Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
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395 FXUS64 KBRO 160213 AAB AFDBRO Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 913 PM CDT Wed May 15 2024 ...New UPDATE... .UPDATE... Issued at 908 PM CDT Wed May 15 2024 POPs were lowered this evening due to inactivity over the Sierra Madre. Brownsville OOZ sounding indicated a large cap over the region and with no significant disturbance within the southwest flow aloft, deep convection is not anticipated to develop tonight. Isolated streamer showers are possible after midnight over the Gulf of Mexico with a few possibly nearing the lower and middle RGV. && .SHORT TERM... (Tonight through Thursday night) Issued at 254 PM CDT Wed May 15 2024 Key Messages: - There is a low chance (20-30%) of showers and thunderstorms late this evening across the Northern Ranchlands. - The combination of above normal temperatures and humidity will result in triple-digit heat index values across Deep South Texas. - A Heat Advisory may be needed for portions of the region Thursday afternoon. Radar and satellite imagery depict rain-free conditions and partly cloudy skies across Deep South Texas. Low level southerly to southeasterly flow will increase in speed in response to an approaching upper level trough from the Desert Southwest. This will result in stratus clouds spreading across the region by this evening, in addition to increasing precipitable water values. Isolated to scattered strong to severe thunderstorms are expected to develop along a dryline across the Texas Hill Country late this afternoon, and as far south as Mexico along the Sierra Madre mountains. Despite the presence of steep lapse rates, modest instability, high moisture content, and high shear values, weak forcing will limit the eastward extent of any strong to severe thunderstorms across the region late this evening and tonight. However, there has been run-to-run consistency that an isolated strong to severe thunderstorm or two will make it toward the Northern Ranchlands and Upper RGV after 9-10PM this evening. Any activity should be on a downward trend as it tracks east as instability wanes overnight. Otherwise, warm air advection showers may develop along the I-69 corridor tonight. The combination of increasing low level southerly flow and overcast skies will keep temperature in the 70s and low 80s tonight. Thursday will be another very warm day, with temperatures around 5-8 degrees above normal for mid May. In combination with the return of higher humidity, heat index values will approach the triple digits region wide. The exception will be along the Lower Texas beaches, where heat index values will remain in the 90s. Portions of Deep South Texas, mainly areas along/east of US-281, will likely realize "feels like" temperatures in the 111-115 range tomorrow afternoon. A Heat Advisory will likely be needed for Cameron, Willacy, Hidalgo, and Kenedy counties, but look marginal for Brooks County. Will hold off on issuing any heat headlines at this time, but an advisory may be needed for the eastern half of the CWA. Regardless of any heat headlines, the NWS HeatRisk tool highlights a major risk of heat-related impacts for those that are not properly hydrated or do not have effective cooling in place. Isolated showers may develop Thursday afternoon, mainly over the far northeastern zones, and increased cloud cover may temper the heat by a degree or two. Otherwise, another mild, humid, and cloudy night is expected Thursday night with lows in the upper 70s and low 80s. && .LONG TERM... (Friday through next Wednesday) Issued at 254 PM CDT Wed May 15 2024 Key Messages: - There is a low chance (20-30%) of showers and thunderstorms on Friday across Deep South Texas. - The combination of above normal temperatures and humidity will result in triple-digit heat index values across the region through next week. Overall, the long term forecast remains on track with mostly rain-free conditions expected through next week across Deep South Texas. The exception will be on Friday as a mid/upper level trough approaches the Texas Hill Country/South Texas on Friday. Ahead of this system, precipitable water values are forecast to be around 2-2.1 inches, well above the 90th percentile of 1.82 inches. Although the better forcing for ascent will be just north of the region, widely scattered showers and thunderstorms cannot be ruled out as instability increases through the day. Heading into the weekend and early next week, mid and upper level ridging will build in from the west/southwest. This will allow for a continued steady warming trend across Deep South Texas, with high temperatures warming into the upper 90s along the immediate coast to around 105-106 degrees across the Rio Grande Plains. Triple digit heat indices are expected each afternoon in combination with the humidity. Additional heat headlines may be needed by mid week next week. Despite any formal headlines, the NWS HeatRisk tool highlights a major risk of heat-related impacts for those that are not properly hydrated or do not have effective cooling in place. && .AVIATION... (00Z TAFS) Issued at 609 PM CDT Wed May 15 2024 Currently, MVFR ceilings are beginning to work inland and are expected to have spread across all TAF sites within a few hours following sunset and persist through tonight. Winds will gradually veer to more southeast in the early morning hours Thursday and continue as ceilings gradually lift to VFR by Thursday afternoon. && .MARINE... Issued at 254 PM CDT Wed May 15 2024 Tonight through Thursday night...Light to moderate winds and low to moderate seas will prevail through the period. A tightening pressure gradient will result in Small Craft Should Exercise Caution conditions along the Laguna Madre and nearshore Gulf waters Thursday afternoon. Friday through Wednesday...Light to moderate winds and low to moderate seas will prevail through next week. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 80 94 80 95 / 20 10 0 20 HARLINGEN 78 97 77 97 / 10 10 10 20 MCALLEN 80 100 80 99 / 10 0 10 20 RIO GRANDE CITY 78 100 78 98 / 10 0 10 20 SOUTH PADRE ISLAND 80 86 81 86 / 20 0 0 10 BAYVIEW/PORT ISABEL 80 92 78 93 / 10 10 0 20 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ UPDATE...65-Irish/59-Bogorad SHORT TERM...22-Garcia LONG TERM....22-Garcia AVIATION...65-Irish