FXUS64 KBRO 210422 AAA AFDBRO Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 1022 PM CST Wed Jan 20 2021 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION...Minor adjustments made to the previous suite of TAFs. Low clouds, light rain, and light fog continue to be anticipated tonight. Tomorrow, a moderate to breezy onshore flow will create higher ceilings. A slip into MVFR territory may occur Thursday evening, especially at MFE, but confidence in this is low. && .PREV DISCUSSION... /issued 532 PM CST Wed Jan 20 2021/ DISCUSSION...Updated for latest aviation discussion below. AVIATION...Less than ideal aviation conditions are expected through the overnight hours with low clouds, light rain, and light fog anticipated. Tomorrow, a re-developing and intensifying onshore flow will bring warmer air into the region, allowing ceilings to rise to VFR levels. PREV DISCUSSION... /issued 246 PM CST Wed Jan 20 2021/ SHORT TERM (Now through Thursday Night): A cold front has worked its way just west of the immediate coast and lies pretty much along I-69E. Temperatures are in the 50s to near 60 west of the front and in the 70s east of the front. Light northwest winds, patches of rain and drizzle, low clouds and some patchy fog with vsby of 2-5 miles are being observed west of the frontal boundary. Models suggest the front remaining stationary or wobbling towards the coastline by sunrise Thursday before slowly dissipating or moving north Thursday afternoon. Weak but persistent isentropic upglide overnight and Thursday morning is expected with warmer 925-850mb southerly winds overriding the cooler surface condition in response to an upper low pressure area moving into NW Mexico. Light rain, drizzle, patchy fog and steady temperatures are expected tonight and Thu morning. As southerly flow returns and increases Thursday the rain and drizzle end but plenty of clouds should linger and be slow in lifting and thinning. Limited sunshine and a delay in the south winds will likely limit maximum heating so have opted to lower temperatures below consensus keeping them in the low 70s. Benign weather continues into Thursday night with mostly cloudy skies, some patchy fog and mild temperatures in the 60s. LONG TERM (Friday through Wednesday): Whatever is left of the Baja Low ejects eastward across Texas on Friday as high pressure drops out of Central Canada and sends an associated surface front stalling into Central Texas on Saturday. As a series of 500mb shortwaves dive south along the Pacific coast, mid level ridging builds again across Texas late this weekend into next week, keeping warm southwesterly flow aloft in place through the rest of the long term. The stalling surface front lifts north as a warm front on Sunday with breezy to windy conditions along the lower Texas coast. A coastal trough of low pressure develops across Deep South Texas Sunday into Monday as a surface low out of northeastern Mexico drags the next cold front toward the coast on Monday. The coastal trough and any stalled or leftover frontal boundaries keep things somewhat unsettled into Wednesday. The chance of rain remains limited through the long term, with total QPF amounts into next week remaining below a tenth of an inch. The best chances of rain remain Saturday afternoon into Sunday, mainly near the coast, and again on Wednesday near the coast. Temperatures remain warmer than normal through the period, potentially 12 to 15 degrees above normal on Sunday. With the abundance of low level moisture, and light to calm winds, expect patchy fog again Friday morning, and potentially Saturday morning too. MARINE (Now through Thursday night): A stationary front along the lower and middle Texas coast has weakened the pressure gradient across the Western Gulf. Light southerly winds and a modest to slight sea are expected through Thursday morning. The front dissipates Thursday afternoon with high pressure building over the eastern Gulf of Mexico. The pressure gradient to gradually strengthen overnight Thursday as the ridge combines with lowering pressure over West Texas. Exercise caution conditions may be warranted over the outer offshore coastal waters after midnight Thursday. Friday through Wednesday: High pressure works east across the Gulf of Mexico through the weekend as coastal low pressure develops along the lower Texas coast into early next week. The pressure gradient strengthens on Sunday, building southerly winds and seas into Monday before a cold front brings a northerly wind shift and improving seas late Monday through Tuesday. Small Craft Advisories are likely by Sunday night through Monday afternoon and may be needed across the bay Sunday afternoon due to winds. Patchy fog is possible Friday morning, and potentially Saturday morning as well, across the Laguna Madre and coastal Gulf waters. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 65 73 63 77 / 20 20 10 20 BROWNSVILLE 65 75 67 80 / 30 20 10 20 HARLINGEN 60 73 64 80 / 30 20 10 10 MCALLEN 59 74 64 81 / 20 20 0 10 RIO GRANDE CITY 55 74 61 83 / 20 10 10 0 SOUTH PADRE ISLAND 67 70 68 72 / 20 20 10 20 && .BRO WATCHES/WARNINGS/ADVISORIES...None. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV