Hoosier Posted November 11, 2015 Share Posted November 11, 2015 HRRR has some redevelopment taking place near Chicago/over Lake Michigan around 2 AM. 18z 4 km NAM was sorta hinting at the same thing. There's some sfc based instability at that time so we'll see what comes of it. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted November 12, 2015 Share Posted November 12, 2015 SEVERE THUNDERSTORM WATCH INBOUND .MESOSCALE DISCUSSION...600 PM CSTCONTINUE TO ANALYZE THREAT FOR A PERIOD OF GUSTY SHOWERS ANDSTORMS THIS EVE...SOME OF WHICH MAY PRODUCE SEVERE GUSTS. ASEVERE THUNDERSTORM WATCH HAS BEEN COLLABORATED AND WILL BE ISSUEDSHORTLY FOR THE ILLINOIS CWA. ALSO ARE MONITORING FOR A PERIOD OFHIGHER END NON-THUNDERSTORM GUSTS TO POSSIBLY NEAR 60 MPHOVERNIGHT...WHICH HAS RESULTED IN AN INCREASE IN FORECAST WINDSPEEDS.LATEST HAND ANALYSIS INDICATES THE SURFACE LOW IS DOWN TO 988 MBAND CONTINUING TO DEEPEN IN CENTRAL IOWA WITH A WARM FRONTCURLING EAST AND THEN SOUTHWARD NEAR THE MISSISSIPPI RIVER. JUSTNORTH/NORTHEAST OF THIS FRONT...STRENGTHENING MOIST AND WARMADVECTION IS STARTING TO RESULT IN SCATTERED SHOWERS ACROSSNORTHWEST IL. THESE ARE LIKELY TO INCREASE IN COVERAGE INTO NORTHCENTRAL AND POSSIBLY NORTHEAST ILLINOIS EARLY THIS EVENING AHEADOF THE MAIN AXIS...AND ELEVATED INSTABILITY PER THE 21Z DVNSOUNDING AND LATEST ANALYSIS COULD SUPPORT THUNDER WITH ANY OFTHIS ACTIVITY. IT IS NOT LIKELY THAT THESE WOULD BE SEVERE BUT THEENVIRONMENTAL WIND FIELD IS SO STRONG THAT WILL NEED TO KEEP ANEYE ON SOME OF THIS ACTIVITY.THE WARM FRONT IS ADVANCING IN THE NARROW PLUME OF SURFACE BASEDINSTABILITY ON THE ORDER OF 100-200 J/KG AND HELPING TO SUPPORT AFOCUSED LINE OF CONVECTION WITH EMBEDDED NEAR TO SEVERE GUSTS ASWELL AS TRANSIENT AREAS OF ROTATION. DYNAMICS AND UPPER SUPPORTFOR LIFT ARE VERY IMPRESSIVE FOR THE ONGOING STORMS...WITHSTRENGTHENING 850MB WINDS OF 55-65 KT ON REGIONAL VAD PROFILERS.THESE WINDS WILL BE THE CONCERN WITH DOWNDRAFTS IN ANY ORGANIZEDSTORMS PROBABLY BEING AT LEAST NEAR SEVERE. THUS FAR STORMS HAVEMORPHED INTO MORE OF A NON-DISCRETE MODE WHICH MAY AID IN THAT ATLEAST INTO NORTH CENTRAL ILLINOIS. THE LINE-ECHO WAVE PATTERNSIGNATURES AND OCCASIONAL TORNADO THREATS WILL PROBABLY CONTINUETO AT LEAST NEAR THE INTERSTATE 39 CORRIDOR IN NORTH CENTRALILLINOIS...AND MAYBE A LITTLE FURTHER EAST. HIGH DYNAMIC / LOWINSTABILITY EVENTS CAN OUTPERFORM ON THAT TORNADO THREAT...BUT ITSEEMS LIKE THE DRYLINE IS FORECAST TO CATCH UP TO THEDRYLINE...AND THAT GRADUALLY IS HAPPENING ON OBSERVATIONALTRENDS...WHICH SHOULD LIMIT THE EFFECTIVE HELICITY VALUES FURTHEREAST OF I-39 TOWARD THE CHICAGO METRO.ALSO...NEAR THE COLD FRONT...WHICH IS ABOUT A COUPLE HOURS BEHINDTHE DRYLINE...THERE ARE INDICATIONS ON RAP AND NAM FORECASTPROFILES THAT ENOUGH INSTABILITY IS PRESENT TO DEVELOP SOMESHOWERS OR EVEN STORMS ON THIS. THE HRRR HAS TRENDED THIS ROUTETOO. IF SOME CELLS CAN DEVELOP IN THAT LOCATION...BASICALLYBETWEEN 11 PM AND 3 AM OR SO...CONCERNED ANY OF THOSE COULDPRODUCE SEVERE GUSTS AS