Washington: Today, Sunny, high near 70, low in the low 40s. The chance of rain is near zero. Thursday - Partly cloudy, high near 70.

Maryland and Virginia: Today - Sunny, highs in the 60s, lows from the 30s to the low 40s. Thursday - Partly cloudy, highs in the 60s.

Lower Potomac and Chesapeake Bay: Today - Fair with visibility of more than 5 miles.Winds will be from the southeast at from 10 to 15 knots. Waves in unprotected waters will be less than 2 feet.

West Virginia: Today - Sunny, highs near 70, lows from the 30s to the mid 40s. Thursday - Sunny, highs from the upper 60s to the mid 70s.

Extended Area Forecast for Friday through Sunday: Cloudy with a chance of showers on the weekend. Highs will be from the 60s to to mid 70s, lows from the 40s to the 50s. Normal Washington temperatures for the period are a high of 53 and a low of 34.

THE NATIONAL WEATHER FORECAST for today - Showers with snow over the higher elevations will continue from the northern half of the Pacific Coast into the northern Rockies. Some cloudiness will also move across the western Great Lakes, but most other areas will have sunny skies. Temperatures will be warmer over the eastern third of the nation. It will be a little cooler, but still mild across most of the Rockies and Plains and also in the Mississippi Valley. The Pacific Coast will be cool.

Almanac data for today - Sun rises 6:20 a.m., sets 6:90 p.m.; moon rises 10:57 p.m., sets 8:48 a.m. Tides: High 10:37 a.m. and 11:04 p.m., low 4:53 a.m. and 5:33 p.m. High and low tides at the following points 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); Soloman's 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 25 for the pollutant, photochemical oxidants. Index values between 25 and 49 indicate fair 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 indicated the air quality will be fair.

The National Weather Service forecasts that the Potomac River stage at Little Falls will be near 1.4 feet.

