Washington: Today - Muggy, high near 90, low in mid 60s to mid 70s. Chance of rain 30 per cent through tonight. Tuesday - Muggy, high near 90.

Maryland and Virginia: Today - Muggy, highs in mid 80s to low 90s, lows in mid 60s to 70s.Chance of afternoon or evening showers. Today - Muggy, high near 90.

Lower Potomac and Chesapeake Bay: Today - Chance of rain in afternoon or evening with poor to good visibility through tonight. Winds should be easterly to south-easterly at up to 10 knots today becoming variable at about 5 knots tonight.

Extended Area OUtlook: For Wednesday through Friday - Humid through period with chance of rain Wednesday and Friday. Highs should range from mid 80s to mid 90s, lows from mid 60s to mid 70s through period. Washington's normal temperature range for this time or year is from 88 to 69.

Atlantic Ocean Beaches from Cape May through Maryland: Today and Tuesday - Partly cloudy with chance of afternoon and evening showers, highs near 80. Water temperatures should range from upper 60s to mid 70s.

Atlantic Ocean Beaches from Cape Hatteras through Virginia: Today and Tuesday - Partly cloudy with chance of afternoon and evening showers, highs in 80s. Water temperatures should be in mid to upper 70s.

West Virginia: Today - Rain, highs in mid 70s to mid 80s, lows in upper 60s to mid 70s. Tuesday - Rain, highs in 80s.

The National Weather Forecast for Today - Thunderstorms are likely from the lower Great Lakes through the Ohio Valley to Tennessee and the southern Appalachians and from North Dakota to western Wisconsin. There is a chance of scattered showers from the Mississppi Valley east to the Atlantic from the Great Lakes region and southern Pennsylvania south to the Gulf of Mexico. There is also a chance of scattered showers over the northern Plains and northern Rockies. Elsewhere, it will be mostly sunny. Temperatures are expected to be a few degrees cooler in the southeast with readings in the low 90s. Temperatures will be in the 90s in the Gulf Coast states the southern and central Plains and the southern plateau region. The only 100 degree temperatures expected will be in the desert southwest. It will be mild over the northern Rockies and in New England with temperatures in the upper 70s to low 80s. Elsewhere, it will be seasonably warm.

ALMANAC DATA FOR Monday, July 11, 1977. Sun rises 5:52 a.m., sets 8:35 p.m.; moon rises 2:24 a.m., sets 4:39 p.m. Tides: High 5:13 a.m. and 5:36 p.m. Low 12:07 p.m. and 12:15 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 Lighhouse (4 1/2); Deale, Md. (4 1/2); Colonia Beach (6); Norfolk (1 1/2); Virginia Beach (1); Solomons Island (6 1/2); Point Lookout (7).

