Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
301 FXUS64 KBRO 120844 AFDBRO Area Forecast Discussion National Weather Service Brownsville TX 344 AM CDT Wed Mar 12 2025 ...New SHORT TERM, LONG TERM, MARINE, FIRE WEATHER, CLIMATE... .SHORT TERM... (Today through Thursday) Issued at 251 AM CDT Wed Mar 12 2025 An upper level trough moving across the Central Plains today will drive a weak cold font south into northwestern portions of the CWA this afternoon. The cold front is expected to wash out as it moves into the CWA, having minimal impact on high temperatures though it will bring a drop in dewpoints across Zapata and portions of Starr and Jim Hogg counties. High temperatures are expected to range from the low 90s across the eastern counties to the upper 90s out west today. Winds are expected to become light and variable overnight, which combined with clear skies will allow for efficient radiative cooling. As such, overnight low temperatures are expected to fall to the upper 50s to mid 60s. Gusty southeasterly winds are expected to return Thursday afternoon, with high temperatures returning to the low to mid 90s. Afternoon minimum RH values are expected to range from the mid teens out west, to the 20s across central portions of the CWA, to around 35-40% along the coast today. In spite of the low RH values, fire weather concerns remain somewhat limited today, due to 20 ft winds remaining below 15 mph across most of the CWA. A similar story is expected Thursday, with even lower RH values (10-20%), but 20 ft winds remaining below 15 mph. && .LONG TERM... (Thursday night through Tuesday) Issued at 251 AM CDT Wed Mar 12 2025 A 500mb trough deepens across most of the central CONUS before pushing east, followed by a ridge and the next trough by mid next week. This will generally maintain very dry westerly flow across Deep South Texas through the long term period. At the surface, expect southerly winds turning southwesterly on Friday as a dryline works eastward, setting up a heat spike. A dry front follows on Saturday, with high pressure building into early next week. Have bumped up high temperatures on Friday due to moderate downsloping, mixing in NBM25 and ECMWF guidance, which still may not be warm enough. Triple digit heat will overtake most of the RGV and potentially set multiple record highs. Above normal temperatures generally persist through the remainder of the long term, though not nearly as warm as Friday afternoon. Of more concern this weekend into early next week are fire weather conditions. ERC values across Deep South Texas rapidly approach the 90th percentile by Friday, then launch near or above the 97th percentile and record high values this weekend into early next week. Historically, there is a noticeable increase in wildfire activity when the ERC values reach these heights. Unfortunately, RH values drop into the teens and single digits each afternoon Friday through Sunday, with only gradual improvements Monday into Tuesday. Fuels remain cured and dry to critically dry. The only limiting factor through this stretch is 20 foot wind speeds falling short or just short of Red Flag criteria. In these conditions, Fire Danger Statements and Red Flag Warnings may still be needed, regardless of 20 foot wind speed criteria, for the protection of life and property this weekend into early next week. Fire Weather Watches may be issued as early as tomorrow. Stay tuned and do whatever necessary to avoid open flames or sparks. Additional dry frontal boundaries are on the horizon just beyond the long term, potentially continuing fire weather concerns into late March. && .AVIATION... (06Z TAFS) Issued at 1221 AM CDT Wed Mar 12 2025 VFR conditions are expected to prevail through the TAF period. Winds are expected to remain around 10 kts out of the south overnight, with gusts increasing after sunrise. Gusty winds southerly to southeasterly winds are expected to continue through the afternoon, with gusts diminishing Wednesday evening. Skies are expected to remain clear to mostly clear through the period. && .MARINE... Issued at 251 AM CDT Wed Mar 12 2025 Today through Thursday...Adverse marine conditions are expected to briefly develop this afternoon as winds along the Lower Texas Coast as winds increase to 15-20 kts. Small Craft Should Exercise Cation headlines will likely be needed this afternoon. Winds are expected to decrease overnight, with favorable conditions continuing through the remainder of the short term. Seas are expected to remain light to moderate through the period. Thursday Night through Tuesday...Southerly winds prevail through Friday across coastal waters, before a weak frontal boundary brings northerly winds over the weekend. Early next week, as low pressure deepens into the Plains, expect moderate to strong southerly winds building seas. SCEC conditions are likely offshore Friday into Saturday and again Tuesday. && .FIRE WEATHER... Issued at 251 AM CDT Wed Mar 12 2025 Friday through Tuesday...Energy Release Component values across Deep South Texas rapidly approach the 90th percentile by Friday, then launch near or above the 97th percentile and record high values this weekend into early next week. Relative humidity values drop into the teens and single digits each afternoon Friday through Sunday, with only gradual improvements Monday into Tuesday. Fuels remain cured and dry to critically dry. The only limiting factor through this stretch is 20 foot wind speeds falling short or just short of Red Flag criteria through Monday. In these conditions, Fire Danger Statements and Red Flag Warnings may still be needed, regardless of 20 foot wind speed criteria, for the protection of life and property this weekend into early next week. Fire Weather Watches may be issued as early as tomorrow. Stay tuned and do whatever necessary to avoid open flames or sparks. Additional dry frontal boundaries are on the horizon just beyond the long term, potentially continuing fire weather concerns into late March. && .CLIMATE... Issued at 251 AM CDT Wed Mar 12 2025 High temperatures on Friday may approach or topple record highs for multiple locations in the Rio Grande Valley due to southwesterly downsloping winds. The daily record high in Brownsville for March 14 is 93 degrees. The daily record high in Harlingen for March 14 is 96 degrees. The daily record high in McAllen for March 14 is 104 degrees. The current high temperature forecasts for all three are 96, 99, and 102 respectively. This is on the lower end of some model guidance and model trends, which would bring triple digit heat into Cameron County and topple the McAllen record as well. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 83 65 88 67 / 0 0 0 0 HARLINGEN 89 62 91 65 / 0 0 0 0 MCALLEN 95 64 95 68 / 0 0 0 0 RIO GRANDE CITY 97 59 95 64 / 0 0 0 0 SOUTH PADRE ISLAND 74 63 75 65 / 0 0 0 0 BAYVIEW/PORT ISABEL 83 63 84 65 / 0 0 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...60-BE LONG TERM....56-Hallman AVIATION...60