Leading Up to Thursday’s Severe Threat
A significant threat for severe weather will exist on Thursday, but today will be a quiet, pleasant day.
Low pressure over the Midwest is pushing a warm front through the Upper Great Lakes. This front will stay well to our west today, leaving us with a mix of sun and clouds. Later in the afternoon, as the front draws closer, thin clouds will start to overtake the sunshine.
Northwest winds will be blustery today, but not as gusty as yesterday. Top gusts should be around 25 mph.
A dry, cooler airmass is in place thanks to those winds with highs today ranging through the 70s and dewpoints only in the 40s and 50s.
The warm front will start to push in tonight, first with showers in the west and then thunderstorms throughout the region. The best chance for thunderstorms will be from about 10 PM to 4 AM. A little small hail or some brief gusty winds will be possible, along with frequent lightning.
Some rain and thunder may linger into the early morning hours, but by the mid-morning, we should see an increase in sunshine as the front clears the region. West and southwest winds will increase with gusts to 40 mph.
These winds will pump heat and humidity back into the region with highs well into the 80s for all but the far northeastern Finger Lakes, where skies may not clear.
The heat and humidity will be accompanied by strong winds aloft, cooling temperatures aloft, and a low pressure system zipping by. These are all favorable ingredients for severe thunderstorms.
Severe Threat Details
Thunderstorms should redevelop tomorrow sometime in the midday or early afternoon hours, starting in the north then working south. Once thunderstorms start to develop, they should quickly strengthen.
Multiple rounds of storms will be possible, starting as cells and small clusters, but possibly organizing into line segments.
Damaging winds and large hail will be the primary threats. There is potential for higher end wind and hail, meaning gusts over 75 mph and hail exceeding 2” in diameter. These are more significant than most severe thunderstorms we see and are a serious threat.
A tornado or two will also be possible, but tornadoes are not the greatest concern tomorrow.
I am also concerned about flash flooding. The storms will be aligned from west-east and will be moving south as a whole. Individual cells may move more easterly along the axis of the storm lines, leading to repeated torrential downpours. Rapid minor to moderate small stream, urban, and gorge flooding could result.
Now, you may read all of that and start to get a bit anxious about tomorrow. Allow me to end with some good news.
The highest threat may end up to our east, where the winds aloft may be stronger at the time of the storms. Currently, the Storm Prediction Center has a little over half of our region in the Level 3 risk classification, while the northwestern portion is in the Level 2 risk and not designated as having a higher risk for the significant wind and hail potential.
While I generally agree with this forecast at this point, given some uncertainties, I could see everything shift further east a bit.
Another reason to be a bit less anxious is you have Finger Lakes Weather. As usual with larger severe threats, I will be live-blogging this event from before it starts throughout its duration. Nowhere else can you get such complete, comprehensive, and interactive coverage. Stick with me tomorrow, and you will know what is coming before it gets there. Please, share Finger Lakes Weather with your family, friends, and neighbors.
Looking to the Weekend
Tomorrow is not the only active weather we will have.
Hurricane Laura will make landfall tonight in western Louisiana. Laura may reach Category 4 status today but should weaken some before hitting land.
Moisture from Laura will press northward late in the week and will begin to supply a new weather system with extra moisture as it dives southeast across the Great Lakes.
The center of the remains of Laura will stay far to our south across the Mid-Atlantic, but this surge of moisture will set us up for heavy rain.
Rain should start sometime Friday night and continue into Saturday. This could end up begin a widespread soaking rain instead of thunderstorms, but that remains to be seen for sure. Rain amounts of 1-2 inches look possible at this point.
If this remains the case and we avoid thunderstorm induced downpours, the rain will be a great benefit to our region while keeping the flood risk low.
A few showers may linger into Sunday, but most of Sunday and Monday will be dry and cooler with highs in the upper 60s and low 70s.
Don’t Miss an Important Update
Keep updated with the latest on the severe weather potential Thursday, and all of the weather in the Finger Lakes. Signing up for email alerts will ensure you always get the latest information — Facebook and other social media channels pick and choose what you see and are thus not reliable for getting the most updated information!