE OF DAYTIME INSTABILITY AS PREVIOUSLY EXPECTED. NEVERTHELESS...SHEAR PROFILES ALONE ARE ENOUGH TO RESULT IN SEVERE THUNDERSTORMS...AND EVEN IN A MARGINALLY UNSTABLE AIRMASS A SIGNIFICANT OUTBREAK IS POSSIBLE. Link to comment Share on other sites More sharing options...
ATL_Militarypolice Posted April 23, 2011 Author Share Posted April 23, 2011 ...DISCUSSION... SUBSTANTIAL SEVERE WEATHER POTENTIAL IS EXPECTED TO SHIFT SLOWLY EWD ACROSS THE ERN U.S. DAYS 4-6 /TUE. 4-26 THROUGH THU. 4-28/...AS A LARGE UPPER TROUGH PROGRESSES FROM THE CENTRAL U.S. DAY 4 ACROSS THE MS VALLEY DAY 5...AND THEN ON EWD THROUGH DAYS 6/7. MODEL DIFFERENCES WITH RESPECT TO TIMING OF THIS FEATURE BEGIN TO EMERGE DAY 5...BUT BECOME INCREASINGLY PRONOUNCED THROUGH DAYS 6 AND 7 AS THE TROUGH APPROACHES THE E COAST STATES/ERN ATLANTIC. THE PRIMARY SEVERE THREAT DAY 4 IS PROGGED FROM E TX NEWD ACROSS THE ARKLATEX INTO THE MID MS VALLEY...AS A SHORT-WAVE TROUGH DIGS ESEWD INTO THIS REGION...WITHIN THE LARGER-SCALE TROUGH. UNSTABLE AIRMASS COMBINED WITH THE ENERGETIC SHORT-WAVE FEATURE AND ASSOCIATED/STRONG FLOW FIELD SUGGESTS WIDESPREAD SEVERE WEATHER POTENTIAL -- INCLUDING RISKS FOR LARGE HAIL...DAMAGING WINDS...AND ISOLATED TORNADOES. THE THREAT SHOULD SHIFT E OF THE MS VALLEY INTO THE MID SOUTH/SOUTHEAST DAY 5...AS THE SHORT-WAVE FEATURE TAKES ON A NEUTRAL TO EVEN NEGATIVE TILT AS IT CROSSES THIS REGION. AGAIN -- AMPLY UNSTABLE AIRMASS COMBINED WITH THE STRENGTH OF THE UPPER SYSTEM AND ASSOCIATED FLOW FIELD SUGGESTS WIDESPREAD SEVERE WEATHER CAN BE EXPECTED...INCLUDING THE POTENTIAL FOR TORNADOES. AS MODELS BEGIN DIVERGING SOMEWHAT WITH RESPECT TO TIMING AND SMALLER-SCALE DETAILS...DEGREE OF THREAT SHIFTING ACROSS THE APPALACHIANS LATE DAY 5 AND INTO DAY 6 BECOMES LESS CERTAIN. WHILE SEVERE WEATHER WILL BE LIKELY WITH THE FRONT EXPECTED TO REACH THE ATLANTIC COAST BY THE END OF THE PERIOD...WILL REFRAIN FROM HIGHLIGHTING A THREAT AREA THIS FORECAST. WITH THE FRONT LIKELY OFFSHORE BY THE START OF DAY 7... SEVERE WEATHER POTENTIAL ACROSS THE U.S. APPEARS LESS WIDESPREAD/SIGNIFICANT AND MUCH MORE UNCERTAIN THROUGH THE END OF THE PERIOD. Link to comment Share on other sites More sharing options...
WhiteoutWX Posted April 23, 2011 Share Posted April 23, 2011 Timing looks kinda crappy again for western carolinas, 12z GFS says front rolls through early-late morning, AGAIN. In fact timing is almost identical to the previous front if the GFS is right. Link to comment Share on other sites More sharing options...
