Showers, Storms, Some Severe?

Now

** Severe Thunderstorm Watch in effect until 8 PM **

Showers and possible thunderstorms. Clouds increased this afternoon as showers and thunderstorms approached ahead of a cold front through the upper Ohio Valley. The rainfall promises a chance of at least some relief to areas running at least 50% below average for precipitation in the last 30 days.

Temperatures reached the low 80s in most places before the clouds moved in, with a high of 83° at both National and Dulles by 2pm. With the onset of rain, temperatures quickly dropped to the low 70s at Dulles. Following the frontal passage, much cooler temperatures will prevail for the next couple of days.

NWS experimental precipitation analysis shows most of the DC region at less than 50% of normal precipitation (orange) for the 30 days through this morning. Some areas, particularly in Northern Virginia, are less than 25% of normal (red).

Tonight and Tomorrow

Showers and thunderstorms ending, cooler. The heaviest activity has now moved east of the District, but some showers and isolated thunderstorms could still persist through 7-8pm, followed by some clearing by morning. Lows will be in the low to mid 50s. Tomorrow will be mostly sunny with lower humidity and highs 68-72°

For the outlook through the weekend, scroll on down to Dan's post below.

Tropical Topics

Eastern Pacific hurricane season officially began yesterday.

Science Daily reported yesterday on some new research from NASA's Goddard Space Flight Center in Greenbelt on the role of air flow in a hurricane's eye for storm intensification. The results, which appear in the June issue of the American Meteorological Society's Journal of the Atmospheric Sciences, indicate that interaction between the eye and the eyewall, previously considered insignificant, plays a crucial role in the operation of the hurricane's heat engine.