June 2019: Showers/Storms Increasing To End June

[Andrew]

Well, that de-escelated quickly...

Think they keep the flood watch for tomorrow?

-Steve

The flood watch is still needed because we don't know for sure where the heaviest rain will fall. Just because it is looking more likely it will occur south and east of Houston doesn't mean it can't happen. I don't think much has changed since this morning overall and most locations should see between that 1-4 inch range. Where training occurs is where the flooding will happen.

[DoctorMu]

Nice, steady, slowly soaking in rain up on CLL. For a change, just what we were looking for.

Long way to go, but the Canadian model is most line with precipitation so far.

The weekend is going to suck heat (index) wise, but at least the grass and trees will be watered well.

https://www.wunderground.com/forecast/u ... alwx_10day

[jasons2k]

Gotta watch the progress of that little circulation by Brownsville to see if it does any convective warm core rains overnight in its pathway. It is already helping pull up moisture on the offshore waters this morning.

The remnants of the eddy northwest of Brownsville looked like it would get going for a few hours, but it’s winding down now.

[srainhoutx]

Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 420 AM EDT Wed Jun 05 2019 Day 1 Valid 12Z Wed Jun 05 2019 - 12Z Thu Jun 06 2019 ...

THERE IS A HIGH RISK OF EXCESSIVE RAINFALL ACROSS THE MIDDLE TO UPPER COAST OF TEXAS INTO SOUTHWEST LOUISIANA...

...Eastern Texas into Southwest Louisiana... There is a strong model consensus for very heavy to excessive rainfall amounts day 1 along the Central to Upper Texas coast into Southwest Louisiana. PW values 2.25 to 2.50+...3+ standard deviations above the mean...expected to impact much of eastern TX into the Lower MS Valley day 1 in an axis of strong southerly low level flow...850-700 mb moisture flux anomalies 3 to 5 standard deviations above the mean...off the western Gulf of Mexico.

Rainfall intensities likely to increase early this period along the mid to upper TX coast in the above mentioned axis of anomalous 850-700 mb moisture flux off the western Gulf that will be moving only slowly up the TX coast into southwest LA day 1. SREF probabilities for 5"+ rainfall amounts are in the 70-100% range across much of the coastal sections of WFO HGX and LCH CWA...inland by approximately 50 nm. In this region...the latest hi res model consensus is for 6-10"+ amounts with these amounts depicted in WPCs day 1 qpf. Changes to the previous Excessive Rainfall Outlook for this period was to introduce a high risk in the consensus very heavy qpf axis. Otherwise...only some minor changes made to the slight and moderate risk areas...suppressing them slightly southward to match the consensus heaviest precip axis. Widespread major to life threatening flooding possible in the high risk area...especially across the Houston metro region which is susceptible to major flooding issues.

[srainhoutx]

Mesoscale Precipitation Discussion 0368 NWS Weather Prediction Center College Park MD 452 AM EDT Wed Jun 05 2019
Areas affected
...Coastal Texas Concerning...Heavy rainfall...Flash flooding likely
Valid 050848Z - 051445Z

Summary...Flash flooding will gradually become more likely through the day across Coastal Texas as heavy rain bands and thunderstorms become more numerous this morning. Hourly rainfall rates will continue to increase, and may reach 2-4 inches with the strongest thunderstorms. Localized amounts in excess of 5 inches are likely by 10 AM, and the heavy rain may last beyond that time.

Discussion...Convection was increasing within a broad plume of deep tropical moisture across coastal Texas this morning. GPS observations along the entire Texas coast are indicating at least 2.2 inch PWs, and as high as 2.4 inches in some spots. The 00Z CRP sounding and model forecast soundings show tall, skinny CAPE profiles with a deep saturated layer from the surface up through 4km AGL and a deep warm cloud layer. This is all suggestive of highly efficient rainfall processes. MRMS reflectivity profiles continue to show low echo centroids (likely indicating warm rain & collision-coalescence processes) and very limited vertically integrated ice, despite the cold cloud top appearance on IR satellite. This could lead to some underestimates by radar rain rates.

