838 FXUS64 KBRO 010840 AFDBRO Area Forecast Discussion National Weather Service Brownsville TX 340 AM CDT Sat Apr 1 2023 ...New SHORT TERM, LONG TERM, MARINE... .SHORT TERM... (Today through Sunday) Issued at 338 AM CDT Sat Apr 1 2023 The strong system working through the Plains will swing east through the Great Lakes today, with a bowling ball of low pressure working into Baja California, and the subtropical ridge edging west across the Southern Gulf, turning 500 mb flow across Deep South Texas more zonal into Sunday. A few perturbations in the 500mb flow slide by through the short term, with the first arriving this morning and the next late this evening into early tonight. The Baja shortwave runs from West Texas Sunday morning to Northeast Texas through Sunday afternoon. At the surface, a weak frontal boundary has pretty much stalled across the CRP CWA, and will eventually move further north into Sunday. A weak surface low may develop along the front west of Zapata and Starr counties, potentially bumping rain chances up as the energy aloft flies by. Have still kept POPs generally below 20 percent this morning into early this afternoon, and again along the border this evening into early Sunday morning. Prospects remain dim for any real beneficial rainfall. High temperatures today may mostly hang on cloud cover and any rain late morning into early afternoon, likely still topping mid 80s to low 90s for most inland locations. Highs on Sunday should gain a few degrees with increased southerly flow and less cloud cover. && .LONG TERM... (Sunday night through Friday) Issued at 338 AM CDT Sat Apr 1 2023 Above normal temperatures and rain-free conditions are expected until midweek. A nearly zonal flow Sunday night will turn southwesterly by Monday night as the next upper level storm system moves into the Rockies. At the surface, the pressure gradient will strengthen Monday into Tuesday as low pressure moves into the Plains. This will enhanced winds over portions of Deep South Texas, especially near the coast. A Wind Advisory may be needed on Monday for the Lower Rio Grande Valley. The breezy to windy southerly flow will also lead to warming temperatures through Tuesday. The 500mb trough swings over the Northern Plains Tuesday night into Wednesday and pushes a cold front into the region late Wednesday into Thursday. However, the current forecast does not have the frontal boundary making it through Deep South Texas. It is possible that the front could stall out to the north or somewhere in Deep South Texas. This cold front is anticipated to bring isolated to scattered showers and thunderstorms to the region as the front stalls. Rain chances will linger into Friday and maybe in the Saturday with the stalled frontal boundary across the area. As for temperatures, low temperatures Sunday night through Tuesday night will be mostly in the 70s, but there will be some areas in the Northern Ranchlands in the upper 60s. Highs Monday and Tuesday will range from the 70s at the beaches, the mid to upper 80s near the coast and the 90s inland. There is the possibility of triple digit temperatures for the Upper Valley and the Brush Country on both of these days. High temperatures will be slightly cooler on Wednesday with most of Deep South Texas in the upper 80s, with some pockets in the the 90s, while the low temperatures will be in the 70s. Thursday temperatures will be cooler due to the abundant cloud cover and increase in rain chances keeping our highs mostly in the 80s with some places being in the upper 70s. The highs for Friday will slightly warm up as the rain and clouds become less prevalent over the region to the 80s. The lows will be in the range of upper 60s to low 70s for Thursday and Friday. && .AVIATION... (06Z TAFS) Issued at 1229 AM CDT Sat Apr 1 2023 IFR to MVFR conditions are expected to continue into mid Saturday morning before VFR ceilings return into the evening. Southeasterly winds are expected through the period. Patchy fog may reduce visibility late tonight across the RGV. && .MARINE... Issued at 338 AM CDT Sat Apr 1 2023 Now through Sunday...A long period easterly swell is expected to continue through this weekend. A weak frontal boundary may not make it this far south and light onshore winds today maintain more favorable marine conditions. Winds turn more southerly on Sunday and increase slightly into the afternoon, especially across the Laguna Madre. Small Craft Caution to borderline Small Craft Advisory conditions are expected Sunday afternoon, mainly on the bay, with choppy conditions. Sunday night through Friday...Generally favorable conditions through Monday morning. Winds are expected to increase late Monday into Tuesday as the pressure gradient strengthens along the Lower Texas Coast. Small Craft Exercise Caution conditions are expected for much of the period. Low end Small Craft Advisory conditions are also possible late Tuesday into Wednesday due to the stronger winds and higher seas. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 84 72 88 72 / 10 10 0 0 HARLINGEN 89 71 89 72 / 10 10 0 0 MCALLEN 89 72 91 73 / 10 20 0 0 RIO GRANDE CITY 90 72 94 71 / 20 20 0 0 SOUTH PADRE ISLAND 77 71 78 71 / 10 10 0 0 BAYVIEW/PORT ISABEL 82 71 82 71 / 10 10 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...56-Hallman LONG TERM....63-KC AVIATION...56-Hallman