Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
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694 FXUS64 KBRO 092004 AFDBRO Area Forecast Discussion National Weather Service Brownsville TX 304 PM CDT Sun Jun 9 2024 ...New SHORT TERM, LONG TERM, MARINE... .SHORT TERM... (Tonight through Monday night) Issued at 305 PM CDT Sun Jun 9 2024 Key messages: * Closer to seasonal temperatures return...though still closer to late June than mid June * Sea breeze should produce isolated to scattered showers and a possible thunderstorm Monday but not enough rain to dent soil moisture deficits * Great weather for the beach when combining low waves and currents with warm surf and cleaner air Believe it or not...a little bit of "normal" June weather returns to begin the work week. While temperatures will remain a couple degrees above average tonight and Monday, the low level pattern returns to a more summer-like east to east-northeast flow...albeit light...by Monday afternoon. The 500 mb pattern continues to feature a La Caninula-like ridge, but its intensity is more in line with what we`d expect in early to mid June. At the same time...deep layer moisture continues to creep upward and blended model precipitable water values reach to or just above 2 inches. That means the low level onshore flow combined with the moisture should be enough to kick off a day of isolated to scattered sea breeze showers and a few storms. With limited forcing, however, not expecting prolonged rainfall or any notable impact to the dryness/parched soil moisture condition...but a little rain along with more azure blue skies is quite the welcome site after so many weeks of polluted haze and smoke (which had begun to recede gradually after the start of June). In terms of sensible weather...the only other concern is whether any upstream convection...courtesy of weak energy rotating around the front side of the aforementioned ridge...can reach the northern ranchlands and Rio Grande Plains this evening. Model blends are bearish but deterministic model (i.e. GFS) is a bit more bullish. For now, have left mentionable rain out of the forecast but will need to keep eye on radar for potential between 7 PM and midnight. Otherwise, another sultry night as evening southeast winds drop overnight but remain at or above 5 mph which should keep lows around 80 for the populated RGV and upper 70s elsewhere. For Monday, the light morning southeast winds will back easterly around noon, and with aforementioned moisture uptick expect isolated sea breeze convection to develop just inland from the coast between 11 AM and noon. Convection likely to start sooner in the Gulf and could sneak onto the barrier island before 11 AM...but typically we see convection "jump" west and miss the resort areas completely. Blended forecast catches this by 4 PM...but likely to see the beaches cleared out (except for offshore towers) by 1 PM or sooner. Inland...sea breeze should kick off disorganized isolated to scattered showers and a few thunderstorms, peaking between 2 and 5 PM as they nose westward into the mid/upper Valley. High temperatures may be briefly impacted by the rain or nearby boundaries...but typically we see highs near average in such a situation (especiallly the first of the summer) so blended values of 94 to 98 for most looks on target. Convection should end by late afternoon, perhaps early evening across the Rio Grande Plains, followed by clearing skies and temperatures falling a few degrees lower than tonight based on near calm late night winds. Precipitation type grids have put patchy to areas of fog...visibility probably in the 1 to 3 mile range toward daybreak Tuesday...and this seems reasonable given the slightly lower temperatures and near calm wind. && .LONG TERM... (Tuesday through next Sunday) Issued at 305 PM CDT Sun Jun 9 2024 Much of the forecast will be dominated by mostly sunny/clear skies and light to moderate breezes. Mid-level ridging to the west will be in control Tuesday. A short-wave trough/mid-level low over northeast Texas will edge east Tuesday night, but not before sending a burst of energy south toward Central Texas and the Coastal Plains. Currently, the energy looks like it will dissipate before significantly impacting the RG Plains and/or the Upper Valley of deep South Texas. Heading into mid-week, mid-level ridging over the Southwest United States will build, with high pressure over the lower Mississippi Valley extending over the Northwest Gulf. A broad upper trough will lie roughly over the same area, destabilizing the West Gulf of Mexico and supporting a seasonal increase in shower activity. The ECMWF envisions sea breeze events Tuesday through Friday, with pops in the grids being slightly more robust on Tuesday. In the meantime, later this week, the ridging over the Southwest U.S. will break down and shift east over portions of Texas. It will be replaced upstream by a filling cutoff low lifting into the Central High Plains. Rump ridging will remain across North Mexico and along the Texas portion of the Rio Grande, however. The main impact for next weekend, then, may only be a better chance of Gulf showers affecting mainly the middle and upper Texas Coast. The main hazard of concern in the long term, heat, will remain restrained from extreme values. Still, overall temperatures will continue to run a few degrees warmer than normal for this time of year. The NBM advertises low temperatures generally in the mid to upper 70s. High temperatures may poke above the century mark out west each afternoon, but most areas will be looking at mid to upper 90s. Only next Sunday, at the end of the period, will high temps creep a few degrees higher and flag a possible low end heat advisory. && .AVIATION... (18Z TAFS) Issued at 305 PM CDT Sun Jun 9 2024 Overall...same forecast (from Saturday) but different day. Few to scattered VFR cumulus this afternoon at the lower Valley terminals with any low clouds clearing out at McAllen by mid afternoon. We`ll also see the usual east to west movement of the enhanced southeast flow with gusts around 20-22 knots at Brownsville and Harlingen through sunset...and 24 knots at McAllen just before sunset for a couple hours after. For the overnight...other than scattered MVFR fractus clouds...we`ll need to keep an eye on any residual mid/high clouds from any convection that develops in central/south central Texas as weak short wave energy rotates through the general upper level ridging overnight. Not expecting any of this convection or residual rain and lower clouds to reach the Valley terminals at this point. Quick develop scattered-broken low VFR cumulus again Monday morning with slightly lower southeast wind speeds. && .MARINE... Issued at 305 PM CDT Sun Jun 9 2024 Tonight through Monday night...A continued easing of winds and seas through the period as the surface ridge expands back west across the waters. Seas were just below 3 feet this afternoon but should fall to 2 feet across the waters tonight and remain through Monday night. Southeast winds will gradually drop below 10 knots later tonight, then back to the east at 10 knots or less Monday and continue through Monday night. As for rain...expect isolated to scattered showers and perhaps a thunderstorm to begin later tonight and continue through Monday early afternoon before fading as is typical with sea breeze inland shifts...then resume but isolated at most Monday night. Tuesday through Friday night...A weak pressure gradient will support light to moderate east to southeast winds and low to moderate seas through the forecast. In this summer regime, marine convection will become more active, resulting in periodic isolated to scattered Gulf showers. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 82 96 79 95 / 0 20 10 30 HARLINGEN 78 96 76 97 / 0 30 10 20 MCALLEN 81 98 79 99 / 0 30 20 20 RIO GRANDE CITY 80 97 78 98 / 10 20 30 10 SOUTH PADRE ISLAND 83 88 81 87 / 10 30 10 30 BAYVIEW/PORT ISABEL 80 93 79 92 / 0 30 10 30 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...52-Goldsmith LONG TERM....54-BHM AVIATION...99