Tue/Jul.18, 2012 - Severe outbreak, 2 confirmed tornadoes

[Storm Chaser]

Tomorrow certainly is very interesting. Although coverage may not be the greatest, a broken line of supercells may occur. It may make for some excellent chasing opportunities tomorrow, good luck to everyone!

[harrisale]

WOW. Things are really shaping up.

EHI's of 3+ for a large area of Southern Ontario, including my home area of Guelph. Max CAPE reaching over 3000 J/KG in some areas with some good shear. 36C temperatures, surface dewpoints approaching 80. The ingredients are there for a great chase day!

Only factor may be the timing of the arrival of a cold front, which may push storms later into the evening/night.

Either way, gearing up tonight!

[davefootball123]

Parameters are quite favourable for severe storms tomorrow however the greatest risk for severe storms will be in Eastern Ontario into Southern Quebec...SREF has nice sig tors in Eastern Ontario with favourable EHI, SRH, and 0-6km shear values...When looking at high res guidance...models like the WRF-NMM and NAM-NMMB break out numerous storms in Eastern Ontario/Southern Quebec into upstate New York and Vermont where forcing along the front is greatest. Continuing the look at the high res solutions, they all leave South Central Ontario free of any convection with some storms forming in Extreme Southwestern Ontario. With that being said...given the favourable parameters, if some storms can form in South Central Ontario, they will have a lot to work with and could be very severe with very large hail and damaging winds. It all depends on if they go up or not

[Storm Chaser]

No reason why they shouldn't go up, precipitation fields on many models continue to get better...I hope something happens

[davefootball123]

GFS has backed off QPF to less than .5 inches...NAM is the odd one out like it has been all year comparing to other models. Then again these are just models. Who knows what might happen.

[davefootball123]

NWS Buffalo mentioned greatest severe threat will be from Buffalo to Rochester and areas north.

[qcstorm]

Getting excited for tomorrow, it's definitely gonna be very active in my neck of the woods. I'm sure I'll get some severe weather but I am wondering if supercells will develop. SPC has mentioned the chance for an isolated tornado. Hopefully helicity levels will be favourable and like said earlier, EHI levels will be favorable for rotation. Although I think large hail will be a secondary threat tomorrow because of the very and widespread warm/humid air mass and freezing levels occurring above 14 kilo feet. But who knows, if storm tops make it above 40 000- 45 000 feet, maybe more large hail could be expected. Finally does anyone know how many rounds of storms may affect me or really anyone east of Toronto. The models are in pretty good accordance with at least one big round of storms passing between noon and early afternoon, but after that, details are a little more blurry.

[Storm Chaser]

Besides some weak morning convection, one big round in the mid - late afternoon can be expected.

[davefootball123]

Originally Posted by Storm Chaser

Besides some weak morning convection, one big round in the mid - late afternoon can be expected.

Just better hope we don't get any cloud debris....

[qcstorm]

Cloud cover should be expected to clear up because of the low level jet stream from 850 mb of 35-50 knots. Nonetheless again these are only predictions and any morning convection is bound to bring cloud cover along with it.