CUmet Posted April 10, 2011 Share Posted April 10, 2011 I might be missing something but with moderate instability, modest directional shear, good speed shear, and lack of linear forcing early on, why wouldn't there be supercellular structures around S WI/N IL with anything that can fire in the early evening? Unless you meant multiple tornadic cells which is more debatable. Yeah I meant tornadic. Link to comment Share on other sites More sharing options...
Indystorm Posted April 10, 2011 Share Posted April 10, 2011 CINH is -50 to -100 in eastern IA, western WI. per SPC meso page. Link to comment Share on other sites More sharing options...
janetjanet998 Posted April 10, 2011 Author Share Posted April 10, 2011 MESOSCALE DISCUSSION 0396 NWS STORM PREDICTION CENTER NORMAN OK 0130 PM CDT SUN APR 10 2011 AREAS AFFECTED...EXTREME SERN MN...NERN IA...NWRN IL AND MUCH OF WI CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY VALID 101830Z - 102030Z OUTBREAK OF SEVERE STORMS IS EXPECTED THIS AFTERNOON...INITIALLY FROM ERN MN THROUGH NERN IA...THEN SPREADING RAPIDLY EWD THROUGH WI AND EXTREME NWRN IL. SUPERCELLS WITH STRONG TORNADOES...VERY LARGE HAIL AND DAMAGING WIND WILL BE THE MAIN THREATS. A TORNADO WATCH WILL LIKELY BE ISSUED BY 20Z. THIS AFTERNOON A COLD FRONT EXTENDS FROM A DEEP LOW PRESSURE AREA IN E-CNTRL MN SSWWD THROUGH SRN MN...NWRN IA INTO SERN NEB WITH A WARM FRONT FROM THE SURFACE LOW IN E-CNTRL MN THROUGH NRN WI. THE LOW WILL DEVELOP EWD TO NEAR THE WI BORDER BY 21Z. NEWD ADVECTION OF HIGHER THETA-E AIR ALONG A STRONG SSWLY LLJ BENEATH EML PLUME /8.5 C/KM LAPSE RATES/ AND DIABATIC WARMING IS RESULTING IN NEWD DESTABILIZATION WITH TIME. HOWEVER...THE BOUNDARY LAYER REMAINS CAPPED BY THE WARM EML AS EVIDENCED BY 18Z MINNEAPOLIS SOUNDING. UPPER JET IS SHIFTING NEWD INTO THE UPPER MS VALLEY. RAPID ACCAS DEVELOPMENT RECENTLY OBSERVED FROM NERN IA THROUGH SWRN WI IS LIKELY INDICATIVE OF NEWD EXPANDING ZONE OF AGEOSTROPHIC FORCING WITHIN THE UPPER JET EXIT REGION. THIS FORCING IN CONJUNCTION WITH FRONTAL CONVERGENCE WILL LIKELY MAINTAIN A DEEPER ZONE OF ASCENT THAT SHOULD EVENTUALLY ERODE THE CAP ENOUGH FOR STORMS TO DEVELOP ALONG THE COLD FRONT FROM ERN MN INTO NERN IA. STORMS WILL LIKELY MAINTAIN DISCRETE MODES FOR SEVERAL HOURS AND WILL BE EMBEDDED WITHIN STRONG DEEP LAYER WIND AND VERTICAL SHEAR SUPPORTIVE OF SUPERCELLS. LARGEST HODOGRAPHS ARE EXPECTED ACROSS CNTRL THROUGH NRN WI WHERE NEAR SURFACE WINDS SHOULD REMAIN BACKED TO SLY EAST OF THE SURFACE LOW WITH 0-1 KM STORM RELATIVE HELICITY EXCEEDING 250 M2/S2. STORMS DEVELOPING WITHIN THIS ENVIRONMENT WILL LIKELY BECOME CAPABLE OF PRODUCING STRONG TORNADOES...VERY LARGE HAIL AND DAMAGING WIND. Link to comment Share on other sites More sharing options...
TimChgo9 Posted April 10, 2011 Share Posted April 10, 2011 1 pm briefing from NWS LOT... They are looking at storms firing along the front, due to arrive later this evening. More organized south of I-80, and more scattered north of I-80. Low (not zero) chance of tornados. Link to comment Share on other sites More sharing options...
Powerball Posted April 10, 2011 Share Posted April 10, 2011 Link to comment Share on other sites More sharing options...
A-L-E-K Posted April 10, 2011 Share Posted April 10, 2011 northeast iowa looks close to going off Link to comment Share on other sites More sharing options...
janetjanet998 Posted April 10, 2011 Author Share Posted April 10, 2011 northeast iowa looks close to going off the CU still looks slightly elevated though(perhaps above the CAP and SPC did say they were ACCAS.. if they blow up into surface base they would be ahead of another line that should develop more west Link to comment Share on other sites More sharing options...
wisconsinwx Posted April 10, 2011 Share Posted April 10, 2011 Looks like just what I feared. Convection in NE Iowa and SW Wisconsin will move just north of here, and convection in Missouri and Illinois will move just south, meaning we're probably in between. Maybe we have a shot at the southern cells of the northern zone of storms. Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted April 10, 2011 Share Posted April 10, 2011 Looks like just what I feared. Convection in NE Iowa and SW Wisconsin will move just north of here, and convection in Missouri and Illinois will move just south, meaning we're probably in between. Maybe we have a shot at the southern cells of the northern zone of storms. Yep... We are riding the bust train. Link to comment Share on other sites More sharing options...
wisconsinwx Posted April 10, 2011 Share Posted April 10, 2011 Yep... We are riding the bust train. Another minor hope is maybe an isolated cell or two will develop in between. There is plenty of instability, although not tornadic instability. Link to comment Share on other sites More sharing options...
