Helicity Posted May 22, 2011 Share Posted May 22, 2011 GFS and NAM are hinting at big things on tuesday. GFS OKC sounding for tuesday at 0z. http://beta.wxcaster...&STATIONID=KOKC CAPE will be high, upper level support will be there, a strong LLJ will assert itself, all of these combining for a potent day on Tuesday and beyond. Link to comment Share on other sites More sharing options...
CUmet Posted May 22, 2011 Share Posted May 22, 2011 Tuesday is easily the most impressive setup since April 27 IMO. Link to comment Share on other sites More sharing options...
VAwxman Posted May 23, 2011 Share Posted May 23, 2011 Tuesday is easily the most impressive setup since April 27 IMO. Ugh. I don't like seeing you say that. Hopefully things will change. I have not looked too much myself but apparently I should. Link to comment Share on other sites More sharing options...
Amped Posted May 23, 2011 Share Posted May 23, 2011 It has been pretty quiet from the 29th up until yesterday. Now this looks to be a hell of a week again. The GWO is back in Phase 8, I don't know if that has anything to do with it though. Link to comment Share on other sites More sharing options...
CUmet Posted May 23, 2011 Share Posted May 23, 2011 Ugh. I don't like seeing you say that. Hopefully things will change. I have not looked too much myself but apparently I should. Well we haven't really had much in the way of any severe events since that date, so it wasn't much of a stretch. However, even after today's Joplin tragedy, I still stand by that statement. This kind of low-amplitude, progressive shortwave can cause all kinds of problems. The trough itself has some similarities to the May 10, 2010 trough. There appears to be slightly more instability over a much wider warm sector this time around, but the wind fields aren't quite as crazy. At this point, I'm leaning towards this becoming a Day 1 High Risk event. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 23, 2011 Share Posted May 23, 2011 Tuesday looks awful. Historic potential from what I have seen. Link to comment Share on other sites More sharing options...
Macintosh Posted May 23, 2011 Share Posted May 23, 2011 Tuesday looks awful. Historic potential from what I have seen. Can you list the specific States which could be impacted? Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 23, 2011 Share Posted May 23, 2011 Can you list the specific States which could be impacted? OK and southern KS are ground zero and where the CAPE/SRH/Shear combos will best located. Supers will likely erupt off the dryline late afternoon and spread east into a highly sheared environment. It really has potential to be major. Link to comment Share on other sites More sharing options...
natecast Posted May 23, 2011 Share Posted May 23, 2011 OK and southern KS are ground zero and where the CAPE/SRH/Shear combos will best located. Supers will likely erupt off the dryline late afternoon and spread east into a highly sheared environment. It really has potential to be major. I have an e-mail group I send forecasts to on a regular basis. They like my e-mails because I try not to play everything up like some of the local media do. The only time I have really used strong wording to them was during our last 2 blizzards and May 10, 2010, which was warranted. I remember 5/10/10 having insane wind fields, but Tuesday looks too have a much more volatile thermodynamic environment. Now to figure out how to relay this info to my friends and family. Link to comment Share on other sites More sharing options...
