I have been hearing for years, “When is the big one coming”? Well, folks, this pattern is what you have been waiting for years or decades. The biggest major winter storm forecast of my lifetime (I am 23 years old) is approaching us this weekend, bringing major impacts to much of Pennsylvania. Hurricane hunters have flown into the storm system over the Pacific overnight, gathering great data to ingest into model guidance. This has led to a large shift toward a more northerly and amplified storm system.
Feel free to read the scenarios from yesterday here: https://paweatherplus.com/major-winter-storm-scenarios-for-pennsylvania/
If you are here for just snowfall amounts, press “FIRST CALL SNOWFALL AMOUNTS”
CLICK TO JUMP TO THE FOLLOWING:
OVERALL METEOROLOGICAL PATTERN:
The overall pattern from a meteorology perspective is the pattern you look for ahead of intense winter storms. All of the ingredients that meteorologists look for at 500 MB are lining up. A 50/50 low combined with a strong west-based negative NAO block. Additionally, a strong western ridge will allow for the East Coast trough to dig into the southeastern United States. Western Atlantic ridging will allow for the pattern to slow down, and we get a low-pressure system to develop on the East Coast.
With all of the ingredients coming together, this is what will possibly look at the surface. You have your polar jet stream phasing in with the subtropical jet stream, allowing for colder air to phase in with a warm/moist airmass. Arctic Air will be filtering on the East Coast, allowing for major snow and crippling ice storms across much of the country from Texas through the East Coast. This brings us major snowfall here in Pennsylvania!
WINTER WEATHER ROAD CONDITIONS:
VERY HIGH: Widespread snow and/or ice will cover nearly all roadways, including major highways and interstates. Severe winter storm conditions will create extremely dangerous travel. Vehicles may become stranded, especially during the heaviest snow and/or ice. Travel will be impossible at times. Do not travel unless absolutely necessary.
MID-STORM TEMPERATURE:
As stated yesterday, the bad aspect of this storm will be the temperatures. Temperatures during the “worst” part of the storm are currently projected to be in the single digits to lower-teens. Any pre-salting and pretreatment will likely not work at all, and all roadways and interstates will need to be assumed snow-covered. I would not be surprised by very heavy travel restrictions incoming with this storm.
PRELIMINARY TIMING:
Snow will be moving into Pennsylvania southwest-to-northeast Saturday evening through early Sunday morning. Once the storm begins, the conditions will worsen quickly. All day on Sunday will likely have very hazardous to at times impossible travel conditions with bands of heavy snowfall. Snowfall rates of 1 to 2 inches per hour are expected. The snow looks to continue into Monday morning before tapering off Monday afternoon. If you have travel plans Saturday night through Monday morning, it is now time to cancel and reschedule!
FIRST CALL SNOWFALL AMOUNTS:
Even with the fluffier snow expected, I would expect power outages to occur in isolated areas due to the weight of the snow on trees and branches. If you are prone to losing power, prepare for power outages and be prepared to be snowed in. Arctic air will follow this storm system.
AREA A: Preliminary snowfall amounts of 16 to 22 inches. Roadway conditions will likely be impassable Saturday night through early Monday morning with heavy snowfall expected. Schools and businesses will likely remain closed into Monday and Tuesday. In future updates, I will likely need to add a 22+ inch range zone once I become confident where these heavier bands set up.
AREA B: Preliminary snow / sleet amounts of 10 to 16 inches. Roadway conditions will likely be impassable Saturday night through early Monday morning with heavy snowfall expected. Some sleet will mix in Sunday night into Monday morning. Schools and businesses will likely remain closed into Monday and Tuesday.
AREA C: Preliminary snow / sleet amounts of 6 to 10 inches. Roadway conditions with snow and sleet combined will likely lead to very hazardous travel conditions Saturday night through Monday morning. Schools and businesses will likely remain closed on Monday.
WHAT SHOULD YOU DO NOW?
If you’re a snow-lover hoping for the “big one,” excitement is building as guidance continues to show high-end potential with this system.
For those who have travel plans Saturday night through Monday afternoon, it is now time to cancel those plans as travel will likely be very hazardous to impossible at times. Unless it is an emergency, stay home!
If you prefer to wait until the day before to follow the forecast, feel free to scroll on. While changes are still possible, we are increasingly honing in on a higher-end scenario at this time.
I will be on top of it the rest of the week- stay tuned for updates! I will have more updates on the Facebook page!
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-Denys
