Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
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981 FXUS64 KHGX 132320 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 620 PM CDT Fri Sep 13 2024 ...New AVIATION... .SHORT TERM... (This evening through Saturday Night) Issued at 333 PM CDT Fri Sep 13 2024 The brief reprieve of slightly lower humidity levels is soon to come to an end as weak high pressure becomes situated over the Central Gulf, promoting the return of a seasonably normal onshore flow pattern. Latest models continue to indicate a surge of low-level moisture arriving onshore over the next 12-24 hours as a result of this pattern shift (GLS in fact has already reported a surface dew point of 80 this afternoon). This will be accompanied by an increase in tonight`s forecast low temperatures, with most of the area sitting in the mid to upper 70s. Warm and humid conditions prevail on Saturday, with much of the area poised to see highs in the mid/upper 90s and heat index values in excess of 100 during the afternoon. While this is unlikely to warrant a Heat Advisory, those with outdoor plans tomorrow should nonetheless consider necessary heat safety precautions, especially after a fairly long period of cooler and slightly drier weather. Rainfall chances remain very low, aside from the potential for a few late afternoon evening showers and storms across the Piney Woods associated with wrap-around moisture from the former Francine. Otherwise, forecast soundings continue to indicate the presence of a fairly stout subsidence inversion which should work to inhibit diurnal convection. Overnight lows on Saturday once again will sit in the mid to upper 70s. Cady && .LONG TERM... (Sunday through next Thursday) Issued at 333 PM CDT Fri Sep 13 2024 Ridging aloft remains in place through next week leading to a rather prolonged period of hot and dry conditions. There`ll be at least a couple of opportunities for some isolated showers/storms though. On Sunday, we`ll have a weak frontal boundary across portions of the Piney Woods from the remnants of Francine. Moisture convergence along this boundary will elevated low-level moisture, but the question is will it be able to overcome the subsidence inversion layer? I`m leaning towards no, but these things are never a guarantee so I`d put rain chances at 10-20% at most. While that`s going on, we`ll have remnants of what is now Tropical Storm Ileana in the Eastern Pacific drifting through Texas from west to east. This`ll bring increased low-level moisture from the west...but the same question/answer before applies. Isolated showers/storms can`t be ruled out early next week, but there is a far greater probability that you won`t see any rain. 850mb temperatures will remain well above the 90th percentile (GEFS) through next week, and with persistent subsidence mixing those above normal temperatures to the surface...we`ll see...well above normal temperatures at the surface. There is a slight downward trend as we go through the week though with high temperatures starting out in the mid to upper 90s then gradually becoming low to mid 90s. However, I wouldn`t be surprised to see those low to mid 90s get a slight upward nudge as we get closer...especially for portions of the Brazos Valley. With model trends showing dew points mixing out into the 60s each afternoon, the air should dry out enough to support slightly hotter temperatures. What`s driving this extended period of hot/dry weather? Well it`s Friday the 13th, so to stick with the spooky theme...the ghost of Francine (at mid-levels) will combine with possible development along the coast of the Carolinas develops into a cutoff low over the eastern CONUS. While that`s going on, an upper level trough with an embedded upper level low moves in from the western CONUS. Model trends are still pointing towards an omega block pattern developing midweek, which would keep the Central/Southern Plains in a perpetual ridging aloft pattern. So...don`t be too surprised if the forecast continues to trend hotter and drier for next week. Speaking of heat, we talked about the increased low-level moisture a little bit earlier. That moisture is going to stick around through the week, so we`ll be keeping an eye on heat indices. At the moment, we`re looking at heat indices of 103-107F at the most, which is below our threshold for a Heat Advisory ( 108F). It`ll definitely be hot enough to notice it though, so be sure to practice heat safety. On the plus side, next week is the last full week of astronomical summer. If we could pass along that message to Mother Nature, that`d be great... Batiste && .AVIATION... (00Z TAF Issuance) Issued at 610 PM CDT Fri Sep 13 2024 VFR conditions will generally prevail through with some SCT to BKN mid and high level clouds. There may be some patchy fog reducing visibility to 4-6 mi at times during the predawn hours at CXO (and possibly SGR and UTS), but any fog that develops will quickly dissipate after sunrise. Light and variable winds will continue through the night becoming west-southwesterly through the morning at around 6-10kt. The seabreeze will cause a southerly wind shift in the afternoon/evening at GLS, LBX, SGR, HOU, and possibly all the way up to IAH. Fowler && .MARINE... Issued at 333 PM CDT Fri Sep 13 2024 Benign marine conditions will continue with light onshore winds and low seas prevailing through the weekend and into next week. Isolated showers/storms will be possible going into early next week across the Gulf waters. Batiste && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 75 98 74 98 / 0 10 10 10 Houston (IAH) 77 96 76 96 / 0 10 10 10 Galveston (GLS) 80 88 77 87 / 0 0 0 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...Cady LONG TERM....Batiste AVIATION...Fowler MARINE...Batiste