Windspeed

That cell near the AL/TN line may be trying...

This was earlier as the couplet was moving through Russellville.

Tight couplet west of Russellville, AL.

That is a nasty hail core on the super cell near Belmont in Tishomingo County, MS.

Today's SPC PWO risk graphic for posterity.

http://www.spc.noaa.gov/products/watch/ww0014.html

  SEL4

   URGENT - IMMEDIATE BROADCAST REQUESTED
   Tornado Watch Number 14
   NWS Storm Prediction Center Norman OK
   340 PM CDT Mon Mar 19 2018

   The NWS Storm Prediction Center has issued a

   * Tornado Watch for portions of 
     Northern Middle Tennessee

   * Effective this Monday afternoon and evening from 340 PM until
     1100 PM CDT.

   * Primary threats include...
     A couple tornadoes possible
     Scattered large hail and isolated very large hail events to 2
       inches in diameter possible
     Isolated damaging wind gusts to 60 mph possible

   SUMMARY...A few severe storms should develop east through the
   evening with a risk for large hail, tornadoes, and damaging winds.

   The tornado watch area is approximately along and 40 statute miles
   north and south of a line from 35 miles south of Clarksville TN to
   70 miles east of Nashville TN. For a complete depiction of the watch
   see the associated watch outline update (WOUS64 KWNS WOU4).

   PRECAUTIONARY/PREPAREDNESS ACTIONS...

   REMEMBER...A Tornado Watch means conditions are favorable for
   tornadoes and severe thunderstorms in and close to the watch
   area. Persons in these areas should be on the lookout for
   threatening weather conditions and listen for later statements
   and possible warnings.

   &&

   OTHER WATCH INFORMATION...CONTINUE...WW 13...

   AVIATION...Tornadoes and a few severe thunderstorms with hail
   surface and aloft to 2 inches. Extreme turbulence and surface wind
   gusts to 50 knots. A few cumulonimbi with maximum tops to 450. Mean
   storm motion vector 25040.

   ...Grams

 

 

 

That sounding is super contaminated by ongoing convection and not representative of the actual atmosphere.

Yikes...

Good morning. I suspect we're in for a long evening and night. Good luck to everyone as far as hail or wind damage. And don't forget to unplug your sensitive electronics and hardware if you're going to be away from your home this afternoon-evening. Sometimes surge & ups fail and warranties can't replace everything.

Cyclone Marcus has been quite nuisance for Darwin and Kimberley in N. Australia the past few days. The core will be pulling away from the coast on Monday and will put on quite a show this week in the SE Indian Ocean. Forecast reasoning and modeling suggests a rapidly intensifying and prolonged cyclone event and Marcus may reach Category 5. Fortunately it will be doing so a good distance away from land.

Had a possible tornado touchdown just south of Tellico Plains in Coker Creek area. 1 structure damaged alot of trees/power poles snapped. Currently 1048 FLEC customers out of power. No injuries.

**Warning: Loud volume with explicit language**

I saw this video on another site that mentioned near Etowah. Save your ears and adjust volume down prior to viewing.

Surprised none of you in here have mentioned the risk for severe weather on Monday...

3 hours ago, jaxjagman said:

This was the same storm that also produced a F5 in the southern counties of Tn.In Lawrenceburg it went through the Amish country,don't know how no one died from that community.
 
https://en.wikipedia.org/wiki/Tornado_outbreak_of_April_15–16,_1998

The Lawrenceburg footage is very intense. Perhaps the most violent tornado ever recorded in Tennessee on video. Though the 20 mile path traversed sparsely populated communities, still quite miraculous that it resulted in no deaths.

21 hours ago, jaxjagman said:

March, 2-3 is the Anniversary outbreak of 2012
 
http://www.spc.noaa.gov/exper/archive/event.php?date=20120302

Day of the EF-4 Henryville, Ind. tornado:

..and that same day near Chattanooga, an EF-3 hit Ooltewah and Cleveland, Tenn., and also this EF-2 in Etowah:

That does not look good.  Any updates on those cells and what happened on the ground?

Some organizing supercells moving towards north-central Alabama. Weak rotation but nothing yet tornadic.

Gita is a gorgeous cyclone. The status is currently at Category 4. Though it temporarily reached Category 5 yesterday, it has maintained a fairly steady large eye and taken on some annular characteristics. A reminder that categories in the S. Pacific and Australia are not the same as the N. Pacific and N. Atlantic.

