Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
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518 FXUS64 KHGX 262330 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 630 PM CDT Fri Apr 26 2024 ...New AVIATION... .SHORT TERM... (This evening through Saturday Night) Issued at 331 PM CDT Fri Apr 26 2024 An upper level trough & associated surface low is currently tracking northeasterly across the Central/Northern Plains this afternoon. SE Texas has ample instability available this afternoon, with MU CAPE ranging from 2000-3000 J/KG and midlevel lapse rates of 7.5-8 DegC/km. PWs range from 1.3-1.6" and dewpoint are currently in the upper 60s to lower 70s. A 30-40 knot LLJ remains in place overhead, and should continue to bring gusty conditions across SE Texas tonight. 6km bulk shear values range from 25 to 40 knots across the north/northwestern portions of our CWA, near the Brazos Valley/Piney Woods area. Meanwhile, 1km SRH remains generally under 150 m2/s2. Thunderstorms, some severe, are currently ongoing near Central/Northeast Texas. High-res guidance suggests that the strongest forcing for these storms will remain further north, just outside of our CWA. Even still, it is possible that a few strong to severe storms develop over portions of the Brazos Valley/Piney Woods area late this afternoon through later tonight. SPC has this area under a Marginal (level 1/5) risk of severe weather throughout the remainder of today. If any storms do develop in this area, the main threats will be damaging wind, large hail, and possibly locally heavy rainfall. A cold front associated with the aforementioned system stalls out near Central Texas, allowing humid conditions to persist overnight as dewpoints remain in the upper 60s to lower 70s. This, with cloudy skies should keep lows for Saturday morning in the upper 60s to mid 70s. Another mid/upper level trough will dig into the Four Corners on Saturday, though once again the strongest forcing remains north of our area during this period. Slightly stronger capping and lack of forcing should keep rain chances slim across SE Texas during the daytime hours. A 30-40 knot LLJ will continue to bring gusty winds during the day, which could warrant the need for a Wind Advisory, mainly in areas along the coastline/barrier islands. Otherwise, highs should be in the 80s area-wide. The aforementioned upper level trough should fill NE across the Plains during the late afternoon/evening hours on Sunday. This will push the aforementioned stalled boundary towards SE Texas, which may produce isolated showers/storms over portions of the Brazos Valley heading into early Sunday morning. 03 && .LONG TERM... (Sunday through next Thursday) Issued at 331 PM CDT Fri Apr 26 2024 There are a number of features we will need to watch for Sunday and Monday. The first is the aforementioned frontal boundary that will slowly creep into our neck of the woods from the west on Sunday. The other is a mid/upper trough currently digging southward over western CONUS. We will also need to monitor smaller disturbances embedded in the flow the aloft that could further enhance lift. By Sunday, the trough is expected to take on a negative tilt, with its axis roughly extending from eastern Colorado down to central Texas. Mid/upper south-southwest to southwest shear will increase through the day on Sunday as a result. Meanwhile in the low levels, deepening low pressure over the central plains coupled with continued high pressure over eastern CONUS will steepen the LL gradient and enhanced deep moist LL onshore flow (sfc-850mb). You will feel this via a strong breeze and plentiful humidity. The confluence of these features are expected to result in scattered showers and thunderstorms on starting late morning / early afternoon on Sunday, continuing into the morning and possibly the afternoon on Monday. The Weather Prediction Center has put most of our region under a Marginal Risk (Level 1 of 4) of excessive rainfall while our northern counties are under a Slight Risk (Level 2 of 4). An isolated strong to severe thunderstorm cannot be ruled out in our northern counties on Sunday. Both the mid/upper trough and sfc low pressure system pull northeastward and gradually lose their influence over the area on Monday. Despite the loss of larger scale forcings, continued high PWATs and the presence of weak mid/upper disturbances may suffice for isolated to scattered showers and thunderstorms on Tuesday and Wednesday. Global models indicate a more well defined mid/upper shortave could bring a better chance of showers/thunderstorms on Thursday. However, the best lift may remain north and west of our region. Regarding temperatures, the forecast is pretty warm and humid with highs generally in the 80s with lows mostly in the low 70s. && .AVIATION... (18Z TAF Issuance) Issued at 1241 PM CDT Fri Apr 26 2024 CIGS should continue to scatter & lift this afternoon, with most locations expected to reach VFR levels. MVFR CIGS may linger in areas south of the I-10 corridor this afternoon. Isolated showers could develop in these areas too, through one or two isolated stronger storms cannot be completely ruled out. Isolated showers will also be possible further north (near KCLL and KUTS) as well, with a higher possibility of stronger thunderstorms for these locations. Southeasterly winds of 10-20 knots with gusts of 25-35 knots will be possible throughout the day, relaxing slightly this evening as MVFR CIGS fill back in from the coastline. MVFR conditions persist overnight into Saturday morning, with CIGS improving heading into the afternoon. 03 && .AVIATION... (00Z TAF Issuance) Issued at 627 PM CDT Fri Apr 26 2024 Coastal terminals at MVFR CIGs with all other terminals at VFR. Expect MVFR conditions to develop again tonight/overnight as low clouds fill into the area. VFR CIGs expected to return during afternoon hours with a repeat of MVFR CIGs expected again tomorrow night. Winds will remain gusty out of th SE the rest of today and into tomorrow with gusts to above 30 kts possible. && .MARINE... Issued at 433 PM CDT Fri Apr 26 2024 Strong onshore flow will continue through the weekend along with enhanced seas. Small Craft Advisories are in effect through Sunday morning. Minor coastal flooding cannot be ruled out Saturday morning of in the bays, particularly upper portions of bays. Scattered showers and thunderstorms are possible on Sunday and Monday. Onshore winds will gradually decrease late Sunday into Monday. However, there will likely be a lag in the decreasing seas. Therefore, it is possible that advisories will need to be extended into Monday for areas offshore. Moderate onshore flow is expected to persist through much of the upcoming week. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 73 85 73 82 / 20 10 20 80 Houston (IAH) 74 84 74 83 / 30 0 0 60 Galveston (GLS) 73 79 74 79 / 30 0 0 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...High Rip Current Risk until 9 PM CDT this evening for TXZ436>439. GM...Small Craft Advisory until 7 AM CDT Sunday for GMZ330-335-350- 355-370-375. && $$ SHORT TERM...03 LONG TERM....Self AVIATION...Adams MARINE...Self