Per the National Weather Service:

* FROM LATE WEDNESDAY NIGHT INTO FRIDAY MORNING

* AN UPPER LEVEL LOW PRESSURE OVER THE WESTERN GREAT LAKES WILL
DROP SOUTHWARD INTO THE OHIO VALLEY WEDNESDAY INTO THURSDAY. AS
THE UPPER LOW DROPS SOUTHWARD...LOW LEVEL FLOW IS FORECAST TO
RAPIDLY INCREASE OVER THE AREA WEDNESDAY NIGHT RESULTING IN
SIGNIFICANT MOISTURE TRANSPORT INTO THE AREA. PERIODS OF HEAVY
RAINFALL ARE ANTICIPATED LATE WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT ACROSS THE CENTRAL MID-ATLANTIC. THE PERIOD OF MOST
INTENSE RAINFALL IS EXPECTED LATE WEDNESDAY NIGHT THROUGH EARLY
THURSDAY AFTERNOON. WIDESPREAD RAINFALL AMOUNTS OF 3 TO 5 INCHES
ARE EXPECTED WITH LOCALIZED HIGHER TOTALS IN AREAS OF REPEATED
ACTIVITY. EASTERN SLOPES OF MOUNTAINS SUCH AS THE NORTHERN BLUE
RIDGE AND CATOCTIN MOUNTAIN ALSO HAVE AN INCREASED RISK FOR
HIGHER RAIN TOTALS.

* POTENTIAL EXISTS FOR FLASH FLOODING OF SMALL STREAMS...CREEKS
AND URBAN AREAS ESPECIALLY IN AREAS OF REPEATED ACTIVITY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.