Tuesday Threat Update and Prediction

 UPDATE: WINTER WEATHER ADVISORY FOR ALL OF MOCO. 1-3" OF SNOW EXPECTED. IT ALSO SAYS VISIBILITY COULD BE LESS THAN 1/2 OF A MILE AT TIMES, AND COULD EXCEED 1 INCH OF SNOW PER HOUR!

This snow threat has just boomed since yesterday, and all the models(except HRRR) show at least 0.4 inches of snow. The Euro shows 1.2-1.6"(1.6-2" in some areas)(anything in parentheses is the majority amount for the county), the ICON shows 0.4-0.8 inches(0.8-1.2" in some areas, 0.2-0.4" in some areas), and the GFS shows 0.8-1.2"(1.2-1.6" for NE areas, 1.6-2" for Damascus, and 0.4-0.8 inches for Bethesda). This storm will start at 11AM-12PM, starting as rain for some, mixed rain/snow for most, and pure snow for NE areas. By 1-2PM, it should be all snow for the whole county, and by 7PM the system should be out. Most of the snow should stick on the grass(more snow sticks on sidewalks/roads the more north you go), but visibility is a problem and so is slush. Temps should be hovering above freezing, so snow will have a harder time sticking to the ground. However, it will be a huge mess. Mixed rain and snow will cause slush, and since temps are 33-35 degrees, slush can come as an outcome of this storm, mainly in our north areas. Slush is slippery, and it will be a mess outside. Even if temps are above freezing, it could still stick to sidewalks and neighborhood roads. Since temps are 33-35, if the snow falls at a moderate to heavy rate, it could stick to areas students will walk on, and then those areas will become slippery and students will be vulnerable to falling and getting serious injuries. By 3PM, there could already be an inch of snow on the ground, and at1PM there will only be a coating. If enough snow falls at a heavy enough rate, it will stick to sidewalks and roads and/or make those surfaces very slick. Anyways, let's look at the maps now! First, we have our map from the NWS. PREDICTION:  2 snowflakes(delay chance is early release chance)(65% chance of early release)(30% chance of no school)(modified)(see rating system)(not 2.5 snowflakes because closure chance not as high)(look down for details)

The NWS predicts 1-2" FOR THE WHOLE COUNTY and 2-3" for the upper quarter of MoCo. This means that the NWS thinks 1-3 inches throughout the whole county. 1 inch of snow should be enough to cause issues throughout the whole county, and it gets far worse the more north you go. Some places could get 3 inches! This is enough snow to cause an early dismissal. This will definitely cause issues with the afternoon commute. If this forecast is correct, after school activities will be cancelled, and this will probably cause an early release. 3-4PM is supposed to be when the snow is at its heaviest. That is when lots of students get dismissed(elementary school students), and some high school students(Poolesville High School students) leave school at 4:30PM, and it is probably already  snowed enough to make everything slick, slushy, and icy. January is the coldest month of the year, so sun angle isn't a factor and temps should find a way to make surfaces at least a little bit slushy. Now, lets at Capital Weather Gang's map!

As you can see, most of MoCo is in the 1-3" area.The C-2" area says that most of the accumulation is on the grass, but the 1-3" area says SLICK ROADS POSSIBLE. This means that if slick roads are possible, slick/slushy sidewalks are likely. All of MoCo (according to this map) won't be getting a mix. Just because the C-2" area doesn't have as much snow potential as the 1-3" area doesn't mean that they will get less snow than the dark blue(dark blue will get more snow than the light blue area)(most likely). It just means that they don't have as much potential than the dark blue area to get more than 2 inches; they just probably won't get over 2"(a place in C-2" could get 2" and a place in 1-3" could get 1"). A place from the light blue area can get more than the dark blue area; it is just less likely. This is a map that I agree with; however, I think the C-2" area(not including MoCo) will have mixing in some spots. This map(if most correct) would cancel after school activities, and we would have an early release(if this map was the most correct I would go 57/43 with the early release).(this map was updated due to the new advisories). (1-3" area could get 3-5" if the totals are more than what is forecasted, C-2" area would get 2-4" if more snow falls than what is expected, 1-3" area could get 1"> if less snow falls than what is expected, C-2" area could get a bare ground if less snow falls than expected)(bare ground means that snow will fall but it won't stick to anything, not even grass). Now, let us look at WUSA 9's map!

