378 FXUS64 KBRO 192317 AAA AFDBRO Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 617 PM CDT Tue Oct 19 2021 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION...VFR conditions will continue to prevail over all aerodromes through the TAF period. Winds will continue to decrease overnight becoming light to near calm and variable after midnight. Southeasterly winds will then increase after daybreak on Tuesday with light to moderate winds. && .PREV DISCUSSION... /issued 244 PM CDT Tue Oct 19 2021/ SHORT TERM (Now through Wednesday Night): October 2021 has leaned warmer than average, despite two modest fronts that pushed readings into the comfort zone between the 6th and 9th (mainly lower humidity and pleasant overnights) and this past weekend through Monday. That 'lean' continues for the foreseeable future, beginning today and continuing through the week, as 90+ degree temperatures return for most and humidity creeps up...though initially nothing like the swelter that was featured last week when morning lows only fell to near 80 for much of the populated Rio Grande Valley. Through Wednesday night...the main feature aloft is a flat 500 mb ridge that lifts a bit farther north to cover all of south Texas. With no short wave energy embedded within the ridge, little more than mixed fair weather cumulus and occasional passing cirrus can be expected, with generally light southeast flow freshening up a touch each afternoon with sea breeze enhancement. By Wednesday night, models diverge just a smidge with the newly-arrived ECMWF showing a bit more strength to a bubble surface high nosing south from east Texas, which would bring near calm winds in all areas but no perceptible change to sensible weather. In terms of sensible weather...will lower minimum temperatures a touch each night due to the light winds and mainly clear skies, as well as values early this morning which were several degrees lower than blended guidance in several spots. Will tweak Wednesday's highs just a touch for the same reason. For all areas, values will be near seasonal averages at night (65-71) but a few degrees above them by day (lower 90s vs. upper 80s). LONG TERM (Thursday through Tuesday): Overall, the long term is looking rather warm and dry, except for some slight chance PoPs for portions of Deep South Texas this weekend. Mid level flow will start off quasi-zonal before a very weak shortwave slowly moves across the region this weekend. With an onshore flow at the surface continuing to keep low level moisture elevated through the weekend, have kept some slight chance PoPs for mostly the coastal areas Friday through Sunday. Early next week a deep longwave trough will dive into the western CONUS and help to amplify the ridge over the northern Gulf of Mexico. Surface winds will increase slightly across Deep South Texas and become more south-southeasterly with high pressure to our east and a series of lows forming on the lee-side of the Rockies. Some PVA associated with a potential tropical system off the Pacific coast of Mexico may rotate through the top of the mid level ridge to maintain a slight chance of PoPs through early next week, but confidence is a bit lower on that solution, so have opted to keep rain chances out of the picture (except along the immediate coast) for that period for now. Temperatures will gradually warm through the period. Afternoon highs may only be a few degrees above seasonal normal, but overnight lows will be about 5-10 degrees above normal by early next week. MARINE: Now through Wednesday Night...Continued light southeast flow through the period...generally 10 knots or less except 10 to 15 knots along Laguna Madre during the afternoon/early evening as broad ridge extends from the southeast U.S. to the Texas coast. As mentioned above, ECMWF suggests total collapse of marine winds along the coast by early Thursday with GFS keeps light southeast flow...so will maintain a light easterly blend to cover. A minor issue given generally slight seas and fair weather. Bottom line? Ideal boating and fishing conditions for those headed out. Thursday through Sunday...Marine conditions will be fairly benign with low to moderate seas and moderate southeasterly winds. However, small craft may need to exercise caution for brief periods of time this weekend as winds increase above 15 knots with a moderate pressure gradient. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 70 87 70 87 / 0 0 0 10 BROWNSVILLE 69 89 70 90 / 0 10 0 10 HARLINGEN 67 90 68 89 / 0 0 0 10 MCALLEN 69 92 70 92 / 0 0 0 10 RIO GRANDE CITY 69 93 68 94 / 0 0 0 0 SOUTH PADRE ISLAND 77 83 78 83 / 0 10 0 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ This product is also available on the web at: https://weather.gov/rgv 68-McGinnis/Aviation