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Re: April 2021

Posted: Thu Apr 29, 2021 2:34 pm
by DoctorMu
There's a pearl thread of moisture trying to sneak into the Brazos Valley along a weak front.

https://www.star.nesdis.noaa.gov/GOES/s ... &length=24

Re: April 2021

Posted: Thu Apr 29, 2021 2:37 pm
by DoctorMu
Area Forecast Discussion
National Weather Service Houston/Galveston TX
1223 PM CDT Thu Apr 29 2021

.AVIATION...
A weak cold front is still well to the north of SE TX and it is
very slowly moving southward. The front will reach KCLL between
23-00z and there should be a broken line of shra/tsra. Additional
showers will develop south of the front and feed into t
he line.
Timing things is going to be a work in progress and leaned toward
a HRRR/TT WRF blend. Fcst soundings show some weak capping in the
850-700 mb layer both today and again on Friday yet some of the
CAMs show potential for very heavy rain.
:lol:

Jet dynamics show a splitting jet structure tomorrow so have leaned toward some of the
more aggressive models.
MVFR ceilings are expected this afternoon
with a mix of MVFR and IFR tonight into Friday. Could get some
patchy sea fog near KGLS as well. 43

Re: April 2021

Posted: Thu Apr 29, 2021 2:45 pm
by Cpv17
DoctorMu wrote: Thu Apr 29, 2021 2:26 pm
Cpv17 wrote: Thu Apr 29, 2021 1:17 pm I think the WPC will upgrade the excessive rainfall forecast to either slight or moderate for a good part of southeast TX in their next update. Based on the latest run of models I’m seeing potential for 4+” for a large part of the area. Pw’s will be around 2” and at times could be exceeding that. We will be getting a large batch of unstable moist air from the western Caribbean/Gulf of Mexico.
Maybe so. It's looks pretty dry to me at the moment, with just a hair of a swirl over the western Caribbean

https://www.star.nesdis.noaa.gov/GOES/s ... &length=24

https://www.star.nesdis.noaa.gov/GOES/c ... &length=24

The low over SE New Mexico is more likely the potential wellspring of showers tonight and tomorrow.
Yeah that low will be tapping into a lot of moisture coming from the Gulf. The WPC mentioned that in their last excessive rainfall discussion.

Re: April 2021

Posted: Thu Apr 29, 2021 2:56 pm
by don
Cpv17 wrote: Thu Apr 29, 2021 1:17 pm I think the WPC will upgrade the excessive rainfall forecast to either slight or moderate for a good part of southeast TX in their next update. Based on the latest run of models I’m seeing potential for 4+” for a large part of the area. Pw’s will be around 2” and at times could be exceeding that. We will be getting a large batch of unstable moist air from the western Caribbean/Gulf of Mexico.
I agree, i would be surprised if they didn't upgrade to at least a slight risk with this afternoons update.I'm a little afraid some people could get caught off guard tomorrow if the higher qpf amounts verify. WPC showing widespread amounts of 3-4 inches now.

Re: April 2021

Posted: Thu Apr 29, 2021 3:30 pm
by jasons2k
I welcome the rain but after this system I will be OK with a break. Any rainy days at this point delays my pool construction!

Re: April 2021

Posted: Thu Apr 29, 2021 4:06 pm
by jasons2k
Couple of boundaries working to the NE....

Re: April 2021

Posted: Thu Apr 29, 2021 4:21 pm
by DoctorMu
jasons2k wrote: Thu Apr 29, 2021 4:06 pm Couple of boundaries working to the NE....
Mostly verga at the moment here.

Re: April 2021

Posted: Thu Apr 29, 2021 4:23 pm
by DoctorMu
Midlevel cap may be eroding and moving west.

https://www.star.nesdis.noaa.gov/GOES/s ... &length=24

Re: April 2021

Posted: Thu Apr 29, 2021 4:50 pm
by Cpv17
The WPC upgraded our region to the slight risk in their latest update:

Image

Re: April 2021

Posted: Thu Apr 29, 2021 9:00 pm
by Andrew
Latest HRRR shows some concern for localized flooding Friday morning. Something to keep an eye on for sure.

Re: April 2021

Posted: Thu Apr 29, 2021 9:51 pm
by jasons2k
You can see the outline of many of the major highways on the radar scope. That's interesting...

