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Area Forecast Discussion (AFD)

Issued by Houston/Galveston, TX (HGX)

FXUS64 KHGX 220013

Area Forecast Discussion
National Weather Service Houston/Galveston TX
713 PM CDT Wed Aug 21 2019

.AVIATION [00Z TAF Issuance]...

Isolated/widely scattered convection that formed earlier today has
all but dissipated at this time. A few straggling showers are try- 
ing to move in from the NE at present, but these probably will not  
last too much longer. The rest of tonight should be quiet with VFR
conditions prevailing. Otherwise...not going with a lot of changes
from previous TAF trends as we remain in the same pattern of these
last few/several days. Activity over the coastal waters during the
very early morning hours will be moving inland by the afternoon...
with development fueled by daytime heating and the seabreeze. Once
again, things to quiet considerably by Thurs evening. 41


.PREV DISCUSSION... /ISSUED 352 PM CDT Wed Aug 21 2019/ 

SHORT TERM [This Afternoon through Thursday]...

Showers and isolated thunderstorms are currently developing mainly 
south of I-10 and east of I-45, and are expected to gradually move 
north to northeast as the afternoon progresses. This activity is 
expected to dissipate by the evening with the loss of heating. For 
tonight, expect clear to partly cloudy skies with low temperatures 
ranging in the mid 70s to low 80s. Passing showers are possible over 
the Gulf waters late tonight to early Thursday morning, and could 
move into the coastline from time to time. 

Thursday, light southerly wind flow and high temperatures ranging in 
the low to upper 90s expected. Mid to upper level ridge will start 
to retreat to the west, decreasing subsidence across southeast 
Texas, as an upper level trough moves across the Great Lakes region. 
 Deep low level moisture is expected to begin to move into the 
region, but should remain mainly along the Gulf waters and southern 
counties throughout the day. Data shows PWAT values between 2.00 to 
2.25 inches lingering across the aforementioned areas starting 
Thursday morning through Thursday evening. Elsewhere, PWAT values of 
1.40 to 1.90 inches expected. With the ridge further west and low 
level moisture gradually increasing across the Gulf and southern 
regions, expect showers over the Gulf waters and coastal regions in 
the morning, followed by showers and thunderstorms developing across 
the southern and central regions during the late morning and 
afternoon hours. Most of the activity is expected to dissipate in 
the evening. However, showers and thunderstorms are expected to
continue over the local waters...occansionally moving into the 
coastal areas throughout the night. Low temperatures will remain 
in the mid 70s to low 80s. 24 

LONG TERM [Friday through Tuesday]...

Chances of shower and thunderstorms activity will increase 
Friday. Mid to upper level trough will slowly move across the 
Great Lakes region and the ridge will remain west of Texas Friday.
Deep low level moisture will continue to filter into the Gulf 
water and southern regions of southeast Texas, moving further 
north as the day progresses. PWAT values between 1.70 and 2.30 
inches should encompass the region by Friday afternoon, 
particularly along the southern and central regions. PWAT values 
of 2.20 to 2.50 inches is expected to remain mainly over the Gulf 
waters. Expect shower and thunderstorm activity to continue over 
the Gulf waters and southern portions of southeast Texas early 
Friday morning. As the day progresses, shower and thunderstorm 
coverage and intensity will increase and expand further inland. 
Strong storms will be capable of producing periods of heavy 
rainfall, frequent lightning and gusty winds. The heavy rainfall 
could lead to ponding of water along roadways and areas of poor 
drainage as well as reduced visibility. 

For the upcoming weekend, a similar pattern looks to set up with 
the deep low level moisture lingering over the Gulf waters as well
as the southern and central regions. Additionally, an upper level
disturbance or shortwave will move eastward across central CONUS 
and north of Texas Saturday, elongating southward into the eastern
TX and LA region Sunday. On Monday and Tuesday, low level 
moisture is expected to decrease, however, the proximity of the 
upper level trough could continue to enhance shower and 
thunderstorm activity across southeast Texas, mainly in the
afternoons. Expect periods of showers and thunderstorms along the
Gulf waters and southern and central regions throughout the day, 
with lighter activity developing over the northern regions. At 
nighttime, activity is expected to dissipate inland and persist 
mainly over the waters and coastal regions. High temperatures will
range in the mid to upper 90s north of I-10 and in the low to mid
90s south of I-10 each day. Low temperatures will range in the 
mid 70s to low 80s. A southerly wind flow is expected to prevail 
throughout the forecast period. 24


College Station (CLL)      76  99  76  97  76 /   0  10  20  30  10 
Houston (IAH)              78  95  78  93  78 /  10  20  40  60  30 
Galveston (GLS)            83  91  82  89  82 /  10  40  60  70  60