Washington: Today - Partly cloudy, warm and humid with a chance of mainly afternoon and evening thundershowers, high near 90, low in the 60s. The chance of rain is 30 percent diminishing to 10 percent tonight. Winds will be southwesterly at 10 mph or less through today. Tues - Sunday and pleasant, high in the 80s.

Maryland and Virginia: Today - Partly cloudy, warm and humid, high in the 80s to low 90s, low in the mid 50s to near 70. Tuesday - Sunny, high from the mid 70s to mid 80s.

Extended Area Forecast for Wednesday through Friday - Fair Wednesday. Partly cloudy and warmer Thursday and Friday, with a chance of thunderstorms. Highs will be in the 80s, lows in the 60s.

Lower Potomac and Chesapeake Bay - partly cloudy with a chance of afternoon and evening thundershowers, clearing tonight. Winds will be from the southwest at less than 10 knots. Visibility will be 5 miles or more diminishing to less than 1 mile in morning haze and later showers. Waves will average near 2 feet.

Atlantic Ocean Beaches from New Jersey to North Carolina: Today - Partly cloudy, warm and humid with a chance of afternoon and evening thundershowers, high near 90. Tuesday - Sunny and pleasant, high in the 80s. Water temperatures will range from the upper 60s in the north to the mid 70s in the south.

West Virginia: Today - Occasional showers ending during the day, highs from the mid 70s to mid 80s lows in the 50s and 60s. Tuesday - Sunny, highs from the upper 70s to mid 80s.

The National Weather Forecast for today - Thunderstorms will reach from New England across the lower Great Lakes region, the upper Ohio Valley and the mid Atlantic Coast states. Scattered or widely scattered thundershowers will be developing over the south Atlantic and eastern Gulf Coast states, the lower Mississippi and the Tennessee Valley into Missouri, Oklahoma and the central Great Plains. Others showers will be isolated over the Rockies and the northern Intermountain Region. Showers will also spread across the Pacific Northwest. Elsewhere sunny skies will dominate. Cooler temperatures will move over New England, the Ohio Valley and the southern half of the Great Lakes region. Mild weather will remain from the Pacific Northwest across the northern Great Plains and the northern half of Great Lakes region. The rest of the country will be warm.

The Council of Governments' Air Quality Index for yesterday showed the high reading in the Washington area during the 1 p.m. period was 48 for the pollutant, photochemical oxidants. Index values between 25 and 49 indicate fair air quality. When the index 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 deteriorate.

The National Weather Service forecasts the Potomac River State at Little Falls should remain 4.0 feet today.

