Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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626 FXUS64 KHGX 162037 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 337 PM CDT Sun Jun 16 2024 ...New SHORT TERM, LONG TERM, MARINE... .SHORT TERM...
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(This evening through Monday Night) Issued at 257 PM CDT Sun Jun 16 2024 As we head into the beginning of the upcoming week, we will enter into a period of active weather that will be characterized by widespread, occasionally heavy rainfall which could lead to flooding along area rivers, streams and bayous as well as some street flooding. Global models continue to show cyclogenesis in the Bay of Campeche overnight tonight, likely leading to the development of a weak closed low by the early hours of Monday. This feature, as well as a developing lee cyclone to our northwest, will produce a tighter synoptic pressure gradient and thus a stronger onshore flow regime that will bring a plume of deeper tropical moisture to the area. With an associated midlevel trough providing some vorticity advection along with the impacts of diurnal heating, we will begin to see shower/thunderstorm activity pick up across the area overnight into the early hours of tomorrow and expand in coverage during the afternoon. Any stronger storms that develop will have the potential to tap into relatively deep moisture (PWs > 2.0 in by Mon afternoon) and produce some locally heavy downpours. As such, the WPC has maintained a Slight Risk of Excessive rainfall roughly along and south of the Hwy 59 corridor. Urban and poor drainage areas may see some localized street flooding depending on the location of any stronger developing storms. Otherwise, rainfall totals will generally sit around an inch south of the 59 corridor and less across the northern zones. Temperature wise, increasing cloud cover along with the impacts of afternoon rainfall may keep highs from exceeding 90 for much of the area, especially closer to the coast. Despite this, dew points in the mid 70s will still contribute to heat stress as heat indicies once again reach the century mark. Overnight lows, bolstered by WAA and greater cloud cover, will sit in the mid to upper 70s inland and near 80 along the coast. Cady
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&& .LONG TERM...
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(Tuesday through next Saturday) Issued at 257 PM CDT Sun Jun 16 2024 A closed low is expected to develop in the Southwestern Gulf by Tuesday. Combined with high pressure/ridging spanning the eastern sea board, this will greatly tighten the pressure gradient, setting up a 30-40 knot LLJ over portions of the Texas/Louisiana coast. Converging winds along the coastline & forcing from this system, in combination with deep moisture (PWs in excess of 2" at times), will result in numerous storms across the Northwestern Gulf throughout the first half of the week. Forecast soundings during this period feature deep saturation, with a warm cloud layer in excess of 15,000 ft, still indicative of high precipitation efficiency necessary to produce heavy rainfall. WPC has a Moderate (level 3/4) to Slight (level 2/4) Risk of excessive rainfall over SE Texas for Tuesday through Wednesday. These storms will be capable of producing heavy rainfall, with areas south of US-59 most at risk for heavy rains and flooding (denoted by the Moderate Risk area). This includes the Houston Metro area, with urban locations such as these already prone to flooding due to poor drainage. Areas south of US-59 could see rainfall totals of 5-8 inches with isolated higher amounts possible. Areas to the north will generally receive 2-4 inches during this same period. This rainfall will likely result in rises in rivers, streams and creeks. Additionally, strong winds and long fetch induced by this system may result in moderate coastal flooding as well. Some uncertainties still remain in the forecast, mainly with the track of the system. It`s important to remember that even small deviations in the expected path of this system can greatly shift where the heaviest rain falls. Regardless, confidence in tropical development is growing, and NHC now has a 70% chance of this system becoming a tropical cyclone within the next 7 days. Impacts from this low will still be felt across SE Texas, regardless of if it becomes a named cyclone. The heavy rainfall threat diminishes on Thursday as the aforementioned system tracks into Mexico and dissipates. However, wet conditions look to continue through the end of the week as a broad upper level low traverses through the Gulf of Mexico. An upper level high over portions of the Southern Plains looks to keep that next disturbance restricted to the Southern Gulf, thus limiting it`s impacts to SE Texas. 03
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&& .AVIATION... (18Z TAF Issuance) Issued at 1246 PM CDT Sun Jun 16 2024 The current TAF period will begin a period of deteriorating conditions that will likely last several days. For the remainder of today and into tonight, VFR conditions are expected to prevail with winds remaining around 5-10 knots. Shower and thunderstorm activity will begin to increase after around 09Z tomorrow morning, with rainfall beginning along the immediate coast and expanding inland over the course of the day. This will be accompanied by an increasing SE wind, with wind speeds reaching around 10-15 knots with gusts occasionally in excess of 20 knots. Any stronger storms that do develop may produce the occasional stronger wind gust and/or visibility reduction, but in general cigs are expected to remain in the MVFR range. Cady && .MARINE...
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Issued at 257 PM CDT Sun Jun 16 2024 Winds and seas will increase over the next several days as the pressure gradient tights from a developing low over the Southwestern Gulf of Mexico. Ample Gulf moisture will bring numerous showers/storms daily, beginning later tonight into the upcoming week. Small Craft Advisories take effect on Monday and will likely be extended over the next several days as winds approach 20 to 30 knots with gusts in excess of Gale-Force possible. Seas are expected to reach 10 to 15 feet at times. These strong onshore winds over a long fetch will also bring a high risk of rip currents and potentially moderate coastal flooding across the Texas coastline as early as Tuesday. Forecasted winds and seas may vary depending on how this system evolves. Gale warnings cannot be completely ruled out at this time. Stay tuned over the next several days as we monitor this system. Conditions begin to improve on Thursday as the aforementioned tropical system dissipates over Mexico, with winds and seas falling below Small Craft Criteria on Friday. 03
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&& .PRELIMINARY POINT TEMPS/POPS...
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College Station (CLL) 76 91 75 89 / 20 40 10 30 Houston (IAH) 77 89 75 84 / 40 70 30 70 Galveston (GLS) 80 88 80 86 / 70 80 60 80
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&& .HGX WATCHES/WARNINGS/ADVISORIES...
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TX...None. GM...Small Craft Should Exercise Caution from 7 PM CDT this evening through Monday afternoon for GMZ330-335-350-355-370-375. Small Craft Advisory from 1 PM Monday to 7 AM CDT Tuesday for GMZ330-335-350-355-370-375.
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&& $$ SHORT TERM...Cady LONG TERM....03 AVIATION...Cady MARINE...03