Washington: Today - Rain this morning, partly cloudy this afternoon and evening, highs in low to mid 80s, lows to mid 60s. Chance of rain is 70 per cent this morning, 20 per cent this afternoon and 10 per cent tonight. Sunday - Mostly sunny, high in mid 80s.

Maryland and Virginia: Today - Partly cloudy with rain likely this morning, ending by afternoon except for lingering showers along the Virginia ocean shores. Highs should be in the mid 70s to mid 80s, lows in 60s.Sunday - Mostly sunny, highs in 80s.

Lower Potomac and Chesapake Bay: Today - Rain this morning with poor visibility followed by partly cloudy skies with good visibility this afternoon and evening. Winds should be southwesterly at about 15 knots through tonight.

Extended Area Outlook: For Monday through Wednesday - Fair skies Monday and Wednesday with chance of rain Tuesday. Highs should average in 80s, lows in 60s through period. Washington's normal temperature range for this time of year is from 79 to 60.

West Virginia: Today - Partly cloudy, highs mid 70s to mid 80s, lows mid 50s to mid 60s. Sunday - Partly cloudy, highs in upper 70s to upper 80s.

The National Weather Forecast for Today - Showers and thunderstorms are likely over the Applachians, the upper Great Lakes and from the Carolinas northward over the Atlantic Coast states into southern New England. There is a chance of scattered thunder-showers in northern New England, eastern Kansas and western Missouri. Showers are likely from the Pacific northwest over Montana and northern California. It will be cool over most of the northern and central plateau and the Rocky Mountain region, portions of the northern Pacific Coast, North Dakota and northern New England. Warm temperatures can be expected over Georgia, Florida and West Texas. Most of the remainder of the nation will be seasonably mild.

ALMANAC DATA FOR Sept. 17, 1977. Sun rises 6:51 a.m., sets 7:14 p.m.; moon rises 11:14 a.m., sets 10:06 p.m. Tides: High 11:31 a.m. and midnight, low 6:06 a.m. and 6:09 p.m. High and low tides at the following locations can be obtained by sutracting the hours indicated from the tides above. Annapolis 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).

Pollen count 64 Ragweed (note more than 7 or higher is considered undesirable).

The Council of Governments' Air Qualtiy Index for yesterday showed the high reading in the Washington area during the 2 to 3 p.m. period was 17 for the pollutant, photochemical oxidants. Index values between 0 and 24 indicate good 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 remain about the same.

The National Weather Service forecasts the Potomac River stage at Little Falls should remain near 2.6 feet today.