brettjrob Posted May 23, 2011 Share Posted May 23, 2011 ACUS02 KWNS 230542 SWODY2 SPC AC 230540 DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1240 AM CDT MON MAY 23 2011 VALID 241200Z - 251200Z ...THERE IS A MDT RISK OF SVR TSTMS LATE TUE AFTN INTO TUE NIGHT ACROSS CENTRAL AND EASTERN OKLAHOMA...MUCH OF CENTRAL AND EASTERN KANSAS...PARTS OF SOUTHWEST MISSOURI...NORTHWEST ARKANSAS AND NORTH CENTRAL TEXAS... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK AREA ACROSS MUCH OF THE CENTRAL PLAINS INTO THE MIDDLE MISSISSIPPI VALLEY...EASTWARD THROUGH PARTS OF THE LOWER OHIO AND TENNESSEE VALLEYS...AND NORTHEASTWARD THROUGH THE NORTHERN MID ATLANTIC COAST STATES AND HUDSON VALLEY... ...AN OUTBREAK OF SEVERE THUNDERSTORMS AND TORNADOES IS POSSIBLE LATE TUESDAY AFTERNOON AND EVENING... ..SYNOPSIS MODELS INDICATE THAT THE LARGE-SCALE TROUGH...NOW DEVELOPING INTO THE WESTERN U.S...GRADUALLY SPLITS...WITH A SIGNIFICANT SOUTHERN PORTION SLOWLY LIFTING EAST NORTHEASTWARD OUT OF THE SOUTHERN PLATEAU BY EARLY TUESDAY...AS ANOTHER LARGE AND STRONG IMPULSE APPROACHES THE PACIFIC COAST. THE LEAD TROUGH...WITH AT LEAST A COUPLE OF SIGNIFICANT EMBEDDED SMALLER SCALE IMPULSES...IS PROGGED TO EVOLVE INTO A CLOSED LOW AS IT MIGRATES ACROSS THE SOUTHERN ROCKIES INTO THE CENTRAL PLAINS LATER TUESDAY AND TUESDAY NIGHT. ASSOCIATED FORCING FOR UPWARD VERTICAL MOTION APPEARS LIKELY TO CONTRIBUTE TO FURTHER DEEPENING OF A SURFACE CYCLONE OVER THE SOUTH CENTRAL PLAINS. THIS IS EXPECTED TO BE ACCOMPANIED BY A STRENGTHENING SOUTHERLY LOW-LEVEL JET IN EXCESS OF 50 KT AT 850 MB BY EARLY TUESDAY EVENING...FROM NORTH CENTRAL TEXAS INTO EASTERN KANSAS...AS A CYCLONIC AND GENERALLY WESTERLY 70 KT 500 MB JET STREAK NOSES INTO AND THROUGH THE SOUTHERN PLAINS RED RIVER VALLEY REGION. AT THE SAME TIME...A LARGE COLD UPPER VORTEX WITH SEVERAL STRONG EMBEDDED SHORT WAVE IMPULSES WILL LINGER OVER MUCH OF EASTERN CANADA. AN ASSOCIATED SIGNIFICANT COLD FRONT APPEARS LIKELY TO ADVANCE SOUTHEAST OF THE GREAT LAKES THROUGH MUCH OF THE NORTHEAST...AS ANOTHER IMPULSE...PERHAPS CONVECTIVELY ENHANCED...WITHIN THE SOUTHERN BRANCH OF THE SPLIT UPPER FLOW...LIFTS OUT OF THE OHIO VALLEY THROUGH SOUTHERN NEW ENGLAND BY 12Z WEDNESDAY. GIVEN THE CONTINUING PRESENCE OF A SEASONABLY MOIST BOUNDARY LAYER AIR MASS IN THE WARM SECTOR OF THE PLAINS CYCLONE...AND ALONG AND AHEAD OF THE EASTERN COLD FRONT...DESTABILIZATION PROBABLY WILL BECOME SUFFICIENT TO SUPPORT CONSIDERABLE STRONG/SEVERE STORM DEVELOPMENT DURING THIS PERIOD. ASIDE FROM SOME SEA BREEZE STORMS IN THE SOUTHEAST...THIS WILL MOSTLY REMAIN WEST AND NORTH OF PERSISTENT SUBTROPICAL RIDGING CENTERED JUST EAST OF THE SOUTH ATLANTIC COAST. ..CENTRAL/SOUTHERN PLAINS LINGERING VARIABILITY AMONG THE MODELS AND ENSEMBLES CONCERNING THE TIMING AND TRACK OF THE TROUGH EMERGING FROM THE SOUTHWEST CONTINUES TO COMPLICATE THE FORECAST. BUT IT APPEARS THAT THIS WILL