Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 230440
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1140 PM CDT Sat Jul 22 2017

.AVIATION...
An upper low over the western Gulf will meander near the coast
into Sunday and some showers will be possible along the immediate
coast toward sunrise Sunday morning. Daytime heating will trigger
another round of afternoon storms...impacting mainly the Houston
terminals and KCXO and KSGR. Convective temps on Sunday are around
89 degrees and PW values will reach 2.15 inches by 21z with
soundings showing a weak capping inversion developing near 850 mb
but this looks breakable during peak heating. Shra/Tsra will
dissipate quickly Sunday evening with the loss of heating. A
fairly thick mid/upper cloud deck will linger over the area Sunday
night. 43

&&

.PREV DISCUSSION... /ISSUED 919 PM CDT Sat Jul 22 2017/

UPDATE...
Earlier evening convection has dissipated, with northern portions
of Harris County receiving anywhere from 1 to up to 3 inches.
Cannot rule out a few more isolated showers and maybe a
thunderstorm or two along the coastal counties and across the
coastal waters tonight as a mid to upper level weakness evident on
evening RAOBs meanders across the area, but have low confidence
on how far inland this activity will actually push given
increasingly southwest low level flow in response to surface
ridging over the northern Gulf. As a result, have lowered rain
chances inland for night while maintaining 20 PoPs along the coast
and for the waters. Otherwise, made minor updates for hourly
trends with overnight lows in the mid 70s to low 80s.

Huffman

PREV DISCUSSION... /ISSUED 351 PM CDT Sat Jul 22 2017/

DISCUSSION...
Precipitation not quite as widespread across SE TX this afternoon
likely owing to the extensive clouds and persistent storms
offshore (limiting stability and preventing decent inflow
respectively). While temperatures have been a touch lower than
yesterday, the higher dewpoints are keeping heat index values
elevated (100-106F) so far today.

With the upper low lingering around the coast between GLS and LCH
through tomorrow am a bit hesitant to lower POPS too much...especially
for our eastern and coastal counties. Progged PWs from 2.0 to 2.2
inches do appear supportive of some decent rains tomorrow.

However...do agree that the main issue with the upcoming forecast
could be the rising heat/heat indicies for next week. As this low
washes out, we should see the upper ridge out west begin building
east into the Central/Southern Plains. Rain chances will decrease
starting Monday save for some isolated development at or along
the seabreeze. Daytime highs are progged to be in the upper
90s to around 100 for central/northern parts of our CWA, and with
dewpoints remaining in the 70s, this could translate to heat
index values at or near our heat advisory criteria of 108
degrees. 41

MARINE...
The upper level low pressure system is continuing to fill into the
region and aid in the development of showers and thunderstorms this
afternoon. Although coverage this afternoon has diminished in
comparison to this mornings convection, lingering showers and an
isolated thunderstorm or two can be expected over the waters through
the remainder of this evening. Gusty winds can also be anticipated
with these stronger storms. Onshore flow overnight will begin to
increase in wind speed as the pressure gradient tightens over SE TX
Sunday into Monday. Winds should increase to between 10-15 knots
tonight and hold through Sunday. Sunday night into Monday winds
again will pick up in speed and stay closer to 15 knots before
diminishing late morning on Monday. Therefore, we will be flirting
with SCEC criteria while this tighter pressure gradient holds place.
Seas will also pick up during this time from 2 feet to 2-4 feet. By
Tuesday an area of high pressure begins to build in resulting in a
lowering in wave height and weaker onshore flow. Conditions will
also be drier through next Friday.

Hathaway

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      77  95  77  98  76 /  10  30  20  10  10
Houston (IAH)              79  91  80  96  78 /  10  50  30  20  10
Galveston (GLS)            82  88  84  91  82 /  20  50  20  20  10

&&

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

$$

Discussion...14
Aviation/Marine...43


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