Breaking the Spell of the Muggies

5:25 Update: The storm moving into Fairfax Co. has prompted a Special Marine Warning for the tidal Potomac.

Now

Muggy, chance of showers: Temperatures throughout the Washington DC region are in the low 90s and higher late this afternoon. The thunderstorms which awoke many residents early this morning have added to the mugginess; nearly all locations are reporting heat index values over 100. Relief is on the way, however, in the form of a cold front moving southeastward from the Great Lakes. Ahead of the front, radar is showing only a couple of extremely isolated thunderstorms from near Hagerstown to west of Charlottesville. One of them in southern Loudoun County is intensifying and moving slowly eastward into Fairfax County at post time.

CapitalWeather.com chart from NWS data, photo by Kevin Ambrose

Tonight and Tomorrow

Becoming cooler and less humid:There is still a 40% chance of thunderstorms through around midnight, but the timing of the frontal passage is looking unfavorable for any widespread activity. Lows should be mainly in the mid 70s. Tomorrow will be cooler and much less humid with highs about 88.

Scroll down to Jason's post below for the outlook through the rest of the week.

Tropical Topics

Tropical Storm Chris is now history, but the National Hurricane Center is watching a "well-defined" low pressure area about 1200 miles east of the southern Windward Islands for possible development into a tropical depression later today or tomorrow.

Today's WaPo has an article, "Research Team Seeking Clues to a Hurricane's Birth", about the NAMMA project, a joint study between NASA and NOAA's Hurricane Research Division, which is celebrating its 50th anniversary this year. The experiment is designed to help understand the process by which easterly waves, disturbances which move off the African continent, become tropical cyclones in the eastern Atlantic.