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Area Forecast Discussion (AFD)

Issued by Houston/Galveston, TX (HGX)

                            
000
FXUS64 KHGX 220235
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
935 PM CDT Sun Apr 21 2019

.UPDATE...
A weak boundary or dryline is sagging southeastward this evening
across north TX but should stall out across the Red River
Valley by the early morning hours. Additionally, partly cloudy 
skies have started to build in over the counties surrounding 
Matagorda Bay. Observations as of 9 PM show temperatures in the 
upper 60s to low 70s, with dewpoints in the upper 50s to low 60s. 
Light to moderate southeasterly flow, and dewpoint depressions 
between 5-10 degrees should limit the development of patch fog 
tonight. Otherwise, the forecast appears to be in good shape, 
only tweaks tonight were to account for trends in observations.

Hathaway

&&

.PREV DISCUSSION... /ISSUED 630 PM CDT Sun Apr 21 2019/ 

AVIATION [00Z TAF Issuance]...

VFR conditions are expected for the next 24 hours but there could
be some brief MVFR ceilings at KCLL in the morning. For now will 
keep cloud decks scattered with the thought the main ceilings 
will just be to the west of KCLL/KUTS over central Texas which 
could just clip these terminals for a time. More robust moisture 
return is expected tomorrow so should see a higher potential for 
MVFR ceilings going into Monday night into Tuesday morning.

Southeast winds will continue tonight and not completely 
decouple. Winds should be gusty again tomorrow afternoon.

Overpeck

PREV DISCUSSION /Issued 249 PM CDT Sun Apr 21 2019/...

Near Term...
Sunny, warm, and breezy this afternoon with south winds generally 
in the 15 to 20 mph range. Low-level moisture is gradually 
increasing with 60+ dw pts currently present along the coast. 
We will see cloud cover begin to increase overnight from the 
SW as moisture levels continue to increase. 

Short Term...
Expect max temps to warm to around 80 across inland areas on 
Mon and Tue. Will introduce slight chc pops to NW areas on Tuesday 
as the atmosphere begins to destabilize ahead of a slow moving 
mid/upper low over northern Mexico. By Wed, rain chances will 
increase from west to east as the slow moving upper level low 
deepens over Texas and a cold front approaches from the west.

Long Term...
Wed afternoon through early Thu morning, there will be a chance 
of severe thunderstorms and heavy rainfall across SE Texas as 
the mid-upper level low and trailing trough axis move across 
SE/E Texas. SE Texas will be in the favorable left exit region 
of a 90+ knot upper level jet max with a very unstable atmosphere 
in place E/SE of a slow moving cold front. Precipitable water 
values will peak around 1.8 inches in the warm sector ahead 
of the front, setting the stage for locally heavy rainfall.

Expect the precipitation to end from west to east on Thursday. 
A mid/upper level ridge will build from the S/SW and lead to a warm 
and dry period Fri through Sun. There are some differences between 
the ECMWF and the more aggressive GFS concerning the strength of the 
weekend upper level ridge. The forecast is trended towards the 
GFS with max temps reaching the mid 80s next weekend. 33

MARINE... 
A mainly moderate onshore flow is expected to persist for the 
next several days. Winds/seas are expected to flirt with caution 
levels through the period, especially across the offshore waters. 
For the afternoon package, will continue to carry caution flags 
across the nearshore waters through tonight and go ahead and extend 
caution flags for the offshore waters through Tuesday morning. The 
onshore flow persists until late Wednesday night or early Thursday 
morning when the next storm system and associated cold front moves 
through the area. Look for periods of showers and thunderstorms 
with this system, especially Wednesday night through Thursday morning. 
West to northwest winds will develop Thursday through Thursday night 
after the system moves on through, and there could be a brief period 
where caution flags might be needed for this developing offshore flow. 
Light to moderate north winds on Friday will become east to southeast 
on Saturday and Saturday night and then mainly southeast on Sunday 
with high pressure moving off to the east.  42

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      62  82  65  80  64 /   0   0   0  30  30 
Houston (IAH)              63  81  66  79  66 /   0   0   0  10  10 
Galveston (GLS)            68  75  69  75  69 /   0   0   0  10  10 

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 5 AM CDT Monday 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.

     SMALL CRAFT SHOULD EXERCISE CAUTION through late Monday night 
     for the following zones: 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.

&&

$$

Update...08