ATL: Invest 91L - Discussion

[CyclonicFury]

Despite the stronger 00z models, Avila lowers the chances to 0/10.

000
ABNT20 KNHC 140501
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Thu Jun 14 2018

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

A surface trough over the northwestern Caribbean Sea and the Yucatan
Peninsula is producing disorganized showers and thunderstorms. This
activity is likely to move west-northwestward across the Yucatan
Peninsula and over the southwestern Gulf of Mexico today and Friday.
Environmental conditions are becoming less conducive for the
development of this disturbance.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...10 percent.

$$
Forecaster Avila

[Haris]

central tx wins this run of the euro . expect more jumps

[cycloneye]

A surface trough located over the Yucatan Peninsula is producing
disorganized showers and thunderstorms. This activity is expected to
move west-northwestward across the Yucatan Peninsula and over the
southwestern Gulf of Mexico today through Saturday. Development,
if any, of this disturbance should be slow to occur due to strong
upper-level winds.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...10 percent.

[srainhoutx]

Thursday morning briefing from Jeff:

Locally heavy rainfall possible Sunday-Tuesday

Tropical feature over the western Caribbean Sea will move into the southern Gulf of Mexico on Friday and the western Gulf of Mexico on Saturday. Development of this system appears to be low due to strong wind shear over the Gulf of Mexico, but this wind shear will be weakening this weekend so this system will need to be monitored for any attempts at development over the weekend. The NHC currently places the 5 days development chances at 10%.

Large influx of moisture will begin on Saturday as the wave axis approaches the TX coast and then slowly moves inland Sunday and Monday. Global models have come into slightly better agreement that the main axis of moisture looks to be aimed at the upper TX coast Sunday and Monday. The forecast for Saturday is more uncertain as the moisture may begin to arrive late delaying the best rain chances until the afternoon into the evening hours. Sunday and Monday looks to have widespread showers and thunderstorms.

Rainfall Amounts:
Not much change to the widespread 2-5 inches with isolated higher amounts over a 2-3 day period. Any sort of banding features or training of storms would result in quick rainfall accumulations and much higher totals on a local level. Air mass will become extremely moist with PWS of 2.1-2.6 inches by Sunday and a nearly saturated profile indicating storms will maximize their rainfall efficiency. Short durations storm totals of 2-3 inches will be possible in an hour or less under any organized storms or any areas of S to N training.

While confidence continues to increase on the widespread rainfall amounts, where any particular location may see the higher isolated totals remains unclear.

Hydro:
Grounds are dry over the region and will be able to absorb the first few inches of rainfall without much run-off. Flash flood guidance remains in the 4-6 inch range for 6 hours over the area. Main concern at this point would be any location that receives intense short duration rainfall amounts of 2-3 inches in an hour or less. Even with dry grounds this is a large amount of rainfall in a short period of time and would likely result in street flooding and ponding. Grounds will gradually saturate as the event moves into Monday and Tuesday and more significant amounts of run-off may be generated at that time.

Marine:
As the tropical wave axis moves into the western Gulf of Mexico conditions across the coastal waters will be deteriorating this weekend. Long fetch ESE/SE winds of 20-25kts will begin to build seas starting on Saturday and peaking Sunday/Monday in the 7-10 foot range. Long period swells will begin to arrive along the TX coast late Saturday into Sunday and latest ET surge guidance is indicating water level and wave run-up closer to advisory levels along the Gulf beaches on Sunday. ET surge is showing nearly 1 foot of storm surge on top of the normal tide cycle by early Sunday with total water level of just over 3 feet at Galveston Pleasure Pier.

[wxman57]

Tropical development chances remain slim. Still looks like widespread rainfall totals of 2-5 inches across south and southeast Texas from Sunday to Wednesday. There could be some training storms which could produce up to 10-12 inches of rain in isolated areas. Generally, just beneficial rain most areas (minus the occasional street flooding).

[wxman22]

12z GFS is more aggressive with rainfall across Southeast Texas.



12z Canadian

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Thu Jun 14 2018

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

A surface trough, accompanied by an area of disorganized showers
and thunderstorms, has emerged over the southern Gulf of Mexico and
the Bay of Campeche. This system is expected to move generally
west-northwestward over the southwestern Gulf of Mexico today
through Saturday. Development, if any, of this disturbance should
be slow to occur due to strong upper-level winds.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...10 percent.

Forecaster Stewart

[Nederlander]

KFDM/KBTV Beaumont is projecting a widespread area of 6-10” stretching from Houston to the TX/LA border and north toward Lufkin, with isolated heavier amounts of up 16” through Monday night. I actually just moved back into my house a week ago after it flooded from Harvey. Here’s to hoping we just get much needed rain and no homes flooding (or I might actually go crazy).

