050 FXUS64 KHGX 312307 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 607 PM CDT Sat Jul 31 2021 .AVIATION... Showers and thunderstorms will wane with the loss of heating and generally clear skies are expected overnight. A few showers will begin to redevelop prior to sunrise along the immediate coast and will carry a VCSH for KGLS. Daytime heating will once again serve as a catalyst for additional shra/tsra on Sunday afternoon and will carry a VCTS for TAF sites between 18-23z. 43 && .PREV DISCUSSION... /ISSUED 321 PM CDT Sat Jul 31 2021/ SHORT TERM [Tonight Through Sunday Night]... For most of the area, temperatures have risen into the middle 90s with heat indices in the lower to middle 100s. The seabreeze has just about made it to I-10, with a handful of showers and thunderstorms popping up, mostly in the Galveston Bay area. Between the cooler Gulf air and scattered rain, temperatures on the coast have slipped just below 90 degrees. Scattered showers and storms are expected to continue in the vicinity of the seabreeze front through the rest of the afternoon and into the early evening before dissipating as the sun begins to set. This means convection probably is probably out of the question north of the Houston metro, and really...even northern parts of the metro are probably seeing any chance at showers or storms dwindle. Expect another warm, mostly clear night tonight - and for some, that may be the last such night for a little bit, but I'm getting a touch ahead of myself right now. Anyway, tomorrow looks very much to be a persistence type of day. I'll leave the choice to the midnight shift, but if my forecast verifies perfectly (yes, please!) - the northeastern counties who had a heat advisory today would need another tomorrow. Elsewhere, just like the last several days, the bulk of the area looks to see the heat index come in juuuuuust underneath the advisory threshold. And I'm sure you're all getting sick of me saying this, but yes - even typical summertime heat here can be dangerous if you're not cognizant of heat illness threats, but can be avoided with just a little forethought and prep. Now, back to tonight being the last of its type for a bit. The big ridge that's been dominating much of the US for the past several days? Finally going to weaken, while a deep upper trough drops into the Great Lakes and digs all the way down to the south. Come Sunday night, a surface low over upstate New York will drop a cold front that will extend all the way into East Texas, and looks to end up just north of our forecast area by the end of the night. So, at the coast, Sunday night probably really isn't going to be much different. Maybe a bit more cloudiness, but still fair weather and pretty warm. But in the northern part of our forecast area, rather than see the sky clear out overnight, cloud cover will stay higher, and even increase. Rain chances should wane for a handful of hours in the evening and early overnight as the day's sun-fueled showers and storms come to an end, but will ramp back up later overnight as the front drops nearer to the area and lift increases. Troughing aloft doesn't look to be super strong so far removed from the main vort lobe, but we'll see some midlevel height falls and surface convergence along the front to help boost rain chances. One thing we definitely won't be lacking is moisture, with precipitable water values around the 90th percentile per NAEFS. Some deterministic guidance suggests moisture pooling near the front could mean PWATs eventually start to push 2.5 inches. Luchs LONG TERM [Monday Through Saturday]... Expecting backdoor cold front to drop down from the NE into SE TX Monday as a broad upper trough deepens over the Eastern half of U.S. This boundary and associated lift will focus a band of showers and thunderstorms starting Monday morning northern counties...working its way south into coastal counties Monday afternoon and evening. The front then stalls out near or a little inland of the coast leading to continued wet conditions Tuesday for all zones...and Wednesday especially near and south of I10. Some drier air may filter in Wednesday for inland/northern counties leading to a break in the rain there. This break could extend to the coast Wednesday night and Thursday depending on where front stalls out. The timing and ultimate southern extent of frontal progression...and the associated rain chances Wednesday and Thursday...remain a lower confidence part of the forecast. Front washes out Friday and Saturday with a return to onshore flow and more of the diurnal thunderstorm activity we've been seeing with thunderstorm chances starting near the coast in the morning and progressing inland with the sea breeze as the day wears on. Reilly MARINE... Fairly modest winds and seas are expected through period with light to occasionally moderate south to southwest winds this weekend...becoming variable on Tuesday...then possibly northeast Tuesday night and Wednesday as a weak backdoor front becomes drops down from the N then becomes nearly stationary near the coast. Exact timing and location of this front still uncertain. The front will lead to an increase in shower and thunderstorm activity. Locally higher winds and seas are expected in and near thunderstorms. Will likely see more typical onshore flow set up late Friday and Saturday as the front dissipates. Reilly && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 77 97 77 93 74 / 0 20 30 60 40 Houston (IAH) 78 97 78 95 76 / 20 30 20 60 60 Galveston (GLS) 82 92 82 92 80 / 10 30 20 50 60 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$