Kerr County faces stubborn heat, then a shot at the season’s first widespread rain

Kerr County will stay hot into early next week before forecasters say a complex weather pattern — one that could pull in moisture from a record-setting Pacific hurricane — brings the best chance for widespread rain the region has seen since summer.

The National Weather Service’s Austin/San Antonio office said in its Friday forecast discussion that a ridge of high pressure will shift south enough by early next week to produce northwesterly flow aloft, but temperatures will stay “stubbornly and unseasonably hot” as that airflow keeps drawing from a warm air mass over the Mexican plateau. The shift does open the door to isolated storms over the southern Edwards Plateau and Hill Country on Sunday and Monday afternoons and evenings, though forecasters put those chances below 20%.

The bigger story, meteorologists say, is a trough forecast to move across the southwestern United States and Intermountain West on Tuesday and reach Central Texas by midweek. How much rain that trough delivers to Kerr County depends heavily on its interaction with Hurricane Polo, one of the strongest hurricanes ever recorded in the Eastern Pacific.

A historic hurricane, and its moisture, in play

Polo intensified from a tropical storm to a Category 5 hurricane in about 24 hours last week — the second-fastest such strengthening on record, behind only Hurricane Patricia in 2015 — and reached a central pressure low enough to rank among the most intense tropical cyclones ever observed in the basin.

In a Friday afternoon advisory, the National Hurricane Center said Polo remains a powerful Category 5 storm, with an initial intensity of about 178 mph and a central pressure of 913 millibars, based on data gathered by a NOAA research aircraft and a drone it launched into the storm. Forecasters said Polo is expected to turn northwestward, then northward through the weekend, before an approaching trough steers it northeast toward Baja California Sur early next week. Some weakening is expected as the hurricane moves over cooler water, but it’s forecast to remain a major hurricane through the weekend.

Critically for Kerr County’s forecast, the Hurricane Center confirmed the connection local forecasters have been watching: “Distant moisture from Hurricane Polo and Odalys will be transported into the southwestern United States this weekend and early next week, and may indirectly contribute to a heavy rainfall and flash flood threat in the region.”

What it means for Kerr County

The NWS said the overall pattern favors rain, with chances for widespread rain in Central Texas starting as early as Tuesday and continuing into Friday of next week. But the agency cautioned that most forecast models suggest the bulk of any rain would likely fall on just one or two days within that window, rather than spread evenly across it.

The trough is also expected to drag a Pacific cold front into the region — the first notable front of the fall — which could push highs down to near normal, potentially into the 80s, by the latter half of next week.

Both the local weather service office and the Hurricane Center flagged the same source of uncertainty: model guidance disagrees on how fast the trough will move, which determines how much of Polo’s tropical moisture gets pulled into Texas versus staying farther west. The Hurricane Center said its own forecast confidence had dropped for days three and beyond because of that growing model spread.

Forecasters are urging residents to watch for updates as the pattern comes into sharper focus over the weekend.