tornadotony Posted July 31, 2012 Share Posted July 31, 2012 The GFS and the Euro are in fairly good agreement about a potent shortwave trough impacting the Lakes region on Saturday. It's far too early to get to specifics, but with the amount of shear progged over the region and August-like moisture/instability likely in place, a fairly significant threat may evolve. Link to comment Share on other sites More sharing options...
wxman1952 Posted July 31, 2012 Share Posted July 31, 2012 I'll be watching. Link to comment Share on other sites More sharing options...
Stebo Posted July 31, 2012 Share Posted July 31, 2012 I think this could extend into Sunday as well especially for Eastern MI. Link to comment Share on other sites More sharing options...
wisconsinwx Posted August 1, 2012 Share Posted August 1, 2012 Andyhb, how does the 0z GFS look for severe potential? I know it cranks out some convection in S Wisconsin and N Illinois, a little further south than it has the last few runs. However, I don't have access to CAPE, shear just yet. Link to comment Share on other sites More sharing options...
cyclone77 Posted August 1, 2012 Share Posted August 1, 2012 Still looks pretty impressive. Would think it would be enough to get SPC to outline a day4 threat later on tonight. Link to comment Share on other sites More sharing options...
andyhb Posted August 1, 2012 Share Posted August 1, 2012 Got my new avatar of the 240 kt+ couplet east of Tuscaloosa... Your best chance is probably Friday night, through the day Saturday wisconsin, right now the timing for the state is not ideal. Although there definitely is also potential Saturday with the frontal passage. GFS QPF forecast for 96 hrs is actually quite interesting, fwiw... Link to comment Share on other sites More sharing options...
wisconsinwx Posted August 1, 2012 Share Posted August 1, 2012 Still looks pretty impressive. Would think it would be enough to get SPC to outline a day4 threat later on tonight. Thanks, although I noticed the low is actually way up in Ontario. It clearly seems like there is a fair amount of forcing anyway, but it concerns me that the low is that far removed from the convection. Link to comment Share on other sites More sharing options...
andyhb Posted August 1, 2012 Share Posted August 1, 2012 Plus veering LL winds = no bueno. Either way, this shortwave is definitely rather impressive for early August, I know the MPX office has gone quite bullish with their wording... GRB, MKX and ARX have all mentioned svr in some form in their AFD's. Link to comment Share on other sites More sharing options...
cyclone77 Posted August 1, 2012 Share Posted August 1, 2012 Bulk shear values still pretty decent. Not very impressed with tornado probabilities, but the general severe threat looks pretty good to me. Good forcing, good instability, good surface convergence, and nice theta-e feed paint a widespread severe threat IMO. Link to comment Share on other sites More sharing options...
andyhb Posted August 1, 2012 Share Posted August 1, 2012 Better tornado threat is likely over Minnesota on Friday, in the presence of a backed low level wind field. Link to comment Share on other sites More sharing options...
PatrickSumner Posted August 1, 2012 Share Posted August 1, 2012 How is Sunday looking for those in the IND, IWX, ILN, and LMK CWA's? Link to comment Share on other sites More sharing options...
andyhb Posted August 1, 2012 Share Posted August 1, 2012 How is Sunday looking for those in the IND, IWX, ILN, and LMK CWA's? Too far south for any real significant threat. Link to comment Share on other sites More sharing options...
StormDude81 Posted August 1, 2012 Share Posted August 1, 2012 Sunday looks like have a good chance of severe storms for the Ohio Valley into Northeast Link to comment Share on other sites More sharing options...
Hoosier Posted August 1, 2012 Share Posted August 1, 2012 Too far south for any real significant threat. I had a feeling you might say that. I may check it out anyway just for practice. Been a looong time since I have looked at a severe setup in detail. Link to comment Share on other sites More sharing options...
aurora Posted August 1, 2012 Share Posted August 1, 2012 12z GFS definitely looks favorable for a squall line in Wisconsin on Saturday. Link to comment Share on other sites More sharing options...
WolfSpider Posted August 2, 2012 Share Posted August 2, 2012 The latest NAM shows some decent severe potential in northern Illinois. Link to comment Share on other sites More sharing options...
wisconsinwx Posted August 2, 2012 Share Posted August 2, 2012 Day 3 slight risk for Eastern Wisconsin, just like Monday, but I'm bracing for and expecting a slower trend in the frontal passage, so I think this is more of a Central or even Western Wisconsin threat. Might expand east overnight, but it seems halfway inevitable the models will slow this down. Link to comment Share on other sites More sharing options...
