Washington: Today - Partly cloudy and cool high in the upper 60s, low in the low to mid 40s. The chance of rain is 10 per cent. Friday - Partly cloudy, high in the mid 60s.

Maryland and Virginia: Today - Partly cloudy and cool, highs will range from the upper 50s to near 73, lows in the 40s. Friday - Partly cloudy, high in the 60s.

Extended Area Outlook for Saturday through Monday: Fair and cool through the period with a chance of showers on Monday. Highs will range from the mid 40s to mid 50s. Normal Washington temperatures for the period are a high of 73 and low of 52.

Lower Potomac and Chesapeake Bay - Partly cloudy, with winds shifting to the northwest at 12 to 20 knots. Waves will average 2 feet or less. Visibility will be 3 to 5 miles.

West Virginia: Today - Partly cloudy, highs will range from the upper 50s to low 60s, lows will be in the 30s. Friday - Sunny and cool, high near 60.

The National Weather Forecast for today - Showers are likely for the lower Great Lakes and northern New England. Showers are indicated for southern and western Texas into the southern Plateau and southern California north across southern Nevada and southern Utah. A few showers are also predicted to-parts of the central Plains and from the northern Pacific California into the northern Rockies. Elsewhere partly sunny weather is expected. Mild temperatures are anticipated for the far southwest and in the Gulf Coast states into the mid Atlantic coastal area. It will be turning cooler through much of the northeast and warmer in the southern Plains.

Almanac data for Oct., 1977 - Sun rises 7:08 a.m., sets 6:44 p.m.; Moon rises - sets 2:57 p.m. Tides: High 2:50 a.m. and 3:24 p.m., low 10:10 a.m. and 10:24 p.m. High and low tides at the following locations can be obtained by subtracting the hours indicated from the tides above. Annapolis (1 1/2); Bloody Point Lighthouse (4 1/2); Deale, Md. (4 1/3); Colonial Beach (6); Norfolk (1 1/2); Virginia Beach (1); Solomons Island (6 1/2); Point Lookout (7).

Pollen Court 12 ragweed (note: More than 7 is considered undesirable.

The Council of Governments' Air Quality Index for yesterday showed the high reading in the Washington area during the 3 p.m. period was 25 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 sets 2:57 indicates that the air quality will improve.

