Today will feature another day of generally quiet weather prevailing across the US as the Nor’easter that brought major impacts to the Northeast is now long gone, and the atmosphere is taking a brief pause before the next system develops off the East Coast early this coming week. The one exception to the generally quiet rule today will be in Arkansas where strong to severe storms are expected to develop today with gusty winds and large hail being the main threats.
The ECMWF’s thunderstorm composite map (what’s that?) provides a good overview of the setup this afternoon. A plume of unstable air will develop as Gulf of Mexico moisture moves north under a strong vertical temperature gradient in the mid levels (steep mid level lapse rates). At the northern edge of this instability plume is a frontal boundary that will help spark storm development this afternoon. As storms grow, they will encounter strong upper level winds (blue arrows). The strong upper level winds will help create abundant wind shear (change in wind speed/direction with height) which will help storms organize into small clusters capable of damaging winds and large hail.
Here’s a loop of the NAM model’s simulated radar forecast showing storms developing along the frontal boundary over NE OK and NW AR this evening, before strengthening as they move southeast towards NW MS. Storms will gradually coalesce into a line which will pose a damaging wind threat for parts of MS and AL before it weakens tomorrow morning. GIF via weathermodels.com.
Track the storms today with GOES-East satellite imagery (IR: https://weather.us/satellite/953-w-320-n/top-alert-superhd-15min.html#play Visible during daylight: https://weather.us/satellite/953-w-320-n/satellite-color-superhd-5min.html#play Satellite tutorial: https://blog.weather.us/satellite-imagery-at-weather-us/) and HD radar (https://weather.us/radar-us/arkansas/reflectivity/KSRX.html#play). Click any map to zoom in for a closer look.
For more information on your local forecast: https://weather.us/
For more information on the local forecast for ME/NH: https://forecasterjack.com/2018/03/10/continued-unsettled-weather-today/