Atlantic - Barry forms July 11, 2019 (tornadoes, snow, rainfall, days)

[Psychoma]

11July2019 11aEDT/10aCDT:

History:
Invest 92L started as an over land thunderstorm cluster / MCS predicted to possibly develop several days in advance. Likely one of the longest lead times for a system that started over land (versus from over water origins). This type of tropical system development doesn’t happen often, but has occasionally over the past few decades. 92L eventually became PTC2 (Potential Tropical Cyclone Two), a way that started officially in 2017 to issue cone maps and Watches/Warnings out before a storm actually formed in order to provide advanced lead times. Almost all PTC’s go on to become actual named storms. On Thursday 11Jul19 aircraft recon measured winds above 40mph making Barry officially a Tropical Storm. Disorganized, but there. Without the PTC system in place, you would just now be getting Watches/Warnings issued.

(Will add more shortly)

[Psychoma]

11Jul19 11aEDT/10aCDT update (continued):

Quick summary: Watches expanded, some Warnings issued, biggest threats: rain/flooding/surge, likely slow development next 24hrs, still poss Cat1 hurricane late Fri night or sometime Saturday, some uncertainty in track/intensity remains.

Stats:
Winds 40mph(65km/h), moving West 5mph(7km/h), pressure 1005mb. Located about 95miles(150km) SSE of mouth of Mississippi River. About 200miles(320km) SE of Morgan City, LA. Tropical Storm force winds (39+mph) extend up to 90miles(150km) mainly just Southeast of storm center.

Barry’s health:
Multiple centers still seen on satellite & by aircraft recon, but looks like one may finally be taking over, so disorganized still. Strongest part of storm by winds is SE of the center currently. Dry air very high up is over the very North Gulf coast East of Louisiana and over ‘center’ of storm, not healthy for Barry. How much this hurts Barry remains unclear. Shear is still over the storm which isn’t helping it organize either. So it’s a mess, we’ll see how it does through the day but it’s not going anywhere fast at the moment. Friday looks better for Barry to start developing though but questions remain on where and what it’ll become.

Warnings (expected to occur within 36hrs or less, rush to finish preparations):
-Storm Surge Warning mouth of Atchafalaya River to Shell Beach Louisiana.
-Tropical Storm Warning mouth of Pearl River (MS/LA border) to Morgan City, LA.

Watches (possible within 48hours or less, prepare in case):
-Storm Surge Watch Shell Beach, LA to MS/AL border.
-Storm Surge Watch mouth of Atchafalaya River to Intracoastal City, LA.
-Hurricane Watch mouth of Mississippi River to Cameron, LA.
-Tropical Storm Watch LA/MS border to MS/AL border.
-Tropical Storm Watch Lake Pontchartrain, Lake Maruepas & New Orleans metro.

Surge possible heights (rise in water above normal tide levels):
-mouth of Atchafalaya River to Shell Beach, LA: 3-6ft
-Shell Beach, LA to MS/AL border: 2-4ft
-Intracoastal City to mouth of Atchafalaya River: 2-4ft
-Lake Pontchartrain: 1-3ft

Additional rainfall:
-Scattered 10-15”, isolated 20”.
-Don’t drive around barricades. Don’t drive into water covered roads. Just a few inches of fast moving water can carry away most vehicles. You don’t know if the road is still there or if structure under it exist anymore. In the US most flood deaths are vehicle related still.

Winds:
Barry expected to intensify, how much still uncertain. Tropical Storm winds (39+mph, but less then 74mph) expected to start reaching portions of the coast Friday morning. 39ish doesn’t sound like much and it’s not by itself but the wear and tear for hours and hours even at just that amount is enough to see scattered downed trees and power lines. Due to flood risk, crews may not go to fix these until the storm has cleared after this weekend.

Tornado:
Small brief lived tornadoes are common in landfalling tropical systems. Most usually form in the NE corner of the storm. These may start by tonight and risk may rise into the weekend.

