... High pressure will settle to the south of our area through tonight. A cold front will approach late Tuesday into Tuesday night and remain stalled near our area through the end of the week.
NEAR TERM /THROUGH TONIGHT/... Aside from a few mid-level cumulus near Highland County in Virginia, the entire region has few to no clouds as of 10am. As we venture into the afternoon, additional cumulus clouds will develop across the region with the earlier development expected to be along the Blue Ridge Mountains due to daytime differential heating. Our afternoon will be warm one with high temperatures reaching the lower to middle 90s. This heating, along with moisture in place of dewpoint temperatures in the lower to middle 70s will spark a couple of isolated to widely scattered showers and thunderstorms. Any part of our CWA could encounter a shower or thunderstorm will possible early development in the Potomac Highlands and along the central Blue Ridge Mountains. Heat indice values will reach the upper 90s and low 100s.
Dry conditions expected tonight after early evening showers and thunderstorms dissipate and weak high pressure builds overhead. Fog could develop again late tonight.
SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... Southerly flow will continue on Tuesday ahead of an approaching boundary as high pressure remains centered over the western Atlantic. Warm and moist air advection will again allow for heat index values to reach the upper 90s, maybe a few areas in the triple digits. Shortwave energy aloft and diurnal heat will allow for another day of afternoon and evening showers and thunderstorms as the front continues to approach our area. Drier conditions on Tuesday night.
On Wednesday, the surface boundary continues to move into our region and stalls into Wednesday night near our area. Shortwave stalls near the Ohio Valley while pulses of shortwave energy move into our region. Chances for showers and thunderstorms will increase on Wednesday, with chance of precip remaining into the nighttime hours. Heat index values again will reach the upper 90s and maybe the low 100s as we remain under southerly flow.
LONG TERM /WEDNESDAY THROUGH SUNDAY/... Guidance remains in relatively good agreement regarding the progression of weather features late this week. On Thursday, a cold front will be stalling out just north of our region. A weak upper low will be centered near Omaha and another low will be near the Carolina coast. The front will remain nearly stationary through Sunday, though will drop a bit further south Saturday. The upper disturbance near the Carolina coast will move north and then east, into the open Atlantic, while the low near Omaha will move towards Detroit by Sunday.
This pattern will result in gradually diminishing temperatures as clouds and shower/t-storm chances increase, with highs in the upper 80s Thursday dropping into the low-mid 80s Friday-Sunday. There will be a modest severe weather risk along with at least a marginal flood risk. This may be enhanced by tropical moisture injected into the region by the disturbance that will be along the Carolina coast on Thursday.