September 2019 - Warm End of September

[Cpv17]

I think outside of a few areas seeing an additional 2-4”, this event is pretty much over with. Next week is now looking interesting.

[Andrew]

I don't know about the atmosphere being "overworked". Tropical air masses behave differently. The 'atmosphere' above us is being replenished by the circulation pulling-in the air from the west. That line up towards Hunstville is holding together and I see some cells trying to fill-in again along 290 in NW Harris County. I think the bigger question is around inflow and convergence, especially as we get into the nighttime and the coastal band eventually collapses.

Localized boundaries that created the large issue today are gone and no model shows any additional development. Scattered showers will be possible into tomorrow but nothing like today. I think we will be in pretty good shape for now

[davidiowx]

Some of the aerial footage coming out from abc13 of the traffic and flooding on the freeways is unbelievable. I’m relieved I let employees leave before lunch and they made it home. I can’t imagine sitting in that right now.

[bikerack]

Some of the aerial footage coming out from abc13 of the traffic and flooding on the freeways is unbelievable. I’m relieved I let employees leave before lunch and they made it home. I can’t imagine sitting in that right now.

I didn't go in today but one of the people in charge at work today went around and told people they could leave. It sounds like if they didn't leave right then, they got stuck. I think there are about 20 people still at the office trapped by flood waters.

[srainhoutx]

5:30 PM Update from Jeff:

Rainfall is weakening over the area with additional rainfall tonight of generally less than 1-2 inches



Channels:

Lower White Oak: crested and starting to fall. Should see the channel fall below levels of I-10/I-45 over the next 4 hours

Hunting: overbanks along the upper and lower portions of the channel

Halls: flooding along the entire channel

Greens: overbanks from US 59 to Ship Channel

Cedar: overbanks from headwaters to Hwy 146 (Baytown)

East Fork San Jacinto: major flooding will continue into Friday and fall bank within banks Sunday

West Fork San Jacinto: major flooding will continue into Friday and fall back within banks on Saturday

Buffalo Bayou: overbanks in Downtown up to about San Felipe…will slowly crest and fall this evening

48 hr Storm Totals:

[Cpv17]

Just got home from work and emptied 3.2” out of the gauge on top of the 1” yesterday. 4.6” last week and 4.2” so far this week. Awesome!!

[jasons2k]

I don't know about the atmosphere being "overworked". Tropical air masses behave differently. The 'atmosphere' above us is being replenished by the circulation pulling-in the air from the west. That line up towards Hunstville is holding together and I see some cells trying to fill-in again along 290 in NW Harris County. I think the bigger question is around inflow and convergence, especially as we get into the nighttime and the coastal band eventually collapses.

Localized boundaries that created the large issue today are gone and no model shows any additional development. Scattered showers will be possible into tomorrow but nothing like today. I think we will be in pretty good shape for now

Look at the radar south & east of Galveston. You can see the inflow starting to ride over the top of the decaying band, and new bands are forming SW to NE along the convergence zones. No I'm not predicting a repeat of last night, but I am saying we can't write this off until the remnant low stops sucking-in inflow off the Gulf, and it's not finished yet. You have to remember when you have a tropical low in the vicinity, it changes the rules re: localized boundaries, especially at night.

[jasons2k]

Area Forecast Discussion
National Weather Service Houston/Galveston TX
506 PM CDT Thu Sep 19 2019

...Flood Watch Remains in Effect for Most of SE TX Overnight...

.SHORT TERM [Tonight through Friday Night]...
The overnight MCS/band of storms has persisted and has slowly sag-
ged south this afternoon is still going fairly strong across areas
stretching from Columbus southeast to Jamaica Beach at this time.
Of concern for the next few hrs is the possibility of another em-
bedded shortwave approaching from the west. Scattered storms have
been developing/filling in from this direction this afternoon and
we are still seeing decent inflow/moisture from the Gulf. Keeping
the Flood Watch in place overnight given all these ongoing issues
with high water/saturated grounds as it should not take that much
for conditions to get bad once again. But despite this being said,
will be expecting the activity to decrease a shortly/this evening
with the loss of heating. However...given this very very tropical
air mass over SE TX and the remnants of Imelda still lingering in
and near East TX...this break could be brief. Would not be at all
surprised with spotty SHRAs developing overnight.

Models are continuing to shift the remnants of this system to the
NE tomorrow, and we will be expecting the focus of development to
also shift more NE/E with time. Barring any leftover outflows (or
other boundaries), activity tomorrow afternoon will be more scatt-
ered in nature.

