Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KHGX 191604
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1104 AM CDT Thu Sep 19 2019

.SHORT TERM [This Afternoon]...
Messy overnight weather shifting into messy morning and afternoon
weather for a good portion of the FA. Large band of thunderstorms
(MCS) that was draped over the central/southeastern counties last
night/early this morning has been slowly sinking S/SE and filling
in from the west this morning (along the coast). Some of the near
term models are indicating that these trends will continue and we
could see additional rounds of rain over areas that got a hit yes-
terday (particularly Galveston/Brazoria/Harris/Chambers counties).
Some incredible rainfall totals/rates have been reported thus far
and, unfortunately, we`re not really seeing signs of things taper-
ing off just yet. Main message is to stay put if you can and keep
up to date on the latest weather developments. 41

&&

.AVIATION [18Z Issuance]...
Will be keeping with the mention of TSRA for the rest of this aft-
ernoon/early evening...likely improving things after 01Z. Will be
hard-pressed to not include at least VCTS for most sites tomorrow
afternoon. Overnight issues could include MVFR/IFR CIGS. 41

&&

.PREV DISCUSSION...  /ISSUED 502 AM CDT Thu Sep 19 2019/

Persistent band of storms initiating over parts of Montgomery
county extending through Liberty and parts of northeastern
Chambers county toward Beaumont have been producing extremely
heavy rainfall with rainfall rates of 3-5"/hour amounts. VWP
clearly showing the deep rich moisture transport into the cell
development...25-49 knots of inflow! Dewpoints of 80 at Galveston
and PW estimates 2.2-2.4" feeding these storms.

Flash flood emergency in effect in Liberty/Chambers/Jefferson/Orange
counties already this morning and given the rates and previous
rainfall these will likely be extended and may need to be
expanded. Rainfall totals in Liberty/Chambers county this morning
over the last 3 days is 6-10" with some of the hardest hit areas
having gotten more than 25"!

Have expanded the Flash flood watch to the west-northwest with the
expectation that storms should initiate and expand west and
northwest from the current storms possibly clipping the northern
portions of Harris. The HRRR of late has been doing a good job
with the pattern though perhaps slightly shifted in location. Then
expecting the storms to expand further both south and north
through mid day well into the Metro. Rainfall rates may start to
come down at least a bit this afternoon as inflow relaxes
somewhat.

Overnight storm threat shifting north tonight and may be focused
more in the College Station to Groveton corridor but mesoscale
features could and may well mess with that expectation. Tonight
the moisture transport relaxes as well...the one concern at this
point will likely be the slow storm motion.

Rain chances tapering down for a few days over the weekend but
then next big surge of moisture arrives Monday and some
indications of weak coastal troughing. Will be keeping an eye on a
wave coming in from the Caribbean Monday and Tuesday probably
arriving in the central Gulf Tuesday/Wednesday. We certainly
wouldn`t need this on the heels of Imelda.

45

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      85  75  90  74  90 /  90  70  50  10  20
Houston (IAH)              82  77  87  76  89 / 100  50  70  10  30
Galveston (GLS)            85  81  86  81  86 /  60  40  60  10  20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flash Flood Watch until 7 PM CDT this evening for the following
     zones: Austin...Brazoria Islands...Brazos...Burleson...
     Chambers...Coastal Brazoria...Coastal Galveston...Coastal
     Harris...Fort Bend...Galveston Island and Bolivar
     Peninsula...Grimes...Inland Brazoria...Inland Galveston...
     Inland Harris...Montgomery...Northern Liberty...Polk...San
     Jacinto...Southern Liberty...Trinity...Walker...Waller...
     Washington.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 7 PM CDT this evening
     for the following zones: Coastal waters from Freeport to
     Matagorda Ship Channel TX out 20 NM...Matagorda Bay...
     Waters from Freeport to Matagorda Ship Channel TX from 20
     to 60 NM.

     Small Craft Advisory until 7 PM CDT this evening for the
     following zones: Coastal waters from High Island to
     Freeport TX out 20 NM...Galveston Bay...Waters from High
     Island to Freeport TX from 20 to 60 NM.

&&

$$


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.