The National Weather Service forecasts the Potamac River stage at Little Falls should fall to 2.7 feet today. Local Temp., Humidity(TABLE) Time(COLUMN)T.(COLUMN)H. 12 midn.(COLUMN)59(COLUMN)46 1 a.m.(COLUMN)55(COLUMN)63 2 a.m.(COLUMN)54(COLUMN)51 3 a.m.(COLUMN)56(COLUMN)57 4 a.m.(COLUMN)56(COLUMN)54 5 a.m.(COLUMN)52(COLUMN)59 6 a.m.(COLUMN)50(COLUMN)54 7 a.m.(COLUMN)52(COLUMN)61 8 a.m.(COLUMN)54(COLUMN)57 9 a.m.(COLUMN)57(COLUMN)51 10 a.m.(COLUMN)61(COLUMN)52 11 a.m.(COLUMN)65(COLUMN)42 12 noon(COLUMN)66(COLUMN)39 1 p.m.(COLUMN)68(COLUMN)33 2 p.m.(COLUMN)72(COLUMN)28 3 p.m.(COLUMN)73(COLUMN)26 4 p.m.(COLUMN)72(COLUMN)28 5 p.m.(COLUMN)72(COLUMN)33 6 p.m.(COLUMN)71(COLUMN)31 7 p.m.(COLUMN)68(COLUMN)35(END TABLE) Temperatures ending 8 a.m. (EDT) yesterday:(TABLE) City(COLUMN)H.(COLUMN)L. Albany(COLUMN)64(COLUMN)50 Albuquerque(COLUMN)78(COLUMN)58 Amarillo(COLUMN)76(COLUMN)60 Anchorage(COLUMN)52(COLUMN)37 Asheville(COLUMN)69(COLUMN)37 Atlanta(COLUMN)70(COLUMN)48 Atlantic City(COLUMN)67(COLUMN)50 Austin(COLUMN)82(COLUMN)61 Baltimore(COLUMN)72(COLUMN)44 Billings(COLUMN)50(COLUMN)38 Birmingham(COLUMN)70(COLUMN)48 Bismarck(COLUMN)56(COLUMN)36 Boise(COLUMN)64(COLUMN)42 Boston(COLUMN)63(COLUMN)51 Brownsville(COLUMN)87(COLUMN)68 Buffalo(COLUMN)63(COLUMN)51 Burlington Vt.(COLUMN)60(COLUMN)37 Casper(COLUMN)57(COLUMN)39 Charleston S. C.(COLUMN)70(COLUMN)45 Chareine W. Va.(COLUMN)64(COLUMN)39 Charlotte(COLUMN)67(COLUMN)45 Cheyenne(COLUMN)57(COLUMN)36 Chicago(COLUMN)70(COLUMN)56 Cincinnati(COLUMN)66(COLUMN)46 Cleveland(COLUMN)64(COLUMN)44 Columbus(COLUMN)65(COLUMN)44 Dal. Ft.-Worth(COLUMN)75(COLUMN)64 Dayton(COLUMN)67(COLUMN)49 Denver(COLUMN)67(COLUMN)38 Des Moines(COLUMN)68(COLUMN)51 Detroit(COLUMN)65(COLUMN)40 Duluth(COLUMN)55(COLUMN)35 El Paso(COLUMN)68(COLUMN)63 Fairbanks(COLUMN)35(COLUMN)29 Fargo(COLUMN)55(COLUMN)35 Flagstaff(COLUMN)78(COLUMN)42 Great Falls(COLUMN)43(COLUMN)29 Hartford(COLUMN)64(COLUMN)42 Helena(COLUMN)50(COLUMN)30 Honolulu(COLUMN)58(COLUMN)77 Houston(COLUMN)77(COLUMN)62 Indianapolis(COLUMN)69(COLUMN)51 Jackson(COLUMN)72(COLUMN)45 Jacksonville(COLUMN)74(COLUMN)51 Juneau(COLUMN)48(COLUMN)35 Kansas City(COLUMN)66(COLUMN)45 Las Vegas(COLUMN)96(COLUMN)65 Little Rock(COLUMN)73(COLUMN)59 Los Angeles(COLUMN)82(COLUMN)61 Louisville(COLUMN)68(COLUMN)49 Memphis(COLUMN)74(COLUMN)57 Miami Beach(COLUMN)82(COLUMN)28 Midland(COLUMN)73(COLUMN)65 Milwaukee(COLUMN)65(COLUMN)52 Mpls.-St. Paul(COLUMN)65(COLUMN)33 Nashville(COLUMN)70(COLUMN)44 New Orleans(COLUMN)75(COLUMN)54 New York(COLUMN)63(COLUMN)47 Norfolk(COLUMN)70(COLUMN)48 North Platte(COLUMN)60(COLUMN)42 Oklahoma City(COLUMN)59(COLUMN)56 Omaha(COLUMN)62(COLUMN)45 Orlando(COLUMN)83(COLUMN)61 Philadelphia(COLUMN)67(COLUMN)45 Phoenix(COLUMN)97(COLUMN)75 Pittsburgh(COLUMN)61(COLUMN)42 Portland Me.(COLUMN)58(COLUMN)33 Providence(COLUMN)62(COLUMN)33 Portland Or.(COLUMN)66(COLUMN)45 Providence(COLUMN)62(COLUMN)46 Raleigh(COLUMN)67(COLUMN)38 Rapid City(COLUMN)52(COLUMN)35 Reno(COLUMN)79(COLUMN)31 Richmond(COLUMN)68(COLUMN)38 St. Louis(COLUMN)69(COLUMN)55 St. Prbg.-Tampa(COLUMN)83(COLUMN)62 Salt Lake City(COLUMN)72(COLUMN)47 San Antonio(COLUMN)81(COLUMN)61 San Diego(COLUMN)79(COLUMN)67 San Francisco(COLUMN)62(COLUMN)54 San Juan(COLUMN)89(COLUMN)77 St. Ste Marie(COLUMN)64(COLUMN)45 Seattle(COLUMN)63(COLUMN)45 Shreveport(COLUMN)76(COLUMN)58 Sioux Falls(COLUMN)64(COLUMN)36 Spokane(COLUMN)55(COLUMN)39 Syracuse(COLUMN)64(COLUMN)46 Topeka(COLUMN)76(COLUMN)60 Tucson(COLUMN)90(COLUMN)72 Tulsa(COLUMN)71(COLUMN)59 Washington(COLUMN)73(COLUMN)50 Wichita(COLUMN)75(COLUMN)58(END TABLE) Temperatures (Western Hemisphere)(TABLE) City(COLUMN)Weather(COLUMN)H.(COLUMN)L. Acapulco(COLUMN)clear(COLUMN)90(COLUMN)77 Barbados(COLUMN)cloudy(COLUMN)84(COLUMN)78 Bermuda(COLUMN)cloudy(COLUMN)78(COLUMN)69 Bogota(COLUMN)clear(COLUMN)66(COLUMN)46 Calgary(COLUMN)clear(COLUMN)45(COLUMN)23 Culiacan(COLUMN)cloudy(COLUMN)95(COLUMN)77 Edmonton(COLUMN)clear(COLUMN)41(COLUMN)21 Havana(COLUMN)pt. cldy.(COLUMN)86(COLUMN)75 Kingston(COLUMN)clear(COLUMN)90(COLUMN)78 Montego Bay(COLUMN)clear(COLUMN)88(COLUMN)75 Mexico City(COLUMN)haze(COLUMN)73(COLUMN)59 Monterry(COLUMN)cloudy(COLUMN)73(COLUMN)69 Montreal(COLUMN)pt. cldy.(COLUMN)59(COLUMN)39 Nassau(COLUMN)pt. cldy.(COLUMN)82(COLUMN)75 Ottawa(COLUMN)pt. cldy.(COLUMN)59(COLUMN)41 Regina(COLUMN)snow(COLUMN)46(COLUMN)32 St. Kitts(COLUMN)pt. cldy.(COLUMN)88(COLUMN)78 St. Thomas(COLUMN)cloudy(COLUMN)89(COLUMN)78 Toronto(COLUMN)pt. cldy.(COLUMN)64(COLUMN)43 Vancouver(COLUMN)clear(COLUMN)55(COLUMN)41 Veracruz(COLUMN)clear(COLUMN)88(COLUMN)72 Winnipeg(COLUMN)snow(COLUMN)54(COLUMN)36(END TABLE)