Evening Update (8:30pm)
Precipitation is overspreading the Finger Lakes from the southeast this evening. Temperatures are falling into the low 30s as the precipitation intensifies, but remain in the mid and even upper 30s out ahead of the precipitation.
So far, I have seen reports of sleet, freezing rain and rain. Currently, at my house in Groton, it is 33 degrees with rain. A few hours ago, it was 38 degrees.
Temperatures aloft are also hovering near the freezing mark. Cool air continues to attempt to work in from the east while the falling precipitation will also help to cool the air.
Short term computer models seem to have a decent handle on the air aloft and tend to keep temperatures around freezing until tomorrow morning when they drop more substantially. The razor thin margin between snow and mixed precipitation is still at play. Even now, as the storm begins, confidence remains low in how this will unfold.
Please continue to send me updates as to what you are seeing. Please be sure to include your town when reporting.
As a side note, I really wanted to try Facebook Live tonight, but I could not get my feed to cooperate. I may give this another go tomorrow morning.
Stay ahead of the storm with the following useful links:
I continue to monitor the latest trends in the radar, surface temperatures and temperatures aloft. Everything appears to be on track according to this morning’s post, which follows below.
Precipitation should arrive from the south and southeast during the evening hours and will quickly become heavy. I do still think the precipitation will primarily be snow after a little mixing at the onset.
Snow will be heaviest overnight, but several additional inches are possible after sunrise on Tuesday.
Original Post follows:
Precipitation will start to move into the Finger Lakes from the south during the late afternoon and evening hours. This is a bit slower and later than originally expected.
Precipitation should start to become heavy fairly quickly this evening. Heavy precipitation will persist through the night and will slowly taper off Tuesday morning.
Light snow and/or mixed precipitation is likely well into Tuesday afternoon as the storm slowly pulls away.
Precipitation should come to an end Tuesday evening.
Snow Accumulations & Impacts
At this time, the majority of the Finger Lakes is looking at significant snow accumulations. Temperatures throughout the atmosphere are expected to be just cold enough for snow during the majority of this event.
A little mixed precipitation will be possible during the onset of the precipitation, but with the later start time, some areas will see all snow.
The best chance for mixed precipitation will be over lower elevations and for areas further east.
For the Finger Lakes, however, it appears the epicenter of cold and heavy precipitation will set up overhead.
Most areas will see 7 to 12 inches of snow as a result. This will be a very heavy, wet snow. Use extreme caution shoveling, as back injuries and heart attacks can result from overexertion in this type of snow.
The far western Finger Lakes will see lower snow totals due to a shorter time period of heavy precipitation. Areas east of Central New York will see less snow thanks to more mixed precipitation.
There will be some wind with this storm as well, but likely not anything too significant. Top wind gusts of 20 to perhaps 30 mph are possible throughout the storm’s duration.
Temperatures will hover in the low 30s throughout the storm.
Below Normal Forecast Confidence
The forecast confidence remains below normal, despite fairly good agreement among the computer models.
I have mentioned the European model ensembles a number of times over the past week to get a sense of the possible outcomes of this event. Over 90% of the ensemble members now show a very significant snowfall across the area. My snow map above was largely guided by the ensembles.
However, the margin of error for this storm is extremely tight.
If temperatures end up just a degree or two warmer than the models expect, there will be a significant increase in mixed precipitation. This in turn would result in much lighter snow amounts, possibly as low as just a couple of inches.
Therefore, the forecast confidence remains low, as I cannot completely trust the forecast models with such a razor thin cutoff, especially since I have seen a number of similar storms end up warmer than expected.
No two weather events are the same, and the presence of high pressure north of New England, pumping cold air south into the storm, is the difference between this event and other, warmer storms. That is why, despite the lower certainty, I have gone with higher snow amounts.
Stay tuned for updates throughout this winter storm.
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