WELL.OBSERVATIONAL TRENDS UPSTREAM AND CONTINUED RAP SOUNDINGS INDICATEWIND GUSTS OVERNIGHT WITHIN THE DRY SLOT AND STEEPENING LOW-LEVELLAPSE RATES SUPPORT A PERIOD OF WIND GUSTS IN EXCESS OF 50 MPH.HIGH WIND PARAMETERS AND PRESSURE CHANGE MAGNITUDE SUPPORTINCREASING FORECAST WIND GUSTS DURING THAT TIME...DESPITE THEOVERNIGHT TIMING. WITH SUCH DEEP SYNOPTIC SYSTEMS ESPECIALLY THISTIME OF YEAR...TIME OF DAY/INSTABILITY MATTERS MUCH LESS.MTF Link to comment Share on other sites More sharing options...
Gilbertfly Posted November 12, 2015 Share Posted November 12, 2015 new warning west of Peoria for gusts to 70 mph Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted November 12, 2015 Share Posted November 12, 2015 Tornado Watch expanded per Dixon, IL WR Station. Link to comment Share on other sites More sharing options...
Geos Posted November 12, 2015 Share Posted November 12, 2015 Southeast winds really sucking in dry air in northeast IL...dews have actually fallen back into the low/mid 40s in most of that area. Fallen here I know; 46°. Winds sustained at 20mph here now. Gusts to 31mph so far. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted November 12, 2015 Share Posted November 12, 2015 Severe Thunderstorm Watch per IL NWR. The storm near Scott IL which lost it's warning needs to be reissued. Link to comment Share on other sites More sharing options...
IllinoisWedges Posted November 12, 2015 Share Posted November 12, 2015 Watch just issued: http://www.spc.noaa.gov/products/watch/ww0536.html Link to comment Share on other sites More sharing options...
TimChgo9 Posted November 12, 2015 Share Posted November 12, 2015 Watch issued for LOT CWA. Link to comment Share on other sites More sharing options...
Powerball Posted November 12, 2015 Share Posted November 12, 2015 Dryline is making it pretty far east. It's cutting the western third of Missouri, while the cold front appears to be in east Kansas still It would be very nice if we could get a system like this in December / January / February over Cleveland or Columbus... Link to comment Share on other sites More sharing options...
Gilbertfly Posted November 12, 2015 Share Posted November 12, 2015 Quite a few showers/thunder popping up across N IL...see if we can pull down some of these winds aloft Link to comment Share on other sites More sharing options...
IllinoisWedges Posted November 12, 2015 Share Posted November 12, 2015 Kinda off topic, but this was one of the tornadoes in Iowa today: https://www.facebook.com/keith.siebels/videos/1053453488009321/ Friend and I thought it semi-resembled Washington. Storms out ahead of the line now have some special weather statements on them for 50-55 MPH winds and hail. Link to comment Share on other sites More sharing options...
cyclone77 Posted November 12, 2015 Share Posted November 12, 2015 Getting some 45mph southeasterly gusts with this weak cell. Can't imagine how much fun the strong ones are. Pretty impressive. Link to comment Share on other sites More sharing options...
