Thundersnow12 Posted August 2, 2011 Share Posted August 2, 2011 Btw, I'm seeing an OFB from near Portage westward to just north of Prairie du Chien. If so, we in SE Wisconsin might not have an OFB ruin our instability. I think the dewpoint in the 50s in Juneau is an indication of that OFB. how can you say that when that obs site is AHEAD of the outflow boundary? I find that dew point suspect when all surrounding areas are in the low-mid 70's Link to comment Share on other sites More sharing options...
wisconsinwx Posted August 2, 2011 Share Posted August 2, 2011 how can you say that when that obs site is AHEAD of the outflow boundary? I find that dew point suspect when all surrounding areas are in the low-mid 70's It seemed suspect to me as well, but it's quite possible the OFB extends farther east than evident on radar. It was just about even. It might be lower as well because of rain cooled air as it is approaching. Link to comment Share on other sites More sharing options...
wisconsinwx Posted August 2, 2011 Share Posted August 2, 2011 Even though convection is a short distance off to the northwest, we are experiencing some sun right now. I'm surprised but we may narrowly keep ourselves in the better areas of instability. That convection better weaken, burn off, or stay to the north, though. Link to comment Share on other sites More sharing options...
TimChgo9 Posted August 2, 2011 Share Posted August 2, 2011 Looking at the potential, and heading out for more flashlights, and other supplies to ride out another power outage. The power has been failing in different parts of the north end of my town, and next door in LaGrange ever since the storms on July 11th. Between tje June 21st, and July 11th storms, ComEd has been replacing poles and wire, the electrical system in LaGrange, Western Springs, and LaGrange Park took a beating from the last two storms to come through, as well as all of the storms we had last week, and the week before. Parts of the neighborhood around me have been without power at various times throughout the last two and half weeks, with all the hot weather. Transformers have been popping, and lines have been going down all over this area since the hot weather set in. Hopefully we can get through the storms today without any serious problems.... Link to comment Share on other sites More sharing options...
wisconsinwx Posted August 2, 2011 Share Posted August 2, 2011 The latest RUC backup has a spread the wealth squall line sweeping through pretty much all of S Wisconsin and N Illinois, with a few discrete storms forming ahead of it. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted August 2, 2011 Share Posted August 2, 2011 not good...storms would move into an impressive environment.. Link to comment Share on other sites More sharing options...
Chicago Storm Posted August 2, 2011 Share Posted August 2, 2011 Link to comment Share on other sites More sharing options...
wisconsinwx Posted August 2, 2011 Share Posted August 2, 2011 not good...storms would move into an impressive environment.. Could a Moderate Risk be forthcoming? Link to comment Share on other sites More sharing options...
Thundersnow12 Posted August 2, 2011 Share Posted August 2, 2011 a tad better lol Link to comment Share on other sites More sharing options...
L.B. LaForce Posted August 2, 2011 Share Posted August 2, 2011 An interesting vis sat loop over today's threat area. http://climate.cod.edu/flanis/2km.php?loop=1&type=vis®ion=MI&numimages=24 Link to comment Share on other sites More sharing options...
Thundersnow12 Posted August 2, 2011 Share Posted August 2, 2011 12z 4km wrf.. Link to comment Share on other sites More sharing options...
A-L-E-K Posted August 2, 2011 Share Posted August 2, 2011 12z 4km wrf.. Almost looks like two areas of convection merge right over the northside of the city and then rides an intense updraft right through downtown. Link to comment Share on other sites More sharing options...
Chicago Storm Posted August 2, 2011 Share Posted August 2, 2011 12z 4km wrf.. Poor initialization... Link to comment Share on other sites More sharing options...
tornadotony Posted August 2, 2011 Share Posted August 2, 2011 RUC keeps the sfc winds way backed...I didn't think the NAM could be that off on 0-1km SRH this late in the summer (like it often actually is during the fall-spring) so we'll see if that verifies. Verbatim, with extreme instability, high helicity, and shear vectors perpendicular to the initiating boundary, the RUC would be a horrible day for WI and IL, maybe into IN. Link to comment Share on other sites More sharing options...
RobertSul Posted August 2, 2011 Share Posted August 2, 2011 I'm seeing all this talk of IN, WI, and IL. Is MI out of the woods? Link to comment Share on other sites More sharing options...
tornadotony Posted August 2, 2011 Share Posted August 2, 2011 I'm seeing all this talk of IN, WI, and IL. Is MI out of the woods? MI is a tough call because of ongoing convection. Given that afternoon initiation should be E IA/SW WI/NW IL, I would think MI escapes the worst. Link to comment Share on other sites More sharing options...
sc2man13 Posted August 2, 2011 Share Posted August 2, 2011 What time are these storms progged to initialize over the Chicagoland area exactly? Link to comment Share on other sites More sharing options...
