June 2017: Typical Summertime WX To End Month

[jasons2k]

Deep convection has really died-off during this DMIN, mostly off to the SE now. It will be easier for the center to keep marching WNW/NW, and not get tugged to the east and into the convention (since there isn't much).

Still a lot of dry air to the west, too.

[unome]

http://www.nhc.noaa.gov/marine/forecast ... .php?large

Synopsis for the Gulf of Mexico

GMZ001-200900-
Synopsis for the Gulf of Mexico
458 PM EDT Mon Jun 19 2017

.SYNOPSIS...Potential Tropical Cyclone Three centered near 24.7N 88.7W at 5 PM EDT moving N or 350 deg at 8 kt, with maximum sustained winds 35 kt gusts 45 kt. Highest winds are NE of the center. PTC Three will move north-northwest toward Louisiana and is expected to intensify slightly prior to landfall. Gale force winds and large seas are also expected well east of the cyclone center through Tuesday.

72-hr

[don]

Hmm does this mean they could be shifting the track west with the next update? I guess we will see...

[mcheer23]

add 18z hwrf to the west shift list

[srainhoutx]

Update from Jeff:

Tropical Storm Warning is in effect from Intracoastal City, LA to the mouth of the Pearl River, MS

Tropical Storm Watch is in effect west of Intracoastal City, LA to High Island, TX

The following impacts for SE TX are based on the current 400pm June 19, 2017 National Hurricane Center Advisory.

Note: any changes to the forecast track would void these impacts. Confidence in the current forecast track is below average given the continue spread in the major model guidance.

Winds:
Winds across SE TX will begin to back to the ENE and NE on Tuesday both as a weak front approaches from the NNE and the large circulation of PTC 03 begins to effect much of the Gulf of Mexico. Winds will increase across the coastal waters into the 15-25kt range by early Wednesday and possibly into the 25-35kt range by Wednesday night. Current wind grids from NHC keep tropical storm force winds just east of our area across SW LA and possibly extreme SE TX around Sabine Pass. TS force winds will extend outward upward of 160 miles to the NE of the broad center and only 30 miles to the SW and W. Will go with breezy conditions on Wednesday of 15-20mph across our eastern counties of Polk, Liberty, and Chambers as these counties will be closest to the western portions of the circulation field.

Tides/Seas:
Will bring seas up to 6-8 feet across our 0-20 mile waters on Wednesday with onset of large easterly swells being generated over the eastern Gulf of Mexico. Seas could be upwards of 10-12 feet over our outer waters (20-60nm). Increasing large long period swells will begin to pile more water onto the coast. In addition lunar tides will be increasing toward the middle and end of the week. Current total water levels above mean low lower water (barnacle level) could range from 3-4 feet by late Wednesday. This may get close to resulting in some overwash on Bolivar and the west end of Galveston Island and will likely see much of the Gulf facing beaches covered with water. In Galveston Bay, tides will run 2-3 feet total water level…not expecting any impacts at this time.

Rainfall:
Rainfall gradient will be abrupt with this system due to shear and dry air across the western and northwest Gulf. Moisture plume and feed of deep tropical moisture will be aimed at the state of Louisiana and the central US Gulf coast over the next several days. Rainfall totals of 8-12 inches will be common with much higher totals possible from central Louisiana eastward toward western Florida. Across SE TX rainfall amounts of 1-2 inches will be possible given the current forecast track.

Confidence:
Should the track be shifted westward the above impacts would require significant changes especially the rainfall. Rainfall and flooding will be the primary concern with this system.

Decision Support:

Winds:
TS wind probabilities are around 30% for Chambers and Liberty Counties and 20-30% for areas east of Freeport including Harris County and metro Houston.

Most likely onset of any TS force winds would be around noon Wednesday along Bolivar and Wednesday afternoon across Harris and Galveston Counties.

Tides:
Total water levels of 3-4 feet along Bolivar and Galveston Island on Wednesday
Total water levels of 2-3 feet in Galveston Bay on Wednesday

Seas:
Building 6-8 feet 0-20nm waters Tuesday evening into Wednesday
Building 8-12 feet 20-60nm waters Wednesday

Rainfall:
1-2 inches E of I-45.

