Today -- Snow changing to rain, high in upper 30s, low in mid 20s. Chance of precipitation is near 100 percent today and 40 percent tonight. Wind will be from the northeast at from 10 to 20 mph. Saturday -- Partly cloudy, high near 40.

Maryland and Virginia: Today --Snow or rain, highs from the 30s to the 40s, lows from the teens to the mid 20s. Saturday -- Partly cloudy, highs from the 30s to the 40s.

Lower Potomac and Chesapeeke Bay: Today -- Snow or rain, visibility will be less than 3 miles. Wind will be from the east at up to 25 knots. Waves in unprotected waters will be from 2 to 4 feet.

Extended Area Forecast for Sunday through Tuesday: Fair during the beginning of the period, chance of rain or snow thereafter. Highs will be from the 30s to the 40s, lows from the 20s to the 30s. Normal Washington temperatures for the period are a high of 51 and a low of 32.

West Virginia: Today -- Snow, highs in the low 30s, lows in the teens. Saturday -- Partly cloudy highs from the 20s to the low 30s. The National Weather Forecast for today -- Snow will spread from the lower Ohio Valley to the northern Atlantic Coast. Rain and scattered thunderstorms will cover the eastern Gulf Coast and extend through the Carolinas into Virginia. Snow flurries are likely over the high Plains of eastern Colorado and northwestern Texas. Rain or snow will scatter over the Southwest, with locally heavy rains possible in Southern California. Skies will be mostly sunny from the upper Mississippi Valley through the northern Rockies into the Pacific Northwest. Temperatures will be very cold over the Plains and Mississippi Valley and cool elsewhere except for mild readings over Florida.

Almanac Data for today: Sun rises 6:30 a.m., sets 6:03 p.m. Moon rises 2:05 a.m., sets 12:25 p.m. Tides: high 2:03 a.m. and 2:38 p.m., low 9:03 a.m. and 9:52 p.m. High and low tides at the following locations may be obtained by subtracting the hours indicated from the hours 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 23 for the pollutant, photochemical oxidants. Index values between zero and 24 indicate good air quality. When t 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 be near 3.7 feet today.

