Washington: Today - Variable cloudiness, high in the 80s, low 65 to 70. The chance of rain is 20 percent through tonight. Winds will be southeasterly at 5 to 10 mph. Tuesday - Partly cloudy with a thunderstorm high in the 80s.

Maryland and Virginia: Today - Variable cloudiness with a chance of thunderstorms in the western portions, high in the 80s, low in the 60s. Tuesday - Variable cloudiness with showers and thunderstorms possible, high in the 80s.

Lower Potomac and Chesapeake Bay - Variable cloudiness. Visibility will be 5 miles or more. Winds will be southeasterly at 5 to 10 knots shifting to the south at 12 to 18 knots by afternoon. Waves will average 1 to 3 feet.

Extended Area Forecast for Wednesday through Friday - Partly cloudy with a chance of mainly afternoon and evening thundershowers. Highs will range from the mid 70s to low 80s, lows from the upper 50s to the 60s. Normal Washington temperatures are a high of 81 and a low of 62.

West Virginia: Today and Tuesday - Partly cloudy with scattered showers and thundershowers, high in the 80s, low in the 60s.

The National Weather Forecast - Scattered showers and thundershowers will spread across the eastern third of the nation form New England and the lower Great Lakes region, to southern Texas through the Gulf Coast. Rain will also spread across the northwestern corner of the nation from western Montana and Wyoming to the Pacific. Most of the Great Lakes region - the Plains and the Southwest to the California coast will have a sunny and warm day. Cool weather will go along with the rain in the Northwest. Northern New England will also be cool.

Almanac Data for today: The sun rises 6:46 a.m., sets 7:23 p.m., moon rises 3:33 p.m. Tides: high 3:03 a.m. and 3:35 p.m., low 10:20 a.m. and 10:32 p.m. High and low tides at the following locations may be obtained by subtracting the hours indicated from the hours above: Annapolis (3 1/2), Bloody Point Lighthouse (4 1/2), Deale, Md. (4 1/2), Colonial Beach (5 1/4), Norfolk (1), Virginia Beach (3/4), Solomons Island (6 1/4), Point Lookout (7).

The Council of Governments' Air Quality Index for yesterday showed the high reading in the Washington area during the 1 p.m. period was 23 for the pollutant, photochemical oxidants. Index values between 0 and 25 indicate good air quality. When the indes exceeds 100 the air is considered very unhealthy and individuals with lung, heart and eye ailments are urged to restrict their activity. The forecast for today indicates that the air quality will remain about the same.

