Weather Briefing: Friday, February 16th, 2018

HIGHLIGHTS: Cooler for the weekend, then warm and unsettled next week.

Over the past few days, our area has seen unseasonably warm temperatures for February, making things feel more like the middle of May. These warm temperatures will continue on Friday until a frontal boundary moving into our area from the northwest brings a shot of cooler air that should make its way into our area by Friday night into Saturday morning. Temperatures on Saturday will likely be 25-35 degrees cooler than temperatures on Friday, as high pressure in the Northeastern United States will move cold air down into our region. This cold air, which is too dense to be forced over the mountains, tends to pool along and immediately to the east of the Appalachian Mountains, creating a phenomenon called Cold-Air Damming. This type of setup will be the main driver of the cooler temperatures for Saturday, and will likely remain over our area into late Saturday night, as no obvious source of heating looks likely to erode the cold air near the surface. At the same time that the cold air becomes locked in place, precipitation will form along the now-stationary frontal boundary, creating what will more than likely be a cold rain for Saturday afternoon. On Sunday, the precipitation should move out of the area by the early morning hours, leaving us with what should be both a sunny and seasonable day.

 Image depicting the Cold-Air Damming Setup for Saturday.

Image depicting the Cold-Air Damming Setup for Saturday.

Looking ahead to next week, computer models are hinting at another possible cold-air damming event for Monday that could keep high temperatures lower than would be suggested by the upper-level flow pattern, which will see building areas of high pressure over the Southeastern United States and Eastern North Atlantic Ocean. This ridge of high pressure, which will strengthen throughout the early-to-middle part of next week, will allow for a warm, southerly flow to develop throughout the southeast, likely setting up another unseasonably warm week of temperatures. Additionally, this "dome" of high pressure could force much of the precipitation associated with various low pressure systems up to our west and north. On the image below, the red dashed lines serve almost like train tracks that disturbances follow. As you can see, the ridge to our southeast is blocking any significant low pressure disturbances from entering our area. Nevertheless, instability created by the warm and humid flow is likely to kick off some showers during the week next week, so some precipitation is still possible, although the heaviest of the moisture looks to remain to our north and west. However, if the forecasted position of this "dome" changes, we could be in for another soggy week next week.

 Synoptic Setup for the middle of next week

Synoptic Setup for the middle of next week

Have a great Friday and a wonderful weekend!

Chase Scott Graham