Flash Flood Warning 87, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
656 AM CDT Mon Aug 28 2017

...THE AREA'S FLASH FLOODING AND BAYOU FLOODING WILL BE
TRANSITIONING TO RIVER FLOODING OVER THE NEXT SEVERAL DAYS...

.AVIATION...
TAF sites will be dealing with Tropical Storm Harvey's rainbands and
associated SHRA/TSRA for the next several days. Look for periods of
RA with embedded SHRA/TSRA along with mainly NE to E gusty winds.
42

&&

.PREV DISCUSSION... /ISSUED 542 AM CDT Mon Aug 28 2017/

DISCUSSION...
Overnight, the heaviest rains moved eastward from the previously
heavily devastated Houston-Galveston locations eastward into the
Liberty-Chambers County areas. At 4 AM, Tropical Storm Harvey was
centered near Port Oconnor. A slow southeastward motion is
expected today, and a slow northeastward motion is expected to
begin on Tuesday. These slow speeds will keep Southeast Texas
under a threat for some locally heavy rainfall through Wednesday
with three day (7 AM this morning through 7 AM Wednesday morning)
rainfall totals of 15 to 20 inches possible. The confidence level
on these amounts materializing is on the low end, but
accumulations anywhere close to these values across locations that
have already received heavy rainfall (basically in and around the
area's current Flash Flood Emergency) would have devastating
consequences on the continuing rescue and recovery efforts. The
tornado threat could linger around for a couple more days, but the
greater risk areas have shifted off to our east and will probably
remain in that area. Look for increasing gusty winds and some
elevated tides to develop when Harvey moves up the coast.

MARINE...
Tropical Storm Harvey circulation drifting into and across Matagorda
Bay this morning then out over the nearshore waters south of
Matagorda by mid afternoon. TPC currently forecasting very slow
strengthening over the nearshore waters. Winds picking up throughout
the day and winds should come up from 15-25kts this morning to 25 to
35 knots by late morning with higher gusts possible. Seas building
from 7-9ft early this morning with the flow increase and by this
evening 10 to 16 foot seas should prevail. Showers and thunderstorms
should increase in coverage this afternoon and will likely have a
waterspout threat again this afternoon and overnight.

Some uncertainty on the track of Harvey but generally curving back
to the north tonight and moving back toward the coast somewhere
between Freeport and Sabine pass Wednesday morning or early
Wednesday afternoon. Tropical storm warning remains in effect for
along the Upper TX coast to High Island and that may need to be
expanded eastward.  Elevated tides through Wednesday then gradually
diminishing. After it moves inland and offshore flow crosses
Galveston bay expect tide levels to fall which will strengthen the
outgoing currents and relieve the back pressure on the river
flows. 45

CLIMATE...
Rainfall was extreme yesterday and the city of Houston (Bush IAH)
established a new daily rainfall record with 16.07 inches. It is
the single highest daily rainfall total in city history. In the
last two days, 24.44 inches of rain has fallen. August 2017 is
now the wettest August on record and also the wettest month all
time besting June 2001 (Tropical Storm Allison).

Since June 1st, Houston has received 46.16 inches of rain which is
about 33 inches above normal. The annual average rainfall for
Houston is 49.77 inches, so roughly a years worth of rain has fallen
in the last three months.

College Station recorded 7.45 inches of rain yesterday which is now
the wettest day ever recorded in the month of August and it is the
4th wettest day all time. 43

HYDROLOGY...
Harris County bayous remain high but some of the smaller basins have
begun to recede. Larger streams and rivers continue to rise and many
of these are projected to reach record high crests. Cypress Creek
continues to rise and may breach a levee near Inverness Forest. The
Addicks and Barker Reservoirs are forecast to reach new record high
values and releases from the reservoirs have begun. This will add to
the flow of Buffalo Bayou. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      76  70  80  72  80 /  80  80  70  60  60
Houston (IAH)              76  73  79  74  79 / 100 100  90  80  70
Galveston (GLS)            83  76  83  77  83 /  90  90  90  80  60

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Tropical Storm Warning for the following zones: Brazoria...
     Chambers...Galveston...Harris...Jackson...Liberty...
     Matagorda.

