Roger Smith Posted July 17, 2012 Share Posted July 17, 2012 I didn't see a relevant thread for Tuesday's possible outbreak of severe storms in southern and central ON which may also affect parts of MI, OH and on into the next forum over (NY/PA etc). Briefly, I would expect some severe storms to race southeast across Lake Huron, southwestern and south central ON, parts of Michigan and northern OH, into the Lake Ontario region incl w and n NY. Some could be damaging with slight risk of a tornado especially in and around Toronto and within 70 miles northwest to northeast, extending on later towards Kingston ON. Will update around 10z. Link to comment Share on other sites More sharing options...
Roger Smith Posted July 17, 2012 Author Share Posted July 17, 2012 SPC have extended their slight risk zones to include parts of MI and WI. My latest analysis confirms that strong potential for severe storm development exists along a sliding cold front now located in northern WI, north-central MI into central ON. A squall-line type outbreak is possible after 4 p.m. EDT with the risk of embedded F1-F2 tornadic wind streaks. I believe the regions around Lake Huron, southern Georgian Bay, Toronto-York-Peel-Durham and all around Lake Ontario are especially at risk of damaging winds later today. Storms will have a higher than average rate of forward speed once this line gets going. Link to comment Share on other sites More sharing options...
on_wx Posted July 17, 2012 Share Posted July 17, 2012 EC pulled the severe thunderstorm watch early this morning from Michigan to Quebec and they usually don't issue early and widespread watches unless they are expecting an active day. Dave Patrick tweeted that he thinks this area may be prime for tornadic potential today, and it looks like a good chunk of the chaser community is converging on Waterloo Region and surrounding areas right now. The Weather Network's Mark Robinson is also flying down the 401 heading this way. Link to comment Share on other sites More sharing options...
on_wx Posted July 17, 2012 Share Posted July 17, 2012 Scratch that...looks like everyone is leaving this area now Link to comment Share on other sites More sharing options...
IWXwx Posted July 17, 2012 Share Posted July 17, 2012 MESOSCALE DISCUSSION 1482 NWS STORM PREDICTION CENTER NORMAN OK 1258 PM CDT TUE JUL 17 2012 AREAS AFFECTED...WI CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 171758Z - 172000Z PROBABILITY OF WATCH ISSUANCE...40 PERCENT SUMMARY...AREAS OF CNTRL AND NRN WI ARE BEING MONITORED FOR A POSSIBLE WATCH THIS AFTERNOON. LATEST INDICATIONS ARE THAT AT LEAST ISOLATED STORMS MAY DEVELOP ALONG AND NORTH OF A STALLED FRONT IN THE NEXT FEW HOURS. DISCUSSION...SURFACE ANALYSIS REVEALS A WEST-TO-EAST FRONTAL ZONE STALLED ACROSS SCNTRL WI WITH VERY WARM AND INCREASING UNSTABLE CONDITIONS DEVELOPING WITHIN A STRONGLY CAPPED AIRMASS COINCIDENT WITH THE FRONTAL POSITION. A FEW SCATTERED TSTMS CONTINUE WELL NORTH OF THE SURFACE FRONT...ACROSS NRN WI...AS PART OF A WEAK MCV THAT WAS GENERATED FROM CONVECTION ACROSS THE DAKOTAS YESTERDAY AFTERNOON. ON THE LARGE SCALE...LIFT ACROSS THE FRONTAL ZONE WILL LIKELY BE AIDED BY SLOPED ASCENT ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF A MODESTLY STRONG MID/UPPER JET SITUATED ACROSS SRN LAKE SUPERIOR. EVEN WITH THIS FAVORABLE PATTERN OF BACKGROUND ASCENT...PRONOUNCED MID LEVEL EML PLUME AND RESULTANT CAPPING WILL BE DIFFICULT TO COMPLETELY ELIMINATE TO ALLOW WIDESPREAD SURFACE-BASED STORM INITIATION...AT LEAST IN THE SHORT-TERM. HOWEVER...IT DOES APPEAR THAT ANOTHER HOUR OR TWO OF STRONG HEATING IN THE PRESENCE OF PERSISTENT LOW LEVEL CONVERGENCE AND BACKGROUND ASCENT NEAR THE BOUNDARY COULD CONTRIBUTE TO AT LEAST ISOLATED STORM DEVELOPMENT. FORECAST SHEAR PROFILES NEAR AND NORTH OF THE FRONT ARE SUPPORTIVE OF SUPERCELLS WITH SOME HAIL POTENTIAL. IF SURFACE-BASED DISCRETE STORMS CAN TAKE FORM NEAR THE FRONT AND POSSIBLY INTERACT WITH LAKE/BAY BREEZES...ENHANCED SR SHEAR COULD BRIEFLY BOOST TORNADO POTENTIAL. ANY CONVECTION ABLE TO FORM OVER THE WARM SECTOR COULD ALSO POSE A THREAT FOR DAMAGING WINDS. IF GREATER CERTAINTY REGARDING INITIATION...STORM COVERAGE AND INTENSITY IS FORTHCOMING THIS AFTERNOON...A WATCH MAY BE NEEDED ACROSS THE REGION. ..CARBIN/MEAD.. 07/17/2012 Link to comment Share on other sites More sharing options...
