textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 636 PM CDT Tue Mar 10 2026

Key Messages:

* Fire Danger Statement (RFD) remains in effect for Brooks, Jim Hogg, Starr, and Northern Hidalgo counties till 7 PM CDT (see FIRE WEATHER SECTION for more details).

* A Fire Weather Watch has been issued for all of Deep South Texas with the exception of the island on Wednesday from Noon to 8 PM CDT (see FIRE WEATHER SECTION for more details).

* Fire weather concerns are expected to continue through early next week.

* Unseasonably warm temperatures including two heat spikes, one on Wednesday and another on Sunday, is expected to prevail through the forecast period.

* Record to near record-breaking high temperatures are possible on Wednesday and again on Sunday (see CLIMATE SECTION for more details).

* A Small Craft Advisory is in effect for the Laguna Madre and the Gulf Waters till tonight; Marine conditions will be adverse to hazardous at times; Additional Small Craft Advisories may be needed at times through early next week (see MARINE SECTION for more details).

DISCUSSION

Issued at 302 PM CDT Tue Mar 10 2026

The main weather concerns through the forecast period will be 1) the windy conditions and borderline fire weather concerns for today, 2) the elevated to critical fire weather conditions on Wednesday, 3) the potential for record to near record breaking heat on Wednesday and again on Sunday, and 4) additional fire weather concerns Wednesday through next weekend.

The latest GOES-19 visible satellite imagery and sfc observations depicted a FEW-SCT strato-cumulus clouds with a few high level cirrus clouds overlaid on top of the lower strato-cumulus deck this afternoon. Expect for these cloud trends to continue throughout the day today. An enhanced pressure gradient, courtesy of a low pressure system and shortwave trough over the Sierra Madre and a 1021 mb sfc high presssure system over Florida and the Gulf Waters, coupled with a strong H850 low level jet (LLJ) with winds between 25-40 kts, and increasing mixing heights this afternoon, and local topographic effects have effectively activated the "Valley Wind Machine" today. Strong south-southeasterly winds 20-35 mph with peak gusts ranging between 40-45 mph will prevail through today, specifically over Cameron, Hidalgo, and Willacy counties. That is where we have a WIND ADVISORY in effect for till 7PM CDT this evening. Later this evening/tonight, winds are expected to wane some, but still remain elevated as the LLJ winds remain strong and mixing heights decease with sustained winds between 10-20 mph.

In addition to the windy conditions today, there is a borderline fire weather threat today as well as relative humidity values are expected to drop some this afternoon. We decided to issue a Fire Danger Statement (RFD) from 2-7 PM CDT for Brooks, Jim Hogg, Starr, and Northern Hidalgo counties due to the combination of relative humidity values getting close enough to criteria (i.e. between 35- 40%), the breezy winds, the fact that those areas are either under Extreme (D3) to Exceptional (D4) Drought conditions, and the Texas A&M Forest Service has our CWA under a High Fire Danger Risk for today.

Mid to upper level energies/shortwaves associated with the main parent trough that will be tracking across the state of Texas will yield a slight chance for a rain shower or two (20-30% PoPs) across our western sectors (i.e. areas west of IH-69C) later this evening/tonight. Most of the rain will be confined to our north across central and south Texas where the stronger forcings, jet dynamics, and instability values will be in place. Otherwise, expect for rain-free conditions to persist through tonight and for that matter through early next week.

During the day on Wednesday, a cool front and dryline is expected to pass through Deep South Texas and the Rio Grande Valley from west to east. A precipitous drop off in dewpoint and relative humidity (RH) values are expected to unfold following the dryline passage. South- southwest winds will shift out of the northwest 10-20 mph with gusts as high as 25 mph or so. The combination of low RH values between 15- 30% across the area along with dry antecedent conditions with D2 (Severe Drought) to D4 (Exceptional Drought), increasing mixing heights likely tapping into even drier air, and at times breezy northwesterly winds will result in an elevated to critical risk for fire danger on Wednesday. As a result, we have issued a Fire Weather Watch for all of Deep South Texas with the exception of the island from Noon to 8 PM CDT Wednesday (see FIRE WEATHER SECTION for more details). The Texas A&M Forest Service has placed much of Deep South Texas under a Moderate Fire Danger Risk with a pocket of High Fire Danger Risk over northern Zapata and Jim Hogg, and another pocket of High across the Lower Valley (i.e. Cameron, Willacy counties into the barrier island) for Wednesday.

In addition to the elevated to critical fire risk for Wednesday, compressional heating following the passage of the dryline will increase during the afternoon hours on Wednesday, courtesy of some downsloping off the Sierra Madre from west-northwest winds. This will result in a heat spike taking place on Wednesday. Record to near record-breaking temperatures are expected on Wednesday with high temperatures topping out in the 90s across the region with mid to upper 90s along the Rio Grande Valley (see CLIMATE SECTION for more details).

Each day through the early parts of next week, fire weather concerns will remain in play as there will be yet another, potentially strong cool front that pushes through the region Sunday night into Monday (see FIRE WEATHER SECTION).

