andyhb Posted April 13, 2012 Author Share Posted April 13, 2012 Those are much higher values than what showed up on the 00z run... Link to comment Share on other sites More sharing options...
SkylerP Posted April 13, 2012 Share Posted April 13, 2012 What's with that pink blob over Texas? Link to comment Share on other sites More sharing options...
andyhb Posted April 13, 2012 Author Share Posted April 13, 2012 What's with that pink blob over Texas? 0-3 km EHI (Energy Helicity Index, which multiplies CAPE by helicity and then divides the result by 160,000) in excess of 6 (which is very high) although that area will likely remain capped tomorrow. Link to comment Share on other sites More sharing options...
JoMo Posted April 13, 2012 Share Posted April 13, 2012 If the sim reflectivity is right (and that's a really huge if) there will be storms that are located near or over an area with EHI of 7.0 with no CIN and low LCL's at 03z this evening near OKC and points west. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted April 13, 2012 Share Posted April 13, 2012 06Z NAM is slower and slightly weaker Saturday. I mainly don't care because it is the NAM. Link to comment Share on other sites More sharing options...
JoMo Posted April 13, 2012 Share Posted April 13, 2012 Wichita had a pretty great AFD this morning: http://www.wunderground.com/DisplayDisc.asp?DiscussionCode=ICT&StateCode=KS&SafeCityName=Wichita Link to comment Share on other sites More sharing options...
David Reimer Posted April 13, 2012 Share Posted April 13, 2012 Wichita had a pretty great AFD this morning: http://www.wundergro...ityName=Wichita I'll post it here for archiving purposes... Area forecast discussion National Weather Service Wichita Kansas 326 am CDT Friday Apr 13 2012 Discussion... Main forecast concerns will be chances of severe storms this evening/overnight across southern Kansas. Then a more significant threat of a tornado outbreak for late Sat afternoon/evening for the entire forecast area. Today-tonight: current impulse that led to the showers/storms across cen Kansas...continues to make progress across northern Kansas this morning. As this impulse moves northeast...expect shower chances to push east as well as warm advection veers to the east. This impulse will also lead to weak ridging and somewhat drier air pulling into portions of cen Kansas early today...with the dry line actually taking more of NE to SW look for the early portion of the day...before stalling along the Kansas Turnpike...or possibly just northwest of the Turnpike. How far this boundary pushes southeast is uncertain...but also critical for storm chances for the late afternoon hours. This dry line looks to retreat back to the northwest during the late afternoon/evening hours...with low level moisture increasing across portions of south central Kansas basically back northwest of the Kansas Turnpike. A little uncertain on how convection chances will play out for this afternoon as convergence isnt very good along the boundary and widespread middle level forcing looks lacking. Areas SW of kict into northern OK looks like the most likely region for convection to develop towards 00z/Sat...as the low level jet increases over the top of diffluent flow aloft. As this warn advection increases across northern OK...a moderately unstable airmass will be in place...with MLCAPE values of 1700-2000 j/kg and bulk shear values of 45 kts. This suggests a few discrete supercells could develop along or just south of the Kansas/OK border...and make their way east/northeast into the southern row of counties south and southeast of kict. Main concern with the supercells across southern Kansas appears to be large hail...as better 0-1km storm relative helicity values for a tornado threat remains south of the Kansas/OK border. The severe threat looks to spread north and northeast and continue for the late evening/overnight hours as the most unstable cape values actually increase across most of southern and southeast Kansas into the am hours on Sat. So could see the severe weather linger into the early morning hours on Sat...especially for areas east of the Turnpike. Sat: could see some lingering showers/thunderstorms across the area for the morning hours on Sat...as the low level jet/warm advection continue over most of the eastern half of the forecast area. But expect this convection to move off to the east-northeast by middle morning on Sat. Once the morning convection ends...focus will quickly shift to a significant severe weather event across the forecast area for Sat afternoon/evening as the dryline is expected to set up along a line from khys to near kp28. A combination of moderate to high instability is forecast just ahead of this dryline from ksln to kict with MLCAPE values expected in the 2000 to 3000 j/kg range. Bulk shear values of 70 kts...perpendicular to the dryline and 0-1 km storm relative helicity values of 400-500 m2/s2 suggest large looping hodographs...which looks ideal for supercell thunderstorms and strong/long track tornadoes. Both the NAM and GFS are having some trouble developing widespread convection along this boundary until middle level lift increases towards 00z/Sat...with coverage expected to be more scattered in nature until then. With this said...NAM/WRF forecast sounding for kict at 03z/Sat looks like the proverbial "loaded gun"...with supercells and a few strong tornadoes looking very likely Sat evening from ksln to kict. Current indications suggest that a large portion of the forecast could see a tornado outbreak Sat evening. A large concern exists that the tornado threat will continue into the hours after sunset Sat evening...as MLCAPE values remain high and cin values remain low with boundary layer moisture remaining high. This would keep the supercell thunderstorms rooted in the boundary layer...increasing the chance for a long track tornado continuing long after dark. Studies have shown that tornadoes after dark significantly increase the potential for loss of life. Storm Prediction Center coordinated with the local offices and they have gone with a rare day2 high risk across the area. Link to comment Share on other sites More sharing options...
