Special Weather Discussion

Latest Weather Discussion by Kyle Elliott

* meteorological winter to kick off on persistently cold note *

2:00 p.m. Friday, November 28, 2025, Update:

As expected, much colder and drier air arrived just in time for Thanksgiving following Wednesday evening's cold frontal passage, and the overall weather pattern looks quite chilly across the Eastern States in December. A weak Stratospheric Polar Vortex (SPV) and MJO activity in Phase 8 support a persistent trough, or dip in the Jet Stream, and multiple discharges of unseasonably cold air across the Central and Eastern U.S. over the next several weeks (see below). With the cold will come storms, rumors of storms and plenty of hype, but always remember one thing: you can't shovel potential!

In the short term, westerly winds of 15-30 mph with gusts up to 40 mph will continue to buffet northern MD and southeastern PA this afternoon. In addition, high temperatures will be around 10°F below average, or generally in the upper 30s to low 40s. Factor in the strong winds, and wind chills will be stuck in the 20s (see below). Dress in layers and wear a winter coat and gloves this Black Friday! In addition, keep a tight grip on the steering wheel, especially on north-south oriented highways, due to the high crosswinds, and be alert for blowing objects and some minor debris.

An area of high pressure currently centered over the Ohio Valley will shift into the mid-Atlantic States from tonight into Saturday and finally cause winds to subside. However, it will remain unseasonably cold despite mostly sunny skies with highs around 40°F again Saturday afternoon. Low temperatures tonight will bottom out in the mid-to-upper 20s. Clouds will return, lower and thicken Saturday night ahead of an approaching storm system, and a trailing cold front will then sweep through the Commonwealth on Sunday. Light rain and drizzle should overspread the Lower Susquehanna Valley from southwest-to-northeast between ~5-9 AM Sunday morning (see below). Wet snow may occur at the initial onset of precipitation, but I expect no accumulation outside of a thin coating on non-paved surfaces in the South Mountain Range and higher elevations north/west of I-81. The rain won't last particularly long, and it should taper off by the early-to-mid afternoon hours. As a result, rainfall amounts on Sunday should be rather paltry and remain below 0.25" in most spots (see below). Due to the clouds and wet weather, high temperatures will remain at least several degrees below average and only reach the low 40s. The rain will be largely beneficial due to the abnormally dry and moderate drought conditions in place, but you'll need an umbrella, coat and rain gear before heading out the door to Sunday morning church services.

Behind Sunday's cold front, northwesterly winds of 10-20 mph will usher a reinforcing of cold air into the mid-Atlantic States for the start of Meteorological Winter on Monday, December 1st. Low temperatures Sunday night will probably be slightly above average due to partial cloud cover and the northwesterly breeze, but highs on Monday will only end up around 40°F again under partly sunny skies. This push of colder air will then set the stage for the first winter storm of the 2025-2026 season, but details are nebulous at this distance. The storm system will develop over the Deep South from Monday into Monday night and then trek northeastward through the mid-Atlantic States on Tuesday, but its exact track will determine how much, if any, snow falls across northern MD, southeastern PA and the Lower Susquehanna Valley. At this point, the storm track appears too far north for an "all-snow" event, and early-December climatology favors a "mixed precipitation" or "changeover" event with the greatest snowfall accumulations across southern NY and/or northern PA. There won't be any high-latitude blocking present across northeastern Canada or Greenland.. i.e. the North Atlantic Oscillation (NAO) is in its positive phase.. so the system will be moving quickly and not have time to rapidly intensify along the East Coast. Thus, high-end precipitation amounts will be limited by the duration of the event and its intensity. In addition, an upper-level ridge axis will be centered off the West Coast of the U.S. in the eastern Pacific, and this seems too far west for an all-snow event locally. Instead, odds favor a "last-second northward shift" in the system's track that would greatly limit snowfall amounts across south-central PA and increase the probability of a rapid changeover to rain Tuesday morning. It's far too early to speculate about potential snowfall amounts, so check back on Monday for an update and perhaps my first "Storm Outlook Map" of the season! -- Elliott

11:30 a.m. Tuesday, November 25, 2025:

