A piece of it has already produced flooding in Southern California and Las Vegas. Another piece has led to freezing rain on roads in North Texas. That’s pretty impressive for a storm system already.
Soon it will get the chance to pick up moisture from the Gulf of Mexico. That adds up to a big, wet storm moving our way next week.
That’s the easy part.
Sometimes the biggest storms are the easiest ones to forecast. Lots of moisture; a large area affected; cold in advance and behind the storm. But, as usual, it’s the details that make forecasting tricky.
Here’s what we’re most sure about:
- The Arctic blast this weekend. Temperatures by Sunday will only reach the mid-30’s….nearly 20-degrees below "normal."
- Strong winds Sunday, gusting to 40 mph, dropping the wind chill to single digits by Sunday night
- A large, fast-moving area of rain moving from the Gulf of Mexico all the way up the East Coast. Heavy rain at times.
- Another cold blast after the storm, leading to a very cold and windy Thanksgiving Day.
- Lots of travel troubles for those going west through Pa. or north into New England
Here’s what’s still in question:
- Exact timing on when precipitation starts on late Tuesday.
- If it will start as a wintry mix in the northern and western suburbs.
- How far west precipitation will reach. The farther west, the higher the chance of snow.
- Speaking of snow, how much? And how far east?
Because there is no blocking pattern in the atmosphere, the storm will move very quickly, which will limit the amount of snow that would fall. That’s different than a typical early-season storm.
We usually see a strong, slow-moving upper-air low moving right across our area.
The only reason for the snow threat this time is the unseasonable chill ahead and behind the storm.
It is still about five days until we feel the brunt of the storm. Especially early in the season, with nearby ocean temperatures near 50-degrees, predicting snow amounts would be foolhardy.
It certainly looks like the best chance of accumulating snow in our area is in the Poconos, with other areas well N&W of Philadelphia (especially in higher elevations) having the next best chance. The lowest chances are at the Jersey Shore & Delaware Beaches.
We should know more of the details each day as the busy travel times approach.