Washington: Today - Partly cloudy, warm and humid with a chance of afternoon or evening thundershowers, high near 90, low 65 to 70. The chance of rain is 30 percent through tonight. Winds will be light and variable. Tuesday - Partly cloudy, warm and humid, high near 90.

Maryland and Virginia: Today and Tuesday - Partly cloudy, warm and humid with a chance of scattered showers and thundershowers, high in the 80s to low 90s, low in the 60s.

Extended Area Forecast for Wednesday through Friday - Partly cloudy and warm through the period Highs will range from the are a high of 79 and a low of 59, 80s to low 90s, lows in the 60s. Normal Washington temperatures.

Lower Potomac and Chesapeake Bay - Cloudy with a chance of afternoon thunderstorms. Visibility will be 5 miles or more diminishing to less than 1 mile in rain. Winds will be from the southeast at 8 to 12 knots. Waves will average 1 foot or less.

The National Weather Forecast for Today - Showers and Thunderstorms will extend from the northern and central Plateau across the northern and central Plains, the Great Lakes and portions of the Ohio Valley to the East Coast from New Jersey to southern New England. Snow is likely in higher elevations in the northern and central Plateau and Rockies. There will be widely scattered showers along the Gulf Coast through Florida and in the Tennessee Valley area. Skies will be mostly sunny over California and the Carolinas. Temperatures will be warm from the southern Plains across the lower and middle Mississippi valley to the Atlantic Coast from Florida to Virginia. Mild to cool temperatures will prevail through most of the remainder of the nation.

The Council of Government's Air Quality Index for yesterday showed the high reading in the Washington area during the 1 p.m. period was 50 for the pollutant, photochemical oxidamts. Index values between 50 and 99 indicate unhealthy air quality. When the index exceeds 100 the air in 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 improve.

The National Weather Service forecasts the Potomac River stage at Little Falls should remain near 3.0 feet today.

Almanac Data for today: The sun rises 6:52 a.m., sets 7:12 p.m.; moon rises 8:31 p.m., sets 8:46 a.m. Tides: high 9:12 a.m. and 9:40 p.m. low 3:30 a.m. and 3:51 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 1/4), Solomons Island (6 1/4), Point Lookout (7).

