MAY 2019: Wednesday Storm Complex/Scattered Showers To End May

[Cpv17]

Latest GFS:

[srainhoutx]

Very active weather week ahead with strong to possibly severe thunderstorms possible Monday night into Tuesday and again Thursday into Friday.

Heavy rainfall with potential Flooding issues appears to be a growing threat throughout the Work Week into next Weekend. We will dig into the details later, but if you live in flood prone areas, near our area Rivers or work outdoors, have plans read. We are keeping a very keen eye on next weekend as the various computer models suggest a stalled frontal boundary could be stationary over our SE Texas Region. Below is a 7 Day Rainfall Outlook issued this morning by the Weather Prediction Center. It is possible these amounts may be too conservative particularly in the Thursday through Saturday time frame. Stay Tuned!

[cperk]

Very active weather we ahead with strong to possibly severe thunderstorms possible Monday night into Tuesday and again Thursday into Friday.

Heavy rainfall with potential Flooding issues appears to be a growing threat throughout the Work Week into next Weekend. We will dig into the details later, but if you live in flood prone areas, near our area Rivers or work outdoors, have plans read. We are keeping a very keen eye on next weekend as the various computer models suggest a stalled frontal boundary could be stationary over our SE Texas Region. Below is a 7 Day Rainfall Outlook issued this morning by the Weather Prediction Center. It is possible these amounts may be too conservative particularly in the Thursday through Saturday time frame. Stay Tuned!

That map is scary.

[srainhoutx]

NOAA NWS Storm Prediction Center
Severe thunderstorms are possible over the Mid Atlantic, Southeast, and Plains states today. The pattern is expected to remain active this week across the Plains, and eventually into the Mississippi Valley, with a severe thunderstorm threat expected every day through Thursday (5/9). Refer to our outlooks (https://www.spc.noaa.gov/products/outlook/) and remain weather aware by checking forecasts from SPC and your local NWS forecast office

[Cromagnum]

That map bodes poorly for those near the Brazos.

[srainhoutx]

That map bodes poorly for those near the Brazos.

Jeff Lindner‏Verified account @JeffLindner1 · 58m58 minutes ago
Residents along the Brazos River in Waller, Austin, Fort Bend, and Brazoria Counties need to monitor the river forecast closely this week @fbcoem @wallercountyoem @BrazoriaCounty #houwx #hounews

[srainhoutx]

Midday Sunday weather briefing from Jeff:

After a brief break over the weekend…the threat for both severe weather and heavy rainfall will return for much of the next week.

An upper level trough will develop over the SW US, yet again this week, sending one disturbance after another across TX resulting in clusters and rounds of thunderstorms producing heavy rainfall. Pattern is somewhat similar to spring 2015/2016 which resulted in multiple flooding events across TX in the month of May of both of those years.

Monday night/Tuesday:
A strong disturbance will move across SC TX Monday and into SE TX Monday night and Tuesday with widespread showers and thunderstorms. Heavy rainfall of 1-2 inches with higher isolated totals will be possible along with a slight severe weather threat. Think most of the area will be able to handle this round of rainfall as long as there is no sustained cell training that develops and the overall forward progression of the system remains faster enough to prevent rainfall totals from piling up. What this system will likely accomplish is further saturation of the soil conditions over the area…and a “primer” event for more sustained heavy rainfall toward the end of the week.

Thursday-Saturday:
Another strong storm system will approach toward the end of the week along with a slow moving and stalling surface frontal boundary. The addition of a surface focus in an extremely moist air mass is concerning along with the overall slow eastward progression of the storm system moving out of MX. This is still a bit off, but models are showing significant heavy rainfall signals during this period of several inches as several rounds of slow moving thunderstorms impact the region. Flooding and severe weather will be possible during this period.