The National Weather Service forecasts the Potomac River Stage at Little Falls should fall to near 3.0 feet today.(TABLE) Time(COLUMN)T.(COLUMN)H. 12 mid.(COLUMN)73(COLUMN)55 1 a.m.(COLUMN)73(COLUMN)46 2 a.m.(COLUMN)72(COLUMN)46 3 a.m.(COLUMN)71(COLUMN)48 4 a.m.(COLUMN)70(COLUMN)47 5 a.m.(COLUMN)68(COLUMN)51 6 a.m.(COLUMN)67(COLUMN)53 7 a.m.(COLUMN)67(COLUMN)51 8 a.m.(COLUMN)66(COLUMN)56 9 a.m.(COLUMN)67(COLUMN)61 10 a.m.(COLUMN)68(COLUMN)63 11 a.m.(COLUMN)70(COLUMN)64 12 noon(COLUMN)73(COLUMN)60 1 p.m.(COLUMN)75(COLUMN)58 2 p.m.(COLUMN)76(COLUMN)54 3 p.m.(COLUMN)78(COLUMN)54 4 p.m.(COLUMN)78(COLUMN)58 5 p.m.(COLUMN)79(COLUMN)62 6 p.m.(COLUMN)78(COLUMN)62 7 p.m.(COLUMN)76(COLUMN)67(END TABLE) Temperatures ending 8 a.m. (EDT) yesterday:(TABLE) City(COLUMN)H.(COLUMN)L. Albany(COLUMN)67(COLUMN)34 Albuquerque(COLUMN)91(COLUMN)59 Amarillo(COLUMN)87(COLUMN)66 Anchorage(COLUMN)55(COLUMN)42 Asheville(COLUMN)90(COLUMN)60 Atlanta(COLUMN)94(COLUMN)70 Atlantic City(COLUMN)73(COLUMN)62 Austin(COLUMN)88(COLUMN)75 Baltimore(COLUMN)85(COLUMN)61 Billings(COLUMN)83(COLUMN)56 Birmingham(COLUMN)96(COLUMN)69 Bismarck(COLUMN)87(COLUMN)60 Boise(COLUMN)81(COLUMN)55 Boston(COLUMN)65(COLUMN)47 Brownsville(COLUMN)86(COLUMN)76 Buffalo(COLUMN)67(COLUMN)49 Burlington, Vt.(COLUMN)57(COLUMN)41 Casper(COLUMN)87(COLUMN)54 Charleston, S.C.(COLUMN)91(COLUMN)76 Charleston, W.Va.(COLUMN)87(COLUMN)68 Charlotte(COLUMN)94(COLUMN)72 Cheyenne(COLUMN)81(COLUMN)52 Chicago(COLUMN)93(COLUMN)69 Cincinnati(COLUMN)88(COLUMN)64 Cleveland(COLUMN)80(COLUMN)64 Columbia, S.C.(COLUMN)96(COLUMN)73 Columbus(COLUMN)87(COLUMN)67 Dal.-Ft. Worth(COLUMN)91(COLUMN)70 Dayton(COLUMN)91(COLUMN)64 Denver(COLUMN)87(COLUMN)57 Des Moines(COLUMN)92(COLUMN)69 Detroit(COLUMN)79(COLUMN)63 Duluth(COLUMN)72(COLUMN)56 El Paso(COLUMN)90(COLUMN)67 Evansville(COLUMN)89(COLUMN)67 Fargo(COLUMN)86(COLUMN)59 Flagstaff(COLUMN)77(COLUMN)43 Great Falls(COLUMN)83(COLUMN)60 Hartford(COLUMN)67(COLUMN)37 Helena(COLUMN)82(COLUMN)60 Houston(COLUMN)82(COLUMN)74 Indianapolis(COLUMN)89(COLUMN)65 Jackson(COLUMN)92(COLUMN)68 Jacksonville(COLUMN)87(COLUMN)75 Kansas City(COLUMN)92(COLUMN)69 Las Vegas(COLUMN)97(COLUMN)72 Little Rock(COLUMN)91(COLUMN)73 Los Angeles(COLUMN)78(COLUMN)61 Louisville(COLUMN)90(COLUMN)67 Memphis(COLUMN)92(COLUMN)75 Miami Beach(COLUMN)87(COLUMN)79 Midland(COLUMN)84(COLUMN)65 Milwaukee(COLUMN)78(COLUMN)65 Nashville(COLUMN)91(COLUMN)72 New Orleans(COLUMN)83(COLUMN)74 New York(COLUMN)75(COLUMN)49 Norfolk(COLUMN)91(COLUMN)70 North Platte(COLUMN)88(COLUMN)61 Oklahoma City(COLUMN)85(COLUMN)70 Omaha(COLUMN)89(COLUMN)69 Orlando(COLUMN)93(COLUMN)76 Philadelphia(COLUMN)80(COLUMN)57 Phoenix(COLUMN)101(COLUMN)80 Pittsburgh(COLUMN)74(COLUMN)60 Portland, Me.(COLUMN)66(COLUMN)40 Portland, Ore.(COLUMN)69(COLUMN)55 Providence(COLUMN)66(COLUMN)43 Raleigh(COLUMN)96(COLUMN)68 Rapid City(COLUMN)87(COLUMN)65 Reno(COLUMN)67(COLUMN)48 Richmond(COLUMN)95(COLUMN)68 St. Louis(COLUMN)93(COLUMN)66 St. Prbg.