Wednesday is your day to prep ahead of Thursdays snow squalls and damaging winds. We will have a detailed write up on these hazards Wednesday by noon. 

After Thursday, its smooth sailing for a while with partly to mostly sunny skies and dry conditions. That said, it will remain cold until Sunday with a MAJOR warm up. We easily could see highs in the 50s!

A strong area of low pressure passing well off to our north on Thursday will send a strong arctic cold front through the region during the morning hours. This will bring a variety of possible weather hazards to our area during the day on Thursday, including high winds, possible snow squalls, and very low wind chills. But we aren't the only ones dealing with this! This storm system will bring high winds, snow, and very cold temperatures to much of the Northeast and northern Mid Atlantic late week.

The biggest issue we will face on Thursday by far is the wind. We expect widespread wind gusts of 40-50mph across the lower elevations, and gusts possibly reaching or even exceeding 50mph in the higher elevations. Locations such as the Catoctin Mountains, northern portions of Parr's Ridge, and much of Washington county could see gusts close to 55mph in isolated locations. Currently, the strongest winds look to be from about 10am until 6pm, though the start time will depend on exactly when the front passes. 

A very tight pressure gradient will set up over the region between the departing cold front/low pressure system, as well as an incoming area of high pressure from the west. This, combined with deem mixing of the lower atmosphere and strong winds aloft, lead to a favorable set up for high winds. Historically speaking, this type of set up has led to some of our higher end wind events with gusts over 50mph. We fully expect that a wind advisory will be issued. 

With this magnitude of winds, some trees and large branches may come down. In addition, there will likely be some power outages, especially across northern MD where the strongest winds are expected to occur. Many homes also are wonderfully decorated for the holidays. If that is you, I strongly encourage you to secure any outdoor decorations as they could easily be blown down or away in wind gusts over 40mph. In areas that see winds gusting over 50mph, we cant rule out an isolated instance of siding or shingle damage, but widespread structural damage is not anticipated. 

A far as snow chances go, they aren't huge, and significant accumulation is not expected. That being said, there is about a 40% chance for snow showers or even snow squalls primarily to the NW of I-95. To the SE of there, temperatures aloft will likely warm enough to keep precipitation as a mix of rain and snow rather than pure snow. 

Across northern MD and southern PA, there could be a few narrow isolated bands of snow showers that last long enough for a light dusting of accumulation. If this occurs, it likely will be confined to the grass, car tops, and decks. However, there is a low, but non zero chance that a snow squall puts down a dusting on the roadways. Again, the chance of that occurring is quite low due to the above freezing temperatues, but its not impossible, and is worth monitoring. The chance for travel/school impacts looks very low at this time. 

Elsewhere across most of central MD south of I-70, no accumulation is expected. 

Finally, the cold. I mean, its going to be a cold day regardless. But when you put 40+mph winds on top of temperatures in the 30s, you get brutally cold wind chills. We start the day with actual temperatures in the mid to upper 30s, but drop into the low 30s once the front passes. Wind chills by early afternoon will likely be dropping into the teens and 20s across the entire area. For those of you headed west, near to even below 0 wind chills are expected across western MD. Lows Thursday night will fall into the 20s with wind chills into the lower teens likely. 

Not much relief is expected on Friday, with highs only making it into the low-mid 30s. And with continued gusty winds, the wind chills will remain in the teens and 20s all day. 

It feels like mid January out there tonight, and very cold low temperatues are expected through much of the upcoming week. It isn't until Thursday where we begin a brief warm up, though much colder temps are expected again after that. 

Regarding the chance for snow on Wednesday, it is dwindling. The chances were never high, but they look even lower now. The best chance for snow showers will be north of I-70. Accumulations look unlikely, though it is still worth monitoring in case minor accumulations occur during the evening rush hour. 

Otherwise, expect a mix of sun and clouds this week with breezy but not overly windy conditions. Winds may increase on Thursday with gusts around 30mph possible, but we expect them to remain below advisory criteria at this time. 

Here is an update on the potential snowfall expected for Friday morning.

Our updated snowfall map calls for a possible dusting for areas NW of I-95. This, if verifies, would only accumulate on the grass and car tops. There will be no accumulation on the roads or sidewalks. For areas north of I-70, especially across the MD/PA state line, the Catoctin Mountains, and southern PA, 1-1.5 inches seems possible, with perhaps an isolated 2" total somewhere. Even here, paved surfaces will likely remain just wet, with accumulation being confined to grass and car tops. We expect no travel impacts to the Friday morning commute. The only exception to this would be up in northwestern Frederick county along the crest of the Catoctin Mountains. Its not out of the question that they stay colder longer, and wind up with 2-4". But that's not an especially likely scenario. If that did occur, some minor slushiness would be possible on especially backroads in that area. 