IWXwx Posted August 2, 2012 Share Posted August 2, 2012 IWX is liking the chance of some strong/severe storms with the frontal passage for Northern IN Saturday night/Sunday morning. They are biting on the more "active" Euro, portraying increasing bulk shear and 2-3 K of CAPE. SPC naso much. I'm not liking the timing for our area, but August is usually good for a round or two of nocturnal fun. At least it's something to watch other than the thermometer. Link to comment Share on other sites More sharing options...
Boogieman Posted August 2, 2012 Share Posted August 2, 2012 DTX doesn't appear to be embracing the thought of any severe threats: HWODTX HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 407 AM EDT THU AUG 2 2012 MIZ047>049-053>055-060>063-068>070-075-076-082-083-030815- MIDLAND-BAY-HURON-SAGINAW-TUSCOLA-SANILAC-SHIAWASSEE-GENESEE-LAPEER- ST. CLAIR-LIVINGSTON-OAKLAND-MACOMB-WASHTENAW-WAYNE-LENAWEE-MONROE- 407 AM EDT THU AUG 2 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST MICHIGAN. .DAY ONE...TODAY AND TONIGHT THERE IS A CHANCE OF THUNDERSTORMS THROUGH TONIGHT AS A WEAK COLD FRONT DROPS SOUTHWARD THROUGH THE STATE. ALTHOUGH SEVERE WEATHER IS NOT EXPECTED...ANY STORMS THAT ARE ABLE TO FORM WILL BE CAPABLE OF BRIEF HEAVY DOWNPOURS AND WIND GUSTS TO 40 MPH. STORM MOTION WILL BE SOUTHEAST AT 25 MPH. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY A SERIES OF LOW PRESSURE SYSTEMS WILL PRODUCE ACTIVE WEATHER THROUGH THE WEEKEND. THE WEAK COLD FRONT MENTIONED ABOVE WILL STALL OVER SOUTHERN MICHIGAN BRINGING A CHANCE OF THUNDERSTORMS ON FRIDAY. THIS WILL BE FOLLOWED BY A SECOND STRONGER COLD FRONT SATURDAY NIGHT AND SUNDAY THAT WILL ALSO BRING A CHANCE OF THUNDERSTORMS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT. Link to comment Share on other sites More sharing options...
Hoar_Frost Posted August 2, 2012 Share Posted August 2, 2012 Shear for this set-up seems a bit on the anemic side (with the Euro offering the best and deepest shear), basically because the upper-level support via the jet stream will be pretty far north of this area. This factor is a minus for tornadoes (c'mon, it's August) and organization. However, the shortwave trough and surface cold front are pretty potent for this time of year and are superimposed on a warm, moist airmass, and this may be enough to provide for organization into a respectable squall line over northern Illinois by around early evening on Saturday. Strong winds and hail -- and yes, some rain -- may be the things to watch for during this period. My confidence is medium to high for an event sufficient to disrupt outdoor activities and only medium for severe weather. Link to comment Share on other sites More sharing options...
YHM Supercell Posted August 2, 2012 Share Posted August 2, 2012 What do you guys think for Southern Ontario around Toronto/Hamilton on Sunday? Link to comment Share on other sites More sharing options...
OntarioChaser Posted August 3, 2012 Share Posted August 3, 2012 Looks good for a possibly damaging mid day squall line Link to comment Share on other sites More sharing options...
YHM Supercell Posted August 3, 2012 Share Posted August 3, 2012 Looks good for a possibly damaging mid day squall line NAM hints at that big time. Was wondering what the mets think though. Link to comment Share on other sites More sharing options...
StormDude81 Posted August 3, 2012 Share Posted August 3, 2012 Saturady looks like a wind damage day for the midwest , and Sunday looks like a potential tornado day for East OH/Ontario/West PA/NY Link to comment Share on other sites More sharing options...
YHM Supercell Posted August 3, 2012 Share Posted August 3, 2012 Sunday's greatest threat in my opinion is damaging winds. The available shear and wind profiles really support it. Along with the available instability. A squall line is likely to set up. Who knows if some sups could get going though... Link to comment Share on other sites More sharing options...
Stebo Posted August 3, 2012 Share Posted August 3, 2012 Shear for this set-up seems a bit on the anemic side (with the Euro offering the best and deepest shear), basically because the upper-level support via the jet stream will be pretty far north of this area. This factor is a minus for tornadoes (c'mon, it's August) and organization. However, the shortwave trough and surface cold front are pretty potent for this time of year and are superimposed on a warm, moist airmass, and this may be enough to provide for organization into a respectable squall line over northern Illinois by around early evening on Saturday. Strong winds and hail -- and yes, some rain -- may be the things to watch for during this period. My confidence is medium to high for an event sufficient to disrupt outdoor activities and only medium for severe weather. The one plus side with respect to the stronger shear that the Euro shows is that the NAM also is in agreement of stronger shear arriving after 00z Sunday for WI/IL/IN/MI as the LLJ gets cranking, the GFS is on an island with respect to the lack of shear plus how much confidence can you have in a model when it is showing a completely incorrect thermodynamic profile. Link to comment Share on other sites More sharing options...
