Tuesday, December 10th, 10PM

No changes for the overnight.  Rain is changing to snow in northern Carroll and Frederick counties, eventually in all areas over night.  A coating to a couple of inches mainly on grassy surfaces expected with temperatures falling to near or below freezing for most areas along and west of 95 by early morning.  Some heavier banding may develop, and those areas could get a quick burst of snow that might even cover road surfaces.  I don’t think that there will be major problems in the morning, but enough in some areas for delayed openings.  Harford county has already delayed by two hours, and I’d expect others will too, especially along the northern tier of MD.

Looking ahead, there are already some indications of another system early next week, and looking really far ahead, Christmas looked like a Thomas Kinkade painting (man, I hope Tom Clifton still reads this blog.  He hates TK).  Though, be forewarned, the models haven’t been very accurate in the long term recently, so don’t get your hopes up.

Tuesday, December 10th, 2:30PM

The midday model runs have finished and most agree that late tonight, the rain we have will slowly transition to snow showers and bring a slushy coating to as much as 2″ on mostly grassy surfaces.  In some areas, there may be some heavier bands of snow that may cover roadways, but for the majority of the area, road surfaces will probably not accumulate.  However, temperatures are expected to fall into the low 30’s across the area so icy conditions are possible for the morning commute.  Based on the most recent model runs, the NWS has issued Winter Weather Advisories for areas along and west of the Blue Ridge for overnight and tomorrow morning for up to 5″ of snow across the summits, and also advisories for the morning commute until 8AM for the western portions of the 95 corridor including northern Baltimore, western Howard, and western Montgomery counties. Here is the link to the NWS map.

For now, those advisories do not include the immediate 95 corridor, but if by 11PM this evening, the models are still showing the possibility of snowfall or near freezing temperatures for the morning commute along the corridor, I’d expect advisories would be expanded east to include the eastern portions of Baltimore, Howard, Montgomery and the rest of the counties to the bay.

I’ll update again tonight before going turning in.

Tuesday, December 10th, 7:30 AM

For those that don’t know, HoCo has implemented a new color code system for emergency closing.  Apparently, the old system of telling employees the opening status in words was problematic because “staff (were often) confused regarding their work status when there were emergency and other non-scheduled school closings.”  I’m not sure what staff had trouble with the old system, but hopefully the new system makes it easier for all of us.  And in the spirit of alliance, here at the Weather Mill, we’ve implemented a new color to indicate that we have no idea what’s going to happen.  So, here we are, 24 hours from our first possible event of the year, and we are still looking at a very muddy forecast which makes us officially Code Chocolate Brown.

What is certain is that a cold front will cross the area later today and temperatures will slowly fall later this evening and overnight.  The problem with a system like this is that we are trying to time a lagging piece of energy along the cold front that will bring precipitation back into the area later this afternoon, and the arrival of cold enough air to change the rain to snow.  In most cases, these situations do not work out for us as the precipitation usually shuts off with the arrival of the colder (and drier) air.  However, the models have been insistent that there will be enough moisture left before sunrise tomorrow, and enough cold air, to give central MD a dusting to 2″ of snow (at least that’s what the models are suggesting).   I’m reluctant to believe that, but the other aspect to consider is that regardless of how much snow falls, there will likely be wet surfaces tomorrow just before sunrise, and temperatures that will be right around freezing, so we may have some problems with the morning commute whether it snows or not, especially west of I 95.  It’s still early, but in reading their discussion this morning, the NWS expects Winter Weather Advisories to be issued for counties west of I 270 for later tonight and tomorrow morning, and also thinks that there’s a chance they’ll have to push the advisories east to include central MD.   But for now, Code Chocolate Brown.

Once I see the midday model runs, I’ll post a more specific update early this afternoon.