A-L-E-K Posted August 2, 2011 Share Posted August 2, 2011 What time are these storms progged to initialize over the Chicagoland area exactly? give or take 4-8 pm from northwest to southeast. Link to comment Share on other sites More sharing options...
wisconsinwx Posted August 2, 2011 Share Posted August 2, 2011 What time are these storms progged to initialize over the Chicagoland area exactly? Based on the models, they initialize further north and west late afternoon, probably around 3 or 4, then move SE, approaching the Chicago area around 8 or 9. That said, supercells might initiate ahead of the potential squall line. Link to comment Share on other sites More sharing options...
A-L-E-K Posted August 2, 2011 Share Posted August 2, 2011 Gilbert All data suggests that a squall line will develop across southern Wisconsin through eastern Iowa late this afternoon and then head southeast across northeastern and north-central Illinois between PM and midnight...with the latest timing either side of 7 PM in DeKalb...and backed up by short-range model guidance. All indications are that the worst of it may stay just northeast of DeKalb...and in fact, i almost went with a high risk for Hoffman Estates and Naperville, but confidence is not all that high. The model forecast winds are higher than actually seen with data, leading to a somewhat lower confidence that he models will be right. Nevertheless, even with a bit weak mid-level winds, the scenario is still ripe for a band of strong to severe thunderstorms to develop north and northwest of the area this afternoon and move into our region at and after dinnertime. Given the magnitude of the instability and atmospheric wind profiles, winds of 60-75 MPH are possible with any severe thunderstorm. Much lower but still significant chances of hail are possible, along with an isolated tornado...with winds above the surface veering with height some. Link to comment Share on other sites More sharing options...
tornadotony Posted August 2, 2011 Share Posted August 2, 2011 Based on the models, they initialize further north and west late afternoon, probably around 3 or 4, then move SE, approaching the Chicago area around 8 or 9. That said, supercells might initiate ahead of the potential squall line. I don't think that's what's going to happen. There's going to be a cap once you get a distance S of the front. My thinking is you get supercells off the front and they evolve into the squall line eventually. Link to comment Share on other sites More sharing options...
wisconsinwx Posted August 2, 2011 Share Posted August 2, 2011 I don't think that's what's going to happen. There's going to be a cap once you get a distance S of the front. My thinking is you get supercells off the front and they evolve into the squall line eventually. May well be. Where do you think supercell development is most likely? SC Wisconsin? That is probably a likely place given one mini cell has already developed near Madison. Link to comment Share on other sites More sharing options...
A-L-E-K Posted August 2, 2011 Share Posted August 2, 2011 May well be. Where do you think supercell development is most likely? SC Wisconsin? That is probably a likely place given one mini cell has already developed near Madison. That little cell is not associated with the cold front which will set off the storms this evening, it's probably just flaring up on the edge of the old nocturnal MCS and the llj. Link to comment Share on other sites More sharing options...
L.B. LaForce Posted August 2, 2011 Share Posted August 2, 2011 12z Parallel NAM fwiw: Link to comment Share on other sites More sharing options...
wisconsinwx Posted August 2, 2011 Share Posted August 2, 2011 The convection's winding down and moving away in WI, so after about 1 or 2, destabilization will probably be rampant throughout the southern part of the state. Link to comment Share on other sites More sharing options...
andyhb Posted August 2, 2011 Share Posted August 2, 2011 MESOSCALE DISCUSSION 1833 NWS STORM PREDICTION CENTER NORMAN OK 1257 PM CDT TUE AUG 02 2011 AREAS AFFECTED...CNTRL/ERN IA...FAR SERN MN...SRN/CNTRL WI...CNTRL/NRN IL CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 021757Z - 021930Z PORTIONS OF CNTRL/ERN IA...FAR SERN MN...SRN/CNTRL WI AND CNTRL/NRN IL ARE BEING MONITORED FOR SURFACE BASED THUNDERSTORM INITIATION. THIS WILL LIKELY TAKE PLACE BY MID AFTERNOON. ONE OR MORE WW/S WILL THEN BE NEEDED ACROSS THE AREA. AT 17Z...SURFACE ANALYSIS INDICATED A MOBILE AREA OF LOW PRESSURE WAS CENTERED 30 WNW OF LSE IN FAR SERN MN. A WARM FRONT EXTENDED EWD FROM THE LOW ACROSS SRN WI...WHILE A COLD FRONT TRAILED SWWD INTO CNTRL IA. STRONG HEATING IS OCCURRING ALONG AND S OF THE WARM FRONT...WITH TEMPERATURES RISING INTO THE UPR 80S TO LOW 90S. HOWEVER...VISIBLE SATELLITE PRESENTATION OF TOWERING CUMULUS FORMING ALONG THE COLD FRONT IN NERN IA SUGGESTS THE ATMOSPHERE REMAINS CAPPED THUS FAR. LATEST SHORT TERM MODEL GUIDANCE INDICATES THIS WILL CHANGE BY MID AFTERNOON...AS CONTINUED SURFACE HEATING AND FRONTAL CONVERGENCE/ASCENT AIDS IN THUNDERSTORM INITIATION INVOF THE WARM AND COLD FRONTAL BOUNDARIES. LINE SEGMENTS AND STORM CLUSTERS WILL BE POSSIBLE ALONG THE COLD FRONT...AND WILL HAVE THE POTENTIAL TO PRODUCE LARGE HAIL/DAMAGING WINDS GIVEN MLCAPE VALUES AOA 3000 J/KG...30+ KT MIDLEVEL WLYS OVERSPREADING THE FRONT...AND A HOT BOUNDARY LAYER/STEEP LOW-LEVEL LAPSE RATE ENVIRONMENT. THIS ACTIVITY WILL THEN MOVE EWD INTO PORTIONS OF CNTRL/NRN IL...WHERE IT MAY GROW UPSCALE INTO A QLCS. FARTHER N OVER PORTIONS OF SRN/CNTRL WI...AREA VWP/S AND RUC FORECAST SOUNDINGS INDICATE THE POTENTIAL FOR LOWER CLOUD BASES AND STRONGER LOW AND DEEP LAYER VERTICAL WIND SHEAR...FAVORABLE FOR ROTATING UPDRAFTS. THOUGH DAMAGING WINDS/LARGE HAIL WILL BE THE PRIMARY SVR WEATHER THREATS...TORNADOES WILL ALSO BE POSSIBLE WITH ANY STORMS THAT INTERACT WITH THE SURFACE WARM FRONT. ..GARNER.. 08/02/2011 Link to comment Share on other sites More sharing options...
