|Dew Point:||27.0°F (-2.8°C)|
|Sea Level Pressure:||26.86" (909.5 mb)|
Light RainHigh: 43 Low: 31
Mostly SunnyHigh: 41 Low: 23
SunnyHigh: 42 Low: 29
SunnyHigh: 53 Low: 40
Rain and patchy fog. Mostly cloudy, with a low around 35. Southeast wind around 7 mph. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.
Rain and patchy fog before 5pm, then a chance of rain showers. Cloudy, with a high near 43. Northwest wind around 9 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
A chance of rain showers before 8pm. Mostly cloudy, with a low around 31. Northwest wind 9 to 23 mph, with gusts as high as 26 mph. Chance of precipitation is 50%. New rainfall amounts less than a tenth of an inch possible.
Mostly sunny, with a high near 41. West wind 23 to 26 mph, with gusts as high as 43 mph.
Mostly clear, with a low around 23. Northwest wind 21 to 25 mph, with gusts as high as 40 mph.
Sunny, with a high near 42.
Clear, with a low around 29.
Sunny, with a high near 53.
Mostly cloudy, with a low around 40.
... Coastal low pressure will develop over North Carolina tonight and the low will pass through our area Thursday. The low will intensify as it moves off to the northeast Thursday night through Friday and high pressure will return for the weekend. Low pressure may impact the area early next week with more unsettled conditions possible.
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Clouds continue to gradually lower and thicken tonight ahead of low pressure developing over the eastern Carolinas. Intermittent light rain already encroaching on southern Maryland as of early this evening, and rain is expected to expand quickly northward while increasing in intensity after midnight (mainly east of Interstate 81). Some moderately heavy rain is likely by daybreak between the Blue Ridge and Interstate 95.
SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... There is a decent chance this system will be an "overperformer" when it comes to precipitation amounts. Strong height falls with an approaching negatively-tilled mid/upper trough, attendant mid and upper jet/PVA, and strong low-level moisture flux all point to an area of moderately heavy rain from Thursday morning the mid Thursday afternoon across northern Virginia and central Maryland (mainly between the Blue Ridge and I-95). In addition, mid-level lapse rates of around 7 C/km will contribute to embedded convective elements/heavier rainfall rates (possibly 1/2 inch per hour). A few rumbles of thunder are possible as well given all the strong forcing in place, despite low CAPE values (less than 200 J/kg).
The low pressure system will be intensifying NE of our area Thursday night and the shortwave will phase with additional northern stream energy on Friday. This will cause some showers to develop on Friday afternoon. In the meantime, high pressure will be building west of our region over the central CONUS. The gradient from this and the low pressure suggests that gusty NW winds will develop over our area Friday into Friday night. Gusts between 30 and 40 mph are possible across most of our CWA, and gusts up to 50 mph are possible over higher elevations/west of the Blue Ridge. Snow showers west of the Allegheny Front are possible during this time as well, with dry conditions expected elsewhere.
LONG TERM /SATURDAY THROUGH WEDNESDAY/... High pressure will gradually build over the region through the day Saturday as shortwave ridging aloft moves into the Ohio Valley. Enough of a pressure gradient will exist between the building area of high pressure and the departing low over the northeast to maintain some gusty winds through the day. However, winds are gradually expected to diminish late Saturday as the low moves further away and the gradient relaxes. The high will move overhead Saturday Night, then slide offshore on Sunday. This will allow a southerly return flow to develop, enabling warmer conditions to work their way back in. High temperatures will run about ten degrees warmer on Sunday with highs in the low 60s (compared to the low 50s on Saturday).
On Monday, disturbances in both the northern and southern streams will start to approach the area. Model guidance differs substantially with respect to the handling of these disturbances, casting rather high uncertainty on our sensible weather forecast for the Monday through Tuesday time frame. In terms of deterministic solutions, the 12z GFS has a strong northern stream disturbance and a more diffuse, weak southern stream disturbance. At the surface, this solution results in a strong area of high pressure developing over the Upper Midwest, and a strong, progressive cold front being driven southward across the area late Monday through Monday Night. This would result in a period of precipitation late Monday afternoon through Monday Night that would clear the area by Tuesday morning. The 00z Euro, on the other hand, showed a slightly weaker, further northward displaced northern stream disturbance, and a stronger southern stream disturbance (compared to the GFS solution). This combination results in the baroclinic zone stalling out overhead and a more prolonged period of precipitation Monday through Tuesday. The general notion of a low predictability forecast is supported by the 00z EPS members, which show more than 30 degrees of spread in the temperature field through much of the Monday Night through Wednesday time period.
To summarize, the general synoptic pattern appears favorable for us to see some precipitation at some point during the late Monday through Tuesday timeframe. However, most of the finer scale details, including the timing, duration, and character of the precipitation remain in question. There's plenty of cold air associated with the northern stream disturbance, so some wintry precipitation isn't entirely out of the equation, even at lower elevations. However, given the level of uncertainty it's far too early to speculate with respect to what will happen with precipitation type.