[wxman57]

I'm not sure where that KDFM rainfall map is coming from (what model). There is too much uncertainty to indicate widspread rainfall of 8" or more. 12Z Euro has much less rain for Houston and east than 00Z run. GFS isn't very heavy for much of SE TX, though it does have one spot of 6-9" over Galveston Bay. But it's impossible to say this far out where any storms may stream inland.

[MississippiWx]

EPAC activity continues to make development unlikely across the Gulf and Caribbean. 91L was never given a chance due to land interaction and high shear. 10 percent chance seems generous.

[Steve]

EPAC activity continues to make development unlikely across the Gulf and Caribbean. 91L was never given a chance due to land interaction and high shear. 10 percent chance seems generous.

You might be right. I’m not sure. This is one of those invests I don’t have a good feel any way about it. It’s been firing off despite some hostile upper conditions. And it’s always been connected to the deep tropics. EC looks like it might get the early location right, but it generally saw a trough axis with a deep tropical surge. There might be a window Saturday into Sunday for development. It’s hard for me to guess either way, but I wouldn’t be surprised at all if we ended up with a depression or lower end tropical storm. If it doesn’t move into Mexico or S TX but was to stall or parallel the coast, chances probably go up. If I had to guess, maybe 35-40% shot at a depression and maybe 15% shot at a storm?

[CyclonicFury]

EPAC activity continues to make development unlikely across the Gulf and Caribbean. 91L was never given a chance due to land interaction and high shear. 10 percent chance seems generous.

You might be right. I’m not sure. This is one of those invests I don’t have a good feel any way about it. It’s been firing off despite some hostile upper conditions. And it’s always been connected to the deep tropics. EC looks like it might get the early location right, but it generally saw a trough axis with a deep tropical surge. There might be a window Saturday into Sunday for development. It’s hard for me to guess either way, but I wouldn’t be surprised at all if we ended up with a depression or lower end tropical storm. If it doesn’t move into Mexico or S TX but was to stall or parallel the coast, chances probably go up. If I had to guess, maybe 35-40% shot at a depression and maybe 15% shot at a storm?

Shear is expected to drop below 20 kt at about 48 h and steadily decrease afterwards based on the latest SHIPS guidance. Though unlikely, a quick, weak spin-up near east Texas is not out of the question and this is why NHC is maintaining chances at 10% rather than dropping 91L from the TWO.

[cycloneye]

00z Best Track:

Location: 21.6°N 92.9°W
Maximum Winds: 20 kt Gusts: N/A
Minimum Central Pressure: 1011 mb
Environmental Pressure: 1015 mb
Radius of Circulation: 140 NM
Radius of Maximum Wind: 80 NM

[Steve]

Yeah I hear you. And I’ve been watching satellites instead of surface obs and didn’t realize how far west the lowest pressure had gotten to. Damn. Best track has 92.9W at 7 tonight. Time is also a factor.

[latitude_20]

Tulum, Mexico reporting in. Rain stopped about two hours ago. High clouds and a wet beach are going to prevent my turtle nest monitoring for tonight. Best plan is Tequila.

Regards,

Lat20

[Storm Battered]

EPAC activity continues to make development unlikely across the Gulf and Caribbean. 91L was never given a chance due to land interaction and high shear. 10 percent chance seems generous.

You might be right. I’m not sure. This is one of those invests I don’t have a good feel any way about it. It’s been firing off despite some hostile upper conditions. And it’s always been connected to the deep tropics. EC looks like it might get the early location right, but it generally saw a trough axis with a deep tropical surge. There might be a window Saturday into Sunday for development. It’s hard for me to guess either way, but I wouldn’t be surprised at all if we ended up with a depression or lower end tropical storm. If it doesn’t move into Mexico or S TX but was to stall or parallel the coast, chances probably go up. If I had to guess, maybe 35-40% shot at a depression and maybe 15% shot at a storm?

Shear is expected to drop below 20 kt at about 48 h and steadily decrease afterwards based on the latest SHIPS guidance. Though unlikely, a quick, weak spin-up near east Texas is not out of the question and this is why NHC is maintaining chances at 10% rather than dropping 91L from the TWO.

East Texas is considered Tyler, Carthage, Longview, and so on. Well inland.

[Weather150]

[cycloneye]

Bye:

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Fri Jun 15 2018

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Tropical cyclone formation is not expected during the next 5 days.

$$
Forecaster Blake

[TheStormExpert]

Name or no name.

 https://twitter.com/bigjoebastardi/status/1007587654857355264

[Frank P]

Convection off the east coast of the Yucatan looks more impressive right now than anything in the GOM... most convection I’ve seen with this weak system to date... hopefully it will make it to the areas that need the rain!