Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
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968 FXUS64 KBRO 211733 AAB AFDBRO Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 1233 PM CDT Tue May 21 2024 ...New AVIATION... .SHORT TERM... (Today through Wednesday) Issued at 304 AM CDT Tue May 21 2024 594dm Subtropical Ridge anchored over N Mexico and South Texas to maintain the above seasonal heat and keep our region rain free today through Wednesday. 850mb temperatures of 22-24C, dew points in the upper 70s to upper 60s support heat indices in the 110-115 range for all areas with except to the coast and Island counties. A heat advisory will be issued from 1-6 PM to cover the dangerous heat today. Another heat advisory is possible Wednesday with no substantial change to the airmass or the position of strength of the 500mb ridge. No relief overnight with minimums also remaining above normal with mid 70s to 80 degrees as low as they go with a modest southeast breeze and some increasing overnight cloudiness keep any radiational cooling at a minimum or zero. Otherwise, morning lower clouds break up fairly quickly each mid to late morning with plenty of afternoon and early evening Sun along with some afternoon gustiness. Also, hazy skies persist with agricultural fires from southeast Mexico continue to spread north with the southeasterly flow. Local air quality will be impacted with AQI in the `Unhealthy for Sensitive groups" forecast for the RGV including the lower coast today and Wednesday. && .LONG TERM... (Wednesday Night through Monday) Issued at 304 AM CDT Tue May 21 2024 Building heat will be the main concern during this portion of the total forecast. The BRO CWFA will remain on the northern periphery of 500 mb high pressure centered over Mexico, resulting in well above normal daytime high and overnight low temperatures. A HEAT ADVISORY is a near certainty daily beginning on Thursday, and an EXCESSIVE HEAT WARNING cannot be ruled out entirely beginning on Friday, with areal coverage of the WARNING likely being the key factor each day as to whether or not it is issued. Additionally, the presence of the 500 mb high will result in dry weather, with no precipitation anticipated. However, beyond the end of the Long Term period, on Tuesday night and Wednesday, some model guidance suggests that the passage of a mid-level shortwave may generate a wave of strong to severe thunderstorms through Deep South Texas and the Rio Grande Valley with welcome/needed rainfall at that time. && .AVIATION... (18Z TAFS) Issued at 1228 PM CDT Tue May 21 2024 Mostly MVFR conditions are expected to occur off and on during the TAF cycle at all TAF sites. VFR conditions are expected to last through the afternoon and into the evening hours before giving away to mostly MVFR. Southeasterly winds are expected to hold through the period while being gusty during the afternoon. The winds are expected to weaken during the evening hours and remain light through the overnight hours before picking back up again late in the morning again tomorrow. && .MARINE... (Today through Wednesday) Issued at 304 AM CDT Tue May 21 2024 A moderate pressure gradient persist over the Lower Texas coastal as a high pressure ridge extends from Florida to the SW Gulf of Mexico. Moderate to locally fresh southeast winds and slight to moderate seas can be expected today through Wednesday. (Wednesday Night through Monday) High pressure over the Gulf of Mexico will interact with thermal low pressure over Mexico to produce an enhanced pressure gradient along the Lower Texas Coast through the period. Small Craft Should Exercise Caution and/or Small Craft Advisory is likely to be needed daily to account for the breezy winds and elevated seas. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 97 81 96 81 / 0 0 0 0 HARLINGEN 97 77 98 78 / 0 0 0 0 MCALLEN 101 80 101 80 / 0 0 0 0 RIO GRANDE CITY 103 79 104 78 / 0 0 0 0 SOUTH PADRE ISLAND 87 82 86 81 / 0 0 0 0 BAYVIEW/PORT ISABEL 94 79 94 79 / 0 0 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...Heat Advisory until 6 PM CDT this evening for TXZ248>255-353. GM...None. && $$ SHORT TERM...59-GB LONG TERM....66-Tomaselli AVIATION...64-Katz