A mesonet site near Midfield, TX showed a rain rate as high as 2 in/hr, but KHGX dual pol only showed 1.2 inches. The 00Z HREF shows neighborhood probabilities of 2+ in/hr rain rates exceeding 40 percent from Matagorda to southern Harris County by 14-15Z, and individual hi-res models have shown rain rates as high as 4 in/hr in some localized swaths. An environment like this with deep tropical moisture and efficient rain bands could conceivably produce rain rates that high, and that would be very likely to lead to flash flooding, particularly if it occurred over urban areas. Regional radars at 0830Z showed a primary convective rain band (with some embedded lightning) stretching from ELA, to BYY, to about 120 miles SSE of BYY. This band has been gradually shifting up the coast, with a lateral motion along the coastline of about 10-15 mph. Extrapolation of the last several hours of radar trends would place this band in the Houston metro area very close to rush hour, with attendant concerns about very heavy rain rates during a time of high road traffic. Beyond the primary rain band as it exists at 0830Z, additional convective rain bands appear likely to develop east of a surface low near CRP, and then gradually merge into an axis of strong surface convergence along the coast. Hi-res models indicate this sort of behavior in their simulated reflectivity products, and there are already some rain bands forming along the Texas coast near CRP. This would have the potential to produce some training rain bands and repeated rounds of heavy rain. The strongest hi-res model signal for heavy rainfall through 15Z is in the aforementioned area from Matagorda County through Harris and Galveston Counties. Flash flooding will become increasingly likely in these areas over the next several hours, with the flash flood threat expanding through the rest of the day. As an additional note, a High Risk has been posted on the Day 1 Excessive Rainfall Outlook for portions of these areas. Please refer to that product and discussion for additional information.
Lamers
ATTN...WFO...CRP...EWX...HGX...LCH...

[Cromagnum]

Pretty good rain south of Houston last night. Pretty mean swath coming in from the southwest just in time for morning commute too.

[Katdaddy]

Remain weather aware across the Houston-Galveston areas through tomorrow. The heavy tropical rains are ongoing across SE TX especially SW of Houston this morning. As Rain posted the Weather Prediction Center has a rare High Risk area for Flash Flooding from the Houston-Galveston areas eastward into SW LA. High rainfall rates are likely with the tropical moisture in place with some models showing 6-10” rain totals. The first Flash Flood Warning has just been issued for counties to the SW of Houston where 4-5” have already occurred.

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Houston/Galveston TX
644 AM CDT Wed Jun 5 2019

The National Weather Service in League City has issued a

* Flash Flood Warning for...
Wharton County in southeastern Texas...
Southeastern Austin County in southeastern Texas...
East central Jackson County in south central Texas...
Southwestern Fort Bend County in southeastern Texas...
Western Brazoria County in southeastern Texas...
Northwestern Matagorda County in southeastern Texas...

* Until 945 AM CDT.

* At 640 AM CDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Flash flooding is expected to
begin shortly. 4 to 5 inches of rain has fallen and another 1 to 2
inches of rain will be possible by 800 AM. The Wharton County
Sheriffs office reported high water at FM 1162 at County Road 422,
FM 1301 at County Road 157 and FM 1161 at County Road 131.

* Some locations that will experience flooding include...
Rosenberg, Richmond, El Campo, Wharton, Needville, East Bernard,
Wallis, Pleak, Simonton, Fairchilds, Beasley, Kendleton, Orchard,
Thompsons, Pierce, Boling-Iago, Blessing, Markham, Cumings and
southeastern Weston Lakes.

[DoctorMu]

The radar looks pretty “excessive” now! It’s really coming down.

Long tongue of rain just west of 59, similar to GFS.

[tireman4]

Radar Image 06 05 19

[tireman4]

000
FXUS64 KHGX 051123
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
623 AM CDT Wed Jun 5 2019

.AVIATION...
A messy day for aviation interests. A surge of tropical moisture
coupled with a weak upper level disturbance, a developing coastal
trough and favorable jet dynamics will bring periods of showers
and thunderstorms to the area for much of the day. A mix of
MVFR/IFR ceilings and visibilities are expected as each wave of
precip moves across SE TX. Strong winds are expected at coastal
TAF sites and added a gust group for KGLS. A mix of MVFR/VFR
ceilings tonight that will probably transition to MVFR across all
TAF sites between 09-12z. 43

&&

.PREV DISCUSSION... /ISSUED 459 AM CDT Wed Jun 5 2019/

SHORT TERM [Today through Thursday Afternoon]...

