Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
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988 FXUS64 KBRO 022316 AAA AFDBRO Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 616 PM CDT Thu May 2 2024 ...New AVIATION... .SHORT TERM... (Tonight through Friday night) Issued at 251 PM CDT Thu May 2 2024 Will key off the SPC Day 2 outlook to start, focusing on Friday night to Saturday morning. SPC places the County Warning Area in a general thunderstorm risk area, with the extreme Upper Valley in a marginal tstorm risk. The depicted SPC local area is essentially part of a southward extension of what is forecast to be more active convection over the southern High Plains on Friday. The southern extension of the Texas dryline will likely lie just to the west of the CWA Friday, extending south into Mexico along the Sierra Madre Oriental range. That appears to be where a tstorm threat will first become evident Friday afternoon. Confidence is still on the low side, 10 to 20%, and the window (timeframe) is limited. Otherwise, there may be patchy, light fog here and there overnight, mainly across the Northern Ranchlands and near/over marine areas. Rip current risk will likely continue to be moderate. Additionally, slightly above average (by a few degrees) temperatures will occur, tempered by ample cloud cover. Southeast winds will remain moderate to breezy. && .LONG TERM... (Saturday through next Thursday) Issued at 251 PM CDT Thu May 2 2024 Key Messages: * Temperatures off to the races as early-season heat expected to build into the area next week * Widespread triple digit heating expected Tuesday through Thursday * Heat indices are expected to range between 105F-115F degrees across all of Deep South Texas and the Rio Grande Valley Monday through Thursday * Little to no relief at night with overnight lows in the upper 70s to near 80F Monday night through Thursday night; elevated cooling degree days (CDDs) * Heat Advisories possibly needed Wednesday and Thursday with heat indices ranging between 110F-115F * HeatRisk scores range from Moderate to Extreme over the region Tuesday through Thursday of next week (heat will likely affect anyone without effective cooling and/or adequate hydration) The main weather headline during the long-term forecast period will be the HEAT. Global forecast models and ensembles (GEFS, CMC, ECE) continue to advertise unseasonably warm to hot conditions developing over Deep South Texas and the Rio Grande Valley next week. According to recent model runs, a 591 dam sub-tropical heat dome centered over central/southern Mexico is expected to strengthen and expand northeastward into Deep South Texas/Rio Grande Valley and the northern Gulf of Mexico next week. Current forecast indicates 500 mb heights ranging between 588-591 dam. Monday and Tuesday, 850 mb temperatures are expected to range between 22C-26C. By Wednesday and Thursday (the hottest period of this stretch), 850 mb temperatures are expected to range between 26C-30C. According to the NAEFS, these temperatures are +2 to +3 STDEVs above normal. This will translate to surface temperatures during the afternoon hours ranging from the mid 90s to about 110F degrees Tuesday through Thursday. When you factor in the elevated humidity levels (dewpoints in the low to mid 70s), widespread 100+ degree heat indices are expected. Monday and Tuesday, heat indices are expected to range between 105F-110F degrees. Wednesday and Thursday, again the peak of this early season heat episode, heat indices are expected to range between 105F-115F degrees. Heat Advisories may be needed Wednesday and Thursday. Our new HeatRisk Tool is scoring a continuation of mainly moderate heat risk Saturday through Monday. By Tuesday and Wednesday of next week, the HeatRisk increases to anywhere from moderate to extreme. This would suggest the likelihood of heat affecting anyone without effective cooling and /or adequate hydration, and little to overnight relief. People are urged to continue to monitor the latest forecast from the National Weather Service in Brownsville/Rio Grande valley (weather.gov/bro/). Leading up to this heat event, people should take a proactive approach and heed the necessary precautions to prepare for the heat. During the heat event next week, people should follow all precaution and guidelines (i.e. hydrate at all times, stay away from strenuous activities, wear light loose fitting cloths, check on the pets and elderly and move them to air conditioned facilities). && .AVIATION... (00Z TAFS) Issued at 610 PM CDT Thu May 2 2024 MVFR will prevail across BRO and HRL this evening with MFE falling to MVFR overnight. Moisture increases overnight and will allow ceilings to lower to IFR later tonight into Friday morning across all sites, before returning to MVFR by mid to later morning. Winds will decrease tonight and could allow for some patchy fog to develop near daybreak. && .MARINE... Issued at 251 PM CDT Thu May 2 2024 Tonight through Friday night...Moderate to fresh southeast winds and moderate to sometimes marginally high seas will prevail along the lower Texas Coast through the short term. High pressure will be in control over the Gulf, interacting with lower pressure deep inland and upstream to provide a gradient conducive to persistent southeast winds. Saturday through Thursday....Moderate winds and seas are expected to persist Saturday through Thursday. There could be times of Small Craft Exercise Caution (SCEC) conditions taking place through the long-term period. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 78 90 76 89 / 10 10 0 0 HARLINGEN 75 92 74 91 / 0 10 0 0 MCALLEN 78 94 77 93 / 0 20 10 0 RIO GRANDE CITY 76 94 75 94 / 0 20 10 10 SOUTH PADRE ISLAND 77 82 77 81 / 10 10 0 0 BAYVIEW/PORT ISABEL 76 87 75 87 / 10 10 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...54 LONG TERM....23 AVIATION...68