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We drove through Ganado around noon today and water was everywhere. Hwy 59N by Louise had high water in one lane. The rain was incredible. We were driving north on Hwy 172 from Port Alto and the closer to Ganado, the harder the rain. The fields were flooded. The good thing was that everyone was driving with respect and caution.

Only .25" IMBY here in Cypress so far today. I'll take what we can get.

Cpv17 wrote: ↑Sun May 16, 2021 4:33 pm Louise, TX area has already seen close to a foot of rain today. I just missed it today by about 15-20 miles.

See that's what makes me really concerned about this week, if we are already seeing those kind of totals with a much weaker disturbance and less lift than what we will see later this week.That makes me think global models may be under doing the rainfall potential, and we'll have to rely daily on the short range mesoscale models to determine which areas have the potential for excessive rainfall.

don wrote: ↑Sun May 16, 2021 5:35 pm

Cpv17 wrote: ↑Sun May 16, 2021 4:33 pm Louise, TX area has already seen close to a foot of rain today. I just missed it today by about 15-20 miles.

See that's what makes me really concerned about this week, if we are already seeing those kind of totals with a much weaker disturbance and less lift than what we will see later this week.That makes me think global models may be under doing the rainfall potential, and we'll have to rely daily on the short range mesoscale models to determine which areas have the potential for excessive rainfall.

I’ve heard reports coming out of that area just south and sw of El Campo of as much as 14” from this morning. I picked up 1.50” today. Nice steady rain for most of the day.

Im becoming increasingly more concerned that the global models are underdoing the potential rainfall accumulations for tuesday night-thursday,

Solid, steady rain in Friendswood all day today.

I’m getting a bit worried about the next two days as well.

Yeah none of the models were predicting 14 inches of rain today in EE Texas but yet it happened. Im thinking its in the realm of possibility that someone somewhere in SE Texas Tuesday-Thursday could see a bullseye of 15-20 inches. Just depends on where the heavy rain sets up and trains. Looking ar a solid 48-60 hour window of very rain

Only an inch of rain at my place based on rain gauge, but standing water everywhere. Nice rainbow action to cap off the day. Even got a double rainbow.

Jeff on FB tonight.

13.5 inches of rain today near Ganado TX in Jackson County

This airmass and pattern setup mean business, flood threat increases this week.

Be prepared

Impressive lightning storm off to the southeast of Galveston.

NWS qpf map

Virtually nothing in CLL yet, but QPFs are sky high for Monday through Wednesday

Flooding likely.

East side of Houston over towards the Golden Triangle better look out tonight/this morning. We have some training setting up. HRRR model is pumping out some big totals.

Wow! Just woke up. Everything is flooded in Beaumont. I cant leave my house for work. Just looked at the gauge at it’s showing over 4” so far overnight. Heavy heavy rain. Getting concerned about this week because 4-5” is what we were supposed to total all week. Not overnight. Feast/Famine I tell ya. Stay safe everyone!

I have a bad feeling about this . . .

It is not often at all that you see a MODERATE risk issued especially as early as day 3... We also need to watch out late morning and this afternoon as the HRRR is producing localized training with localized spots in metro Houston getting excessive rainfall today.

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
438 AM EDT Mon May 17 2021

Day 3
Valid 12Z Wed May 19 2021 - 12Z Thu May 20 2021

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FROM SOUTH TEXAS
TO WESTERN ARKANSAS AND LOUISIANA...