wisconsinwx Posted August 2, 2011 Share Posted August 2, 2011 The tail end of the MCS is giving us a brief thunderstorm...key word brief. That MCD has obviously caught my eye. Link to comment Share on other sites More sharing options...
andyhb Posted August 2, 2011 Share Posted August 2, 2011 MESOSCALE DISCUSSION 1834 NWS STORM PREDICTION CENTER NORMAN OK 0125 PM CDT TUE AUG 02 2011 AREAS AFFECTED...MUCH OF LWR MI CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 021825Z - 022000Z UPSTREAM CONVECTION MOVING ACROSS LK MI IS BEING MONITORED FOR INTENSIFICATION AS IT ENTERS LWR MI. WW MAY BE NEEDED THIS AFTERNOON. SURFACE ANALYSIS AT 18Z SHOWS A WARM FRONT RETREATING NWD INTO CNTRL LWR MI...WITH TEMPERATURES S OF THE BOUNDARY QUICKLY RISING THROUGH THE 80S. WHEN COUPLED WITH LOW 70S DEWPOINTS...ATMOSPHERE IS EXPECTED TO BECOME MODERATELY UNSTABLE BY MID-AFTERNOON /I.E. MLCAPE VALUES APPROACHING 2000 J PER KG/. MEANWHILE...REMNANTS OF EARLIER MCS OVER THE UPR MS VALLEY REGION IS MOVING ACROSS LK MI. AS IT ENCOUNTERS THE DESTABILIZING AIRMASS OVER LWR MI...REINTENSIFICATION MAY TAKE PLACE. GIVEN THE PRESENCE OF FAIRLY STRONG MIDLEVEL FLOW /NEAR 40 KT AT 6 KM AGL PER GRR VWP/ AND EFFECTIVE BULK SHEAR VALUES AROUND 40 KT...ORGANIZED SVR STORM DEVELOPMENT WILL BE POSSIBLE...POSING MAINLY A DAMAGING WIND AND LARGE HAIL THREAT. HOWEVER...ENLARGED LOW-LEVEL HODOGRAPH STRUCTURE IS FORECAST ALONG THE WARM FRONT LATER THIS AFTERNOON...WHICH COULD AID IN A LOCALIZED TORNADO THREAT AS WELL. CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED FOR A POSSIBLE WW. ..GARNER.. 08/02/2011 Link to comment Share on other sites More sharing options...
tornadotony Posted August 2, 2011 Share Posted August 2, 2011 Nice TCU in IA...this thing may be ready to blow. Link to comment Share on other sites More sharing options...
A-L-E-K Posted August 2, 2011 Share Posted August 2, 2011 brief update from LOT, not terribly impressed. NOW TO FOCUS MORE ON TSRA AND TIMING. THE ENVIRONMENT SHOULDREMAIN STABLE UNTIL CLOSER TO 00Z ACROSS NORTHERN IL/NORTHWEST IN...HOWEVER A CLOSE MONITOR ON BUILDING CUMULUS FIELD ACROSS NORTH CENTRAL IOWA AND SOUTHEAST MINNESOTA IS NEEDED. THIS AREA OF CLOUD COVER WILL CONTINUE TO SLIDE EAST. GUIDANCE HAS INDICATED THAT THE BEST TIMING FOR CONVECTION WILL OCCUR ARND 01Z THEN COVERAGE WILL EXPAND THROUGH 07Z WHEN FROPA. WINDS WILL CONTINUE TO BE GUSTY FROM THE SOUTHWEST PRIOR TO CONVECTION DEVELOPMENT. STRONG WINDS WILL BE THE MAIN THREAT WITH ANY STRONG THUNDERSTORMS...AND A SLIGHT CHANCE THAT SOME TSRA COULD REACH SEVERE LIMITS. THE MAIN HAZARD WOULD BE DAMAGING WINDS WITH THE TIMING BETWEEN 03-07Z. THIS TIME MAY NEED Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.