Did it not snow fairly significantly in the eastern Valley following weekend after the March 12-13th event as well? I believe we were around 14" officially at KTRI for the Blizzard of '93 event, though closer to 18" on average at our house. But later that next week I seem to recall an additional 3-6" off a seperate clipper.

Edit: Nope, I'm getting the '96 blizzard mixed up with the '93 blizzard. Also, looking at the intervals of time between major blizzards during my childhood and teenage years is depressing.

Severe Cylcone Gita is churning away in the S. Pacific near Tonga. It is still classified a Cat 4 based on latest advisory, though, based on over-night imagery, it may have weakened temporarily or gone through an ERC. That process appears to have completed as the eye is again clearing out. The core will cross through a favorable environment and higher SSTs the next 24-48 hours. As such, Gita may not yet have reached its maximum intensity. The core will pass very close if not over the island of Ono-i-Lau very close to or at Cat 5 intensity.

A new peer-reviewed study in the British Royal Meteorological Society journal Weather is proposing that Super Typhoon Haiyan is likely the most intense cyclone ever observed in the Satellite Era. They believe the center eye pressure peaked near 860 mb.
http://onlinelibrary.wiley.com/doi/10.1002/wea.3045/full

Quote

Since 12 October 1979, Typhoon Tip has officially remained the tropical cyclone associated with the lowest atmospheric pressure measured at sea level: 870hPa. The average winds over 1min were estimated at 165kn. On 7 November 2013, Typhoon Haiyanwas the first cyclone to have been estimated at 170kn from satellite imagery. In the absence of aircraft reconnaissance, the minimum pressure has been estimated at 895hPa using the wind–pressure relationship. Using data observed at Guiuan meteorological station in the Philippines, we have estimated the minimum surface pressure in the eye of Haiyan. On the basis of the last pressure measurement of 910hPa at Guiuan, which was located at the outer edge of the eyewall, we estimated the pressure gradient for the 11km of the eyewall. This estimation was made using a comparison with the pressure gradient of the eyewall of two of the most intense tropical cyclones for which the pressures were precisely measured by aerial reconnaissance. During these airborne missions, Hurricane Patricia (23 October 2015), which formed in the eastern North Pacific, had a pressure of 879hPa, and Typhoon Megi (17 October 2010), which formed in the western North Pacific, had a pressure of 890hPa. At the time of the aircraft reconnaissance, the sustained winds of 180kn for Patricia (6h before the maximum wind of 185kn) and 160kn for Megi were comparable to the 170kn of Haiyan. Based on the pressure gradient calculated inside the eyewall of Patricia and Megi, we distinguished three scenarios for Haiyan. Each of them gives a minimum pressure at sea level below the 870hPa of Typhoon Tip, which was the world record holder.

I have always argued that Haiyan remains the most intense cyclone we have witnessed in modern times. Had there been reconnaissance, no other cyclone's intensity data sets would top it. This paper puts that in perspective for me. I had no idea the station reading at Guiuan existed. Recorded 18 miles from center fix and measured to 910 mb, that observation is bloody insane! Even loosely estimating gradient, a center pressure of 866 mb is calculated. The authors settled on 861 mb and rounded to 860 mb based on a few variables. The eyewall had held a steady state in the 30 hrs following the last visible completion of an ERC. The coldest tower tops around the immediate wall were not warming at the recording of that surface pressure. The diameter of the eye had actually decreased slightly. Given Haiyan was positioned against the southern periphery of an amplified subtropical ridge (STR) at the time, imbedded in an above mean surface pressure regime, the pressure gradient most likely was not loose at that obs timestamp. They still did not go with the tightest gradient scenario however.

The following is an excellent write-up by Bob Henson discussing the paper over at underground:

Quote

The authors used three possible scenarios to determine Haiyan’s minimum central pressure based upon the time of the 910 mb measurement from Guiuan when the eye was 28km distant. One scenario employed an average gradient of 3.5 mb/km, another 4.0 mb/km, and another 4.5 mb/km. In the low-gradient scenario, the central pressure of Haiyan was estimated at 866.5 mb; the median scenario resulted in a 861-mb central pressure, and the steep gradient scenario an 855.5-mb central pressure. The authors settled on the 861-mb figure, rounded off to 860 mb.