Washington data for yesterday: Highest temperature since midnight yesterday, 86 degrees at 2:02 p.m. Lowest temperature since midnight, 69 degrees at 5:30 a.m. Excess of temperature since Sept. 1, 73 degrees. Excess of temperature since Jan. 1, 71 degrees. Record high temperature for today, 91 degrees in 1927. Record low temperature for today, 45 degrees in 1937. Relative humidity: maximum, 84 percent at 6 a.m.; minimum, 52 percent at 2 p.m., 24 hour precipitation, none. Deffciency of precipitation since Sept. 1, .94 inches. Excess of precipitation since Jan. 1, 2.71 inches. Highest observed wind since 8 a.m., 13 miles per hour from the southeast at 6:53 p.m. Peak gust since 8 a.m., 17 miles per hour from the southeast at 6:46 p.m. Local Temps, Humidity(TABLE) Time(COLUMN)T.(COLUMN)H. 12 midnite(COLUMN)74(COLUMN)71 1 a.m.(COLUMN)73(COLUMN)74 3 a.m.(COLUMN)72(COLUMN)76 4 a.m.(COLUMN)70(COLUMN)81 5 a.m.(COLUMN)70(COLUMN)81 6 a.m.(COLUMN)69(COLUMN)84 7 a.m.(COLUMN)69(COLUMN)84 8 a.m.(COLUMN)71(COLUMN)79 9 a.m.(COLUMN)74(COLUMN)71 10 a.m.(COLUMN)78(COLUMN)62 11 a.m.(COLUMN)81(COLUMN)57 12 noon(COLUMN)82(COLUMN)57 1 p.m.(COLUMN)83(COLUMN)55 2 p.m.(COLUMN)85(COLUMN)52 3 p.m.(COLUMN)84(COLUMN)61 4 p.m.(COLUMN)86(COLUMN)59 5 p.m.(COLUMN)86(COLUMN)57 6 p.m.(COLUMN)84(COLUMN)68 7 p.m.(COLUMN)82(COLUMN)70(END TABLE) Temperatures ending 8 a.m. (EDT) yesterday(TABLE) City(COLUMN)H.(COLUMN)L. Albany(COLUMN)72(COLUMN)41 Albuquerque(COLUMN)89(COLUMN)54 Amarillo(COLUMN)97(COLUMN)72 Anchorage(COLUMN)60(COLUMN)42 Asheville(COLUMN)84(COLUMN)61 Atlanta(COLUMN)88(COLUMN)68 Atlantic City(COLUMN)73(COLUMN)62 Austin(COLUMN)90(COLUMN)76 Baltimore(COLUMN)86(COLUMN)63 Billings(COLUMN)68(COLUMN)45 Birmingham(COLUMN)87(COLUMN)70 Bismarck(COLUMN)67(COLUMN)40 Boise(COLUMN)64(COLUMN)34 Boston(COLUMN)77(COLUMN)55 Brownsville(COLUMN)93(COLUMN)77 Buffalo(COLUMN)69(COLUMN)50 Burlington, Vt.(COLUMN)70(COLUMN)38 Casper(COLUMN)77(COLUMN)43 Charleston, S.C.(COLUMN)86(COLUMN)75 Charleston, W.Va.(COLUMN)81(COLUMN)65 Charlotte(COLUMN)85(COLUMN)66 Cheyenne(COLUMN)79(COLUMN)53 Chicago(COLUMN)75(COLUMN)68 Cincinnati(COLUMN)84(COLUMN)69 Cleveland(COLUMN)75(COLUMN)62 Columbia, S.C.(COLUMN)92(COLUMN)70 Columbus(COLUMN)80(COLUMN)67 Dal.-Ft. Worth(COLUMN)98(COLUMN)77 Dayton(COLUMN)81(COLUMN)69 Denver(COLUMN)86(COLUMN)61 Des Moines(COLUMN)89(COLUMN)59 Detroit(COLUMN)77(COLUMN)59 Duluth(COLUMN)54(COLUMN)42 El Paso(COLUMN)91(COLUMN)69 Evansville(COLUMN)79(COLUMN)71 Fairbanks(COLUMN)46(COLUMN)45 Fargo(COLUMN)70(COLUMN)42 Flagstaff(COLUMN)72(COLUMN)36 Great Falls(COLUMN)58(COLUMN)31 Hartford(COLUMN)77(COLUMN)45 Helena(COLUMN)60(COLUMN)32 Houston(COLUMN)91(COLUMN)77 Indianapolis(COLUMN)86(COLUMN)70 Jackson(COLUMN)92(COLUMN)70 Jacksonville(COLUMN)86(COLUMN)66 Juneau(COLUMN)59(COLUMN)34 Kansas City(COLUMN)97(COLUMN)66 Las Vegas(COLUMN)91(COLUMN)64 Little Rock(COLUMN)92(COLUMN)72 Los Angeles(COLUMN)77(COLUMN)65 Louisville(COLUMN)85(COLUMN)70 Memphis(COLUMN)90(COLUMN)76 Miami Beach(COLUMN)84(COLUMN)81 Midland(COLUMN)94(COLUMN)73 Milwaukee(COLUMN)67(COLUMN)63 Mpls.