Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
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183 FXUS64 KHGX 101131 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 631 AM CDT Fri May 10 2024 ...New AVIATION... .SYNOPSIS... Issued at 354 AM CDT Fri May 10 2024 Storms have come to an end for the night, and with a weak front passing through, we should see a short break of fair weather through the early weekend. Showers and storms return Sunday into Monday, however. This next bout will bring another chance for locally heavy rain, and perhaps strong to severe storms as well. There are plenty of details to iron out, but at this stage, here are a few main thoughts: - The weak front moving through early this morning will not meaningfully scour out moisture, and we`ll see moisture quickly work back in for this next round of storms. WPC highlights most of the area in a slight risk for excessive rain (threat level 2 of 4) on Sunday, and the eastern half of the area continues at that threat level on Monday. On both days, the remaining area not covered by the slight risk will be in a marginal risk (threat level 1 of 4) for excessive rain. - Recent heavy rainfall will continue to have some influence on the most vulnerable locations, as those spots will still have relatively more saturated grounds. Thresholds of concern for flash flooding will be lowest in the vicinity of Lake Livingston. Some area rivers and streams are still swollen, including ongoing flooding on the Trinity and Brazos rivers. - The potential for severe thunderstorms also exists, but specifics are less clear at this time than the potential for heavy rain. SPC highlights the western half of our area with a marginal risk (threat level 1 of 5) on Sunday. There is not yet enough confidence to highlight a threat area for any severe storms for Monday, but keep checking updated forecasts, as one may emerge if confidence in a particular scenario increases. && .SHORT TERM... (Today through Saturday Night) Issued at 354 AM CDT Fri May 10 2024 The midnight shift will take credit for killing off the day`s storms, as they pretty quickly moved off or came to an end not too long after we arrived! It`s also totally me, and not some modestly cooler and drier air filtering in behind a weak front, that will make for fair weather through virtually all of this portion of the forecast. Speaking of that front, it is getting to be that time of year where we call them cold fronts by convention, but the incoming airmass is already so heavily moderated by the time it gets here, that there is little to no change in afternoon highs, and even the nighttime lows don`t get to take too much of a nudge downward as we`re not even getting a big dip in dewpoints, either. But...this front has at least enough oomph from high pressure drifting across the Great Plains that it should clear the area entirely, and make it out onto the open waters of the Gulf of Mexico before stalling out, buying us at least a short break of fair weather that is a little bit cooler and drier. With the front still in the process of making its way through, that bit of cooler air today will be largely limited to the northernmost strip of the forecast area. Good news for Caldwell, B/CS, Madisonville, and Crockett. Not so good news for those closer to the Gulf on the coastal plain. Today should see a good amount of sun, helping daytime temps rise more effectively through the day, so highs still look to end up right around 90 degrees. At least dewpoints will be on their way down, so peak heat index values look to stay below 100 degrees. Tonight looks to be modestly cooler, and those away from the Gulf should see highs slip below 70 degrees, setting us up for a slightly cooler day Saturday, where highs look to only make it into the lower to middle 80s. Saturday isn`t all great news, though. The Plains surface high keeps on moving east into the Southeastern US, and that means the return of onshore flow. This will pretty quickly erase all trace of this nice little post-frontal stretch, and precipitable water values look to spend their time Saturday night increasing back above the 90th percentile. This is mostly table setting for Sunday and what my shift partner will be talking about in the next section of the discussion. But, in case things are a bit on the progressive side, I do bring in some slight chances of PoPs in the 15 to 20 percent range late Saturday night. && .LONG TERM... (Sunday through Thursday) Issued at 354 AM CDT Fri May 10 2024 A stalled boundary offshore will lift northward on Sunday, enhancing LL convergence and bringing ample LL Gulf moisture. Meanwhile aloft, a mid/upper trough will move from SW CONUS into W Texas, ejecting a 50-60 knot 500mb jet over our region along with a pesky train of vort maxes embedded in the flow. Trough induced lee-side LL cyclogenesis over Oklahoma will enhance deep LL moisture advection. Sunday`s PWATs are expected to easily exceed 2.0 inches. Global ensembles are aggressive with widespread 2.0+ inch PWATs while deterministic guidance suggest the possibility of over 3.0 inches near the aforementioned boundary as it pushes north. Therefore, it is no surprise that model guidance is indicating widespread showers and thunderstorms on Sunday. Given the moisture and synoptic parameters, areas of heavy rainfall will unfortunately lead to another risk of flooding. The Weather Prediction Center has placed most of our region under a Slight Risk (Level 2 of 4) of excessive rainfall, with the highest risk of heavy rainfall being north of I- 10. Widespread totals are expected to be on the order of 1 to 4 inches. But locally much heavier totals will be possible given the very high PWAT values. We also cannot rule out isolated strong to severe thunderstorms. Storm Prediction Center has most of our region under a Marginal Risk (Level 1 of 5) of severe thunderstorms. The primary concerns are damaging wind gusts and hail. The sfc low over Oklahoma pushes eastward Monday. An associated weak, trailing cold front will push southward, keeping a chance of showers and thunderstorms in the forecast. Guidance is generally less aggressive with PWATs on Monday. However, there still appears to be potential for PWATs to exceed 2.0 inches near the boundary. Therefore, locally heavy showers and thunderstorms will be possible on Monday as well. We finally dry things out on Tuesday. But this may be short-lived due to another round of UL disturbances progged to influence our atmosphere during the second half of the week. Regarding temperatures, most of the long term is expected to skew a little hotter than averages with inland afternoon highs well into the 80s (possibly around 90) when not rain cooled. Sunday may feature enough rain and clouds to keep our northern counties in the 70s while our southern counties only make it into the low 80s. Overnight lows are expected to average in the upper 60s to low 70s. && .AVIATION... (12Z TAF Issuance) Issued at 631 AM CDT Fri May 10 2024 MVFR still across most of the area, though VFR is beginning to emerge in the north as weak front pushes out over the Gulf. UTS and CXO begin in VFR, and anticipate they will stay that way, with rest of terminals joining through the rest of the morning. Light, north winds will veer more northeasterly as well, and strengthen to around 10 knots with gusts to around or just above 20 knots for much of the day. Some guidance indicating some fog potential pre- dawn Saturday...but currently leaning against this with a modest amount of drier air filtering in. && .MARINE... Issued at 354 AM CDT Fri May 10 2024 Winds will increase from the northeast behind a passing frontal boundary today. Patchy fog and areas of haze are possible through this afternoon. Winds will veer easterly and increase further on Saturday, resulting in a corresponding increase in seas. Winds veer to a southeasterly direction by Sunday. Caution flags will likely be warranted on Saturday and possibly needed on Sunday. Showers and thunderstorms are possible on Sunday into Monday. Brief period of offshore flow possible on Tuesday before onshore flow returns by Tuesday night. Shower and thunderstorm activity may return during the second half of the upcoming week. && .CLIMATE... Issued at 354 AM CDT Fri May 10 2024 For the third day in a row, a daily record high minimum temperature record has fallen at Hobby. Yesterday`s low temperature of 79 degrees breaks the old record of 78 degrees. That record dates back to 2022. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 84 65 83 67 / 0 0 10 20 Houston (IAH) 88 68 85 69 / 0 0 10 20 Galveston (GLS) 85 74 81 74 / 10 0 10 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...Luchs LONG TERM....Self AVIATION...Luchs MARINE...Self