Latest radar images from Sterling, VA reveal some very isolated showers moving in a general northwest direction towards the DC metro region. With this in mind, a small chance (40%) for showers exists through the day today.

The Numerical Weather models have now come into very good agreement regarding the late week rain event. This now looks like a significant rainfall event for the entire eastern seaboard with rainfall totals approaching 3-5" possible in some locations. Obviously, this event has the potential to wash out, or at least eat into a significant amount of our drought. Showers will increase steadily overnight into tomorrow morning as a tropical low to the south in the Gulf of Mexico merges with a strong cold front approaching the region from the northwest.

There is some timing disagreement between the two 'powerhouse' computer models, the GFS (Global Forecast System) and the NAM (North American Mesoscale). The NAM keeps the runs the heaviest precip through the region Saturday afternoon, as opposed to the GFS bringing the heavy stuff through early Saturday.

GFS model precip forecast showing nearly 4" of rainfall accumulation through the Weekend

NCEP Models

Either way, rainfall has the potential to be significant across the region, and some gusty winds up to 30-40 mph are possible as the lows/cold front lift away to the northeast.

With regards as to how Sunday shapes up, it looks like yet another trailing tropical low may work its way up the coast and at least keep the cloud cover fairly thick over the region. A 30% chance of precip will accompany this system and details will be worked out later on.