BadgerWXman Posted April 10, 2011 Share Posted April 10, 2011 Why god why can I not still be in Madison today... Link to comment Share on other sites More sharing options...
A-L-E-K Posted April 10, 2011 Share Posted April 10, 2011 Yep... We are riding the bust train. coverage in our area won't be great but there will be a couple nice cells in the region Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted April 10, 2011 Share Posted April 10, 2011 Another minor hope is maybe an isolated cell or two will develop in between. There is plenty of instability, although not tornadic instability. I would even take some nice hail. Or this is me just bargaining and trying to cope with my disappointment. Link to comment Share on other sites More sharing options...
wisconsinwx Posted April 10, 2011 Share Posted April 10, 2011 I still don't get how in the world Northern and Central Wisconsin can be more primed for severe weather than Southern. Not only did they get the complex of convection last night and are getting instability showers and storms currently, but the warm front is moving through as we speak. Meanwhile, we have had no rain move through in the Milwaukee area in the last two or three days, and got the sun to come out nice and early. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 10, 2011 Share Posted April 10, 2011 Some cumulus development along the dryline further west in Iowa now. Link to comment Share on other sites More sharing options...
Justin Posted April 10, 2011 Share Posted April 10, 2011 Looks like a little fine line of bumpy cumulus trying to develop now from Mason City to just NW of Des Moines too. Can start to see this zone developing in the last 30 min or so. That appears to be right on the frontal boundary, although the dew points dropping through Central Iowa is a bit of a concern as to whether that area of cumulus can go off. Northeast Iowa is very, very close to lighting up in the next hour or so I think. Link to comment Share on other sites More sharing options...
Kevin Askew Posted April 10, 2011 Share Posted April 10, 2011 Not implying this day to be a bust by a long shot, there will be plenty of severe weather, but in past, when we busted I like the term "We caught a bustnado" on our downing outing lol Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 10, 2011 Share Posted April 10, 2011 I would watch the little cu field along the IA/MN border. also FEP is sitting at 81/66 with south winds. Link to comment Share on other sites More sharing options...
Justin Posted April 10, 2011 Share Posted April 10, 2011 There is also a little grey line on the radar echoes showing up to the NW and W of Des Moines in conjunction with these cumulus clouds as well. I can see it on SPC's radar page for the MW sector. Have to wait and see if this starts bubbling up or not. Link to comment Share on other sites More sharing options...
A-L-E-K Posted April 10, 2011 Share Posted April 10, 2011 Looks like a little fine line of bumpy cumulus trying to develop now from Mason City to just NW of Des Moines too. Can start to see this zone developing in the last 30 min or so. That appears to be right on the frontal boundary, although the dew points dropping through Central Iowa is a bit of a concern as to whether that area of cumulus can go off. Northeast Iowa is very, very close to lighting up in the next hour or so I think. Link to comment Share on other sites More sharing options...
janetjanet998 Posted April 10, 2011 Author Share Posted April 10, 2011 still decent turning Link to comment Share on other sites More sharing options...
Jim Marusak Posted April 10, 2011 Share Posted April 10, 2011 currently outside here in st paul, cu7 winds estd 220 12g18 clouds moving sw to ne. and as a side note to the MCD, here's the link to the 18Z special sounding out at chanhassen. http://www.spc.noaa....18_OBS/last.gif with the current temp, i did a quick sounding analysis, and the cu field i am seeing will be tcu's soon as the cap's about to blow. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 10, 2011 Share Posted April 10, 2011 We decided to target the New Hampton Iowa area, and adjust from there. Not liking the surface winds being as veered as they are, but we'll see what happens I guess. That line of cumulus along the front/dryline should ignite here over the next hour or two. Link to comment Share on other sites More sharing options...
Indystorm Posted April 10, 2011 Share Posted April 10, 2011 From LaCrosse NWS office webcam Link to comment Share on other sites More sharing options...
Powerball Posted April 10, 2011 Share Posted April 10, 2011 The clouds in Iowa and Wisconsin look a little too flat and stratusy for my liking.. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 10, 2011 Share Posted April 10, 2011 The clouds in Iowa and Wisconsin look a little too flat and stratusy for my liking.. With the amount of forcing about to arrive that will be changing in a big way very soon. Link to comment Share on other sites More sharing options...
Jonbo Posted April 10, 2011 Share Posted April 10, 2011 Still a toasty 87/55 in DSM area. Haven't seen too much here visibly yet but definitely would love to see it develop out here more. Link to comment Share on other sites More sharing options...
janetjanet998 Posted April 10, 2011 Author Share Posted April 10, 2011 The clouds in Iowa and Wisconsin look a little too flat and stratusy for my liking.. yes they seem to be slighly elevated however I have seen the in the past where they can actually help the winds stay backed...when things clear out winds will often veer faster right now most of WI has backed SSE winds ..expect near the IL border the convection may form just behind those clouds..these would be "in front of the line" type storms..the line should form further west Link to comment Share on other sites More sharing options...
msp Posted April 10, 2011 Share Posted April 10, 2011 well, CF sure passed through here and with it the chances for svr wx. down to 59F now from 74F an hour or two ago. Link to comment Share on other sites More sharing options...
Reed Stough Posted April 10, 2011 Share Posted April 10, 2011 Things should get going soon. CIN seems to be lowering rapidly as the Height Falls move in. CAPE, M. Conv, LI, Shear appear pretty good. Only thing is Helicity is way to the north of where I would expect to see where the major Tornadoes might develop. Also, at least to the latest SPC meso charts the region I expect to see the severe weather is still in the Anti-Cyclonic region of the Jet, so we may have to wait a little longer. Link to comment Share on other sites More sharing options...
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