The Council of Governments' Air stage Quality Index for yesterday showed the high reading in the Washington area during the 4 p.m. period was 135 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 National Weather Service forecasts that the Potomac River stage at Little Falls will remain near 2.7 feet through today. Local Temps., Humidity(TABLE) Time(COLUMN)T.(COLUMN)H. 12 mid.(COLUMN)80(COLUMN)72 1 a.m.(COLUMN)79(COLUMN)74 2 a.m.(COLUMN)78(COLUMN)79 3 a.m.(COLUMN)71(COLUMN)82 4 a.m.(COLUMN)76(COLUMN)88 5 a.m.(COLUMN)75(COLUMN)91 6 a.m.(COLUMN)75(COLUMN)91 7 a.m.(COLUMN)76(COLUMN)85 8 a.m.(COLUMN)79(COLUMN)79 9 a.m.(COLUMN)80(COLUMN)77 10 a.m.(COLUMN)84(COLUMN)67 11 a.m.(COLUMN)85(COLUMN)65 12 noon(COLUMN)86(COLUMN)63 1 p.m.(COLUMN)88(COLUMN)60 2 p.m.(COLUMN)90(COLUMN)54 3 p.m.(COLUMN)89(COLUMN)58 4 p.m.(COLUMN)91(COLUMN)54 5 p.m.(COLUMN)89(COLUMN)58 6 p.m.(COLUMN)86(COLUMN)61(END TABLE) Temperatures ending 8 a.m. (EDT) Yesterday(TABLE) City(COLUMN)H.(COLUMN)L. Albany(COLUMN)15(COLUMN)61 Albuquerque(COLUMN)10(COLUMN)18 Amarillo(COLUMN)86(COLUMN)67 Anchorage(COLUMN)72(COLUMN)65 Ashevville(COLUMN)50(COLUMN)64 Atlanta(COLUMN)64(COLUMN)67 Atlantic City(COLUMN)79(COLUMN)70 Austin(COLUMN)96(COLUMN)74 Baltimore(COLUMN)89(COLUMN)72 Billings(COLUMN)85(COLUMN)60 Birmingham(COLUMN)17(COLUMN)68 Bismarch(COLUMN)78(COLUMN)58 Boise(COLUMN)84(COLUMN)51 Boston(COLUMN)78(COLUMN)76 Brownsville(COLUMN)94(COLUMN)75 Buffalo(COLUMN)83(COLUMN)57 Burlington, Vt.(COLUMN)82(COLUMN)53 Casper(COLUMN)90(COLUMN)48 Charleston, S.C.(COLUMN)99(COLUMN)79 Chlstn., W.Va.(COLUMN)89(COLUMN)70 Charlotte, N.C.(COLUMN)100(COLUMN)70 Cheyenne(COLUMN)32(COLUMN)49 Chicago(COLUMN)79(COLUMN)64 Cincinnati(COLUMN)85(COLUMN)72 Cleveland(COLUMN)80(COLUMN)60 Columbia, S.C.(COLUMN)102(COLUMN)71 Columbus, Ohio(COLUMN)85(COLUMN)67 Dal-Ft. Worth(COLUMN)102(COLUMN)71 Dayton(COLUMN)88(COLUMN)69 Denver(COLUMN)87(COLUMN)58 Des Moines(COLUMN)84(COLUMN)65 Detroit(COLUMN)88(COLUMN)58 Duluth(COLUMN)68(COLUMN)49 El Paso(COLUMN)94(COLUMN)67 Fairbanks(COLUMN)79(COLUMN)60 Fargo(COLUMN)78(COLUMN)61 Flagstaff(COLUMN)87(COLUMN)50 Great Falls(COLUMN)82(COLUMN)54 Hartford(COLUMN)93(COLUMN)63 Helena(COLUMN)80(COLUMN)52 Honolulu(COLUMN)87(COLUMN)76 Houston(COLUMN)95(COLUMN)79 Indianapolis(COLUMN)89(COLUMN)73 Jackson, Miss.(COLUMN)88(COLUMN)72 Jacksonville(COLUMN)97(COLUMN)69 Juneau(COLUMN)70(COLUMN)54 Kansas City(COLUMN)84(COLUMN)66 Las Vegas(COLUMN)105(COLUMN)78 Little Rock(COLUMN)93(COLUMN)70 Las Angeles(COLUMN)79(COLUMN)62 Louisville(COLUMN)86(COLUMN)75 Memphis(COLUMN)92(COLUMN)75 Miami Beach(COLUMN)88(COLUMN)79 Midland(COLUMN)93(COLUMN)68 Milwaukee(COLUMN)73(COLUMN)55 Mpls-St. Paul(COLUMN)75(COLUMN)64 Nashville(COLUMN)90(COLUMN)73 New Orleans(COLUMN)91(COLUMN)74 New York(COLUMN)89(COLUMN)72 Norfolk(COLUMN)94(COLUMN)74 North Platte(COLUMN)85(COLUMN)60 Oklahoma City(COLUMN)91(COLUMN)68 Omaha(COLUMN)84(COLUMN)65 Orlando(COLUMN)94(COLUMN)74 Philadelphia(COLUMN)86(COLUMN)72 Phoenix(COLUMN)109(COLUMN)88 Pittsburgh(COLUMN)80(COLUMN)61 Portland, Me.(COLUMN)77(COLUMN)59 Portland, Ore.(COLUMN)67(COLUMN)51 Providence(COLUMN)87(COLUMN)68 Raleigh(COLUMN)100(COLUMN)69 Rapid City(COLUMN)82(COLUMN)58 Reno(COLUMN)33(COLUMN)42 Richmond(COLUMN)99(COLUMN)72 St. Louis(COLUMN)88(COLUMN)70 St. Prbg-Tampa(COLUMN)91(COLUMN)74 Salt Lake City(COLUMN)97(COLUMN)61 San Antonio(COLUMN)93(COLUMN)77 San Diego(COLUMN)75(COLUMN)65 San Francisco(COLUMN)58(COLUMN)53 San Juan, P.P.