ONLY IMPACT THE EXACT PLACEMENT OF THE HIGHEST SEVERE PROBABILITIES...AS THE EVOLVING LARGE-SCALE PATTERN SEEMS SUPPORTIVE OF A FAIRLY CLASSIC SEVERE WEATHER OUTBREAK. AND ENOUGH COMMON GROUND APPEARS TO EXIST TO JUSTIFY AN UPGRADE TO MODERATE RISK SEVERE PROBABILITIES ACROSS MUCH OF CENTRAL/EASTERN KANSAS AND OKLAHOMA...PORTIONS OF NORTH CENTRAL TEXAS...NORTHWEST ARKANSAS AND SOUTHWEST MISSOURI. SURFACE DEW POINTS AROUND 70F ARE PROGGED IN THE WARM SECTOR OF THE DEEPENING CYCLONE...ALONG AND EAST OF A SHARPENING DRY LINE DURING THE LATE AFTERNOON HOURS...WHEN PEAK AFTERNOON HEATING AND STEEPENING LAPSE RATES ASSOCIATED WITH MID-LEVEL COOLING PROBABLY WILL CONTRIBUTE TO MIXED LAYER CAPE OF 2000-4000 J/KG. AS THE MID-LEVEL JET NOSES INTO THE RED RIVER VALLEY...THE DRY LINE IS EXPECTED TO BECOME THE FOCUS FOR THE PRIMARY STORM DEVELOPMENT AS IT SURGES NORTHEASTWARD OUT OF SOUTH CENTRAL KANSAS...AND EASTWARD OUT OF CENTRAL OKLAHOMA...THROUGH MUCH OF EASTERN KANSAS AND OKLAHOMA BY LATE EVENING. GIVEN THE ANTICIPATED WIND PROFILES...EXHIBITING STRONG DEEP LAYER SHEAR AND LARGE CLOCKWISE CURVED LOW-LEVEL HODOGRAPHS...THE ENVIRONMENT IS EXPECTED TO BECOME CONDUCIVE TO LONG-LIVED SUPERCELLS CAPABLE OF PRODUCING VERY LARGE HAIL AND STRONG TORNADOES. THIS THREAT MAY CONTINUE THROUGH MUCH OF THE EVENING...PERHAPS INTO THE 06-09Z TIME FRAME...GRADUALLY SPREADING TOWARD THE LOWER MISSOURI VALLEY AND OZARKS...BEFORE DIMINISHING IN THE PRESENCE OF A MORE STABLE OR STABILIZING BOUNDARY LAYER. ..NORTHERN MID ATLANTIC STATES INTO THE LOWER HUDSON VALLEY WEAK TO MODERATE DESTABILIZATION ALONG AND AHEAD OF THE SOUTHEASTWARD ADVANCING COLD FRONT...AND WITHIN THE PRE-FRONTAL LEE SURFACE TROUGH...IS EXPECTED TO PROVIDE THE FOCUS FOR VIGOROUS CONVECTIVE DEVELOPMENT WITH THE APPROACHING UPPER IMPULSE TUESDAY AFTERNOON. MODELS ARE A BIT MORE UNCLEAR CONCERNING THE STRENGTH OF THE VERTICAL SHEAR...BUT IT SHOULD BE ENOUGH TO SUPPORT POTENTIAL FOR ORGANIZED STORM CLUSTERS...AND ISOLATED SUPERCELLS MAY NOT BE OUT OF THE QUESTION. THIS COULD IMPACT MUCH OF THE URBAN CORRIDOR...FROM WASHINGTON D.C./BALTIMORE TO NEW YORK CITY...BEFORE CONVECTION DIMINISHING/SPREADS OFFSHORE WITH UPPER FORCING BY TUESDAY EVENING. ..KERR.. 05/23/2011 Link to comment Share on other sites More sharing options...
ksstormhunter Posted May 23, 2011 Share Posted May 23, 2011 Just pushed out a target area forecast for tommorrow based on my Smart Model output. Tracking the highest areas running from a Tulsa to Ponca City to Oklahoma City to McAlester to Fort Smith, AR. Then a second area running from Wichita to Blue Mound to Independence, KS. Again very good instability across all the the Midwest, just pinning down the highest areas. Potential for numerous EF2, Isolated EF3 type Tornadoes, Convective Gusts up to 80 knots, and hail up to 3" diameter. Thoughts? Link to comment Share on other sites More sharing options...
