Flash Flood Warning 10, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
426 AM CDT Tue Apr 18 2017

.DISCUSSION...

Flash Flood Watch has been issued for the southern half of SE TX
for this morning through this afternoon.

MCVs over SE TX this morning are producing quite a bit of rain...
with the highest amounts across Brazoria/North Galveston counties
thus far. Radar estimating up to to 9 inches (since midnight) for
locations near Danbury (in Brazoria county). Short-range guidance
keeping this unsettled weather pattern over the CWFA through most
of the rest of the day. Other incoming perturbations (per WV sat-
ellite loops), daytime heating and the proximity of the upper low
itself all lending itself to keeping high POPS across SE TX today.
Jet dynamics aloft also hinting at the continuation of this back-
building pattern of storms.

Despite the weakening upper low over the area, we could see scat-
tered activity on Weds. Lingering boundaries, the seabreeze along
with daytime heating will all be contributing factors. As the up-
per ridge begins to build in from the west, we should see quieter
weather by Thurs/Fri. Looking further ahead, models are remaining
in decent agreement with the cold front on Sat. The upper low de-
epning over the Central Plains will help to drag this boundary a-
cross the state as it moves off to the northeast. Will be looking
for widely scattered/scattered activity with FROPA at this time.
Cooler/drier weather on tap for the rest of the weekend into the
start of next week. 41

&&

.AVIATION...
Messy conditions across the area terminals mainly VFR but patchy IFR
CIGS/VISBY due to proximity of TSRA/+TSRA. Series of slow
moving/meandering upper disturbances should combine with rich Gulf
moisture to keep scattered to numerous showers and thunderstorms
going across the region and at least in the vicinity of the TAF
sites. Areas from ARM-SGR-HOU-GLS probably the most under the gun
through 21z as vorts put the squeeze on the atmosphere. Tonight
should see a diminishing trend in storms with the loss of heating
but vorts remain close by or overhead. So VCSH at a minimum will
probably remain in the area terminals.

45
&&

.MARINE...
South to southeast flow of 10 to 15 knots today should be the norm
outside of the storms today and tonight. The southerly flow
continues through Friday before a Pacific cold front arrives
Saturday. Winds in the wake of the front will likely reach SCEC
conditions and may even reach SCA for 6-12 hours.
45
&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      76  65  82  68  84 /  70  20  20  10  10
Houston (IAH)              77  66  81  68  84 /  70  40  30  10  20
Galveston (GLS)            77  70  78  72  79 /  70  30  20  10  10

&&

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

Hazardous Weather Outlook
National Weather Service Houston/Galveston TX
1002 AM CDT Mon Apr 17 2017

TXZ163-164-176>179-195>200-210>214-226-227-235>238-181515-
Austin-Brazoria-Brazos-Burleson-Chambers-Colorado-Fort Bend-
Galveston-Grimes-Harris-Houston-Jackson-Liberty-Madison-Matagorda-
Montgomery-Polk-San Jacinto-Trinity-Walker-Waller-Washington-
Wharton-
1002 AM CDT Mon Apr 17 2017

This hazardous weather outlook is for portions of Southeast Texas..

.DAY ONE...Today and Tonight

Scattered showers and thunderstorms are possible through this
evening and may be capable of locally heavy rainfall. Stronger
thunderstorms may also be capable of small hail or gusty winds.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Scattered showers and thunderstorms are possible again Tuesday
and may be capable of locally heavy rainfall. Stronger
thunderstorms may also be capable of small hail or gusty winds.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

GMZ330-335-350-355-370-375-181515-
Coastal waters from Freeport to the Matagorda Ship Channel out
20 NM-Coastal waters from High Island to Freeport out 20 NM-
Galveston Bay-Matagorda Bay-
Waters from Freeport to the Matagorda Ship Channel from 20 to
60 NM-Waters from High Island to Freeport from 20 to 60 NM-
1002 AM CDT Mon Apr 17 2017

This hazardous weather outlook is for portions of Southeast Texas..

.DAY ONE...Today and Tonight

A line of thunderstorms moving across the coastal waters today may
result in gusty winds or small hail.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

Special Weather Statement
National Weather Service Houston/Galveston TX
133 AM CDT TUE APR 18 2017

TXZ237-180715-
Brazoria TX-
133 AM CDT TUE APR 18 2017

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL BRAZORIA COUNTY
UNTIL 215 AM CDT...

At 133 AM CDT, Doppler radar was tracking a strong thunderstorm over
Danbury, or near Angleton, moving northeast at 10 mph.

Half inch hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Northern Angleton, Danbury, Liverpool and Chocolate Bayou.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 2918 9545 2942 9533 2929 9512 2924 9509
      2908 9528
TIME...MOT...LOC 0633Z 214DEG 7KT 2919 9532

40