Severe WX April 12-15th, 2018 Severe Potential

KoD

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Location
Huntsville, AL
I didn't thoroughly analyze the parameters for NC/VA so I didn't put much weight on todays threat potential. In hindsight even looking at just the sim reflectivity there was signs of a lively supercell/tornado threat. GFS showed simulated streaks of high decibal return in this area for days.
 
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11
Location
Denham Springs, LA
And that number is going to go up. The somewhat transparent red triangles on this map were "radar confirmed" tornadoes showing gaps in actual LSR's vs. some other known tornado locations. The slightly larger and less transparent red ones are local storm reports.

 
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112
Location
Riverside, Ohio
Damage from likely small QLCS tornadoes in northern Ohio from this event.
2216 UNK 4 S AKRON SUMMIT OH 4103 8153 2 CARS FLIPPED ... LIGHTING TORN DOWN OFF BUILDING ROOF ... MINOR BUILDING DAMAGE TO BURGER KING AND ACME MARKET ... DAMAGE TO ONE GAS PUMP. (CLE)
2233 UNK 1 SW TWINSBURG SUMMIT OH 4131 8147 DAMAGE REPORTED TO A BUILDING AT SR 82 AND CHAMBERLIN ROAD. (CLE)
/QUOTE]
 
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Saragossa, AL
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That supercell followed the route of the Amtrak Crescent for way longer than seems plausible; I've stopped in some of those affected towns on my journeys (Greensboro, Danville, Lynchburg) I will be on the lookout for tornado damage come July, though it passes through NC/VA after dark. Definitely the storm of the weekend/whole event. It's going to be interesting to see how many separate tracks there were or if this was on the ground for a longer track - a QLCS embedded cell producing a consistent strong track of damage like that is impressively uncommon.
 
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14
Location
Caledonia, MS
Sad. :(. That happened to us at our home on April 27 from the tornado that hit Louisville, MS. We found blinds, lots of tiny shards of wood, photos, bills (which is how we knew it was from Louisville), and prescriptions in our yard. We live about 1.5 hours northeast of Louisville. It was heartbreaking. My profile pic is the sky that was overhead when that happened.
 
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59
Location
North Prattville, Al
I didn't thoroughly analyze the parameters for NC/VA so I didn't put much weight on todays threat potential. In hindsight even looking at just the sim reflectivity there was signs of a lively supercell/tornado threat. GFS showed simulated streaks of high decibal return in this area for days.
Great observations. We don’t tend to associate that region with serious severe weather of any frequency. So, it can be somewhat ignored (unless you live there).
As you pointed out, there was solid evidence for an outbreak of severe weather in that region today.
 
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Saragossa, AL
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You'd think I'd pay more attention to day three after April 16 2011 and others, but it kind of slipped my mind to keep up with it. Very impressive day out there.
 
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112
Location
Riverside, Ohio
Damage from the Elon tornado is the worst I've seen so far this year. Multiple homes reduced to bare foundations. It's not likely to be rated as such (context doesn't look supportive), but I'd say EF4 is on the table.
 

JayF

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URGENT - WEATHER MESSAGE
National Weather Service Birmingham AL
233 PM CDT Mon Apr 16 2018

...Windy Conditions Through This Evening Across East Central Alabama
then Frost Possible across the North and East Portions of Central
Alabama...

.Tight pressure gradients will result in continued windy conditions
across the eastern half of Central Alabama this afternoon through
early evening. With clearing skies and winds going light to near
calm toward late evening along with cold temperatures, patchy
frost will be possible across the north and east portions of
Central Alabama during the late night and early morning hours.

ALZ017>021-024>029-036>038-170300-
/O.NEW.KBMX.FR.Y.0005.180417T0700Z-180417T1400Z/
/O.CON.KBMX.WI.Y.0008.000000T0000Z-180417T0200Z/
Blount-Etowah-Calhoun-Cherokee-Cleburne-Jefferson-Shelby-
St. Clair-Talladega-Clay-Randolph-Coosa-Tallapoosa-Chambers-
Including the cities of Oneonta, Gadsden, Anniston, Centre,
Heflin, Birmingham, Hoover, Columbiana, Pelham, Alabaster,
Pell City, Moody, Talladega, Sylacauga, Ashland, Roanoke,
Rockford, Alexander City, Dadeville, Valley, Lanett,
and Lafayette
233 PM CDT Mon Apr 16 2018

...WIND ADVISORY REMAINS IN EFFECT UNTIL 9 PM CDT THIS EVENING...
...FROST ADVISORY IN EFFECT FROM 2 AM TO 9 AM CDT TUESDAY...

The National Weather Service in Birmingham has issued a Frost
Advisory, which is in effect from 2 AM to 9 AM CDT Tuesday.

* TIMING...of the strongest winds will be through 9 pm. Patchy
frost will be possible from 2 am through 9 am.

* WINDS...will generally be 15 to 25 mph with gusts up to 35 mph
through early evening then go to near calm for overnight.

* TEMPERATURES...will range between 33 and 37 degrees for lows
Tuesday morning.

* Impacts...of the strong winds could cause driving difficulties,
a few downed small trees or a few downed larger tree limbs.
Impacts of the frost could result in damaging or killing crops
and other sensitive vegetation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Wind Advisory means that wind gusts of 35 mph are expected.
Winds this strong can make driving difficult...especially for
high profile vehicles. Use extra caution.

A Frost Advisory means that widespread frost is expected.
Sensitive outdoor plants may be killed if left uncovered.

&&

$$

ALZ011-013>015-170300-
/O.NEW.KBMX.FR.Y.0005.180417T0700Z-180417T1400Z/
Marion-Fayette-Winston-Walker-
Including the cities of Hamilton, Fayette, Double Springs,
and Jasper
233 PM CDT Mon Apr 16 2018

...FROST ADVISORY IN EFFECT FROM 2 AM TO 9 AM CDT TUESDAY...

