nickgrillo
EF5
SPC mentioned upgrading to a MDT if better instability can develop... The latest ETA brings in a somewhat-favorable scenerio for the Great Lakes. I am really up for a chase, so we'll see....
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8/18/04 FCST: Midwest/Great Lakes
- Thread starter nickgrillo
- Start date
Jeremy Lemanski
EF3
Nick, i read this before looking at the new day two and nearly jumped out of my chair. Thats the best news i've heard in a while.
Time to go read spc day two.
ok, read the dis. sounds like a squall/derecho type event. Not supercells but hey when there has been cool cloudy weather for the last week and a half i'll take what i can get. I remember this morning APX. said 65 knot shear near the bridge and 45knot near sag. bay. Could be interesting.
Time to go read spc day two.
ok, read the dis. sounds like a squall/derecho type event. Not supercells but hey when there has been cool cloudy weather for the last week and a half i'll take what i can get. I remember this morning APX. said 65 knot shear near the bridge and 45knot near sag. bay. Could be interesting.
Robert Dewey
EF5
LOL... I started a thread on this topic the same time you did - I deleted it though... Here is my original post -
Looks like a decent threat for severe thunderstorms tomorrow afternoon through tomorrow evening/night. Very intense low pressure system will move eastward - North of Lake Superior during the day (988MB), with a very strong front swinging through the region. Latest ETA suggests that moisture should pool along and ahead of this front, as it becomes somewhat semi-stationary. Forecast soundings from lower MI look VERY impressive as far as speed shear is concerned, with 50knts making down to 9K-10K FT... Combined with a little directional shear in the 0-3KM layer puts helicity to near 200M2/S2. Low level and bulk shear paremeters would suggest that supercells would be a very real threat, but given the fact that the upward motion is situated in a linear fashion and SFC convergence (which is also very intense) is strongly linear, storms should form into a single line (But as usual, nothing can be ruled out). ETA suggests storms will roll through southern MI between 21Z WED and 03-06Z THU from west to east (generally), with instability still at or near 1500J/KG through the night time hours, which would likely sustain a line of thunderstorms.
This event looks like it has the potential to be a hybrid derecho event (widespread wind event, containing properties of both serial and progressive events - Such as May 31 1998), given the length/strength of the forcing along the front, very intense wind fields (especially for August!), strong height falls, very strong dry air intrusion between 500-300MB... Only real thing missing is monster CAPE values.
We shall see
Robert
Looks like a decent threat for severe thunderstorms tomorrow afternoon through tomorrow evening/night. Very intense low pressure system will move eastward - North of Lake Superior during the day (988MB), with a very strong front swinging through the region. Latest ETA suggests that moisture should pool along and ahead of this front, as it becomes somewhat semi-stationary. Forecast soundings from lower MI look VERY impressive as far as speed shear is concerned, with 50knts making down to 9K-10K FT... Combined with a little directional shear in the 0-3KM layer puts helicity to near 200M2/S2. Low level and bulk shear paremeters would suggest that supercells would be a very real threat, but given the fact that the upward motion is situated in a linear fashion and SFC convergence (which is also very intense) is strongly linear, storms should form into a single line (But as usual, nothing can be ruled out). ETA suggests storms will roll through southern MI between 21Z WED and 03-06Z THU from west to east (generally), with instability still at or near 1500J/KG through the night time hours, which would likely sustain a line of thunderstorms.
This event looks like it has the potential to be a hybrid derecho event (widespread wind event, containing properties of both serial and progressive events - Such as May 31 1998), given the length/strength of the forcing along the front, very intense wind fields (especially for August!), strong height falls, very strong dry air intrusion between 500-300MB... Only real thing missing is monster CAPE values.
We shall see
Robert
Jeremy Lemanski
EF3
AHH, Why is it everytime severe weather events could happen the site i use for the eta and ruc goes down?! :x :x 
:cry:
anyone have a site i can look at to check out the eta's convective perameters for tomorrow?
:cry:anyone have a site i can look at to check out the eta's convective perameters for tomorrow?
Robert Dewey
EF5
Originally posted by Jeremy Lemanski
AHH, Why is it everytime severe weather events could happen the site i use for the eta and ruc goes down?! :x :x
LOL... What site is that?
Jeremy Lemanski
EF3
http://www.emc.ncep.noaa.gov/mmb/svrfcst/
http://maps.fsl.noaa.gov/
its a day old, the ruc went down july 30th and they still don't have it fixed at 12 hours out.
http://maps.fsl.noaa.gov/
its a day old, the ruc went down july 30th and they still don't have it fixed at 12 hours out.