As far as timing goes, it has been pushed back a touch, starting in southern PA and northern MD between 4am and 7am. Areas along and just south of the I-70 corridor can expect snow to start between 6am and 9am. And if it happens to reach any further south than that, start times would be after 9am.

This will likely be our final call, as we do not anticipate much to change with this winter weather event. However, we will continue to monitor things and update if needed.
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Senior Forecaster Jack

10:36PM 11/18/24 - Lets talk about the chance of winter weather later this week. Its a complex weather system, with multiple types of weather slated to impact our region Wed-Sat.
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WED: The day starts out warm, with a line of showers and embedded thunderstorms moving through between 7pm and 11pm. This line of showers may contain wind gusts between 40mph and 45mph, which could result in isolated minor damage to trees. Severe weather is not expected at this time.

THU: Much colder air arrives behind this line of showers along a strong cold front. By Thursday night, temps will be near or below freezing for areas NW of I-95. Any residual moisture left over as the system pulls away could result in areas of light wintry mix or snow flurries. No accumulation is expected for most areas, however, it wouldn't be shocking to see a very light dusting up in the highest elevations of the Catoctin mountains of Frederick county. Out in Garrett county, significant snow accumulation of 5-10 inches is likely, along with 50mph wind gusts that could lead to blizzard conditions. Winds will gust 30-40mph on Thursday across central MD.

FRI/SAT: There could be some lingering snow showers during the day on Friday, but again, they wont accumulate to anything. Winds both Friday and Saturday will remain very gusty, with gusts between 30 and 40mph, with chilly temperatures as well.

Senior Forecaster Jack

11:45PM 11/17/24 - We have a surprise for you winter lovers towards the end of this weeks forecast!

We know it isn't much, but yes, there is about a 30% chance of a light wintry mix late Thursday night into Friday morning for areas NW of I-95. There remains questions about moisture availability, as its hard to get precip with a westerly wind. But if we do manage to precipitate, the upper low nearby will result in cold enough air for some wintry mix. That said, we do not anticipate any accumulations at this time, and no impacts are expected.

If you want accumulating snow, you'll have to head west, where several inches of snow will accumulate Thur-Sat in portions of Garrett County and the mountains of MD/WV. In fact if current models hold, it would not shock me to see a winter storm watch issued for Garrett County probably on Tuesday as there is very good model agreement in accumulating snow for those areas.

​ Otherwise, expect much colder and blustery weather for the end of the week, which will be much different than the mild and partly sunny conditions for the first half of the week.
Senior Forecaster Jack

Its not a perfect weekend forecast, but we probably shouldn't complain since we finally have some rain in the forecast.

Saturday will be our driest day with highs in the mid 50s to around 60 under partly to mostly sunny skies. There will be an elevated risk for the rapid spread of wildfires, and we expect a special weather statement to be issued to cover this risk. 

Sunday will start out dry, but mostly cloudy. Widespread showers will move in during the afternoon. While they should remain mainly light, a few moderate pockets of rain are possible. Unfortunately, this will only add up to about a third of an inch or less in most places, which will not help our drought situation at all. Rain should clear out Monday morning. 

Senior Forecaster Jack 

For Friday, SPEND TIME OUTSIDE!!! It is going to be absolutely gorgeous with sunny skies, warm temps, and low humidity. It doesn't get any better for late September. By Saturday, it should still be a fairly nice day, but slightly higher humidity, cloud cover, and a chance for evening showers and thunderstorms. An isolated severe storm cant be ruled out, but overall the risk is low due to unfavorable timing and modest severe weather parameters. There wont be thunderstorms everywhere, and its likely that some places don't see any rain. The highest chances are along and west of Route 15, but could extend to the I-95 corridor depending on the timing of the cold front. 

Sunday will be another great day for outdoor activity with mild temps and low humidity, along with partly to mostly sunny skies. Temps continue to remain mild with relatively low humidity through mid week. Each day will feature a low chance for rain, mainly in the evening, but chances overall are low each day. They do increase on Wednesday, with the approach of a weak cold front. No day will be a washout at all, and significant rainfall is not anticipated with plenty of dry time expected. 

Low temps this week will be in the 50s and 60s, so keep those windows open!