Roger Smith Posted July 17, 2012 Author Share Posted July 17, 2012 I continue to expect widespread severe storms in s/c ON and parts of MI, the complex in WI near Green Bay may seed this development but it may also just explode out ahead along the sliding frontal boundary. A few small cells are now visible on radar near Bad Axe MI. A separate line of storms in eastern ON between Ottawa and Kingston and heading for northern New England is tor warned at present time. This reminds me a bit of the July 15 1995 early morning derecho set-up, with the severe heat and humidity followed by an overnight fast-moving frontal wave. Ontario storm chasers should be ready perhaps for almost any deployment between Goderich and Barrie once this dormant frontal trough gets a jolt of energy around 5-7 p.m. Link to comment Share on other sites More sharing options...
RobertSul Posted July 17, 2012 Share Posted July 17, 2012 Think that developing complex up in Wisconsin will reach SE Michigan? What are the chances of a derecho forming? Link to comment Share on other sites More sharing options...
on_wx Posted July 18, 2012 Share Posted July 18, 2012 The storm coming in just got warned. Pitch black skies to the west and constant lightning. SEVERE THUNDERSTORM WARNING ISSUED BY ENVIRONMENT CANADA AT 8:25 PM EDT TUESDAY 17 JULY 2012. --------------------------------------------------------------------- SEVERE THUNDERSTORM WARNING FOR: =NEW= STRATFORD - MITCHELL - SOUTHERN PERTH COUNTY =NEW= LISTOWEL - MILVERTON - NORTHERN PERTH COUNTY =NEW= KITCHENER - CAMBRIDGE - REGION OF WATERLOO. --------------------------------------------------------------------- ==DISCUSSION== AT 8:20 PM RADAR SHOWS A STRONG TO SEVERE THUNDERSTORM NORTHWEST OF STRATFORD MOVING EASTWARD AT 40 KM/H. TORRENTIAL DOWNPOURS, LARGE HAIL, AND STRONG WINDS COULD BE ASSOCIATED WITH THIS STORM. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 18, 2012 Share Posted July 18, 2012 slight risk expanded over much of the area Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 18, 2012 Share Posted July 18, 2012 decent MCS up around the twin cities is sending a nice outflow boundary SE...might be worth watching this for development as it rides into the area. Link to comment Share on other sites More sharing options...