Washington data at 8 p.m. (EDT) yesterday: Highest temperatures since 8 a.m. yesterday, 73 degrees at 3:15 p.m. Lowest temperature since midnight, 64 degrees at 1:01 a.m. Excess of temperature since Sept. 1, 32 degrees. Excess of temperature since Jan. 1, 368 degrees. Record high temperature for today, 93 degrees in 1958. Record low temperature for today, 44 degrees in 1923. Relative humidity: Maximum 100 per cent at 4 p.m.; Minimum, 84 per cent at 1 p.m. 24 hour precipitation, .08 inches. Deficiency of precipitation since Sept. 1, 1.58 inches.Deficiency of precipitation since Jan. 1, 7.99 inches. Highest observed wind since 8 a.m. 8 miles per hour from the south at 12:50 Local Temp. Humidity(TABLE) Time(COLUMN)T.(COLUMN)H. 12 mi'nite(COLUMN)65(COLUMN)90 1 a.m.(COLUMN)64(COLUMN)92 2 a.m.(COLUMN)64(COLUMN)93 3 a.m.(COLUMN)64(COLUMN)92 4 a.m.(COLUMN)65(COLUMN)93 5 a.m.(COLUMN)65(COLUMN)93 6 a.m.(COLUMN)65(COLUMN)93 7 a.m.(COLUMN)65(COLUMN)96 8 a.m.(COLUMN)66(COLUMN)93 9 a.m.(COLUMN)66(COLUMN)93 10 a.m.(COLUMN)63(COLUMN)93 11 a.m.(COLUMN)69(COLUMN)90 12 noon(COLUMN)71(COLUMN)87 1 p.m.(COLUMN)73(COLUMN)84 2 p.m.(COLUMN)73(COLUMN)87 3 p.m.(COLUMN)72(COLUMN)93 4p.m.(COLUMN)72(COLUMN)103 5 p.m.(COLUMN)72(COLUMN)100 6 p.m.(COLUMN)72(COLUMN)100(END TABLE)(TABLE) City(COLUMN)H.(COLUMN)L. Albany(COLUMN)66(COLUMN)52 Alburquerque(COLUMN)84(COLUMN)56 Amarlin(COLUMN)90(COLUMN)65 Anchorage(COLUMN)53(COLUMN)49 Asheville(COLUMN)71(COLUMN)65 Atlanta(COLUMN)87(COLUMN)70 Atlantic City(COLUMN)69(COLUMN)65 Austin(COLUMN)93(COLUMN)71 Baltimore(COLUMN)67(COLUMN)62 Billings(COLUMN)68(COLUMN)47 Birmingham(COLUMN)86(COLUMN)71 Bismarck(COLUMN)83(COLUMN)55 Boise(COLUMN)76(COLUMN)49 Boston(COLUMN)62(COLUMN)58 Brownsville(COLUMN)92(COLUMN)70 Buffalo(COLUMN)68(COLUMN)55 Burlington, Vt.(COLUMN)64(COLUMN)50 Casper(COLUMN)78(COLUMN)43 Ch'leston, S.C.(COLUMN)89(COLUMN)79 Ch'lston, W. Va.(COLUMN)81(COLUMN)65 Charlotte, N.C.(COLUMN)75(COLUMN)70 Cheyenne(COLUMN)74(COLUMN)47 Chicago(COLUMN)66(COLUMN)63 Cincinnati(COLUMN)81(COLUMN)63 Cleveland(COLUMN)62(COLUMN)60 Columbia, S.C.(COLUMN)90(COLUMN)70 Columbus, Ohio(COLUMN)75(COLUMN)66 Dal. Ft. Worth(COLUMN)91(COLUMN)70 Dayton(COLUMN)78(COLUMN)67 Denver(COLUMN)82(COLUMN)51 Des Moines(COLUMN)66(COLUMN)59 Detroit(COLUMN)64(COLUMN)61 Duluth(COLUMN)70(COLUMN)45 El Paso(COLUMN)92(COLUMN)73 Fairbanks(COLUMN)50(COLUMN)45 Fargo(COLUMN)78(COLUMN)57 Flagstaff(COLUMN)72(COLUMN)53 Great Falls(COLUMN)73(COLUMN)46 Hartford(COLUMN)79(COLUMN)55 Helena(COLUMN)64(COLUMN)47 Honolulu(COLUMN)90(COLUMN)79 Houston(COLUMN)84(COLUMN)72 Indianapolis(COLUMN)81(COLUMN)69 Jackson, Miss(COLUMN)77(COLUMN)68 Jackonville(COLUMN)90(COLUMN)73 Juneau(COLUMN)61(COLUMN)40 Kansas City(COLUMN)61(COLUMN)58 Las Vegas(COLUMN)91(COLUMN)69 Little Rock(COLUMN)81(COLUMN)66 Los Angeles(COLUMN)74(COLUMN)61 Louisville(COLUMN)83(COLUMN)68 Memphis(COLUMN)85(COLUMN)71 Miami Beach(COLUMN)86(COLUMN)75 Midland(COLUMN)94(COLUMN)71 Milwaukee(COLUMN)60(COLUMN)57 Mpls. St. Paul(COLUMN)72(COLUMN)50 Nashville(COLUMN)86(COLUMN)70 New Orleans(COLUMN)76(COLUMN)71 New York(COLUMN)68(COLUMN)61 Norfolk(COLUMN)75(COLUMN)67 North Platte(COLUMN)77(COLUMN)56 Oklahoma City(COLUMN)83(COLUMN)67 Omaha(COLUMN)71(COLUMN)59 Orlando(COLUMN)92(COLUMN)77 Philadelphia(COLUMN)71(COLUMN)61 Phoenix(COLUMN)100(COLUMN)77 Pittsburgh(COLUMN)58(COLUMN)56 Portland, Me.(COLUMN)67(COLUMN)45 Portland, Ore.