Washington: Today - Partly cloudy and humid, highs near 90, lows near 70. Chance of rain 30 per cent through tonight. Wednesday - Partly, cloudy with chance of rain, highs near 90.

Maryland and Virginia: Today - Rain, highs in mid to upper 80s, lows in 60s. Wednesday - Rain, highs in mid to upper 80s.

Lower Potomac and Chesapeake Bay: Today - Fair skies and good visibility through tonight with chance of afternoon and evening showers. Winds should be variable at 5 knots or less this morning, southerly at up to 14 knots this afternoon and variable at 6 knots or less tonight.

Extended Area Outlook: For Thursday through Saturday - Chance of rain Thursday followed by fair skies and slightly cooler temperatures through Saturday. Highs would average in 80s, lows in 60s through period. Washington's normal temperature range for this time of year is from 87 to 68.

Atlantic Ocean Beaches from Cape Bay to Cape Hatteras: Today and Wednesday - Partly cloudy with chance of afternoon and evening showers, highs in mid to upper 80s. Water temperatures should range from mid to upper 60s north to near 80 in south.

West Virginia: Today - Rain, highs in 80s, lows in 60s. Wednesday - rain, highs in 80s.

The National Weather Forecast for Today - Thundershowers are likely from the central Appalachians, the Great Lakes region and the Ohio Valley across the upper Mississippi Valley into eastern North Dakota. Scattered thunderstorms will be found from Florida across the Gulf Coast states and the mid and lower Mississippi Valley into the eastern south and central Plains. Other parts of the nation will be sunny. It will be hot in the mid Mississippi Valley and Wisconsin, in Georgia and South Carolina and from northeastern New York into northern Maine, in southwest Texas and the northern California and the southwestern Oregon coastal sections. Elsewhere it will be seasonably warm.

ALMANAC DATA FOR Tuesday, on the 27, 1977: Sun rises 5:45 a.m., sets 8:37 p.m.; moon rises 4:50 a.m., sets 2:40 a.m. Tides: High [WORD ILLEGIBLE] and 5:23 p.m., low 12:05 p.m. and 12:10 a.m. High and low tides at the following locations can be obtained by subtracting the hours indicated from the tides above. Annapolis (3 1/2); Bloody Point Lighthouse (4 1/2); Deale, Md. (4 1/2); Colonial Beach (6); Norfolk (1 1/2); Virginia Beach (1); Solomons Island (6 1/2); Point Lookout (7).

The Council of Governments' Air Quality Index for yesterday showed the high reading in the Washington area during the 2 to 3 p.m. period was 120 for the pollutant, photochemical oxidants. Index values between 100 and 249 indicate very unhealthy air quality. When the index exceeds 100 the air becomes hazardous and persons with lung, heart and eye problems should restrict their activity. The forecast for today indicates the air quality will improve slightly.

The National Weather Service forecasts that the Potomac River stage at Little Falls will remain near 2.9 feet through today.

