Monday calm before Tuesday’s storm

Pleasant Monday as Clouds Increase

The weather Monday will be the proverbial calm before the storm as a system over the Gulf of Mexico eyes the Northeastern United States for Tuesday.

Out ahead of this storm system, an area of high pressure off the coast of New England will deliver a pleasant day to the Finger Lakes.

Many areas are starting out with sunshine though a few clouds linger near Lake Ontario.

Gentle south winds on the backside of the high will work with the sunshine to push temperatures into the mid 40s this afternoon.

The sunshine will have to work through some thin clouds during the second half of today. These clouds will announce the pending arrival of Tuesday’s storm system.

The clouds will thicken this evening as temperatures slip back into the mid and upper 30s. Temperatures aloft will remain at or below freezing throughout the day and into the overnight.

A few flurries may develop before midnight, but initially the precipitation may have a hard time working through the dry air to the ground. This evaporating process will help lower temperatures an additional couple of degrees.

Snow Mixing with Rain Tuesday

In my post on Friday, I mentioned two main possibilities for this storm system.

Either the core of heavy precipitation would move overhead along with warm air, resulting in another chilly, moderate rain event. Or, if the storm was further east, the cold air may hold, but the precipitation would be lighter, leading to minor snow accumulations.

The latter scenario seems to be how this storm is unfolding with the western edge of the system impacting Western New York and the Finger Lakes.

With temperatures aloft at or below freezing and surface temperatures in the mid 30s, wet snow is likely for most locations. Some slushy accumulations will occur over higher elevations. Only areas along the shore of Lake Ontario will remain mostly rain.

The rain-snow line on the east side of the storm, where warm air will surge north, will set up over Central New York, but closer to I-88 than I-81.

The precipitation will move in after midnight and persist into Tuesday morning. This precipitation will be light to moderate in intensity. By Noon Tuesday, the widespread precipitation should be over with just some scattered flurries for the afternoon.

The highest snow totals will likely be over the higher elevations of the western Southern Tier with a secondary maximum over the far eastern Finger Lakes, again in the higher elevations. As much as 3 or 4 inches will be possible there. Most mid and low elevation locations will see 1 or 2 inches, with an inch or less across the Northern Finger Lakes.

Roads should mostly remain wet with temperatures above freezing. Lesser traveled higher elevation roads could see slick spots.

Tuesday afternoon, temperatures will push into the upper 30s to near 40 degrees.

With the storm center well to the southeast, winds over the Finger Lakes should top out with gusts of 20-30 mph from the west and northwest.

Lake Effect Wednesday, Second Storm Friday

Cold air will wrap around the storm and intensify over the Finger Lakes. By early Tuesday evening, surface temperatures will drop below freezing while temperatures aloft drop into the single digits.

These temperatures will be prime for lake effect development and maximum snowflake growth.

A band of heavy lake effect snow will develop as a result over Wayne, northern Cayuga, and Onondaga county for Tuesday night and into Wednesday morning. This band is NOT reflected on the above snow map. Locally 4-8 inches could fall between midnight and noon Wednesday.

This band should sag south Wednesday afternoon and dissipate.

Outside the lake effect, Wednesday will be a raw, blustery day. Temperatures will struggle to get much beyond 30 degrees with northwest winds gusting over 30 mph.

High pressure moves overhead Wednesday night. Thursday morning would be frigid if not for a new deck of thin clouds that will move in from the south. Still, teens and low 20s will be widespread Thursday morning.

Thursday will be cloudy but quiet with highs in the mid 30s.

Another storm will move in from the south Thursday night into Friday. This storm too is generating a significant amount of hype and interest.

There does seem to be more potential for moderate snow accumulations on Friday, but the details are still very unclear and the difference between rain and snow razor thin.

It is too early to buy into any single scenario. A mostly rain event is possible as is a heavier 4-8 inch snow. The reality, as is often the case, will probably be somewhere in between.

Stay tuned.