Marine Weather and Tide Forecast for Port Mansfield, TX

LONG TERM
(Thursday night through Tuesday)
Issued at 303 AM CDT Wed Apr 30 2025

The passage of upper-level disturbances over Deep South Texas and the Rio Grande Valley are expected to persist through the duration of the long term forecast period. This will see a low chance (around 20-30%) of rain for Friday. However by Friday night, those chances of rain are expected to increase to a medium chance (around 70%)
late Friday night into Saturday morning. This will be the result of a frontal boundary moving into the region. This front is expected to stall out over the region, which will provide a hospitable region for the development of showers and thunderstorms.

Current DESI probabilities have around 60% chance of rainfall totals greater than 2 inches and around 40% chance of rainfall totals greater than 4 inches for this weekend. However, this far out focusing on specific parts for the CWA is not the best idea at this point as the models could shift still. Current storm total QPF at this point shows a range of 0.75 to 1.62 inches at this point. While the current storm total QPF is not lined up exactly with the DESI probabilities, looking at the PWAT values, both the GFS and the ECMWF models do show that the environment will be very moist. It is worth pointing out at this point the GFS has PWAT values around 1.9 inches while the ECMWF model has PWAT values around 1.75 inches. Both of these values are above the 90 percentile value for this time of year, which is normally around 1.71 inches for PWATs. However they are both still below the max of 2.02 inches. Still these PWAT values indicate a very moist environment. With the stalled out frontal boundary in place over the region, then there will be a source of forcing for the low-level moisture to turn into showers and thunderstorms. These showers and thunderstorms are also capable of producing heavy rainfall at times as well. Some localized street flooding and other nuisance flooding is possible with these storms.

The front is currently expected to start to lift out of the region sometime Sunday into Monday, which will result in rain chances decreasing greatly by Monday. With rain chances around 20% for the rest of the period.

As for the temperatures for the long term forecast period, the low temperatures are generally expected to be in the range of the upper 60s to low 70s for the region. The high temperatures for Friday are expected to be mostly in the 90s for the region except for along the coast where the highs are expected to be in the upper 80s. From Saturday through Tuesday, the high temperatures are generally expected to be in the 80s.

AVIATION
(12Z TAFS)
Issued at 618 AM CDT Wed Apr 30 2025

Breezy to windy conditions will prevail through a majority of the period with mostly cloudy skies and no precipitation. MVFR to VFR will prevail through the TAF period.

MARINE
Issued at 303 AM CDT Wed Apr 30 2025

Today through Thursday...Buoy 42020 reported south-southeast winds around 21 knots gusting to around 27 knots with seas slightly over 5.5 feet with a period of 6 seconds at 1:50 CDT/6:50 UTC. A Small Craft Advisory will be in effect for the Laguna Madre and Gulf of America waters from 0 to 60 nautical miles offshore today due to an enhanced pressure gradient. The Advisory may need to be extended through tonight, but a weakening of the gradient on Thursday should allow for more moderate winds and seas, with a Small Craft Should Exercise Caution not entirely ruled out.

Thursday Night through Tuesday...The start of the period will see mostly light to moderate onshore winds and low to moderate seas. By Sunday the winds are expected to shift more towards the east and increase to more adverse conditions requiring Small Craft Exercise Caution for the Gulf waters and remain that way for the rest of the period.

PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 88 76 88 75 / 0 0 10 10 HARLINGEN 91 73 91 72 / 0 0 10 10 MCALLEN 94 76 94 75 / 10 10 10 20 RIO GRANDE CITY 97 74 95 73 / 10 10 20 20 SOUTH PADRE ISLAND 82 75 81 75 / 0 0 0 10 BAYVIEW/PORT ISABEL 87 74 87 74 / 0 0 0 10

BRO WATCHES/WARNINGS/ADVISORIES
TX...High Rip Current Risk through Thursday evening for TXZ451-454- 455.

GM...Small Craft Advisory until 4 PM CDT this afternoon for GMZ130- 132-135.

Small Craft Advisory until 7 PM CDT this evening for GMZ150-155- 170-175.