Wet snow settles over the Northern Plains while storms soak the Texas Gulf coast

Wet snow is forecast to keep falling over the Northern Plains through Tuesday evening, Oct. 27, while easterly flow off the Gulf of Mexico sets off showers and thunderstorms along the western Gulf Coast and across eastern Texas through Wednesday, Oct. 28. The two-sided pattern comes from the National Weather Service’s Weather Prediction Center, which issued its short-range discussion at 3:32 a.m. Eastern time on Oct. 26.

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Two different mechanisms produce the split. A migrating low-pressure system turns the Northern Plains wet and cold, while a separate flow of Gulf moisture keeps the western Gulf Coast and eastern Texas humid and unsettled hundreds of miles to the south.

A low from the Central High Plains drives the snow

Forecaster Ziegenfelder wrote in the Weather Prediction Center’s short-range discussion, valid from 12Z Monday, Oct. 26 to 12Z Wednesday, Oct. 28, that snow would develop over parts of the Northern Plains on Monday. A low-pressure system over the Central High Plains was forecast to move northeastward to the Northern Plains and the Upper Mississippi Valley, and the discussion says the wet snow would continue there through Tuesday evening.

The storm also produces rain. The discussion has it falling over parts of the Northern and Central Plains and into the Upper Mississippi Valley, so the line between rain and wet snow depends on where the cold air sits relative to the track of the low. The discussion does not give snowfall totals for the Northern Plains, and a reader looking for local amounts has to turn to the Weather Prediction Center’s winter weather page, which carries snowfall probability maps for the first three days and thresholds from one inch to 18 inches.

A second piece of the pattern sits farther west. An upper-level trough moves a front eastward toward the Northern and Central Plains, with the front trailing back into the Great Basin by Wednesday. The discussion expects rain and high-elevation snow from the Pacific Northwest to the Great Basin, and snow at higher elevations of the Cascades, the Northern Intermountain region and the Northern Rockies on Monday and Tuesday.

Little flash flooding risk where the snow falls

Precipitation in the north is widespread, but the forecasters who wrote the excessive rainfall discussion issued at 4:14 a.m. Eastern time on Oct. 26 saw little reason for flood concern there. Dolan, the forecaster who signed the first three days, wrote that with little instability the rainfall rates should be moderate at best, and concluded there would be little to no flash flood risk for the area.

The flood risk that the Weather Prediction Center did flag on day one was elsewhere. A Marginal Risk of excessive rainfall covered much of the central and southern High Plains, including West Texas and the Texas Panhandle, where storms could produce locally heavy rain and isolated flash flooding. Marginal Risk is the lowest category of the center’s excessive rainfall outlook, which the page defines as at least a five percent chance of flooding rain within a given area.

Along the dryline, showers and thunderstorms were forecast to develop over the Southern High Plains and ahead of it through Tuesday morning. A dryline marks the boundary between moist Gulf air and the drier desert air to the west, and storms often fire along it in the Southern Plains.

Gulf moisture over Texas builds through the week

For the coast, the short-range discussion points to easterly flow off the Gulf as the trigger. That flow was forecast to produce showers and thunderstorms over parts of the western Gulf Coast and eastern Texas through Wednesday. The text gives no rainfall amounts for those areas, and it separately notes easterly flow off the Atlantic bringing showers and thunderstorms to the Florida east coast and the Keys.

The heavier rain signal appears later in the week. The excessive rainfall discussion kept a Slight Risk on day four, Thursday, Oct. 29, across portions of Texas from the Stockton Plateau through the western Hill Country into south-central Texas. A strong southeasterly low-level jet was forecast to carry moisture out of the Gulf, and the latest model consensus called for 2 to 4 inches of rain, with localized totals of 6 inches or more possible. Day five, Friday, kept a Marginal Risk across Texas, with the forecasters noting it could eventually need an embedded Slight Risk.

The Weather Prediction Center’s extended forecast discussion, issued at 3:17 p.m. Eastern time on Oct. 25 and signed Tate and Miller, tied part of that moisture to Hurricane Vance and expected potentially heavy rain in the Edwards Plateau and south-central Texas. It described rain and storms ramping up across the southern Plains by Thursday, and it said Pacific and Gulf moisture would feed the West later in the week.

By the dates the forecasts give, the sequence is clear even if the totals are not. Wet snow lingers in the north into Tuesday evening, Gulf showers and storms persist through Wednesday, and the more serious Texas rain risk is placed on Thursday and Friday. Each of those calls comes from the Weather Prediction Center’s own text, which is revised on a rolling schedule, so forecasts for later days can shift as new model runs arrive.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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