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Thanksgiving Week Severe Weather


msp

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Guess SPC wants to err on the side of caution for possible spin ups with the new tor watch for IN and MI. I would expect straight line winds to be more of a risk in this night time frame.

Agree. I think the tor threat is decreasing overall although I suppose it's non-negligible. Low level speed shear is pretty impressive.

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It will be interesting to see what the survey says tomorrow. To take high tension wires down it takes a pretty good wind, but if the towers came down with them we're approaching EF3.

We were able to watch a nice RFD punch from the office window today, it occluded a ragged wall cloud but never got any tighter than that. An off duty employee got some shots of it, so hopefully I can snag those and upload them.

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Agree. I think the tor threat is decreasing overall although I suppose it's non-negligible. Low level speed shear is pretty impressive.

Instability will be the issue up this way, as for what has already happened, even thought its only been a few tornadoes the few that have formed sound fairly significant and the pictures would agree. It only takes one tornado to have something remembered, thankfully so far it sounds like there has not been any loss of life today.

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It will be interesting to see what the survey says tomorrow. To take high tension wires down it takes a pretty good wind, but if the towers came down with them we're approaching EF3.

We were able to watch a nice RFD punch from the office window today, it occluded a ragged wall cloud but never got any tighter than that. An off duty employee got some shots of it, so hopefully I can snag those and upload them.

More of the damage will be seen tomorrow morning, but based on what i am thinking we might have 1 or 2 EF3-or possibly EF4

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Instability will be the issue up this way, as for what has already happened, even thought its only been a few tornadoes the few that have formed sound fairly significant and the pictures would agree. It only takes one tornado to have something remembered, thankfully so far it sounds like there has not been any loss of life today.

so far:

today.gif

Still can't get over how 1/7/08 was dropped as an analog event and then we get another (very likely strong) tornado today in a similar spot. Will be interesting to compare the tracks.

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so far:

today.gif

Still can't get over how 1/7/08 was dropped as an analog event and then we get another (very likely strong) tornado today in a similar spot. Will be interesting to compare the tracks.

Yeah I think that's an interesting coincidence the more interesting thing is the similar patterns too, maybe we'll have to remember this and field trip to N IL/S WI when we see it again.

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More of the damage will be seen tomorrow morning, but based on what i am thinking we might have 1 or 2 EF3-or possibly EF4

Based on the very preliminary damage reports I've heard, sounds like a likely significant tornado, possibly low end EF3. To me there just wasn't enough ingredients for EF4 today. The 0-1km shear was 35 kts, just above what is necessary for EF2+. It is surprisingly easy to completely destroy garages, corn cribs and the like with winds below EF2 strength.

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Based on the very preliminary damage reports I've heard, sounds like a likely significant tornado, possibly low end EF3. To me there just wasn't enough ingredients for EF4 today. The 0-1km shear was 35 kts, just above what is necessary for EF2+. It is surprisingly easy to completely destroy garages, corn cribs and the like with winds below EF2 strength.

Yep. The damage that sounds more interesting is with those lines/possible towers down as well as that business.

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The tornado we shot was just north of the intersection of Hunter and Ryan roads northwest of Chemung. It lifted shortly thereafter at least for a bit, perhaps dropping again in Lawrence per NWS preliminary storm reports. We got some "damage" pictures to trees and one steel highway sign post as the sun set and talked to a homeowner, who mentioned the January 2008 storm going through his yard on a very similar track. This line today was maybe 50 yards further south at least at that point, but also on the southwest to northeast trajectory. Eerily similar in the track.

I'm guessing the width was maybe twenty yards where we were. Strength of EF0.

Still having an issue uploading pics. Maybe it's my firefox.

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The tornado we shot was just north of the intersection of Hunter and Ryan roads northwest of Chemung. It lifted shortly thereafter at least for a bit, perhaps dropping again in Lawrence per NWS preliminary storm reports. We got some "damage" pictures to trees and one steel highway sign post as the sun set and talked to a homeowner, who mentioned the January 2008 storm going through his yard on a very similar track. This line today was maybe 50 yards further south at least at that point, but also on the southwest to northeast trajectory. Eerily similar in the track.

