OceanStWx Posted March 20, 2011 Share Posted March 20, 2011 Just ran through some quick calculations based on afternoon forecast parameters. I went with Iowa City for the point location, with temp/dewpoint of 68/55, putting CAPEs around 1000 j/kg. This yields essentially marginal severe wind gusts and EF0 potential. So it really appears like mid 50s dews are the key. If we can increase things beyond that the potential should really start to go up. The key is increasing those low level theta e lapse rates. Link to comment Share on other sites More sharing options...
OceanStWx Posted March 20, 2011 Share Posted March 20, 2011 You can see here that we have theta e advection taking places along the warm front, but watch and see if we get close to the contours especially. Getting theta e to 330 K would go a long way. Link to comment Share on other sites More sharing options...
OceanStWx Posted March 20, 2011 Share Posted March 20, 2011 And the first warning of the day... 206 PM CDT SUN MAR 20 2011 THE NATIONAL WEATHER SERVICE IN THE QUAD CITIES HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... SOUTHEASTERN STEPHENSON COUNTY IN NORTHWEST ILLINOIS... * UNTIL 245 PM CDT. * AT 204 PM CDT...TRAINED SPOTTERS REPORTED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL. THIS STORM WAS LOCATED APPROXIMATELY NEAR FREEPORT...AND MOVING NORTHEAST AT 40 MPH. North of the warm front, so a hailer with sub severe wind gusts possible. The KDMX 88D is picking up echos at over 50kft on that cell. Link to comment Share on other sites More sharing options...
cyclone77 Posted March 20, 2011 Share Posted March 20, 2011 Dewpoints continue to increase over southern Iowa. Many locations between 56-58 now. Even a few 60 degree readings, but those aren't ASOS. If we can get them a bit higher up towards 60 like what the RUC has been showing, then we'll be in pretty good shape. Several locations over the 70 degree mark BTW. Link to comment Share on other sites More sharing options...
OceanStWx Posted March 20, 2011 Share Posted March 20, 2011 Dewpoints continue to increase over southern Iowa. Many locations between 56-58 now. Even a few 60 degree readings, but those aren't ASOS. If we can get them a bit higher up towards 60 like what the RUC has been showing, then we'll be in pretty good shape. Several locations over the 70 degree mark BTW. I like that we are heating both sides of the boundary now along Highway 30 in eastern Iowa. Cedar Rapids still very much on the "cool side" of the boundary with backing winds but temperature and dewpoint both increasing rapidly, while Iowa City's wind has remained steady and temps have shot into the 60s over mid 50s. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 20, 2011 Share Posted March 20, 2011 nice top on the storm south of the IL/WI border Link to comment Share on other sites More sharing options...
cyclone77 Posted March 20, 2011 Share Posted March 20, 2011 I like that we are heating both sides of the boundary now along Highway 30 in eastern Iowa. Cedar Rapids still very much on the "cool side" of the boundary with backing winds but temperature and dewpoint both increasing rapidly, while Iowa City's wind has remained steady and temps have shot into the 60s over mid 50s. I think we're in the full warm sector here now. We're up to 61 with a southerly wind. We had stalled at about 56 for awhile, but it quickly jumped up over the last 15-20 minutes. It's almost like there's two warm fronts. Link to comment Share on other sites More sharing options...
OceanStWx Posted March 20, 2011 Share Posted March 20, 2011 I think we're in the full warm sector here now. We're up to 61 with a southerly wind. We had stalled at about 56 for awhile, but it quickly jumped up over the last 15-20 minutes. It's almost like there's two warm fronts. Basically the warm front and the remnant outflow boundary. The atmosphere has a memory, and while the warm front may get north of there, traces of the OFB will remain. Link to comment Share on other sites More sharing options...
OceanStWx Posted March 20, 2011 Share Posted March 20, 2011 As a complete aside, Portland set a record with 68 degrees on Friday. The next morning we picked up a quick 2 inches of snow, and just now we issued a winter storm warning for tomorrow. Glad I have this convection to distract me. Link to comment Share on other sites More sharing options...
cyclone77 Posted March 20, 2011 Share Posted March 20, 2011 SREF increased probabilities again. Link to comment Share on other sites More sharing options...