-St. Paul(COLUMN)69(COLUMN)49 Nashville(COLUMN)85(COLUMN)69 New Orleans(COLUMN)88(COLUMN)72 New York(COLUMN)80(COLUMN)59 Norfolk(COLUMN)90(COLUMN)69 North Platte(COLUMN)78(COLUMN)47 Oklahoma City(COLUMN)101(COLUMN)78 Omaha(COLUMN)82(COLUMN)56 Orlando(COLUMN)91(COLUMN)72 Philadephia(COLUMN)86(COLUMN)62 Phoenix(COLUMN)97(COLUMN)71 Pittsburgh(COLUMN)78(COLUMN)65 Portland, Me.(COLUMN)77(COLUMN)47 Portland, Ore.(COLUMN)67(COLUMN)45 Providence(COLUMN)77(COLUMN)53 Raleigh(COLUMN)87(COLUMN)65 Rapid City(COLUMN)71(COLUMN)52 Reno(COLUMN)79(COLUMN)46 Richmond(COLUMN)90(COLUMN)65 St. Louis(COLUMN)83(COLUMN)75 St. Prbg.-Tampa(COLUMN)88(COLUMN)72 Salt Lake City(COLUMN)77(COLUMN)55 San Antonio(COLUMN)89(COLUMN)76 San Diego(COLUMN)72(COLUMN)68 San Francisco(COLUMN)69(COLUMN)56 San Juan(COLUMN)91(COLUMN)78 St. Ste. Marie(COLUMN)60(COLUMN)48 Seattle(COLUMN)63(COLUMN)46 Shreveport(COLUMN)90(COLUMN)73 Sioux Falls(COLUMN)73(COLUMN)44 Spokane(COLUMN)60(COLUMN)40 Syracuse(COLUMN)71(COLUMN)47 Topeka(COLUMN)101(COLUMN)65 Tucson(COLUMN)93(COLUMN)63 Tulsa(COLUMN)102(COLUMN)79 Washington(COLUMN)87(COLUMN)69 Wichita(COLUMN)105(COLUMN)48(END TABLE) Temperatures Abroad Yesterday(TABLE) City(COLUMN)Weather(COLUMN)Time(COLUMN)Temp Aberdeen(COLUMN)clear(COLUMN)1 p.m.(COLUMN)59 Amsterdam(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)61 Ankara(COLUMN)rain(COLUMN)3 p.m.(COLUMN)55 Athens(COLUMN)pt. cldy.(COLUMN)2 p.m.(COLUMN)77 Auckland(COLUMN)clear(COLUMN)midnight(COLUMN)52 Berlin(COLUMN)drizzle(COLUMN)1 p.m.(COLUMN)61 Birmingham(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)61 Bonn(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)59 Brussels(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)63 Casablanca(COLUMN)cloudy(COLUMN)noon(COLUMN)75 Copenhagen(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)59 Dublin(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)59 Geneva(COLUMN)clear(COLUMN)1 p.m.(COLUMN)70 Hong Kong(COLUMN)pt. Cldy.(COLUMN)8 p.m.(COLUMN)84 Jerusalem(COLUMN)pt. cldy.(COLUMN)2 p.m.(COLUMN)75 Lisbon(COLUMN)pt. cldy.(COLUMN)noon(COLUMN)79 London(COLUMN)clear(COLUMN)1 p.m.(COLUMN)64 Madrid(COLUMN)clear(COLUMN)1 p.m.(COLUMN)86 Malta(COLUMN)clear(COLUMN)1 p.m.(COLUMN)82 Manila(COLUMN)cloudy(COLUMN)3 p.m.(COLUMN)77 Moscow(COLUMN)cloudy(COLUMN)3 p.m.(COLUMN)57 New Delhl(COLUMN)pt. cldy.(COLUMN)5 p.m.(COLUMN)93 Nice(COLUMN)clear(COLUMN)1 p.m.(COLUMN)73 Oslo(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)61 Paris(COLUMN)clear(COLUMN)1 p.m.(COLUMN)68 Peking(COLUMN)cloudy(COLUMN)8 p.m.(COLUMN)64 Rome(COLUMN)clear(COLUMN)1 p.m.(COLUMN)79 Sofia(COLUMN)pt. cldy.(COLUMN)2 p.m.(COLUMN)63 Stockholm(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)61 Sydney(COLUMN)clear(COLUMN)10 p.m.(COLUMN)61 Tokyo(COLUMN)cloudy(COLUMN)9 p.m.(COLUMN)77 Tunis(COLUMN)clear(COLUMN)1 p.m.(COLUMN)81 Vienna(COLUMN)clear(COLUMN)1 p.m.(COLUMN)75 Warsaw(COLUMN)clear(COLUMN)1 p.m.(COLUMN)68(END TABLE) Temperatures (Western Hemisphere)(TABLE) City(COLUMN)Weather(COLUMN)High(COLUMN)Low Acapulco(COLUMN)sunny(COLUMN)90(COLUMN)77 Barbados(COLUMN)pt. cldy.(COLUMN)88(COLUMN)81 Bermuda(COLUMN)pt. cldy.(COLUMN)82(COLUMN)73 Mexico City(COLUMN)sunny(COLUMN)77(COLUMN)54 Monterrey(COLUMN)pt. cldy.(COLUMN)94(COLUMN)75 Nassau(COLUMN)pt. cldy.(COLUMN)88(COLUMN)75 St. Kitts(COLUMN)pt. cldy.(COLUMN)91(COLUMN)76 Vera Cruz(COLUMN)pt. cldy.(COLUMN)93(COLUMN)73 (END TABLE)