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Area Forecast Discussion (AFD)

Issued by Houston/Galveston, TX (HGX)

FXUS64 KHGX 260125

Area Forecast Discussion
National Weather Service Houston/Galveston TX
825 PM CDT Sun Aug 25 2019

.SHORT TERM [Overnight]... 

Have lowered pops and cleared much of the sky cover from the 
overnight forecast. Still a chance for showers near the coast 
after 4 am. 


.AVIATION [00Z TAF Issuance]...
VFR except for a narrow band near LBX/GLS where ceilings around
1500-2200 feet have developed. Reintroducing VCSH and PROB30s for
the coastal areas after 10z and then 15z further inland including
the Metro hubs. Monday looks to have much less coverage than
occurred today. 


.PREV DISCUSSION /Issued 338 PM CDT Sun Aug 25 2019/...

Showers and thunderstorms continue to develop this afternoon in 
response to a strong short wave trough over the Ozark plateau, 
deep tropical moisture and favorable upper level jet dynamics. The
jet dynamics become increasingly less favorable as the upper 
trough shifts east and upper level winds become confluent. That, 
coupled with the loss of heating should allow precip to wane 
rather quickly this evening.

A 595 dm upper level high becomes centered near El Paso on Tuesday
with the ridge expanding eastward into East Texas. 850
temperatures warm and high temperatures will once again be near
100 out west to the mid 90's central. Fcst soundings show some
capping in the morning that erodes in the afternoon. Convective
temps are around 95 degrees so there could be some isolated
showers around despite some modest subsidence. The center of the 
upper ridge retreats toward AZ on Wednesday and 500 mb heights 
fall a little leaving SE TX on the periphery of the high. PW 
values reach 2.00 inches by afternoon and convective temps again 
look reachable. The ECMWF is the most aggressive in bringing a 
weak front into the area on Weds afternoon and this boundary 
could also serve as a focus for shra/tsra. The pressure rises 
behind the front are weak so not expecting the front to make it to
the coast and it will likely stall somewhere over the CWA if it 
even makes it this far south. Will again carry lowish PoPs Wed 
into Thu for isolated/scattered activity.

Things become rather muddled by the end of next week and into the
weekend. At this time, it appears a tropical wave or perhaps a
weak area of low pressure will try to organize over the central
Gulf. Too soon to know where this system will track or potential
impacts but we are approaching the peak of the tropical season and
it's always a good idea to check preparedness plans and remain 
prepared. 43

High moisture within a continued unsettled maritime environment will 
likely allow for the redevelopment and continuation light rain, 
scattered showers and/or embedded thunderstorms. High pressure over 
the northern Gulf will maintain a generally weak onshore wind field 
through the week. In the near term, the slight deepening of a more 
north-south orientated Texas Panhandle low pressure trough will 
create a tight enough onshore pressure gradient back to the western 
Gulf to produce moderate southerlies early tomorrow. Caution level 
winds over the nearshore Gulf waters are very probable Monday 
morning. Overnight Tuesday morning winds may also perk back up to 
around Caution criteria mainly due to the localized mix down of 
slightly stronger mid level winds. Early week average sea heights 
will gradually pick up by another foot or so, to 3 to 4 feet, but 
then fall back to around 2 to 3 feet mid to late week. Mid to late 
week high pressure at all levels will maintain weak onshore winds 
and low seas. 31



College Station (CLL)  78 100  79 101  77 /  10   0   0  10  10 
Houston (IAH)          79  98  80  99  79 /  10  30   0  20  10 
Galveston (GLS)        83  92  84  94  84 /  30  30   0  10  10 



TX...Heat Advisory from 1 PM to 7 PM CDT Monday for the following 
     zones: Austin...Brazos...Burleson...Colorado...Fort 
     Bend...Grimes...Houston...Inland Brazoria...Inland 
     Harris...Inland Jackson...Inland 

     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...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.