Washington data at 7 p.m. (EST) yesterday: Highest temperature since 7 a.m. yesterday, 35 degrees at 3:30 p.m. Lowest temperature since midnight, 22 degrees at 5:40 a.m. Deficiency of temperature since Mar. 1, 17 degrees. Deficiency of temperature since Jan. 1, 264 degrees. Record high temperature for today, 79 degrees in 1923. Record low temperature for today, 11 degrees in 1925. Relative humidity: Maximum, 35 per cent at 2 a.m.; Minimum, 26 per cent at 1 p.m. Deficiency of precipitation since March 1, .12 inches. Excess of precipitation since Jan. 1, 2.31 Inches. Highest observed wind since 7 a.m. 14 miles per hour from the northwest at 9 a.m. Peak gust since 8 a.m., 22 miles per hour from the northwest at 9:02 a.m. Local Temp., Humidity (TABLE) Time(COLUMN)T.(COLUMN)H. 12 midnight(COLUMN)29(COLUMN)49 1 a.m.(COLUMN)27(COLUMN)55 2 a.m.(COLUMN)26(COLUMN)58 3 a.m.(COLUMN)25(COLUMN)53 4 a.m.(COLUMN)24(COLUMN)52 5 a.m.(COLUMN)23(COLUMN)55 6 a.m.(COLUMN)22(COLUMN)57 7 a.m.(COLUMN)22(COLUMN)55 8 a.m.(COLUMN)24(COLUMN)50 9 a.m.(COLUMN)27(COLUMN)46 10 a.m.(COLUMN)31(COLUMN)38 11 a.m.(COLUMN)32(COLUMN)36 12 noon(COLUMN)32(COLUMN)32 1 p.m.(COLUMN)34(COLUMN)26 2 p.m.(COLUMN)34(COLUMN)26 3 p.m.(COLUMN)34(COLUMN)28 4 p.m.(COLUMN)33(COLUMN)32 5 p.m.(COLUMN)33(COLUMN)32 6 p.m.(COLUMN)32(COLUMN)33 7 p.m.(COLUMN)32(COLUMN)33(END TABLE) Temperatures ending 7 a.m. (EST) yesterday: (TABLE) City(COLUMN)H.(COLUMN)L. Albany(COLUMN)30(COLUMN)4 Albuquerque(COLUMN)56(COLUMN)38 Amarillo(COLUMN)40(COLUMN)34 Anchorage(COLUMN)34(COLUMN)11 Asheville(COLUMN)43(COLUMN)26 Atlanta(COLUMN)53(COLUMN)32 Atlantic City(COLUMN)31(COLUMN)21 Austin(COLUMN)55(COLUMN)52 Baltimore(COLUMN)36(COLUMN)20 Billings(COLUMN)10(COLUMN)-10 Birmingham(COLUMN)47(COLUMN)36 Bismarck(COLUMN)41(COLUMN)8 Boise(COLUMN)49(COLUMN)20 Boston(COLUMN)32(COLUMN)16 Brownsville(COLUMN)78(COLUMN)68 Buffalo(COLUMN)27(COLUMN)-2 Burlington(COLUMN)15(COLUMN)-6 Casper(COLUMN)42(COLUMN)2 Charleston, SC(COLUMN)52(COLUMN)39 Chastn, W.Va.(COLUMN)34(COLUMN)9 Charlotte(COLUMN)53(COLUMN)28 Chevenne(COLUMN)37(COLUMN)6 Chicago(COLUMN)26(COLUMN)11 Cincinnati(COLUMN)29(COLUMN)9 Cleveland(COLUMN)25(COLUMN)-2 Columbia, S.C.(COLUMN)57(COLUMN)35 Columbus(COLUMN)27(COLUMN)1 Dal. Ft. Worth(COLUMN)48(COLUMN)43 Dayton(COLUMN)29(COLUMN)7 Denver(COLUMN)39(COLUMN)16 Des Moines(COLUMN)24(COLUMN)19 Detroit(COLUMN)28(COLUMN)-4 Duluth(COLUMN)22(COLUMN)-11 Fl Paso(COLUMN)68(COLUMN)52 Fairbanks(COLUMN)32(COLUMN)7 Fargo(COLUMN)13(COLUMN)2 Flagstaff(COLUMN)41(COLUMN)35 Great Falls(COLUMN)5(COLUMN)-14 Hartford(COLUMN)31(COLUMN)14 Helena(COLUMN)21(COLUMN) Houston(COLUMN)60(COLUMN)55 Indianapolis(COLUMN)30(COLUMN)17 Jackson, Miss.(COLUMN)52(COLUMN)42 Jacksonville(COLUMN)65(COLUMN)42 Juneau(COLUMN)37(COLUMN)11 Kansas City(COLUMN)28(COLUMN)26 Las Vegas(COLUMN)62(COLUMN)52 Little Rock(COLUMN)39(COLUMN)32 Los Angeles(COLUMN)62(COLUMN)57 Louisville(COLUMN)34(COLUMN)20 Memphis(COLUMN)42(COLUMN)37 Miami Beach(COLUMN)86(COLUMN)70 Midland-Odessa(COLUMN)63(COLUMN)41 Milwaukee(COLUMN)23(COLUMN)3 Mpls. St. Paul(COLUMN)23(COLUMN)16 Nashville(COLUMN)37(COLUMN)31 New Orleans(COLUMN)62(COLUMN)53 New York(COLUMN)32(COLUMN)19 Norfolk(COLUMN)34(COLUMN)27 North Platte(COLUMN)21(COLUMN)17 Oklahoma City(COLUMN)37(COLUMN)36 Omaha(COLUMN)24(COLUMN)20 Orlando(COLUMN)81(COLUMN)56 Philadelphia(COLUMN)33(COLUMN)17 Phoenix(COLUMN)69(COLUMN)58 Pittsburgh(COLUMN)29(COLUMN)5 Portland, Me.(COLUMN)30(COLUMN)-1 Portland, Ore.