Re: April 2021

Posted: Thu Apr 29, 2021 9:54 pm
by jasons2k
Flood Watch
National Weather Service Houston/Galveston TX
936 PM CDT Thu Apr 29 2021

TXZ163-164-176>179-195>200-301045-
/O.CON.KHGX.FF.A.0001.210430T0300Z-210502T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Houston-Trinity-Madison-Walker-San Jacinto-Polk-Burleson-Brazos-Washington-Grimes-Montgomery-Northern Liberty-
Including the cities of Shepherd, Cleveland, Groveton, Dayton,
Bryan, Huntsville, Corrigan, Crockett, Liberty, Navasota, Caldwell,
Livingston, Conroe, Brenham, Coldspring, College Station, The
Woodlands, Somerville, Trinity, and Madisonville
936 PM CDT Thu Apr 29 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH SUNDAY MORNING...

The Flash Flood Watch continues for

* A portion of southeast Texas, including the following areas, Brazos, Burleson, Grimes, Houston, Madison, Montgomery, Northern Liberty, Polk, San Jacinto, Trinity, Walker and Washington.

* Through Sunday morning

* Showers and thunderstorms are expected to develop overnight as a cold front slowly sags southward. A widespread 1 to 3 inches of rain is expected, but training of heavier storms may produce localized areas of 4 to 8 inches of rainfall.

* Flooding of low-lying, poorly draining areas and other vulnerable locations are possible if they are impacted by storms with heavier rainfall rates and amounts. Multiple rounds of these storms would worsen the potential for flooding. Where rain rates are more manageable, previously dry conditions will help reduce concerns for flooding.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Watch means that conditions may develop that lead to Flash Flooding. Flash Flooding is a very dangerous situation. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.

Re: April 2021

Posted: Thu Apr 29, 2021 10:11 pm
by Cpv17
Some of the mesoscale models are going nuts showing potential for 10+” in isolated spots.

Re: April 2021

Posted: Thu Apr 29, 2021 10:28 pm
by jasons2k
From Jeff:

Flash Flood Watch has been issued for much of SE TX tonight-Sunday morning.

Afternoon and evening short range model runs continue to suggest a line of slow moving thunderstorms with the potential to produce hourly rainfall amounts of 1-3 inches will develop later this evening into Friday morning roughly from Huntsville toward Columbus and then slowly sag southward toward NW and N Harris County in the 500-700am time frame and then toward I-10 in the 700-900am period. Timing could change either direction by a few hours.

Slow storm motions along with increasing potential for cell training and hourly rainfall rates of 1-3 inches per hour are increasing the threat for street flooding. Widespread rainfall amounts of 2-4 inches is looking increasingly likely with isolated totals of 4-8 inches and would not rule out a 10 inch maximum somewhere. Amounts in the short range (CAMs guidance) have been increasing this afternoon and evening.

Bayous and creeks will be able to handle rainfall amounts upwards of 5 inches, but totals over that in a short period of time could result in near bankfull conditions on some of the smaller channels.

WPC has upgraded much of the area into a slight risk of flash flooding.

Re: April 2021

Posted: Thu Apr 29, 2021 10:41 pm
by jasons2k
Ch 2 Frank B - showed & focused on short-range models showing up to 10" in spots through tomorrow and up to 20" in isolated spots over the weekend.

Ch 11 David P - showed and focused on the Euro model, mostly around 1" with up to 2" in spots through tomorrow, and up to 3-4" in isolated spots through Sunday.

Re: April 2021

Posted: Thu Apr 29, 2021 10:48 pm
by Cpv17
jasons2k wrote: Thu Apr 29, 2021 10:41 pm Ch 2 Frank B - showed & focused on short-range models showing up to 10" in spots through tomorrow and up to 20" in isolated spots over the weekend.

Ch 11 David P - showed and focused on the Euro model, mostly around 1" with up to 2" in spots through tomorrow, and up to 3-4" in isolated spots through Sunday.
That’s not a big difference at all lol

Re: April 2021

Posted: Thu Apr 29, 2021 11:03 pm
by davidiowx
jasons2k wrote: Thu Apr 29, 2021 10:41 pm Ch 2 Frank B - showed & focused on short-range models showing up to 10" in spots through tomorrow and up to 20" in isolated spots over the weekend.

Ch 11 David P - showed and focused on the Euro model, mostly around 1" with up to 2" in spots through tomorrow, and up to 3-4" in isolated spots through Sunday.
Well one of them will be right.. or both in a localized way.

Re: April 2021

Posted: Fri Apr 30, 2021 12:00 am
by Cromagnum
20 inches....hah...sure...

Re: April 2021

Posted: Fri Apr 30, 2021 1:15 am
by Cpv17
Cromagnum wrote: Fri Apr 30, 2021 12:00 am 20 inches....hah...sure...
Well the 0z NAM gets kinda close but it’s probably overdone:

Image

Re: April 2021

Posted: Fri Apr 30, 2021 3:34 am
by Cromagnum
Early morning booming and bumping on the south side. Cells are expanding but so far the meanest part is to my west.

Image