What Kenny said.
Things that generate a SW flow:
Approaching cold front from the West or NW (occluded fronts considerably weaker)
Approaching short wave (like a mini cold front with kinks in the pressure gradient)
Approaching low pressure from the West
A S or SW Jet Stream coupled clear down to the Surface (mostly happens in Spring and Fall)
Things that kill DC wind.
Monsoonal flow (like Kenny said)
Mosisture in general, though a T-Head wedged at Temp can make it go off just as easily
Temp diffs of less than 20 degrees day to night (like Kenny said)
Fronts which approach from the East (not typical but it does happen)
HIgh pressure over the area in Summer (dead air)
Timing on frontal passage, Strong approaching fronts tend to make the the wind very squirrley after the prevailing winds switch North.
Plus a dozen or so other attributes that make the weather oh, so chaotic.
-Craig
Don Losee wrote:Craig
I am trying to get sharper at weather watching. I have some pretty good training. Flight School. What did you see at DC that made you call the blow today? It was blowing good until 5:30. What are the key factors at DC?
Capt. Don