A-L-E-K Posted October 16, 2012 Share Posted October 16, 2012 The main october thread is a bit of a mess and this event looks interesting enough to warrant a thread. LOT THE SPREAD IN MODELGUIDANCE HAS GROWN CONSIDERABLY SMALLER WITH RESPECT TO THE HANDLING OF THE UNUSUALLY DEEP/COLD UPPER LOW...WITH 500MB TEMPS IN THE HEART OF THE COLD POOL PROGGED TO APPROACH -30C WHICH IS RESPECTABLE FOR THE DEAD OF WINTER LET ALONE MID OCTOBER. I expect pop-up coverage to be pretty good thursday evening and friday afternoon. LOT has hail in my point for Thurs and Friday. Link to comment Share on other sites More sharing options...
Geos Posted October 16, 2012 Share Posted October 16, 2012 I don't see hail in my point, but I read it in the discussion. Wish the overnight lows were a bit colder - would make things more interesting! Link to comment Share on other sites More sharing options...
Hoosier Posted October 16, 2012 Share Posted October 16, 2012 The 00z Euro/GFS are progging peak 500 mb negative height anomalies of over 300 meters. Pretty impressive. With freezing levels falling to 3-5 thousand feet across the region, it shouldn't be too difficult to get hail to survive to the ground. Link to comment Share on other sites More sharing options...
Hoosier Posted October 16, 2012 Share Posted October 16, 2012 This setup is not that far off from being able to mix in some snow. Right now appears a little too warm but maybe some wet flakes could mix in somewhere during a heavier burst of precip. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 16, 2012 Author Share Posted October 16, 2012 This setup is not that far off from being able to mix in some snow. Right now appears a little too warm but maybe some wet flakes could mix in somewhere during a heavier burst of precip. models continue to paint pretty good QPF under the cold core...I think coverage should be pretty good and possibly intense if there's enough sun. Frozen precip should be rather widespread. Link to comment Share on other sites More sharing options...
IWXwx Posted October 16, 2012 Share Posted October 16, 2012 models continue to paint pretty good QPF under the cold core...I think coverage should be pretty good and possibly intense if there's enough sun. Frozen precip should be rather widespread. IWX mentioned it in their morning discussion. VERY COLD MID LEVEL TEMPERATURES WILL BE OVER THE AREA THURSDAY. CAN NOT RULE OUT A RAIN/SNOW OR RAIN/SLEET MIX DURING THIS TIME...BUT FOR NOW KEPT ALL PRECIPITATION AS RAIN. LOW LEVEL THICKNESSES SHOULD REMAIN ABOVE 1325 METERS. Link to comment Share on other sites More sharing options...
Geos Posted October 16, 2012 Share Posted October 16, 2012 Early Friday morning a pocket of 0°-2.5°C air at 925mb level passes over this area. Edit: Skilling mentioned the threat for waterspouts will be high under the cutoff. Link to comment Share on other sites More sharing options...
Powerball Posted October 16, 2012 Share Posted October 16, 2012 With the exception of Octobomb, nothing's fun about a cut-off low in October. Link to comment Share on other sites More sharing options...
Geos Posted October 17, 2012 Share Posted October 17, 2012 Latest disco on cutoff from LOT: THURSDAY THROUGH SATURDAY... ANOMALOUSLY STRONG SHORTWAVE WILL STEADILY PUSH SOUTHEAST ACROSS THE GREAT LAKES REGION...WITH VERY COLD AIR ALOFT ASSOCIATED WITH THIS FEATURE. TEMPS AT 850MB THUR WILL STRUGGLE TO WARM BEYOND 0 DEG C. THE GREATEST CONCERN FOR THUR AFTN WILL BE THE POTENTIAL FOR LOW-TOPPED CONVECTION THAT MAY GENERATE SOME SMALL HAIL...GRAUPEL...GIVEN THE STRONG THERMAL DIFFERENTIAL EXPECTED FROM THE SFC TO TEMPS ALOFT. THIS SCENARIO COULD BECOME ENHANCED WITH ANY BREAKS IN THE CLOUDS DURING THE DAY...WHICH WOULD ALLOW EVEN STRONGER DIFFERENTIAL HEATING TO OCCUR FROM THE SFC TO TEMPS ALOFT. ENSEMBLES INDICATE THE STRENGTH OF THE 500MB TROUGH AT 5 SIGMA BELOW NORMAL...WHICH IS RATHER SIGNIFICANT GIVEN FALL SYSTEMS LIKE THIS TEND TO BE NORMAL. AFTERNOON TEMPS THUR WILL MAINLY BE IN THE LOW 50S...HOWEVER COULD SEE A FEW LOCATIONS ALONG AND NORTH OF I-88 STAYING IN THE UPR 40S. FOR FRI A VERY SIMILAR SETUP WILL OCCUR...NEARLY IDENTICAL TO THUR. THE ONLY DIFFERENCE COULD BE THAT THE POTENTIAL FOR CONVECTION DOES NOT APPEAR TO BE AS HIGH. TEMPS MAY ALSO WARM A FEW DEGREES FROM THE LOW 50S...PUSHING TO THE MID 50S. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 17, 2012 Author Share Posted October 17, 2012 0z NAM looks fun Link to comment Share on other sites More sharing options...