06192017 PTC # Track 4 PM CDT DCtluV0UwAAt67r.jpg

06192017 Jeff 1 untitled.png

[jasons2k]

This is my opinion, but I think part of what the models are struggling with is with these sheared systems, we often see center reformations to the north and east, and everything slowly shifts right. But in this case, with this originating as a monsoonal gyre - the circulation is huge. It spans the whole Gulf. So we're not seeing the constant center reformations to the north and east like we often do, just a slow and steady chugging off to the NW.

[brooksgarner]

FYI, so you guys watching KHOU 11 know what we are doing:

Considering this is a significant threat to whoever gets hit by that rain (us included, potentially), we are simply relaying advisories and tracks from the NHC. We will not be speculating on-air about model A or model B, or what-ifs... It's to avoid any possible construing that we're hyping. This is not the storm to explore the "worst possibility." Other than to suggest there "may be a shift" in the official cone, to the west, we are staying away from spaghetti presentations at this time.

I reiterated that the center of circulation is not particularly important to determine who receives the worst of the storm, but that the "dirty side" (east quadrants) are the flood zones. We added that it's not so much a wind threat as it is a rain threat, to whomever endures the impacts of 2"-4"/hour rainfall rates for an extended period.

I do love that we are comparing the models in this forum, as it's a great place to explore trends based on this highly complex setup.

I think we may see a westward shift as well... I told people that while there are "no watches/warnings" for the Houston viewing area and that officially and that we have reduced our rain chance based on the latest NHC track -- this could radically change for the rainier. The NHC says it's going north, but satellite trends may suggest a shift.

Needless to say, it'll be an interesting week. I love the convo's in here!!

-Brooks

[DoctorMu]

This is my opinion, but I think part of what the models are struggling with is with these sheared systems, we often see center reformations to the north and east, and everything slowly shifts right. But in this case, with this originating as a monsoonal gyre - the circulation is huge. It spans the whole Gulf. So we're not seeing the center constant reformations to the north and east like we often do, just a slow and steady chugging off to the NW.

Good point. It looks like this puppy is going to drag dry air underneath and behind it. Angular momentum may win.

[TexasBreeze]

Unrelated to ptc3 some areas sw Houston are getting some heavy storms currently! I can see the clouds blowing up to my sw.

[jasons2k]

It's gonna miss the first forecast point to the west...

[wxman57]

StormGeo's TRAC guidance (Threatened Regions from Active Cyclones) suggests PTC Three is Texas-bound. Almost all 50 of the ECMWF ensembles take it to Texas. The GFS is all-in for Louisiana. The battle is on! It would have to make landfall west of Houston for us to get much rain. And don't expect any significant wind even if it moves right over us. The tropical storm-force winds should remain out over the water.

[Texaspirate11]

Unrelated to ptc3 some areas sw Houston are getting some heavy storms currently! I can see the clouds blowing up to my sw.

Brazoria and Fort Bend County were under severe thunderstorm warnings.

[Cromagnum]

Can someone 'explain why 2 models are greater than 50?

https://mobile.twitter.com/RyanMaue/sta ... 9279689728

[cperk]

Unrelated to ptc3 some areas sw Houston are getting some heavy storms currently! I can see the clouds blowing up to my sw.

Brazoria and Fort Bend County were under severe thunderstorm warnings.

Boy were we i received 1.15 inches in about 20 minutes.

[Katdaddy]

Looking a little more organized this evening with perhaps a feeder band developing NW of the low pressure.

[DoctorMu]

Euro and CMC showing some wrap around rain in TX. Even the GFS...interesting.

[Katdaddy]

A quick break from the tropics......A nice view of outflow/sea breeze storms looking W this evening toward Ft Bend County from NW Galveston County..

[bbadon]

In the last couple frames of the satellite pics it looks like some convection trying to pop near the center. That could certainly aid in development.

[Scott747]

It's still a disorganized mess of a system. Sure doesn't appear to be moving n @ 9 either. Think they will adjust to the w at 10. Might not be enough to issue a watch further down our way.

[Cromagnum]