-Tampa(COLUMN)90(COLUMN)78 Salt Lake City(COLUMN)89(COLUMN)71 San Antonio(COLUMN)88(COLUMN)74 San Diego(COLUMN)73(COLUMN)68 San Francisco(COLUMN)67(COLUMN)59 St. Ste. Marie(COLUMN)64(COLUMN)55 Seattle(COLUMN)65(COLUMN)55 Shreveport(COLUMN)91(COLUMN)70 Sioux Falls(COLUMN)90(COLUMN)70 Spokane(COLUMN)78(COLUMN)50 Syracuse(COLUMN)66(COLUMN)41 Topeka(COLUMN)92(COLUMN)66 Tucson(COLUMN)95(COLUMN)72 Tulsa(COLUMN)88(COLUMN)74 Washington(COLUMN)87(COLUMN)66 Wichita(COLUMN)86(COLUMN)66(END TABLE) Temperatures Abroad Yesterday(TABLE) City(COLUMN)Weather(COLUMN)Time(COLUMN)Temp. Aberdeen(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)64 Amsterdam(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)70 Ankara(COLUMN)pt. cldy(COLUMN)3 p.m.(COLUMN)64 Athens(COLUMN)cloudy(COLUMN)2 p.m.(COLUMN)77 Auckland(COLUMN)clear(COLUMN)midnight(COLUMN)55 Berlin(COLUMN)rain(COLUMN)1 p.m.(COLUMN)59 Birmingham(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)75 Bonn(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)48 Brussels(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)64 Casablanca(COLUMN)clear(COLUMN)noon(COLUMN)77 Copenhagen(COLUMN)rain(COLUMN)1 p.m.(COLUMN)59 Dublin(COLUMN)drizzle(COLUMN)1 p.m.(COLUMN)68 Geneva(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)72 Hong Kong(COLUMN)pt. cldy.(COLUMN)8 p.m.(COLUMN)82 Jerusalem(COLUMN)clear(COLUMN)2 p.m.(COLUMN)84 Lisbon(COLUMN)clear(COLUMN)noon(COLUMN)86 London(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)75 Nice(COLUMN)clear(COLUMN)1 p.m.(COLUMN)77 Paris(COLUMN)clear(COLUMN)1 p.m..(COLUMN)72 Peking(COLUMN)clear(COLUMN)8 p.m.(COLUMN)63 Rome(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)77 Saigon(COLUMN)cloudy(COLUMN)8 p.m.(COLUMN)81 Sofia(COLUMN)clear(COLUMN)2 p.m.(COLUMN)66 Stockholm(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)57 Sydney(COLUMN)pt. cldy.(COLUMN)10 p.m.(COLUMN)59 Tokyo(COLUMN)clear(COLUMN)9 p.m.(COLUMN)82 Tunis(COLUMN)clear(COLUMN)1 p.m.(COLUMN)82 Vienna(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)63 Warsaw(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)61(END TABLE) Temperatures (Western Hemisphere)(TABLE) City(COLUMN)Weather(COLUMN)High(COLUMN)Low Acapulco(COLUMN)rain(COLUMN)88(COLUMN)75 Barbados(COLUMN)fair(COLUMN)86(COLUMN)77 Bermuda(COLUMN)fair(COLUMN)83(COLUMN)76 Bogota(COLUMN)cloudy(COLUMN)68(COLUMN)46 Calgary(COLUMN)cloudy(COLUMN)68(COLUMN)48 Culiacan(COLUMN)cloudy(COLUMN)95(COLUMN)78 Edmonton(COLUMN)pt. cldy.(COLUMN)66(COLUMN)48 Kingston(COLUMN)fair(COLUMN)90(COLUMN)80 Montego Bay(COLUMN)fair(COLUMN)88(COLUMN)75 Mexico City(COLUMN)haze(COLUMN)75(COLUMN)58 Monterrey(COLUMN)cloudy(COLUMN)92(COLUMN)74 Montreal(COLUMN)cloudy(COLUMN)59(COLUMN)39 Nassau(COLUMN)showers(COLUMN)90(COLUMN)74 Ottawa(COLUMN)cloudy(COLUMN)59(COLUMN)43 Regina(COLUMN)clear(COLUMN)82(COLUMN)54 St. Kitts(COLUMN)fair(COLUMN)92(COLUMN)77 Toronto(COLUMN)rain(COLUMN)66(COLUMN)75 Vancouver(COLUMN)cloudy(COLUMN)64(COLUMN)54 Veracruz(COLUMN)cloudy(COLUMN)85(COLUMN)74 Winnipeg(COLUMN)pt. cldy.(COLUMN)81(COLUMN)52(END TABLE)