Rainfall Totals:
WPC rainfall totals over the next 5 days show widespread averages of 4-5 inches over much of SE TX…and there will almost certainly be higher isolated totals. The widespread nature of the incoming weather this week on top of increasingly saturated grounds, and already swollen rivers, creek, and bayous increases the flooding threat. Main concern will be the Brazos, Trinity, and San Jacinto River basins and toward the end of the week the Harris County bayous and creeks if the current forecast holds.

Confidence is increasing that an active period of weather will affect the area this week with both severe weather and heavy rainfall amounts possible. Exact timing of the rainfall and storms as well as amounts and locations of the higher totals will be in flux over the next 5 days.

Forecasted Rainfall Totals (next 7 days):

[DoctorMu]

Very active weather we ahead with strong to possibly severe thunderstorms possible Monday night into Tuesday and again Thursday into Friday.

Heavy rainfall with potential Flooding issues appears to be a growing threat throughout the Work Week into next Weekend. We will dig into the details later, but if you live in flood prone areas, near our area Rivers or work outdoors, have plans read. We are keeping a very keen eye on next weekend as the various computer models suggest a stalled frontal boundary could be stationary over our SE Texas Region. Below is a 7 Day Rainfall Outlook issued this morning by the Weather Prediction Center. It is possible these amounts may be too conservative particularly in the Thursday through Saturday time frame. Stay Tuned!

That map is scary.

Q. What can't we spread this rain out throughout the summer?

A. Because it is Texas.


I have noticed the amount of deluges has increased over the 28 years we have lived here, and periods between rains in the summer have lengthened.

[DoctorMu]

Midday Sunday weather briefing from Jeff:

After a brief break over the weekend…the threat for both severe weather and heavy rainfall will return for much of the next week.

An upper level trough will develop over the SW US, yet again this week, sending one disturbance after another across TX resulting in clusters and rounds of thunderstorms producing heavy rainfall. Pattern is somewhat similar to spring 2015/2016 which resulted in multiple flooding events across TX in the month of May of both of those years.

Monday night/Tuesday:
A strong disturbance will move across SC TX Monday and into SE TX Monday night and Tuesday with widespread showers and thunderstorms. Heavy rainfall of 1-2 inches with higher isolated totals will be possible along with a slight severe weather threat. Think most of the area will be able to handle this round of rainfall as long as there is no sustained cell training that develops and the overall forward progression of the system remains faster enough to prevent rainfall totals from piling up. What this system will likely accomplish is further saturation of the soil conditions over the area…and a “primer” event for more sustained heavy rainfall toward the end of the week.

Thursday-Saturday:
Another strong storm system will approach toward the end of the week along with a slow moving and stalling surface frontal boundary. The addition of a surface focus in an extremely moist air mass is concerning along with the overall slow eastward progression of the storm system moving out of MX. This is still a bit off, but models are showing significant heavy rainfall signals during this period of several inches as several rounds of slow moving thunderstorms impact the region. Flooding and severe weather will be possible during this period.

Rainfall Totals:
WPC rainfall totals over the next 5 days show widespread averages of 4-5 inches over much of SE TX…and there will almost certainly be higher isolated totals. The widespread nature of the incoming weather this week on top of increasingly saturated grounds, and already swollen rivers, creek, and bayous increases the flooding threat. Main concern will be the Brazos, Trinity, and San Jacinto River basins and toward the end of the week the Harris County bayous and creeks if the current forecast holds.

Confidence is increasing that an active period of weather will affect the area this week with both severe weather and heavy rainfall amounts possible. Exact timing of the rainfall and storms as well as amounts and locations of the higher totals will be in flux over the next 5 days.

Forecasted Rainfall Totals (next 7 days):

The Canadian and GEFS Ensemble are buying is as well. We're going to need a bigger boat.

[DoctorMu]

Picked up 1.75" last night and was up around 2AM to watch the line of thunderstorms pass through my area. It was not too bad considering I was a under a Tornado Warning. Enjoying the sun and partly cloudy skies this afternoon and will again tomorrow. A stormy wet week ahead.

5.6 inches of rain here Thursday - early Saturday am Beautiful, but muddy day yesterday with lower dew point.