FoothillsNC Posted April 23, 2011 Share Posted April 23, 2011 Timing looks kinda crappy again for western carolinas, 12z GFS says front rolls through early-late morning, AGAIN. In fact timing is almost identical to the previous front if the GFS is right. The models sometimes are too slow with squall line passages ahead of a front , esp. at this range. But for now its reasonable, but I won't be surprised to see it arrive more around midnight for western Carolinas, its just too far out to say yet. Even so, a strengthening sfc low to our northwest and neg. tilting trough will have a big punch, or could have a big punch, similar to the early April event here. Link to comment Share on other sites More sharing options...
ryan1234 Posted April 23, 2011 Share Posted April 23, 2011 The models sometimes are too slow with squall line passages ahead of a front , esp. at this range. But for now its reasonable, but I won't be surprised to see it arrive more around midnight for western Carolinas, its just too far out to say yet. Even so, a strengthening sfc low to our northwest and neg. tilting trough will have a big punch, or could have a big punch, similar to the early April event here. Any chance we will see some discrete cell development ahead of the main line? Link to comment Share on other sites More sharing options...
weatherman566 Posted April 23, 2011 Share Posted April 23, 2011 Any chance we will see some discrete cell development ahead of the main line? A little too early to say, but I believe supercellular development ahead of a squall line is very likely. Wind shear and instabilities will be very high. I really hate looking at CAPE values on models, but GFS suggests at least 1000 j/kg CAPE for GA and the western Carolinas. Strengthening area of low pressure, a large warm sector, and a strong LLJ with higher instabilities raise a flag for the entire Southeast. I think it's safe to say that ALL MODES of severe weather are likely, including supercells and a QLCS (squall line). Check out NWS Birmingham's Discussion. Very informative, unlike other offices. (not pointing a finger): THAT IS WHERE THE REAL FOCUS OF THE FORECAST WILL BEGIN. WE HAVE SEVERAL SYNOPTIC FACTORS TO BEGIN LOOKING AT THIS FAR IN ADVANCE...ONE CERTAINLY WILL BE THE UPPER DIVERGENCE/DIFFLUENCE THAT SETS UP ACROSS THE MID SOUTH BY LATE TUESDAY AND WEDNESDAY AFTERNOON. THIS WILL CAUSE RAPID PRESSURE FALLS AND A DEEPENING SURFACE LOW TO FORM...BASICALLY FROM LITTLE ROCK TO DETROIT WHILE DEEPENING 8 TO 10 MB. JUST LIKE WITH APRIL 15...THE TRACK OF THE SURFACE LOW WILL BE NEARLY SOUTH TO NORTH...WHICH SHOULD STRETCH AND EXTEND THE SOUTHEASTERN WARM SECTOR FROM THE MISSISSIPPI RIVER...EASTWARD TO THE ATLANTIC COAST BY WED AFTERNOON. IT IS NOTED THAT THE SURFACE LOW AND UPPER LEVEL DYNAMICS ARE NOT QUITE AS STRONG AT THIS JUNCTURE...HOWEVER...AS THE DEEP LAYER JET FIELDS ROUND THE BASE OF THE UPPER TROUGH AND ENTER THE WARM SECTOR...IT IS LOOKING BETTER FOR SUPERCELLS FOLLOWED BY A DECENT BROKEN SQUALL LINE. I TEND TO FOCUS ON SEVERAL ITEMS THAT COULD BE CONSIDERED SYNOPTIC TO GET SOME IDEA OF STORM MODE. FIRST IS THE 0 TO 6 KM BULK SHEAR...MAGNITUDE AND ORIENTATION. THE VECTOR ORIENTATION IS AT AN ALMOST PERFECT 45 DEGREE ANGLE WITH THE SURFACE FRONT AND INCREASING TO 55 TO 65 KTS INDICATING SUPERCELL DEVELOPMENT BETWEEN 18 