After some dense fog in many places this morning, high clouds have been filtering in and will keep during so through the afternoon hours. We will keep some clouds around overnight and increase them just a bit for our Wednesday as we again climb into the low 80s. Clouds will then turn overcast on Thursday ahead of our cold front with highs still reaching 80 prior to the front arriving.
There are still two main questions with this front: timing and amount of instability. Models have come into a much better agreement on timing with the front looking to arrive in the late afternoon (around 4pm) to evening (7 to 9pm) for the entire viewing area. Fronts, as we have seen in countless other scenarios, can speed up or slow down, so the timing is not yet set in stone.
The other variable is the amount of instability we will have to work with. Models are also into better agreement that with some warmer temperatures above the surface, there will not be much instability to work with, but storms will be able to overcome that with the amount of life provided by the front and jet stream. One thing that we know for certain is that there is plenty of wind shear with this system. Thunderstorms will likely have their bases low to the ground with the amount of moisture we will have in place, so it should not take much for thunderstorms to be able to rotate. Our main threats with this front are damaging winds, flash flooding, and tornadoes. With the environment in place, strong tornadoes (EF2 to EF5) look unlikely (more information in the next paragraph, but it is a little technical).
(For those of you who are weather enthusiasts, we are looking at a low CAPE/high shear environment, which has been known and shown to produce tornadoes in our region before. In fact, research suggests that low CAPE/high shear environments are the toughest to forecast and often produce tornadoes with little to no advance warning as the storm quickly rotates and produces a tornado.)
The front should clear the area by mid-morning on Friday and we will dry out into the weekend with more seasonal readings. We look to stay dry until the middle of next week when our next cold front will look to arrive.