299 FXUS64 KBRO 232345 AAA AFDBRO Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 545 PM CST Tue Feb 23 2021 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION...VFR conditions are currently being observed at all aerodromes. Overnight MVFR conditions will develop across all aerodromes after midnight. VFR conditions will return by midday Wednesday. Winds will remain moderate overnight and become strong Wednesday afternoon with gusts up to 30 kts. && .PREV DISCUSSION... /issued 233 PM CST Tue Feb 23 2021/ SHORT TERM (Tonight through Wednesday Night): High pressure builds across the Gulf of Mexico and heads east, while weak low pressure meanders southeast across North Texas and into East Texas or Louisiana by Wednesday night. The stalled frontal boundary currently offshore lifts north as a warm front into Wednesday and the cold front associated with the North Texas low slowly approaches central to southern Texas late Wednesday night. Expect southeasterly to southerly winds to increase this afternoon and Wednesday afternoon as the pressure gradient increases, tapering off into Wednesday night. Low level moisture increases through the period as well, bringing bouts of low cloud cover at night and patchy to areas of fog, mainly late Wednesday night across the ranchlands. Sea fog may become pesky to persistent through the period at night as well, mainly along the northern bay waters. Temperatures will remain well above normal through the short term, with highs into the 80s everywhere except the coast and lows into the low to mid 60s. LONG TERM (Thursday through Monday): With an onshore flow expected to persist through much of the long term period, we can likely expect a warmer than average pattern to continue through the end of the period along with high surface moisture, and periodic PoPs which will be discussed below. A positive-tilted trough will sweep across the Great Plains Thursday, while a stationary front remains draped across Central Texas and a surface trough begins to form over Deep South Texas. This front is then expected to gain a little southward momentum and near the northern ranchlands of Deep South Texas Thursday night into Friday morning as a weak cold front. Exactly how far south this front advances remains the key question as the models continue to differ and will have a major impact on temps and PoPs on Friday. The ECM holds it back over South Texas (north of our CWA) and the NAM brings it all the way south of the Rio Grande through Friday, but for now, leaned towards a blend favoring the GFS which happens to be the middle ground between the current model outputs...bringing the front just to the northern border of our CWA before it retreats northward on Friday. With the approach of the front, we have slight chance PoPs on Thursday evening into Friday mostly concentrated along our northern border and the coastal areas. On Friday, the front will lift slowly northward as a warm front and provide a focus for convection across the Texas coast on Friday and into the weekend, with most of the action being focused in SE TX and LA. The mid level flow will become more southwesterly over Texas through the weekend and into early next week as a trough shoots south across the Pacific Coast and pinches off into a cutoff low that will then spin over the Desert Southwest region. All the while, a southeasterly surface flow will persist across Deep South Texas, continuing to bring in warm, moist air to the region. MARINE (Tonight through Wednesday Night): High pressure builds across the Gulf of Mexico as low pressure works from North Texas into East Texas, increasing southeasterly to southerly flow along the lower Texas coast through the short term period. Expect Small Craft Caution conditions Wednesday afternoon, especially across the bay and nearshore waters as the pressure gradient strengthens. Patchy fog may return at times tonight and Wednesday night across the bay and nearshore Gulf of Mexico waters, especially across the northern bay waters near Kenedy County. Thursday through Saturday...A persistent moderate southeast flow with moderate seas will be the name of the game through the end of the week and into the weekend, with no SCA conditions expected. However, there is a possibility that the front will make it further south and into the lower Texas coastal waters on Friday morning, so stay tuned for updates. There will be a slight chance of some showers along the Texas coastline Thursday night into Friday as a weak cold front approaches Deep South Texas, along with the possibility of some marine fog over the nearshore and bay waters on Thursday. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 64 76 65 77 / 0 0 10 10 BROWNSVILLE 66 81 66 80 / 0 0 10 10 HARLINGEN 64 82 65 81 / 0 0 10 10 MCALLEN 64 85 65 83 / 0 0 0 10 RIO GRANDE CITY 63 87 64 86 / 0 0 0 10 SOUTH PADRE ISLAND 66 72 66 72 / 0 0 10 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV 68-McGinnis/Aviation