Unseasonably warm temperatures that includes two heat spikes will prevail through the forecast period or through early next week. The first heat spike will occur on Wednesday as highlighted above. The second heat spike is progged to take place on Sunday ahead of another cool front. On Sunday, record to near record highs will be possible once again with high temperatures topping out in the mid 90s to lower 100s most places.

AVIATION

(00Z TAFS) Issued at 636 PM CDT Tue Mar 10 2026

VFR conditions are forecast to continue this evening, with MVFR ceilings forecast to develop overnight. Gusty southeasterly winds will continue this evening with wind gusts diminishing around midnight. Winds will likely begin to shift westerly to northwesterly around sunrise as a weak cold front moves through the area. Skies will likely begin to clear by mid-morning with VFR conditions continuing through the remainder of the period.

MARINE

Issued at 302 PM CDT Tue Mar 10 2026

Courtesy of strong southerly winds 15 to 25 knots gusting up to 30 knots, we've decided to issue a Small Craft Advisory for the Laguna Madre and the Gulf Waters through this evening/tonight. The Small Craft Advisory is in effect till 1 AM CDT Wednesday for the Laguna Madre and the Nearshore Waters, and till 7 AM CDT Wednesday for the Offshore Waters. On Wednesday, Small Craft Exercise Caution (SCEC) conditions will take place over the Bay and Gulf Waters. Following the cool fropa and dryline, hazardous marine conditions are expected to develop late Wednesday night through Thursday. A Small Craft Advisory (SCA) is possible during this time. Marine conditions improve Thursday night through Saturday night with a return to low to moderate winds and seas. Adverse to hazardous marine conditons return Sunday through the early parts of next week in response to a second cool fropa. Small Craft Exercise Caution (SCEC) to Small Craft Advisory (SCA) conditions are possible during that timeframe.

FIRE WEATHER

Issued at 302 PM CDT Tue Mar 10 2026

Today, there is a borderline fire weather threat today as well as relative humidity values are expected to drop some this afternoon. We decided to issue a Fire Danger Statement (RFD) from 2-7 PM CDT for Brooks, Jim Hogg, Starr, and Northern Hidalgo counties due to the combination of relative humidity values getting close enough to criteria (i.e. between 35-40%), the breezy winds, the fact that those areas are either under Extreme (D3) to Exceptional (D4) Drought conditions, and the Texas A&M Forest Service has our CWA under a High Fire Danger Risk for today.

During the day on Wednesday, a cool front and dryline is expected to pass through Deep South Texas and the Rio Grande Valley from west to east. A precipitous drop off in dewpoint and relative humidity (RH) values are expected to unfold following the dryline passage. South- southwest winds will shift out of the northwest 10-20 mph with gusts as high as 25 mph or so. The combination of low RH values between 15- 30% across the area combined with dry antecedent conditions with D2 (Severe Drought) to D4 (Exceptional Drought), increasing mixing heights likely tapping into even drier air and at times breezy northwesterly winds will result in an elevated to critical risk for fire danger on Wednesday. As a result, we have issued a Fire Weather Watch for all of Deep South Texas with the exception of the island from Noon to 8 PM CDT Wednesday (see FIRE WEATHER SECTION for more details). The Texas A&M Forest Service has placed much of Deep South Texas under a Moderate Fire Danger Risk with a pocket of High Fire Danger Risk over northern Zapata and Jim Hogg, and another pocket of High across the Lower Valley (i.e. Cameron, Willacy counties into the barrier island) for Wednesday.

Each day through the early parts of next week, fire weather concerns will remain in play due to continued low relative humidity levels and at times breezy conditions, and yet another, potentially strong cool fropa through the region Sunday night into Monday.

CLIMATE

Issued at 302 PM CDT Tue Mar 10 2026

Strong compressional heating from west-northwest downsloping winds in response to a dryline passage will result in a surge in temps during the afternoon hours on Wednesday. Record to near record- breaking temperatures are likely on Wednesday with high temps topping out in the 90s most places (mid to upper 90s along the Rio Grande Valley).

Record High Temperatures for March 11:

* Brownsville: 95F degrees (2018) * Harlingen: 97F degrees (2018) * McAllen: 101F degrees (2018)

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 72 94 64 76 / 10 10 0 0 HARLINGEN 70 95 57 77 / 10 0 0 0 MCALLEN 73 96 61 81 / 10 0 0 0 RIO GRANDE CITY 68 94 61 79 / 20 0 0 0 SOUTH PADRE ISLAND 72 84 64 71 / 10 10 0 0 BAYVIEW/PORT ISABEL 70 92 61 74 / 10 10 0 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...Fire Weather Watch from Wednesday afternoon through Wednesday evening for TXZ248>255-351-353>355.

Wind Advisory until 7 PM CDT this evening for TXZ253>255-353>355.

GM...Small Craft Advisory until 1 AM CDT Wednesday for GMZ130-132-135- 150-155.

Small Craft Advisory until 7 AM CDT Wednesday for GMZ170-175.