ICEHOCEY77 Posted May 23, 2011 Share Posted May 23, 2011 wow. 0z-06z tues on the NAM/GFS is ridiculous. SREF takes it a bit higher than the others. Link to comment Share on other sites More sharing options...
Stebo Posted May 23, 2011 Share Posted May 23, 2011 wow. 0z-06z tues on the NAM/GFS is ridiculous. SREF takes it a bit higher than the others. SREF really going gangbusters on the Warm Front on Tuesday. Oh and looking at Wednesday with the SREF I think the Day 3 will be worded strongly Link to comment Share on other sites More sharing options...
Crazieman Posted May 23, 2011 Share Posted May 23, 2011 ICT weighs in TUES:SOME MODEL DIFFERENCES IN THE WIND FIELDS FOR TUESDAY BETWEEN THE GFS AND NAM/WRF...BUT BOTH MODELS SHOW A STRONG MID LEVEL SHORTWAVE PUSHING INTO THE PLAINS FOR TUE AFTN. SFC DIFFERENCES WILL MAINLY AFFECT THE PLACEMENT OF THE BEST SEVERE WEATHER CHANCE ON THIS DAY...AS UNSTABLE AIRMASS WILL BE IN PLACE...AS 0-8KM SHEAR INCREASES TO 60-80KTS BY TUE AFTERNOON. FOCUS OF CONVECTIVE DEVELOPMENT WILL BE ALONG A DRYLINE EXPECTED TO SHARPEN ACROSS WRN SECTIONS OF THE COUNTY WARNING AREA...AS THE MAIN SFC LOW DEEPENS OVER SW KS AND LIFTS TO THE NORTHEAST. ALL SIGNS ARE BEGINNING TO COME TOGETHER FOR AN OUTBREAK OF SEVERE WEATHER FOR THE AREA FOR TUE EVENING. FORECAST SOUNDINGS SUGGEST AREA WILL BE CAPPED FOR A GOOD PORTION OF THE DAYTIME HOURS...BUT THE SIGNIFICANT SHORTWAVE WILL WEAKEN THIS CAP ENOUGH FOR WIDESPREAD SUPERCELL DEVELOPMENT TUE EVENING. WILL HAVE TO KEEP AN EYE ON THIS...AS 0-8KM SHEAR AND DIRECTIONAL SHEAR SUGGESTS A CHANCE FOR LONG TRACK SUPERCELLS AND POSSIBLE TORNADOES. STAY TUNED. Link to comment Share on other sites More sharing options...
Helicity Posted May 23, 2011 Author Share Posted May 23, 2011 This does look dangerous Link to comment Share on other sites More sharing options...
CUmet Posted May 23, 2011 Share Posted May 23, 2011 This has major tornado outbreak stamped all over it, and my confidence is high that this will end up being a High Risk. One of the most classic setups you can draw up for the Southern Plains. A low-amplitude wave with an associated mid-level jet streak of 60+ kt slams into an extremely unstable warm sector, with the LLJ intensifying during the late afternoon and early evening hours. I vaguely remember a time when I used to get excited about such things... Link to comment Share on other sites More sharing options...
Macintosh Posted May 23, 2011 Share Posted May 23, 2011 This has major tornado outbreak stamped all over it, and my confidence is high that this will end up being a High Risk. One of the most classic setups you can draw up for the Southern Plains. A low-amplitude wave with an associated mid-level jet streak of 60+ kt slams into an extremely unstable warm sector, with the LLJ intensifying during the late afternoon and early evening hours. I vaguely remember a time when I used to get excited about such things... Even as a weather enthusiast, I'm tired. Tired of the massive destructive tornado hits to population centers. It's not fun seeing this. At least with a hurricane you have advance warning. Tornadoes are difficult to deal with, before, during, and after. Link to comment Share on other sites More sharing options...
Ed Lizard Posted May 23, 2011 Share Posted May 23, 2011 Just going by last set of SREFs (new short ensembles coming out now) looks bad in Kansas. Link to comment Share on other sites More sharing options...