Almanac Data for today: The sun rises 5:51 a.m., sets 8:35 p.m.; moon rises 10:44 a.m., sets 11:29 p.m. Tides: high 11:57 a.m. and 6:57 p.m., low 6:38 a.m. High and low tides at the following locations may be obtained by subtracting the hours indicated from the hours above: Annapolis (3 1/4), 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). Local Temps., Humidity(TABLE) Time(COLUMN)T.(COLUMN) . 12 midnight(COLUMN)76(COLUMN)85 1 a.m.(COLUMN)75(COLUMN)88 2 a.m.(COLUMN)75(COLUMN)88 3 a.m.(COLUMN)75(COLUMN)88 4 a.m.(COLUMN)74(COLUMN)90 5 a.m.(COLUMN)73(COLUMN)90 6 a.m.(COLUMN)73(COLUMN)87 7 a.m.(COLUMN)73(COLUMN)87 8 a.m.(COLUMN)75(COLUMN)85 9 a.m.(COLUMN)78(COLUMN)82 10 a.m.(COLUMN)79(COLUMN)82 11 a.m.(COLUMN)82(COLUMN)72 12 noon(COLUMN)85(COLUMN)68 1 p.m.(COLUMN)88(COLUMN)62 2 p.m.(COLUMN)89(COLUMN)62 3 p.m.(COLUMN)91(COLUMN)54 4 p.m.(COLUMN)91(COLUMN)52 5 p.m.(COLUMN)92(COLUMN)51 6 p.m.(COLUMN)91(COLUMN)51 7 p.m.(COLUMN)89(COLUMN)60(END TABLE) Temperatures ending 8 a.m. (EDT) yesterday:(TABLE) City(COLUMN)H.(COLUMN)L. Albany(COLUMN)88(COLUMN)70 Albuquerque(COLUMN)99(COLUMN)65 Amarillo(COLUMN)96(COLUMN)68 Anchorage(COLUMN)67(COLUMN)47 Asheville(COLUMN)87(COLUMN)59 Atlanta(COLUMN)90(COLUMN)69 Atlantic City(COLUMN)73(COLUMN)67 Austin(COLUMN)100(COLUMN)75 Baltimore(COLUMN)91(COLUMN)69 Billings(COLUMN)73(COLUMN)52 Birmingham(COLUMN)94(COLUMN)74 Bismarck(COLUMN)77(COLUMN)47 Boise(COLUMN)84(COLUMN)58 Boston(COLUMN)88(COLUMN)68 Brownsville(COLUMN)97(COLUMN)74 Buffalo(COLUMN)82(COLUMN)65 Burlington, Vt.(COLUMN)90(COLUMN)70 Casper(COLUMN)85(COLUMN)56 Charleston, S.C.(COLUMN)85(COLUMN)76 Charleston, W.V.(COLUMN)88(COLUMN)64 Charlotte(COLUMN)89(COLUMN)70 Cheyenne(COLUMN)87(COLUMN)54 Chicago(COLUMN)78(COLUMN)62 Cincinnati(COLUMN)87(COLUMN)66 Cleveland(COLUMN)86(COLUMN)60 Columbia, S.C.(COLUMN)93(COLUMN)68 Columbus(COLUMN)88(COLUMN)60 Dal.-Ft. Worth(COLUMN)102(COLUMN)75 Dayton(COLUMN)87(COLUMN)61 Denver(COLUMN)97(COLUMN)62 Des Moines(COLUMN)82(COLUMN)70 Detroit(COLUMN)79(COLUMN)57 Duluth(COLUMN)74(COLUMN)61 El Paso(COLUMN)100(COLUMN)69 Fairbanks(COLUMN)76(COLUMN)60 Fargo(COLUMN)70(COLUMN)51 Flagstaff(COLUMN)83(COLUMN)54 Great Falls(COLUMN)61(COLUMN)51 Hartford(COLUMN)89(COLUMN)68 Helena(COLUMN)71(COLUMN)53 Honolulu(COLUMN)86(COLUMN)73 Houston(COLUMN)96(COLUMN)80 Indianapolis(COLUMN)81(COLUMN)70 Jackson(COLUMN)96(COLUMN)76 Jacksonville(COLUMN)90(COLUMN)74 Juneau(COLUMN)66(COLUMN)52 Kansas City(COLUMN)96(COLUMN)67 Las Vegas(COLUMN)106(COLUMN)74 Little Rock(COLUMN)95(COLUMN)77 Los Angeles(COLUMN)85(COLUMN)58 Louisville(COLUMN)93(COLUMN)73 Memphis(COLUMN)94(COLUMN)81 Miami Beach(COLUMN)86(COLUMN)80 Midland(COLUMN)98(COLUMN)68 Milwaukee(COLUMN)74(COLUMN)61 Mpls.-St.Paul(COLUMN)75(COLUMN)67 Nashville(COLUMN)95(COLUMN)75 New Orleans(COLUMN)92(COLUMN)75 New York(COLUMN)85(COLUMN)72 Norfolk(COLUMN)89(COLUMN)71 North Platte(COLUMN)95(COLUMN)63 Oklahoma City(COLUMN)102(COLUMN)75 Omaha(COLUMN)80(COLUMN)69 Orlando(COLUMN)90(COLUMN)73 Philadelphia(COLUMN)89(COLUMN)71 Phoenix(COLUMN)108(COLUMN)84 Pittsburgh(COLUMN)83(COLUMN)62 Portland, Me.(COLUMN)87(COLUMN)61 Portland, Ore.(COLUMN)73(COLUMN)58 Providence(COLUMN)85(COLUMN)67 Raleigh(COLUMN)91(COLUMN)68 Rapid City(COLUMN)81(COLUMN)54 Reno(COLUMN)88(COLUMN)51 Richmond(COLUMN)93(COLUMN)69 St. Louis(COLUMN)92(COLUMN)73 St. Prbg.