River Flood Warning 8, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
334 PM CDT Tue Apr 28 2020

.SHORT TERM [Through Wednesday Night]...

Well, there was a bit more shower and thunderstorm activity this
afternoon than expected. A weak shortwave and a little to no capping
has allowed storms to pop up and down across the area, and this is
expected to continue through around sunset. There will be a bit of a
lull in activity from sunset through around midnight, but then the
next round of thunderstorms is expected to begin to approach the
area. A line of strong to severe thunderstorms will quickly move
southward across the area tonight first moving through the northern
zones around 1 to 3am, then racing southward to the Houston Metro
area between 3 and 6am, and finally off the coast by 5 to 7am. This
is slightly later than previously thought as the TT-WRF and HRRR has
slowed the arrival a bit, but once the line gets going it should
speed through the area. The main threat continues to be damaging
wind gusts with the passage, but hail and an isolated tornado or two
is still possible. While severe storms will be possible across the
area, the higher chances will be north of I-10 with increasing
threat the further north you go.

After the passage of the line of storms in the early morning, the
rest of the day will feature clearing skies with a northerly wind.
High temperatures tomorrow will be in the mid 80s across the area,
then dipping down mid to upper 50s tomorrow night.

Fowler

&&

.LONG TERM...(Thursday through Tuesday)
A deep upper trough over the southern Great Lakes will allow upper
level ridging to expand over Texas. 500 mb heights will increase
and temperatures will slowly warm on Thursday into Friday. 850
temps warm up on Saturday into Sunday so surface temperatures
should also climb a bit and high temperatures will warm from the
lower 80's on the Thursday to the mid/upper 80's on Friday to the
lower/mid 90's Saturday through Tuesday. Heat index values will
warm to near 100 degrees Sunday/Monday. The upper ridge will
flatten as an upper trough tracks across the northern plains. The
upper trough will phase with a weak short wave over the Rockies to
carve out a deeper long wave trough over the eastern US. This will
allow a sfc cold front to cross the area on Tuesday night bringing
a chance of showers and also some cooler temperatures for the
middle of next week. 43

&&

.MARINE...

Moderate onshore flow with 4 to 6 foot seas are expected through
tonight ahead of an approaching cold front resulting in caution
flags continuing through the night. This line of storms will move
through the area during the early to mid morning hours on Wednesday
bringing strong gusty winds. This line of storms will usher in
northerly winds Wednesday afternoon, becoming moderate overnight
Wednesday possibly resulting in additional caution flags. Light
onshore flow will emerge through Friday, but this flow will increase
to near caution criteria again over the weekend.

Fowler

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      68  80  53  83  57 /  80  40   0   0   0
Houston (IAH)              70  82  58  83  60 /  80  70   0   0   0
Galveston (GLS)            71  81  66  79  71 /  50  80   0   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION through Wednesday morning
     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...Galveston Bay...
     Matagorda Bay...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...43