snowlover2 Posted May 31, 2014 Share Posted May 31, 2014 Could be an interesting few days ahead according to SPC and TWC. TWC Another potentially significant round of severe weather, starting in the Central Plains Tuesday and spreading into the mid-Mississippi and Ohio Valleys for Wednesday. There is the potential for squall lines packing widespread damaging winds during this time frame. It is not out of the question that a derecho -- a long-lived squall line bringing damaging winds along a path of several hundred miles -- could develop. SPC DAY 4-8 CONVECTIVE OUTLOOKNWS STORM PREDICTION CENTER NORMAN OK0400 AM CDT SAT MAY 31 2014VALID 031200Z - 081200Z...DISCUSSION...WEATHER WILL REMAIN ACTIVE THROUGH MUCH OF THE 4-8 PERIOD WITH ASERIES OF SHORTWAVE TROUGHS ADVANCING THROUGH THE LOW-AMPLITUDEPROGRESSIVE FLOW REGIME. MEANWHILE...A MEANDERING E-W FRONT WILLBECOME ESTABLISHED FROM THE CNTRL PLAINS AREA EWD INTO THE NERNSTATES AND MID ATLANTIC.TUESDAY /DAY 4/...ANOTHER IN A SERIES OF IMPULSES WILL ADVANCE INTOTHE CNTRL PLAINS AND MID-UPPER MS VALLEY REGIONS. THIS FEATURE WILLDEAMPLIFY AS IT CRESTS UPPER RIDGE BUT WILL BE ACCOMPANIED BY A 50TO 60 KT MID-LEVEL JET. MEANWHILE...WARM FRONT WILL LIFT NWD BENEATHTHE STRENGTHENING FLOW ALOFT WITH STEEP LAPSE RATES SPREADING EWDABOVE THE MOIST WARM SECTOR. POTENTIAL WILL EXIST FOR STORMS TODEVELOP ALONG AND NORTH OF THIS BOUNDARY AND EVOLVE INTO AN MCS ASTHEY DEVELOP EWD TOWARD THE MS VALLEY REGION. SUPERCELLS ANDORGANIZED BOW ECHO SYSTEMS WILL BE POSSIBLE WITHIN THE STRONGLYSHEARED AND MODERATELY TO STRONGLY UNSTABLE ENVIRONMENT. LARGE HAILAND WIDESPREAD DAMAGING WIND WILL BE POSSIBLE ALONG WITH POTENTIALFOR A FEW TORNADOES.WED /DAY 5/...THE SHORTWAVE TROUGH WILL CONTINUE EWD THROUGH THE OHVALLEY WHERE AN E-W FRONT WILL BE IN PLACE WITH A MOIST...UNSTABLEWARM SECTOR SOUTH OF THIS FEATURE ACROSS MUCH OF THE OH VALLEY. BELTOF STRONGER MID-UPPER FLOW WILL ACCOMPANY THE IMPULSE...AND STORMSWILL LIKELY REDEVELOP DURING THE DAY IN ADDITION TO POSSIBLE ONGOINGMCS TO CONTINUE. VERTICAL SHEAR FROM 35-40 KT AND A FAVORABLETHERMODYNAMIC ENVIRONMENT WILL SUPPORT POTENTIAL FOR BOTH SUPERCELLSAND ORGANIZED MCS EVENTS WITH LARGE HAIL ALONG WITH POTENTIAL FORWIDESPREAD DAMAGING WIND.BEYOND WED...PREDICTABILITY IS TOO LOW FOR AN OUTLOOK AREA AT THISTIME...BUT AN ACTIVE PATTERN WILL LIKELY CONTINUE FROM THE CNTRL ANDSRN PLAINS EWD INTO THE OH/TN VALLEY AND MID ATLANTIC DAY 6-7...DIAL.. 05/31/2014 Link to comment Share on other sites More sharing options...
OntarioChaser Posted June 1, 2014 Share Posted June 1, 2014 00 Nam wants to put a derecho right thru SW Ontario on Wednesday. Huge shift north. Looks incredible for a possible long lived event from the plains to the Atlantic coast. Link to comment Share on other sites More sharing options...
andyhb Posted June 1, 2014 Share Posted June 1, 2014 Wednesday looks like a fairly volatile setup on the GFS/Euro for the Mid MS Valley/OV, both for the potential of tornadoes and robust wind damage/possible derecho development. Link to comment Share on other sites More sharing options...