-Tampa(COLUMN)89(COLUMN)74 Salt Lake City(COLUMN)90(COLUMN)62 San Antonio(COLUMN)99(COLUMN)71 San Diego(COLUMN)75(COLUMN)66 San Francisco(COLUMN)67(COLUMN)54 San Juan(COLUMN)90(COLUMN)77 St. Ste. Marie(COLUMN)72(COLUMN)47 Seattle(COLUMN)68(COLUMN)56 Shreveport(COLUMN)101(COLUMN)74 Sioux Falls(COLUMN)76(COLUMN)60 Spokane(COLUMN)81(COLUMN)57 Syracuse(COLUMN)91(COLUMN)67 Topeka(COLUMN)95(COLUMN)73 Tucson(COLUMN)104(COLUMN)77 Tulsa(COLUMN)104(COLUMN)78 Washington(COLUMN)90(COLUMN)72 Wichita(COLUMN)103(COLUMN)80(END TABLE) Temperatures Abroad Yesterday(TABLE) City(COLUMN)Weather(COLUMN)Time(COLUMN)TemP. Aberdeen(COLUMN)clear(COLUMN)1 p.m.(COLUMN)61 Amsterdam(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)57 Ankara(COLUMN)clear(COLUMN)3 p.m.(COLUMN)95 Athens(COLUMN)clear(COLUMN)2 p.m.(COLUMN)86 Auckland(COLUMN)clear(COLUMN)midnight(COLUMN)4 Berlin(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)61 Birmingham(COLUMN)pt.cldy(COLUMN)1 p.m.(COLUMN)66 Bonn(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)59 Brussels(COLUMN)rain(COLUMN)1 p.m.(COLUMN)59 Cairo(COLUMN)clear(COLUMN)2 p.m.(COLUMN)102 Casablanca(COLUMN)clear(COLUMN)noon(COLUMN)77 Copenhagen(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)63 Dublin(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)63 Geneva(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)64 Hong Kong(COLUMN)clear(COLUMN)8 p.m.(COLUMN)84 Jerusalem(COLUMN)clear(COLUMN)2 p.m.(COLUMN)99 Lisbon(COLUMN)clear(COLUMN)noon(COLUMN)86 London(COLUMN)drizzle(COLUMN)1 p.m.(COLUMN)63 Madrid(COLUMN)clear(COLUMN)1 p.m.(COLUMN)90 Malta(COLUMN)clear(COLUMN)1 p.m.(COLUMN)77 Manila(COLUMN)pt.cldy.(COLUMN)8 p.m.(COLUMN)84 Moscow(COLUMN)pt.cldy.(COLUMN)3 p.m.(COLUMN)72 New Delhi(COLUMN)pt. cldy.(COLUMN)5 p.m.(COLUMN)86 Nice(COLUMN)clear(COLUMN)1 p.m.(COLUMN)72 Oslo(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)64 Paris(COLUMN)rain(COLUMN)1 p.m.(COLUMN)57 Peking(COLUMN)clear(COLUMN)8 p.m.(COLUMN)75 Rome(COLUMN)clear(COLUMN)1 p.m.(COLUMN)73 Saigon(COLUMN)cloudy(COLUMN)8 p.m.(COLUMN)84 Sofia(COLUMN)pt.cldy.(COLUMN)2 p.m.(COLUMN)72 Stockholm(COLUMN)rain(COLUMN)1 p.m.(COLUMN)57 Sydney(COLUMN)cloudy(COLUMN)10 p.m.(COLUMN)50 Tokyo(COLUMN)clear(COLUMN)9 p.m.(COLUMN)82 Tunis(COLUMN)clear(COLUMN)1 p.m.(COLUMN)81 Vienna(COLUMN)rain(COLUMN)1 p.m.(COLUMN)61 Warsaw(COLUMN)cloudy(COLUMN)10 p.m.(COLUMN)64(END TABLE) Temperatures (Western Hemisphere)(TABLE) City(COLUMN)Weather(COLUMN)High(COLUMN)Low Acapulco(COLUMN)cloudy(COLUMN)90(COLUMN)77 Barbados(COLUMN)pt.cldy(COLUMN)88(COLUMN)81 Bogota(COLUMN)cloudy(COLUMN)61(COLUMN)42 Calgary(COLUMN)cloudy(COLUMN)57(COLUMN)46 Edmonton(COLUMN)clear(COLUMN)68(COLUMN)41 Havana(COLUMN)pt.cldy.(COLUMN)89(COLUMN)75 Kingston(COLUMN)pt.cldy.(COLUMN)92(COLUMN)81 Montego Bay(COLUMN)pt.cldy.(COLUMN)88(COLUMN)74 Mexico City(COLUMN)haze(COLUMN)74(COLUMN)55 Monterrey(COLUMN)fair(COLUMN)101(COLUMN)73 Montreal(COLUMN)cloudy(COLUMN)88(COLUMN)66 Nassau(COLUMN)pt.cldy.(COLUMN)92(COLUMN)73 Ottawa(COLUMN)cloudy(COLUMN)84(COLUMN)63 Regina(COLUMN)clear(COLUMN)66(COLUMN)37 St. Kitts(COLUMN)pt.cldy.(COLUMN)88(COLUMN)77 St. Thomas(COLUMN)pt.cldy.(COLUMN)88(COLUMN)78 Toronto(COLUMN)clear(COLUMN)88(COLUMN)61 Vancouver(COLUMN)cloudy(COLUMN)68(COLUMN)55 Veracruz(COLUMN)pt.cldy.(COLUMN)88(COLUMN)75 Winnipeg(COLUMN)clear(COLUMN)61(COLUMN)48(END TABLE)