Washington: Today - Mostly cloudy, high in 60s, low in 40 Chance of rain is near zero through tonight. Winds will be northwesterly at 10 mph. Monday - Sunny and mild, high near 70.

Maryland and Virginia: Today - Mostly cloudy, high near 70, low from the 30s in the mountains to 50 near the Bay. Monday - Mostly sunny and mild, high in the 60s to low 70s.

Lower Potomac and Chesapeake Bay: Today - Fair, visibility more than five miles. Winds will be variable less than 8 knots. Waves in unprotected waters will be less than one foot.

Extended Area Outlook for Tuesday through Thursday: There will be a chance of some rain late Tuesday or Wednesday, otherwise partly cloudy. Highs will average from the mid 50s to mid 60s with lows in the 30s and 40s. Normal Washington temperatures for the period will be a high of 61 and a low of 41.

West Virginia: Today - Mostly sunny and mild, high in the 60s to near 70, low in the 30s and low 40s. Monday - Partly cloudy, high in the 60s to near 70.

The Nation Yesterday: An intense fast moving low pressure system brought very strong winds to the eastern slopes of the northern Rockies. Gusts of 80 mph at Great Falls, Mont., resulted in power outages as well as a few roofs being blown off buildings. Wind gusts of 75 to 80 mph were also recorded at Havre and Livingston, Mont. High wind eastern slopes of the Montana Rockies as 40 to 50 mph gusts are expected to continue through the day. Wind warnings have also been posted for Wyoming, the western half of North Dakota, and western third of South Dakota where strong westerly winds with gusts to 50 mph. Farther west, in the Cascade Mountains of Washington, a travelers advisory was issued for snow and blowing snow during the day decreasing to snow showers tonight. Meanwhile the threat of wind diminshed over the Atlantic Coast. Gale force winds, which had produced rough surf and beach erosion along the coasts of Virginia and eastern Florida, were subsiding today as the low pressure system off the North Carolina coast continued to move northward over the Atlantic. Winds and seas will gradually return to normal levels. Dry weather prevailed over much of the nation. A few showers lingered along the middle Atlantic Coast, northern Minnesota, and North Dakota while thundershowers were found in the western half of Texas.

The national weather forecast for today - rainshowers will occur from the north Pacific Coast into the northern Plateau. Showers will also be scattered through the lower Missouri Valley and upper Great Lakes region with thundershowers in the southern Plains. Skies will be mostly sunny from California into the southern Plateau, over Montana, and from the lower Mississippi and Tennessee valleys through the middle and south Atlantic Coast. Elsewhere partly cloudy to cloudy conditions will prevail. Cool temperatures are forecast from the north Pacific coast across the northern Rockies into the northern Plains and along the western half of the remainder of the Plains and New Mexico. The rest of the nation will enjoy seasonably mild to warm temperatures.

Almanac Data for today: The sun rises 6:39 a.m., sets 5:04 p.m.; moon rises 11:19 a.m., sets 9:45 p.m. Tides: High, 11:04 a.m. and 11:33 p.m.; low, 5:41 a.m. and 5:46 p.m. High and low tides at the following locations may be obtained by subtracting the hours indicated (3 1/4), Bloody Point Lighthouse (4 1/2), Deale, Md. (4 1/2), Colonial Beach (5 1/4), Norfolk (1), Virginia Beach (3/4), Solomons Island (6 1/4), Point Lookout (7).

The Council of Government's Air Quality Index for yesterday showed the high reading in the Washington area during the 10 a.m. period was 10 for the pollutant, carbon monoxide. Index values between 0 and 25 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 remain good.

