|Dew Point:||1.4°F (-17.0°C)|
|Sea Level Pressure:||28.67" (970.9 mb)|
Partly SunnyHigh: 39 Low: 30
Partly SunnyHigh: 42 Low: 31
Light RainHigh: 44 Low: 39
Rain then Rain Showers LikelyHigh: 49 Low: 35
Chance Rain ShowersHigh: 44 Low: 33
Partly sunny, with a high near 39. South wind around 7 mph.
Mostly cloudy, with a low around 30. Southwest wind around 7 mph.
Partly sunny, with a high near 42. South wind around 6 mph.
Mostly cloudy, with a low around 31. Southeast wind around 6 mph.
Rain and a chance of freezing rain after 7am. Cloudy, with a high near 44. Southeast wind 5 to 8 mph. Chance of precipitation is 80%.
Rain. Cloudy, with a low around 39. Chance of precipitation is 90%.
Rain before 7am, then rain showers likely. Mostly cloudy, with a high near 49. Chance of precipitation is 90%.
Rain showers likely. Mostly cloudy, with a low around 35. Chance of precipitation is 60%.
A chance of rain showers. Partly sunny, with a high near 44. Chance of precipitation is 40%.
... High pressure will linger over the region through Thursday night. A large area of low pressure will impact the area at the end of the week bringing widespread rain and potential for flooding.
NEAR TERM /THROUGH TONIGHT/... Scattered to broken clouds are being observed along the northern tier of the CWA this morning as a shortwave trough slides eastward through southern Pennsylvania. At the surface, a weak frontal boundary is making its way southward from the Mason Dixon Line, helping stir winds up a bit. This in combination with the added cloud cover, there has been quite the spread in temperatures over the area early this morning. To the north where more clouds are prevalent, temperatures have been holding in the mid to upper 30s, while locations in the Shenandoah Valley and northern Virginia where we have decoupled, temperatures are solidly in the teens. Much like last night, areas that saw snow melt yesterday, be cautions of patchy ice spots when heading out this morning.
The aforementioned shortwave trough axis will move off the Mid Atlantic coastline this morning as mid to upper level ridging builds overhead, keeping conditions dry today. Mid to high level clouds will be more evident today as the next surface and upper low nears the Great Lakes and additional shortwave energy tracks overhead. The weak surface boundary will likely stall out over the region, but with a lack of moisture and near non- existent forcing, this boundary will be of little consequence to our weather. High temperatures today will be similar to yesterday, topping out in the upper 30s to middle 40s.
Clouds continue to increase tonight as warm air advection improves aloft and the upper low tracks across northern PA and southern NY. The best forcing and likelihood of precipitation will reside to our north across PA, but the increase warm air advection may result in light wintry precipitation over western Maryland and the Allegheny Front. Moisture again will be very limited, with just a few hundredths expected over the upslope areas, but light freezing drizzle/snow will be possible. Cloud cover will maintain temperatures overnight in the upper 20s to lower 30s for much of the area.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... The upper low will slide eastward into southern New England on Thursday with mid to upper ridging again building overhead, with dry conditions forecast after any light precipitation comes to an end early Thursday morning. Temperatures a touch warm on Thursday in the low to middle 40s, with a mix of sun and clouds expected.
Skies will trend mostly cloudy by Thursday evening as the next system approaches the Tennessee Valley. Models continue to trend with precipitation holding off until later Friday morning and into the afternoon. Any precipitation that is able to make it into the Highlands and southern Shenandoah Valley early Friday morning could be in the form of freezing rain with cold air stubbornly locked in at the surface. If trends continue later, this threat may not even materialize as temperatures will favor above freezing. As temperatures do rise above freezing Friday morning, rain will fills in over the area from southwest to northeast during the afternoon and early evening hours. Moderate to heavy rain is expected to fall Friday night as low pressure nears the Carolinas. Rainfall amounts on the order of a half inch to one inch will be possible by daybreak Saturday. This combined with the snow melt may result in incidents of flooding. Additionally, with this rainfall, the yearly rainfall record for Washington DC will likely fall Friday night, as only 0.55 inches is needed to tie the current record (see climate section below). Highs on Friday will range in the 40s to lower 50s, with lows Friday night seasonably warm in the upper 30s to middle 40s.
LONG TERM /SATURDAY THROUGH TUESDAY/... A large and complex area of low pressure will linger over the region through the weekend before exiting by early next week. However, we do not expect a washout, and with temperatures rising slightly above normal, it could feel a bit more comfortable in some regards. Early Saturday, the heaviest rain with the initial wave of low pressure should be exiting the region, though some may linger in the morning. After that, however, we will remain cloudy with a risk of showers as the upper level system will still need to clear the region. There are indications a secondary low pressure system will develop as the upper low approaches, which could cause showers to persist through the day Sunday. Temperatures will remain mild, with 40s and even some 50s common, so do not expect significant wintry weather, though the highest elevations could see a little wet snow.
GFS and ECMWF both show a cold front crossing southeastward through the region on Monday as the weekend system finally moves out. It is fairly moisture starved, so the main precip threat would be some upslope rain/snow showers. Of note is a significant air mass difference between the guidance, with the ECMWF showing little cold air behind the front, while the GFS shows a brief shot of below normal temperatures. However, even the GFS is brief with it, and temps likely return to normal or even slightly above normal later next week as high pressure of Pacific origin builds across the region.