Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
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926 FXUS64 KBRO 112347 AAA AFDBRO Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 647 PM CDT Tue Jun 11 2024 ...New AVIATION... .SHORT TERM... (Tonight through Wednesday night) Issued at 138 PM CDT Tue Jun 11 2024 The ongoing summer weather pattern will continue in the short term. A broad, mid-level trough axis over East Texas will shift east over the Northwest Gulf by Wednesday night. For the rest of today, though, that trough will interact with a stalled frontal boundary to our north, and some convection could push toward South TX tonight. Short range models are not confident about pushing anything into or through the CWA tonight, however. That said, look for partly cloudy skies tonight with light onshore winds and low temperatures from the mid 70s to near 80 degrees. The light winds may support patchy to areas of light fog for the Northern Ranchlands and Mid-valley late tonight. The global weather forecast models advertise a rebuilding H5 ridge over Northwest Mexico into the Desert Southwest. On the leeward side of the ridge axis, deep South Texas and the Rio Grande Valley will see slightly above normal temps. Max temps on Wednesday will range from the mid 90s east to near the century mark far west. Afternoon heat index values, then, will be in the 105 to 110 degree range, below heat advisory criteria, though heat index values could briefly touch 111 degrees in a limited number of spots. Winds should remain light to moderate with mostly sunny skies on Wednesday. A sea breeze will initiate just before noon on Wednesday. PWAT will be similar to, or slightly higher than today. The CWA remains in a general thunderstorm category outlook area, and a few showers or tstorms could develop along the sea breeze on Wednesday. The sea breeze line has not been able to build enhanced showers today with the lower PWAT values. A healthy increase in PWAT will be possible on Thursday based on forecasted soundings, so a few more showers may develop then. As for Wednesday night: warm and muggy under partly cloudy to mostly clear skies with light winds. Low temps will range from the mid 70s to near 80 degrees. We`re a few days past a new moon, with greater illumination each night. Rip current risk should remain low due to low wave heights. && .LONG TERM... (Thursday through next Tuesday) Issued at 138 PM CDT Tue Jun 11 2024 A mid/upper level ridge axis centered across the Mexican state of Chihuahua will prevail through Thu and Fri. The overall ridging aloft does weaken its influence on our CWA over the weekend with the approach of a southern stream closed low/shortwave moving across the Great Basin into the Plains. At the same time, an inverted trough axis will be developing across the eastern and central Gulf. So through Sat, most of the CWA is expected to maintain mostly dry conditions with continued slightly above normal temperatures. Heat indices are expected to remain below heat advisory thresholds at this time. There still will be the potential for a slight chance to low chance of convection mainly seabreeze-enhanced and diurnally-driven. Most of the convection through Sat is expected to remain mainly east of I-69C. An increasingly unsettled synoptic weather pattern is expected to develop Sun through Tue of next week across our CWA. The inverted trough axis with PWATs between 2.5 and 2.8 inches poised along and east of this axis will slowly move westward through Tue. The inverted trough axis will reach the CWA by Mon and begin to move through the CWA on Tue. The net result will be a significant moistening of the entire tropospheric column given this deep moisture advection, especially on Mon and Tue. POPs will slowly increase during the Sun-Tue time period and will be mostly in the chance to likely POP range by Tue. Heavy rain at times will be a given but with the worsening drought conditions of late, most of this rainfall is expected to be welcome relief, especially for the parched watershed. There does appear to be some potential for limited tropical cyclone development early next week. While the models are still a bit chaotic, they are coming into somewhat better agreement in potentially signaling a potential TD or even a weak TS development in the Bay of Campeche early next week. Any potential landfall would appear to stay in the favored region between Tampico and Veracruz, well to our south. But of course, we will need to monitor this potential scenario as northward reformation has been known to occur with many weak W Gulf systems. Will lean towards a Bay of Campeche potential development area as this is a favored climatological region for TC development. Also, a broad high pressure area entrenched across the central and eastern Gulf further points to a more southerly development area. Besides the rain, there will be an increased risk of rip currents with the potential for minor tidal overflow early next week due to incoming building swells originating from a developing moderate to strong southeast gradient flow. With the increase in cloud cover and rain chances, temperatures are expected to slowly come down to more typical mid June levels by early next week. && .AVIATION... (00Z TAFS) Issued at 631 PM CDT Tue Jun 11 2024 Mostly clear skies and moderate east-southeast winds prevail across Deep South Texas early this evening. Winds will decrease and become light overnight into Wednesday morning. East to southeast winds will increase and become moderate in the afternoon. VFR conditions are expected for the next 24 hours, with the exception of brief MVFR in any heavier showers or storms that develop. && .MARINE... Issued at 138 PM CDT Tue Jun 11 2024 Now through Wednesday night...A weak pressure gradient will produce mainly light to moderate east to southeast winds and low to moderate seas through the short term. Broad, mid-level troughing setting up over the northwest Gulf will support an increase in marine showers and thunderstorm activity. Thursday through next Tuesday...Weak to moderate easterly flow will prevail through Sat across the lower Texas coastal waters with broad high pressure centered across the TN and MS valley regions. Isolated to scattered convection will still be possible as just enough moisture and forcing prevails. Rain chances will increase beginning on Sun as an inverted trough axis with copious amounts of deep tropical moisture associated with it advances westward with time. Meanwhile, a long fetch of moderate to strong southeast gradient flow of 20-25 kts with a few pockets of 30 kts will develop early next week across the southern Gulf and portions of the western Gulf as the overall gradient in the Gulf tightens. The net result will be building seas/swells beginning on Sun. Small craft advisories appear likely by Mon and Tue as the larger swells arrive. As was stated above, there is also the potential for TC development early next week across the Bay of Campeche. Depending upon how this event unfolds, the winds and seas could be higher than what is currently forecast. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 79 96 79 95 / 0 20 10 30 HARLINGEN 76 97 75 96 / 0 20 0 20 MCALLEN 79 100 79 98 / 0 20 0 20 RIO GRANDE CITY 78 100 79 98 / 0 10 0 10 SOUTH PADRE ISLAND 82 87 82 87 / 10 20 10 30 BAYVIEW/PORT ISABEL 79 92 79 92 / 0 20 10 30 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...54-BHM LONG TERM....80-MB AVIATION...63-KC