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View Full Version : Tues-Thurs Jul.20-22. Isolated Tstorms


Derecho
07-19-2010, 11:11 AM
Looks like there will be the potential for isolated severe thunderstorms from tomorrow to Thursday. Southwest Ontario looks to be in the prime location for convective development, though it certainly looks like about south of a line from Parry Sound to Ottawa could see something.

For tomorrow:

DOWNSTREAM...BOTH THE NAM AND GFS SUGGEST A SIGNIFICANT SHORTWAVE
TROUGH...POSSIBLY CONVECTIVELY ENHANCED...WILL ADVECT ACROSS THE OH
VALLEY INTO NY/PA BY LATE AFTERNOON. STRONG
THUNDERSTORMS/MCS...WILL LIKELY BE ONGOING AT THE BEGINNING OF THE
PERIOD FROM PORTIONS OF NRN IL/IND INTO LOWER MI. THIS ACTIVITY
SHOULD PROGRESS TOWARD THE UPPER OH VALLEY BY EARLY
AFTERNOON...POSSIBLY EXPERIENCING NEW DEVELOPMENT ALONG CONVECTIVE
OUTFLOW AS BOUNDARY LAYER WARMS IN ADVANCE OF COMPLEX. SHORT RANGE
MODELS SUGGEST AIRMASS EAST OF THE APPALACHIANS WILL NOT BE
PARTICULARLY UNSTABLE...HOWEVER STRENGTH OF MEAN FLOW SUGGESTS
CONVECTION COULD EASILY SPREAD INTO SRN NEW ENGLAND BEFORE
WEAKENING. AT THIS TIME WILL ONLY EXTEND LOW PROBABILITIES INTO
THIS REGION...HOWEVER LATER OUTLOOKS MAY NEED TO ACCOUNT FOR THE
POSSIBILITY OF A LONGER LIVED MCS ADVECTING INTO THIS REGION.
DAMAGING WINDS ARE THE PRIMARY THREAT WITH THE OH VALLEY CONVECTION.

Derecho
07-19-2010, 11:39 AM
The SREF is indicating there is some juice in place tomorrow for possibly a couple of isolated tornadoes somewhere from Chicago to London, ON in the late afternoon through evening.

benjaminblizzard
07-19-2010, 11:55 AM
Holy wow. This is turning into an interesting week.

Derecho
07-19-2010, 12:14 PM
No longer valid.

Weak tornado parameters in place for tomorrow:
11am tomorrow http://w1.spc.woc.noaa.gov/exper/sref/gifs/2010071909/SREF_prob_combined_sigtor__f030.gif
2pm tomorrrow http://w1.spc.woc.noaa.gov/exper/sref/gifs/2010071909/SREF_prob_combined_sigtor__f033.gif
5pm tomorrow http://w1.spc.woc.noaa.gov/exper/sref/gifs/2010071909/SREF_prob_combined_sigtor__f036.gif
8pm tomorrow http://w1.spc.woc.noaa.gov/exper/sref/gifs/2010071909/SREF_prob_combined_sigtor__f039.gif
11pm tomorrow http://w1.spc.woc.noaa.gov/exper/sref/gifs/2010071909/SREF_prob_combined_sigtor__f042.gif

Derecho
07-19-2010, 12:16 PM
Holy wow. This is turning into an interesting week.

Yeah, could be several rounds of storms this week. The Day 4-8 sounds menacing for this weekend. I dedicated this threat only up until Thursday just because things could get rough by this weekend.

Raedwulf
07-19-2010, 04:34 PM
its all south of us...
..:S?

davefootball123
07-19-2010, 06:13 PM
I hope we get something. Last nites storms were ok but we need more

davefootball123
07-20-2010, 11:43 AM
Wednesday..Scattered thunderstorms are expected from southern
Ontario into northeastern regions of the province. A few of these
may approach severe limits across Eastern Ontario towards the Golden
Horseshoe in the afternoon with sizeable hail, strong winds and
Heavy downpours.
Sizeable hail. man its been a while since ive seen that one. lol

OH VALLEY TO UPSTATE NY...

BOTH THE NAM AND GFS SUGGEST A FAIRLY STRONG MID LEVEL SPEED MAX AND
ASSOCIATED SHORTWAVE TROUGH WILL RACE ACROSS THE GREAT LAKES EARLY
IN THE PERIOD WITH THE GFS BEING SLIGHTLY MORE PROGRESSIVE INTO
NY/PA BY 22/00Z. ALTHOUGH THE STRONGEST ASCENT WILL OVERSPREAD SRN
CANADA INTO NRN NEW ENGLAND...MID LEVEL FLOW WILL STRENGTHEN ACROSS
THE OH VALLEY ENSURING ANY STORMS THAT FORM ACROSS THIS REGION WILL
MOVE AT MODEST SPEEDS...ON THE ORDER OF 35KT. BOUNDARY LAYER
DESTABILIZATION IS THE PRIMARY QUESTION WITH THIS SHORTWAVE TROUGH.
BOTH SHORT RANGE MODELS SUGGEST CONVECTION WILL BE ONGOING AT THE
BEGINNING OF THE PERIOD FROM THE LOWER GREAT LAKES...SWWD INTO
IND/IL. IF EXTENSIVE CLOUDINESS OVERSPREADS THE OH VALLEY TOO EARLY
THEN DESTABILIZATION MAY BE REDUCED ACROSS THIS REGION. WILL
MAINTAIN 15% PROBABILITIES FOR DAMAGING WINDS BUT ANY MEANINGFUL
BOUNDARY LAYER HEATING AHEAD OF TROUGH COULD LEAD TO A MORE ROBUST
THERMODYNAMIC ENVIRONMENT MORE FAVORABLE FOR CONCENTRATED SEVERE
THUNDERSTORMS.