(COLUMN)66(COLUMN)54 Providence(COLUMN)67(COLUMN)55 Raleigh(COLUMN)79(COLUMN)68 Rapid City(COLUMN)85(COLUMN)49 Reno(COLUMN)76(COLUMN)43 Richmond(COLUMN)76(COLUMN)66 St. Louis(COLUMN)78(COLUMN)62 St. Ptd. Tampa(COLUMN)92(COLUMN)77 Salt Lake City(COLUMN)80(COLUMN)54 San Antonio(COLUMN)88(COLUMN)68 San Diego(COLUMN)75(COLUMN)68 San Francisco(COLUMN)62(COLUMN)56 San Juan, P.R.(COLUMN)86(COLUMN)75 St. Ste. Marie(COLUMN)66(COLUMN)52 Seattle(COLUMN)66(COLUMN)52 Shreveport(COLUMN)89(COLUMN)65 Sioux Falls(COLUMN)73(COLUMN)53 Spokane(COLUMN)66(COLUMN)47 Syracuse(COLUMN)70(COLUMN)58 Topeka(COLUMN)66(COLUMN)58 Tucson(COLUMN)90(COLUMN)71 Tulsa(COLUMN)76(COLUMN)65 Washington(COLUMN)66(COLUMN)63 Wichita(COLUMN)75(COLUMN)65(END TABLE)(TABLE) City(COLUMN)Weather(COLUMN)Time(COLUMN)Temp. Aberdeen(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)50 Amsterdam(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)57 Ankara(COLUMN)clear(COLUMN)3 p.m.(COLUMN)73 Athens(COLUMN)clear(COLUMN)2 p.m.(COLUMN)84 Auckland(COLUMN)drizzle(COLUMN)midnight(COLUMN)46 Berlin(COLUMN)clear(COLUMN)1 p.m.(COLUMN)54 Birmingham(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)55 Brussels(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)57 Cairo(COLUMN)clear(COLUMN)2 p.m.(COLUMN)88 Casablanca(COLUMN)pt. cldy(COLUMN)noon(COLUMN)77 Copenhagen(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)55 Dublin(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)55 Geneva(COLUMN)cloudy(COLUMN)3 p.m.(COLUMN)84 Lisbon(COLUMN)cloudy(COLUMN)noon(COLUMN)79 London(COLUMN)pt.cldy(COLUMN)1 p.m.(COLUMN)57 Madrid(COLUMN)clear(COLUMN)1 p.m.(COLUMN)81 Malta(COLUMN)clear(COLUMN)1 p.m.(COLUMN)81 Manila(COLUMN)pt. cldy(COLUMN)8 p.m.(COLUMN)81 Moscow(COLUMN)rain(COLUMN)3 p.m.(COLUMN)43 New Delhi(COLUMN)cloudy(COLUMN)5 p.m.(COLUMN)77 Nice(COLUMN)clear(COLUMN)1 p.m.(COLUMN)73 Oslo(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)55 Paris(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)59 Peking(COLUMN)rain(COLUMN)8 p.m.(COLUMN)63 Rome(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)77 Saigon(COLUMN)storm(COLUMN)8 p.m.(COLUMN)84 Sofla(COLUMN)clear(COLUMN)2 p.m.(COLUMN)73 Stockholm(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)46 Sydney(COLUMN)pt. cldy(COLUMN)10 p.m.(COLUMN)57 Tel Aviv(COLUMN)clear(COLUMN)2 P.m.(COLUMN)86 Tokyo(COLUMN)clear(COLUMN)9 p.m.(COLUMN)66 Tunis(COLUMN)clear(COLUMN)1 P.m.(COLUMN)82 Vienna(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)59 Warsaw(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)52(END TABLE) Temperatures (Western Hemisphere)(TABLE) City(COLUMN)Weather(COLUMN)H.(COLUMN)L. Acapulco(COLUMN)pt. cldy(COLUMN)90(COLUMN)77 Barbados(COLUMN)pt. cldy(COLUMN)88(COLUMN)80 Bermuda(COLUMN)cloudy(COLUMN)87(COLUMN)78 Calgary(COLUMN)cloudy(COLUMN)45(COLUMN)40 Edmonton(COLUMN)rain(COLUMN)50(COLUMN)43 Havana(COLUMN)pt. cldy(COLUMN)94(COLUMN)76 Kingston(COLUMN)pt. cldy(COLUMN)91(COLUMN)75 Montego Bay(COLUMN)pt. cldy(COLUMN)88(COLUMN)76 Mexico City(COLUMN)pt. cldy(COLUMN)74(COLUMN)58 Montreal(COLUMN)cloudy(COLUMN)63(COLUMN)50 Nassau(COLUMN)pt. cldy(COLUMN)90(COLUMN)77 Ottawa(COLUMN)rain(COLUMN)66(COLUMN)50 Regianb(COLUMN)rain(COLUMN)75(COLUMN)50 St. Kitts(COLUMN)pt. cldy(COLUMN)89(COLUMN)75 St. Thomas(COLUMN)pt. cldy(COLUMN)88(COLUMN)73 Toronto(COLUMN)rain(COLUMN)63(COLUMN)57 Vancouver(COLUMN)pt. cldy(COLUMN)59(COLUMN)52 Veracruz(COLUMN)cloudy(COLUMN)84(COLUMN)74 Winnipeg(COLUMN)pt. cldy(COLUMN)77(COLUMN)54(END TABLE)