Washington: Today - Partly cloudy, warmer. High between 50 and 65, low 35 to 40. Chance of precipitation is 10 per cent today, 40 per cent tonight. Wednesday - High 50 to 55.

Maryland and Virginia: Today - Partly cloudy, warmer. High in the mid 40s to mid 50s, low in the 30s. Wednesday - High in the 50s.

Lower Potomac and Chesapeake Bay: Today - Fair with southerly winds 10 to 20 knots. Waves 2 to 3 feet.

Extended Area Forecast for Thursday through Saturday: Chance of rain Thursday then partial clearing. Mild with highs in the 50s and lows in the 30s. Normal Washington temperatures for this period are a high of 44 and a low of 29.

West Virginia: Today - Mostly cloudy with a chance of rain in the north. High in the mid 40s to mid 50s, low in the upper 30s to mid 40s. Wednesday - Rain likely, high in the upper 40s to mid 50s.

The National Weather Forecast for today: Rain will extend from the northern half of the Pacific coast into the northern Rockies. Snow and snow flurries will range from the Great Lakes into New England, with rain over the eastern Mississippi valley and the Ohio valley. Temperatures will be cold or cool over portons of the central and southern Pacific coast, over Michigan and New England, and along the East coast. Most of the remainder of the country will be mild.

Almanac Data for today - Sun rises 7:18 a.m., sets 4:47 p.m.; moon rises 9:44 a.m., sets 8:32 p.m. Tides: high 9:52 a.m. and 10:17 p.m., low 4:19 a.m. and 4:34 p.m. High and low tides at the following locations may be obtained by subtracting the hours indicated from the tides above Annapolis (1 1/2), Bloody Point Lighthouse (4 1/2), Deale, Md. (4 1/2), 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 p.m. to 3 p.m. period was 15 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 be good.

