|Dew Point:||70.9°F (21.6°C)|
|Sea Level Pressure:||30.26" (1024.6 mb)|
Slight Chance Rain ShowersLow: 67
Slight Chance Showers And Thunderstorms then Chance Showers And ThunderstormsHigh: 77 Low: 70
SunnyHigh: 83 Low: 74
Chance Showers And ThunderstormsHigh: 84 Low: 74
Chance Showers And ThunderstormsHigh: 81 Low: 72
A slight chance of rain showers before 2am. Mostly cloudy, with a low around 67. West wind around 13 mph, with gusts as high as 18 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
A slight chance of showers and thunderstorms between 8am and 11am, then a chance of showers and thunderstorms between 11am and 2pm, then a chance of showers and thunderstorms. Partly sunny, with a high near 77. West wind 7 to 10 mph. Chance of precipitation is 40%. New rainfall amounts less than a tenth of an inch possible.
A slight chance of showers and thunderstorms before 8pm. Partly cloudy, with a low around 70. Northwest wind around 7 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
Sunny, with a high near 83. West wind 3 to 7 mph.
Mostly clear, with a low around 74. West wind 5 to 8 mph.
A chance of showers and thunderstorms after 8am. Sunny, with a high near 84. Chance of precipitation is 30%.
A chance of showers and thunderstorms. Partly cloudy, with a low around 74. Chance of precipitation is 30%.
A chance of showers and thunderstorms. Mostly sunny, with a high near 81. Chance of precipitation is 40%.
A chance of showers and thunderstorms. Mostly cloudy, with a low around 72. Chance of precipitation is 40%.
... An upper level disturbance will cross the area tonight, then slowly drift into the western Atlantic on Thursday. High pressure will build over the southeastern United States Friday through the weekend. A cold front will approach from the Great Lakes and Pennsylvania early next week.
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Lee troughing has developed along the Blue Ridge, with plenty of insolation ongoing east of the Blue Ridge to the Delmarva. Meanwhile, between the Blue Ridge and the Appalachians (and west of there too), scattered-numerous showers and thunderstorms have developed, in response to height falls/shortwave energy. Mid level lapse rates meager, which has prevented these thunderstorms from becoming mature thus far. However, greater instability/low-level lapse rates resides to the east coincident with the greater heat along I-95. Therefore expect thunderstorms to strengthen as they progress east across the metro corridor.
CAM timing has been inconsistent thus far today. Based on extrapolation of present trends, it would appear as though the best timing along I-95 would be starting near the evening commute and continue past dark. Have highlighted this period in the database, but have lingering chance PoPs thereafter. Given inherent instability, thunderstorms will be capable of supporting strong downburst winds. There is enough shear and shortwave support for clusters to develop.
The trough axis will be crossing at night, so thunderstorm trends won't be purely diurnal. But, there will be a weakening trend after midnight. Nocturnal cooling won't be efficient, with lows in the 70s.
SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... Thursday still looks to be the cooler day, relatively speaking, due to the presence of the trough axis overhead. Anticipate cloudier conditions, with showers/thunderstorms possibly starting in the morning hours. Have the highest PoPs in the east, based on greater instability and lower heights. With the clouds/shower chances, highs limited in the upper 80s/lower 90s.
Low-level airmass warms appreciably on Friday. 850/925 hPa temps of 25/30 C respectively still look likely, which would result in surface temperatures in the upper 90s to around 100. This combined with humid air in place (dew points likely mixing into the upper 60s to around 70) would result in heat indices of 100 to 110 during the afternoon hours. Excessive Heat Watches may be needed for Friday into the weekend by tonight, especially given the prolonged nature of the threat of dangerous heat. Of note, the heat index in urban areas (i.e. DC/Baltimore) may not drop below 90 at night with high dew point air pooling near the tidal Potomac River/Baltimore Inner Harbor and ambient air temperatures holding in the lower 80s through the night. All of these factors point to a potentially dangerous heat event Friday through the upcoming weekend.
LONG TERM /SATURDAY THROUGH WEDNESDAY/... A high pressure system will remain in place over the weekend. A south to southwesterly flow will continue to advect in warm and moist air into our region. Temperatures during the day will hover in the mid to upper 90s to low 100s. Dew point temperatures this weekend will be in the upper 60s to mid 70s which combined with high temperatures will lead to Heat indexes above 100 with periods above 105 and possibly as high as 110. The high temps and dewpoints will lead to heat advisories for the weekend with the possibility that a heat warning may be needed especially if heat indexes reach over the 110 degrees mark. The high temps and moisture will create an environment favorable for pop up showers and thunderstorms due to high CAPE above 2000 and little to no inhibition. Some of these storms have the potential to be severe with the main threat being pulse severe storms creating gusty to damaging winds.
Monday into Tuesday, a cold front will move through out region from the west. Ahead of this boundary, temperatures will likely soar up into the mid 90s leading to another day that heat advisory may be needed. The heat and moisture ahead of the boundary will make the the environment favorable for thunderstorms and severe weather. Model CAPE has values above 1500 and 2000 which combined with lift provided by the frontal boundary will create conditions ideal for widespread thunderstorms and showers on Monday. Some of these storm could be strong to severe and produce damaging winds. There remains a lot of uncertainty on the timing of the boundary and some these storms could linger into Tuesday. Most model solutions are showing precipitation moving out of our region by Tuesday afternoon.