Washington data at 8 p.m. (EDT) yesterday: Highest temperature since 8 a.m. yesterday, 91 degrees at 3:38 p.m. Lowest temperature since midnight, 69 degrees at 4:45 a.m. Deficiency of temperature since June 1, 21 degrees. Excess of temperature since Jan. 1, 187 degrees. Record high temperature for today, 100 degrees in 1969. Record low temperature for today, 54 degrees in 1927. Relative humidity: Maximum, 84 per cent at 6 a.m.; Minimum, 54 per cent at 4 p.m., 24 hour precipitation, none inches. Excess of precipitation since June 1, .16 inches. Deficiency of precipitation since Jan. 1, 6.06 inches. Highest observed wind since 8 a.m., 10 miles per hour from the S.E. at 7 p.m. Peak gust since 8 a.m., 16 miles per hour from the S.E. at 7:01 p.m. Local Temp., Humidity(TABLE) Time(COLUMN)T.(COLUMN)H. 12 mid.(COLUMN)79(COLUMN)64 1 a.m.(COLUMN)74(COLUMN)71 2 a.m.(COLUMN)73(COLUMN)74 3 a.m.(COLUMN)72(COLUMN)76 4 a.m.(COLUMN)71(COLUMN)79 5 a.m.(COLUMN)70(COLUMN)81 6 a.m.(COLUMN)69(COLUMN)84 7 a.m.(COLUMN)72(COLUMN)76 8 a.m.(COLUMN)76(COLUMN)69 9 a.m.(COLUMN)80(COLUMN)61 10 a.m.(COLUMN)83(COLUMN)55 11 a.m.(COLUMN)85(COLUMN)50 12 noon(COLUMN)87(COLUMN)47 1 p.m.(COLUMN)88(COLUMN)47 2 p.m.(COLUMN)89(COLUMN)44 3 p.m.(COLUMN)87(COLUMN)45 4 p.m.(COLUMN)90(COLUMN)41 5 p.m.(COLUMN)88(COLUMN)44 6 p.m.(COLUMN)87(COLUMN)47(END TABLE) Temperatures, ending 9 a.m. (EST) yesterday:(TABLE) City(COLUMN)H.(COLUMN)L. Albany(COLUMN) 80(COLUMN)60 Albuquerque(COLUMN) 96(COLUMN)63 Amarillo(COLUMN) 91(COLUMN)68 Anchorage(COLUMN) 66(COLUMN)55 Asheville(COLUMN) 83(COLUMN)65 Atlanta(COLUMN) 90(COLUMN)68 Atlantic City(COLUMN) 84(COLUMN)65 Austin(COLUMN) 93(COLUMN)74 Baltimore(COLUMN) 88(COLUMN)62 Billings(COLUMN) 94(COLUMN)62 Birmingham(COLUMN) 92(COLUMN)71 Bismarck(COLUMN) 92(COLUMN)56 Boise(COLUMN) 92(COLUMN)58 Boston(COLUMN) 75(COLUMN)61 Brownsville(COLUMN) 91(COLUMN)75 Buffalo(COLUMN) 77(COLUMN)59 Burlington, Vt.(COLUMN) 78(COLUMN)61 Casper(COLUMN) 92(COLUMN)63 Ch'eston, S.C.(COLUMN) 93(COLUMN)75 C'lton, W.Va.(COLUMN) 83(COLUMN)65 Charlotte, N.C.(COLUMN) 87(COLUMN)69 Cheyenne(COLUMN) 88(COLUMN)61 Chicago(COLUMN) 90(COLUMN)71 Cincinnati(COLUMN) 84(COLUMN)67 Cleveland(COLUMN) 79(COLUMN)54 Columbia, S.C.(COLUMN) 92(COLUMN)71 Columbus, Ohio(COLUMN) 87(COLUMN)61 Dal.-Ft. Worth(COLUMN) 98(COLUMN)76 Dayton(COLUMN) 87(COLUMN)64 Denver(COLUMN) 94(COLUMN)65 Des Monies(COLUMN) 92(COLUMN)69 Detroit(COLUMN) 88(COLUMN)59 Duluth(COLUMN) 86(COLUMN)64 El Paso(COLUMN)101(COLUMN)70 Fairbanks(COLUMN) 70(COLUMN)53 Fargo(COLUMN) 91(COLUMN)61 Flagstaff(COLUMN) 82(COLUMN)49 Great Falls(COLUMN) 90(COLUMN)55 Hartford(COLUMN) 86(COLUMN)61 Helena(COLUMN) 87(COLUMN)52 Honolulu(COLUMN) 88(COLUMN)75 Houston(COLUMN) 94(COLUMN)78 Indianapolis(COLUMN) 87(COLUMN)70 Jackson, Miss.(COLUMN) 95(COLUMN)71 Jacksonville(COLUMN) 97(COLUMN)77 Juneau(COLUMN) 66(COLUMN)52 Kansas City(COLUMN) 87(COLUMN)67 Las Vegas(COLUMN)110(COLUMN)82 Little Rock(COLUMN) 83(COLUMN)68 Los Angeles(COLUMN) 79(COLUMN)60 Louisville(COLUMN) 87(COLUMN)72 Memphis(COLUMN) 90(COLUMN)73 Miami Beach(COLUMN) 87(COLUMN)79 Midland(COLUMN)101(COLUMN)71 Milwaukee(COLUMN) 84(COLUMN)66 Mpls.-St. Paul(COLUMN) 92(COLUMN)70 Nashville(COLUMN) 89(COLUMN)70 New Orleans(COLUMN) 94(COLUMN)75 New York(COLUMN) 85(COLUMN)66 Norfolk(COLUMN) 91(COLUMN)72 North Platte(COLUMN) 89(COLUMN)64 Oklahoma City(COLUMN) 86(COLUMN)70 Omaha(COLUMN) 94(COLUMN)69 Orlando(COLUMN) 92(COLUMN)74 Philadelphia(COLUMN) 84(COLUMN)62 Phoenix(COLUMN)108(COLUMN)81 Pittsburgh(COLUMN) 82(COLUMN)56 Portland, Me.