Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
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048 FXUS64 KBRO 110526 AAA AFDBRO Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 1226 AM CDT Tue Jun 11 2024 ...New AVIATION... .SHORT TERM... (Tonight through Tuesday night) Issued at 327 PM CDT Mon Jun 10 2024 Boundary driven convection with sea breeze interaction are affecting the CWA today (we are in a general thunderstorm category outlook area). Another southward moving pulse may move into the area evening, but most, if not all, convection should be finished by late evening. Look for another warm and muggy night. Overnight low temps will be in the mid 70s to near 80 degrees Fahrenheit with light east to southeast winds and partly cloudy skies. Tuesday will feature a similar setup compared to today. Low level moisture will again be high (PWAT today at KBRO was 2.15 inches) and should support late morning to early afternoon sea breeze formation. Due to the weakness over North Central Texas, convection may again fire to our north overnight and send an outflow boundary south toward deep South Texas and the Rio Grande Valley. The NAM12 shows just that type of scenario playing out. Have left the 20 to 30 percent pop area in for tomorrow reflecting at least sea breeze activity. However, we are in a general thunderstorm category outlook area for Tuesday and ultimate coverage could increase. Still on the leeward side of a temporarily weakened sub-tropical heat dome and ridge axis over North Central Mexico and the Southwest United States, temperatures will remain above average. That said, daytime high temps will be in the mid to upper 90s to near or slightly above the century mark inland west. This will be a few degrees above average. Accordingly, most CWA heat index values will be in the 105 to 110 degree range on Tuesday, with a small chance for some areas to briefly near or reach heat advisory criteria. Anticyclonic flow over the Gulf will support light east to southeast winds in the short term as well as isolated periodic Gulf showers. Wave heights will remain low supporting a low risk of rip currents. && .LONG TERM... (Wednesday through next Monday) Issued at 327 PM CDT Mon Jun 10 2024 Key Messages * Still hot, but closer to mid June averages each day and night * Isolated to scattered sea-breeze and boundary-driven late morning through late afternoon showers and storms, but not enough rain to make a prolonged dent in heat * Rip currents will become moderate by Friday through the weekend, posing a danger to unaware swimmers in otherwise favorable surf The big picture is still hot and generally rain-free, though a gradual pattern change aloft will help bring some sea-breeze activity each day through Thursday...and generally easterly flow in the low levels will continue to remove the hazy skies and bring more typical tropical azure blue skies with each passing day. As for that rain...the better chances on land continue to favor Wednesday and Thursday as additional weak short waves dive southward on the east side of the north-south axis 500 mb ridge initially centered over New Mexico through Chihuahua Mexico and southwest to Sinaloa/Baja. By Friday, that ridge "tips" over and expands eastward, extending from the lower Mississippi Valley through most of Texas and out to Baja...which will push any short waves rotating around the ridge well east of the area. This should put an end to mentionable rain on land, though isolated showers will be possible over the warm Gulf waters where hints of higher moisture remain. Any sea breeze driven rains will follow diurnal trends which means morning to around noon on the island and jumping inland soon after, leaving the beaches mainly sunny with distant cumulus towers 20-60 nautical miles out. Of course, any southward-moving boundaries from activity to our north could change the situation, as was the case today. The dry air should hold through at least Sunday, but the forecast becomes more uncertain Sunday night and Monday as the ridge breaks ito two pieces, one recentering over Baja and the other along the southeast U.S. coast. As the east coast ridge strengthens a bit, it will tend to send at least some of the deep tropical plume of moisture affecting Florida for the rest of this week westward into the central Gulf late Sunday...and perhaps nosing toward the entire Texas coast by next Monday. This is where uncertainty really grows as models are in different camps and the question remains just how far west the plume can move...especially since the 500 mb trough (acting like a Tropical Upper Tropospheric Trough, or TUTT) has a north-south axis and the west side, which would include the coast, could stay dry for at least the first day or two next week. The latest National Blend of Models is more bullish with the approach of deep layer moisture, and thus has Monday in a 20-40 percent chance of tropical showers and perhaps a thunderstorms for all but the Rio Grande Plains. The blend accounts for multiple permutations...so expect this part of the forecast to change over the next several days. As for temperatures...the overall atmosphere remains above average based on traditional parameters such as 1000-850 and 1000-500 mb thickness, 850 mb temperatures, etc...but the pattern is less favorable for the blast furnace effect that we saw for much of the past six weeks. Therefore, have temperatures sitting 1-2 degrees above average (upper 90s east, 100-102 west) for mid June by day but right around average each morning with light winds and mainly clear skies. Still...with temperatures still on the slightly higher side after a searing hot start to June...our average values through mid June will end up at or near the hottest on record. Finally...with the beach offering another weekend of relief...and azure blue skies with increasing easterly swell...the danger of moderate pure rip currents lurks as surf temperatures will be in the inviting mid 80s. Poor swimmers are urged to be near lifeguards and only venture in to waist or knee deep during this time. && .AVIATION... (06Z TAFS) Issued at 1226 AM CDT Tue Jun 11 2024 Through 06z Wednesday....VFR conditions are expected to persist through the entirety of the 06z TAF cycle as a sfc high pressure maintains control over the region. Light and variable to calm winds overnight will give way to east- southeast winds between 5-10 kts today. && .MARINE... Issued at 327 PM CDT Mon Jun 10 2024 Now through Tuesday night...High pressure over the north-central Gulf of Mexico and a weak pressure gradient over the region will produce light to moderate east to southeast winds and generally low seas through the forecast. Convection over the Gulf will be more active this week, with periodic isolated showers and thunderstorms along the lower Texas coast. Wednesday through Saturday night...Other than periodic isolated to scattered showers and a few thunderstorms much of the time (mainly from late night through early afternoon), winds/seas begin on the light/slight side before increasing a bit by Saturday as easterly swell gets going between the weak ridge in the northern Gulf and weak low in the southwest Gulf. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 96 79 96 80 / 30 0 20 10 HARLINGEN 97 76 97 75 / 30 0 20 10 MCALLEN 100 78 99 78 / 20 0 10 0 RIO GRANDE CITY 100 78 99 78 / 10 0 10 0 SOUTH PADRE ISLAND 87 81 87 81 / 30 10 20 10 BAYVIEW/PORT ISABEL 92 78 92 78 / 30 0 20 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...54-BHM LONG TERM....52-Goldsmith AVIATION...23-Evbuoma