Hoosier Posted June 1, 2014 Share Posted June 1, 2014 Wednesday looks like a fairly volatile setup on the GFS/Euro for the Mid MS Valley/OV, both for the potential of tornadoes and robust wind damage/possible derecho development. I've been busy with other stuff but from what I've looked at, I'm liking the Wednesday potential. It looks like one of the more threatening setups of the year so far in this region. The setup on paper would suggest that a moderate risk could easily evolve in time. If the NAM is right then areas farther north may get involved but we know how that goes. Link to comment Share on other sites More sharing options...
snowlover2 Posted June 1, 2014 Author Share Posted June 1, 2014 New day 3 mentions possible moderate risk being needed. DAY 3 CONVECTIVE OUTLOOKNWS STORM PREDICTION CENTER NORMAN OK0230 AM CDT SUN JUN 01 2014VALID 031200Z - 041200Z...THERE IS A SLGT RISK OF SVR TSTMS FROM A PORTION OF THE NRN ANDCNTRL PLAINS INTO THE MIDDLE AND UPPER MS VALLEY......SUMMARY...NUMEROUS SEVERE STORMS ARE FORECAST TUESDAY FROM A PORTION OF THECENTRAL AND NORTHERN PLAINS INTO THE MIDDLE TO UPPER MISSISSIPPIVALLEY REGIONS. LARGE HAIL AND WIDESPREAD DAMAGING WIND APPEAR TO BETHE MAIN THREATS...BUT A FEW TORNADOES WILL ALSO BE POSSIBLE....SYNOPSIS...ACTIVE NRN STREAM WILL PERSIST TUESDAY WITH BELT OF STRONGER WLYSOVER THE NRN HALF OF THE COUNTRY. A SHORTWAVE TROUGH NOW OVER THEERN PACIFIC WILL REACH THE GREAT BASIN OR CENTRAL ROCKIES BY 12ZTUESDAY. THIS FEATURE WILL THEN RAPIDLY EJECT EWD THROUGH THE CNTRLPLAINS DURING THE DAY AND INTO THE MIDDLE TO UPPER MS VALLEY REGIONOVERNIGHT...DEAMPLIFYING IN THE PROCESS. A STRONG UPPER JET WITH60-70 KT AT 500 MB WILL ACCOMPANY THIS IMPULSE. AT THE SFC A FRONTWILL STALL FROM THE OH VALLEY WWD INTO NEB WHILE A LEE CYCLONEDEEPENS OVER THE CNTRL PLAINS IN ASSOCIATION WITH INCREASING WLYSALOFT AND FORCING ATTENDING THE EJECTING SHORTWAVE TROUGH. THISFEATURE WILL THEN SHIFT EWD ALONG THE BOUNDARY THROUGH THE CNTRLPLAINS TUESDAY NIGHT....CNTRL PLAINS THROUGH THE MID-UPPER MS VALLEY REGIONS...A FEW STORMS MAY BE ONGOING EARLY TUESDAY WITHIN ZONE OF ISENTROPICLIFT AND THETA-E ADVECTION NORTH OF WARM FRONT ACROSS NEB. RICH GULFMOISTURE WITH UPPER 60S TO NEAR 70 DEWPOINTS WILL RESIDE IN WARMSECTOR SOUTH OF THE WARM FRONT THAT WILL LIFT NWD INTO NEB DURINGTHE DAY. ONGOING CONVECTION SHOULD REINFORCE THE BAROCLINIC ZONE.MEANWHILE...PLUME OF STEEP MID-LEVEL LAPSE RATES ASSOCIATED WITH THEEML WILL ADVECT THROUGH THE CNTRL PLAINS MOIST WARM SECTOR WITHINBELT OF STRENGTHENING WLYS. THESE PROCESSES WILL CONTRIBUTE TOSTRONG INSTABILITY SOUTH OF THE FRONT /2000-3000 J/KG MLCAPE/ AS THESFC LAYER WARMS DURING THE DAY. HEIGHT FALLS AND STRENGTHENING SLYLLJ ALONG WITH BOUNDARY LAYER DESTABILIZATION SHOULD RESULT ININCREASING POTENTIAL FOR ADDITIONAL