|Dew Point:||51.0°F (10.6°C)|
|Wind:||From the SE at 4.7 MPH Gusting to 11.0 MPH|
|Sea Level Pressure:||26.41" (894.2 mb)|
Mostly CloudyLow: 54
Rain Showers LikelyHigh: 65 Low: 51
Rain Showers LikelyHigh: 59 Low: 40
SunnyHigh: 50 Low: 41
SunnyHigh: 53 Low: 43
Mostly cloudy, with a low around 54. South wind around 12 mph.
Rain showers likely after 8am. Mostly cloudy, with a high near 65. South southeast wind 12 to 22 mph, with gusts as high as 25 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch possible.
Rain showers before 11pm, then showers and thunderstorms. Mostly cloudy, with a low around 51. South wind 16 to 26 mph, with gusts as high as 30 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.
Rain showers likely. Mostly sunny, with a high near 59. West southwest wind 12 to 15 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch possible.
A slight chance of rain showers before 8pm. Partly cloudy, with a low around 40. West wind 10 to 14 mph. Chance of precipitation is 20%.
Sunny, with a high near 50.
Partly cloudy, with a low around 41.
Sunny, with a high near 53.
Mostly clear, with a low around 43.
High pressure has moved off the coast of Nova Scotia. A frontal boundary is situated over the Mississippi Valley with an area of low pressure over southern Manitoba. The front will push into the Mid Atlantic tonight before becoming wrapped into the northern low once it moves over the Upper Great Lakes. Upper troughing will remain north of the region during the second half of the week.
NEAR TERM /TODAY/...
After an extended period of tranquil weather the weather pattern will become much more complex for the next 24-36 hours. As written in the synopsis high pressure has pushed east of Atlantic Canada while weak pressure/frontal boundary stretches the length of/just east of the Mississippi River. Another area of low pressure is centered near Winnipeg. This is associated with a developing upper level trough.
As the high moves away both low pressure areas will push east. Over the next 18-24 hours these two will merge into an upper level low over the upper Great Lakes. For the day expect to see increasing clouds but a continuation of the above average temperatures. Highs in the mid 70s except cooler in the west where cloud cover will be greater.
Precipitation chances will increase/spread east as the day progresses.
Speaking of temperatures - according to our daily climate summaries IAD has been 6.2 degrees above normal so far this month. DCA is 6.4 degrees above. BWI 6.5 above.
DCA is 1.58" below for the month on precipitation. BWI 0.96" below. IAD 0.81".
SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
Tonight looks like the most active period time of weather. Front will be crossing the forecast area between 00Z and 12Z, with the band moving east of the mountains after 03Z. Ahead of the front winds are expected to be 30-40 knots at 2000 feet. The winds will be turning in that layer as well. The missing ingredient will be CAPE. But area is outlooked overall as being in a marginal risk east of the mountains - a sliver of Nelson County is included in slight risk. Still, gusty showers with isolated thunder can be expected, and given that low level wind field we'll have to keep eyes on the radar this evening into the overnight hours.
QPF of around 1" can be expected. Lows in the 60s east of the mountains, 50s west.
Tuesday the front moves off the coast - but models really don't take it very far offshore. As a result we have chance PoPs over much of the region. QPF will be low. Wind field will still be out of the southwest, so temperatures will still be quite warm for late October. Much of the region will top out in the lower 70s.
Afterwards the upper trough will draw closer to the northeast US. Temperatures Tuesday night will still be above normal, but somewhat closer to normal as lows drop back into the upper 40s east of the mountains. Likewise Wednesday's highs will be in the lower to mid 60s, much more like what a "normal" late October would be.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Ridging will build back into the region later Wednesday night into Thursday and remain in place through at least Friday. At the same time, a low pressure system will track from the upper Midwest, through the Great Lakes region, and then northeastward into Canada towards Hudson Bay. The associated cold front will gradually push eastward, moving into the Mid-Atlantic states during the Saturday/Sunday time period. Potent upper level energy diving southeastward behind the front may also act to help develop an area of low pressure along the front before pushing eastward offshore.
In terms of sensible weather, fair weather is expected for Thursday/Friday with chilly but seasonable morning lows (30s/40s) and near or above normal highs (60s-70). Chances for rain will then increase over the weekend, especially on Sunday as the frontal system passes through. Temperatures may be above normal on Saturday at least prior to frontal passage, but will fall below after frontal passage.