* Mild Start to October - Cooler Mid-month *
* Stormy Pattern Developing, But Limited Cold Air Until After Christmas *

2:00pm Friday:
The next week to ten days will be disappointing for snow lovers. As much as I'd love to have a white Christmas, it's not in the cards this year. Remember, a "white Christmas" (snow on the ground or accumulating snow falling on Christmas day) only happens in Lancaster about twice per decade. Maybe next year...

Lack of snowfall (the next 7 to 10 days) doesn't mean there will be a lack of rainfall--my winter outlook is for above average amounts of both--as a stormy pattern will send two or three rainmakers our way between the 22nd and 28th. Preceding these "wet" events will be a weekend system that will pass well to our south Saturday night--while a few flurries are possible late Saturday night, this system is basically a "miss". Monday into Monday night will bring another southern system our way, but this time it will likely brush us with a period of light mixed precip and cold rain. Timing looks to be about Noon to Midnight Monday with temps hovering in the low to mid 30s.

Tuesday into Wednesday will then turn unseasonably mild as a strong storm cuts to our west and winds up over the Great Lakes. Temps will likely reach 50 degrees here with scattered rain showers at times Tuesday and Wednesday. A cold front will move through Wednesday afternoon with gusty showers, perhaps even a rare December thunderstorm. Christmas Eve and Day will then turn very wind and seasonably cool with temps falling into the 30s and low 40s, but wind chills in the 20s and low 30s. Mountains snow showers will fly to our north and west, however only a flurry or isolated snow shower is likely in Lancaster county Christmas Day or night.

Friday looks partly sunny and seasonable, but another brief warm up is likely next Saturday (mid to upper 40s) as another storm cuts to our west. Some rain showers are possible later Saturday into Sunday as a cold front traverses the region. Some jet stream blocking may develop during the final days of the month, so I'll speculate that cold air may linger for a few days...and just maybe another southern storm will approach with a chance of snow just before year's end. #WhiteNewYear??? --Hörst

  • My Christmas gift for you....a Lancaster Weather Mobile App that I've been developing! It's still rough (called it a "beta" version), but this link should work on most web-enabled smartphone. You should be able to open the link, then save it as an icon on your phone screen.

    2:00pm Thursday:
    Just a quick update today...check back tomorrow for more detail on the rest of the month. Here are five quick hits: 1. A dying system moving east from the Ohio Valley my drop a few flurries tonight, otherwise it's a windy, cold and dry period into the start of the weekend. 2. Saturday night's storm is looking more and more like a "miss" with no sharpening or phasing to bring steady precip north-- at this point we'll be lucky to see even a touch of light snow or flurries. 3. A rain storm looks on the way for early next week...and if it arrives quick enough it could begin a bit of sleet or freezing rain/drizzle on Monday. 4. Tuesday into early Wednesday will then turn milder with temps briefly approaching 50 degrees. 5. Christmas Eve into Christmas day will likely be very windy (gusts possibly >40 mph) with falling temps, perhaps some scattered flurries, and much colder conditions arriving.



    1:00pm Wednesday:
    Remember the Arctic blast that hit here November 13 - 23rd? It's been a month since that Arctic outbreak played out across the region, and since then there's been a total absence of Arctic air here...and, in aggregate, temperatures have been decidedly average (December is running about 1 degree above normal). Meanwhile, an El-Nino-enhanced storm track off the Pacific has come alive (no, El Nino has yet to be officially declared, but its influence is unmistakable to the trained eye) in sending strong storms into the west coast. These systems cross the Rockies, and remnant energy can contribute to storm development over the eastern half of the country. As a result, December has been quite damp (and cloudy) with measurable precipitation falling here on eight of the first sixteen days of December. But with the lack of Arctic air, it's not been very snowy...in fact only 1.1 inches of the white stuff has fallen here so far this month (December's average snowfall is 4.6").

    Going forward, I see a continuation of the stormy pattern into January, and a likely return of some Arctic air in the pattern after Christmas. Until then, however, temperature will continue in the normal to slightly above normal range. In the end, December will likely conclude near-average (+/-2.0° from normal) in terms of temps and above average with regard to total precipitation (rain and melted snow).

    What about day-to-day details? After hitting 50 degrees today, a seasonably cool air mass will take control Thursday through Saturday. Meanwhile, the next is the series of storms off the Pacific will track from CA to the Gulf Coast then likely move quickly off the Carolina coast Saturday night. Such a fast, flat storm track is not ideal for a big snowfall here...in fact, I now see it as a 50-50 chance that this system will have no impact here in Lancaster. Still, there is some uncertainty (until the storm actually forms late Thursday), and so I'll stick with the idea that we may get brushed with some light snow Saturday night (50% chance).

    A trailing southern branch disturbance may brush us late Sunday night or early Monday with some light rain (perhaps mixed with a little sleet), but the trend early next week is for southwest flow to again feed milder air into the region....with another shot at hitting 50 degrees next Tuesday afternoon or early Wednesday. Consequently, the chances of a White Christmas in Lancaster suddenly look rather low. The long-shot hopes for snow lovers to cling onto are: 1. the weekend storm coming to life last minute with a major dumping of snow (10% chance) that can last through milder weather early next week, or 2. a possible Christmas Eve rain storm pulling in cold air fast enough to end as a period of snow on Christmas Day (quite possible in the mountains of PA, but only about a 20% chance in LanCo). --Hörst

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