STORMS TO DEVELOP ALONG THATPORTION OF THE FRONT CLOSER TO THE WARM SECTOR. VERTICAL SHEARINCREASING TO AOA 50 KT AND STRONG INSTABILITY WILL SUPPORTORGANIZED STORMS INCLUDING SUPERCELLS WITH ANY ACTIVITY DEVELOPINGALONG THE FRONT AND NEAR TRIPLE POINT AND POSSIBLY FARTHER SOUTHALONG DRYLINE INTO WRN KS. HOWEVER...ACTIVITY SHOULD EVENTUALLY GROWUPSCALE INTO AN MCS AND IT IS ALSO POSSIBLE MORNING MCS WILL PERSISTNORTH OF THE FRONT AND BEGIN TO FORWARD PROPAGATE EWD SUSTAINED BYTHE STRENGTHENING LLJ. GIVEN THE LIKELIHOOD OF AN MCS WITHIN AFAVORABLE KINEMATIC AND THERMODYNAMIC PARAMETER SPACE...THEPOTENTIAL WILL EXIST FOR WIDESPREAD DAMAGING WIND...ESPECIALLY FROMERN NEB INTO THE MS VALLEY REGION. THIS AREA WILL CONTINUE TO BEMONITORED FOR A POSSIBLE MODERATE RISK UPGRADE IN LATER OUTLOOKS...DIAL.. 06/01/2014 Link to comment Share on other sites More sharing options...
andyhb Posted June 1, 2014 Share Posted June 1, 2014 Is Dial afraid of mentioning tornadoes in extended outlooks or is it just me? Link to comment Share on other sites More sharing options...
snowlover2 Posted June 1, 2014 Author Share Posted June 1, 2014 New day 4 outlined area. DAY 4-8 CONVECTIVE OUTLOOKNWS STORM PREDICTION CENTER NORMAN OK0400 AM CDT SUN JUN 01 2014VALID 041200Z - 091200Z...DISCUSSION...WEATHER PATTERN WILL REMAIN ACTIVE THROUGH AT LEAST DAY 6-7 WITH ASERIES OF SHORTWAVE TROUGHS ADVANCING THROUGH THE LOW-AMPLITUDEPROGRESSIVE FLOW REGIME. MEANWHILE...A MEANDERING E-W FRONT WILLBECOME ESTABLISHED FROM THE CNTRL PLAINS AREA INTO THE OH VALLEY ANDMID ATLANTIC DAY 4 AND SHIFT SWD DAY 5-6.WED /DAY 4/...LOW AMPLITUDE SHORTWAVE TROUGH WILL ADVANCE THROUGHTHE OH VALLEY AND INTERACT WITH AN E-W FRONT. A MOIST...UNSTABLEWARM SECTOR WILL EXIST SOUTH OF THIS FEATURE...AND BELT OF STRONGERMID-UPPER FLOW WILL ACCOMPANY THE SHORTWAVE TROUGH AND OVERSPREADTHE WARM SECTOR. STORMS WILL LIKELY REDEVELOP DURING THE DAY INADDITION TO POSSIBLE ONGOING MCS TO CONTINUE. VERTICAL SHEAR FROM35-40 KT AND A FAVORABLE THERMODYNAMIC ENVIRONMENT WILL SUPPORT BOTHSUPERCELLS AND ORGANIZED MCS EVENTS WITH LARGE HAIL AND THEPOTENTIAL FOR WIDESPREAD DAMAGING WIND.BEYOND DAY 4...PATTERN WILL REMAIN ACTIVE WITH FRONT SHIFTING ALITTLE FARTHER SOUTH...LIKELY EXTENDING FROM KS EWD INTO THE MIDATLANTIC DAY 5 BUT REMAINING WITHIN BELT OF MODERATE TO STRONG FLOWALOFT WHERE EMBEDDED VORTICITY MAXIMA AND LOCATION OF OUTFLOWBOUNDARIES WILL MODULATE COVERAGE OF STORMS. SEVERE STORMS WILLREMAIN LIKELY FROM THE CNTRL/SRN PLAINS EWD INTO THE MIDDLE ATLANTICDAYS 5-6. HOWEVER...IT WILL BE DIFFICULT TO DETERMINE WHERECORRIDORS OF HIGHER COVERAGE EVENTS WILL OCCUR GIVEN INFLUENCE OFONGOING CONVECTION AND UNCERTAINTY REGARDING TIMING AND AMPLITUDE OFINDIVIDUAL SHORTWAVE TROUGHS. Link to comment Share on other sites More sharing options...