OceanStWx Posted March 20, 2011 Share Posted March 20, 2011 SREF increased probabilities again. My favorite "first guess" map. Link to comment Share on other sites More sharing options...
hawkeye_wx Posted March 20, 2011 Share Posted March 20, 2011 Link to comment Share on other sites More sharing options...
cyclone77 Posted March 20, 2011 Share Posted March 20, 2011 Temps have reached 70 as far north as Moline now. Dews in the warm sector didn't change much over the past hour. Still 55-60. Pretty impressive thermal ridge out ahead of the triple point. Link to comment Share on other sites More sharing options...
msp Posted March 20, 2011 Share Posted March 20, 2011 sitting in a lounge at ORD now that my flight from amsterdam has landed. got a delay at the gate over lightning. heckuva shelf cloud out the window; pity the glare ruins the camera shot. flights getting delayed here left and right. Link to comment Share on other sites More sharing options...
A-L-E-K Posted March 20, 2011 Share Posted March 20, 2011 sitting in a lounge at ORD now that my flight from amsterdam has landed. got a delay at the gate over lightning. heckuva shelf cloud out the window; pity the glare ruins the camera shot. flights getting delayed here left and right. from my place Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 20, 2011 Share Posted March 20, 2011 from my place nice looking laminar striations in the second pic. Link to comment Share on other sites More sharing options...
A-L-E-K Posted March 20, 2011 Share Posted March 20, 2011 nice looking laminar striations in the second pic. i was out walking the dog and noticed them without camera, by the time i got back and grabbed the camera, they weren't as impressive. Either way, a nice teaser of more spring like weather. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 20, 2011 Share Posted March 20, 2011 some nice looking HCR's on vis sat in northern MO/southern IA. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 20, 2011 Share Posted March 20, 2011 upper level trof/jet max nosing into central IA Link to comment Share on other sites More sharing options...
cyclone77 Posted March 20, 2011 Share Posted March 20, 2011 It's a bit hard to tell, but it looks like there's a band of clouds east of Des Moines with some decent vertical development. Link to comment Share on other sites More sharing options...
OceanStWx Posted March 20, 2011 Share Posted March 20, 2011 It's a bit hard to tell, but it looks like there's a band of clouds east of Des Moines with some decent vertical development. The front is through Des Moines now, so it should start impacting the theta e ridge soon. Not overly impressed with the moisture return into southeast Iowa, but does look like Iowa City hit my mark of 55 for a dewpoint. So still the potential for severe gusts there. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 20, 2011 Share Posted March 20, 2011 really cool seeing the HCR's align with the sfc flow, also MUCAPE values are >1000 j/kg now over most of northern IL Link to comment Share on other sites More sharing options...
cyclone77 Posted March 20, 2011 Share Posted March 20, 2011 Crickets. Link to comment Share on other sites More sharing options...
southmountainwx Posted March 20, 2011 Share Posted March 20, 2011 70F and 58DP at KOTM nothing popping anywhere yet. Link to comment Share on other sites More sharing options...
OceanStWx Posted March 20, 2011 Share Posted March 20, 2011 70F and 58DP at KOTM nothing popping anywhere yet. 40dBZ pixel just west of Cedar Rapids! Link to comment Share on other sites More sharing options...
cyclone77 Posted March 21, 2011 Share Posted March 21, 2011 The warm front's collapsing. We've dropped from 71 back to 58 over the past hour. Link to comment Share on other sites More sharing options...
Chicago Storm Posted March 21, 2011 Share Posted March 21, 2011 A look at the elevated storms as the sun sets... Link to comment Share on other sites More sharing options...
OceanStWx Posted March 21, 2011 Share Posted March 21, 2011 00z DVN sounding shows the cap well, a little more moisture would've gone a long way. Seems like 60+ dews would've done it. Link to comment Share on other sites More sharing options...
Indystorm Posted March 21, 2011 Share Posted March 21, 2011 Well at least I might get some elevated storms over my way tonight. Looks like they are firing now in north central/ne IL and certainly across Lake Michigan into Michigan to my north. Nothing like some rumbles of thunder to cheer Notre Dame on over Florida State later this evening. Link to comment Share on other sites More sharing options...
ksstormhunter Posted March 21, 2011 Share Posted March 21, 2011 Not much happening across the IA regions. Looking at moisture tongue into the SE part of IA. Have good instability values across the areas, just need more moisture to work with. SmartModel still targeting the zone with the highest instabilty across the Central to Southern Part of IA. Also of note, a further bit eastward along the plume of CAPE values across the Illinois area, convections seems to be forming there. There is a nice tongue of CAPE's pushing through North Central IL. The storms in S. WI should enhance a bit, moving into that area. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.