The first band of storms has made it onshore into Matagorda county
and is producing 1-1/5 inches of rain per hour. The band is inching
it`s way N-NE and if it holds together, should make it into Houston
by 600 AM. A weak trough of low pressure extends along the coast to
a very weak area of low pressure near Brownsville. PW values are
near 2.50 inches and coupled with convergence along the coast and a
splitting 300 mb jet will set the stage for a very wet morning and
early afternoon. Short term guidance is bullish with rain amounts
today with six HRRR runs in a row generating 10 inches of rain in
Galveston County by evening. The HiRes ARW and NMM show similar
results with generally 5-10 inches of rain across Brazoria, SE
Harris, Galveston and Chambers counties. Have made some
modifications to the Flash Flood Watch. Will end the FFA at 03z
since most of the heavy rain should have ended by then and trimmed
the areal extent and removed counties north of a Brenham to Trinity
line. High temperatures today should trend cooler with the clouds
and precip but there could be some late afternoon sun so did not go
too cool.

Models diverge a bit overnight with a couple of solutions bringing a
disturbance into the region. We are still on the east side of an
upper level trough with winds aloft out of the SW so it`s possible
additional showers will develop in the wake of today`s system. Will
maintain chance PoPs overnight.

On Thursday, SE TX will stay lie to the east of the upper trough
axis. PW values are progged to decrease to around 1.70 inches and
fcst soundings show a drier profile. That said, there will still be
some lift on the east side of the trough, favorable jet dynamics and
convective temps are around 90 which looks reachable. In addition,
there is strong frontogenetic forcing at 21z over Central Texas and
this forcing works its way eastward into SE TX around 00z. If
storms develop, some will be strong to severe with large hail and
damaging winds. Will maintain chance PoPs on Thursday.
Temperatures will warm a bit as 850 temps warm and a few more
breaks of sun should boost heating. SPC has much of SE TX under
Slight Risk of severe thunderstorms from 12Z Thursday through 12Z
Friday. 43

LONG TERM [Thursday evening through Wednesday]...

Upper level low is expected to amplify as it moves across AZ/NM
today and into northern TX Thursday. The combination of the upper
level low over North TX, strong winds aloft, and prevailing
surface moisture will induce additional showers and thunderstorms
across the forecast region through Thursday night. Some of these
storms could be severe in nature that are capable of producing
periods of torrential rainfall, strong winds, hail and frequent to
intense lightning. The SPC Convective Outlook has Southeast TX
under a Slight Risk of severe thunderstorms through 12Z Friday.

Additional development of showers and thunderstorms can be
expected Friday. The upper level low shifts eastward while a
pocket of moisture looks to move into the region. GFS PW values
range between 1.5-2.0 inches Friday morning and afternoon.
Favorable CAPE values, 850MB temperature/moisture advection, and
local diurnal effects will also aid in the development of showers
and thunderstorms Friday. SPC Convective Outlook has Southeast TX
under a Marginal Risk of severe thunderstorms from 12Z Friday
through 12Z Saturday. Improving weather conditions are expected
Friday night. A gradual decrease in low level moisture and PW
values can also be seen in the models during this time period.

High temperatures on Saturday and Sunday will generally be in the
mid 90s with isolated locations reaching the upper 90s. Heat index
over the region is expected to range between 105-110 degrees F.
Mostly tranquil weather conditions are expected during the
weekend. Please take extra precaution and safety measure while
outdoors and continue to monitor the latest forecast.

Models continue to suggest a cold front moving across Southeast
TX sometime between Sunday night and Monday morning. Wind data
does show winds shifting to the north during this time. Warm air
advection will also be in place before the arrival of the frontal
boundary with high temperatures in the mid to upper 90s. Rain
chances are forecast to increase by around late Sunday
afternoon/evening through Monday morning as the frontal boundary
moves across the local area. However, keep in mind that this is
well into the end of the forecast period and environmental
conditions could change the forecast during the next several days.

