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Area Forecast Discussion (AFD)

Issued by Houston/Galveston, TX (HGX)

                            
000
FXUS64 KHGX 181713
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1213 PM CDT Wed Sep 18 2019

.NEAR TERM [Through Today]...

Looking at satellite and radar trends it looks like there is a 
good drying trend over much of the area. TD Imelda has been 
wobbling over the Conroe/Huntsville/Livingston areas. Think most 
of the afternoon will be drier but looking for possibility of 
redevelopment. That may be an issue is the atmosphere has 
stabilized and recovery of the airmass to become unstable again 
may be a challenge. Tropical systems tend to re-generate 
convection overnight so we want to be cautious. That said there 
are some higher-res models showing high amounts of rainfall and 
these same models have been overdoing rainfall amounts for this 
system. Forecast leans more on HRRR/RAP/TX Tech WRF which seem 
more in line with WPC QPF. We may see an additional 6-10" of 
rainfall from Liberty Co north to San Jacinto and Polk co as well 
as areas across E Texas. This leaves lower amounts with a tight 
gradient in these amounts over Harris Co and Houston mainly a east
to west gradient. Higher rainfall to the east close to Liberty Co
with less rainfall towards Katy. We will watch new HRRR and RAP 
runs going forward and update the forecast accordingly.

Overpeck

&&

.PREV DISCUSSION /Issued 641 AM CDT Wed Sep 18 2019/...



.AVIATION...
Strong convection will probably affect KLBX and KGLS for the next
couple of hours with light rain and low ceilings persisting
elsewhere. Not confident at all with regard to future development
this afternoon. With weak low pressure pushing slowly north, feel
some convective bands will form on the east and south side. But
where and when??? Conditions will begin to slowly dry out this
evening from the southwest with a mix of IFR/MVFR ceilings over
northern TAF sites. 43


&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL)  74  89  75  89  74 /  40  50  50  50  10 
Houston (IAH)          77  85  77  87  76 /  80  70  40  60  20 
Galveston (GLS)        81  85  81  86  80 /  80  70  30  50  20 

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...Flash Flood Watch through Thursday morning for the following 
     zones: Brazoria Islands...Chambers...Coastal 
     Brazoria...Coastal Galveston...Coastal Harris...Coastal 
     Matagorda...Fort Bend...Galveston Island and Bolivar 
     Peninsula...Inland Brazoria...Inland Galveston...Inland 
     Harris...Inland Matagorda...Matagorda 
     Islands...Montgomery...Northern Liberty...Polk...San 
     Jacinto...Southern Liberty...Trinity...Walker...Wharton.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 7 PM CDT this evening 
     for the following zones: Galveston Bay...Matagorda Bay.

     Small Craft Advisory until 7 PM CDT this evening 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...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.

     SMALL CRAFT SHOULD EXERCISE CAUTION from 7 PM CDT this evening 
     through Thursday 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...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...
NEAR TERM...Overpeck