The National Weather Service forecasts the Potomac River stage at Little Falls should fall slowly to 3.8 feet today. Local Temp., Humidity(TABLE) Time(COLUMN)T.(COLUMN)H. 12 midn.(COLUMN)23(COLUMN)50 1 a.m.(COLUMN)23(COLUMN)48 2 a.m.(COLUMN)21(COLUMN)52 3 a.m.(COLUMN)21(COLUMN)54 4 a.m.(COLUMN)19(COLUMN)65 5 a.m.(COLUMN)19(COLUMN)68 6 a.m.(COLUMN)20(COLUMN)62 7 a.m.(COLUMN)22(COLUMN)52 8 a.m.(COLUMN)22(COLUMN)55 9 a.m.(COLUMN)25(COLUMN)50 10 a.m.(COLUMN)29(COLUMN)45 11 a.m.(COLUMN)32(COLUMN)43 12 noon(COLUMN)34(COLUMN)42 1 p.m.(COLUMN)36(COLUMN)37 2 p.m.(COLUMN)38(COLUMN)34 3 p.m.(COLUMN)38(COLUMN)33 4 p.m.(COLUMN)40(COLUMN)31 5 p.m.(COLUMN)38(COLUMN)34 6 p.m.(COLUMN)38(COLUMN)42 7 p.m.(COLUMN)38(COLUMN)46(END TABLE) Temperatures ending 8 a.m. (EST) yesterday:(TABLE) City(COLUMN)H.(COLUMN)L. Albany(COLUMN)11(COLUMN)06 Albuquerque(COLUMN)61(COLUMN)28 Amarillo(COLUMN)63(COLUMN)34 Anchorage(COLUMN)10(COLUMN)06 Asheville(COLUMN)41(COLUMN)19 Atlanta(COLUMN)48(COLUMN)25 Atlantic City(COLUMN)25(COLUMN)16 Austin(COLUMN)54(COLUMN)49 Baltimore(COLUMN)29(COLUMN)11 Billings(COLUMN)48(COLUMN)40 Birmingham(COLUMN)49(COLUMN)30 Bismarck(COLUMN)20(COLUMN)10 Boise(COLUMN)49(COLUMN)35 Boston(COLUMN)17(COLUMN)05 Brownsville(COLUMN)61(COLUMN)52 Buffalo(COLUMN)18(COLUMN)04 Burlington, Vt.(COLUMN)05(COLUMN)13 Casper(COLUMN)47(COLUMN)39 Charleston, S.C.(COLUMN)46(COLUMN)33 Charleston, W.V.(COLUMN)24(COLUMN)13 Charlotte, N.C.(COLUMN)43(COLUMN)23 Cheyenne(COLUMN)54(COLUMN)29 Chicago(COLUMN)23(COLUMN)13 Cincinnati(COLUMN)16(COLUMN)09 Cleveland(COLUMN)12(COLUMN)06 Columbia, S.C.(COLUMN)47(COLUMN)19 Columbus, Ohio(COLUMN)14(COLUMN)08 Dal.-Ft. Worth(COLUMN)49(COLUMN)40 Dayton(COLUMN)16(COLUMN)03 Denver(COLUMN)67(COLUMN)33 Des Moines(COLUMN)36(COLUMN)21 Detroit(COLUMN)15(COLUMN)03 Duluth(COLUMN)11(COLUMN)07 El Paso(COLUMN)65(COLUMN)35 Fairbanks(COLUMN)30(COLUMN)46 Fargo(COLUMN)17(COLUMN)16 Flagstaff(COLUMN)59(COLUMN)27 Great Falls(COLUMN)52(COLUMN)37 Hartford(COLUMN)13(COLUMN)00 Helena(COLUMN)53(COLUMN)36 Honolulu(COLUMN)85(COLUMN)71 Houston(COLUMN)55(COLUMN)50 Indianapolis(COLUMN)16(COLUMN)16 Jackson, Miss.(COLUMN)52(COLUMN)30 Jacksonville(COLUMN)56(COLUMN)41 Juneau(COLUMN)15(COLUMN)11 Kansas City(COLUMN)40(COLUMN)36 Las Vegas(COLUMN)66(COLUMN)44 Little Rock(COLUMN)39(COLUMN)35 Los Angeles(COLUMN)63(COLUMN)57 Louisville(COLUMN)30(COLUMN)22 Memphis(COLUMN)48(COLUMN)43 Miami Beach(COLUMN)74(COLUMN)72 Midland-Odessa(COLUMN)65(COLUMN)45 Milwaukee(COLUMN)18(COLUMN)15 Mpls.-St. Paul(COLUMN)16(COLUMN)12 Nashville(COLUMN)38(COLUMN)21 New Orleans(COLUMN)54(COLUMN)44 New York(COLUMN)24(COLUMN)17 Norfolk(COLUMN)32(COLUMN)20 North Platte(COLUMN)54(COLUMN)17 Oklahoma City(COLUMN)46(COLUMN)42 Omaha(COLUMN)37(COLUMN)31 Orlando(COLUMN)73(COLUMN)54 Philadelphia(COLUMN)24(COLUMN)09 Phoenix(COLUMN)81(COLUMN)47 Pittsburgh(COLUMN)17(COLUMN)06 Portland, Maine(COLUMN)12(COLUMN)15 Portland, Ore.(COLUMN)55(COLUMN)48 Providence(COLUMN)16(COLUMN)04 Raleigh(COLUMN)37(COLUMN)13 Rapid City(COLUMN)49(COLUMN)30 Rena(COLUMN)59(COLUMN)31 Richmond(COLUMN)31(COLUMN)13 St. Louis(COLUMN)34(COLUMN)34 St.-Prbg-Tampa(COLUMN)69(COLUMN)50 Salt Lake City(COLUMN)55(COLUMN)37 San Antonio(COLUMN)51(COLUMN)50 San Diego(COLUMN)66(COLUMN)62 San Francisco(COLUMN)59(COLUMN)53 San Juan, P.R.(COLUMN)85(COLUMN)74 St. Ste. Marie(COLUMN)13(COLUMN)07 Seattle(COLUMN)51(COLUMN)47 Shreveport(COLUMN)48(COLUMN)41 Sioux Falls(COLUMN)33(COLUMN)17 Spokane(COLUMN)44(COLUMN)38 Syracuse(COLUMN)13(COLUMN)04 Topeka(COLUMN)45(COLUMN)35 Tucson(COLUMN)78(COLUMN)51 Tulsa(COLUMN)45(COLUMN)44 Washington(COLUMN)31(COLUMN)18 Wichita(COLUMN)42(COLUMN)38(END TABLE) Temperatures (Western Hemisphere)(TABLE) City(COLUMN)(COLUMN)H.(COLUMN)L. Acapulco(COLUMN)fair(COLUMN)90(COLUMN)75 Barbados(COLUMN)pt.cldy(COLUMN)84(COLUMN)77 Bermuda(COLUMN)pt.cldy(COLUMN)64(COLUMN)57 Bogota(COLUMN)cloudy(COLUMN)66(COLUMN)43 Havana(COLUMN)pt.cldy(COLUMN)77(COLUMN)72 Kingston(COLUMN)fair(COLUMN)90(COLUMN)73 Montego-Bay(COLUMN)pt.cldy(COLUMN)84(COLUMN)72 Mexico City(COLUMN)pt.cldy(COLUMN)68(COLUMN)48 Monterrey(COLUMN)pt.cldy(COLUMN)84(COLUMN)72 Nassau(COLUMN)pt.cldy(COLUMN)85(COLUMN)70 St. Kitts(COLUMN)cloudy(COLUMN)82(COLUMN)73 St. Thomas(COLUMN)pt.cldy(COLUMN)86(COLUMN)74 Veracruz(COLUMN)rain(COLUMN)75(COLUMN)64(END TABLE)