Sunrise 6:48 AM   Sunset 7:54 PM Moonrise 4:13 PM   Moonset 4:10 AM

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GMZ335 Galveston Bay- 242 Am Cdt Sat Apr 20 2024
Today - East winds around 10 knots, becoming southeast 10 to 15 knots this afternoon. Bay waters slightly choppy. Patchy fog early this morning. A chance of showers and Thunderstorms. Tonight - East winds 10 to 15 knots, becoming northeast after midnight. Bay waters slightly choppy. Showers and Thunderstorms likely. Sunday - North winds 15 to 20 knots. Bay waters choppy. A chance of showers and Thunderstorms. Sunday night - Northeast winds 15 to 20 knots, diminishing to around 15 knots late. Bay waters choppy, becoming slightly choppy late. Monday - Northeast winds 15 to 20 knots, becoming east around 15 knots in the afternoon. Bay waters choppy, becoming slightly choppy in the afternoon. Monday night - Southeast winds 5 to 10 knots. Bay waters smooth.Tuesday - Southeast winds 5 to 10 knots. Bay waters smooth. Tuesday night - Southeast winds 5 to 10 knots. Bay waters smooth. Wednesday - Southeast winds around 10 knots, increasing to 10 to 15 knots in the afternoon. Bay waters smooth, becoming slightly choppy in the afternoon. Wednesday night - Southeast winds 10 to 15 knots. Bay waters slightly choppy.

GMZ300 Synopsis For High Island To The Matagorda Ship Channel Out 60 Nautical Miles Including Galveston And Matagorda Bays 242 Am Cdt Sat Apr 20 2024
Synopsis for high island to the matagorda ship channel out 60 nm including galveston and matagorda bays
onshore winds will prevail through tomorrow night, resulting in some patchy fog development through tomorrow morning. A cold front will move offshore tomorrow night, resulting in a shift to moderate northeast winds. Showers and Thunderstorms will develop along and ahead of the front, impacting the bays and coastal waters between later tomorrow afternoon and Sunday morning. As the front departs, moderate to strong offshore winds will develop which will likely require a small craft advisory. Winds will relax by Monday, with onshore flow redeveloping on Tuesday.

FXUS64 KHGX 200450 AFDHGX

Area Forecast Discussion National Weather Service Houston/Galveston TX 1150 PM CDT Fri Apr 19 2024

New AVIATION

SHORT TERM
(This evening through Saturday Night)
Issued at 233 PM CDT Fri Apr 19 2024

A LL boundary is currently draped across the region, extending west to east from Colorado County to Liberty County. Scattered shower activity has developed along the boundary this afternoon.
The boundary and its associated rain showers should drift northward as the afternoon progresses into the evening. Also monitoring some northward progressing showers offshore. Generally speaking, any rainfall activity is expected to be isolated to widely scattered. Couldn't rule out an isolated thunderstorm.
Temperatures are mostly in the low 80s under mostly cloudy skies with humid conditions. Temps may warm a couple more degrees before sunset yields to another cloudy muggy night in the low 70s.
Areas north of the boundary are expected to fall into the 60s.

While we enjoy this humid afternoon with a rain shower here and there, a broad mid/upper trough with a leading mid/level southwesterly jet streak is pushing eastward across SW CONUS. By tomorrow, and especially tomorrow night, this feature will provide various synoptic mid/upper forcings that will support widespread showers and thunderstorms. The UL flow at 300-250mb will become increasingly diffluent while mid/upper west-southwesterly shear gradually increases in the 700-500mb layer. This shear orientation will be roughly parallel to the aforementioned boundary, which will be stalled near our northern counties as we begin our Saturday. Eventually, building sfc high pressure from the north will push the boundary southward. Deep LL convergence (sfc-850mb)
associated with the boundary is apparent in the guidance. Global and HRRR ensemble means indicate a high chance of widespread 1.70-1.90" PWAT values with some potential of exceeding 2.00".

So what do the these parameters mean for our Saturday? Though the primary shower/thunderstorm concern is for Saturday evening/night, a series of vort maxes embedded in the flow aloft could foment scattered shower and thunderstorm activity as early as Saturday afternoon, especially north of I-10. HRRR members also suggest we shouldn't rule out isolated to widely scattered showers in the morning. PWs, UL diffulence, mid/upper shear, and PVA all begin to approach their peak late afternoon and into the evening hours on Saturday. This is when heavier showers/storms are more likely to be supported, especially near the boundary. Now here is where things get tricky. Where will this boundary be? How fast it will push southward? Will it stall? There is high confidence that the mid/upper levels will support plentiful ascent for widespread showers/thunderstorms. There is high confidence in favorable conditions for heavy rainfall. But there is less confidence in the exact position of the LL boundary when these other parameters line up. This has significant implications on where the heaviest rainfall occurs. The best chance of heavy rainfall (where locally several inches of rainfall could occur over a short period of time) continues to be north of I-10. Widespread totals north of I-10 are still forecast to be in the 1-3 inch range. But locally much heavier totals are likely in locations that receive the heaviest showers and thunderstorms late Saturday afternoon into the overnight. The Weather Prediction Center has issued a slight (level 2 of 4) risk of excessive rainfall north of I-10. Farther south, the risk is marginal (level 1 of 4).

