Washington Today -- Mostly sunny, high in 40s, low in low to mid 30s. Chance of paecipitation near zero today, 10 per cent tonight. Wednesday -- Partly cloudy, high in 50s.

Maryland: Today -- Partly cloudy, high in low to mid 40s, low in upper 20s and 30s. Wednesday --Partly cloudy, high in low 50s.

Virginia: Today -- Mostly sunny, high in 40s to low 50s, low in 30s. Wednesday -- Mostly sunny, high in 50s to low 60s.

Lower Potomac and Chesapeake Bay: Today -- Fair skies with visibility greater than 5 miles through tonight. Winds should be southwesterly at 10 to 20 knots today and westerly at less than 10 knots tonight.

Extended Area Outlook: For Thursday through Saturday -- Chance of rain Wednesday followed by partly cloudy skies through remainder of period. Highs should average in 40s, lows near 30. Washington's normal temperature range for this time of year is from 48 to 30.

West Virginia: Today -- Partly cloudy, high in mid 40s to mid 50s, low in 30s. Wednesday -- Partly cloudy, high in mid 50s to mid 60s.

The Nation Yesterday: The first significant heavy snowfall of this year was expected over the California Sierras and the northern mountains last night.A cold front triggering the needed snowfall also bought scattered showers to much of the Pacific coast state, into Idaho and Nevada. Travel advisories were in effect for the Sierras and also for the northern California mountains for occasional heavy snow. A major storm center off the Washington coast brought 20 foot swells and gusty winds to the Pacific northwest Coast. Gusts to 98 m.p.h. were clocked at Pachena Point, on Vancouver Island just across from Tatoosh Island.Storm warnings were posted on the Washington coast with cale warnings on the Oregon shores. Unseasonably warm weather continued in extreme southeast California and southwest Arizona. Blythe, Calif. had a high of 93 degrees. Highs of 88 at Yuma, 85 at Phoenix and 76 at Winslow, all in Arizona, set new daily high records for yesterday's date. Phoenix has set or tied three high records in the past week. Seventy degree temperatures reached northward into central Nebraska and the low 80s touched central Kansas. Cities that set new daily high records included Topeka, Fort Hays, Dodge City and Concordia in Kansas, Norfolk and Omaha in Nebraska and Council Bluffs and Fort Dodge in Iowa. Warm temperatures extended into the central Rockles and the mid and lower Mississippi Valley.

The National Weather Forecast for Today -- Scattered snow flurries will fall from the mountains of northern New England across western New York into extreme northeast Ohio. Occasional rain showers, with snow over the mountains, will reach from the Pacific northwest across Montana into southern California and west portions of Wyoming, Colorado and Arizona. The rest of the nation will have sunny skies. It will be unseasonably warm over the central Plains and mild elsewhere over the Rockies and eastward through the lower Ohio Valley and the south and central Appalachians. The rest of the country will be seasonably cool.

Almanac data for Tues., Feb. 22, 1977: Sun rises 6:51 a.m., sets 5:53 p.m., moon rises 9:01 a.m., sets 10:35 p.m. Tides: High 10:55 a.m. and 11:14 p.m., low 5:22 a.m. and 5:51 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); Solomons Island (6 1/2); Point Lookout (73.

The National Weather Service forecasts that the Potomac River stage at Little Falls will remain near 3.5 feet today.

