Forecast updated 2:00pm EST - 22 Feb 2011

Our next chance at precipitation this week will come overnight Wednesday in Thursday morning. Looking at the traditional form of the Q-G omega equation, there is not too much vorticity advection present either way but there is some warm air advection throughout most of the state early Thursday morning. Figures 2 and 3 show the Trenberth form of the Q-G omega equation for 1am and 7am Thursday, respectively. There is considerable PVA at the later figure making for rising vertical motion and a good chance at precipitation. Figure 4 shows the Q-vector form of the Q-G omega equation for 30, 36, 42, and 48 hours out, Wednesday into Thursday. These figures further enforce the possibility for precipitation when looking at the convergence present on Thursday morning. Figure 1 shows the approximate freezing line 12Z gfs run for Thursday at 1am EST when this precipitation will be falling. The sounding for Indy at this time show temperatures very close to freezing so this will be a system to watch in the coming day to determine what precipitation type will fall as the temperature could easily fall below freezing.

Short Range Forecast created by Johnny Martin and Talon Atwell

Figure 1

Figure 2: Trenberth 36 hours

Figure 3: Trenberth 42 hours

Figure 4: 4 panel Q vector convergence. Top left is 30hr, top right is 36hr, bottom left is 42hr and bottom right 48hr forecast.