The upper/mid-level trough will transition from a neutral to
slightly negatively-tilted orientation during this period. This in
turn will help slow the movement/progression of the convection, as
well as, become more favorable for back-building across eastern
and southern Texas. Models suggest very strong vertical motion
will set up over much of coastal Texas and areas inland-- this is
also where the PW values of 1.5 inches is double the seasonal
average for this time of year. Southeast winds of 25 to 35 kts
will continuously direct Gulf moisture onshore which will future
fuel and maintain convection development. Most of the guidance
depict another 2 to 6 inches falling over saturated areas, many of
the same areas that will have received several inches during the
prior two days. The 72-hour footprint across this region has areal
averages of 3 to 9 inches with isolated higher amounts certainly
possible. A Moderate Risk was issued for much of eastern/coastal
Texas and far southwest Louisiana. Several urban areas fall within
this risk area and will likely experience numerous areas of
impactful flooding. A Slight Risk cover most of the eastern half
of Texas, southeast Oklahoma, western Arkansas and Louisiana. The
Marginal covers west-central Texas, most of Oklahoma, southeast
Kansas, western Missouri, east-central Arkansas ans central
Louisiana. If model consensus and confidence continue to trend
upward, and/or observations reveal higher amounts than forecast,
there may be the need to entertain a narrow high risk area in
future updates (possibly over WFOs San Antonio and Dallas/Fort
Worth's area) given that the 72-hour amounts approach 8-9+ inches.

Campbell

So far only .75" since yesterday in NW Galveston County but the atmosphere is loaded and ready.

At 5” now overnight in Beaumont. Just last week I was begging for rain and we were in a drought for my area. Not anymore. Lol. But seriously growing concerned if we still show 7-10” on top of what we already had which is what our local is now forecasting. My work is remained closed because of flooding. No one can get there. Unfortunately its one road in and oNe road out. And it always floods.

Area Forecast Discussion
National Weather Service Houston/Galveston TX
427 AM CDT Mon May 17 2021

.DISCUSSION...

We are now firmly into what will be a week-long pattern of
considerably more disturbed weather, complete with multiple rounds
of showers and thunderstorms, some of them with heavy rain
involved, and only brief respites between aforementioned rounds of
rain.

There are a lot of words below that really dig into specifics of
what we`re expecting, why we expect them, and beyond that, what we
can and cannot confidently predict on this early Monday morning.
Please enjoy them for the technical breakdown they are. If you`re
in a hurry, the TL;DR is this: We find ourselves in a very
conducive environment for showers and thunderstorms each day
across Southeast Texas. The Tuesday night through Thursday morning
stretch likely carries the highest threat for flooding rains, but
that threat is not entirely absent any day this week. Please make
it a point to be aware of the weather situation this week and keep
up with the latest forecast information.


.SHORT TERM [Through Tuesday]...

Today will be the second day of the multi-day wet weather pattern
across SE Texas. Another upper level shortwave will round the base
of an upper low located over the Four Corners today and better upper
level diffluence sets up over Southeast TX. Though low level
moisture content will be somewhat less today (roughly around 0.20-
0.30 inches less), the air mass in place continues to be quite
unstable, in particular, during the afternoon to early evening
hours. The 06Z NAM forecast sounding, for example, show MUCAPE
values between the 3000-4000 J/kg around 21-00Z with 0 CIN. It also
contains 700-500MB lapse rates in the 7 C/km range. A pocket of much
drier air lies between the 800-600MB levels with a moisture increase
just above it. It seems that the areas north of I-10 will be the
most vulnerable for todays` weather. Strong gusty winds and hail may
accompany the stronger storms. The potential for minor flooding due
to slow moving storms producing heavy to torrential rainfall is also
possible, though knowing an exact location for it is still hard to
tell. A Flash Flood Watch may be needed, however, models continue to
have difficulty with initiation, timing, and intensity and have thus
decided to wait and see how the weather develops today before
pulling the trigger on the Flash Flood Watch. The potential is
definitely there however, so it is best to stay watchful and ready.

