Winds are already gusting to 50-60 mph across the region, and it will be getting even stronger as we head into the afternoon! Gusts of 60-70 mph are possible, and could even reach hurricane force (74+ mph)! Wind speeds of 58+ mph is the minimum reading for a thunderstorm to be considered severe. BWI has already hit wind speeds of 55 mph today, with DCA and IAD just a few mph weaker.
Here’s a crash course in how to determine the strongest wind gusts:
You can use forecast soundings if you want… I have IAD’s sounding from this morning since we’re in nowcast territory.
Here’s the sounding, with the mixing layer labeled:
In dry air, the mixing layer is a volume of air that has temperatures that cool dry-adiabatically (a rate of 9.8 C/km) as you go up. Air is free to mix within this layer, and it is where the wind can blow uninhibited from the top of the layer to the bottom of the layer. The strongest winds in this layer indicates the maximum wind possible. A mixing layer can either be at the surface or aloft.
The wind barbs on the right indicate the winds at certain levels… the lines and flags indicate the wind speed in knots. Winds of ~65 kts are shown at the top of the mixing layer. More information on deciphering the winds barbs: LINK
Granted, this is just the 12z (7am EST) sounding… as the sun warms the atmosphere, the mixing layer will likely go higher up and we could see those stronger winds in the mixing layer this afternoon.