The National Weather Service in Birmingham has issued a Frost
Advisory, which is in effect from 2 AM to 9 AM CDT Tuesday.

* TEMPERATURES...will range between 33 and 37 degrees for lows
Tuesday morning.

* IMPACTS...of the frost could result in damaging or killing
crops and other sensitive vegetation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Frost Advisory means that widespread frost is expected.
Sensitive outdoor plants may be killed if left uncovered.

&&

$$

ALZ035-041>050-170200-
/O.CON.KBMX.WI.Y.0008.000000T0000Z-180417T0200Z/
Chilton-Autauga-Lowndes-Elmore-Montgomery-Macon-Bullock-Lee-
Russell-Pike-Barbour-
Including the cities of Clanton, Prattville, Fort Deposit,
Hayneville, Wetumpka, Tallassee, Montgomery, Tuskegee,
Union Springs, Auburn, Opelika, Phenix City, Troy, and Eufaula
233 PM CDT Mon Apr 16 2018

...WIND ADVISORY REMAINS IN EFFECT UNTIL 9 PM CDT THIS EVENING...

* TIMING...of the strongest winds will be through 9 pm.

* WINDS...will generally be 15 to 25 mph with gusts up to 35 mph.

* IMPACTS...of the strong winds could cause driving difficulties,
a few downed small trees or a few downed larger tree limbs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Wind Advisory means that wind gusts of 35 mph are expected.
Winds this strong can make driving difficult...especially for
high profile vehicles. Use extra caution.
 
Messages
112
Location
Riverside, Ohio
Elon/Amherst tornado has been rated high-end EF2. I really need to hear some rationale behind that decision, because otherwise I'm baffled. The frequency of which WFOs are assigning EF2 ratings to completely destroyed frame-built homes this year is honestly starting p*ss me off a little. It sets a bad precedent for future surveys too. If the construction is really that horrid, just go with 138 MPH EF3, but applying EF2 to leveled frame homes essentially changes the definition of EF2 damage, and sends us further back into the "La Plata Syndrome" years. That is my concern.
 
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Messages
160
Location
Boaz,AL
Elon/Amherst tornado has been rated high-end EF2. I really need to hear some rationale behind that decision, because otherwise I'm baffled. The frequency of which WFOs are assigning EF2 ratings to completely destroyed frame-built homes this year is honestly starting p*ss me off a little. It sets a bad precedent for future surveys too. If the construction is really that horrid, just go with 138 MPH EF3, but applying EF2 to leveled frame homes essentially changes the definition of EF2 damage, and sends us further back into the "La Plata Syndrome" years. That is my concern.
Text from Wiki:A few homes in this area were leveled, though they were poorly anchored and overall context was not indicative of a tornado stronger than EF2 in intensity.
Here's the drone damage video.
 
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Saragossa, AL
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Well as I basically said a few months ago, EF3 is the new EF5 for impossible standards. According to Wiki, 25 EF2s this year (at least three now pegged at highest possible EF2) and even our lone EF3 was only later upgraded to such from, yes, highest possible EF2. They seem to be defaulting to the lowest possible estimate on the DoD in every single instance. I know construction quality is poor in many areas, but seriously? Aerials seem to suggest nearly slabbed homes, for which the very lowest bound DoD estimate is low EF3.
 
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Messages
164
Location
Madison, WI
Yeah, I don't understand what they think they are gaining by deliberately lowballing as many ratings as possible. I haven't looked too closely at damage on these particular tornadoes so I will withhold judgement on them for now, but the habit of defaulting to the lowest possible estimate on the DoD (as Equus so well put it) , as if slightly overrating by a category was a far worse sin than underrating, has been a longstanding gripe of mine.

My hunch, and it's only a hunch, is that this practice is being advocated by wind engineering types such as Tim Marshall (whom I greatly respect as a veteran chaser and severe weather researcher). I think they might be of the opinion that, by creating the impression through this damage survey "data" that houses are built so poorly that it only takes a "mere" EF2 tornado to level them, they can encourage better construction practices.

Now I'm all for improving construction standards in the name of safety, but in my opinion the intent of damage surveys should be purely meteorological. It should aim to answer the question "How strong was this tornado, to the best of our ability based on the damage it left behind?" Nothing more, nothing less.
 
Messages
112
Location
Riverside, Ohio
Yeah, I don't understand what they think they are gaining by deliberately lowballing as many ratings as possible. I haven't looked too closely at damage on these particular tornadoes so I will withhold judgement on them for now, but the habit of defaulting to the lowest possible estimate on the DoD (as Equus so well put it) , as if slightly overrating by a category was a far worse sin than underrating, has been a longstanding gripe of mine.

My hunch, and it's only a hunch, is that this practice is being advocated by wind engineering types such as Tim Marshall (whom I greatly respect as a veteran chaser and severe weather researcher). I think they might be of the opinion that, by creating the impression through this damage survey "data" that houses are built so poorly that it only takes a "mere" EF2 tornado to level them, they can encourage better construction practices.

Now I'm all for improving construction standards in the name of safety, but in my opinion the intent of damage surveys should be purely meteorological. It should aim to answer the question "How strong was this tornado, to the best of our ability based on the damage it left behind?" Nothing more, nothing less.
Tim Marshall is conservative, but reasonably so. For example, he was lead surveyor for the December 2015 Garland, TX outbreak, and all those ratings were very reasonable, including the 180 MPH EF4. This current situation reeks of either WFOs taking things into their own hands and making their own guidelines, or unsure surveyors lowballing the ratings big time due to lack of confidence in how to apply the scale.
 

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