Hoosier Posted January 23, 2017 Share Posted January 23, 2017 1 hour ago, SouthernNJ said: I heard Dr. Greg Forbes mention something about the winds changing direction during the day, (more W than SW) preventing greater low-level turning. That may have kept some of the circulations above the ground. Also, I am not sure how to read setup parameters, but I do know that LCL-heights cannot be too high for many tornadoes to form. If someone knows what they were in some areas, it might be a category to look at. LCLs were fine. Had manageable T/Td spreads at the surface for the most part. Most of the obs today had S/SW surface winds, so I'm not sure what Dr. Forbes was talking about. Link to comment Share on other sites More sharing options...
Amped Posted January 23, 2017 Share Posted January 23, 2017 30 minutes ago, Hoosier said: LCLs were fine. Had manageable T/Td spreads at the surface for the most part. Most of the obs today had S/SW surface winds, so I'm not sure what Dr. Forbes was talking about. Doesn't look like anyone can answer it off the top of there head. Events like this and the August 24th outbreak show that there are still a lot of unknowns in severe forecasting.. I guess Georgia did get a couple of big ones, but I've seen sea breeze fronts produce more tornadoes over Florida. The 1998 kissimmee outbreak soundings and hodos might be good to look at for comparison. Link to comment Share on other sites More sharing options...
Quincy Posted January 23, 2017 Share Posted January 23, 2017 Substantial low level shear compensated for only "modestly" backed near-surface winds as 0-1km shear was on the order of 40-50kts immediately ahead of the line of storms, supporting >300m2/s2 0-1km SRH. The HRRR did a good job at modeling the simulated radar, even as early as last night, showing "stringy" supercells, due in part to significant shear in the lowest 1-2km. The shear wasn't much higher than recent higher-end events, so I'm not sure it's valid to say there was too much shear. Multiple factors likely played a role. Sure, the CAPE/shear parameter space was great on paper, but even the HRRR didn't seem keen on widespread, intense supercells. More or less, it nailed the idea of only a few significant cells mixed. One argument for high risk is that it's easier to verify in more densely populated areas. That alone could be a defense for the outlook. I wish CIPS would bring their realtime PPF maps back to see what verification looks like. Link to comment Share on other sites More sharing options...
Akeem the African Dream Posted January 23, 2017 Share Posted January 23, 2017 Tornado warning for palm beach county. Link to comment Share on other sites More sharing options...
SouthernNJ Posted January 23, 2017 Share Posted January 23, 2017 TDWR suggests a small, strong circulation moving over streets in an area north of Royal Palm Beach at 1:25 AM EST. Link to comment Share on other sites More sharing options...
SharonA Posted January 23, 2017 Share Posted January 23, 2017 The line still has bits of rotation, but apparently nothing bad enough to trained eyes to justify Warning. The western bits are still over mostly Everglades marsh-and-farmland. The eastern bits are marching towards Coral Springs and Boca Raton as the north-eastern part exits into the Atlantic as a SVR impacting WPB southwards. (edited to fix sloppy wording) Link to comment Share on other sites More sharing options...
SharonA Posted January 23, 2017 Share Posted January 23, 2017 (Edit: The line is now exiting the state & Keys, meanwhile, the next round is about to come onshore from New Port Richey southwards. Doesn't look as bad as earlier today, thankfully). The last TOR of the squall line that the Florida storms became of course had to give Miami watchers heart attacks: Link to comment Share on other sites More sharing options...
