Monday Rain Chances: Why Forecast Models Still Disagree on Rainfall Totals

After a dry and warm weekend across Rowan, Davie, and Davidson Counties, attention will begin shifting toward Monday — which is expected to become our next best opportunity for accumulating rainfall across the area.

While confidence is growing that showers will develop as a cold front moves through the Carolinas, there is still noticeable disagreement among forecast models regarding just how much rain we could actually receive.

What The Latest Models Are Showing

The latest NAM model has trended noticeably wetter with Monday’s system, showing rainfall totals in the range of:

• Around 0.50” to 0.75” across portions of the area

Meanwhile, the latest Blend of Models guidance — which combines multiple forecast models together — remains much lighter, generally showing:

• Around 0.10” to 0.25” of rainfall

That is a fairly large spread in rainfall expectations for a system that is only about a day away.

Why Is There So Much Disagreement?

The biggest reason comes down to moisture availability and storm coverage.

This system does not have a strong connection to Gulf moisture, which means rainfall totals will depend heavily on:

• How efficiently moisture can move northward ahead of the cold front
• Whether showers become more widespread or stay scattered
• How long rainfall can persist over the same areas

The NAM model is handling the atmosphere as slightly more moisture-rich and unstable Monday afternoon. That allows it to generate more widespread showers and locally heavier rainfall totals.

The Blend of Models, however, is leaning toward a faster-moving and less organized setup where showers remain more scattered and lighter overall.

Another Important Factor: Timing

Timing differences are also playing a role.

Some guidance pushes the cold front through the area more quickly Monday afternoon, limiting the amount of time showers can develop. Other models slow the front down slightly, allowing rain to linger longer and totals to increase.

Even small timing differences of just a few hours can dramatically impact rainfall totals in setups like this.

What Looks Most Likely Right Now?

At this point, the most reasonable forecast likely falls somewhere in between the wetter NAM solution and the drier blended guidance.

Current expectations:

• Most areas likely receive measurable rainfall
• Widespread heavy rainfall still appears unlikely
• Localized heavier pockets could occur if thunderstorms develop Monday afternoon

For now, rainfall totals averaging:

• Around 0.25” to 0.50”

appear to be a reasonable middle-ground forecast, though adjustments are still possible as newer model data arrives through Sunday.

Severe Weather Threat Remains Low

A few thunderstorms will be possible Monday afternoon and evening, but the overall severe weather threat currently remains low.

Better instability and stronger severe weather parameters are expected to remain farther south and east of the area.

Cooler Air Returns Tuesday

Behind the cold front, cooler and drier air returns Tuesday with sunshine and highs falling back closer to 70 degrees across the region.