AND 21Z WEDNESDAY...BUT IT DOES BACK MORE SOUTHEAST AS IT GETS CLOSER TO SUNSET...SUGGESTING THAT A SQUALL LINE IS MORE LIKELY WITH TIME OR ALONG THE FRONT. NEXT WOULD BE THE 0 TO 8 OR 10 KM BULK SHEAR...WHICH IS INDICATIVE OF LONGER TRACKED SUPERCELLS..AND IT IS AN IMPRESSIVE 75 KTS FROM 18 TO 00Z. SO THE SHEAR DOESN`T SEEM TO BE MUCH OF AN ISSUE AT THIS POINT. THE INSTABILITY IS A BIT MORE PROBLEMATIC...AS THE ARE SEVERAL CONFLICTING ARGUMENTS THAT WILL TAKE THE NEXT FEW DAYS TO SORT OUT. WE HAVE STEEP LAPSE RATES BOTH AT THE SURFACE AND ALOFT...WITH DRY AIR ALOFT TO BOOT. HOWEVER...THE 500 MB TEMPS ARE A BIT WARMER THIS GO AROUND AT -10 C...ALONG WITH A SUBSTANTIAL CAP TO WORK THROUGH FROM THE EARLY MORNING THROUGH EARLY AFTERNOON HOURS. THE CAP WILL CERTAINLY BE BREAKABLE BY THE FROPA LATER WEDNESDAY EVE/NIGHT WITH THE SQUALL LINE...HOWEVER...WE MAY HAVE A LITTLE LATER START TIME WITH THE SUPERCELLS AS UNABATED...BUFFER SOUNDINGS ARE SHOWING NEARLY 100 DEGREES. IT IS OBVIOUS WE WON`T HIT THAT BY WEDNESDAY MIDDAY...BUT THE LIFT SHOULD COMPENSATE AND THE CAP WEAKENING WITH TIME COULD ACTUALLY MAKE THE SCENARIO MUCH WORSE BY HOLDING THE ENERGY DOWN AND KEEPING THE SKIES CLOUD AND RAIN COOLED FREE EARLY ON. LOTS OF QUESTIONS AND INTERESTING THINGS TO LOOK AT AND MONITOR FROM THIS PERSPECTIVE BETWEEN NOW AND THEN. FINALLY...ONE LAST THING...AND THAT IS WHAT TO DO WITH LATE TUESDAY AFTERNOON AS THINGS FIRE UPSTREAM AND ROLL THIS WAY. INSTABILITY WILL BE HIGH LATE TUESDAY WITH LITTLE TO NO CAP DEVELOPMENT YET. HOWEVER...WAS THINKING THE SHEAR IS NOT QUITE AS GOOD...BUT DEFINITELY INCREASING WITH TIME...ESPECIALLY AFTER SUNSET...SO WE BETTER MAINTAIN VIGILANCE...BY NOT THINKING THIS WILL STRICTLY BE A WED AFTERNOON DEAL. THIS COULD BE A LOT LONGER DURATION THAN ANTICIPATED. Link to comment Share on other sites More sharing options...
LithiaWx Posted April 23, 2011 Share Posted April 23, 2011 A little too early to say, but I believe supercellular development ahead of a squall line is very likely. Wind shear and instabilities will be very high. I really hate looking at CAPE values on models, but GFS suggests at least 1000 j/kg CAPE for GA and the western Carolinas. Strengthening area of low pressure, a large warm sector, and a strong LLJ with higher instabilities raise a flag for the entire Southeast. I think it's safe to say that ALL MODES of severe weather are likely, including supercells and a QLCS (squall line). Check out NWS Birmingham's Discussion. Very informative, unlike other offices. (not pointing a finger): *cough* FFC *Cough* Link to comment Share on other sites More sharing options...
Gastonwxman Posted April 23, 2011 Share Posted April 23, 2011 Thought I share this right quick. Take a look at what the 18z NAM prints out for AR and extreme SW KY at the 84 hour. Intense band of storms rolling through those states dumping tremendous rainfall: Link to comment Share on other sites More sharing options...
ATL_Militarypolice Posted April 23, 2011 Author Share Posted April 23, 2011 Saw this posted on another forum. " Just a little info, the meteorologist on ABC National, said the upcoming outbreak could rival all so far this season....." Sent from my Droid using Tapatalk Link to comment Share on other sites More sharing options...
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