The National Weather Service forecasts the Potomac River stage at Little Falls should remain near 2.9 feet today. Local Temp., Humidity(TABLE) Time(COLUMN)T(COLUMN)H 12 midnite(COLUMN)55(COLUMN)72 1 a.m.(COLUMN)53(COLUMN)75 2 a.m.(COLUMN)52(COLUMN)80 3 a.m.(COLUMN)53(COLUMN)83 4 a.m.(COLUMN)53(COLUMN)83 5 a.m.(COLUMN)54(COLUMN)80 6 a.m.(COLUMN)54(COLUMN)80 7 a.m.(COLUMN)54(COLUMN)80 8 a.m.(COLUMN)54(COLUMN)83 9 a.m.(COLUMN)55(COLUMN)80 10 a.m.(COLUMN)56(COLUMN)77 11 a.m.(COLUMN)57(COLUMN)75 12 noon(COLUMN)57(COLUMN)75 1 p.m.(COLUMN)57(COLUMN)78 2 p.m.(COLUMN)59(COLUMN)75 3 p.m.(COLUMN)59(COLUMN)75 4 p.m.(COLUMN)59(COLUMN)72 5 p.m.(COLUMN)58(COLUMN)64 6 p.m.(COLUMN)59(COLUMN)55(END TABLE) Temperatures ending 7 a.m. (EST) yesterday:(TABLE) City(COLUMN)H(COLUMN)L Albany(COLUMN)64(COLUMN)32 Albuquerque(COLUMN)57(COLUMN)46 Amarillo(COLUMN)72(COLUMN)54 Anchorage(COLUMN)27(COLUMN)24 Asheville(COLUMN)72(COLUMN)31 Atlanta(COLUMN)77(COLUMN)40 Atlantic City(COLUMN)60(COLUMN)50 Austin(COLUMN)82(COLUMN)57 Baltimore(COLUMN)69(COLUMN)49 Billings(COLUMN)63(COLUMN)45 Birmingham(COLUMN)79(COLUMN)40 Bismarck(COLUMN)63(COLUMN)26 Boise(COLUMN)67(COLUMN)52 Boston(COLUMN)58(COLUMN)42 Brownsville(COLUMN)86(COLUMN)68 Buffalo(COLUMN)64(COLUMN)44 Burlington(COLUMN)58(COLUMN)36 Casper(COLUMN)66(COLUMN)38 Charleston, S.C.(COLUMN)67(COLUMN)60 Charleston, W.Va.(COLUMN)69(COLUMN)38 Charlotte(COLUMN)71(COLUMN)49 Cheyenne(COLUMN)63(COLUMN)33 Chicago(COLUMN)74(COLUMN)60 Cincinnati(COLUMN)72(COLUMN)42 Cleveland(COLUMN)70(COLUMN)40 Columbia, S.C.(COLUMN)73(COLUMN)53 Columbus(COLUMN)70(COLUMN)39 Dal. Ft. Worth(COLUMN)86(COLUMN)55 Dayton(COLUMN)71(COLUMN)42 Denver(COLUMN)67(COLUMN)37 Des Moines(COLUMN)76(COLUMN)46 Detroit(COLUMN)70(COLUMN)41 Duluth(COLUMN)70(COLUMN)28 El Paso(COLUMN)71(COLUMN)51 Fairbanks(COLUMN)08(COLUMN)01 Fargo(COLUMN)69(COLUMN)26 Flagstaff(COLUMN)49(COLUMN)43 Great Falls(COLUMN)61(COLUMN)54 Hartford(COLUMN)63(COLUMN)28 Helena(COLUMN)54(COLUMN)39 Honolulu(COLUMN)82(COLUMN)64 Indianapolis(COLUMN)75(COLUMN)42 Jackson, Miss.(COLUMN)83(COLUMN)43 Jacksonville(COLUMN)72(COLUMN)44 Juneau(COLUMN)40(COLUMN)36 Kansas City(COLUMN)82(COLUMN)56 Las Vegas(COLUMN)81(COLUMN)55 Little Rock(COLUMN)80(COLUMN)58 Los Angeles(COLUMN)80(COLUMN)56 Louisville(COLUMN)72(COLUMN)45 Memphis(COLUMN)81(COLUMN)51 Miami Beach(COLUMN)82(COLUMN)62 Midland-Odessa(COLUMN)70(COLUMN)54 Milwaukee(COLUMN)73(COLUMN)51 Mpls-St. Paul(COLUMN)74(COLUMN)44 Nashville(COLUMN)74(COLUMN)39 New Orleans(COLUMN)83(COLUMN)51 New York(COLUMN)63(COLUMN)48 Norfolk(COLUMN)66(COLUMN)54 North Platte(COLUMN)76(COLUMN)26 Oklahoma City(COLUMN)81(COLUMN)56 Omaha(COLUMN)74(COLUMN)47 Orlando(COLUMN)76(COLUMN)52 Philadelphia(COLUMN)67(COLUMN)47 Phoenix(COLUMN)75(COLUMN)53 Pittsburgh(COLUMN)65(COLUMN)38 Portland, Me.(COLUMN)61(COLUMN)32 Portland, Ore.(COLUMN)61(COLUMN)48 Providence(COLUMN)62(COLUMN)37 Raleigh(COLUMN)71(COLUMN)55 Rapid City(COLUMN)68(COLUMN)37 Raleigh(COLUMN)71(COLUMN)55 Rapid City(COLUMN)68(COLUMN)37 Reno(COLUMN)65(COLUMN)28 Richmond(COLUMN)71(COLUMN)50 St. Louis(COLUMN)76(COLUMN)59 St. Prbg.-Tampa(COLUMN)77(COLUMN)50 Salt Lake City(COLUMN)63(COLUMN)45 San Antonio(COLUMN)83(COLUMN)60 San Diego(COLUMN)74(COLUMN)59 San Francisco(COLUMN)70(COLUMN)53 San Juan(COLUMN)92(COLUMN)76 St. Ste. Marie(COLUMN)66(COLUMN)45 Seattle(COLUMN)57(COLUMN)44 Shreveport(COLUMN)83(COLUMN)51 Sioux Falls(COLUMN)76(COLUMN)33 Spokane(COLUMN)51(COLUMN)45 Syracuse(COLUMN)61(COLUMN)39 Topeka(COLUMN)81(COLUMN)51 Tucson(COLUMN)67(COLUMN)48 Tulsa(COLUMN)85(COLUMN)54 Washington(COLUMN)72(COLUMN)52 Wichita(COLUMN)79(COLUMN)56(END TABLE)