[Andrew]

I don't know about the atmosphere being "overworked". Tropical air masses behave differently. The 'atmosphere' above us is being replenished by the circulation pulling-in the air from the west. That line up towards Hunstville is holding together and I see some cells trying to fill-in again along 290 in NW Harris County. I think the bigger question is around inflow and convergence, especially as we get into the nighttime and the coastal band eventually collapses.

Localized boundaries that created the large issue today are gone and no model shows any additional development. Scattered showers will be possible into tomorrow but nothing like today. I think we will be in pretty good shape for now

Look at the radar south & east of Galveston. You can see the inflow starting to ride over the top of the decaying band, and new bands are forming SW to NE along the convergence zones. No I'm not predicting a repeat of last night, but I am saying we can't write this off until the remnant low stops sucking-in inflow off the Gulf, and it's not finished yet. You have to remember when you have a tropical low in the vicinity, it changes the rules re: localized boundaries, especially at night.

Inflow has been present all day. The thing that made this situation so much worse was the convergence zone over Central SE Texas. At the end of the day, the rules remain the same and any tropical systems still have to follow the dynamics and thermodynamics of the atmosphere. Will scattered rain showers remain present through tomorrow? Yes, but we shouldn't see anything close to what we saw today.

[jasons2k]

Have to say, radar is suddenly going quiet..

[Belmer]

Snippet from the latest HGX discussion:

RAINFALL RECORDS SET FOR TODAY:

CITY OF HOUSTON: A RECORD RAINFALL OF 9.18 INCHES WAS SET AT CITY OF
HOUSTON TODAY. THIS BREAKS THE OLD RECORD OF 6.92 INCHES SET IN
1979. THIS IS NOW THE WETTEST DAY IN SEPTEMBER, BREAKING THE OLD
RECORD OF 7.73 INCHES SET ON SEPTEMBER 13 2008 WITH HURRICANE IKE.

GALVESTON: A RECORD RAINFALL OF 5.70 INCHES WAS SET AT GALVESTON
TODAY. THIS BREAKS THE OLD RECORD OF 5.11 INCHES SET IN 1979.

[bikerack]

HISD closed tomorrow

[Cpv17]

I would like to know more about next weeks rain chances. Anyone care to chime in?

[stormlover]

Hrr develops 6-8 inches in Beaumont area/ Hardin County in morning

[Cpv17]

Hrr develops 6-8 inches in Beaumont area/ Hardin County in morning

Well maybe Jasons was on to something earlier when he said we may not be out of the woods yet. HRR looks to develop some pretty heavy storms tomorrow across other areas of SETX too.

[jasons2k]

San Antonio is getting pounded tonight. They are not as equipped to handle so much rain in such a short period of time. So we've had the Houston, Beaumont, and San Antonio metro areas impacted by Imelda. Remarkable for a low-end TS. It illustrates that you don't need a hurricane or a 'major storm' to cause flooding issues.

I harp on this quite frequently on S2K. The number one cause of death from tropical cyclones is not wind damage or storm surge. It is inland flooding.

[stormlover]

I just don’t see hrr is going to verify..

[jasons2k]

Sorry for the multiple posts, but I was away this evening and I'm just now catching-up.

The remnants of Imelda are definitely on the move. She's now moving up into far NE Texas, and approaching Oklahoma. This is good news is that it did not stall and take the hard left turn towards towards Groesbeck/Mexia like the WPC was forecasting yesterday. I do see that the inflow has shifted from the SW that was apparent earlier today to a more traditional SE, onshore flow. As the center pulls off to the north, the chances of additional banding and convergence zones is going to decrease. I think we've finally turned the corner and the focus will now shift to what's in the cards for next week.

[Ptarmigan]

San Antonio is getting pounded tonight. They are not as equipped to handle so much rain in such a short period of time. So we've had the Houston, Beaumont, and San Antonio metro areas impacted by Imelda. Remarkable for a low-end TS. It illustrates that you don't need a hurricane or a 'major storm' to cause flooding issues.

I harp on this quite frequently on S2K. The number one cause of death from tropical cyclones is not wind damage or storm surge. It is inland flooding.

It has been rather dry in Texas lately.
https://droughtmonitor.unl.edu/CurrentM ... aspx?South

Droughts tend to end in flooding.

[jasons2k]

I just did a quick model check and I don’t see anything major left. I’m feeling much better about things drying out now. Always a chance some storms fire tomorrow but nothing major. A cousin sent this over:

Per The Weather Channel, Imelda is the #5 wettest system to hit the contiguous United States. Harvey is still #1