IWXwx Posted June 1, 2014 Share Posted June 1, 2014 Is Dial afraid of mentioning tornadoes in extended outlooks or is it just me? I like to think that he is just focusing on the main threat this far out. Also, it looks like most offices are poo-pooing the NAM. Link to comment Share on other sites More sharing options...
Chicago Storm Posted June 1, 2014 Share Posted June 1, 2014 I like to think that he is just focusing on the main threat this far out. Also, it looks like most offices are poo-pooing the NAM.The NAM isn't the only model showing a tornado threat though. Link to comment Share on other sites More sharing options...
Powerball Posted June 1, 2014 Share Posted June 1, 2014 It's a shame the NAM's going to be wrong. Would even be a nice severe weather set-up here... Link to comment Share on other sites More sharing options...
A-L-E-K Posted June 1, 2014 Share Posted June 1, 2014 looks like a miss south but it's early in the season for us. should still get some vanilla action Link to comment Share on other sites More sharing options...
Powerball Posted June 1, 2014 Share Posted June 1, 2014 looks like a miss south but it's early in the season for us. should still get some vanilla action True. Definitely ready to see all the awesome-looking Convective Debris we get though... Link to comment Share on other sites More sharing options...
tornadotony Posted June 1, 2014 Share Posted June 1, 2014 The NAM isn't the only model showing a tornado threat though. Agreed. Haven't taken a really close look (can't afford to right now) but at first glance, there are at least some synoptic similarities to a certain day in early June 2010. Link to comment Share on other sites More sharing options...
Hoosier Posted June 1, 2014 Share Posted June 1, 2014 Agreed. Haven't taken a really close look (can't afford to right now) but at first glance, there are at least some synoptic similarities to a certain day in early June 2010. I didn't want to say it yet but since you did, there definitely are. The thermodynamic/kinematic environment is roughly similar. One thing I'm concerned about is how the early day activity evolves. June 2010 had quite a bit of clearing, or at least precip free hours, and ended up being a rather late show compared to what we're used to. Link to comment Share on other sites More sharing options...
tornadotony Posted June 1, 2014 Share Posted June 1, 2014 I didn't want to say it yet but since you did, there definitely are. The thermodynamic/kinematic environment is roughly similar. One thing I'm concerned about is how the early day activity evolves. June 2010 had quite a bit of clearing, or at least precip free hours, and ended up being a rather late show compared to what we're used to. Yeah it didn't have much clearing at all. I remember being out in La Salle County that day and it being clouded over all afternoon. Link to comment Share on other sites More sharing options...
Hoosier Posted June 1, 2014 Share Posted June 1, 2014 Yeah it didn't have much clearing at all. I remember being out in La Salle County that day and it being clouded over all afternoon. I remember having some sun late afternoon/early evening and I'm pretty sure the subject of whether there had been enough clearing to get things going came up at some point. Link to comment Share on other sites More sharing options...
AppsRunner Posted June 1, 2014 Share Posted June 1, 2014 I didn't want to say it yet but since you did, there definitely are. The thermodynamic/kinematic environment is roughly similar. One thing I'm concerned about is how the early day activity evolves. June 2010 had quite a bit of clearing, or at least precip free hours, and ended up being a rather late show compared to what we're used to. I remember having some sun late afternoon/early evening and I'm pretty sure the subject of whether there had been enough clearing to get things going came up at some point. Here in NWOH (Millbury EF-4 tornado) we had absolutely no sun during the day. I remember there was a 15 minute period before sunset where there was some broken clouds/filtered sunshine but throughout the entire day it had been completely cloudy/rainy. Link to comment Share on other sites More sharing options...
tornadotony Posted June 1, 2014 Share Posted June 1, 2014 I remember having some sun late afternoon/early evening and I'm pretty sure the subject of whether there had been enough clearing to get things going came up at some point. Yeah but the point of that is that, despite what we normally tell ourselves, that was actually a largely synoptically-driven outbreak, with supercells focusing along the pre-frontal trough and the warm front, with moderate instability, the arrival of the upper-level jet streak, and the nighttime intensification of the LLJ largely responsible for what happened. Link to comment Share on other sites More sharing options...