IllinoisWedges Posted November 12, 2015 Share Posted November 12, 2015 Kinda surprised those storms over Clinton don't have a warning on them. Looks like they have some pretty strong winds. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted November 12, 2015 Share Posted November 12, 2015 Aww... none of the 00z soundings are especially interesting Link to comment Share on other sites More sharing options...
IllinoisWedges Posted November 12, 2015 Share Posted November 12, 2015 Let's not go that far... lol, even though I missed it. Surprised there's lightning, as many people thought there wouldn't be much. Best lightning here in central Rockford of the season. Better than Rochelle tornado. Car alarms going off. Link to comment Share on other sites More sharing options...
Geos Posted November 12, 2015 Share Posted November 12, 2015 Good point about the trees KRFD. Power outages should be kept down for that reason. Storms starting to pop ahead of the main line. Link to comment Share on other sites More sharing options...
cyclone77 Posted November 12, 2015 Share Posted November 12, 2015 Wow. Getting 55-60mph gusts now. Extremely impressive. Been going on several minutes. Best winds here in a long time. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted November 12, 2015 Share Posted November 12, 2015 The cells ahead of the main line are exploding rapidly, trying to get severe. Main line trying to reform. Link to comment Share on other sites More sharing options...
IllinoisWedges Posted November 12, 2015 Share Posted November 12, 2015 Line just went warned again. Woo. Link to comment Share on other sites More sharing options...
Hoosier Posted November 12, 2015 Share Posted November 12, 2015 Line of warnings now from southern WI to central IL. Link to comment Share on other sites More sharing options...
Geos Posted November 12, 2015 Share Posted November 12, 2015 RPJ just had a gust to 48 mph out of the SSE. Gusting around 35mph here now. Link to comment Share on other sites More sharing options...
hm8 Posted November 12, 2015 Share Posted November 12, 2015 Likin' the multiple embedded bows structure the line has going Link to comment Share on other sites More sharing options...
cyclone77 Posted November 12, 2015 Share Posted November 12, 2015 nice! look forward to your storm report 54mph on the weather station that's only 5ft off the ground lol. The winds gusted over 50mph for several minutes. Just roared out there. At first it was from the southeast, and then quickly swung around to the southwest and continued to be just as gusty. I wouldn't be surprised if it hit over 60mph around the neighborhood if you had a station at every house. Power went out for a bit. Surprised it's back on now actually. Link to comment Share on other sites More sharing options...
Natester Posted November 12, 2015 Share Posted November 12, 2015 I had a couple of really nasty wind gusts just after the line of storms cleared my area. All is calm right now until later tonight when the gradient winds start. Really surprised that this line (or derecho) is still intact and going on strong. Did the models have the line surviving this long? Link to comment Share on other sites More sharing options...
kevlon62 Posted November 12, 2015 Share Posted November 12, 2015 Watching some war of the worlds style high vis, low precip cgs west of Woodstock. Dry here so far. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted November 12, 2015 Author Share Posted November 12, 2015 Several CG's here with the storm that just moved overhead. Link to comment Share on other sites More sharing options...
Chicago Storm Posted November 12, 2015 Share Posted November 12, 2015 This LEWP is actually persisting even with little in the way of SBCAPE, <20J/KG per 0z soundings. However, there is MUCAPE of 250-550 over the area, which combined with the strong flow/shear, appears to be enough right now to sustain the line. If there was even just a bit more instability and moisture, no doubt things would be even more significant right now. I'd say there's 5 areas of interest that would be of concern for tornadoes in the line of that we're the case. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted November 12, 2015 Share Posted November 12, 2015 Storm near DuPage is really starting to kick up. Link to comment Share on other sites More sharing options...
hm8 Posted November 12, 2015 Share Posted November 12, 2015 wrapped up Link to comment Share on other sites More sharing options...
Hoosier Posted November 12, 2015 Share Posted November 12, 2015 LLJ ramping up now. No sign of the line breaking into more discrete cellular structures at this point. Link to comment Share on other sites More sharing options...
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