[Cpv17]

With all the rain being forecast, tv mets are sure being conservative with rain chances.

[Ptarmigan]

May has flooding rains in the past like in 1907, 1914, 1929, 1981, 1989, 1997, 2015.

Significant Houston Area Floods
http://www.wxresearch.com/almanac/houflood.html

[Cpv17]

5-10” over the next week for southeast TX with isolated spots receiving even more than that according to the WPC.

[Katdaddy]

Day 2 of active weather across S Plains that will continue through the week. 22 tornadoes were reported to the SPC yesterday. The SPC has many of the same areas in a Marginal to Slight area again today. For SE TX, we will take it day by day. Today should be a decent day with increasing clouds as a storm complex moves across SW and S TX. Thunderstorm chances will begin to increase late tonight and this will be the beginning of a long weather week through next weekend. Periods of severe thunderstorms and heavy rain will be possible. By next weekend a stalling front and associated thunderstorms will increase the flood threat. This is a weather aware week and upcoming weekend.

[snowman65]

is it just me, or does it seem like this year's spring storms are bigger and more frequent than past years. is this something we should get used to sseeing now. each year more frequent and intense? seem like Texas gets it worse every year. week after week. you can almost set your watch by it.

[snowman65]

tired of seeing this same picture every week.

[Andrew]

I am pretty concerned about the hail (and tornado) potential over the Panhandle tomorrow. Some of the mesoscale and global models indicate 4-5k of CAPE over the region. Large hail will be a big concern for the reason and later in the afternoon after some weak cyclogenesis occurs, surface winds look to back enough to create a tornado risk. It doesn't take much to get convection surface based with how much energy is expected.

Closer to home, I think tonight there will be scattered storms, but the main days to watch will likely be Wednesday and Thursday. Models indicate the front will stall across SE Texas on Thursday and we have seen in the past what that could mean. Overall, it will be a very active week for many across the state.

[tireman4]

Heavy Rainfall Next Week

[tireman4]

000
FXUS64 KHGX 060834
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
334 AM CDT Mon May 6 2019

.DISCUSSION...

High clouds from the disturbance currently propagating across
central TX has helped to keep temperatures from cooling quite as
much west of I-45 given the blow off of high clouds. That being
said, dew point depressions have narrowed enough to allow for some
patchy fog to develop this morning across SE TX. Anticipate the
patchy fog to burn off shortly after sunrise. High temperatures
today should rise into the low to mid 80s, with the warmest
temperatures east of I-45 where there should be less cloud cover
overhead. Onshore flow has resumed and precipitable water values
(PWs) are expected to rise to just below an inch by this
afternoon, with moisture spreading from west to east considering
1000-500mb relative humidities. The chance for showers and
thunderstorms will be on the rise as we move into the overnight
hours as a shortwave propagates west to east across the region,
embedded in the 500 mb flow, flowed by the main trough axis.

Some uncertainty as we move into Tuesday morning, with a spread of
solutions in both the global and short term guidance. The ECMWF,
NAM12, and ARW continue to trend wetter, bringing the best
coverage of rainfall along and south of I-10. On the contrary, the
GFS keeps the best coverage across our western zones starting as
early as 06Z Tuesday, or late tonight. The TX Tech WRF and NMM
also place the best overage over our far western zones. Taking a
look at current radar imagery, the TX Tech WRF and GFS appear to
have initialized best this morning, given the showers and
thunderstorms currently draped over central and southern TX, and
therefore have trended the forecast closer to their drier
solutions. By Tuesday afternoon into Wednesday, the best chance
for showers and thunderstorms shifts over the northern zones,
mainly north of a line from Colorado to Montgomery to Polk County
into early Wednesday. One thing to note, is the placement of the
best coverage of PoPs does not appear to be in agreement with the
best instability. Taking a look at the lifted index values (LIs),
-9 to -7 hug the coast, with the most unstable values concentrated
over Matagorda Bay. Forecast soundings also show better MU CAPE
values between 1000-1600 J/kg south of I-10. Additionally, upper
level dynamics are not looking favorable, with the 300 mb jet
streak still far west over the TX Panhandle during most of the
precipitation, though there does appear to be better diffluence
by early Wednesday morning across the Red River Valley. The
Weather Prediction Center has placed our western zones in a
slight risk for excessive rainfall through 12Z Tuesday, shifting
this slight risk along and east of I-45 Tuesday through Wednesday
morning. The Storm Prediction Center (SPC) has a marginal risk
for severe storm over our SW zones, counties surrounding
Matagorda Bay, Tuesday through Wednesday morning. At this time,
the moderate to isolated areas of heavy rainfall looks to be the
main hazard Tuesday into Wednesday.