Washington data at 7 p.m. (EST) yesterday: Highest temperature since 7 a.m. yesterday, 39 degrees at 3:45 p.m. Lowest temperature since midnight, 27 degrees at 5:30 a.m. Deficiency of temperature since Feb. 1, 46 degrees. Deficiency or temperature since Jan. 1, 350 degrees. Record high temperature for today, 77 degrees in 1879. Record low temperature for today, 9 degrees in 1963. Relative humidity: Maximum, 55 per cent at 4 a.m.; Minimum, 30 per cent at 4 p.m. 24 hour precipitation, none. Deficiency of precipitation since Feb. 1, 1.75 inches. Deficiency of precipitation since Jan. 1, 2.87 inches. Highest observed wind since 7 a.m. 20 miles per hour from the N.W. at 11 a.m. Peak gust since 7 a.m., 23 miles per hour from the N.W. at 10 a.m. (TABLE) *3*Local Temp., Humidity Time(COLUMN)T.(COLUMN)H. 12 mid.(COLUMN)32(COLUMN)51 1 a.m.(COLUMN)32(COLUMN)51 2 a.m.(COLUMN)31(COLUMN)51 3 a.m.(COLUMN)29(COLUMN)53 4 a.m.(COLUMN)28(COLUMN)55 5 a.m.(COLUMN)28(COLUMN)55 6 a.m.(COLUMN)27(COLUMN)55 7 a.m.(COLUMN)27(COLUMN)55 8 a.m.(COLUMN)29(COLUMN)51 9 a.m.(COLUMN)30(COLUMN)47 10 a.m.(COLUMN)32(COLUMN)43 11 a.m.(COLUMN)34(COLUMN)38 12 noon(COLUMN)35(COLUMN)35 1 p.m.(COLUMN)37(COLUMN)34 2 p.m.(COLUMN)37(COLUMN)34 3 p.m.(COLUMN)38(COLUMN)33 4 p.m.(COLUMN)39(COLUMN)30 5 p.m.(COLUMN)38(COLUMN)31 6 p.m.(COLUMN)35(COLUMN)35 7 p.m.(COLUMN)35(COLUMN)37 8 p.m.(COLUMN)33(COLUMN)40 9 p.m.(COLUMN)32(COLUMN)43 10 p.m.(COLUMN)31(COLUMN)45 11 p.m.(COLUMN)30(COLUMN)47(END TABLE) (TABLE) *3*Temperatures ending 7 p.m. (EST) yesterday: City(COLUMN)L.(COLUMN)H. Albany(COLUMN)17(COLUMN)26 Albuquerque(COLUMN)23(COLUMN)67 Amarillo(COLUMN)32(COLUMN)76 Anchorage(COLUMN)34(COLUMN)43 Asheville(COLUMN)23(COLUMN)42 Atlanta(COLUMN)20(COLUMN)50 Atlantic City(COLUMN)27(COLUMN)34 Austin(COLUMN)43(COLUMN)73 Baltimore(COLUMN)25(COLUMN)36 Billings(COLUMN)39(COLUMN)64 Birmingham(COLUMN)21(COLUMN)58 Bismarck(COLUMN)24(COLUMN)50 Boise(COLUMN)33(COLUMN)50 Boston(COLUMN)30(COLUMN)32 Brownsville(COLUMN)61(COLUMN)76 Buffalo(COLUMN)10(COLUMN)20 Burlington, Vt.(COLUMN)17(COLUMN)24 Casper(COLUMN)36(COLUMN)58 Charleston, S.C.(COLUMN)33(COLUMN)50 Charleston, W.V.(COLUMN)20(COLUMN)28 Charlotte, N.C.(COLUMN)21(COLUMN)46 Cheyenne(COLUMN)34(COLUMN)60 Chicago(COLUMN)10(COLUMN)34 Cincinnati(COLUMN)14(COLUMN)31 Cleveland(COLUMN)9(COLUMN)24 Columbia, S.C.(COLUMN)19(COLUMN)52 Columbus, Ohio(COLUMN)13(COLUMN)27 Dal. Ft. Worth(COLUMN)38(COLUMN)72 Dayton(COLUMN)6(COLUMN)28 Denver(COLUMN)33(COLUMN)69 Des Moines(COLUMN)14(COLUMN)59 Detroit(COLUMN)7(COLUMN)28 Duluth(COLUMN)8(COLUMN)35 El Paso(COLUMN)24(COLUMN)75 Fargo(COLUMN)19(COLUMN)43 Flagstaff(COLUMN)28(COLUMN)60 Great Falls(COLUMN)40(COLUMN)59 Hartford(COLUMN)23(COLUMN)32 Helena(COLUMN)27(COLUMN)53 Honolulu(COLUMN)68(COLUMN)86 Houston(COLUMN)52(COLUMN)72 Indianapolis(COLUMN)19(COLUMN)33 Jackson, Miss.(COLUMN)29(COLUMN)70 Jacksonville(COLUMN)32(COLUMN)57 Juneau(COLUMN)43(COLUMN)48 Kansas City(COLUMN)29(COLUMN)68 LAS Vegas(COLUMN)47(COLUMN)80 Little Rock(COLUMN)31(COLUMN)70 Los Angeles(COLUMN)54(COLUMN)70 Louisville(COLUMN)29(COLUMN)38 Memphis(COLUMN)27(COLUMN)62 Miami Beach(COLUMN)42(COLUMN)67 Midland(COLUMN)35(COLUMN)78 Milwaukee(COLUMN)9(COLUMN)32 Mpls. St. Paul(COLUMN)15(COLUMN)51 Neshville(COLUMN)21(COLUMN)49 New Orleans(COLUMN)35(COLUMN)69 New York(COLUMN)25(COLUMN)32 Norfolk(COLUMN)29(COLUMN)41 North Platte(COLUMN)20(COLUMN)71 Oklahoma City(COLUMN)37(COLUMN)75 Omaha(COLUMN)24(COLUMN)72 Orlando(COLUMN)33(COLUMN)62 Philadelphia(COLUMN)27(COLUMN)31 Phoenix(COLUMN)53(COLUMN)85 Pittsburgh(COLUMN)9(COLUMN)24 Portland, Me.(COLUMN)22(COLUMN)31 Portland, Ore.(COLUMN)42(COLUMN)53 Providence(COLUMN)28(COLUMN)34 Raleigh(COLUMN)23(COLUMN)42 Rapid City(COLUMN)30(COLUMN)65 Reno(COLUMN)33(COLUMN)45 Richmond(COLUMN)26(COLUMN)44 St. Louis(COLUMN)16(COLUMN)51 St. Prbg. Tampa(COLUMN)33(COLUMN)64 Salt Lake City(COLUMN)32(COLUMN)63 San Antonio(COLUMN)38(COLUMN)73 San Diego(COLUMN)57(COLUMN)68 San Francisco(COLUMN)51(COLUMN)59 San Juan, P.R.(COLUMN)71(COLUMN)87 St. Ste. Marie(COLUMN)10(COLUMN)19 Seattle(COLUMN)45(COLUMN)57 Shreveport(COLUMN)34(COLUMN)77 Sioux Falls(COLUMN)22(COLUMN)64 Spokane(COLUMN)30(COLUMN)47 Syracuse(COLUMN)15(COLUMN)25 Tucson(COLUMN)47(COLUMN)81 Tulsa(COLUMN)34(COLUMN)79 Washington(COLUMN)27(COLUMN)39 Wichita(COLUMN)27(COLUMN)76(END TABLE)