With a quiet forecast in store for most of Friday, the main area of focus is the upcoming storm system which will make things messy this weekend. There is centainty that the system will affect our area- but questions still exist with the timing of the onset of the storm and the precipitation type.
Here is a look at the Thursday 18Z run of the GFS model...
This model run shows the onset of the storm in our region around 1 AM Sat Morning, with light snow. By 10 AM Saturday morning, the warmer sector of the storm pushes its way northward, allowing for a transition to rain. The rest of Saturday will be rain according to this model, until about 4 AM Sunday morning when cold air ushers into the region behind the surface Low and allows for a chance of light snow.
Here is a look at the Thursday 18Z run of the NAM model...
This model shows the system just barely touching our region around 4 AM Sat morning. Notice the difference between the first panel of the GFS and the NAM. The NAM believes the onset of the storm will be later and will initially fall as a mix- with light snow in areas of S. Ohio and rain/sleet for Kentucky and West Virginia. Moving into the 10 AM hour, the NAM shows a bit of a "hole" in the precipitation over much of West Virginia and eastern Kentucky. The reasoning for this hole is most likely because of the expected downsloping winds. Meaning, winds are expected to have a south-easterly component, and as they blow over the Appalachians and into the lower elevations Northwest of the range, conditions will "dry-out". This downsloping phenomenon has a stronger affect on say Charleston (which is closer to the Appalachians) than Huntington. Notice how the GFS does not show this dry "hole" at the same time period. Lastly, the Nam expects the 4 AM hour on Sunday to bring snow to areas of S. Ohio and Pennsylvania, but rain/sleet mix to most of the tri-state area.
SO.... which is the model to follow and what should we expect? Many of the model runs throughout the day on Thursday were more consistent with the GFS run than the NAM run as far as the timing. We should start to see mixed precipiation by early Saturday morning. Rain throughout the day Saturday is agreed upon in both models; however, will we see downsloping playing a role on restricting rainfall in areas? This is likely to occur. Lastly, will we see snow Sunday? Although the NAM feels it will stay to our North and west, I wouldn't be surprised if we saw a flurry or two. Saturdays nights temperatures will drop below freezing and there should be a good supply of cold moving in on the backside of the Low.
Regardless of what pans out- safe travels this weekend everyone!
Have a great day everyone!