SPC says it a little better. Slight risk seems to clip hamilton and niagara. EDIT: also friday could be a day as the system over the central high plains makes it's way through here. May be a slight risk for friday on us tomarrow

Derecho
07-20-2010, 12:42 PM
There is quite a bit of pop ups in eastern Ontario right now.

Confusing to note: an MCC was expected to be in place over southern Ontario for most of the day dropping up to 10mm of rain. It didn't develop? Since we'll be baking in the sun all day, I wonder what that might mean about our chances of lake breeze convergent storms today?

Derecho
07-20-2010, 02:00 PM
Slight Risk tomorrow for southeastern and eastern Ontario. Looks like a similar set up to last Saturday with a midday line of storms developing and pushing eastward into NY.


...OH VLY INTO NERN STATES...
DEEP/LARGELY UNIDIRECTIONAL WLY FLOW...AND ASCENT...WILL INCREASE
OVER THE UPR OH VLY AND NERN STATES ON WED AS AFOREMENTIONED UPR
TROUGH AMPLIFIES ESE FROM THE UPR GRT LKS. WITH 500 MB WLY FLOW
EXPECTED TO BE AROUND 50 KTS ACROSS PA/NJ AND NY...AMPLE SHEAR WILL
BE PRESENT FOR SUSTAINED STORMS WITH BOWING SEGMENTS AND SUPERCELLS.
LOW LVL DESTABILIZATION IS THE MAIN UNCERTAINTY AS FAR AS SVR
POTENTIAL IS CONCERNED...GIVEN LIKELIHOOD FOR ONGOING STORM
CLUSTERS/CLOUD DEBRIS IN THE OH VLY AT THE START OF THE PERIOD. IT
DOES SEEM LIKELY...NEVERTHELESS...THAT AT LEAST A FEW POCKETS OF
STRONGER SFC HEATING WILL DEVELOP BENEATH THE STRENGTHENING UPR
FLOW/ASCENT...ESPECIALLY FROM ERN NY/WRN NEW ENGLAND SSW INTO ERN
PA/NJ AND PERHAPS MD/DE. SOME OF THESE STORMS COULD PERSIST INTO
WED NIGHT.

davefootball123
07-20-2010, 02:05 PM
Hopefully we get the heating because if we dont and get stuck in cloud cover then the storms will probabley all states side or far eastern ontario. But if it is anything like last saturday we backed in the sun until about 2 when the storms rolled in.

Derecho
07-20-2010, 09:59 PM
Weak tornado parameters are in place according to the latest 21z SREF tomorrow around 2pm for eastern Ontario.

Also, to reiterate on my earlier sentiments about tomorrow, it's still looking likely for a decent shot around midday for some thunderstorm activity for southeastern Ontario, and quite possibly...

the Niagara Peninsula. :whistling:

obwan
07-21-2010, 06:30 AM
i see lightning to my south, these storms popped up fast, wonder ho much pop they have

Derecho
07-21-2010, 11:24 AM
Severe Thunderstorm Watch posted for much of southern Ontario

davefootball123
07-21-2010, 12:36 PM
Moderate risk issued east of us

obwan
07-21-2010, 04:21 PM
Working in Niagara on the Lake I watched cumulonimbus clouds parade past much of the day. I was quite unique seeing them billow as they passed by following the line of the niagara escarpment to become training Thunderstorms state side. Driving home and passing underneath i realized the band was only about 7 Km wide and equally as impressive from the south side. Should be seeing some flood warnings in WNY soon with all that rain.
I see the severe thunderstorm watch is in effect till 8:00pm around here but not much on horizon.

DarkSky
07-21-2010, 07:18 PM
Working in Niagara on the Lake I watched cumulonimbus clouds parade past much of the day. I was quite unique seeing them billow as they passed by following the line of the niagara escarpment to become training Thunderstorms state side. Driving home and passing underneath i realized the band was only about 7 Km wide and equally as impressive from the south side. Should be seeing some flood warnings in WNY soon with all that rain.
I see the severe thunderstorm watch is in effect till 8:00pm around here but not much on horizon.

I did a quick time lapse (only over a period of about 30 mins..) http://www.youtube.com/watch?v=yLf3RUvO_q4