Windspeed

Positioning of the Azores High and the easterly jet is absolutely in no way conducive for healthy waves and the ITCZ much less tropical cyclone development right now. Anything that could or would consolidate in the MDR is only going to have gaps of very limited developmental time surrounded by hostile atmospheric conditions. As things are going, we're likely going to be waiting until mid-late September, perhaps even early October, for any substantial activity originating from the MDR this season. However, we still may have opportunities for development near the Bahamas, the western Caribbean and Gulf of Mexico with possible interactions of hanging stationary frontal boundaries and weak-to-moderate tropical waves. That would be an issue of timing though. Remember, it only takes one surface low in the right position to make for a memorable event. But at least for now or until a significant pattern shift, I'm not very keen on significant MDR development in 2018 with the current pattern that is in place.

Hector is attaining some characteristics of an annular hurricane. Though it still has a relatively small or modest clear eye, it has lost most of its banding features outside its main ring of convection. Annular TCs can be fairly resilient and long-lasting major hurricanes, even thriving in 26-27°C SSTs and surrounding dry/stable airmasses, as long as the system remains in light/negligible windshear and a region of cooler than average upper tropospheric conditions. Will be interesting to see how long Hector can maintain major hurricane status as it passes by just south of The Big Island of Hawaii.

Today's 12z ECMWF is building a huge dominate central Pacific high and driving Hector all the way into the WPAC now. My previous post may very well end up a non-issue. GFS still breaks down the ridge, but only after Hector misses Hawaii to the SW. Still early though.

In regards to Hurricane Hector and any potential threat to Hawaii, the GFS has trended south over the past few runs and is now more in line with the ECMWF for Hector's 5-7 day track. However, the Euro is considerably slower with track. Though obviously too early for track certainty at this range, there should be a brief weakness in the central Pacific ridge that will allow a more WNW and even NW component of motion before Hector reaches the longitude of Cape Kumukah and before the ridge is shown building back. This could very well end up being a very close call, if not outright landfall, and definitely something to watch for with respect to The Big Island of Hawaii, especially considering the ongoing relief efforts in the lower Puna/Kapoho area and the ongoing eruption in the lower East Rift Zone of Kīlauea Volcano. There are still many displaced residents living in temporary shelters awaiting a more long-term solution beyond just the horrible inconvenience of dealing with a landfalling hurricane. Hopefully the core will miss to the south but I'd feel a little uneasy being that close on the north edge of track guidance in early modeling at that range. As for intensity, though OHC/TCHP and the 26° isotherm isn't that deep around the islands, the near-surface temperatures are warm enough to support a steadily moving hurricane at Category 2 intensity if atmospheric conditions are favorable and shear is low. SSTs are running between 26-27° at the surface and above 27° just south of the Big Island. As is typical with Hawaiian TCs, especially hurricanes, the more southerly the track, the better the potential for a stronger system; furthermore, we don't generally see the stronger hurricane threats outside of El Niño.

We might have to suffer a few days of a real ridge later this week over the weekend. As noted above, we have been on the periphery up to this point. Rain had been able to work underneath the soft underbelly of the ridge up North. In the wake of Chris (even offshore) heights should build from the Midsouth to the Southeast. 
Funny how the same thing is forecast over in China after Maria slams into Fujian Province. It is still pretty far south, like our Gulf Coast. Probably won't qualify as a recurve for downstream North America weather. Hot Tennessee Valley analysis from Jax above looks valid to me. Hopefully it'll ease up around the 20th.

South of Bristol near S. Holston River. Just passed 4" of rainfall since last Saturday. Ground is definitely saturated. Any significant rainfall this afternoon through tomorrow probably results in flooding. Creek flow adjacent to property is at max capacity. Training cells have shifted just barely to my west right now after getting around an inch last hour.

Edit: Here is a good website for extracting rain gauge data around the Tennessee Valley.

It's important to note here that though the official numbers attributed to direct deaths reported by Puerto Rico governmental and civil agencies may have also been incorrect (this is still under investigation), these new estimates by the Harvard Medical peer-reviewed study are attributed to indirect deaths (i.e. deaths due to health-related complications over inaccessible electricity, medicine, basic survival necessities, etc.). An ongoing study and investigation is also being done by George Washington University as well, which was supposed to be out in May, but has been delayed.

It can be debated whether indirect deaths should be attributed to the meteorological-related phenomenon by the hurricane. Personally, I feel like it should be included alongside direct deaths, but kept seperate. Even within a range of acceptable error, these tolls can never be more accurate than estimates due to the logistics of obtaining the data. However, if persons die due to having no access to electricity, medical or basic survival necessities, these are no less signficiant and still due to the impact of the hurricane. Include those estimates in reported numbers, but distinguish direct and indirect, as certainly a combination of factors (i.e. chronic illnesses, poor infrastructure, aid and assistance response time) are also contributing to the deaths beyond meteorological hazards. Again, the loss of life is no less significant and still should be included and attributed to the hurricane due to overwhelming evidence of an increased mortality rate.

It will be interesting to see GWU's results as well.

Edit: Grammatical.

Kind of surprised MRX didn't go ahead and warn this cell over portions of Abingdon, Va. 45-50k tops with nickel-quarter sized hail and intense lightning.

Edit: Looks like they did issue an special advisory earlier at 3:14 EDT for the training cells over that area which was just renewed through 5:15PM for frequent lightning, dime-sized hail and 40mph winds.

The setup for early-to-mid May could be a volatile one for strong storms for the Mississippi and Tennessee Valley. Potent shortwaves enhanced by southwesterly jet out of Mexico, cooler than normal upper levels in May, advancing dry lines out of Texas, strong bulk shear, etc.; it only takes one of those surface lows to come in line to make for a memorable event. Yes, obviously not wanting to overhype so far in advance. Yes, it's Spring and there shall be storms with increasing juicy Gulf moisture as per the norm, but the atmosphere may very well be conducive for at least one strong Southern outbreak.