The low level jet at 850 mb really gets pumping early Wednesday
morning, with 35-40 knots over the region. Models look to
resolve a surface low over north TX which digs southwards across E
TX Wednesday into Thursday. The upper level trough associated
with this surface feature remains well to the north of SE TX,
making along I-10 and northward the region under the best chance
for showers and thunderstorm activity Wednesday into Thursday. The severe
threat looks more favorable Wednesday and Thursday, with forecast
soundings showing 0-3 km lapse rates around 7.0 deg C/km, MU CAPE
values of 3000-3500, and a breakable cap with convective
temperatures in the mid 80s. High temperatures should reach or
exceed our convective temperatures, and as the short wave and
trough axis shift eastward, additional lift should help in the
development of thunderstorms. SPC places most of SE TX under a
slight risk for severe storms, with large hail, damaging winds
possible, and isolated tornadoes as the primary weather hazards.
Also to note, grounds should be fairly saturated after this
previous week`s precipitation and the rainfall forecast Tuesday
into early Wednesday, so would not be surprised if localized
flooding becomes a factor once more.

Towards the end of the week, our attention turns to the next cold
front anticipated to stall out across the region. Equivalent
potential temperatures show this boundary best, with the GFS
bringing this front into our northern zones early Friday morning,
while the ECMWF lingers by about 6-12 hours. Global guidance shows
the front stalling just north of I-10 by Friday afternoon, and
acts as a focus for the development of precipitation. This axis
will wash out over SE TX Friday and into the weekend, with
conditions expected to dry out Sunday. Still plenty of uncertainty
in the timing and placement of this boundary, and as a result,
the timing and amount of precipitation anticipated for the end of
the week. As always, we will need to continue to monitor the
trends in global guidance in the coming of days.

Hathaway

&&

.MARINE...
Onshore winds will prevail today with low pressure over SE NM and
high pressure over the TN valley. Not much change through Thursday
as low pressures persist in the lee of the Rockies and high pressure
remains over the eastern US. The pressure gradient tightens Tuesday
night into Wednesday night and a SCEC or perhaps a marginal SCA may
be needed. The gradient will relax on Thursday as a weak cold front
approaches the area. Although there is still some uncertainty,
pressure rises behind the front might be strong enough to nudge the
front into the coastal waters on Friday. Again, a bit of
uncertainty, but at this time a weak to moderate offshore flow may
develop over the weekend and persist into early next week.

Water levels at high tide may approach 3.0 feet today could reach
between 3.0 and 3.4 feet on Tuesday and Wednesday. There could be
some minor coastal flooding at times of high tide mainly Tues/Weds.
43

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 85 68 81 70 83 / 10 40 60 50 70
Houston (IAH) 85 70 81 72 83 / 10 30 60 50 50
Galveston (GLS) 80 74 80 75 81 / 10 30 50 40 30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

Discussion...08
Aviation/Marine...43

[srainhoutx]

NWSWGRFC‏Verified account @NWSWGRFC · 38m38 minutes ago
The situation is sensitive, the flood waves from last week's rainfall is moving toward the coast. Heavy rainfall is expected to return later this week. Soils are saturated, so any heavy rainfall will likely generate new flooding. Be flood aware and flood prepared. #txflood