Self

LONG TERM
(Sunday through next Thursday)
Issued at 233 PM CDT Fri Apr 19 2024

Rain should be coming to an end Sunday morning as this system pushes out of here and the front makes further southward progress off the coast. Cooler, drier air will be filtering in, though clouds might hang around for a good part of the day before scattering out Sunday night.

Surface high pressure will begin moving off to the east Monday, though we'll still probably see some recycled drier air backdoor into parts the region at times. It probably won't be until midweek when we see more noticeable dewpoint modifications and warming overnight lows.

A prevailing onshore flow will be the rule during the second half of the workweek into the weekend. Slight chances of mainly diurnally driven shra and/or tstms are a possibility, though some subtle mid- upper ridging will be a limiting factor. 47

AVIATION
(06Z TAF Issuance)
Issued at 1147 PM CDT Fri Apr 19 2024

Mix of VFR/MVFR expected to become MVFR/IFR during the overnight hours. LBX already at IFR with CIGs . Expect -RA and VCTS around 19-22Z for northern terminals, moving SE during the day. Showers and thunderstorms expected to continue Saturday afternoon into the overnight hours with lingering showers Sunday morning. Some showers and storms could produce locally heavy rainfall and decreased VSBYs. Expect CIGs to remain at widespread MVFR/IFR levels overnight through the end of the period.

MARINE
Issued at 233 PM CDT Fri Apr 19 2024

Onshore flow will persist into Saturday. Periods of haze and fog can be anticipated but it is not expected to become dense. The next cold front and associated showers and thunderstorms will push off the coast late Saturday night followed by moderate north and northeast winds and building seas in its wake. Small Craft Advisories will likely be required. As high pressure begin moving east of the region on Monday, onshore winds will resume. As the pressure gradient tightens Wed-Fri, look for a fetch of moderate southeast winds to set up across the Gulf during the second half of the week. 47

HYDROLOGY
Issued at 333 PM CDT Fri Apr 19 2024

Conditions are favorable for some locally heavy rain Saturday evening an overnight. Though there is some uncertainty exactly where it will fall, latest guidance tends to favor locations north of I-10.
Several inches of rain in a short time period will runoff and could pose a flash flood threat. Residents north of I-10 should be on the lookout for rises on area creeks, streams and rivers. Contingency forecasts highlight the potential for minor river flooding.
Additional impacts are possible for smaller tributaries. Lastly, area reservoirs are full, so any runoff will need to be released.
Pay attention to updated forecasts. 47/KLG

PRELIMINARY POINT TEMPS/POPS
College Station (CLL) 67 75 53 63 / 20 80 90 0 Houston (IAH) 71 81 58 66 / 20 60 80 20 Galveston (GLS) 71 77 61 70 / 10 20 80 30

HGX WATCHES/WARNINGS/ADVISORIES
TX...None.
GM...None.

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Lynchburg Landing
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Sat -- 02:49 AM CDT     0.65 feet Low Tide
Sat -- 05:08 AM CDT     Moonset
Sat -- 06:47 AM CDT     Sunrise
Sat -- 08:51 AM CDT     0.95 feet High Tide
Sat -- 03:01 PM CDT     0.64 feet Low Tide
Sat -- 05:10 PM CDT     Moonrise
Sat -- 07:50 PM CDT     Sunset
Sat -- 08:28 PM CDT     0.91 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Lynchburg Landing, San Jacinto River, Texas, Tide feet

Clear Lake
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Sat -- 03:36 AM CDT     0.32 feet Low Tide
Sat -- 05:08 AM CDT     Moonset
Sat -- 06:47 AM CDT     Sunrise
Sat -- 08:59 AM CDT     0.64 feet High Tide
Sat -- 03:58 PM CDT     0.19 feet Low Tide
Sat -- 05:10 PM CDT     Moonrise
Sat -- 07:50 PM CDT     Sunset
Sat -- 09:32 PM CDT     0.57 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Clear Lake, Harris Co. Park, Texas, Tide feet

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