Tuesday will be the third consecutive stormy day given that
Southeast TX will still have the unstable airmass in place while
having a stronger influence with the trough deepening southward as
the upper closed low finally begins to shift and a more favorable
wind pattern for storms develops aloft. There is also a bigger
consensus on strong storm development along a dry line situated
along the TX panhandle and Western TX. Storms amplifying over
Central TX look to propagate into our northern counties sometime in
the afternoon/evening where locally the environment could very well
support their livelihood. Thus, Southeast TX may end up having a
combination of both locally developed storms and storms rolling in
from the NW. Again, the higher PoPs lie along areas north of I-10.
Therefore, if we are able to obtain enough rainfall today to issue a
Flash Flood Watch for our northern counties, then it will be likely
that the Watch will be continued well into Tuesday or Wednesday due
to this second wave of activity across these sectors. WPC has a
Slight Risk for Excessive Rainfall for northern and western portions
of the CWA for Tuesday with a Marginal Risk extending elsewhere. SPC
also has a Slight Risk for Severe Thunderstorms for the northern
portions of the CWA. It will definitely be an interesting couple of
days for us here in SE Texas.


.LONG TERM [Tuesday Night Through Monday]...

From a deterministic standpoint, I`m not sure there`s much that
can be said about this midweek period that I haven`t already
written about in the past few nights. There remains strong model
consensus for an environment conducive to heavy rains across
Southeast Texas deep into this week. Weather will still be driven
by a closed upper low that will definitely overstay its welcome,
if it hasn`t already. Per NAEFS, precipitable water still looks
to rise to around or above the 90th percentile, while an inflow
jet from the Gulf will also start to be nudging up towards the
90th percentile as well. The Euro ensemble is even more
aggressive, with precipitable water exceeding the 99th percentile
and the inflow jet easily exceeding the 90th percentile; perhaps
even beginning the push the 98th percentile.

It seems pretty safe to say that somebody, somewhere in the
eastern half of Texas is going to get slammed with a lot of rain.
The deterministics have actually been trending downward in their
QPF, though trending down from a cumulative 20 inches closer to
"just" a foot doesn`t seem terribly helpful. Location also varies
significantly among the models. The GFS, Canadian, and possibly
the NAM, now that it`s coming into range, tend to favor the
heaviest axis of rain well inland, perhaps even northwest of our
area entirely. The Euro, on the other hand, swings a lobe of
midlevel vorticity further south, and really tries to focus the
action on a coastal trough.

I`m not even sure, given all the mesoscale factors that will
influence rainfall placement and amounts, that these trends are
even real or particularly helpful to the forecast. When it comes
to the big picture, best to focus on the environment and a broad
sketch of the potential than the specifics right now. Yesterday,
even short range CAM guidance struggled mightily with exactly
where and how much rain would fall. What they did show? Potential
for heavy rain somewhere, and where we got heavy rain was around
Matagorda Bay.

There are probably some things we can see as relatively mutually
exclusive. Typically in these setups, convection offshore or near
the coast can rob moisture from areas further inland, cutting off
areas further north from the rich moisture inflow jet. So if
guidance tends to start favoring a coastal trough more, we may
focus our strongest wording there. On the flip side, if
significant coastal convection doesn`t materialize, that would
increase the danger for heavy rains further inland as that rich
Gulf moisture surges north.

We`ll be searching for signs for a specific scenario such as the
couple I`ve laid out here to try to give as much lead time as
possible on where the highest risk is. It is the primary reason
why a flash flood watch is not being issued on this shift, in
hopes that the highest threat area will become apparent to the day
shift (regardless, expect a watch fairly soon - we are running out
of time). But sometimes, mesoscale features are just so
important, and so difficult to forecast at range, that we`ll be
refining the forecast right into an event. In other words, to
quote the s c i e n t i s t who must predict the future,
"Sometimes science is so difficult it makes me sad".

Beyond the midweek, there are also not much large-scale change in
the forecast into the upcoming weekend. Even though the main
upper low gets drawn up towards the Great Lakes, remnant vorticity
continues to linger over the area. This should allow the broad
environment to back down from the amped up levels leading to the
heavy midweek rain, but should still support more rounds of
showers and thunderstorms late this week and into the weekend.
Eventually - I promise! - the strong eastern US ridge will build
far enough west to return us to a drier, more typical late spring
setup. This is still not entirely dry...but at least should be
more in the vein of a handful of showers and storms through the
course of a day while most stay dry, rather than widespread
wettings for large swaths of the area.

At 6” now in Beaumont...