(UPDATE: ALL OF MOCO IS IN 1-3" OF SNOW AREA NOW! IT ALSO DOESN'T SAY SNOW WILL MAINLY BE ON GRASSY AND ELEVATED SURFACES! 65% chance of early release!) This map has about 51% of MoCo in the D-1" area, while the other 49% is in the 1-2" area. However, since MoCo is so close to the 1-2" area, for MoCo (specifically), this map will show 0.65-2" for the whole county. The map says that the gray area's accumulations will be mainly on grassy and elevated surfaces(i think for only the gray area?!), so the impact wouldn't be that bad in those areas(maybe some delays)(same with the white area but much more delays and some cancellations). Despite how much snow these maps show, after school activities will be cancelled. This could still cause some slick spots, 0.85"+ is enough to make roads slippery, at least a little bit. This could still definitely cause an early release, I am just not as confident as I would be compared to the other two maps we already saw. Anyways, let's look at the NBC 4 map now

As you can see, 5/6 of MoCo is in the 2-4" area, while the other 1/6 is in 1-2" area. This is enough snow to cause delays and even cancellations(3"+ of snow usually will cancel school if it snows the whole day)! This is far more than enough snow to cause roads/sidewalks to be slick and/or slushy and even snow covered! If this was correct I would go (75% of early release, 25% full day). Now, let's look at the details for my prediction!

Mixed rain/snow turning into snow around 12 PM and ending at 7PM will really put a wrench into the afternoon/evening commute. The snow amounts are 1"+ for lots of places in the county, and the snow is expected to fall at a moderate rate. By 1 PM, there could be a coating on the ground, and by 3 PM, there could be an inch! The snow will fall fast, and even if temps are 32<, the snow will be able to fall fast enough to stick to bus stops and sidewalks, and even secondary/neighborhood roads in upcounty will be affected! There is a huge difference of snow on the ground between 1 PM and 3PM, and by 3 PM, there should be enough snow that has fallen on the ground to make surfaces(sidewalks, bus stops, etc.) slushy and/or slick, especially in upcounty! If they release early, students will get to home easily with no injuries due to weather! Visibility will be low, and it will take longer for students to get home if released on the normal time. The reason I think there won't be a delay or closure is because snow will fall after the delay time and it would have no effect, and no closure because it won't be snowing the whole day, only the afternoon, so closing wouldn't happen, because MCPS would try to get as much hours of school they can while still taking the student's safety into consideration.I am leaning towards a delay because there will be a significant difference of snow on the ground if released early compared to normal dismissal. Upcounty will be a huge mess, and the amount of snow we are talking about is enough to cause some issues on the roads(more of a slush/slick problem, not snow accumulation problem). It will be dangerous for students to walk on slushy sidewalks, and even slick spots because these increase the chances drastically of a student breaking a bone and falling. There are some places that won't see a plow for a long time, so the snow will be an issue for who knows long before it gets removed. Also, since winter weather advisories have just been released for the whole county this increases the chance of an early release(since all of MoCo is in the advisory). The advisory tells people that this is something that could disrupt their  plans and will make people aware  that there is a winter weather threat that could be potentially harmful for your health. It also says at times visibility could be less than 1/2 of a mile at times, and that snowfall rates could EXCEED 1 inch per snow per hour. These are near blizzard conditions(visibility). Walkers will suffer a lot, because they can't see that well and 1 inch per hour+? Walkers will suffer even more(more snow to walk through and snow will stick to almost everything so more slick and slushy spots) and snow will stick to almost everything, since the rate is so heavy that it will reduce surface temps to 32(maybe even lower), that there will be slush and black ice everywhere. This is all if MCPS doesn't release early. If they do, all of this will be avoided. If they don't, well... R.I.P. Walkers. This could cause a delay the next day(Wednesday), so stay tuned for that(temps 32> Wednesday Morning and Tuesday Night).