Washington data at 7 p.m. (EST) yesterday: Highest temperature since 7 a.m. yesterday, 57 degrees at 3:19 p.m. Lowest temperature since midnight, 35 degrees at 6:15 a.m. Excess of temperature since March 1, 57 degrees. Deficiency of temperature since Jan. 1, 200 degrees. Record high temperature for today, 80 degrees in 1964. Records low temperature for today, 16 degrees in 1932. Relative humidity: Maximum, 64 per cent at 7 a.m.; minimum, 25 per cent at 5 p.m. Deficiency precipitation since March 1, .79 inches. Deficiency of precipitation since Jan. 1, 3.70 inches. Highest observed wind since 7 a.m. 14 miles per hour from the west-northwest at 10 a.m. Peak gust since 7 a.m., 25 miles per hour from the west at 2:21 p.m. Local Temp., Humidity(TABLE) Time(COLUMN)(COLUMN).(COLUMN)H. 12 mid.(COLUMN)41(COLUMN)51 1 a.m.(COLUMN)41(COLUMN)53 2 a.m.(COLUMN)42(COLUMN)51 3 a.m.(COLUMN)40(COLUMN)55 4 a.m.(COLUMN)40(COLUMN)55 5 a.m.(COLUMN)38(COLUMN)59 6 a.m.(COLUMN)36(COLUMN)64 7 a.m.(COLUMN)36(COLUMN)64 8(COLUMN)41(COLUMN)53 9 a.m.(COLUMN)44(COLUMN)47 10 a.m.(COLUMN)47(COLUMN)38 11 a.m.(COLUMN)49(COLUMN)41 12 noon(COLUMN)53(COLUMN)34 1 p.m.(COLUMN)53(COLUMN)34 2 p.m.(COLUMN)54(COLUMN)31 3(COLUMN)56(COLUMN)28 4 p.m.(COLUMN)57(COLUMN)26 5 p.m.(COLUMN)57(COLUMN)25 6 p.m.(COLUMN)54(COLUMN)26 7 p.m. 53(COLUMN)28(END TABLE) Temperatures ending 8 a.m. (EST) yesterday:(TABLE) City(COLUMN)H.(COLUMN)L. Albany(COLUMN)43(COLUMN)31 Albuquerque(COLUMN)64(COLUMN)35 Amarillo(COLUMN)72(COLUMN)40 Anchorage(COLUMN)23(COLUMN)7 Asheville(COLUMN)50(COLUMN)22 Atlanta(COLUMN)54(COLUMN)29 Atlantic City(COLUMN)44(COLUMN)28 Austin(COLUMN)70(COLUMN)41 Baltimore(COLUMN)54(COLUMN)30 Billings(COLUMN)63(COLUMN)42 Birmingham(COLUMN)59(COLUMN)32 Bismack(COLUMN)61(COLUMN)29 Boise(COLUMN)57(COLUMN)43 Boston(COLUMN)42(COLUMN)35 Brownsville(COLUMN)70(COLUMN)40 Buffalo(COLUMN)33(COLUMN)26 Burlington(COLUMN)36(COLUMN)26 Casper(COLUMN)53(COLUMN)36 Charleston, S.C.(COLUMN)62(COLUMN)44 Charleston, WVa.(COLUMN)44(COLUMN)23 Charlotte(COLUMN)57(COLUMN)30 Cheyenne(COLUMN)57(COLUMN)29 Chicago(COLUMN)47(COLUMN)35 Cincinnati(COLUMN)47(COLUMN)26 Cleveland(COLUMN)40(COLUMN)24 Columbia, S.C.(COLUMN)61(COLUMN)31 Columbus(COLUMN)38(COLUMN)22 Dal.-Ft. Worth(COLUMN)70(COLUMN)44 Dayton(COLUMN)40(COLUMN)26 Denver(COLUMN)64(COLUMN)32 Des Milnes(COLUMN)64(COLUMN)38 Detroit(COLUMN)45(COLUMN)29 Duluth(COLUMN)41(COLUMN)30 El Paso(COLUMN)65(COLUMN)24 Fairbancks(COLUMN)0(COLUMN)-20 Fargo(COLUMN)40(COLUMN)32 Flagstaff(COLUMN)61(COLUMN)30 Great Falls(COLUMN)57(COLUMN)45 Hartford(COLUMN)42(COLUMN)33 Helena(COLUMN)54(COLUMN)42 Honolulu(COLUMN)82(COLUMN)72 Houston(COLUMN)0(COLUMN)51 Indianapolis(COLUMN)49(COLUMN)29 Jackson, Miss.(COLUMN)63(COLUMN)32 Jacksonville(COLUMN)72(COLUMN)40 Juneau(COLUMN)40(COLUMN)36 Kansas City(COLUMN)67 46 Las Vegas(COLUMN)70(COLUMN)42 Little Rock(COLUMN)66(COLUMN)49 Los Angeles(COLUMN)78(COLUMN)54 Louisville(COLUMN)54(COLUMN)29 Memphis(COLUMN)66(COLUMN)47 Miami Beach(COLUMN)84(COLUMN)67 Midland-Odessa(COLUMN)71(COLUMN)38 Mpls.-St. Paul(COLUMN)41(COLUMN)26 Nashville(COLUMN)58(COLUMN)32 New Orleans(COLUMN)64(COLUMN)35 New York(COLUMN)45(COLUMN)33 Norfolk(COLUMN)48(COLUMN)38 North Platte(COLUMN)65(COLUMN)25 Oklahoma City(COLUMN)72(COLUMN)44 Omaha(COLUMN)69(COLUMN)36 Orlando(COLUMN)76(COLUMN)51 Philadelphia(COLUMN)51(COLUMN)30 Phoenix(COLUMN)80(COLUMN)61 Pittsburgh(COLUMN)35(COLUMN)23 Portland, Maine(COLUMN)37(COLUMN)27 Portland, Ore(COLUMN)53(COLUMN)44 Providence(COLUMN)42(COLUMN)33 Raleigh(COLUMN)54(COLUMN)25 Rapid City(COLUMN)63(COLUMN)40 Reno(COLUMN)63(COLUMN)43 Richmond(COLUMN)57(COLUMN)26 St. Louis(COLUMN)61(COLUMN)42 St. Prbg.-Tampa(COLUMN)71(COLUMN)50 Salt Lake City(COLUMN)59(COLUMN)45 San Antonio(COLUMN)71(COLUMN)37 San Diego(COLUMN)73(COLUMN)59 San Francisco(COLUMN)61(COLUMN)51 San Juan(COLUMN)84(COLUMN)71 St. Ste. Marie(COLUMN)36(COLUMN)15 Seattle(COLUMN)55(COLUMN)43 Shreveport(COLUMN)72(COLUMN)37 Sioux Falls(COLUMN)40(COLUMN)18 Spokane(COLUMN)45(COLUMN)36 Syracuse(COLUMN)41(COLUMN)27 Tucson(COLUMN)79(COLUMN)52 Tulsa(COLUMN)74(COLUMN)44 Washington(COLUMN)55(COLUMN)35 Wichita(COLUMN)73(COLUMN)36(END TABLE)