Thundersnow12 Posted May 7, 2011 Share Posted May 7, 2011 00z NAM still looks interesting in IL on Monday. Parameters aren't extreme by any stretch but there is a pocket of stronger flow and the directional shear is hard to ignore. Unclear if there will be a well organized MCS or more scattered activity but anything that can root at the surface would be something to watch. cap looks weakest in southern IL and I'd imagine it would be had to get anything going with the EML only getting worse throughout the day. quite the southerly LLJ to even slightly backed the further north you go as well which lends to some very impressive 0-3km SRH values over the entire state. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted May 7, 2011 Share Posted May 7, 2011 Im sure this has happened before but it caught my eye quickly, cool to see the moisture get pulled all the way around and back south of the sfc low Link to comment Share on other sites More sharing options...
Hoosier Posted May 7, 2011 Share Posted May 7, 2011 cap looks weakest in southern IL and I'd imagine it would be had to get anything going with the EML only getting worse throughout the day. quite the southerly LLJ to even slightly backed the further north you go as well which lends to some very impressive 0-3km SRH values over the entire state. GFS really builds the instability on Monday but it has basically no precip in the southern 1/2 of IL. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted May 7, 2011 Share Posted May 7, 2011 GFS really builds the instability on Monday but it has basically no precip in the southern 1/2 of IL. Ya with crazy numbers on tuesday around here...dew points in the low 70's with CAPE values pushing 4500 j/kg or more. Link to comment Share on other sites More sharing options...
cmichweather Posted May 7, 2011 Share Posted May 7, 2011 I'm still trying to decide if i'll be able to chase monday-tuesday, I'm thinking based on distance I might see if i can get some other grad students to come on down to southern SD on monday and play the warm front, should have some storms not 2 worried about the cap and cape and srh are there but we'll see. Usually the nam will struggle with underplaying the daytime heating and instability will be a bit 2 low, I like the warm front as of right now but as we all know convective debris and placement of the all the features is the deciding factor. Tuesday is probably a bit 2 far away but might be a decent event for the majority of our midwest posters. Link to comment Share on other sites More sharing options...
thewxmann Posted May 7, 2011 Share Posted May 7, 2011 Based on my experience watching severe weather out here for the past 5-6 years, I think it is indeed. And that's what makes this year so frustrating. Any other year, the H5 map progged for Monday would have me salivating. It doesn't look all that dissimilar to the Greensburg case, synoptically. But the hellacious cap will almost certainly rip the setup from our under feet, except possibly along the warm front in NE/IA. I still think that the best bet for significant Plains activity will be from I-70 northward this year, as snowpack in the central and northern Rockies is much better, along with less severe drought in the adjacent central and northern High Plains. Tuesday and Wednesday still look fairly interesting, yet imperfect due to the trough beginning to roll over and shear out. Nah... for Greensburg we had a strong upper jet punching into the warm sector... the increase in upper air forcing near dusk in conjunction with a subtle DL bulge was enough to initiate the Greensburg supercell despite the strong cap. The dynamics are much much weaker with this upcoming system. And instead of a jet punching into the warm sector, we'll have to hope for some s/w's embedded in the SW flow. Link to comment Share on other sites More sharing options...
brettjrob Posted May 7, 2011 Share Posted May 7, 2011 Nah... for Greensburg we had a strong upper jet punching into the warm sector... the increase in upper air forcing near dusk in conjunction with a subtle DL bulge was enough to initiate the Greensburg supercell despite the strong cap. The dynamics are much much weaker with this upcoming system. And instead of a jet punching into the warm sector, we'll have to hope for some s/w's embedded in the SW flow. There are notable differences, to be sure, but I disagree that the look of the upper-level jet is completely incomparable: http://www.spc.noaa.gov/exper/ma_archive/images_s4/20070505/00_300mb.gif vs. http://www.twisterdata.com/data/models/nam/221/maps/2011/05/07/00/NAM_221_2011050700_F72_WSPD_300_MB.png I will concede the jet streak is a hair faster and poised to intersect the dryline a bit further S in the Greensburg case. Aside from that, I'd say the position of the trough axis and the vertical wind profile ahead of the dryline looks fairly similar. I certainly don't expect a similar outcome, though. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 7, 2011 Share Posted May 7, 2011 Im sure this has happened before but it caught my eye quickly, cool to see the moisture get pulled all the way around and back south of the sfc low Yes agreed. Sounds silly--but I am excited to experience an actual true plains dryline. Link to comment Share on other sites More sharing options...
