Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
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033 FXUS64 KBRO 200524 AAA AFDBRO Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 1224 AM CDT Mon May 20 2024 ...New AVIATION... .SHORT TERM... (Tonight through Monday night) Issued at 148 PM CDT Sun May 19 2024 The main weather story will continue to be the building heat through the short-term period and beyond. This is due to a mid/upper level ridge axis anchored across Mexico expanding into Texas and the remainder of the Southern Plains over the next few days. Strong subsidence and limited moisture depth will keep a rain-free forecast going. It does appear that we will have one more day on Monday where heat advisory criteria (111 degree heat indices) will be just shy of being met for most of the area. A few isolated locations will likely reach 111 heat index or just exceed it for an hour or two but not long enough or widespread enough to warrant a heat advisory at this time for Monday. Heat indices will generally peak between 105 and 110 degrees on Monday. Geocolor satellite imagery continues to depict the core of the agricultural smoke/haze over the open Gulf with the periphery of this affecting portions of our CWA. Based upon the RAP-Smoke and GEOS-5 models forecast of vertically integrated smoke and total aerosols, have decided to add haze to the weather grids through Monday. && .LONG TERM... (Tuesday through next Sunday) Issued at 148 PM CDT Sun May 19 2024 Key Messages: - Above normal temperatures and heat index values are expected across Deep South Texas this week and Memorial Day weekend. - The combination of above normal temperatures and humidity will yield dangerous heat index values in the 110-120 degree range during the day, and in the upper 80s to low 90s overnight. - There will be an increased risk of heat related impacts, especially those that do not take adequate breaks in the shade or stay hydrated. - Poor air quality will continue through the week for most of the region. Mid/upper level ridging centered over Mexico will maintain rain-free conditions and above normal temperatures across Deep South Texas into Memorial Day weekend. Meanwhile, persistent low level southerly to southeasterly flow will result in continued humid conditions at the surface. In addition to the heat and humidity, low level winds will continue to transport smoke associated with agricultural burning in southeast Mexico, which will maintain poor air quality across portions of the region. A steady increase in temperatures is expected through the week and into the weekend as the ridge continues to build, with afternoon high temperatures ranging from the mid to upper 80s along the Lower Texas beaches, mid to upper 90s along/east of I-69, and above 100 degrees (100-106 degrees) west of I-69. In combination with the humidity, "feels like" temperatures will range from upper 90s along the Lower Texas beaches to around 112 degrees through Thursday, and closer to 114-118 degrees Friday through the weekend, across the Northern Ranchlands and Rio Grande Valley. In comparison to the early May heat wave, one notable difference is the forecast of higher minimum temperatures each night... with most of the Rio Grande Valley expected to observe low temperatures in the low 80s. In combination with the high dew points in place, there won`t be much relief from the heat overnight as "feels like" temperatures remain in the upper 80s and low to mid 90s. This will result in a major to extreme risk of heat-related impacts, especially towards the end of the week and into the weekend. Staying properly hydrated, limiting time spent outdoors during the peak heating of the day, taking frequent breaks in the shade, and wearing light-colored, loose-fitting clothing will be necessary to prevent any heat related illnesses. Heat headlines may be needed for portions of the region Wednesday and Thursday, and will likely be needed this Memorial Day weekend. Regardless of the issuance of any heat products (Heat Advisory, Excessive Heat Warning), the prolonged period of oppressive daytime and nighttime temperatures will limit the ability to recover from the heat, especially if spending several hours outside during the day. If you have any outdoor plans this weekend for Memorial Day or attending outdoor graduation ceremonies, make sure you are taking the oppressive heat into account. && .AVIATION... (06Z TAFS) Issued at 1223 AM CDT Mon May 20 2024 MVFR to VFR will continue to be the rule at the aerodromes through the next 24 hours. && .MARINE... Issued at 148 PM CDT Sun May 19 2024 Tonight through Monday night...Generally weak onshore flow will continue tonight. However 3-4 ft swells will persist but are expected to slowly decay through the short-term. Overall, this will tend to maintain a moderate risk of rip currents through tonight with a borderline moderate risk of rips on Monday. The flow will continue to veer through Monday as a more climatologically normal return flow setup establishes itself. A bit more in the way of a moderate onshore flow as a result will establish itself by Monday afternoon and continue through Tuesday morning. Seas will slowly respond and build back to 4 ft overnight on Monday. Tuesday through Saturday...Light to moderate winds and moderate seas are expected through the weekend. A locally enhanced pressure gradient may result in a brief period of Small Craft Exercise Caution conditions each afternoon on the Laguna Madre and nearshore Gulf waters. Small Craft Exercise Caution conditions will extend to the offshore Gulf waters Thursday and Friday due to increased winds and seas slightly building. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 95 80 94 81 / 0 0 0 0 HARLINGEN 97 77 97 79 / 0 0 0 0 MCALLEN 100 79 99 80 / 0 0 0 0 RIO GRANDE CITY 100 77 101 79 / 0 0 0 0 SOUTH PADRE ISLAND 86 81 86 81 / 0 0 0 0 BAYVIEW/PORT ISABEL 92 79 92 80 / 0 0 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES...None. && $$