We mentioned a clipper system yesterday in our forecasters discussion that was poised to impact the area tomorrow. Over the last few model cycles, we've seen that system remain relatively constant on modeling, perhaps trending a bit drier, but the shift north to the 2-3" event that we had discussed as a possibility did not occur. As a result, most of the state is in for a light snowfall, with flurries and snow showers in northern and eastern parts of the state to perhaps an inch of fluffy light snow in the southwestern corner of the state. As you can see here on the 4km NAM model, the best QPF is to our south and west because that is where the best forcing aloft is, and as the event attempts to move east, it loses it's energy and intensity as it begins to transfer to a coastal low in the Atlantic which will eventually miss us as it is out to sea by the time it forms into an appreciable storm.
In general, the consensus for this event on guidance is relatively strong re. the amount of QPF that will fall, leaving the wildcard as the snow ratios that we will see for the event. While there is no simple way to forecast ratios, there are a series of computer algorithms which use information from the temperatures throughout the column as well as saturation and information about the snow growth zone to come up with an approximation of what ratios to expect. These algorithms have been consistently outputting ratios around 20:1 for this event, and considering that QPF is more likely to bust a little high than low in my opinion, have taken the modeled QPF and 20:1 ratios for the purposes of this forecast. This results in a general trace to an inch of snow for most of the state, with up to 1.5" or so in far SWCT.
In terms of timing, the event will be relatively short lived, with snow moving into the state during the mid-morning hours to around noontime and moving out by the late afternoon to evening. The morning commute will be fine, and while the evening commute may be a little tricky on secondary roads if an accumulation does fall, overall, impacts from this little event will be relatively minor.
Forecast temps remain on track for highs in the mid 20s. Rest of the forecast from last night remains on track, with the exception of raising the chance of snow showers/squalls on Friday to 50% as guidance has become more amplified with a possible clipper system for that period. We'll have more on that tomorrow or Wednesday if needed.