As for the wind-pressure relationship, Patricia officially holds the record for the strongest winds attributed to a tropical cyclone with 185 knots (213 mph) sustained at its peak strength (central pressure 872 mb). This compares to Typhoon Tip’s 165 kts (190 mph) with 870 mb, and Haiyan’s 170kn (195 mph) with a minimum ‘official’ pressure of 895 mb. From these facts alone, we may surmise that the pressure of Haiyan was almost certainly lower than 895 mb, since we know Haiyan was a large typhoon. Using the Dvorak technique, Haiyan was a perfect 8.0 (on a scale of 1 to 8). That being said, several other tropical cyclones have attained that exalted status aside from Haiyan, Tip, and Patricia.

This may all be semantics and the WMO may or may not take this new research into consideration for crowning Haiyan the most intense on record. But at least from a meteorological standpoint, that surface pressure ob is great evidence to support just why Haiyan's satellite presentation at that timestamp has no equal. Had there been a recon flight around that time, in my mind, the windspeeds would have no doubt been the strongest ever recorded in a tropical cyclone. Obviously, this is still speculation, but I believe it was at least 185 kts or equal to Major Hurricane Patricia. But given the surface pressure obs 18 miles from center fix and given the pressure environment, Haiyan may very well have had higher sustained winds. I realize It is difficult to fathom a 190-200 kts cyclone. But keep in mind, even though Patricia had a tiny core, it was imbedded in a surface trough. The hurricane was moving into a weakness by means of an advancing mid-to-upper trough and southwesterly steering regime. Haiyan's synoptic pattern contrasts significantly as the cyclone was imbedded within a moderate easterly steering flow against a strong mid-level ridge and higher surface pressures.

Obviously, we will never know for certain Haiyan's peak windspeeds with the absence of reconnaissance. After considering all these factors and the new paper, however, I am confident Haiyan is the most intense system even if unofficial. To me it remains the Godzilla of tropical cyclones.

6 hours ago, Drz1111 said:

That looks like a typical JTWC "tropical storm" bearing down on Vietnam.

I like this system to undergo a period rapid intensification over the next 24-36 hrs into landfall. I think this makes landfall stronger than 80kts. Perhaps even reaches Category 3. The core is getting established and the upper environment is clearly favorable. 27-28°C SSTs should support sufficient enough instability given the divergence aloft and jetstreak to the north.

Heavy rains the past few days and issues with the spillway have put the Guajataca Dam under significant threat of failure. Placing this here as it's obviously still an aftermath issue by ol'Maria:

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service San Juan PR
1110 AM AST SAT OCT 28 2017

The National Weather Service in San Juan has issued a

* Flash Flood Warning for... A Dam Failure in...
Isabela Municipality in Puerto Rico...
Quebradillas Municipality in Puerto Rico...

* Until 1100 AM AST Sunday

*At 1120 AM AST, the Guajataca Dam remains in a compromised state. Residences and buildings down stream of this dam remain under a flooding threat should the dam fail. This situation is expected to continue for the next several days. This is a correction to remove San Sebastian.

PRECAUTIONARY/PREPAREDNESS ACTIONS...
Community that have been ordered to evacuate over the past days along the Rio Guajataca and continue to be advised to not return. They are advised to comply with those order and not become complacent lured by a false sense of security. Should a complete failure occur this message would be followed by a Flash Flood Emergency.

What the hell?

The public safety department says it’s the responsibility of funeral homes, crematoriums, and hospitals to notify and send or bring bodies to the forensic institute if they’re possible hurricane-related deaths.

But all 10 funeral homes and crematorium directors BuzzFeed News spoke to said they haven’t received any specific guidance on what they’re supposed to do with the bodies of people who died as a result of the hurricane. Ortiz confirmed to BuzzFeed News that no official guidance was sent to funeral homes and crematoriums, many of which take in bodies that don’t need to go to the hospital first.

Ortiz says the directors of the facilities should know better. “They know that the place that they do all the scientific investigations is at the institute,” she said. “The funeral homes are in constant communication with the institute because they’re the ones that bring the bodies and take them back.”

Still, cremating a body requires written approval from the forensic institute — which has the option to ask for the bodies to be sent to San Juan for examination before they’re burned. But the funeral and crematorium directors who spoke to BuzzFeed News said the institute has given them permission to cremate dozens of bodies of people who died of hurricane-related causes, and were not asked to send them to the institute.

Asked specifically about this, Ortiz reiterated it’s on crematoriums and funeral homes to communicate with the forensic institute if they think a death should be examined for inclusion on the death toll.

“We have heard,” that possible hurricane victims were being cremated without examination, Ortiz said. “We aren’t saying that they’re totally true or totally false. But what we are saying is, if you have a case like that, send us all the information to be able to look at it” before cremation.

 something tells me this is going to be presented in a way that is sensationalized...