KokomoWX Posted July 18, 2012 Share Posted July 18, 2012 MESOSCALE DISCUSSION 1490 NWS STORM PREDICTION CENTER NORMAN OK 1138 AM CDT WED JUL 18 2012 AREAS AFFECTED...SRN MN...SWRN WI...NERN IA...NRN IL CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 181638Z - 181745Z PROBABILITY OF WATCH ISSUANCE...40 PERCENT SUMMARY...DMGG WIND AND HAIL WILL BECOME POSSIBLE THIS AFTERNOON...WITH A LOOSELY ORGANIZED CLUSTER PROGRESSING SEWD WITH TIME. AREA IS BEING MONITORED FOR A POSSIBLE WW. DISCUSSION...THE ONGOING ELEVATED THUNDERSTORMS ACROSS CNTRL/SRN MN HAS LEFT AN OUTFLOW BOUNDARY...LOCATED JUST E OF FARIBAULT MN AND EXTENDING SWWD THROUGH ALGONA IA. TWO SEPARATE BOUNDARIES ARE ALSO ORIENTED NEAR MN/WI/IA/IL...INCLUDING BUT NOT LIMITED TO A DIFFERENTIAL HEATING ZONE ACROSS CNTRL WI...AND A COLD FRONT ORIENTED ACROSS NRN IA AND IL. WITH AMBIENT MOISTURE AND SURFACE TEMPERATURES QUICKLY WARMING INTO THE 80S TO LOWER 90S F...MODIFIED MPX AND DVN SOUNDINGS INDICATE ANY REMAINING CONVECTIVE INHIBITION WILL BE ERODED SHORTLY. AS SUCH...EXPECT A GENERAL INCREASE IN CONVECTION...PARTICULARLY NEAR THE OUTFLOW/COLD FRONT INTERSECTION ACROSS SERN MN AND NERN IA. ALTHOUGH DEEP LAYER SHEAR IS WEAK...AS THE EVOLVING CLUSTER OF STORMS PROGRESSES TOWARDS THE GREAT LAKES...IT WILL ENCOUNTER LIGHT-MODEST NWLY FLOW ALOFT...SUPPORTING MULTICELLULAR CLUSTERS CAPABLE OF DMGG WIND AND HAIL. ..HURLBUT/MEAD.. 07/18/2012 ATTN...WFO...LOT...MKX...DVN...ARX...MPX...DMX... Link to comment Share on other sites More sharing options...
KokomoWX Posted July 18, 2012 Share Posted July 18, 2012 MESOSCALE DISCUSSION 1491 NWS STORM PREDICTION CENTER NORMAN OK 1154 AM CDT WED JUL 18 2012 AREAS AFFECTED...PORTIONS OF INDIANA/OH/WV TO WESTERN PA CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 181654Z - 181900Z PROBABILITY OF WATCH ISSUANCE...60 PERCENT SUMMARY...POTENTIAL FOR ISOLATED BOUTS OF DAMAGING WINDS/SOME HAIL WILL INCREASE THIS AFTERNOON ACROSS PORTIONS OF INDIANA/MUCH OF OH INTO WESTERN PA/NORTHERN WV. DISCUSSION...THE AIRMASS TO THE SOUTH OF A FRONTAL BOUNDARY...THAT EXTENDS ROUGHLY WEST-EAST FROM SOUTHERN LAKE MI VICINITY TO NEAR LAKE ERIE...HAS BECOME MODERATE TO STRONGLY UNSTABLE ACROSS BROAD PORTIONS OF INDIANA/MUCH OF OH AS WELL AS ADJACENT PARTS OF WESTERN PA/NORTHERN WV. AS SURFACE TEMPERATURES CONTINUE TO CLIMB INTO/THROUGH THE 90S F...RELATIVELY STEEP LOW-MID LEVEL LAPSE RATES AND AMPLE PRECIPITABLE WATER ENVIRONMENT ARE SUPPORTING SBCAPE VALUES TO AS HIGH AS 2500-3500 J/KG...AS PER MODIFICATIONS TO 12Z OBSERVED SOUNDINGS FROM LINCOLN IL/WILMINGTON OH/PITTSBURGH PA. WHILE STRONG UPDRAFTS/DOWNDRAFTS WILL BE POSSIBLE GIVEN THE DEGREE OF BUOYANCY/LAPSE RATES...WEAK VERTICAL SHEAR /PER WSR-88D VWPS AND AFOREMENTIONED 12Z SOUNDINGS/ MAY TEND TO LIMIT THE OVERALL ORGANIZATION. NONETHELESS...MICROBURSTS/DAMAGING WINDS...ALONG WITH SOME HAIL...WILL BE POSSIBLE WITH PULSE/MULTICELLULAR STORMS THIS AFTERNOON. A SEVERE TSTM WATCH MAY BE NEEDED THIS AFTERNOON FOR PORTIONS OF THE REGION...ESPECIALLY IF STORMS BEGIN TO CONGEAL/ORGANIZE TO A DEGREE. ..GUYER/MEAD.. 07/18/2012 ATTN...WFO...PBZ...RLX...CLE...ILN...IWX...IND... Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 18, 2012 Share Posted July 18, 2012 watches in effect all along the front now Link to comment Share on other sites More sharing options...