phlwx Posted April 13, 2012 Share Posted April 13, 2012 Just my personal opinion but this has a bust potential written on it. Just doesn't give me much confidence that the 12z and 0z nam and gfs haven't come into better agreement over time. But since I said this I jinxed myself so plan on another epic outbreak Might be the kind of day where the storm/tornado count is "relatively" low but you get a couple of nasty long-tracks that do quite a bit of damage and "make up" for a relatively low tornado count. Modeling should give some pause...not on the parameter side but on storms not firing until late, late Saturday night/early Sunday morning. Link to comment Share on other sites More sharing options...
Indystorm Posted April 13, 2012 Share Posted April 13, 2012 AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 331 AM CDT FRI APR 13 2012 .DISCUSSION... NEARLY ALL OF THE CHANGING WEATHER WILL OCCUR THIS WEEKEND ALLOWING NEXT WEEK TO BE RATHER TRANQUIL AND WARM WITH LITTLE CHANCE FOR RAIN. IN THE MEAN TIME, A SIGNIFICANT SEVERE WEATHER EPISODE IS TAKING FORM FOR LATE SATURDAY IN WESTERN AND CENTRAL OKLAHOMA. BEFORE THEN, MOISTURE WILL CONTINUE ITS INCREASE TODAY AND SHOWERS AND THUNDERSTORMS MAY OCCUR NEAR A DRYLINE WHICH IS EXPECTED TO ENTER NORTHWEST OKLAHOMA LATE THIS AFTERNOON. ANY STORMS WHICH FORM WILL LIKELY BECOME SUPERCELLS AND MOVE QUICKLY NORTHEAST. THERE IS A TORNADO AND LARGE HAIL THREAT. ON SATURDAY, AS THE LARGE-SCALE UPPER WAVE APPROACHES THE SHEAR WILL BE STRONGER STILL AND THE DRYLINE IS EXPECTED TO BE ORIENTED MORE NORTH-SOUTH AS IT MOVES ACROSS THE LARGER WESTERN BORDER OF OKLAHOMA EARLY IN THE EVENING. SEVERE WEATHER INCLUDING TORNADOES AND GIANT HAIL IS EXPECTED TO HAVE A LARGE COVERAGE FROM OKLHAOMA CITY NORTH. COVERAGE IS EXPECTED TO BE LESS IN WESTERN AND SOUTHERN OKLAHOMA, BUT THE SEVERE RISK REMAINS HIGH. KOUN finally mentions tornadoes. Guess they figure many in their area turn to SPC outlooks. Link to comment Share on other sites More sharing options...
SmokeEater Posted April 13, 2012 Share Posted April 13, 2012 From National Weather Service Chicago: THE MAIN FEATURE OF CONCERN IS A VERY LARGE AND VERY DEEP CLOSED UPPER LOW SPINNING JUST OFF THE CALIFORNIA/OREGON/WASHINGTON COASTS. OF NOTE...LIGHTNING HAS OCCURRED ACROSS CENTRAL/NORTHERN CALIFORNIA WHICH IS DISCONCERTING AS SUCH AN OCCURRENCE OFTEN PRECEDES SIGNIFICANT/HIGH IMPACT WEATHER ACROSS THE MIDWEST. Link to comment Share on other sites More sharing options...
Superstorm93 Posted April 13, 2012 Share Posted April 13, 2012 It's going to be an interesting day watching the models. Hopefully this calms down a bit. Link to comment Share on other sites More sharing options...