Safety:
Head all calls for evacuation if told. Prepare for possible downed power lines and trees even well inland. 9-1-1 emergency services may not even try to respond during peak of storm for their own safety. Questions remain for who will see what and what final shape Barry ends up in but time is running out to prepare. Landfall Saturday. Biggest threat is scattered rains and widespread flood potential from the coast and well inland & storm surge. Cell towers typically have battery backup for 24+hrs, use texting if calls cannot get through during storm, sometimes works better. Have multiple ways to receive warnings/info, sometimes systems break in storms. Don’t drive around barricades. In large scale events such as landfalling tropical systems, police do not have the time and resources to block all flooded or tree fallen roads.

As always, official storm stats, cone maps, and any tropical Watches/Warnings come from the US National Hurricane Center every 3 hours (2,5,8&11am/pmEDT, 1,4,7&10am/pmCDT) daily here: https://www.nhc.noaa.gov/

Edit: adding these 2 images:

[Psychoma]

Thurs 11July19 2pEDT/1pCDT - no changes other than pressure ticked up one tiny mb to 1006mb. An unchanging pressure tells us the storm is not currently weakening or strengthening at the moment.

[Cambium]

A look at where Barry is and NHC forecast track. Has it a Cat 1 hitting near Salt Point, LA.


Check out those heat index values. Feels like 100s down there. Dews in the 70s. Talk about tropical. Wow

[Psychoma]

Some of whats steering Barry shown here by Philippe Papin in his thread this afternoon, click on link to see more, no Twitter accnt required:
https://twitter.com/pppapin/status/1149387772303572994

[Psychoma]

11Jul19 5pEDT/4pCDT:

Changes from earlier info with this update:
-Hurricane Warning Intracoastal City, LA to Grand Isle, LA.
-Tropical Storm Warning Lake Pontchartrain, Lake Maurepas & metro New Orleans.
-Tropical Storm Warning Intracoastal City, LA to Cameron, LA.
-Storm Surge Watch expanded to include Lake Pontchartrain
-Lake Pontchartrain potential surge raised to 2-4ft.

Obs:
-Lake Pontchartrain 0.9ft above normal (Weather Channel)
-Mouth of Mississippi River 1ft above normal (Weather Channel)
-Oil rig East of mouth of Mississippi River sustained winds 40mph, gust 52mph (**Note: elevation 525ft, so should be less ground level, NHC report)

Stats:
Winds 40mph, moving West 5mph, pressure 1003mb (down a little from earlier so possible signal it'll try to start strengthening this evening). NHC believes that despite the dry air intrusion into the core/center of Barry and some shear that it will continue to intensify until landfall. Starting to get more convection(storms) near the center now, but still a little ways removed. NHC calls for slow but steady intensification over the next 24hours, may be able to reach hurricane strength Friday evening.

Winds:
Some areas will feel Tropical Storm winds (39+mph) by Friday morning, preparations should be completed before this happens. Hurricane force winds (should storm increase to that by Friday evening) may reach land Friday evening or early Saturday. Landfall 36-48hours from now expected (Sat AM or PM).

[ral31]

Interesting that a lot of the ensemble tracks are west of the operational runs of the GFS and Euro. Local meteorologist thinks NHC may end up nudging its track to the west.

https://ruc.noaa.gov/hfip/tceps/tcep...dtg=2018082812

[Cambium]

I like Bernie's video for snowstorms, I haven't seen this one yet. Assume it good.


https://twitter.com/accuweather/stat...62134859767808

[Psychoma]

Models were shifting more East until a point today, NHC stayed more West side of that guidance, but now models a little more West. NHC mentions in their 5pEDT/4pCDT discussion update that they left their track similar to their previous one but mentions still a large spread in track guidance. We’ll see what happens tonight!

[Cambium]

Warnings are up. Its not the wind with Barry, its the flooding that is the threat.

https://www.pivotalweather.com/