I'm guessing the width was maybe twenty yards where we were. Strength of EF0.

Still having an issue uploading pics. Maybe it's my firefox.

What about uploading to photobucket or something?

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The tornado we shot was just north of the intersection of Hunter and Ryan roads northwest of Chemung. It lifted shortly thereafter at least for a bit, perhaps dropping again in Lawrence per NWS preliminary storm reports. We got some "damage" pictures to trees and one steel highway sign post as the sun set and talked to a homeowner, who mentioned the January 2008 storm going through his yard on a very similar track. This line today was maybe 50 yards further south at least at that point, but also on the southwest to northeast trajectory. Eerily similar in the track.

I'm guessing the width was maybe twenty yards where we were. Strength of EF0.

Still having an issue uploading pics. Maybe it's my firefox.

Heck if its 50 yards away I'd consider that dead on.

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I still have to keep reminding myself that it doesn't take as much moisture / instability in the cold season to have svr wx as long as the dynamics are there than it does in the spring and summer. I broadbrush things by thinking that dews in the 50's are ok for t storms but I need dews in the 60's for tornadoes, which may work in spring and summer but not necessarily in this season.

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I still have to keep reminding myself that it doesn't take as much moisture / instability in the cold season to have svr wx as long as the dynamics are there than it does in the spring and summer. I broadbrush things by thinking that dews in the 50's are ok for t storms but I need dews in the 60's for tornadoes, which may work in spring and summer but not necessarily in this season.

Instability is always about the change in temperature and moisture with height, no matter the time of year. It's never based solely on surface conditions, and there are never magical surface thresholds. There are common ones for severe thunderstorm and tornado situations, because of the time of year most severe weather events happen... but there are never magic thresholds. If the mid-level temperatures are cold enough and the temperatures decrease rapidly enough with height, you can theoretically have 2000 j/kg of SBCAPE with temperatures in the 50s.

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I still have to keep reminding myself that it doesn't take as much moisture / instability in the cold season to have svr wx as long as the dynamics are there than it does in the spring and summer. I broadbrush things by thinking that dews in the 50's are ok for t storms but I need dews in the 60's for tornadoes, which may work in spring and summer but not necessarily in this season.

Not to drag the thread too OT but here is a case from 11/12/65 which produced several strong tornadoes in northern IL/northwest IN. Here are a couple maps courtesy of Bangladesh Tornadoes:

Surface map:

11126519zsf.gif

Fairly deep low (deeper than today at least) but the temps/dewpoints don't really jump out at you. Instability probably wasn't that high. The result?

111265pth.gif

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The tornado we shot was just north of the intersection of Hunter and Ryan roads northwest of Chemung. It lifted shortly thereafter at least for a bit, perhaps dropping again in Lawrence per NWS preliminary storm reports. We got some "damage" pictures to trees and one steel highway sign post as the sun set and talked to a homeowner, who mentioned the January 2008 storm going through his yard on a very similar track. This line today was maybe 50 yards further south at least at that point, but also on the southwest to northeast trajectory. Eerily similar in the track.

I'm guessing the width was maybe twenty yards where we were. Strength of EF0.

Still having an issue uploading pics. Maybe it's my firefox.

Here we go.

Radar capture showing approximate observed path (thin black line) and our position during the tornado.

post-855-0-35594200-1290473652.png

The wall cloud and tornado itself was well contrasted. After moving for about twenty seconds at the width in the pictures below, it did lift. Rotation with the wall cloud itself continued, although video of that did not turn out too visible, outside of rapidly moving rain curtains.

post-855-0-85333300-1290472626.jpg

post-855-0-68761200-1290472653.jpg

'Damage path' as detailed in the picture.

post-855-0-01446400-1290472700.jpg

Steel highway sign post.

post-855-0-93319700-1290472742.jpg

A closer view of the soft wood tree damage, on both edges of the field. The house I referenced from 2008 is just off the frame to the north (left) of those pines. It is late in the year and with many of the fields harvested and tilled and bare trees, there wasn't much vegetation to be pulled airborne.