(COLUMN) 68(COLUMN)55 Portland, Ore.(COLUMN) 82(COLUMN)52 Providence(COLUMN) 75(COLUMN)62 Raleigh(COLUMN) 90(COLUMN)66 Rapid City(COLUMN) 93(COLUMN)63 Reno(COLUMN) 96(COLUMN)58 Richmond(COLUMN) 96(COLUMN)68 St. Louis(COLUMN) 86(COLUMN)70 St. Prbg-Tampa(COLUMN) 95(COLUMN)81 Salt Lake City(COLUMN) 95(COLUMN)66 San Antonio(COLUMN) 91(COLUMN)76 San Diego(COLUMN) 76(COLUMN)61 San Francisco(COLUMN) 59(COLUMN)52 San Juan, P.R.(COLUMN) 88(COLUMN)74 St. Ste. Marle(COLUMN) 82(COLUMN)60 Seattle(COLUMN) 76(COLUMN)55 Shreveport(COLUMN) 92(COLUMN)71 Sioux Falls(COLUMN) 94(COLUMN)69 Spokane(COLUMN) 82(COLUMN)52 Syracuse(COLUMN) 76(COLUMN)55 Topeka(COLUMN) 89(COLUMN)66 Tucson(COLUMN)102(COLUMN)72 Tulsa(COLUMN) 89(COLUMN)72 Washington(COLUMN) 91(COLUMN)69 Wichita(COLUMN) 89(COLUMN)70(END TABLE) Temperatures Abroad Yesterday(TABLE) City(COLUMN)Weather(COLUMN)Time(COLUMN)Temp. Aberdeen(COLUMN) cloudy(COLUMN)1 p.m.(COLUMN)59 Amsterdam(COLUMN) clear(COLUMN)1 p.m.(COLUMN)64 Ankara(COLUMN)pt. cloudy(COLUMN)3 p.m.(COLUMN)63 Athens(COLUMN) clear(COLUMN)2 p.m.(COLUMN)82 Berlin(COLUMN)pt. cloudy(COLUMN)1 p.m.(COLUMN)63 Brimingham(COLUMN) cloudy(COLUMN)1 p.m.(COLUMN)61 Brussels(COLUMN)pt. cloudy(COLUMN)1 p.m.(COLUMN)64 Cairo(COLUMN) clear(COLUMN)2 p.m.(COLUMN)96 Casablanca(COLUMN) clear(COLUMN) noon(COLUMN)75 Copenhagen(COLUMN) pt. cldy(COLUMN)1 p.m.(COLUMN)61 Dublin(COLUMN) drizzle(COLUMN)1 p.m.(COLUMN)59 Geneva(COLUMN) clear(COLUMN)1 p.m.(COLUMN)64 Hong Kong(COLUMN) pt. cldy(COLUMN)8 p.m.(COLUMN)84 Lisbon(COLUMN) pt. cldy(COLUMN) noon(COLUMN)82 London(COLUMN) cloudy(COLUMN)1 p.m.(COLUMN)64 Madrid(COLUMN) pt. cldy(COLUMN)1 p.m.(COLUMN)84 Malta(COLUMN) clear(COLUMN)1 p.m.(COLUMN)75 Moscow(COLUMN) cloudy(COLUMN)3 p.m.(COLUMN)73 New Delhi(COLUMN) pt. cldy(COLUMN)5 p.m.(COLUMN)91 Nice(COLUMN) clear(COLUMN)1 p.m.(COLUMN)77 Oslo(COLUMN) rain(COLUMN)1 p.m.(COLUMN)59 Paris(COLUMN)pt. cloudy(COLUMN)1 p.m.(COLUMN)68 Peking(COLUMN) rain(COLUMN)8 p.m.(COLUMN)68 Rome(COLUMN) clear(COLUMN)1 p.m.(COLUMN)79 Saigon(COLUMN) storm(COLUMN)8 p.m.(COLUMN)75 Sofia(COLUMN)pt. cloudy(COLUMN)2 p.m.(COLUMN)70 Stockholm(COLUMN) rain(COLUMN)1 p.m.(COLUMN)59 Tel Aviv(COLUMN) clear(COLUMN)2 p.m.(COLUMN)91 Tokyo(COLUMN) cloudy(COLUMN)9 p.m.(COLUMN)72 Tunis(COLUMN) clear(COLUMN)1 p.m.(COLUMN)84 Vienna(COLUMN) clear(COLUMN)1 p.m.(COLUMN)70 Warsaw(COLUMN) pt. cldy(COLUMN)1 p.m.(COLUMN)64(END TABLE) Temperatures (Western Hemisphere)(TABLE) City(COLUMN)Weather(COLUMN)High(COLUMN)Low Accapulco(COLUMN) sunny(COLUMN)93(COLUMN)77 - (COLUMN) fair(COLUMN)86(COLUMN)77 Bermuda(COLUMN)pt. cldy(COLUMN)81(COLUMN)72 Bogota(COLUMN) cloudy(COLUMN)64(COLUMN)40 Calgary(COLUMN) cloudy(COLUMN)75(COLUMN)45 Culiacan(COLUMN)pt. cldy(COLUMN)99(COLUMN) - Edmonton(COLUMN)pt. cldy(COLUMN)68(COLUMN)43 Montego Bay(COLUMN)pt. cldy(COLUMN)90(COLUMN)74 Mexico City(COLUMN) haze(COLUMN)77(COLUMN)55 Monterrey(COLUMN)pt. cldy(COLUMN)96(COLUMN)70 Montreal(COLUMN) clear(COLUMN)75(COLUMN)61 Nassau(COLUMN)pt. cldy(COLUMN)88(COLUMN)72 Ottawa(COLUMN) clear(COLUMN)81(COLUMN)59 Regina(COLUMN) storm(COLUMN)73(COLUMN)54 St. Kitts(COLUMN)pt. cldy(COLUMN)89(COLUMN)75 St. Thomas(COLUMN)pt. cldy(COLUMN)49(COLUMN)78 Toronto(COLUMN) clear(COLUMN)81(COLUMN)55 Vancouver(COLUMN) clear(COLUMN)66(COLUMN)50 Veracruz(COLUMN) fair(COLUMN)88(COLUMN)74 Winnipeg(COLUMN) cloudy(COLUMN)77(COLUMN)50(END TABLE)