Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
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632 FXUS64 KBRO 172330 AAA AFDBRO Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 630 PM CDT Sat Aug 17 2024 ...New AVIATION... .SHORT TERM... (Tonight through Sunday night) Issued at 230 PM CDT Sat Aug 17 2024 Upper-level ridging along the Rocky Mountains will continue to build through the period, generally supporting broad subsidence and relatively dry mid-level flow across the region. This will work to keep rain chances low through most of the period, however a brief increase in mid-level moisture Sunday afternoon will provide an opportunity for increased rain chances. At the surface, high pressure is expected to remain in control across the Gulf of Mexico, with a weak pressure gradient across Deep South Texas. This will support light to calm winds overnight tonight, with southeasterly winds picking up Sunday morning as the sea breeze develops. Weak forcing along the sea breeze, combined with an uptick in PWATs (values exceeding 2) and CAPE (>1500 J/kg), will allow rain chances to increase to around 20% Sunday afternoon. The majority of the convection looks to remain generally along and west of I-69C. Heat will continue to remain a concern through the period, with high temperatures Sunday ranging from the upper 90s to low 100s. Heat indices will likely reach 110 across the eastern half of the CWA, with a few locations briefly reaching 112. A special Weather Statement will likely be needed for eastern portions of the CWA, though a Heat Advisory cant be ruled out. Overnight temperatures tonight and Sunday night are expected to be in the mid 70s to low 80s. && .LONG TERM... (Monday through next Saturday) Issued at 230 PM CDT Sat Aug 17 2024 Key Messages: * There is a moderate risk of hazardous heat through the week. Heat advisory conditions will be possible from at least Monday through Thursday afternoons, with the risk easing some at the end of the week. * We do not expect tropical cyclone formation for the Gulf. As suggested above, sizzlingly hot weather will be at the fore in the long term. A 594 dam (plus) mid-level ridge will be anchored over the southern High Plains through Thursday, with broad high pressure covering the Gulf and South Texas. This pattern will send high temperature readings to the century mark and higher for most inland areas. Dew points in the mid 70s over eastern sections will support heat index values slightly above 110 degrees (heat advisory criteria) each afternoon for inland areas covering the eastern half of the CWA. Beyond Thursday, the ridge will shift west and be replaced by a broad, inverted mid-level trough. This pattern shift will "break" the heat somewhat, and though temps will still remain near to above normal, the risk of hazardous heat/heat advisory conditions will lower. Coastal rain chances will likewise increase slightly Friday and Saturday as mid level heights over the region decrease and West to Southwest Gulf instability reemerges. Rip current risk will be suppressed through the long term due to lower wave heights. && .AVIATION... (00Z TAFS) Issued at 628 PM CDT Sat Aug 17 2024 VFR conditions are expected to prevail through the TAF period, with any lingering southeasterly breeze diminishing into early tonight from east to west. Isolated sea breeze showers or thunderstorms are possible again Sunday afternoon, mainly north of the RGV aerodromes. && .MARINE... Issued at 230 PM CDT Sat Aug 17 2024 Tonight through Sunday night...Favorable marine conditions are expected to continue through the period as surface high pressure remains in place across the Gulf of Mexico. This will support a weak pressure gradient along the Lower Texas Coast, which in turn will foster generally light to moderate winds and slight seas. Some isolated showers and thunderstorms could be possible Sunday, and locally higher winds and seas could be produced by any storms that do develop. Monday through Thursday night...High pressure will result in mostly light to moderate winds and low to moderate seas. East to southeast winds on Monday will turn more southerly Tuesday onward. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 80 95 80 96 / 0 20 0 10 HARLINGEN 77 96 76 97 / 0 20 0 0 MCALLEN 80 100 79 102 / 0 20 0 0 RIO GRANDE CITY 78 100 78 101 / 0 10 0 0 SOUTH PADRE ISLAND 82 90 83 90 / 0 10 0 0 BAYVIEW/PORT ISABEL 79 92 79 93 / 0 10 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...60-BE LONG TERM....54-BHM AVIATION...56-Hallman