920 FXUS64 KBRO 151942 AFDBRO Area Forecast Discussion National Weather Service Brownsville TX 242 PM CDT Sun May 15 2022 .SHORT TERM (Tonight through Monday Night): Visible satellite imagery shows clear skies across most of Deep South Texas this afternoon, except for some fair weather cumulus across portions of the coastal counties. Cloud cover will increase slightly overnight both tonight and Monday night, but skies should be mostly clear during the daytime hours for today and Monday...so be sure to protect your skin if you plan on spending time outside as the UV Index is Extreme. Mid level ridging will continue to dominate through the short term period. Subsidence from the ridge combined with ample dry air above a shallow moist layer at the surface will maintain rain-free conditions over the next couple of days. With high pressure over the Gulf of Mexico, winds will remain southeasterly across Deep South Texas, with a typical diurnal fluctuation in wind speeds (breezy during the daytime hours dropping off to become lighter overnight). Models are hinting at some more patchy to areas of fog developing overnight for the Brush Country, with minimal, if any, reductions in visibility across the Valley. Morning low temperatures on Monday will dip into the upper 60s to lower to mid 70s, and then reach the 80s along the coast, the lower to mid 90s in the Lower Valley, all the way up to the triple digits for areas mostly west of I-69C/U.S. 281. It will feel hot, but heat indices will likely stay in the 99 to 105 degree range. Monday night lows will be slightly warmer than tonight's, only really dipping into the lower to mid 70s. .LONG TERM (Tuesday through Sunday): Hot and dry weather is expected through much of the period with heat advisories possible Friday and Saturday. There is also a glimmer of a chance for rain next weekend. We shall see. Synoptically, an H5 ridge axis will stretch from eastern Texas down into western Mexico Tuesday afternoon. A series of shortwaves traversing the middle part of the country will shunt the ridge axis south as mainly zonal flow develops overhead Wednesday and Thursday. A larger H5 trough digs into the Intermountain West, which will help spawn a series of surface lows along the Front Range. These lows tighten the pressure gradient so that we become breezy to windy later in the week. Meanwhile, higher dew points are forecast to sweep in from the southeast on Thursday, which means overnight lows will gradually warm through the period. Tuesday night will generally be in the lower to middle 70s across the county warning area (CWA) before warming into the middle to upper 70s to near 80 by Friday night. The increase in surface moisture (those higher dew points) coupled with daytime highs remaining in the middle to upper 90s for much of the CWA and lower to middle 100s in the Rio Grande Plains and the western portion of the Upper Rio Grande Valley means heat indices could push to near 111 degrees or above as soon as Friday. Thus Heat Advisories may be needed for those areas Friday and Saturday. Okay, so I mentioned above about a glimmer of hope for a chance for rain next weekend. Well, that stems from a possible cold front attempting to near Deep South Texas and the Rio Grande Valley. Models aren't in great agreement about how it arrives nor how much rain it might bring, but the NBM and ensembles do suggest that at least a couple of showers may be possible. Granted, even the NBM has less than a 20 percent chance for rain this far out, so it's not exactly a given. Still, it is something we'll monitor through the week. && .MARINE: Now through Monday Night...Buoy 42020 is showing wave heights around 3 feet with a dominant period of 5 seconds and moderate south to southeasterly winds, indicating fairly pleasant boating conditions offshore. However, winds are a bit stronger near shore, at 15 to 20 knots, with Small Craft Exercise Caution (SCEC) conditions across the Laguna Madre and nearshore Gulf waters expected to continue this afternoon through the overnight hours. Seas subside slightly tonight, but winds and seas pick up again on Monday, with SCEC conditions likely across all lower Texas coastal waters. Tuesday through Sunday...Small Craft will need to exercise caution to begin the period due a persistent south to southeasterly breeze at 15 to 20 knots. Seas begin to build and winds increase as the pressure gradient tightens over the Lower Texas Coast for the second half of the work week. This will lead to conditions near Small Craft Advisory criteria by Tuesday night that will likely continue through much of the period. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 72 91 74 90 / 0 0 0 0 BROWNSVILLE 74 93 75 92 / 0 0 0 0 HARLINGEN 68 96 73 95 / 0 0 0 0 MCALLEN 72 98 73 97 / 0 0 0 0 RIO GRANDE CITY 69 101 71 101 / 0 0 0 0 SOUTH PADRE ISLAND 76 82 76 83 / 0 0 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ This product is also available on the web at: https://weather.gov/rgv Short Term...69-Farris Long Term...58-Reese