ATL: IMELDA - Post-Tropical - Discussion

[HurricaneAndre2008]

Maybe a storm in the morning?

[sphelps8681]

Will this start moving northward? If so when will this happen if it does?

[Cpv17]

Will this start moving northward? If so when will this happen if it does?

I hope it keeps drifting west. The more west this goes, the more beneficial rains we’ll get in Texas. Houston and points east of there don’t even really need the rain that much. Unfortunately, it’s looking like that’s exactly what’s going to happen, but I’m still hopeful that it’ll keep drifting west another 100 miles or so before the northern movement occurs.

[lrak]

https://radar.weather.gov/radar.php?rid=CRP&product=N0Z&overlay=11101111&loop=yes looks like some turning out there. And that turning is under the only IR reflection that isn't showing signs of dying out.

[Tailspin]

18z ec Forecasts upto 17inches of rain over a few days in a few areas.
https://imgur.com/g4c1Zif

[lrak]

18z ec Forecasts upto 17inches of rain over a few days in a few areas.
https://imgur.com/g4c1Zif

Sometimes 8hrs makes a change with the GOM concerned.

Ahh...i'm guilty of -removed- after reading my posts

[Jagno]

Early this morning I sent a picture of the "perfect rotation" I saw in the gulf and told my friend that it looked like a perfect mild hurricane with a clear eye in the center and storms surrounding it although our local forecast didn't mention anything but a possibility of a few showers this afternoon. I work in Texas and live in Louisiana so I pay close attention to the weather and what my driving conditions will be. I checked this afternoon and it wasn't nearly as symmetrical as it was earlier so I blew it off. I couldn't believe this evening they are now considering it an invest. Looks like I'll have some interesting travels for the next few days.

[1900hurricane]

Consiering some of the rainfall implications for my area, I should probably pay more attention to this than I have been. One of the earlier ECMWF runs gave me 18.89" of rain, so yeah...

[Tailspin]

yeah the ec 12z had upto 30inches in some areas,so it's a downgrade.https://imgur.com/0jlPOQv

[jasons2k]

Couple of observations --
1) Hardly any deep convection right now
2) Lots of dry air all around

It is tightening-up, but it has a lot of work to do to become classified as anything.

[SoupBone]

Couple of observations --
1) Hardly any deep convection right now
2) Lots of dry air all around

It is tightening-up, but it has a lot of work to do to become classified as anything.

This is what I was saying earlier, you could clearly see the moisture being sapped out of the system.

[underthwx]

Not very impressive on Satellite, I guess we shall see what tomorrow brings?

[Tailspin]

https://imgur.com/QgM9aVB

looks a midget tc on regem.

[aperson]

It has that microcane sort of structure with a small but persistent bit of convection that's just starting to show some banding.



The airmass it's embedded in looks more midlatitude: drier and lower tropopause height. Vorts also look reasonably stacked (but elongated) up to 500mb with no 200mb presence. I wonder if that will temper higher rain rates or if it will moisten the environment back up in time.

[southerngale]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Tue Sep 17 2019


Shower activity associated with a broad area of low pressure over
the northwestern Gulf of Mexico has become a little more
concentrated during the past several hours. Nearby observations
indicate that although pressures are falling in the area, there are
no signs of a surface circulation at this time. Some slight
development is possible before the system moves inland along the
northwestern Gulf coast Tuesday night. Regardless of development,
this system is expected to produce locally heavy rainfall and
possible flash flooding along portions of the central and upper
Texas coastal areas later this week. For additional information,
see products issued by your local weather forecast office and the
Weather Prediction Center.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...low...30 percent.

$$
Forecaster Avila

[SoupBone]

This thing seems to have lost a lot of its moisture envelope this evening and is now a very tight core system. I wonder if it will be able to stage a comeback.

[GCANE]

Radar showing a nice feeder band on the south side of the CoC

[underthwx]

98L looking healthier this morning, up to 30% as of 2am NHC outlook update, we shall see what the day brings, either feast, or famine.

[srainhoutx]

Tuesday morning weather briefing from Jeff:

Heavy rainfall event and flash flood threat this evening through Thursday for SE TX.

Flash Flood Watch will go into effect at 100pm today along and SE of a line from Wharton to Houston to Cleveland

Mid level low pressure system clearly noted in radar data from Houston and Corpus Christi continues to spin over the NW Gulf of Mexico about 150 miles south of Palacios. Numerous rainbands have formed in the last few hours across the NW Gulf of Mexico from Galveston Bay to over 200 miles off the upper TX coast and are rotating inland as far as Downtown Houston this morning. Brief heavy rainfall is likely with these bands this morning. Overall expect an increase in the frequency of these bands today and some potential for cell training in the Flash Flood Watch area which could produce a quick 1-2 inches of rainfall through this afternoon.

Mid level low pressure system and weak surface low/trough will begin to slowly lift northward into SE TX tonight through Wednesday night with numerous showers and thunderstorms expected. Best estimate track for this feature is inland over Matagorda/Brazoria Counties and then slowly NNE into Fort Bend and Harris Counties Wednesday and NNE toward Montgomery and San Jacinto Counties on Thursday. Global guidance has shifted ever so slightly eastward overnight with the track of this feature. Heavy rainfall both near the core or center of the low pressure area and within bands on the eastern and southern flank of the system will be likely. This becomes especially true late tonight into Wednesday as the 850mb moisture transport increases along with good low level inflow off the Gulf of Mexico. Moisture values will be extremely high during the period with PWS ranging from 2.35-2.65 inches which will support intense rainfall rates in any deep and sustained convective developments.

Rainfall Amounts:
Widespread rainfall amounts of 5-7 inches are expected over much of the area with isolated totals of 10-12 inches. Deep tropical moisture in place will support excessive hourly rainfall rates in deeper convection with rates of 1-3 inches possible. While grounds are dry, rainfall today will start to result in gradual saturation of the soil conditions and as rainfall totals increase over the next 24-36 hours run-off will also increase. Flash flooding will be possible under any areas of sustained training or cell clustering. Some of the higher resolution guidance is showing some indications of banding and potential for cell training late tonight into much of Wednesday over the region.

Hydro:
While watersheds are currently running below base flow, expected rainfall amounts will almost certainly lead to significant run-off once grounds become saturated. Rises on creeks and bayous to bankfull or above will be possible leading to more significant flooding. High short duration rainfall rates will lead to street flooding at times. Think most of Harris County can currently handle 5-6 inches of rainfall before significant bayou and creeks flooding would be a concern. However this greatly depends on the intensity of the rainfall rates and any breaks between the intense rainfall cells. Given the complexities in where any sort of training bands may become established yields little confidence on where any higher totals and larger flood threat would be.

WPC has placed portions of SE TX in a moderate risk for flash flooding today, Wednesday, and Thursday.

[wxman22]