Area Forecast Discussion
Issued by NWS Brownsville, TX

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000 FXUS64 KBRO 062329 AAA AFDBRO Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 529 PM CST Sat Mar 6 2021 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION...VFR conditions are expected to generally prevail through the TAF period. Dry northeasterly flow turns more easterly into Sunday, with increasing cloud cover. At this time, do not expect much of any fog across the RGV, but patchy fog may develop along the coast and work inland toward BRO by early morning. && .PREV DISCUSSION... /issued 222 PM CST Sat Mar 6 2021/ SHORT TERM (Now through Sunday Night): Weak 500mb ridging will make its way over the region this evening, favoring continued subsidence and clearing skies this evening. This will be quickly followed by the approach of a weak 500mb shortwave as well as surface winds shifting to onshore flow. This will favor some fairly persistent cloud cover through the remainder of the short term. Temperatures on Sunday arent expected to rebound quite as quickly as today owing to lower level cloud cover hanging around for most of Sunday. The same 500mb shortwave may also help ignite some shower activity later Sunday afternoon and evening, but the lack of deep layer moisture suggests isolated activity at best so will leave any mentionable chances for precipitation out of the forecast. Onshore flow then looks to persist through Sunday night, with the associated moisture return and eventual calming winds possibly contributing to some patchy fog developing overnight Sunday into Monday. LONG TERM (Monday through Saturday):12Z model suite in good agreement and consistency through much of next work week with some discrepancy showing up for next weekend. In the meantime...the battle of the season`s will be the theme next week as a large cold upper trough and low pressure center settle over the Western third of the U.S. while the subtropical ridge builds over Northern Mexico and the Western Gulf of Mexico. The outlook for Deep S Texas and the RGV for next week sums up to be a very warm, dry and breezy to windy period. The building of the subtropical ridge steadily increases heights and thicknesses which will support temperatures climbing well into the 80s and some 90s for the mid and upper Valleys the latter half of the week. The building ridge caps the atmosphere with a very shallow airmass in place not enough to warrant any significant rain chances at this time. A series of surface low pressure areas are expected to develop and eject out into the Plains States, courtesy of the Upper trough/low, which will combine with broad surface ridge over the Gulf South to the Mid-Atlantic producing a steadily strengthening pressure gradient. The South Texas wind machine will be in full swing Tuesday through Friday with the strongest gradient anticipated along the coastal counties spreading inland through the Mid-Valley locations. As the previous forecast mentioned Wind Advisories are likely to be issued with best days next Wed-Friday. As the period moves into next weekend GFS is aggressive with a frontal passage as it shows the Western U.S. trough moving east. The ECMWF is somewhat delayed in ejecting the upper trough eastward keeping the RGV warm, breezy and dry. Consensus takes the ECMWF route keeping any fronts well north of Deep South Texas. With an anticipated extended period of a large fetch of east to southeasterly winds developing across the northern Gulf of Mexico, the lower Texas coast may be impacted by slightly elevated swells, likely increasing the risk of rip currents and possibly some minor overwash of tidal action. Even though the weather should be pleasant at the beach next week, beach-goers should pay attention to the flags and signs at the beach and be very cautious if entering the surf. MARINE:(Now through Sunday Night): Gusty northerly winds continue across much of the coastal waters this afternoon with the Small Craft Advisory running through 3 PM for the Laguna Madre and 6 PM for the Gulf Waters. Some Small Craft Exercise Caution conditions will persist through the evening hours as winds gradually relax and seas subsequently fall. Seas will then remain elevated through the end of the short term as winds shift and create an easterly fetch, favoring persistent easterly swell. (Monday through Thursday)...Mariners can expect to see a strengthening of the pressure gradient over the Western Gulf and along the lower Texas coast next week with a steady increase in winds and build up in total seas. Large expansive surface high pressure spreads over the Gulf South and Mid-Atlantic States extending well into the Northern Gulf of Mexico. The ridge is expected to combine with a series of low pressure areas that will be developing over the leeside of the Rockies and track into the Plains States. At this time the strongest gradient is expected Wednesday through next Friday with Small Craft Advisories likely for portions or all of the lower Texas coastal waters. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 56 70 58 72 / 0 10 0 0 BROWNSVILLE 55 73 59 74 / 0 10 10 0 HARLINGEN 52 73 56 75 / 0 10 0 0 MCALLEN 51 74 56 76 / 0 10 0 0 RIO GRANDE CITY 49 75 56 79 / 0 10 0 0 SOUTH PADRE ISLAND 59 66 61 67 / 0 10 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV 56-Hallman...Aviation is the U.S. government's official web portal to all federal, state and local government web resources and services.