Old Res Weather
Lexington, Massachusetts, USA
35°F
2/16/2025 7:17pm
- Clear
-
35.1°F / 1.7°C
-
32.4°F
- 90%
- Calm, 10-min avg: Calm, gust: None
-
- 10 miles
- 0.01 in
- $VPuv None
National Short Range Forecast Discussion
Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 248 PM EDT Thu Aug 13 2026 Valid 00Z Fri Aug 14 2026 - 00Z Sun Aug 16 2026 ...Dangerous heat continues from the Central/Southern Plains to the Southeast... ...An active pattern will keep the threat of heavy rainfall/flash flooding in the forecast throughout much of the Midwest and Western U.S... A burgeoning heatwave continues across much of the southern U.S. from the central/southern Plains east through the Middle/Lower Mississippi Valley and into the Southeast as an upper-level ridge builds over the region. Forecast highs in the upper 90s to low 100s along with high Summer-time humidity in place will lead to heat indices in the 105 to 115 degree range. Some record-tying/breaking highs will be possible as many areas see their hottest temperatures of the year so far, or even in the past few years in some cases. Low temperatures only dropping into the mid-70s to low 80s will provide little relief from the heat overnight. These factors have contributed to widespread areas of Major to Extreme levels of HeatRisk (levels 3 and 4 out of 4), indicating a level of heat dangerous to anyone without access to adequate air conditioning or hydration. Unfortunately, the heatwave looks to continue well beyond the current forecast period through at least mid-August. Meanwhile, areas of scattered to widespread thunderstorms within the stronger upper-flow rounding the ridge continue to bring a heavy rain/flash flooding and severe weather threat. One such region is across the Midwest from the Middle Missouri/Upper Mississippi Valley southeast into the Ohio Valley and central/southern Appalachians. Repeated rounds of heavy rainfall leading to saturated soils and ongoing flooding have prompted a Moderate Risk of Excessive Rainfall (level 3/4) across portions of central to southeastern Indiana through this evening/tonight (Thursday) as scattered to widespread flash flooding will remain a threat. Additionally, the Storm Prediction Center has noted a Slight Risk for severe weather (level 2/5) as some storms may produce damaging winds or an isolated tornado. A much broader Slight Risk of Excessive Rainfall (level 2/4) covers the rest of the region in general for more scattered, possibly locally significant instances of flash flooding. Another Moderate Risk has now been issued for portions of south-central to southeastern Iowa and northwestern Illinois for Friday where additional scattered to widespread and possibly significant instances of flash flooding can be expected, with another broad Slight Risk in place across the region. A more focused Slight Risk is in place from the Upper Mississippi Valley into the southern Great Lakes region Saturday as the storm track shifts a bit north. To the west, additional areas of storms with a heavy rainfall/flash flood threat are also expected through the Interior West and into the High Plains within the southwesterly flow along the western side of the upper-ridge. The greatest storm coverage and relative highest influx of moisture rounding the upper-ridge will vary day-to-day as the flow adjusts ahead of an upper-trough moving into the Northwest. However, at least isolated heavy downpours/flash flooding can be expected throughout the region through the next couple of days. Through this evening, the greatest threat is expected across portions of the central/southern High Plains as well as across portions of the Southwest and Great Basin, where Slight Risks are in effect for scattered instances of flash flooding. For Friday, the greatest threat will concentrate along the central High Plains as well as across portions of the Southwest, with additional Slight Risks in effect. A Slight Risk continues for the central High Plains on Saturday while the storm threat looks to decrease across the Great Basin/Southwest and into the northern High Plains. Elsewhere, daily rounds of scattered thunderstorms are forecast from the Mid-Atlantic and into the Southeast and Florida. Temperature-wise, conditions will be around to below average and more mild for most of the country away from the heat wave over the southern U.S. Forecast highs generally range in the 70s and 80s from the Northeast west through the Great Lakes, Northern Plains, and into the Interior West outside of the Deserts, where highs into the 90s and low/mid-100s will be hotter but still below average. Portions of the northern High Plains as well as much of the West Coast will see the relatively coolest temperatures, with highs only into the 60s. Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php