Hoosier Posted June 1, 2014 Share Posted June 1, 2014 Hope this works but for anyone who is interested, here is a 6 hour radar loop from 6/5/2010 from early afternoon until things were well underway in IL. https://mesonet.agron.iastate.edu/current/mcview.phtml?prod=lotrad&java=script&mode=archive&frames=37&interval=10&year=2010&month=6&day=5&hour=14&minute=0 Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 1, 2014 Share Posted June 1, 2014 I remember having some sun late afternoon/early evening and I'm pretty sure the subject of whether there had been enough clearing to get things going came up at some point. Ah what a day that was. The 12z NAM def raises some eyebrows . Link to comment Share on other sites More sharing options...
andyhb Posted June 1, 2014 Share Posted June 1, 2014 There's certainly enough low level shear on the models to cause a substantial tornado threat on Wednesday, SRH in the 250-400 m2/s2 range would be quite volatile with the amount of instability/low level moisture being shown over a broad area. Link to comment Share on other sites More sharing options...
cyclone77 Posted June 1, 2014 Share Posted June 1, 2014 Triple point and warm front area ahead of that on both the NAM and GFS look pretty nice. GFS is a little slower with the surface low. IIRC the Euro is a little slower as well. Both the NAM and GFS clear the morning precip out of the target areas early enough for substantial instability to build up. Really liking the recent model trends for Wed. Link to comment Share on other sites More sharing options...
Central Illinois Posted June 1, 2014 Share Posted June 1, 2014 Looks like the first real system of the spring to produce a major severe weather outbreak in the region Sent from my SM-G900V using Tapatalk Link to comment Share on other sites More sharing options...
Powerball Posted June 1, 2014 Share Posted June 1, 2014 DTX seems to be really bullish with the potential for convection tomorrow. We'll see... Link to comment Share on other sites More sharing options...
andyhb Posted June 1, 2014 Share Posted June 1, 2014 Excellent soundings with really nice thermodynamic profiles coming out of southern IL/IN on the 18z GFS for Wednesday, any degree of backing towards the SSW of the surface winds is really going to ramp up SRH values in a hurry. Link to comment Share on other sites More sharing options...
snowlover2 Posted June 1, 2014 Author Share Posted June 1, 2014 TWC seems a little more concerned for a derecho. Tuesday and Wednesday: A potentially significant round of severe weather, with widespread damaging winds and potentially a full-fledged derecho, affecting the Central Plains and mid-Mississippi and Ohio Valleys Link to comment Share on other sites More sharing options...
andyhb Posted June 2, 2014 Share Posted June 2, 2014 Some absolutely silly soundings (especially shear wise) on the 00z NAM for southern IA and northern MO Tuesday night into early Wednesday morning, any MCS would be absolutely full of circulations if anything like that comes to pass. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 2, 2014 Share Posted June 2, 2014 0z NAM looks like a full blown nasty MCS or derecho riding the warm front dead across IA Tuesday night and into northern IL Wed morning. Link to comment Share on other sites More sharing options...
Hoosier Posted June 2, 2014 Share Posted June 2, 2014 Doesn't look like any big changes on the 00z NAM. Seems a bit quicker than the 12z run though. Link to comment Share on other sites More sharing options...
Hoosier Posted June 2, 2014 Share Posted June 2, 2014 Some absolutely silly soundings (especially shear wise) on the 00z NAM for southern IA and northern MO Tuesday night into early Wednesday morning, any MCS would be absolutely full of circulations if anything like that comes to pass. I saw that one you posted from Nebraska. That is some video game stuff. Link to comment Share on other sites More sharing options...
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