NavarreDon Posted January 23, 2017 Share Posted January 23, 2017 MOB prelim's on two EF-2s: Public Information Statement National Weather Service Mobile AL 847 PM CST Sun Jan 22 2017 ...NWS Damage Survey For The 01/21/2017 Perry County Mississippi Tornado Event... .Runnelstown, MS Tornado... Rating: EF-2 Estimated Peak Wind: 125-130 (127 from DAT) mph Path Length /statute/: 7.1 miles Path Width /maximum/: 300 yards Fatalities: 0 Injuries: 1 Start Date: Jan 21 2017 Start Time: 4:05 am CST Start Location: 2 miles WNW of Runnelstown, MS Start Lat/Lon: 31.38006734, -89.14514009 End Date: Jan 21 2017 End Time: 4:13 am CST End Location: 5.5 miles northeast of Runnelstown, MS End Lat/Lon: 31.41937511, -89.03423301 Survey summary: The tornado entered extreme NW Perry County, MS from NE Forrest County 2 miles WNW of Runnelstown, MS and continued to move NE at 45 to 50 MPH before lifting 5.5 miles NE of Runnelstown. Two main areas along the path had significant damage, with EF-2 category winds between 111 to 130 mph. One was located on Pumping Station Road 1.3 miles NW of Runnelstown, and the other 2.7 miles NE of Runnelstown along Cole Drive. Significant tree damage and sporadic power lines were downed along the track of the tornado. The National Weather Service in Mobile would like to thank the Perry County Emergency Management Agency for their assistance today. Public Information Statement National Weather Service Mobile AL 840 PM CST Sun Jan 22 2017 ...NWS Damage Survey For The 01/21/2017 Choctaw County Alabama Tornado Event... .Choctaw County, AL Tornado... Rating: EF-2 Estimated Peak Wind: 115-120 mph Path Length /statute/: 15 miles Path Width /maximum/: 800 yards Fatalities: 0 Injuries: 4 Start Date: 01 21 2017 Start Time: 5:14 am CST Start Location: 2.8 miles southeast of Gilbertown, AL Start Lat/Lon: 31.847599, -88.290451 End Date: 01 21 2017 End Time: 5:31 am CST End Location: 15 miles northeast of Gilbertown, AL End Lat/Lon: 31.99628, -88.10702 Survey summary: The tornado first touched down on Clark Road and continued 15 miles to the northeast to the Choctaw and Marengo County line. A total of 24 structures were damaged by the tornado along its path. Four residences were completely destroyed, including 2 single wide mobile homes and 2 modular homes. Another 20 structures experienced varying degrees of damage. The most significant damage was located on Chapel Hill Road and Pleasant Hill Road. We would like to thank Choctaw County EMA and the people of Choctaw County for their time and assistance with today`s survey. Link to comment Share on other sites More sharing options...
Stormsfury Posted January 23, 2017 Share Posted January 23, 2017 Well SC never got to destabilize due to convective overturning and temps remained in the 60s all day despite great shear parameters during the day. Marine influences also contributed to the lack of SFC based instability. The low pressure system filled too quickly was another possible variant. But the biggest thing was there wasn't enough separation between cells in such a high moisture laden environment. Significant outbreaks usually see much more separate between rotating cells. This case saw way too many cells too close together for many cells to become dominant and muddled/watered things down a bit. Link to comment Share on other sites More sharing options...
Akeem the African Dream Posted January 23, 2017 Share Posted January 23, 2017 6 hours ago, SouthernNJ said: TDWR suggests a small, strong circulation moving over streets in an area north of Royal Palm Beach at 1:25 AM EST. Local media reporting that there may have been a weak tornado touchdown in Jupiter, Palm Beach Gardens , and in my town of Juno. Fair amount of damage to trees,signs, and fences and a lot of unsecured items blown around. Our yard is a mess now. Power was out until 730am Link to comment Share on other sites More sharing options...
NavarreDon Posted January 23, 2017 Share Posted January 23, 2017 3 minutes ago, Akeem the African Dream said: Local media reporting that there may have been a weak tornado touchdown in Jupiter, Palm Beach Gardens , and in my town of Juno. Fair amount of damage to trees,signs, and fences and a lot of unsecured items blown around. Lot's of twitter reports from the Palm Beach Post this am. Link to comment Share on other sites More sharing options...
Akeem the African Dream Posted January 23, 2017 Share Posted January 23, 2017 20 minutes ago, NavarreDon said: Lot's of twitter reports from the Palm Beach Post this am. It appears to have hit the Trump property in Jupiter as part of its path. Link to comment Share on other sites More sharing options...
monsoonman1 Posted January 23, 2017 Share Posted January 23, 2017 Looking at the soundings from yesterday, the meridional flow from 500 mb to 850 mb stands out. Not much curvature in the hodograph above 850 mb. Think the upper low closing off too early may have contributed. Maybe there was too much shear, but with fairly high CAPE I'm not sure. Don't think storm mode was really a problem either; plenty of significant events happen with semi-discrete or cluster modes (think April 28 2014). While I was looking at radar/satellite yesterday, the lack of very strong updrafts/high cloud tops was apparent, other than the Albany, GA area tornadic supercell. Just goes to show that only a slight change from forecast can make a big change in impacts. Quincy pointed out the lack of strong UH signals in HRRR output; I saw that too, but chose to ignore it. Won't happen again. HRRR did very well this weekend on the whole. Will be very interested in storm surveys today and tomorrow. Edit: I should probably mention that SPC was entirely justified with the High risk. Link to comment Share on other sites More sharing options...
monsoonman1 Posted January 23, 2017 Share Posted January 23, 2017 Hattiesburg/Petal tornado appears to be finalized as est. 145mph EF3 with path length 31 miles. Link to comment Share on other sites More sharing options...
