Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
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925 FXUS64 KBRO 130748 AFDBRO Area Forecast Discussion National Weather Service Brownsville TX 248 AM CDT Thu Jun 13 2024 ...New SHORT TERM, LONG TERM, MARINE... .SHORT TERM... (Today through Friday) Issued at 246 AM CDT Thu Jun 13 2024 The greatest extent for isolated showers and thunderstorms is anticipated for today, as precipitable water values around 2 inches combines with 500 mb high pressure that will remain centered over southern New Mexico. Indeed, HRRR guidance suggests pockets of isolated convection moving north-northeast to south- southwest across Deep South Texas and the Rio Grande Valley, especially during the late afternoon hours. On Friday, the center of the mid-level high will move into Oklahoma, while precipitable water values fall to around 1.5 inches. The result will be an even lesser chance for showers and thunderstorms, with the greatest likelihood of them progged to be generally along and east of the Interstate 69E corridor. Temperature-wise, even with 500 mb high pressure becoming more of a factor during the period, above normal temperatures are forecast, and not well above normal. This will result in a HEAT ADVISORY not likely for today and Friday, so will instead manage the heat indices with a SPECIAL WEATHER STATEMENT on both of those days. && .LONG TERM... (Friday night through Wednesday) Issued at 246 AM CDT Thu Jun 13 2024 Most of the same train of thought continues to carry over with this forecast package for the long term forecast. The two big stories to really talk about happen to be very connected with one another. The first of which is the potential for rainfall as an inverted trough moves westward over the Gulf of Mexico during the early part of the work week, and the second is the potential development of a tropical cyclone during the early work week in the Bay of Campeche. Starting with the rain chances for Deep South Texas and the Rio Grande Valley, there are some isolated showers and thunderstorms that try to get going on Saturday with the diurnal sea breeze. However that rain chances are expected to be more limited to the Lower Rio Grande Valley on that day. Rain chances start to pick up more on Sunday, as the middle and upper levels of the atmosphere become more moist allowing for a more favorable environment for the development of showers and thunderstorms. However rain chances are still only isolated on Sunday. Starting on Monday, the rain chances will increase further and further each day through Wednesday based on the latest model guidance. With rain chances getting up to around 60 percent by Wednesday and all of Deep South Texas and the Rio Grande Valley having some form of rainfall potential, there is a very good chance of getting much needed rainfall. However, there is an interesting twist to the potential for rainfall that is tied to the potential development of a tropical cyclone down in the Bay of Campeche. While the environment is certainly favorable for a Tropical Depression or a weak Tropical Storm to develop. The synoptic flow patterns would steer the center of this system to making landfall somewhere around Tampico and Veracruz. At this current time, the National Hurricane Center has increased the chances of formation to 40 percent, and further increases likely to occur based on the current model guidance. Something to watch for in further forecast shifts is that if this system becomes stronger, the potential for rain for Deep South Texas and the Rio Grande Valley will actually start to decrease as more of the tropical moisture is pulled closer to the storm and the heavier rainbands will remain to the south of the region. However, since this tropical cyclone has yet to develop, current thought process is to go with a more widespread rainfall scenario. The much needed rainfall is not the only impacts that will be felt over the course of the long term forecast period. Because of the enhanced pressure gradient a stronger easterly to southeasterly flow will develop that will generate bigger swell that will in turn lead to a higher risk of rip currents along the beaches and even some coastal flooding concerns as well during the early part of the work week. As for the temperatures for the long term forecast period, the highs will start off in the range of upper 90s for most of Deep South Texas and the Rio Grande Valley, with a few areas in the triple digits, but will decrease over the period to being mostly in the 90s thanks to all the cloud coverage that is expected to move in. Heat indices are expected to be in the range of 105-110 thus staying out of Heat Advisory criteria, but could still warrant a Special Weather Statement. The low temperatures on the other hand, will be mostly in the 70s, but a few places could toe into the low 80s at times. && .AVIATION... (06Z TAFS) Issued at 1200 AM CDT Thu Jun 13 2024 VFR will prevail at the aerodromes through the next 24 hours. && .MARINE... Issued at 246 AM CDT Thu Jun 13 2024 Today through Friday...Surface high pressure centered generally over Louisiana will continue to be the dominant weather influence over the western Gulf of Mexico through the period. Light to moderate winds and low to moderate seas are anticipated along the Lower Texas Coast, with neither Small Craft Should Exercise Caution nor Small Craft Advisory likely to be needed. Friday Night through Wednesday...Mostly favorable conditions for the weekend as light to moderate easterly winds with low seas are expected with some showers and thunderstorms possible. However, as an inverted trough moves across the Gulf of Mexico, there is the potential for the development of a tropical cyclone during the early part of the work week. The enhanced swells that will be generated by this system will likely result in adverse and hazardous conditions that will require Small Craft Advisories through Wednesday. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 96 79 95 79 / 20 10 30 10 HARLINGEN 97 75 96 75 / 30 0 20 10 MCALLEN 99 79 99 78 / 20 0 10 0 RIO GRANDE CITY 99 78 99 76 / 10 0 0 0 SOUTH PADRE ISLAND 88 82 88 82 / 30 10 30 10 BAYVIEW/PORT ISABEL 93 79 92 79 / 20 10 30 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...66-Tomaselli LONG TERM....64-Katz AVIATION...66-Tomaselli