MARINE...

The pressure gradient has begun to tighten as a weak coastal trough
develops. Although winds have been slow to increase, swells
propagating into the coastal waters has increased seas. A Small
Craft Advisory is in effect through the afternoon for the Gulf
waters. In addition, tide levels are also running one to one and a
half foot above normal with tide levels expected to reach 3.6-3.8
feet at high tide. This could cause some minor flooding/wave run up
on Gulf facing beaches at high tide. A Coastal Flood Advisory is in
effect through Thursday afternoon along Gulf facing beaches. Strong
rip currents will be possible through Thursday. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 85 73 91 74 91 / 90 40 40 50 30
Houston (IAH) 83 74 91 76 92 / 90 70 40 40 40
Galveston (GLS) 82 79 89 81 90 / 100 80 60 30 40

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flash Flood Watch through this evening for the following zones:
Austin...Brazoria Islands...Chambers...Coastal Brazoria...
Coastal Galveston...Coastal Harris...Coastal Jackson...
Coastal Matagorda...Colorado...Fort Bend...Galveston Island
and Bolivar Peninsula...Inland Brazoria...Inland
Galveston...Inland Harris...Inland Jackson...Inland
Matagorda...Matagorda Islands...Montgomery...Northern
Liberty...Polk...San Jacinto...Southern Liberty...Waller...
Wharton.

Coastal Flood Advisory until 1 PM CDT Thursday for the following
zones: Brazoria Islands...Galveston Island and Bolivar
Peninsula...Matagorda Islands.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION through this evening for the
following zones: Galveston Bay...Matagorda Bay.

Small Craft Advisory until 10 PM CDT this evening for the
following zones: Coastal waters from Freeport to Matagorda
Ship Channel TX out 20 NM...Coastal waters from High Island
to Freeport TX out 20 NM...Waters from Freeport to
Matagorda Ship Channel TX from 20 to 60 NM...Waters from
High Island to Freeport TX from 20 to 60 NM.

&&

$$

Discussion...24
Aviation/Marine...43

[srainhoutx]

Very heavy rainfall from near El Campo to Wharton to Richmond/Rosenberg slowly heading East. Portions of Eastern and NE Harris County are near 4 inches already with that band to the SW heading in.

[srainhoutx]

Nearing 4 inches just East of Bryan in the Brazos Valley

[srainhoutx]

Update from Jeff:

Moderate to at times heavy rainfall this morning over much of Harris County.

Rainfall amounts have averaged .50 to 1.0 inches over much of the county with totals of 2.0-3.5 inches along Carpenters Bayou to Lake Houston…where a flood advisory is currently in effect.

Large batch/cluster of heavy rainfall with rainfall rates of 1-3 inches per hour is slowly approaching from Fort Bend County and will potentially move into SW/S Harris County (generally S of I-10) over the next 1-2 hours. With grounds now becoming saturated, much of this rainfall will run-off into area creeks and bayous resulting in more significant rises (especially those watersheds S and E of US 59).

Street flooding conditions will likely worsen as this heavy rainfall moves into more urban areas.

[srainhoutx]

High water becoming a problem on the road ways now. Probably a good day to put off travel...if possible.

[srainhoutx]

Nearing 6 inches in Bryan/College Station Area. Those amounts we not expected. Flash Flood Watch was dropped for NW area Counties early this morning.

[srainhoutx]

Public reports 10.47 inches in Wharton

[ajurcat]

SIL in El Campo sent photos of flooded roads there.

[srainhoutx]

Reports of roadways in the Bryan/College Station area becoming impassable due to rising creeks/ditches

[tireman4]

Flash Flood Warning

[DoctorMu]

Nearing 4 inches just East of Bryan in the Brazos Valley

5.9 inches of rain IMBY so far. Major flooding on Hwy 6 feeder roads.

Never can titrate these damn tropical systems. Feast or famine.