post-855-0-07681500-1290472822.jpg

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MESOSCALE DISCUSSION 2066

NWS STORM PREDICTION CENTER NORMAN OK

0709 PM CST MON NOV 22 2010

AREAS AFFECTED...PORTIONS OF NRN AND CNTRL AR

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 230109Z - 230215Z

THE THREAT FOR A SEVERE STORMS CAPABLE OF HAIL...LOCALLY DAMAGING

WINDS AND PERHAPS A COUPLE OF TORNADOES APPEARS TO BE INCREASING

ACROSS THE DISCUSSION AREA AND CONVECTIVE TRENDS ARE BEING MONITORED

FOR A POSSIBLE WW.

RECENT TRENDS IN REGIONAL RADAR IMAGERY INDICATE DEEPENING

CONVECTION WITHIN PRE-FRONTAL WARM SECTOR FROM N OF HOT TO BVX. 00Z

LIT SOUNDING INDICATED THE PRESENCE OF A CAPPING INVERSION AT AROUND

720 MB. HOWEVER...SUSTAINED LOW-LEVEL CONFLUENCE AND MOISTENING

ALONG SRN EXTENSION OF SWLY 40-50 KT LLJ MAY SUPPORT EVENTUAL STORM

DEVELOPMENT WITHIN THE SW-NE ORIENTED BAND OF DEEPENING CONVECTIVE

DEVELOPMENT. THIS SCENARIO IS SUPPORTED BY LATEST MESOSCALE AND

CONVECTION-RESOLVING MODEL GUIDANCE AND GIVEN THE STRONGLY SHEARED

ENVIRONMENT /REF. 00Z LIT SOUNDING AND CURRENT VWP DATA/...THE

POTENTIAL WILL EXIST FOR SUPERCELLS CAPABLE OF A COUPLE OF TORNADOES

IN ADDITION TO DAMAGING WINDS AND HAIL.

ELSEWHERE...TSTMS DEVELOPING NEAR COLD FRONT-DRYLINE TRIPLE POINT E

OF MKO MAY CONTINUE TO INTENSIFY WHILE MOVING EWD INTO NWRN AR WHERE

ENVIRONMENT BECOMES PROGRESSIVELY MORE MOIST AND STRONGLY SHEARED IN

THE LOW-LEVELS.

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URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 748

NWS STORM PREDICTION CENTER NORMAN OK

800 PM CST MON NOV 22 2010

THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF

NORTHERN AND CENTRAL ARKANSAS

FAR EAST CENTRAL OKLAHOMA

EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 800 PM UNTIL

300 AM CST.

TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.

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URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 749

NWS STORM PREDICTION CENTER NORMAN OK

825 PM CST MON NOV 22 2010

THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF

EASTERN ARKANSAS

SOUTHERN ILLINOIS

SOUTHWEST INDIANA

WESTERN KENTUCKY

SOUTHEAST MISSOURI

NORTHWEST MISSISSIPPI

WESTERN TENNESSEE

EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 825 PM UNTIL

400 AM CST.

TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS

TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

DISCUSSION...SHOWERS/TSTMS FORMING ALONG SW-NE PREFRONTAL CONFLUENCE

ZONE...AND STORMS ALONG FRONTAL BAND FARTHER NW...EXPECTED TO

PERSIST AND POSSIBLY INCREASE THROUGH EARLY TUE AS REGION IS GLANCED

BY SHORTWAVE IMPULSE NOW CROSSING KS. STRONG WIND FIELD WITH

SUBSTANTIAL LOW-LVL DIRECTIONAL SHEAR...AND CONTINUED LOW-LL

MOISTURE INFLOW NNEWD THROUGH THE MS VLY...SUGGEST POTENTIAL FOR A

FEW SUSTAINED STORMS/SUPERCELLS. THESE COULD YIELD MARGINALLY SVR

HAIL...LOCALLY DMGG WIND...AND /MAINLY WITH PRE-FRONTAL

ACTIVITY/...A COUPLE TORNADOES.

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