The NHC has released its Tropical Cyclone Report for Maria:

• Third costliest hurricane in US history.

• Sixth fastest period of rapid intensification recorded in the Atlantic Basin.

• Category 5, 145 kts sustained landfall over Dominica.

• Set minimum pressure record east of 70°W (908 mb) that had only been set a couple weeks prior by Irma (914 mb).

• Category 4, 135 kts sustained landfall over southeast Puerto Rico near Yabucoa. This makes Maria the most intense cyclone landfall in wind speed on US soil since Charley (130 kts) in 2004 and Andrew (145 kts) in 1992, and the strongest for PR proper since the Segundo San Felipe Hurricane of 1928. They mention some of the higher terrain probably did experience category 5 wind.

• 31 deaths in Dominica with 34 missing. 65 deaths in PR, though they mention this number may rise based on an ongoing federal investigation.

Full PDF of report.

Hit 80° here briefly in places around KTRI this afternoon. Quite sunny and felt very Spring-like. Steady SSW surface flow ahead of the front. Could be some pretty good winds overnight as the front passes through and an isolated thunderstorm or two. Branches and general yard debris should make for fun landscaping this weekend.

Summary on the Jacksonville, AL tornado that was rated an EF3. Considering the area it passed through, it's amazing there were no deaths and greater numbers of injured.

Estimated Maximum Wind: 150 mph
Injuries/Fatalities: 4 Injuries
Damage Path Length: 34.29 miles
Maximum Path Width: 2000 yards
Approximate Start Point/Time: 3 SSW Silver Lakes Golf Course
33.8453/-85.9472 at 8:23 pm CDT
Approximate End Point/Time: 4 SSE Mars Hill
33.7943/-85.3665 at 9:10 pm CDT

Oh, hey. My latest YouTube channel ad. A lot of my recent chaseporn crammed into a minute. Enjoy!

Haha nice work, Josh! I headbanged a little. Good luck on your chases this year. May they be as successful as 2017, though hopefully less witnessing to devestation of densely populated areas.

Edit: *2017

Marcus is traversing cooler waters and weakening as expected. Without respite, however, another cyclone is intensifying rapidly out of the Torres Strait and moving into the Gulf of Carpentaria.

Cyclone Nora already has a clearing eye surrounded by -80°C tops and is on the way to becoming severe. The system is moving through an increasingly favorable environment for significant intensification and could interact with land as an intense cyclone. A more unfavorable environment late on the forecast period and slow movement may allow weakening prior to landfall of the cyclone's core. But that same slow movement may exacerbate flooding.

Marcus will definitely be among the most powerful tropical cyclones of 2018:

Quote

             ----- Current Analysis ----- 
     Date :  21 MAR 2018    Time :   193000 UTC
      Lat :   15:36:18 S     Lon :  108:03:12 E

     
             Final T#  Adj T#  Raw T# 
                7.1     7.4     7.4

 Estimated radius of max. wind based on IR : 16 km

 Center Temp : +15.9C    Cloud Region Temp : -80.2C

 Scene Type : EYE  

 Positioning Method : RING/SPIRAL COMBINATION 

 Ocean Basin : INDIAN        
 Dvorak CI > MSLP Conversion Used : CKZ Method  

 Tno/CI Rules : Constraint Limits : NO LIMIT 
                   Weakening Flag : OFF   
           Rapid Dissipation Flag : OFF   

 C/K/Z MSLP Estimate Inputs :
  - Average 34 knot radii :  133km
  - Environmental MSLP    : 1006mb

 Satellite Name :   HIM-8 
 Satellite Viewing Angle : 41.5 degrees 

Severe Cyclone Marcus is a Category 5 on the Australian scale. It would probably be a Cat 5 on the US and Japan scales at some point as well. The cyclone looks to have completed an ERC and the eye that was partially covered in cloud debris appears to be clearing again. Dvorak is closing on AdjT#7 and 135 kts. The CDO is symmetrical with a thick ring of -80°C tops and MW representive of an intense eyewall.

Here's the current Aus Met advisory:
 

Quote

Details of Severe Tropical Cyclone Marcus at 2:00 pm AWST:

Intensity: category 5, sustained winds near the centre of 205 kilometres per hour with wind gusts to 285 kilometres per hour. 
Location: within 30 kilometres of 14.7 degrees South, 111.0 degrees East , 1020 kilometres northwest of Port Hedland and 870 kilometres north northwest of Exmouth . 
Movement: west southwest at 22 kilometres per hour .

Severe Tropical Cyclone Marcus is now tracking in a west southwest direction, well away from the WA mainland. Marcus may strengthen further during Wednesday before tracking towards the southwest on Thursday when it will start to weaken.

That was likely a violent long-tracker unfortunately.

8 minutes ago, Chinook said:

Not sure if we are talking about the same thing, but the area near the HTX radar is now tornado warned (8 mi west of radar). Interestingly, google maps shows terrain with 800 ft vertical differences there.

I was referring to the cell between Cullman / Good Hope i65 and Arley, AL. Though the rotation has weakened now.

Cell ENE of Arley, AL probably about to be tornado warned.

Cullman cell is intense. Looks like they are getting rocked with possible 2-3" hail over downtown.

The strong cell / updraft SE of Addison, AL looks like it may be on the verge of producing. Signs of a couplet forming.

Cell near the state line is bearing down on i-65. Looks more and more impressive. Will pass very near Ardmore.

That's an impressive donut meso on the state line cell...

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