csnavywx Posted May 7, 2011 Share Posted May 7, 2011 Danville Illinois hodo is pretty impressive. I'm not sure how the backing upper levels could affect things. UL backing is actually desirable, in my opinion. It's only the lowest 2-3km that truly matters with respect to turning/veering. Link to comment Share on other sites More sharing options...
Ed Lizard Posted May 7, 2011 Share Posted May 7, 2011 I continue to be amazed at some of these set-ups over the last 45 days with strong early season capping - I noted in one or two AFD's today that the subject was once again brought up. I wonder if the strong capping is related to the dry conditions over the Oklahoma and Texas region. It is unusual and has been unusual for awhile now to see some of these capping numbers. On another note - nice dry line next week I'd think that might have a slight effect on low level moisture, but I think the real culprit is the drought in the Mexican states bordering Texas. Jorge has been posting some fire/drought stuff from Nuevo Leon. BTW, discussed a bit on the Chasecation thread, little concerned PWs are actually too high in Oklahoma (at least for phtogenic storms), GFS and Euro have a touch of difference, but both seem to support a big ticket event around I-35 in Oklahoma Wednesday. Link to comment Share on other sites More sharing options...
k*** Posted May 7, 2011 Share Posted May 7, 2011 Yes agreed. Sounds silly--but I am excited to experience an actual true plains dryline. drylines are boring most of the time Link to comment Share on other sites More sharing options...
cmichweather Posted May 7, 2011 Share Posted May 7, 2011 UL backing is actually desirable, in my opinion. It's only the lowest 2-3km that truly matters with respect to turning/veering. I've always felt that way as well. Link to comment Share on other sites More sharing options...
AtticaFanatica Posted May 7, 2011 Share Posted May 7, 2011 drylines are boring most of the time blasphemy Link to comment Share on other sites More sharing options...
Hoosier Posted May 7, 2011 Share Posted May 7, 2011 UL backing is actually desirable, in my opinion. It's only the lowest 2-3km that truly matters with respect to turning/veering. Hope this isn't a painfully obvious answer but could you explain why? Link to comment Share on other sites More sharing options...
cyclone77 Posted May 7, 2011 Share Posted May 7, 2011 SPC upgraded tornado probabilities to 5% over eastern Illinois and western Indiana for later today. The setup I was mentioning a few nights ago still looks pretty decent, just further east/southeast. Gotta give credit to the GFS and RGEM for being correct on the timing and location. The NAM was holding things further west. Link to comment Share on other sites More sharing options...
JoMo Posted May 7, 2011 Share Posted May 7, 2011 Wed looks like the best chance for severe around here back into KS and OK. The 12z GFS is stronger with the winds at 500 MB and below than both the 06 and 00z runs. Link to comment Share on other sites More sharing options...
Hoosier Posted May 7, 2011 Share Posted May 7, 2011 SPC upgraded tornado probabilities to 5% over eastern Illinois and western Indiana for later today. The setup I was mentioning a few nights ago still looks pretty decent, just further east/southeast. Gotta give credit to the GFS and RGEM for being correct on the timing and location. The NAM was holding things further west. Hmm, I gotta start paying attention to today. Link to comment Share on other sites More sharing options...
Hoosier Posted May 7, 2011 Share Posted May 7, 2011 Marginal instability and low level flow is on the weak side but nice turning and increasing flow in the mid/upper levels. Low freezing levels should help with a hail threat. Link to comment Share on other sites More sharing options...
AtticaFanatica Posted May 7, 2011 Share Posted May 7, 2011 Hope this isn't a painfully obvious answer but could you explain why? colder air aloft maybe...I haven't paid attention too much to that in particular but I don't think I've had too much luck with sinusoidal hodographs, VPGFs get all funky unless the backing is subtle Link to comment Share on other sites More sharing options...