     Flash Flood Watch through Wednesday evening for the following
     zones: 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.

GM...Tropical Storm Warning for the following zones: 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.

&&

08/11/25/33/42/43/45

Hazardous Weather Outlook
National Weather Service Houston/Galveston TX
522 AM CDT Mon Aug 28 2017

GMZ330-335-350-355-370-375-TXZ163-164-176>179-195>200-210>214-226-
227-235>238-291100-
Austin-Brazoria-Brazos-Burleson-Chambers-
Coastal waters from Freeport to the Matagorda Ship Channel out
20 NM-Coastal waters from High Island to Freeport out 20 NM-
Colorado-Fort Bend-Galveston-Galveston Bay-Grimes-Harris-Houston-
Jackson-Liberty-Madison-Matagorda-Matagorda Bay-Montgomery-Polk-
San Jacinto-Trinity-Walker-Waller-Washington-
Waters from Freeport to the Matagorda Ship Channel from 20 to
60 NM-Waters from High Island to Freeport from 20 to 60 NM-
Wharton-
522 AM CDT Mon Aug 28 2017

This hazardous weather outlook is for portions of Southeast Texas.

.DAY ONE...Today and Tonight

Periods of mainly light to moderate rain with embedded showers and
thunderstorms containing heavier rains can be expected across the
area today and tonight as Tropical Storm Harvey moves off the coast
near Matagorda Bay. Any heavy rain falling on locations that have
already received record breaking rainfall will be devastating.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Harvey is expected to work its way up the Texas coast on Tuesday
and Wednesday. This track should bring periods of mainly light to
moderate rain with embedded showers and thunderstorms containing
heavier rains for the area. Any heavy rain falling on locations
that have already received record breaking rainfall will be
devastating.

.SPOTTER INFORMATION STATEMENT...
Spotters will be possible through Wednesday.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
603 AM CDT MON AUG 28 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0721 PM     FLASH FLOOD      2 SSE SHEPHERD          30.47N  94.99W
08/27/2017                   SAN JACINTO        TX   EMERGENCY MNGR

            FLASH FLOODING ON MARIE ST IN SHEPHERD AS WELL AS
            NUMEROUS OTHER PLACES ACROSS THE COUNTY VIA TXDOT LUFKIN

&&

EVENT NUMBER HGX1700407

11

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
606 AM CDT MON AUG 28 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0732 PM     FLASH FLOOD      FRIENDSWOOD             29.51N  95.20W
08/27/2017                   GALVESTON          TX   PUBLIC

            VIDEO OF WIDESPREAD FLASH FLOODING ACROSS FRIENDSWOOD
            VIA TWITTER

&&

EVENT NUMBER HGX1700408

11

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
608 AM CDT MON AUG 28 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0504 PM     FLASH FLOOD      SPRING                  30.06N  95.38W
08/27/2017                   HARRIS             TX   PUBLIC

            PHOTOS OF CARS SUBMERGED IN FLOOD WATERS IN SPRING

&&

EVENT NUMBER HGX1700409

11

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
610 AM CDT MON AUG 28 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0413 PM     FLASH FLOOD      TOMBALL                 30.10N  95.62W
08/27/2017                   HARRIS             TX   PUBLIC

            PHOTO OF A PARTIALLY SUBMERGED STORE IN TOMBALL

&&

EVENT NUMBER HGX1700410

11

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
630 AM CDT MON AUG 28 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0518 PM     FLASH FLOOD      4 SW COVE               29.78N  94.87W
08/27/2017                   CHAMBERS           TX   EMERGENCY MNGR

            SH 99 NORTHBOUND AND SOUTHBOUND UNDERWATER VIA TXDOT
            BEAUMONT

&&

EVENT NUMBER HGX1700411

11

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
709 AM CDT MON AUG 28 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0223 PM     TORNADO          9 NE GALVESTON          29.31N  94.77W
08/25/2017                   GALVESTON          TX   PUBLIC

            PUBLIC REPORTS A FUNNEL CLOUD AND A METAL FENCE DAMAGED
            NEAR FERRY RD IN GALVESTON

&&

EVENT NUMBER HGX1700412

11