|Dew Point:||34.3°F (1.3°C)|
|Sea Level Pressure:||30.36" (1028.0 mb)|
Light Rain LikelyHigh: 45 Low: 37
Chance Light Rain then Chance Rain ShowersHigh: 47 Low: 28
Partly SunnyHigh: 41 Low: 28
SleetHigh: 32 Low: 32
Rain And Snow Likely then Chance Rain And Snow ShowersHigh: 45 Low: 31
Rain likely. Cloudy, with a high near 45. South wind 2 to 6 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch possible.
Rain and patchy fog. Cloudy, with a low around 37. Northwest wind around 3 mph. Chance of precipitation is 100%. New rainfall amounts between a half and three quarters of an inch possible.
A chance of rain and patchy fog before 7am, then a chance of rain showers and patchy fog between 7am and 4pm. Cloudy, with a high near 47. Northwest wind 3 to 9 mph. Chance of precipitation is 40%. New rainfall amounts between a tenth and quarter of an inch possible.
Mostly cloudy, with a low around 28. Northwest wind 5 to 9 mph.
Partly sunny, with a high near 41. North wind 2 to 7 mph.
A chance of snow and a chance of sleet and a chance of freezing rain after 1am. Mostly cloudy, with a low around 28. Chance of precipitation is 30%.
Sleet and freezing rain and snow likely. Cloudy, with a high near 32. Chance of precipitation is 90%. New snow accumulation of less than one inch possible. New ice accumulation of less than half an inch possible.
Freezing rain before 10pm, then rain between 10pm and 1am, then rain and snow likely. Cloudy, with a low around 32. Chance of precipitation is 100%. New ice accumulation of less than half an inch possible.
Rain and snow likely before 7am, then a chance of rain and snow showers between 7am and 1pm. Partly sunny, with a high near 45. Chance of precipitation is 60%.
... Low pressure will move toward the Mid-Atlantic tonight into early Tuesday. A cold front will pass through the area late Tuesday with high pressure returning on Wednesday. Low pressure will likely impact the area Thursday and Thursday night before shifting to the northeast on Friday. High pressure likely to return next weekend.
NEAR TERM /THROUGH TUESDAY/... Clouds continue to thicken this afternoon ahead of a low pressure system along the Gulf Coast. Temperatures are holding in the 40s, topping 50 in a few spots near and east of I-95. Dew points are still in the 20s west of the Blue Ridge and mid 30s to the east, so the approaching shield of rain will initially be light as it saturates the column. Suppose there could be a few sleet pellets at precip onset, mainly west of the Blue Ridge. One other remote possibility over the Highlands this evening is a brief period of freezing rain as wetbulb processes cause temperatures to drop. However, even if air temperatures did briefly dip to 32, would not think there would be any impact since surfaces are warm and there are no processes (e.g., surface cold advection) to maintain temperatures AOB 32. Hot Springs VA demonstrated this trend, dropping to 33 at precip onset then rising to 37.
A secondary area of low pressure will form along the coastal front in the Carolinas tonight before lifting north of the area Tuesday morning. A low level jet will provide additional forcing for widespread moderate to locally heavy rainfall. The steadier rain will begin to taper off late tonight into Tuesday morning. Areal average rain totals should range between 0.50 and 1.50 inches, highest in the southeast. Flooding should not be a significant issue, but can't totally rule out some urban and poor drainage problems. Low temperatures will range from the mid 30s to mid 40s.
A cold front trailing Canadian low pressure will pass through during the day Tuesday and scour out lower clouds and any lingering drizzle. However, the frontal zone/trough axis aloft will be slow to push to the southeast, and the area will be located under the right rear quadrant of the upper jet. So the chance for showers will remain, and a band of steadier rain may develop from Charlottesville to southern Maryland. Upslope precipitation west of the Allegheny Front will also continue and eventually change to snow as cold advection commences. However, a lot of the saturated layer is warmer than -10C and the QPF will be light, so less than an inch of accumulation is expected. In the lower elevations, highs will range from the mid 40s to mid 50s.
SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... High pressure will build in from the west Tuesday night and pass off to the north on Wednesday. The weather will be dry, but the jet stream will likely lead to some high clouds. Lows will fall below freezing in many spots Tuesday night, followed by highs in the 40s on Wednesday.
Upper level trough over the Mississippi Valley will lead to cyclogenesis to our southwest, with moisture spreading toward our area Wednesday night. High pressure will remain in place to our north, forming a cold air damming pattern. The high is also cold and dry -- dew points are expected to be in the teens and 20s to start the night. Temperatures will likely fall below freezing for much of the area, especially west of I-95. The biggest question about this system at the moment is the timing. An earlier start time to the precipitation would likely mean more potential for wintry weather (and ensuing impacts). Have used a blend of guidance for PoPs for now, which keeps things in the chance category until 12Z. Regardless of timing, guidance indicates a warm layer aloft, so all precipitation types could be in play since temperatures will be cold to start the day. Additional thoughts continue in the next section.
LONG TERM /THURSDAY THROUGH MONDAY/... A developing low pressure system will move up the East Coast Thursday into Thursday night. Rain, moderate to heavy at times, will overspread the region from south to north. At the onset, some areas in the northern half and interior Shenandoah Valley and Virginia Piedmont of our CWA could experience a wintry mix of sleet and snow or sleet and freezing rain. This could especially be true if the precipitation comes in early, particularly early to mid-morning, rather than mid-afternoon. Models, such as the EURO and the GFS bring the leading edge of the precipitation into northern Virginia and eastern West Virginia an hour or two after sunrise Thursday. This scenario would allow for a mix of sleet and some freezing rain. There should be a layer of warmer air a few thousand feet thick above the boundary layer poke in from the southwest. Therefore, the snow factor for a large part of northern Virginia and eastern West Virginia should be low in confidence, if not any. The NAM model brings the leading edge of the precipitation into the same zones around mid-afternoon. This scenario would result in many rain across most of our CWA Thursday, except for higher elevations like the Blue Ridge and ridges of western Maryland and eastern West Virginia. We have a few more model runs to decide on where and when any wintry precipitation will occur this Thursday into Thursday evening. In the meantime, it is best to be prepared for a little wintry mix in most area, especially along and south and west of U.S. 15 from the Mason- Dixon line to Orange County in Virginia.
As most areas transition from a soaking rain or wintry mix over to areas of drizzle or intermittent rain or snow showers Thursday night, the main coastal low pressure system will depart off of the East Coast by Friday. Colder and drier air will be usher in on a building area of high pressure during the period of late Friday through Saturday.
A storm system over western Quebec Canada will move east into the maritimes and bring an Arctic front southeastward across the Eastern Great Lakes into the mid-Atlantic Saturday night and Sunday. A reinforcing area of high pressure will push the Arctic front southward and usher in cold air into our region on Sunday. The reinforcing surge will just guarantee our below average temperatures Saturday night and Sunday.
Below to well below average temperatures throughout the extended forecast. Highs Thursday will range from the lower 30s in the west to near 40 in metro D.C. to near 50 in southern Maryland. These temperatures are a result of cold air in place, cloud cover and wintry mix or rain arriving during the day. Highs Friday and Saturday will range from the upper 30s in the west to near 50 in metro D.C. to the middle 50s in southern Maryland. Chilly high pressure will be the cause of these temperatures. Reinforcing high pressure will only allow high temperatures to reach the middle 30s in the west, the middle 40s in metro D.C. and the lower 50s in southern Maryland for Sunday.