Sunday, December 8th, 9:30 AM

After a seasonably cold weekend, we look to a warm up and rain for the early part of the work-week, but another cold front will cross the area Tuesday evening that may bring some wintry precipitation to areas west of the bay before sunrise Wednesday morning. It’s not an ideal setup because timing the arrival of cold air and departing precipitation doesn’t work out often for this area, but all the models suggest that the 95 corridor could see some light accumulations, and even a moderate event just north and west of the cities, by early Wednesday. It’s still three days out, so obviously there will be changes.

I’ll post the snow contest entries later today and update on the model runs as necessary.

Tuesday, December 3rd, 10PM

We may see our first flakes of the season overnight as some snow showers will cross the area and may bring a coating of accumulation to areas mainly west of 95, and mainly on grassy surfaces.  In most areas there should not be enough to cause travel problems in the morning except maybe along the MD/PA line in Carroll and Frederick counties where temperatures may be cold enough for some icy conditions through sunrise.

Also, we’ve had a great turnout for the Snow Contest and I’ll be posting the spreadsheet later this week.

3PM October 31

Severe weather is not something I normally report on, but with many activities planned for this evening, I thought it might be a good idea to be sure everyone has some idea what the weather will be for the trick or treaters.

A strong cold front is approaching the area this afternoon, and out ahead of it into the evening will bring cloudy skies, gusty southerly winds, and occasional showers, but nothing severe.

There’s good model consensus that the cold front will enter the western areas along the Blue Ridge around 8PM and make it to the bay before 11PM. When the front crosses, severe storms are likely with very gusty winds, dangerous lightning, and heavy rain. Isolated tornadoes are a strong possibility, but even without tornadoes, the straight-line winds are expected to be strong enough for some damage.

In short, it’s safe to put on your best costume and go trick or treating, but the earlier the better. By 9 or 10 o’clock, the front will bring very fast-changing conditions with severe weather likely. Behind the front will be gusty and much colder.

Be safe!

Precipitation will develop across central MD early this afternoon and will be a mixed bag for most of us along the 95 corridor.  In the areas that are all snow, daytime travel should be fine because of marginal temperatures and a March sun, but once the sun sets, roads will probably deteriorate quickly in the areas that are all snow.  The models differ on where the rain/snow line will set up, but it will probably be right along the fall line west of 95.  On the snow side of the line, travel tonight will be tricky when the heaviest snow is expected.

All precipitation should eventually change to snow later tonight and end early Monday.  Totals will be mostly on grassy surfaces until much later, and I expect a sloppy inch or two along 95 by morning and 6″ or more as you go west and north.

A significant winter storm is in the works for areas west of 95 tomorrow and tomorrow night with snow beginning tomorrow around noon and continuing into tomorrow night. Many areas will see mixed precipitation throughout the day tomorrow, and although I don’t have a lot of time to delve into specifics now, expect accumulations of 2 inches from just east of 95 to 6 or more inches in western areas.

I won’t be able to give a more specific update until very early Sunday morning, but just know that travel will be difficult in western and northern areas of the area beginning early tomorrow afternoon.

The very active pattern continues, and the second wave that I mentioned yesterday is developing very well this morning (Friday, 9AM) to our south and will likely bring a swath of moderate to heavy precipitation across the area beginning at about 6PM this evening and lasting into early Saturday morning.  For most of us along the 95 corridor, this will be a cold rain event, but for areas west of I 270 and north along the MD/PA line, this could be a short-lived heavy snow event.  Be careful if traveling in those areas overnight.  Where the rain/snow line sets up is still uncertain at this point, and if there are changes in the midday model runs, I’ll update this afternoon.

Regardless of what happens locally for tonight’s storm, it’s development has ramifications for us Sunday afternoon into Monday.  If you want snow, you want tonight’s storm to deepen rapidly and force cold air over us in its wake.  Right now the Sunday afternoon and evening system is too close to call, but it has been trending slightly colder with each model run, so there is still potential for an accumulating snow event, especially to the west and north of I 95 Sunday evening into Monday.  I’ll update on its potential over the weekend.