Robert Dewey
EF5
When I use web graphics, I usually will use http://www.rap.ucar.edu/weather or for a decent models page - http://weather.cod.edu/forecast/
Jeremy Lemanski
EF3
thanks rob :!:
Robert Dewey
EF5
After taking a second look at the model data, I would have to say I do see some decent tornado potential over a small area - Extreme southwestern MI into northwestern IN. Plan view shows 0-3KM helicities over 350m2/s2 in that region, combined with CAPES of 2000J/KG and some decent forcing coming through around 00Z. That would probably be the beginning of any squall line or derecho activity (initiation), which is when any supercellular activity is most likely to occur.
Robert Dewey
EF5
Latest 18Z ETA is looking kind of interesting... The weak 500mb wave (evident on the 500mb vorticity fields), is a tad bit stronger, which rides just ahead of the cold front between 21Z and 03Z across lower MI. There is a slight chance that this wave could enhance low level directional shear if a SFC reflection (at least a very weak one) were to develop in response to any mesoscale features caused by the wave.
Unmodified sounding from near LAN (42.66;-83.30) indicates 3000J/KG of CAPE available by 21Z WED right before the wave crashes through (Td's are higher this go around). Wind fields will be quite strong, ETA still shows 0-3km helicity of 150-200M2/S2 across southern lower MI, but the speed shear is more impressive than the directional shear. By 03Z, LLJ kicks in with 40knts right off the deck at 2.5K FT. Forcing still looks to be strongly linear, so I expect a pretty significant line of storms to develop.
ETA also appears to be slightly faster with the front on the 18Z run compared to the 12Z run, which would be good for areas east of LAN, when the previous run had the front just clearing the region by 06Z VS. 03Z with the new run...
Unmodified sounding from near LAN (42.66;-83.30) indicates 3000J/KG of CAPE available by 21Z WED right before the wave crashes through (Td's are higher this go around). Wind fields will be quite strong, ETA still shows 0-3km helicity of 150-200M2/S2 across southern lower MI, but the speed shear is more impressive than the directional shear. By 03Z, LLJ kicks in with 40knts right off the deck at 2.5K FT. Forcing still looks to be strongly linear, so I expect a pretty significant line of storms to develop.
ETA also appears to be slightly faster with the front on the 18Z run compared to the 12Z run, which would be good for areas east of LAN, when the previous run had the front just clearing the region by 06Z VS. 03Z with the new run...
tom hanlon
EF2
I believe !!
Wishful thinking perhaps but I have not chased since the feedback of 2 weeks ago. So I will take what I can get. I will await the 6Z 1 day before picking a target.
I see an intense squall line that will be hard to chase. Perhaps tornadoes in broken segments, and bows. I just recently read this..
http://www.erh.noaa.gov/gsp/localdat/Nov11...02_Severe_2.pdf
and the
Real life study of an active squall line will at least be educational.
Squall lines = broad target range = need for recent radar data so I may try not to stray to far from a good WI-FI spot.
I fear that the Lake will have a dampening effect. Is Lake Michigan a storm killer year round or just in the spring ?
Probably take a lazy target area in NW Indiana. Diminishes Lake effect and keeps driving to a minimum.
Wishful thinking perhaps but I have not chased since the feedback of 2 weeks ago. So I will take what I can get. I will await the 6Z 1 day before picking a target.
I see an intense squall line that will be hard to chase. Perhaps tornadoes in broken segments, and bows. I just recently read this..
http://www.erh.noaa.gov/gsp/localdat/Nov11...02_Severe_2.pdf
and the
in the SPC day 2 caught my eye.
Real life study of an active squall line will at least be educational.
Squall lines = broad target range = need for recent radar data so I may try not to stray to far from a good WI-FI spot.
I fear that the Lake will have a dampening effect. Is Lake Michigan a storm killer year round or just in the spring ?
Probably take a lazy target area in NW Indiana. Diminishes Lake effect and keeps driving to a minimum.
Jeremy Lemanski
EF3
maybe someone wants to start a thread for the lower great lakes/ohio valley for friday? Look at what the northern ind. discussion had to say.
Jeremy Lemanski
EF3
Its not nearly as much of a killer now that the water has warmed into the 60s. What hurts storms in the spring is that 40 degree water temp compared to a 80 degree air temp. If there is a derecho type of event, the waters of lk mich will do little to the storms as they cross since they should be moving at a good rate.
What pops into my mind is the derecho of may 31st 98. Went over the water at 70mph, the water had no effect on it at all. If anything, the wind near the shore of lk mich would have been higher since the water offers much less friction then the land and its trees, buidings, etc .
Robert Dewey
EF5
I would wait 'til at least THU before posting a thread on that event. I looked at the 18Z ETA and see no hint of 800M2/S2 - more like 150M2/S2, with CAPEs around 3000J/KG. Setup tomorrow actually looks better to me... Anyway, the reason I would wait for a thread is because the exact location will be highly dependant on where the frontal boundary sets up, which will likely change from model run to model run (i.e. the 18Z ETA has the best setup over OH now, VS. IN)...
Jeremy Lemanski
EF3
I hope your right 8)