LizardMafia Posted July 18, 2012 Share Posted July 18, 2012 IND picked up .13" in the last hour.. So it can rain at IND.. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 18, 2012 Share Posted July 18, 2012 decent convective cluster trying to organize over the MN/IA border...would be nice to see something organized pass over N IL later and bring some rain to the nrothern tier that has been the most dry. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted July 18, 2012 Share Posted July 18, 2012 decent convective cluster trying to organize over the MN/IA border...would be nice to see something organized pass over N IL later and bring some rain to the nrothern tier that has been the most dry. Will be interesting to watch over the next few hours, lead cell riding that boundary with the cluster just behind it and things should turn southeast along instability/theta-e gradient. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 18, 2012 Share Posted July 18, 2012 Will be interesting to watch over the next few hours, lead cell riding that boundary with the cluster just behind it and things should turn southeast along instability/theta-e gradient. I get the feeling this will be to my southwest (looking better for you) but the front really isn't pushing south so who knows. Link to comment Share on other sites More sharing options...
Chicago Storm Posted July 18, 2012 Share Posted July 18, 2012 decent convective cluster trying to organize over the MN/IA border...would be nice to see something organized pass over N IL later and bring some rain to the nrothern tier that has been the most dry. Probably will have to wait and see if there is eventually further development farther south, as odds are that complex stays along/north of the IL/WI border. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted July 18, 2012 Share Posted July 18, 2012 getting better looking cu now along the boundary in southern WI. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted July 18, 2012 Share Posted July 18, 2012 MESOSCALE DISCUSSION 1494 NWS STORM PREDICTION CENTER NORMAN OK 0307 PM CDT WED JUL 18 2012 AREAS AFFECTED...SERN MN...NERN IA...SWRN WI...NRN IL CONCERNING...SEVERE THUNDERSTORM WATCH 493... VALID 182007Z - 182100Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 493 CONTINUES. SUMMARY...CONVECTIVE COVERAGE IS INCREASING ACROSS SERN MN AND NERN IA...AND MAY EVOLVE INTO AN ESEWD PROGRESSING MCS CAPABLE OF DMGG WINDS OVER THE NEXT FEW HOURS. DISCUSSION...20Z WV IMAGERY INDICATES A SUBTLE UPPER TROUGH...WITH IMPLIED FORCING FOR ASCENT AND MODEST WLY FLOW ALOFT PROGRESSING INTO MN/IA ATTM. IN COMBINATION WITH A WEAK MCV AND REMNANT OUTFLOW BOUNDARY NOTED NEAR THE N CNTRL IA/S CNTRL MN BORDER...CONVECTION IS BEGINNING TO INCREASE IN COVERAGE AND INTENSITY OVER SERN MN/NERN IA. AMBIENT MOISTURE AND DIURNAL HEATING HAVE SUPPORTED TEMPERATURES IN THE UPPER 90S TO NEAR 100 F S OF THE STATIONARY FRONT IN ADVANCE OF THE ONGOING COMPLEX. WITH THE ASSOCIATED STEEP LOW-LEVEL LAPSE RATES...THERE IS SOME POTENTIAL THAT AN ORGANIZED COLD POOL COULD DEVELOP...WITH AN ATTENDANT THREAT OF DMGG WINDS ACROSS THE WW AREA. ADDITIONAL DEVELOPMENT IS POSSIBLE ALONG THE COLD FRONT ACROSS SRN WI...WHERE CU FIELDS HAVE BECOME INCREASINGLY AGITATED. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 18, 2012 Share Posted July 18, 2012 MESOSCALE DISCUSSION 1494 NWS STORM PREDICTION CENTER NORMAN OK 0307 PM CDT WED JUL 18 2012 AREAS AFFECTED...SERN MN...NERN IA...SWRN WI...NRN IL CONCERNING...SEVERE THUNDERSTORM WATCH 493... VALID 182007Z - 182100Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 493 CONTINUES. SUMMARY...CONVECTIVE COVERAGE IS INCREASING ACROSS SERN MN AND NERN IA...AND MAY EVOLVE INTO AN ESEWD PROGRESSING MCS CAPABLE OF DMGG WINDS OVER THE NEXT FEW HOURS. DISCUSSION...20Z WV IMAGERY INDICATES A SUBTLE UPPER TROUGH...WITH IMPLIED FORCING FOR ASCENT AND MODEST WLY FLOW ALOFT PROGRESSING INTO MN/IA ATTM. IN COMBINATION WITH A WEAK MCV AND REMNANT OUTFLOW BOUNDARY NOTED NEAR THE N CNTRL IA/S CNTRL MN BORDER...CONVECTION IS BEGINNING TO INCREASE IN COVERAGE AND INTENSITY OVER SERN MN/NERN IA. AMBIENT MOISTURE AND DIURNAL HEATING HAVE SUPPORTED TEMPERATURES IN THE UPPER 90S TO NEAR 100 F S OF THE STATIONARY FRONT IN ADVANCE OF THE ONGOING COMPLEX. WITH THE ASSOCIATED STEEP LOW-LEVEL LAPSE RATES...THERE IS SOME POTENTIAL THAT AN ORGANIZED COLD POOL COULD DEVELOP...WITH AN ATTENDANT THREAT OF DMGG WINDS ACROSS THE WW AREA. ADDITIONAL DEVELOPMENT IS POSSIBLE ALONG THE COLD FRONT ACROSS SRN WI...WHERE CU FIELDS HAVE BECOME INCREASINGLY AGITATED. Nice, hoping the bolded materializes Link to comment Share on other sites More sharing options...
Thundersnow12 Posted July 18, 2012 Share Posted July 18, 2012 Nice, hoping the bolded materializes Yeah no hint of a turn southeast yet and it's still trying to get going. Two main updrafts seen from LOT 88d up that way. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted July 18, 2012 Share Posted July 18, 2012 Def a more easterly/hair south of east jog on the last few scans, few cells popping now in southern WI. Link to comment Share on other sites More sharing options...
daddylonglegs Posted July 18, 2012 Share Posted July 18, 2012 That lead cell looks to stay south of me...hopefully the one behind it makes it in here.. Link to comment Share on other sites More sharing options...
Indystorm Posted July 18, 2012 Share Posted July 18, 2012 We had a few hundredths of rain here IMBY early this afternoon. First drops in a very long time. But the storms in the area have set up boundaries which, in addition to the stationary front being so close, may serve as a royal highway for the MCS to follow se if that cold pool does develop in the LaCrosse area. 94/67 currently Link to comment Share on other sites More sharing options...
MichiganLion Posted July 18, 2012 Share Posted July 18, 2012 Fierce, fierce lightning storm --- downtown Cincinnati. Perhaps the craziest I've ever seen. Link to comment Share on other sites More sharing options...
Indystorm Posted July 18, 2012 Share Posted July 18, 2012 Fierce, fierce lightning storm --- downtown Cincinnati. Perhaps the craziest I've ever seen. That radar certainly looks intense down there. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 18, 2012 Share Posted July 18, 2012 Fierce, fierce lightning storm --- downtown Cincinnati. Perhaps the craziest I've ever seen. Sweet Link to comment Share on other sites More sharing options...
turtlehurricane Posted July 18, 2012 Share Posted July 18, 2012 Gonna start soon in Madison, lots of cells igniting ahead of the main line, especially along that old outflow boundary. I'd watch out for some weak tornadoes or funnels with the cells right on that boundary. Link to comment Share on other sites More sharing options...
turtlehurricane Posted July 18, 2012 Share Posted July 18, 2012 From rags to riches, looks like we have an intense multi-celled storm on the way. Link to comment Share on other sites More sharing options...
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