Hoosier Posted October 17, 2012 Share Posted October 17, 2012 0z NAM looks fun Always fun seeing a low do a counterclockwise loop. Link to comment Share on other sites More sharing options...
Geos Posted October 17, 2012 Share Posted October 17, 2012 This is looking more interesting. Just spins to our west and sets up rain bands across the western Lakes. Leaves for time for waterspout conditions over the lakes. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted October 17, 2012 Share Posted October 17, 2012 To me the models have really changed their tune since the 12z runs and now show a much stronger wave crossing the rockies digging into the plains at the big of this big upper level low then swinging northeast into this area setting off the heavy rain tomorrow night. The 0z NAM gets the sfc low down to 989mb. Haven't looked in detail yet on the thermal profiles of these runs. Link to comment Share on other sites More sharing options...
IWXwx Posted October 17, 2012 Share Posted October 17, 2012 This thing's gonna fujiwara all over itself. Not a pretty sight, unless you like a cold rain. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 17, 2012 Author Share Posted October 17, 2012 This thing's gonna fujiwara all over itself. Not a pretty sight, unless you like a cold rain. I think we'll see enough breaks to set off low top convection thurs/fri Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 17, 2012 Author Share Posted October 17, 2012 6z NAM with a stripe of 3"+ through Geos land Link to comment Share on other sites More sharing options...
Geos Posted October 17, 2012 Share Posted October 17, 2012 6z NAM with a stripe of 3"+ through Geos land Just a touch west of me. Phil Schwartz showing about the same map a little while ago. Fox Valley does really well and over to the lake front. 12z run not nearly as wet. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 17, 2012 Author Share Posted October 17, 2012 Just a touch west of me. Phil Schwartz showing about the same map a little while ago. Fox Valley does really well and over to the lake front. 12z run not nearly as wet. 3" was clearly an outlier but a widespread .50" event with isolated amounts to an inch sounds about right. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 17, 2012 Author Share Posted October 17, 2012 micro cell just passed over my apartment and precip starting to breakout downstate Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 17, 2012 Author Share Posted October 17, 2012 WITH THEAPPROACH OF A FAIRLY STOUT VORT LOBE OUT AHEAD OF THIS DIGGING TROUGH...FORCING WILL REALLY RAMP UP. THIS WILL HELP AN EXPANDING AREA OF PRECIP TO SPREAD NORTHEAST ACROSS THE ENTIRE CWA LATE THIS AFTERNOON THROUGH THE EVENING. SEVERAL FORCING MECHANISMS WILL COME TOGETHER DURING THIS TIME FRAME AND PROVIDE STRONG FORCING TO OCCUR OVERHEAD. WITH THIS STRONG FORCING COINCIDING WITH AN INCREASE IN MOISTURE...LINGERING WEAK INSTABILITY...AND AN INCREASE IN BULK SHEAR...HAVE BECOME A LITTLE MORE CONCERNED WITH THUNDERSTORM POTENTIAL. ALTHOUGH THUNDERSTORMS WILL BE POSSIBLE ACROSS THE ENTIRE CWA THIS AFTERNOON...PREVIOUS THINKING CONTINUES WITH THE BETTER CHANCES FOR THUNDERSTORMS APPEARING TO BE SOUTH OF INTERSTATE 80 LATE THIS AFTERNOON AND EVENING WITH A FEW POSSIBLY BECOMING STRONG TO SEVERE...WITH STRONG WINDS THE PRIMARY CONCERNS. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted October 17, 2012 Share Posted October 17, 2012 lots of lightning with the storms along/south of I-80. IKK southwest to BMI/PIA. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 17, 2012 Author Share Posted October 17, 2012 Coverage expanding nicely into the city Link to comment Share on other sites More sharing options...
Thunder Road Posted October 17, 2012 Share Posted October 17, 2012 several flashes/rumbles here at Valpo in the last 10-15 minutes. Link to comment Share on other sites More sharing options...
Thunder Road Posted October 18, 2012 Share Posted October 18, 2012 Radar suggests the squall line is holding its own through IL, although the obs are not all that impressive. 21 kts at AAA, 33 kts at BMI, 33 kts at DEC maybe at least some thunder along with the heavy rain later on this evening Link to comment Share on other sites More sharing options...
Chicago WX Posted October 18, 2012 Share Posted October 18, 2012 Good enough lightning show here/to my west. Seems like it's been awhile. Link to comment Share on other sites More sharing options...
Chicago Storm Posted October 18, 2012 Share Posted October 18, 2012 1000 PM NON-TSTM WND GST 4 NE CHICAGO 41.92N 87.57W 10/17/2012 M61 MPH LMZ741 IL C-MAN STATION Link to comment Share on other sites More sharing options...
hm8 Posted October 18, 2012 Share Posted October 18, 2012 Couple rumbles of thunder mixed in here Link to comment Share on other sites More sharing options...
RobertSul Posted October 18, 2012 Share Posted October 18, 2012 Woke up to a very loud crack of thunder at around 1:30am. My first reaction? To swing at the air. Definitely the loudest thunder I've heard all year. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 18, 2012 Author Share Posted October 18, 2012 good sun over the city for the time being Link to comment Share on other sites More sharing options...
hm8 Posted October 18, 2012 Share Posted October 18, 2012 Around .6" of rain here so far. Link to comment Share on other sites More sharing options...
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