Ian Posted May 23, 2011 Share Posted May 23, 2011 I guess you guys can thank us for kicking that crap blocking pattern over the U.S. by returning east. Link to comment Share on other sites More sharing options...
brettjrob Posted May 23, 2011 Share Posted May 23, 2011 With the apparent trend toward a sharper and more negative-tilt shortwave for tomorrow (May 24), directional shear seems just a bit less than ideal over parts of the dryline. I fully expect a significant event, but the latitudinal extent of long-track tornadic supercells could possibly be limited by this factor, IMO. Right now, I like a 50-75 mi. radius around ICT for the best chance of something truly high-end, based upon the more backed low-level flow depicted on the GFS/NAM (compared with the OKC area). Link to comment Share on other sites More sharing options...
Hoosier Posted May 23, 2011 Share Posted May 23, 2011 SREF really going gangbusters on the Warm Front on Tuesday. Oh and looking at Wednesday with the SREF I think the Day 3 will be worded strongly I don't like seeing numbers that high this far out. Link to comment Share on other sites More sharing options...
Ed Lizard Posted May 23, 2011 Share Posted May 23, 2011 With the apparent trend toward a sharper and more negative-tilt shortwave for tomorrow (May 24), directional shear seems just a bit less than ideal over parts of the dryline. I fully expect a significant event, but the latitudinal extent of long-track tornadic supercells could possibly be limited by this factor, IMO. Right now, I like a 50-75 mi. radius around ICT for the best chance of something truly high-end, based upon the more backed low-level flow depicted on the GFS/NAM (compared with the OKC area). I think late May, good moisture return, steep lapse rates approaching dry (I saw a mention, maybe FWD's disco about near 9ºC/Kg) and temps well into the 80s and 90s, the less than ideal shear, more often found in May, may be balanced by high instability. I can think of a late season Texas outbreak that included an F-5 that had modest shear but very, very high CAPE. On second thought, GFS OKC sounding for tomorrow, the only negative for huge tornadoes is a fairly high LCL. But EHI of 10? No shortage of helicity there if correct. Link to comment Share on other sites More sharing options...
brettjrob Posted May 23, 2011 Share Posted May 23, 2011 I think late May, good moisture return, steep lapse rates approaching dry (I saw a mention, maybe FWD's disco about near 9ºC/Kg) and temps well into the 80s and 90s, the less than ideal shear, more often found in May, may be balanced by high instability. I can think of a late season Texas outbreak that included an F-5 that had modest shear but very, very high CAPE. I agree, and as I said before, I expect a significant event with at least a fair number of tornadoes. Just trying to pin down the area most at risk for more of a "once in years" type outcome. On second thought, GFS OKC sounding for tomorrow, the only negative for huge tornadoes is a fairly high LCL. But EHI of 10? No shortage of helicity there if correct. Yeah; there's not much to nitpick about on that sounding besides the cap, which is not really a concern given the forcing that will arrive by tomorrow evening. An LCL height in the 800 m range is plenty low enough for significant tornadoes. It is worth mentioning that an ideal hodograph for areas along and W of I-35 features more backed 850 mb winds, such that shear in the lowest 1.5 km is almost entirely of the speed variety (rather than directional). Still, SSW flow at 850 mb has not precluded significant high-CAPE events like 2010-05-10 or 2003-05-08 in the OKC area. Link to comment Share on other sites More sharing options...
thewxmann Posted May 23, 2011 Share Posted May 23, 2011 I'm a little concerned about moisture mixing out south of I-40. Otherwise, it looks like a strong cap strong forcing day, similar to 5/10/10. Forecast soundings out of southern KS look absolutely incredible right now. edit: A little concerned about possibility that convection initiates early (lets say 20-21Z) in a weak low-level shear environment and storm mode goes bonkers. We'll see. Link to comment Share on other sites More sharing options...