Superstorm93 Posted April 13, 2012 Share Posted April 13, 2012 Very impressive system Link to comment Share on other sites More sharing options...
SmokeEater Posted April 13, 2012 Share Posted April 13, 2012 Oh boy, valid at 03z tonight. Bullseye OKC. Link to comment Share on other sites More sharing options...
SmokeEater Posted April 13, 2012 Share Posted April 13, 2012 If things get really rolling today, and obviously tomorrow, can we make threads for each day, as this one will get massive? Link to comment Share on other sites More sharing options...
thewxmann Posted April 13, 2012 Share Posted April 13, 2012 From National Weather Service Chicago: THE MAIN FEATURE OF CONCERN IS A VERY LARGE AND VERY DEEP CLOSED UPPER LOW SPINNING JUST OFF THE CALIFORNIA/OREGON/WASHINGTON COASTS. OF NOTE...LIGHTNING HAS OCCURRED ACROSS CENTRAL/NORTHERN CALIFORNIA WHICH IS DISCONCERTING AS SUCH AN OCCURRENCE OFTEN PRECEDES SIGNIFICANT/HIGH IMPACT WEATHER ACROSS THE MIDWEST. I can personally verify this. This has probably been the most electrified storm I've experienced since March 9-11, 2006. Link to comment Share on other sites More sharing options...
Stebo Posted April 13, 2012 Share Posted April 13, 2012 I can personally verify this. This has probably been the most electrified storm I've experienced since March 9-11, 2006. Yeah that map Superstorm posted is pretty surprising, that is your dynamics for this storm doing work over California Link to comment Share on other sites More sharing options...
thewxmann Posted April 13, 2012 Share Posted April 13, 2012 First severe warning from this system SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE OXNARD CA 443 AM PDT FRI APR 13 2012 CAC079-131215- /O.CON.KLOX.SV.W.0001.000000T0000Z-120413T1215Z/ SAN LUIS OBISPO CA- 443 AM PDT FRI APR 13 2012 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 AM PDT FOR WESTERN SAN LUIS OBISPO COUNTY... AT 429 AM PDT...VANDENBERG DOPPLER RADAR CONTINUED TO INDICATE A LINE OF THUNDERSTORMS FROM PASO ROBLES TO PISMO BEACH AND ACROSS THE ADJACENT COASTAL WATERS. DUAL POL RADAR CONTINUED TO INDICATE SOME ROTATING CELLS WITHIN THIS BAND. STORMS WERE MOVING EAST NORTHEAST AT 30 MPH. Link to comment Share on other sites More sharing options...
Superstorm93 Posted April 13, 2012 Share Posted April 13, 2012 That's really interesting that you have rotating cells in CA "DUAL POL RADAR CONTINUED TO INDICATE SOME ROTATING CELLS WITHIN THIS BAND. STORMS WERE MOVING EAST NORTHEAST AT 30 MPH. " Link to comment Share on other sites More sharing options...
Derecho! Posted April 13, 2012 Share Posted April 13, 2012 New Day 1 is out, they Hatched Oklahoma...long and complicated discussion, concerned both about early convection and then initiation tonight. Link to comment Share on other sites More sharing options...
OceanStWx Posted April 13, 2012 Share Posted April 13, 2012 Is there some sort of record for the significant tornado parameter? (STP) I think I saw STP=10 last year on April 27th. There definitely should be some unbelievable shear/helicity values somewhere in the middle of the risk area, with CAPE around 2000. Off the top of my head I can't remember the 19/00z sounding from June 2009 at DVN parameter, but I know it was in excess of 20. Considering it's a calculation of CAPE, 0-1 km helicity, magnitude of 0-6 km shear, and LCL height any extreme CAPE, strong shear event will feature some massive values. This is why it is a good idea to monitor the new SPC effective parameters, especially in capped situations. Link to comment Share on other sites More sharing options...