wisconsinwx Posted August 3, 2012 Share Posted August 3, 2012 The one plus side with respect to the stronger shear that the Euro shows is that the NAM also is in agreement of stronger shear arriving after 00z Sunday for WI/IL/IN/MI as the LLJ gets cranking, the GFS is on an island with respect to the lack of shear plus how much confidence can you have in a model when it is showing a completely incorrect thermodynamic profile. Is that part of the reason the GFS has shifted drier with the frontal passage? Before it was showing Euro and NAM-esque amounts (around half an inch for many), but now it is one or two tenths inches for the majority of the region Saturday. Link to comment Share on other sites More sharing options...
Stebo Posted August 3, 2012 Share Posted August 3, 2012 Is that part of the reason the GFS has shifted drier with the frontal passage? Before it was showing Euro and NAM-esque amounts (around half an inch for many), but now it is one or two tenths inches for the majority of the region Saturday. It has like no LLJ, and barely any moisture transport up here. Plus I have to believe it is too low on the temps at 850/surface, although surprisingly the dewpoints at the surface aren't too unrealistic for once. Link to comment Share on other sites More sharing options...
magoos0728 Posted August 3, 2012 Share Posted August 3, 2012 New roof going up on Saturday...hope things hold off until the evening hours here in Kenosha... Link to comment Share on other sites More sharing options...
Stebo Posted August 3, 2012 Share Posted August 3, 2012 Considerable change from the Day 3 to the new Day 2 ...GREAT LAKES REGION/MIDWEST TO LOWER MO/MIDDLE MS VALLEYS... WHILE SOME GUIDANCE VARIABILITY EXISTS...AND THERE ARE UNCERTAINTIES REGARDING THE DETAILS OF REMNANT OVERNIGHT/EARLY DAY CONVECTION INTO SATURDAY ACROSS THE UPPER MIDWEST...REASONABLE CONFIDENCE EXISTS FOR SEVERE TSTMS ACROSS THE REGION ESPECIALLY SATURDAY AFTERNOON/NIGHT. AIDED BY THE LARGE SCALE SCENARIO AS PREVIOUSLY DESCRIBED /CONSIDERABLE UPPER TROUGH/...STORMS ARE LIKELY TO DIURNALLY INCREASE/INTENSIFY INITIALLY ACROSS THE UPPER MS RIVER VALLEY TO LOWER MO/MIDDLE MS RIVER VALLEYS SATURDAY AFTERNOON. A CORRIDOR OF MODERATE TO STRONG DESTABILIZATION SEEMS LIKELY TO OCCUR SATURDAY AFTERNOON AHEAD OF AN EAST-SOUTHEASTWARD MOVING COLD FRONT. THE STRONGEST WINDS ALOFT/VERTICAL SHEAR WILL TEND TO INITIALLY LAG THE COLD FRONT IN MOST AREAS...BUT ANTICIPATED INSTABILITY/STRENGTHENING VERTICAL SHEAR WILL SUPPORT SUSTAINED MULTICELLS WITH THE POSSIBILITY OF SOME SUPERCELLS...WITH DAMAGING WINDS/SEVERE HAIL POSSIBLE. IT IS CONCEIVABLE THAT STORMS COULD FURTHER INCREASE INTO SATURDAY NIGHT...AT LEAST IN TERMS OF NUMBER/ORGANIZATION...PARTICULARLY ACROSS THE LAKE MI VICINITY INCLUDING EASTERN WI/NORTHERN IL INTO LOWER MI/INDIANA AND PERHAPS OH. NOCTURNALLY AIDED BOUNDARY LAYER INHIBITION SHOULD BE OFFSET BY APPRECIABLY STRENGTHENING DEEP FORCING FOR ASCENT/LOW TO MID TROPOSPHERIC FLOW AS THE PARENT SYSTEM AMPLIFIES AND TAKES ON A MORE NEUTRAL TILT. THIS INCREASE IN FORCING/VERTICAL SHEAR MAY CONTRIBUTE TO THE DEVELOPMENT AND SUSTENANCE OF ONE /OR MORE/ MCS/S SATURDAY NIGHT...WITH AT LEAST AN ISOLATED DAMAGING WIND POTENTIAL CONTINUING/SPREADING EASTWARD THROUGH THE NIGHT. Much more realistic sounding outlook than the low ball that was put out yesterday. Link to comment Share on other sites More sharing options...
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