Severe Weather Threat: The missing ingredient this afternoon

Weather Blog

6:00PM UPDATE: Our best chances at seeing a strong storm develop will be overnight into Thursday from midnight to around 3 am. A cold front pushing through will provide a few passing showers and a possible storm, but once this front passes we significantly lose our much needed storm fuel for anything to really get going. Even though the chances aren’t zero, the odds of anything turning severe once this line gets to our region is very small with most of us seeing merely a few passing showers and sprinkles at best.

5:00PM UPDATE: Little activity is still present over our area. A few small showers have popped up just over Lake Ontario, but they are not much to the eye. Although the storm threat is NOT over yet, the chances of any storms becoming severe will go down as the heat and humidity decrease overnight. Our best chance at seeing storms will be as the cold front pushes through just after midnight bringing a few heavy showers, some wind, and a few rumbles of thunder. Not everyone will see a heavy showers out of this, but this front will be bringing relief from the heat and humidity into Thursday morning.

3:00PM UPDATE: Rochester has hit 90° and oppressive humidity is in place. While it is very hot and humid, only a few fari-weather cumulus clouds have emerged. No significant storm development is expected over the next several hours.

This is the satellite image captured at 3:15pm showing only cumulus fields across Western New York.

2:00PM UPDATE: The setup is prime for storms, but we are still missing a key part – the trigger. We have remnants of tropical system Cristobal, now a strengthening low pressure system to our west creating severe weather for portions of Michigan this afternoon. Meanwhile, us here in Rochester and WNY are currently in the warm sector of a passing warm front bringing in tropical moisture and heat from the south.

With all of this juicy air overhead, the atmosphere is perfectly primed to create thunderstorms. However, there is something missing to the equation that may end up limiting the severe weather threat for the Greater Rochester area through the rest of the day and leaving us simmering in the oppressive heat with little relief until tomorrow.

That key ingredient is a lifting mechanism. In order to set off a thunderstorm there are three KEY ingredients that must be present:

  • Moisture
  • Instability
  • Lift 

We would need a lifting mechanism such as a lake breeze or cold front to trigger a storm. The warm sector is so large that there are no immediate fronts in the area. Temperatures are around 90° and dewpoints are around 70° with significant amount of instability. There is just no lift.

The synoptic, or larger scale flow is providing WNY with a decent and overwhelming southerly breeze which is detrimental to any hopes of a lake breeze developing onshore. The looming cold front out to the west will be our best chances at seeing any storms develop this evening.

The amount of instability, or Convective Available Potential Energy (CAPE) in the air this afternoon is without a doubt present. We like to call this Storm Fuel. This particular model shows a nose of strong Storm Fuel values into later this evening.

The SPC currently has us in a slight risk, which translates to a low risk in seeing a few scattered to isolated severe storms that are strong, but short lived in nature into this evening. The main threat with any developing storm will be high winds and isolated hail.

2:00 PM update: 

So far so good. All is quiet over Rochester as a few showers trek to the east of us, and a stronger line of showers and storms threatens much of Michigan.

Should any storm decide to pop, we will keep up to date with this blog post throughout the course of the afternoon and evening. 

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