blackjack123 Posted May 23, 2011 Share Posted May 23, 2011 Strong wording DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1216 PM CDT MON MAY 23 2011 VALID 241200Z - 251200Z ...THERE IS A MDT RISK OF SVR TSTMS FROM NWRN TX TO SRN NEB... ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK OVER THE SRN/CNTRL PLAINS THROUGH THE OH/TN VALLEY TO SRN NY... ...TORNADIC OUTBREAK POSSIBLE ACROSS THE CENTRAL AND SOUTHERN PLAINS TUESDAY. AN UPGRADE TO HIGH RISK MAY BE WARRANTED AS SITUATION BECOMES MORE CERTAIN... A CLASSIC PLAINS TORNADIC OUTBREAK APPEARS TO BE EVOLVING ACROSS THE CNTRL/SRN PLAINS...ESPECIALLY FOR KANSAS AND OKLAHOMA. LATEST MODEL GUIDANCE IS CONSISTENT REGARDING THE PROGRESSION OF A VERY STRONG MID LEVEL SHORTWAVE TROUGH...CURRENTLY DIGGING ESEWD ACROSS SRN CA...INTO THE SWRN U.S./SRN ROCKIES BEFORE EJECTING INTO THE PLAINS BY PEAK HEATING. A VERY DIFFLUENT UPPER FLOW REGIME WILL OVERSPREAD THE PLAINS AS 30-60M 12HR HEIGHT FALLS EDGE EWD. ADDITIONALLY...H5 SPEED MAX APPROACHING 80-90KT...AS NOTED IN THE GFS...WILL RACE TO A POSITION OVER NWRN TX/SWRN OK BY 25/00Z WHICH WILL GENERATE VERY STRONG SHEAR ACROSS THE WARM SECTOR FOR AREAS NEAR THE RED RIVER REGION...NWD INTO KS AND EVEN SRN NEB. NEEDLESS TO SAY A VERY DYNAMIC SHORTWAVE TROUGH SHOULD TIME FAVORABLY FOR RAPID SEVERE THUNDERSTORM INITIATION ALONG/AHEAD OF THE DRYLINE AS ATMOSPHERIC HEATING IS MAXIMIZED. I am right in the middle of it all. I am starting to almost hate tornadoes. It seems like history keeps repeating itself this year as deadly tornadoes strike large cities. Link to comment Share on other sites More sharing options...
Helicity Posted May 23, 2011 Author Share Posted May 23, 2011 Jeez that Day 2 outlook has some seriously strong wording. Link to comment Share on other sites More sharing options...
Helicity Posted May 23, 2011 Author Share Posted May 23, 2011 Shallow moisture might be a concern somewhere. Link to comment Share on other sites More sharing options...
Fred Gossage Posted May 23, 2011 Share Posted May 23, 2011 I'm a little concerned about moisture mixing out south of I-40. Otherwise, it looks like a strong cap strong forcing day, similar to 5/10/10. Forecast soundings out of southern KS look absolutely incredible right now. edit: A little concerned about possibility that convection initiates early (lets say 20-21Z) in a weak low-level shear environment and storm mode goes bonkers. We'll see. I'd be very careful taking these wind profiles at face value though. If we would've done that for 4/27... as late as the 12Z NAM the day of the outbreak, we would've been expecting 0-1 km SRH over Alabama to remain under 250 m2/s2 during peak heating. This bias in the NAM and GFS seems to be one of the most persistent biases that they both have. Use extreme caution with this... Link to comment Share on other sites More sharing options...
beneficii Posted May 23, 2011 Share Posted May 23, 2011 I'd be very careful taking these wind profiles at face value though. If we would've done that for 4/27... as late as the 12Z NAM the day of the outbreak, we would've been expecting 0-1 km SRH over Alabama to remain under 250 m2/s2 during peak heating. This bias in the NAM and GFS seems to be one of the most persistent biases that they both have. Use extreme caution with this... The NAM and GFS have a tendency to underdo low-level helicity? Link to comment Share on other sites More sharing options...
Fred Gossage Posted May 23, 2011 Share Posted May 23, 2011 The NAM and GFS have a tendency to underdo low-level helicity? They have since at least 3/28/07, if not before. We've had several several big events with underforecasted wind profiles until right at the very last minute. Link to comment Share on other sites More sharing options...
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