(COLUMN)88(COLUMN)76 St. Ste. Marie(COLUMN)65(COLUMN)42 Seattle(COLUMN)69(COLUMN)56 Shrevveport(COLUMN)94(COLUMN)73 Sioux Falls(COLUMN)75(COLUMN)64 Spokane(COLUMN)77(COLUMN)49 Syracuse(COLUMN)83(COLUMN)52 Topeka(COLUMN)85(COLUMN)66 Tucson(COLUMN)103(COLUMN)82 Tulsa(COLUMN)90(COLUMN)71 Washington(COLUMN)91(COLUMN)75 Wichia(COLUMN)86(COLUMN)71(END TABLE) Temperatures Abroad Yesterday(TABLE) City(COLUMN)Weather(COLUMN)Time(COLUMN)Temp. Aberdeen(COLUMN)clear(COLUMN)1 p.m.(COLUMN)63 Amsterdam(COLUMN)clear(COLUMN)1 p.m.(COLUMN)73 Ankara(COLUMN)clear(COLUMN)3 p.m.(COLUMN)93 Athens(COLUMN)clear(COLUMN)2 p.m.(COLUMN)95 Auckland(COLUMN)clear(COLUMN)midnight(COLUMN)46 Berlin(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)66 Birmingham(COLUMN)pt clyd(COLUMN)1 p.m.(COLUMN)63 Brussels(COLUMN)pt. clyd(COLUMN)1 p.m.(COLUMN)73 Casablanca(COLUMN)cloudy(COLUMN)noon(COLUMN)70 Copenhagen(COLUMN)clear(COLUMN)1 p.m.(COLUMN)75 Duplin(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)61 Genevva(COLUMN)clear(COLUMN)1 p.m.(COLUMN)75 Hong Kong(COLUMN)clear(COLUMN)8 p.m.(COLUMN)84 Lisbon(COLUMN)cloudy(COLUMN)noon(COLUMN)70 London(COLUMN)clear(COLUMN)1 p.m.(COLUMN)70 Madrid(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)82 Malta(COLUMN)clear(COLUMN)1 p.m.(COLUMN)88 Manila(COLUMN)clear(COLUMN)8 p.m.(COLUMN)84 Moscow(COLUMN)pt. cldy(COLUMN)3 p.m.(COLUMN)70 New Delhi(COLUMN)cloudy(COLUMN)5 p.m.(COLUMN)82 Nice(COLUMN)clear(COLUMN)1 p.m.(COLUMN)75 Oslo(COLUMN)clear(COLUMN)1 p.m.(COLUMN)81 Paris(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)75 Peking(COLUMN)clear(COLUMN)8 p.m.(COLUMN)82 Rome(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)81 Saigon(COLUMN)cloudy(COLUMN)8 p.m.(COLUMN)63 Sofia(COLUMN)clear(COLUMN)2 p.m.(COLUMN)81 Stockholm(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)73 Sydney(COLUMN)pt. cldy(COLUMN)10 p.m.(COLUMN)57 Tel Aviv(COLUMN)clear(COLUMN)2 p.m.(COLUMN)88 Tokyo(COLUMN)cloudy(COLUMN)9 p.m.(COLUMN)79 Tunis(COLUMN)clear(COLUMN)1 p.m.(COLUMN)84 Vienna(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)72 Warsaw(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)70(END TABLE) Temperatures (Western Hemisphere)(TABLE) City(COLUMN)Weather(COLUMN)H.(COLUMN)L. Acapulco(COLUMN)cloudy(COLUMN)91(COLUMN)78 Barbados(COLUMN)fair(COLUMN)86(COLUMN)78 Bermuda(COLUMN)fair(COLUMN)85(COLUMN)79 Bogota(COLUMN)pt. cldy(COLUMN)64(COLUMN)44 Calgary(COLUMN)rain(COLUMN)70(COLUMN)48 Coliacan(COLUMN)clear(COLUMN)95(COLUMN)77 Edmonton(COLUMN)rain(COLUMN)72(COLUMN)54 Havana(COLUMN)fair(COLUMN)91(COLUMN)77 Kingston(COLUMN)pt. cldy(COLUMN)90(COLUMN)77 Montego Bay(COLUMN)fair(COLUMN)88(COLUMN)76 Mexico City(COLUMN)haze(COLUMN)72(COLUMN)55 Monterrey(COLUMN)fair(COLUMN)96(COLUMN)72Montreal clear(COLUMN)75(COLUMN)48 Nassau(COLUMN)pt. cldy(COLUMN)91(COLUMN)73 Ottawa(COLUMN)clear(COLUMN)73(COLUMN)52 Regina(COLUMN)cloudy(COLUMN)81(COLUMN)61 St. Kitts(COLUMN)clear(COLUMN)89(COLUMN)77 St. Thomas(COLUMN)fair(COLUMN)91(COLUMN)80 Toronto(COLUMN)pt. cldy(COLUMN)81(COLUMN)54 Vancouver(COLUMN)pt. cldy(COLUMN)68(COLUMN)52 Veracruz(COLUMN)cloudy(COLUMN)86(COLUMN)72(END TABLE)