Thanksgiving week kicked off on a dry and pleasant note across the mid-Atlantic States. An area of high pressure over the Commonwealth promoted mostly sunny and seasonable conditions across the Lower Susquehanna Valley on Monday with highs in the low-to-mid 50s. However, clouds moved back into the region last night in advance of a fast-moving disturbance. The relatively weak and disorganized disturbance will zip northeastward through the mid-Atlantic States over the next 18-24 hours and bring periods of generally light rain to northern MD and southeastern PA from this afternoon through tonight. The rain will then taper off from southwest-to-northeast in the pre-dawn hours, and most of the activity should push south/east of the I-95 corridor by 7 AM. The rain may cause some slowdowns on the roads during today's PM commute, but it will be largely beneficial due to the abnormally dry and moderate drought conditions in place. Most areas will receive another 0.30-0.60" of rain from the system (see below).

Broad, southwesterly flow behind tonight's disturbance and in advance of a potent cold front will usher unseasonably warm air into the mid-Atlantic States on Wednesday with high temperatures around 20°F above average. Morning clouds will give way to some afternoon sunshine, and some record highs may even be challenged, tied or broken. At Millersville, temperatures will likely fall just 1-2°F shy of the record high of 69°F from 1979, but it could be tied with enough sunshine (see below). Needless to say, the weather will cooperate and be quite nice for motorists on the busiest travel day of the year. Travel conditions will also be good along most of the I-78, 80, 81, 83, and 95 corridors, and that's just what the doctor ordered! I'm always happy to be the bearer of GOOD NEWS. 🙂

A broken line of showers may accompany the cold frontal passage between ~3-8 PM, but many areas won't receive any rain. In those that do, the wet weather still won't last more than 15-30 minutes. The much bigger story will be the return of significantly colder and drier air behind the front. In its wake, westerly winds of 12-25 mph with gusts up to 40 mph will usher the colder air into the region from Wednesday night into Thursday. Due to the stiff breeze and partial cloud cover, low temperatures will still be slightly above average Wednesday night and generally in the mid-to-upper 30s. Unfortunately, they won't rise much on Thanksgiving Day and.. in stark contrast to Wednesday.. will end up around 5-10°F below average (low 40s). Factor in the blustery conditions, and wind chills will likely be stuck in the upper 20s to low 30s throughout the day (see below). As a result, you'll definitely need a winter coat and gloves before heading out the door to holiday gatherings and Thanksgiving dinner feasts with family/friends, but at least there won't be any threat for rain or snow. I won't promise a lot of sunshine throughout the day, but skies should at least be partly-to-mostly cloudy. Other than having to keep a tight grip on the wheel, there won't be any weather-related issues on the roads this Turkey Day.

The weather on Black Friday will be virtually identical to Thursday. A tight pressure gradient, or difference in pressure, between a storm system over southeastern Canada and high pressure system over the Ohio and Tennessee River Valleys will be the culprit for more strong winds. In fact, westerly wind gusts may be a few miles per hour higher than Thursday and reach 40-45 mph at times. Low temperatures will bottom out around 30°F Thursday night, and highs will only reach the upper 30s to perhaps 40°F on Friday. If you have plans to hit the stores Friday morning for Black Friday deals, dress in layers and be alert for blowing objects and some minor debris on roadways. Overall, the weather should be quite good for travel late this week, but the unseasonably cold and windy conditions will make it feel absolutely miserable outside. Wind chills will only be in the 20s on Friday and may even bottom out in the teens early Friday morning. The aforementioned high pressure system should finally settle into the mid-Atlantic States on Saturday and cause winds to subside. However, the system will be of Canadian origin, so the last weekend of November will kick off on a mostly sunny but chilly note with highs around 40°F. Clouds should then return Saturday night on the backside of the high pressure system, and southerly winds will draw moisture back into the Lower Susquehanna Valley on Sunday. In addition, the next storm system will track from the Central States into the Great Lakes region from Saturday into Sunday, and showers or a period of light rain will likely accompany a trailing cold front later Sunday into Sunday night. Thus, Sunday will probably turn out cloudy, damp and dreary with highs in the 40s, and a reinforcing shot of colder air will likely arrive just in time for the start of meteorological winter on December 1st. I'll leave it there for now, so check back on Black Friday for a brief update. Colder days are right around the corner, but the prospects of accumulating snow are far more uncertain.. -- Elliott