Hoosier Posted January 23, 2017 Share Posted January 23, 2017 12 hours ago, Amped said: Doesn't look like anyone can answer it off the top of there head. Events like this and the August 24th outbreak show that there are still a lot of unknowns in severe forecasting.. I guess Georgia did get a couple of big ones, but I've seen sea breeze fronts produce more tornadoes over Florida. The 1998 kissimmee outbreak soundings and hodos might be good to look at for comparison. I guess I'd go with the lack of directional shear above 850 mb. There may have been some other subtle factor that in combination was too much to overcome. Link to comment Share on other sites More sharing options...
Hoosier Posted January 23, 2017 Share Posted January 23, 2017 Just to hit on the lack of directional shear above the lowest km again and what I mentioned last night about some tornado outbreaks having little/no directional shear above 0-1 km, a great example is 11/17/2013 in the Midwest. That event had unidirectional flow aloft and still managed to produce 75 tornadoes, over 30 of which were EF2 or stronger. Here's a sounding from central Illinois that morning, and the special off hour RAOBs taken later in the day farther east show similar wind profiles: Sometimes it's just hard to figure out. Change one thing (or more than one) a little bit and it can throw the whole setup. Link to comment Share on other sites More sharing options...
Amped Posted January 23, 2017 Share Posted January 23, 2017 2 hours ago, Hoosier said: Just to hit on the lack of directional shear above the lowest km again and what I mentioned last night about some tornado outbreaks having little/no directional shear above 0-1 km, a great example is 11/17/2013 in the Midwest. That event had unidirectional flow aloft and still managed to produce 75 tornadoes, over 30 of which were EF2 or stronger. Here's a sounding from central Illinois that morning, and the special off hour RAOBs taken later in the day farther east show similar wind profiles: Sometimes it's just hard to figure out. Change one thing (or more than one) a little bit and it can throw the whole setup. Agreed, no two soundings or hodos are ever identical. Here is some other in for I found from the Carolinas 4-16-11 outbreak that might be applicable. Quote Long-lived squall lines can be expected when the wind shear is perpendicular to the line while squall lines with little or no line-normal shear will likely be shorter-lived and promote more discrete cells. http://www4.ncsu.edu/~nwsfo/storage/cases/20110416/ Link to comment Share on other sites More sharing options...
janetjanet998 Posted January 26, 2017 Share Posted January 26, 2017 . Link to comment Share on other sites More sharing options...
Chinook Posted January 26, 2017 Share Posted January 26, 2017 Yep, I count 114 tornadoes (preliminary- unfiltered) in 4 days. On Wikipedia, it says there have been 62 confirmed tornadoes in the time span of Jan. 21-22-23. I wish there were a more official database than Wikipedia just after the event. In order to count confirmed tornadoes, you have to search around for tornado surveys done by each office, and then start counting. Sometimes that's hard to do. Link to comment Share on other sites More sharing options...
janetjanet998 Posted January 26, 2017 Share Posted January 26, 2017 I see SHV reports on there now and as of this posting northing confirmed out of the central FL SUPS Link to comment Share on other sites More sharing options...
janetjanet998 Posted January 26, 2017 Share Posted January 26, 2017 from the weather channel January 21-23, 2017 Tornado Outbreak One of Largest Winter Outbreaks on Record in U.S. Story Highlights A swarm of tornadoes tore through eight southern states in late January 2017. Only one other January outbreak since 1950 spawned more tornadoes. Hattiesburg, Mississippi, and Albany, Georgia, were particularly hard hit. Five Largest U.S. Tornado Outbreaks in December-February (1950-2017; Source: Dr. Greg Forbes/The Weather Channel; NWS for 2017 estimate) Jan. 21-22, 1999 129 tornadoes Feb. 5-6, 2008 ("Super Tuesday") 86 tornadoes Jan. 21-23, 2017 62 tornadoes (confirmed) Jan. 29-30, 2013 56 tornadoes Jan. 7-8, 2008 49 tornadoes Link to comment Share on other sites More sharing options...
Solak Posted January 28, 2017 Share Posted January 28, 2017 Southeast Regional Climate Center(SERCC) shared U.S. Tornadoes's photo. 2 hrs · Thanks U.S. Tornadoes for the great map. Over 50 alone in our region. U.S. Tornadoes 21 hrs · Now 73 confirmed tornadoes with last weekend's outbreak. One of the largest winter outbreaks on record. http://bit.ly/2hV6m5D (we'll update the tornado list at bottom of the linked page later today) Link to comment Share on other sites More sharing options...
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