9:40 p.m. update: Snow and rain exits west to east now through around 11 p.m. Many places north and west of the District have received a light coating mainly on grass and elevated surfaces, with a small road accumulation in northern Montgomery County, Loudoun County and to the north and west. A few slick spots are possible in the morning but school delays are unlikely.
7:50 p.m. update: The snow line has advanced south and east and is almost to the District. It may keep advancing some more before precipitation ends around 9-11 p.m. A coating is possible mainly from the District toward points north and west on grass, cars, roofs and other elevated surfaces (such as that already seen in Damascus).
6:30 p.m. update: Reports indicate a rain/snow mix has mainly changed to snow from Frederick to Leesburg and to the north and west, and even spots in northern Montgomery and western Howard county are getting snow.
A mix of rain/snow/sleet continues south and east of those locations until you get inside the beltway and to the south and east, where mostly rain is falling. For places currently mixing, you may well go over to mostly wet snow in the next hour. The snow line should continue push ing east so don’t be surprised to see some mixing work inside the beltway with precipitation possibly ending as a period of wet snow.
Accumulations - mainly in Loudoun, Frederick, western Howard, and northern Montgomery counties - will tend to be mainly on grassy areas. Precipitation should begin to exit 8-10 p.m. from west to east.
5:35 p.m. update: As temperatures have cooled into the upper 30s to low 40s, we’re getting reports of rain mixing with sleet and snow, especially in our north and west suburbs outside the beltway. In order to find all snow, you need to get to I-81(Winchester was reporting snow and 34 at 5 p.m.) but the snow line should advance east into Frederick and Loudoun counties in the next hour or so.
Plentiful clouds throughout the day foretold our next weak little storm system. Some places around the area are already seeing showers, even mixed with a few pings of sleet at the onset. After highs reached the mid-to-upper 40s most spots, it’s not going to be too easy to get any real wintry weather with this one.
Through Tonight: Showers may eventually transition into more of a general light rain mid-evening as the storm system strengthens a bit. Rain could mix with sleet or snow at times, particularly north and west of the city. A brief period of all snow is even possible, again favoring elevated areas north and west. However, even in spots that see any sleet or snow, temperatures should not get to or below freezing until things end. Add in generally light rates, and even getting a dusting could be tricky. Many spots might end up only seeing rain. Rain or light snow should mostly be pulling away by about 8 p.m. (west) to midnight (east). Lows eventually reach near 30 to the mid-30s.
Tomorrow (Thursday): You may want to at least be aware of the potential for an isolated slick spot in the coldest areas pre-sunrise, as wet patches may freeze for a time. That minor issue disappears fast though. Skies should be on their way to mostly clear by morning if not already there. Then we see the same throughout the day, with light winds from the northwest shifting to the south. Highs rise to around 50.
Pollen: Notice any extra sneezing? Tree pollen is (before the rain) already at moderate levels locally. This is on the heels of an above average January when it comes to tree pollen, much like last year. Both years were well above average in January when it comes to pollen. All other pollens and molds are low.