Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
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947 FXUS64 KBRO 242015 AFDBRO Area Forecast Discussion National Weather Service Brownsville TX 315 PM CDT Fri May 24 2024 ...New SHORT TERM, LONG TERM, MARINE, CLIMATE... .SHORT TERM... (Tonight through Saturday night) Issued at 315 PM CDT Fri May 24 2024 Key Messages: * Excessive, Dangerous, Record-Breaking Heat Likely on Saturday * Triple digit highs likely for Brownsville, Harlingen, and McAllen on Saturday * Heat Indices between 110-120F is likely on Saturday * High Risk for Rip Currents to continue through Saturday With the local forecast area on the northern edge of a persistent 591 dam sub-tropical heat dome, this dangerous heat episode is expected to continue through the short term forecast period. Another abnormally warm and muggy night for late May is expected with overnight low temperatures holding in the lower 80s. A relatively tight pressure gradient over the area will result in breezy conditions/onshore flow continuing through tonight between 10-20 mph. Triple digit heating is likely on Saturday across almost all of Deep South Texas (outside of the coast areas) as global deterministic forecast models are suggesting H850 temps ranging between 21-27C, which is 2-3 standard deviations above normal for late May standards. This will translate to daytime highs on Saturday between 100-105F for almost all of Deep South Texas and the Rio Grandee Valley including Brownsville, Harlingen, and McAllen. Couple this with dewpoint values in the mid 70s to near 80F and we`re going to have heat indices (Real Feel Temperatures) ranging between 110-120F degrees. An Excessive Heat Warning will likely be issued later this afternoon/evening for Saturday for much of Deep South Texas. A Heat Advisory will likely be issued for much of Deep South Texas for tonight due to overnight low temperatures expected to be in the lower 80s. Saturday night will feature another abnormally warm and muggy night with overnight lows in the lower 80s and dewpoints in the mid 70s to near 80F. Breezy conditions could continue with a relatively tight pressure gradient inn place yielding in a continuation of onshore/southeast winds 10-20 mph. With these level temperatures expected for Saturday, record daytime highs are likely to be broken over Brownsville, Harlingen, and McAllen (see Climate section below for more details). Record high minimum temperatures for tonight and Saturday night could be in jeopardy as well (see Climate section below for more details). && .LONG TERM... (Sunday through next Friday) Issued at 315 PM CDT Fri May 24 2024 Key Messages: - Dangerous heat will continue through at least Tuesday, including Memorial Day. - There will be an extreme risk of heat-related impacts, especially for those that do not stay hydrated or take frequent breaks in the shade/indoors. - Moderate to high risk of rip currents will exist through Memorial Day. Triple-digit temperatures and heat indices will persist through early next week across Deep South Texas as mid/upper level ridging centered over Mexico prevails. Meanwhile, well established low level southerly to southeasterly flow will maintain elevated dew points. High temperatures will likely reach 100-104 degrees along the I-69 corridor to around 110 degrees across the Rio Grande Plains on Sunday and Memorial Day. Heat indices will range from 112 to 122 degrees across the region each afternoon as dew points remain elevated. Along the Lower Texas beaches and coastal portions of Cameron, Willacy, and Kenedy counties, high temperatures will range from the upper 80s to upper 90s. However, in combination with the high humidity, "feels like" temperatures will be over 100 degrees... including South Padre Island. Daily record high temperatures will likely be tied or broken through Memorial Day. There will be little to no relief overnight as low temperatures only fall to around 79 degrees across the Northern Ranchlands to the low to mid 80s across the Rio Grande Valley. Daily record highest low temperatures will continue to be broken each morning through at least Tuesday morning. Morning heat index values in the low 80s to mid 90s each day will make for unseasonably hot mornings for those attending any early morning outdoor events this weekend. All in all, the very warm nights and dangerously hot days will cause heat illnesses for anyone who is not acclimated to the heat or does not take proper precautions against the heat. The NWS HeatRisk tool indicates an extreme risk of heat-related impacts to those spending any time outdoors. Fortunately, there looks to be some relief from the oppressive heat next week. The mid/upper level ridge looks to weaken slightly, which will allow for the passage of weak embedded shortwaves. Slightly lower high temperatures and more seasonable heat indices are expected Tuesday through Friday. While the hope is to receive some much needed rainfall, if anything cloud cover will help with the afternoon heat. The best chances for any rain look to be Monday and Tuesday afternoon/evening, should any convection develop off the Sierra Madre. && .AVIATION... (18Z TAFS) Issued at 1226 PM CDT Fri May 24 2024 Through 18z Saturday....As of this update, VFR-MVFR conditions (mainly due to haze restricting visibilities between 3-6 miles) were taking place at the TAF sites under sunny to mostly sunny skies. VFR ceilings with some MVFR visibilities should continue through the rest of the afternoon and into the evening hours. As we shift into tonight, MVFR ceilings are expected to develop again over the area. During the day on Saturday, ceilings/sky conditions could improve/return back to VFR levels. However, MVFR visibilities (due to haze) looks to be an issue through the 18z TAF period, regardless of the ceilings. Southeast winds 10-20 kts look to continue through the 18z TAF period. Winds are expected to gust between 20-30 kts during the day. At night, wind gusts are expected to subside, however, it will still remain breezy at times with sustained winds between 10-15 kts. && .MARINE... Issued at 315 PM CDT Fri May 24 2024 Tonight through Saturday night...A High Risk for Rip Currents will continue for the area beaches along the Lower Texas Coast till 7 PM CDT on Saturday. Moderate winds via a relatively tight pressure gradient will result in SCEC conditions during the day on Saturday. Sunday through next Friday...Moderate winds and moderate seas will prevail through the period. Small Craft Exercise Caution conditions will continue through next week along the Laguna Madre and Gulf waters due to an enhanced pressure gradient. A brief Small Craft Advisory cannot be ruled out during the afternoon hours as wind speeds increase. && .CLIMATE... Issued at 315 PM CDT Fri May 24 2024 Record High Minimums for tonight Brownsville 81F in 2019 Harlingen 80F in 2016 McAllen 79F in 2019 Record Daytime Highs for Saturday May 25, 2024 Brownsville 97F in 2018 Harlingen 97F in 2018 McAllen 103F in 1989 && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 82 101 83 100 / 0 0 0 0 HARLINGEN 80 102 80 100 / 0 0 0 0 MCALLEN 82 104 81 105 / 0 0 0 0 RIO GRANDE CITY 80 105 80 107 / 0 0 0 0 SOUTH PADRE ISLAND 83 88 83 88 / 0 0 0 0 BAYVIEW/PORT ISABEL 80 95 81 95 / 0 0 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...Excessive Heat Warning until 7 PM CDT this evening for TXZ248>253-353. Heat Advisory until 7 PM CDT this evening for TXZ254-255-351-354- 355. High Rip Current Risk through Saturday evening for TXZ451-454- 455. GM...Small Craft Advisory until 7 PM CDT this evening for GMZ130-132- 135. && $$ SHORT TERM...23-Evbuoma LONG TERM....22-Garcia AVIATION...23-Evbuoma