(COLUMN)51(COLUMN)41 Providence(COLUMN)29(COLUMN)11 Raleigh(COLUMN)44(COLUMN)24 Rapid City(COLUMN)17(COLUMN)7 Reno(COLUMN)52(COLUMN)41 Richmond(COLUMN)37(COLUMN)19 St. Louis(COLUMN)30(COLUMN)21 St. Prbg. Toa.(COLUMN)75(COLUMN)54 Salt Lake City(COLUMN)48(COLUMN)39 San Antonio(COLUMN)65(COLUMN)55 San Diego(COLUMN)67(COLUMN)62 San Francisco(COLUMN)62(COLUMN)55 San Juan(COLUMN)86(COLUMN)76 St. Sta. Maria(COLUMN)19(COLUMN)-7 Seattle(COLUMN)57(COLUMN)39 Shreveport(COLUMN)50(COLUMN)37 Sioux Falls(COLUMN)19(COLUMN)16 Spokane(COLUMN)33(COLUMN)23 Syracuse(COLUMN)31(COLUMN)1 Topeka(COLUMN)31(COLUMN)30 Tucson(COLUMN)62(COLUMN)55 Tulsa(COLUMN)39(COLUMN)35 Washington(COLUMN)39(COLUMN)22 Wichita(COLUMN)32(COLUMN)30(END TABLE) Temperatures Abroad Yesterday (TABLE) City(COLUMN)Weather(COLUMN)Time(COLUMN)Temp. Aberdeen(COLUMN)clear(COLUMN)1 p.m.(COLUMN)46 Amsterdam(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)50 Ankara(COLUMN)pt. cldy.(COLUMN)3 p.m.(COLUMN)57 Athens(COLUMN)cloudy(COLUMN)2 p.m.(COLUMN)63 Auckland(COLUMN)clear(COLUMN)mid.(COLUMN)66 Berlin(COLUMN)haze(COLUMN)1 p.m.(COLUMN)48 Birmingham(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)45 Brussels(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)48 Casablanca(COLUMN)cloudy(COLUMN)noon(COLUMN)64 Copenhagen(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)37 Dublin(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)48 Geneva(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)43 Hong Kong(COLUMN)cloudy(COLUMN)8 p.m.(COLUMN)66 Lisbon(COLUMN)cloudy(COLUMN)noon(COLUMN)61 London(COLUMN)rain(COLUMN)1 p.m.(COLUMN)46 Madrid(COLUMN)rain(COLUMN)1 p.m.(COLUMN)52 Malta(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)57 Manila(COLUMN)clear(COLUMN)8 p.m.(COLUMN)79 Moscow(COLUMN)cloudy(COLUMN)3 p.m.(COLUMN)36 New Delhi(COLUMN)clear(COLUMN)5 p.m.(COLUMN)77 Nice(COLUMN)rain(COLUMN)1 p.m.(COLUMN)55 Oslo(COLUMN)rain(COLUMN)1 p.m.(COLUMN)34 Paris(COLUMN)rain(COLUMN)1 p.m.(COLUMN)46 Peking(COLUMN)pt. cldy.(COLUMN)8 p.m.(COLUMN)36 Rome(COLUMN)clear(COLUMN)1 p.m.(COLUMN)59 Saigon(COLUMN)clear(COLUMN)8 p.m.(COLUMN)82 Sofia(COLUMN)pt. cldy.(COLUMN)2 p.m.(COLUMN)59 Stockholm(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)34 Sydney(COLUMN)clear(COLUMN)10 p.m.(COLUMN)75 Tel Aviv(COLUMN)clear(COLUMN)2 p.m.(COLUMN)82 Tokyo(COLUMN)clear(COLUMN)9 p.m.(COLUMN)45 Tunis(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)59 Vienna(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)48 Warsaw(COLUMN)clear(COLUMN)1 p.m.(COLUMN)48(END TABLE) Temperatures (Western Hemisphere) (TABLE) City(COLUMN)Weather(COLUMN)High(COLUMN)Low Acapulco(COLUMN)fair(COLUMN)86(COLUMN)73 Barbados(COLUMN)pt. cldy(COLUMN)84(COLUMN)77 Bermuda(COLUMN)pt. cldy(COLUMN)78(COLUMN)68 Calgary(COLUMN)snow(COLUMN)12(COLUMN)-18 Culiacan(COLUMN)clear(COLUMN)91(COLUMN)61 Edmonton(COLUMN)cloudy(COLUMN)10(COLUMN)-8 Havana(COLUMN)cloudy(COLUMN)79(COLUMN)61 Kingston(COLUMN)clear(COLUMN)86(COLUMN)73 Montego Bay(COLUMN)clear(COLUMN)82(COLUMN)72 Mexico City(COLUMN)clear(COLUMN)81(COLUMN)59 Monterrey(COLUMN)fair(COLUMN)84(COLUMN)63 Montreal(COLUMN)clear(COLUMN)19(COLUMN)-4 Nassau(COLUMN)fair(COLUMN)82(COLUMN)68 Ottawa(COLUMN)clear(COLUMN)19(COLUMN)1 Regina(COLUMN)snow(COLUMN)10(COLUMN)-17 St. Kitts(COLUMN)clear(COLUMN)87(COLUMN)72 St. Thomas(COLUMN)pt. cldy(COLUMN)79(COLUMN)71 Toronto(COLUMN)clear(COLUMN)21(COLUMN)3 Vancouver(COLUMN)clear(COLUMN)46(COLUMN)28 Veracruz(COLUMN)fair(COLUMN)81(COLUMN)66 Winnipeg(COLUMN)cloudy(COLUMN)7(COLUMN)-14(END TABLE)