Hoosier Posted May 7, 2011 Share Posted May 7, 2011 Link to comment Share on other sites More sharing options...
cmichweather Posted May 7, 2011 Share Posted May 7, 2011 storms are starting to fire up in central IL. Link to comment Share on other sites More sharing options...
cyclone77 Posted May 7, 2011 Share Posted May 7, 2011 storms are starting to fire up in central IL. Yeah that cell southeast of Pontiac already has a near 1" hail marker on it in just a few scans. Looks like SPC went with just a severe thunderstorm watch. Link to comment Share on other sites More sharing options...
mnchaser Posted May 7, 2011 Share Posted May 7, 2011 Southern MN possibly looks pretty decent for Tuesday by looking at the 12z NAM with better shear compared to areas further south and sfc based capes upwards of 6000 and LI's as low as -10!:arrowhead:The surge of moisture with this run is insane. Things could/will change but near the triple point looks like best the place to be for storms to break through the cap. Link to comment Share on other sites More sharing options...
oldlogin Posted May 7, 2011 Share Posted May 7, 2011 Yeah that cell southeast of Pontiac already has a near 1" hail marker on it in just a few scans. Looks like SPC went with just a severe thunderstorm watch. Ford County storm now warned and moving East Link to comment Share on other sites More sharing options...
cyclone77 Posted May 7, 2011 Share Posted May 7, 2011 Nice cell split a little while ago on the severe warned storm in eastern Illinois. Some other cells are firing to the southwest of the dominant right split and are feeding into it. Per SPC there's 1500j/kg surface cape nosing into this area. Link to comment Share on other sites More sharing options...
oldlogin Posted May 7, 2011 Share Posted May 7, 2011 BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 406 PM CDT SAT MAY 7 2011 THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A * TORNADO WARNING FOR... SOUTHEASTERN FORD COUNTY... SOUTHWESTERN IROQUOIS COUNTY... * UNTIL 445 PM CDT * AT 404 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED NEAR PAXTON...AND MOVING SOUTHEAST AT 40 MPH. * LOCATIONS IMPACTED INCLUDE... MAINLY RURAL AREAS OF SOUTHEASTERN FORD COUNTY Link to comment Share on other sites More sharing options...
oldlogin Posted May 7, 2011 Share Posted May 7, 2011 And this BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE LINCOLN IL 406 PM CDT SAT MAY 7 2011 THE NATIONAL WEATHER SERVICE IN LINCOLN HAS ISSUED A * TORNADO WARNING FOR... NORTHEASTERN CHAMPAIGN COUNTY IN EAST CENTRAL ILLINOIS... NORTHERN VERMILION COUNTY IN EAST CENTRAL ILLINOIS... * UNTIL 445 PM CDT. * AT 403 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED NEAR PAXTON...AND MOVING SOUTHEAST AT 35 MPH. * LOCATIONS IMPACTED INCLUDE... DANVILLE...RANKIN...POTOMAC...HOOPESTON...ROSSVILLE...LUDLOW... ARMSTRONG...MIDDLE FORK WILDLIFE AREA...COLLISON...HENNING... ALVIN...BISMARCK AND VERMILION COUNTY AIRPORT. THIS INCLUDES INTERSTATE 57 BETWEEN MILE MARKERS 255 AND 257. THIS INCLUDES INTERSTATE 74 BETWEEN MILE MARKERS 216 AND 219. Link to comment Share on other sites More sharing options...
SEMIweather Posted May 7, 2011 Share Posted May 7, 2011 Link to comment Share on other sites More sharing options...
mnchaser Posted May 7, 2011 Share Posted May 7, 2011 Ummm It is May 7th, The title of the thread clearly says 8th-11th..Make a different topic if you want to post about today's severe weather. Link to comment Share on other sites More sharing options...
Chicago Storm Posted May 7, 2011 Share Posted May 7, 2011 Ummm It is May 7th, The title of the thread clearly says 8th-11th..Make a different topic if you want to post about today's severe weather. Hush. Link to comment Share on other sites More sharing options...
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