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Area Forecast Discussion (AFD)

Issued by Houston/Galveston, TX (HGX)

                            
000
FXUS64 KHGX 242105
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
405 PM CDT Wed Apr 24 2019

.DISCUSSION...
One lone storm across Brazos County is the only action in town
this hour. It appears that the cap is winning out and, with a slow
erosion of the morning overcast, early afternoon convective
temperatures that were likely in the lower to middle 80s were 
not achieved. All of the CAMs are keeping the bulk of the 
convection to our north, that wedge between our northern counties
and the I-35 corridor, over the next few hours. As the 250-3H jet
noses into south central Texas, anticipating that the scattered 
convection along the southern flank will become slightly better 
organized and sweep across the central CWA this evening. All 
threat modes will be possible with a potential QLCS. So, cannot 
rule out an isolated (northern county) tornado or downburst wind 
gust...pockets of large hail and slower moving northeastern- 
propagating cells putting down a quick 1 to 3 inches are all 
plausible scenarios. Confidence is higher on that the majority of 
the strongest weather will occur from just after the issuance of 
this AFD to and around Midnight tonight. 

As the open wave upper Southern Plains trough kicks out over the 
ArkLaTex tomorrow morning, the establishment of lower level west 
winds will scour out what is left of lingering showers and isolated
storms over the Galveston Bay/southeastern CWA. The next few days
will be very pleasant albeit much warmer with maxTs forecast to
reach the middle 80s Friday on into the weekend. Overnights will
cool back into the 60s under relatively drier air. A reinforcing 
shot of drier air will come in behind a dry northern boundary 
passage Friday. Backing high pressure will moving over the area 
early this weekend. This will provide mostly to partly sunny 
skies and a return flow by early Saturday that will strengthen 
through Sunday as the high stations itself over the southeastern
U.S.. 

An upper low moving out of the upper Baja and into the southern 
Rockies as an open wave trough Monday and Tuesday will be the
impetus to lowering western state pressures. This will maintain a
tight enough onshore gradient to allow a stout onshore flow, and
moisture pump, to persist through the late period. With no
discernible boundary or lack of any upper level forcing, slight 
rain chances will only exist due to streamer showers forming under
the mid-level cap within greater than 1.2 or 1.3 inch pwat air. 
31

&&

.MARINE... 
Moderate onshore winds in response to low pressure over central
Texas will weaken as the low moves northeast. The gradient will 
relax as the low departs. Seas will remain slightly elevated and a
SCEC will remain in place for the Gulf waters this evening. An 
upper level disturbance will produce scattered showers and 
thunderstorms late tonight with a few of the storms becoming 
strong with the potential for some gusty winds. The low will drag 
a cold front into the coastal waters early Thursday and winds will
become W and eventually NW. High pressure will build into North 
Texas Thursday and Thurs night with a light offshore flow in 
place. The high will drift east with onshore winds returning late 
Friday night with onshore winds persisting through the weekend. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      60  79  60  83  60 /  90  20   0   0   0 
Houston (IAH)              64  80  62  85  62 /  80  30   0   0   0 
Galveston (GLS)            67  80  68  80  68 /  90  50   0   0   0 

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION 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...Matagorda Bay.

     SMALL CRAFT SHOULD EXERCISE CAUTION through Thursday morning 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.

&&

$$

Discussion...31/43