Senior Forecaster Jack

On Tuesday, a cold front will stall over northern MD or southern PA during the late afternoon into the overnight hours. Along this front, moisture will pool heavily, meaning any storm that forms along this front will drop a lot of rain in a short period of time. There is uncertainty as to where this front stalls, which will dictate where the storms will stall. If it stalls along the Mason Dixon line, then a corridor of 1-3" rainfall totals (locally as much as 4-6") could occur across northern/northeast MD and southern PA. Right now, I would say the higher chance of this occurring would be north of the state line, and its possible that northern MD doesn't have any issues. However, if the 1-3" rainfall does come to fruition, locally significant flash flooding will  be possible, especially if it occurs over northeast MD where recent days have featured heavy rain. Overall, confidence in this occurring is low, and that's probably why there is no flood watch yet. But it could be a potentially impactful event if it does occur. 

NOTE: The above graphic should say 8/5, not 8/6

There is also a low, but not 0 threat for severe weather with any storms that form on Tuesday. There will be modest amounts of instability, and a LOT of moisture, along with ample forcing from the stationary cold front draped nearby. So, a few of the storms could produce locally damaging winds gusts, or even a brief tornado (although the tornado threat is very very low) right along the front itself where shear will be maximized. The risk of severe weather is low, and SPC only has a marginal risk which is level 1/5. A higher risk will exist further north into central PA where a cluster of possibly severe storms could move through.

The 11pm update from NHC takes the center of Debby east of I-95 and over the eastern shore of MD as a low end weakening tropical depression with sustained winds of 35mph and gusts perhaps to 40mph. But this does not change our messaging or forecast issued earlier on. 

That said, catastrophic flash flooding, damaging winds, and tornadoes will continue to impact portions of the southeast, with potential for over 2 FEET of rain to fall over parts of South Carolina. Please heed all orders given by local officials, and check with the local NWS offices in those areas for specific forecasts.

As far as local impacts, they will be things we have dealt with numerous times before, and are expected to be minimal and primarily beneficial. Lets first start out by saying there is no tornado threat or severe storm threat with Debby, end of conversation. The environment simply does not support severe weather. I have seen WAY too much talk about severe weather in our region and it simply is not true that there is a risk of severe weather here. 

That said, deep tropical moisture along with a relatively slow motion associated with Debby will result in a LOT of rain for our area, with most data and the NWS forecasting a general 4-6" across the area. I think this is a bit bullish, and went with a widespread 3-5" for areas east of Rt.15, and 1-3" west of there. Because of the ongoing drought, and the fact that most of this will fall over 24-48 hours, the flood threat should be pretty minimal. This is still several days out, and some changes are possible depending on the exact track of Debby.

But that being said, some areas have seen significant rains lately, and may see another on Tuesday. So there certainly is at least some potential flash flooding but I don't expect widespread flash flooding. This will likely prompt a flood watch for most of the area. If Tuesdays rainfall is more significant than currently anticipated, then the flooding may be more widespread with Debby. This will however be quite the drought buster, especially if Debby takes a more westerly track which would bring heavier rains further west. It wont completely eliminate the drought, but it will make some big improvements! There wont be any high winds with Debby when she arrives, but some isolated gusts of 30-40mph cant be ruled out in heavier downpours especially east of I-95.

As far as timing, scattered shower and storms are likely at times on Wednesday and Thursday, but neither day look like a washout. Both days will feature a 60% chance of rain. The widespread and heavy rain wont arrive until Friday, lasting much of the day when rain chances rise to 95%. The heaviest currently looks to be from 12pm-midnight Friday. It remains uncertain if rain will last into Saturday, so I'm capping our chances at 60% for now and will adjust as needed. Sunday looks much better. 

NOTE: The above rainfall graphic should say 8/5, not 8/6

Senior Forecaster Jack 

We, along with the brilliant meteorologists at the National Hurricane Center are monitoring an area of possible tropical development east of the Lesser Antilles Islands. Currently, NHC gives this area a 60% chance of developing into at least a tropical depression as it approaches the US East Coast. While its not time to cancel any beach trips yet, I certainly would keep an eye on this over the next 5 days as impacts are POSSIBLE somewhere along the east coast.

Let it be very clear that outside of what I just stated, there is no other known information about this system. It is over a week away from having an impact, if any at all, to the east coast. Could there be an east coast landfalling tropical system? Possibly. But it is entirely possible that this curves and heads out to sea with little to no impact. You are going to see a lot of people posting random model runs showing an unrealistic worst case scenario that will never happen, which they are doing to spread fear and false information. So please, do not listen to anyone who is saying anything other than "keep an eye on the forecast and watch for updates" because we simply (and I mean no one) don't know where this will go IF it even develops. Yep that's right, it hasn't even developed yet so anyone saying otherwise is unfortunately lying to you. 

Senior Forecaster Jack