Area Forecast Discussion
Issued by NWS Houston/Galveston, TX
Issued by NWS Houston/Galveston, TX
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021 FXUS64 KHGX 272038 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 338 PM CDT Sat Apr 27 2024 ...New SHORT TERM, LONG TERM, MARINE, CLIMATE... .SHORT TERM... (This evening through Sunday Night) Issued at 337 PM CDT Sat Apr 27 2024 A mid/upper level trough over the Four Corners should fill NE across the Plains this evening. The tight gradient and 30-40 knot LLJ should continue to bring windy conditions across SE Texas overnight. Expect winds to be south/southeasterly around 15-25 mph with gusts of around 25-35 mph. Therefore, a Wind Advisory will remain in effect for most areas south of the I-10 corridor through 7 PM CDT Tonight. For the barrier islands east of Freeport, the Wind Advisory will remain in effect until 7 AM Sunday. Persistent onshore flow with ample moisture and cloudy skies should keep lows for Sunday morning in the 70s across SE Texas. A cold front/dry line associated with the aforementioned upper level system will approach the Brazos Valley late Sunday morning. As it nears our area, the pressure gradient will weaken, reducing wind speeds & gusts. Isolated storms should begin to pop up during the afternoon ahead of this boundary. During the late afternoon/early evening, guidance indicates a more cohesive line/cluster of thunderstorms developing along a weaker boundary, tracking E/SE overnight. The environment for these storms still appears to be fairly potent. ML CAPE values during the late afternoon rise to around 2100-2800 J/KG in areas east of I-45, in excess of 3000 J/KG in areas to the west. LIs peak around -6 to -10 Deg C, with mid level lapse rates ranging from 6.5-8.5 Deg C/km. ML LCL heights will be under 1000m. Effective shear (EBWD) will range from 35-45 knots, with 3 km SRH ranging from 100-250 m2s2. PWs remain near 1.6-1.9 inches. Currently SPC has areas north of the I-10 corridor under a Slight (level 2/5) Risk of severe weather on Sunday, with the remainder of SE Texas under a Marginal (level 1/5) Risk. These storms appear to take on more of a discrete storm-mode, capable of producing all severe weather hazards. Damaging winds and large hail remain the primary hazards, but an isolated tornado cannot be ruled out. These storms will also be capable of producing locally heavy rainfall. WPC has the northern third of our CWA under a Slight (level 2/4) Risk of Excessive Rainfall for Sunday, with areas to the south partially under a Marginal (level 1/4) Risk. Rainfall totals through Monday morning are expected to range from 0.5"-2.25" with locally higher amounts up to 4" possible with any slower-moving storms. The severe weather & heavy rainfall threat should decrease overnight as the boundary pushes further south, displacing these storms further from the upper level trough, reducing the already weak forcing aloft. This weak/diffuse boundary should slow/stall out around the I-10 corridor, through conditions will still be fairly warm/humid across the region Mondary Morning. 03 && .LONG TERM... (Monday through next Friday) Issued at 337 PM CDT Sat Apr 27 2024 Periods of showers and thunderstorms will remain in the forecast as a series of disturbances/impulses/shortwaves move across the state in a generally west to southwest flow aloft while onshore winds remain in place. Enough instability could persist on Monday for possible strong/severe storms (Marginal Risk on SPC`s Day 3 Convective Outlook) and locally heavy rain (Marginal Risk on WPC`s Excessive Rainfall Outlook). For the rest of the period, could see shower/storm development almost any day with better chances generally across our northern counties. High temperatures will be in the 80s and lows will be mainly in the 70s. 42 && .AVIATION... (18Z TAF Issuance) Issued at 1226 PM CDT Sat Apr 27 2024 Cloudy skies and VFR to MVFR CIGS can be expected across SE Texas this afternoon. MVFR CIGS should fill in across the region again this evening, with south/southeast winds of 15-20 knots and gusts of 25-30 knots prevailing overnight. Winds relax slightly Sunday morning as the gradient weakens ahead of an approaching frontal boundary. Isolated showers/storms could develop during the afternoon hours ahead of this boundary. Expect more numerous storms during the late afternoon/evening on Sunday, especially north of the I-10 corridor. Some of these storms could become strong to severe at times. 03 && .MARINE... Issued at 337 PM CDT Sat Apr 27 2024 Moderate to strong onshore winds (15 to 25 knots with gusts >30 knots) and elevated seas (10 to 12 feet offshore) will continue through the weekend. Small Craft Advisories are in effect through Sunday. Minor coastal flooding is possible in vulnerable locations at times of high tide. Rain chances increase on Sunday with scattered showers and thunderstorms persisting into Monday. Winds will gradually decrease late Sunday into Monday, with lingering high seas keeping conditions dangerous to small craft through Sunday night. Though more moderate, onshore flow will persist early next week. 42 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 73 82 69 85 / 10 80 70 20 Houston (IAH) 74 84 70 85 / 10 50 60 60 Galveston (GLS) 73 80 72 80 / 0 40 40 60 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Wind Advisory until 7 PM CDT this evening for TXZ214-226-227- 235>238-300-313-335>338-436. Beach Hazards Statement through Sunday evening for TXZ436>439. Wind Advisory until 7 AM CDT Sunday for TXZ437>439. GM...Small Craft Advisory until 10 AM CDT Sunday for GMZ330-335. Small Craft Advisory until midnight CDT Sunday night for GMZ350- 355. Small Craft Advisory until 5 AM CDT Monday for GMZ370-375. && $$