For the past couple of weeks, Josh and I have been mentioning about what we thought would be the first legitimate shot of a Winter storm to hit the area this season, during the upcoming week. Fortunately for us, as we near closer to the time period, a storm does appear to be likely. Unfortunately, the impacts will be felt beginning Monday, December 28th through the 29th. A lot of you will be traveling during this period, so it is vital that you relay this information to family and friends whom you know are traveling.
The last time we brought you information regarding this storm, it looked like we would be spared the worst of it, and receive a mainly rain event. However, over the course of today, models are indicating a colder scenario, thanks to a significant high pressure to our North that will help funnel cold air into our region. As the low pressure from the southwest cuts into the Great Lakes, it will push the cold air out of the region. Depending on how long the cold air is able to last, will determine exactly how much frozen precipitation our area sees.
First off, Today’s 12z GFS:
The above image is valid this upcoming Monday, during the afternoon. Anywhere in the pink indicates ice. This would be a bad scenario for those who live in North Central PA, North Eastern PA and points north. This area would see significant icing verbatim..if this MODEL is correct. Not a forecast.
As we advance the GFS forward 12 hours, the pink transitions into snowfall as it heads northeast thanks to there being colder air in place. Notice the high pressure sitting near the border of Maine. IF that high pressure was just 50 to 100 miles further southwest, Northern sections of PA would see a much longer period of icing.
Even on this run of the GFS, it is still an all rain event roughly I-80 south. And as the cold air escapes the area, we all turn to rain. My fear is that the cold air does not escape so quickly, which would lead to a significant ice storm for high elevations through Central PA, and all of Northern PA…but that would probably be the worse case scenario.
This afternoon’s Euro run:
Even though this looks vastly different than the GFS, it is not. This is simply because I used two different websites for the individual model output. Even the European model, (statistically the most accurate), is painting colder scenario than it previously had. Notice the dark blue 32 degree line. Anywhere north of that is either seeing freezing rain, sleet, or snow. This would include nearly the exact same locations the GFS showed…North Central PA and Northeastern PA. The rest of us just see a rain event verbatim.
The European Ensemble guidance suggests the colder scenario as well. For those who have no idea what I am talking about, The Euro Ensemble guidance is essentially the same model ran 52 ways with slightly altered data to get a “mean consensus.” Out of the 52, several of them even show snow as far south as the PA/MD border. While half of them show a significant icing event for the Northern Tier of PA. And of course there are several that are just plain rain scenarios for everyone.
Summary: A significant ice storm is possible for areas I-80 North in PA between Monday, the 28th and Tuesday, the 29th, of next week. Please be aware if you are traveling during this time-frame, as this could create big time impacts.
Here is the way we see it region by region breakdown:
Southeastern PA: All rain: 95% chance. Ice: 5% chance.
South Central PA: All rain: 80% chance. Ice: 15% chance. Snow: 5%.
Southwestern PA: All rain: 99% chance. Ice: 1% chance.
Northwestern PA: All rain: 80% chance. Ice: 15% chance. Snow: 5%
North Central PA: All rain: 50% chance. Ice: 40% chance. Snow: 10%
Northeastern PA: All rain: 50% chance. Ice: 40% chance. Snow: 10%.
**These percentages are based off how likely the precipitation is to occur.**
As of this evening, Josh and I are still favoring an all rain event for all of PA. However, the odds are continuing to increase for a frozen mix for at least the Northern Third of Pennsylvania. This will be an interesting storm to track. Again, a lot of you are traveling, share the word, start thinking about plan B just in case..to stay ahead of the storm please have our Facebook page liked if you haven’t already —> https://www.facebook.com/newxaction/?fref=ts
-Chris
You must be logged in to post a comment.