Rochester, NY Area Weather

If you’re reading from anywhere north of 490 right now, how are those partly cloudy skies? For those of us more or less located between 490 and the Thruway, it hasn’t stopped pouring since about 1pm today as strong to severe thunderstorms have been just sitting over the southern third of the county. Over 2″ of rain has officially been reported at the airport.

These thunderstorms are sandwiched between the Lake Erie lake breeze and the Lake Ontario lake breeze. These two colliding breezes show up beautifully on satellite imagery as the low level flow is indicated by the yellow arrows in the image. This convergence in addition to the already warm and soupy airmass already in place, was more than what was needed to get things firing.

As the evening wears on, this area of activity will die down as both lake breezes fizzle out; however, we still have a cold front on our doorstep that may develop more thunderstorms a little later this evening. Could see more strong winds and heavy downpours.

In other news, I’ll be out of town beginning tomorrow morning until Sunday evening so I’ll be unable to update any of the forecasts.

A warm front is currently sitting over the southern fringes of the Twin Tiers region, which has led to some slight instability and a few scattered showers over the course of today. According to the models run at the National Weather Service in Buffalo, the greatest chance of precipitation will be tonight and tomorrow morning, with the spotty convective-type precipitation being the dominant threat. Given the relatively dry, somewhat cooler air compared to the last couple of days, I do find the timing of such precipitation to be somewhat dubious and I’m not at all enthusiastic about the chances of it. (Also consider the fact that the jet stream remains horizontal and zonal, resulting in very little synoptic-level advection.)

Tuesday night into Wednesday: Mostly cloudy. A chance of some scattered showers in a few places, but these will likely be very sporadic. Early lows in the low 60s. Afternoon high temperatures in the upper 70s.

Thursday: Mostly cloudy for the overnight, with clouds breaking and partly sunny skies during the day. Early low temperatures in the upper 50s. Afternoon high temperatures around 80.

Friday through Monday: Rain comes in as the core of a low pressure mass moves across the northern plains and reaches the Twin Tiers on Friday. It will likely continue to bring precipitation through Saturday. The two models seem to disagree over whether or not the bulk of the rain will be on Friday (as the NAM suggests) or if a second wave of precipitation will push through on Saturday night (as the GFS suggests). Either way, the sum total of precipitation should be between 0.5″ and 1.0″. High pressure is expected to push back into the area for Sunday and Monday. In regard to temperatures, they should remain fairly steady, with low temperatures in the low 60s and high temperatures in the low 80s.

Long range: The outlook for July 27-29 looks much like the two days preceding it; high pressure will likely remain in place through that time period and temperatures will likely remain fairly steady.

~J.M. Fuller