WED/THURS Storm Threat

[Storm Chaser]

SPC has issued a day 5 risk area for areas of the western great lakes into MI and even northwestern OH. Models indicate we also have a good shot at severe thunderstorms wed night or thursday. Temperatures are forecast to climb into the mid 20's with sufficient cape over 1000j/kg.

[Storm Chaser]

UPDATE: Latest GFS now has 2000j/kg of CAPE or more for many areas of Southern Ontario on thursday. Shear is above 35kts in many areas also. Temps look to be 25C or greater. Timing has also gotten very good. Thursday could be our first great shot at severe weather.

[davefootball123]

Thursday is looking rather interesting. 12z GFS shows impressive MLCAPE values. 1500-2000j/kg for all of SON which is more than enough to support severe thunderstorm development. Forcing looks decent enough along the front for a possible line of thunderstorms capable of damaging winds with decent shear to support sustained updrafts. Wonder what the threat for supercells is like with this one . I will wait for the SREF to come in to get a better idea.

[DarkSky]

Thank gawd for this. It's been too darn slow around here!

[Thunderbolt]

By looking at the long range forecast, it looks like we'll be getting a chance of thunderstorms up here in northeastern Ontario too.

[davefootball123]

Model agreement has decreased significantly for the threat late this upcoming week. 12z GFS now shows the ridge flattening before the cold front reaches. That would decrease severe threat big time. Still thunder potential next week though.

[Derecho]

Almost all of Southern Ontario is under a 5% severe probability Wednesday.

...OH VALLEY AND CNTRL/ERN PORTIONS OF GREAT LAKES...

MULTICELL STORM CLUSTERS WILL LIKELY BE ONGOING WITHIN ZONE OF
ISENTROPIC ASCENT GENERALLY ALONG AND NORTH OF NEWD ADVANCING WARM
FRONT. ADDITIONAL STORMS MAY DEVELOP IN WARM SECTOR AS THE BOUNDARY
LAYER DESTABILIZES. THE OVERALL THERMODYNAMIC AND KINEMATIC
ENVIRONMENT WITH WEAK VERTICAL SHEAR APPEAR TO SUPPORT ONLY A MODEST
RISK OF SEVERE STORMS...SO WILL MAINTAIN 5% SEVERE PROBABILITIES AT
THIS TIME.

Almost all of Central & Southern Ontario are under a Slight Risk on Thursday.

...ERN PORTIONS OF CNTRL PLAINS INTO MID-UPPER MS VALLEY AND GREAT
LAKES...

ANOTHER IN A SERIES OF IMPULSES WILL EJECT NEWD INTO SRN CANADA
EARLY IN THE PERIOD. A QUASI-STATIONARY FRONT WILL PERSIST WITHIN
BROAD FETCH OF MODERATE SWLY FLOW ALOFT. THUNDERSTORMS WILL LIKELY
BE ONGOING WITHIN ZONE OF ISENTROPIC ASCENT. SOME OF THIS ACTIVITY
MAY PERSIST DURING THE DAY SUPPORTED BY SWLY LLJ THAT WILL SHIFT
NEWD IN ASSOCIATION WITH EJECTING SHORTWAVE TROUGH. WARM SECTOR
SOUTH OF THE ONGOING ACTIVITY WILL BECOME MODERATELY TO STRONGLY
UNSTABLE WITH THE STRONGEST INSTABILITY EXPECTED WITH SWWD EXTEND
INTO THE CNTRL PLAINS. A WEAK IMPULSE IS FORECAST TO EJECT NEWD
THROUGH THE CNTRL PLAINS AND ADDITIONAL STORMS MAY DEVELOP ALONG THE
BOUNDARY BY LATE AFTERNOON FROM NERN KS/SERN NEB INTO THE UPPER MS
VALLEY. VERTICAL SHEAR WILL BE SUFFICIENT FOR ORGANIZED SEVERE
STORMS WITH DAMAGING WIND AND LARGE HAIL THE PRIMARY THREATS.
ACTIVITY MAY EVOLVE INTO ONE OR MORE MCS CLUSTERS AS THEY DEVELOP
EWD DURING THE AFTERNOON AND EVENING.

[obwan]

KBUF says
"while there while be a chance for storms Wednesday night and Thursday. There will be a hightened risk for strong to severe storms on Friday."

Not too often buffalo gives a storm watch three days in advance,have to wait and see.

[davefootball123]

Thanks for that post Obwan, I noticed that. Im not sure if buf may be talking about the eastern 1/2 or 2/3 of their CWA. Its hard to say at this point but the SREF keeps Friday severe potential out of Ontario. The NAM is a little more favourable for Friday. Ontario will probably see back to back to back (Wednesday, Thursday, Friday) slight risk days judging by the pattern and the large degree of uncertainty that goes with it.

[Storm Chaser]

Nam also brings in much more favorable shear thurs and fri which is nice to see.