NaoPos Posted April 13, 2012 Share Posted April 13, 2012 I think the best thing to do would start an obs thread sat morning either in here on on the main forum. Link to comment Share on other sites More sharing options...
wxmeddler Posted April 13, 2012 Share Posted April 13, 2012 I think the best thing to do would start an obs thread sat morning either in here on on the main forum. If things start to get crazy today then we should probally create a obs thread for that too and leave this for synoptic scale and model dissussion. Link to comment Share on other sites More sharing options...
ilstormchaser Posted April 13, 2012 Share Posted April 13, 2012 I have been watching things closely the last several days and I will be chasing this event. Will decide in the morning but right now am thinking about chasing Eastern Nebraska on Saturday unless that area is socked in with morning precip. The dryline looks great of course but the NAM attm is indicating stuff not firing until around 7-8 pm or so. After 7 pm when the really strong 850 mb winds kick in things will go crazy over Eastern KS no question at this point. Storms over Eastern Nebraska should have a better chance of developing during the daytime hours. If I did decide to go to Eastern NE that would put me in a much better posistion for Sunday across Eastern Iowa into Northern IL and Southern WI as it appears stuff may fire during the early afternoon. This area has to be watch carefully and am thinking that SPC may be underestimating the potential on Sunday. Granted I will need some rockets strapped to my car for Sunday to keep up with the storms. Link to comment Share on other sites More sharing options...
scoresman Posted April 13, 2012 Share Posted April 13, 2012 Plan on chasing Saturday (along with a thousand others I bet) but worried that initiation will not start until after dark. Just about every run I have seen shows the "at dusk" start of the storm but several chasers I know are expecting storms (and tor watches) to start around noon....... Either way everybody be safe out there. Im more worried about traffic jams/accidents then the storms to be honest. Link to comment Share on other sites More sharing options...
ICEHOCEY77 Posted April 13, 2012 Share Posted April 13, 2012 Right around Lawton, OK looks to be the sweet spot for this afternoon/evening. Although the new NAM is trying to shift things to the west. On an aside, what is being done for tomorrow? Are we going to keep a thread in here as well as the main board? I'd like to keep the weenieism to a minimum in at least one thread. Link to comment Share on other sites More sharing options...
Jim Martin Posted April 13, 2012 Share Posted April 13, 2012 06z NAM Sounding for Wichita, Kansas valid at 1am cdt Sunday morning. Link to comment Share on other sites More sharing options...
Disc Posted April 13, 2012 Share Posted April 13, 2012 On an aside, what is being done for tomorrow? Are we going to keep a thread in here as well as the main board? I'd like to keep the weenieism to a minimum in at least one thread. I'd also like to know if there will be a second thread for radar images and real-time updates and another thread for actual analysis of the event itself. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted April 13, 2012 Share Posted April 13, 2012 The extremely late initiation with such a dynamic setup at 500mb to the west and the fact its only mid-April surprises me a bit...even with the surface low being way up in NE I'm not so sure we won't see development closer to 4 or 5pm in KS/OK on Saturday even though the models currently say no. Link to comment Share on other sites More sharing options...
B-Rent Posted April 13, 2012 Share Posted April 13, 2012 I'd also like to know if there will be a second thread for radar images and real-time updates and another thread for actual analysis of the event itself. Right around Lawton, OK looks to be the sweet spot for this afternoon/evening. Although the new NAM is trying to shift things to the west. On an aside, what is being done for tomorrow? Are we going to keep a thread in here as well as the main board? I'd like to keep the weenieism to a minimum in at least one thread. If things start to get crazy today then we should probally create a obs thread for that too and leave this for synoptic scale and model dissussion. How many threads are there going to be? There is already 2 1/2. One in C/W, one in Wx, and GLOV counts as half, since this system will be affecting us. I am all for separating the content, but there comes a point where you lose the discussion because no one knows where to post. Link to comment Share on other sites More sharing options...
soonertrey Posted April 13, 2012 Share Posted April 13, 2012 I have been watching things closely the last several days and I will be chasing this event. Will decide in the morning but right now am thinking about chasing Eastern Nebraska on Saturday unless that area is socked in with morning precip. The dryline looks great of course but the NAM attm is indicating stuff not firing until around 7-8 pm or so. After 7 pm when the really strong 850 mb winds kick in things will go crazy over Eastern KS no question at this point. Storms over Eastern Nebraska should have a better chance of developing during the daytime hours. If I did decide to go to Eastern NE that would put me in a much better posistion for Sunday across Eastern Iowa into Northern IL and Southern WI as it appears stuff may fire during the early afternoon. This area has to be watch carefully and am thinking that SPC may be underestimating the potential on Sunday. Granted I will need some rockets strapped to my car for Sunday to keep up with the storms. It will be interesting to see what time the dryline fires. I'm not sure that I'm buying the NAM right now on that. Link to comment Share on other sites More sharing options...
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