WELCOME TO THE FIRST WEEK OF THE ONLINE WEATHER STUDIES -- The Daily Weather Summary file will describe the current weather pattern across the U.S. Additional Supplemental Information Files will provide optional background material.
INCLEMENT WEATHER PERSISTS IN THE NORTHEAST -- A slow moving storm system and accompanying precipitation shield continued to produce inclement weather across much of the Northeast on Tuesday. By late night, the low pressure center was located over the Delaware Valley between New York State, New Jersey and Pennsylvania. A warm front extended eastward across southern New England, while a cold front ran southward just offshore of the Atlantic Seaboard to the central Florida Peninsula. The storm system is expected to continue to the northeast, reaching the coast of Maine by Wednesday morning.
A large precipitation shield surrounded the low pressure center, with the greatest intensity extending eastward across New England and southward out to sea along the cold front, as of Tuesday night. Precipitation near the coast was falling mainly as rain, since temperatures were sufficiently warm. Farther inland, freezing rain was reported across portions of New England, while snow fell across northern Maine and the high terrain of the New Hampshire and Vermont.
Fog was developing in the river valleys of New England and the Middle Atlantic States. A dense fog advisory was issued for the New York City metropolitan area for a fog with visibilities of one quarter mile anticipated.
A cold front that had been situated over the high plains of the Dakotas on Monday night moved quickly to the Northeast on Tuesday. This front trailed southward from a low pressure system over Ontario that also had moved southeastward. Because of clear skies to the west of the temperatures behind the front were at least as high as those to the east. By Tuesday evening, this cold front had almost dissipated across the Ohio Valley.
Flood warnings remained in effect for several rivers in the Hudson Valley of southern New York State and in Massachusetts. Previous heavy rains, combined with ice jams have caused the rivers to flood.
A CLIPPER MOVES EASTWARD -- A storm system located in southern Alberta on Tuesday night was forecast to move eastward, paralleling the U.S.-Canadian border on Wednesday. Because of the region where formed and its expected rapid motion, reaching the northeast sections of North Dakota, this system could be called an "Alberta Clipper". A warm front extended eastward from the low, while a cold front stretched to the southwest, reaching northern California. Light snow was found to the north of this system. A region of precipitation, to include rain, freezing rain and snow developed quickly to the south of the system across the northern Rockies and the western Plains.
WINDY CONDITIONS ACROSS THE ROCKIES -- A strong pressure gradient, or difference in pressure, continued to intensify between the high pressure cell over the Great Basin and the storm system to the north of the U.S.-Canadian border in the western Prairie Provinces. This intense pressure gradient was reflected in the relatively tight packing between isobars appearing on the surface weather analysis charts for Tuesday night. As a result of the pressure gradient, strong northwesterly winds continued to flow across northern and central Rockies on Tuesday. On Tuesday morning, Livingston, MT reported 79 mph gusts, while an automatic weather station some 40 miles to the northwest of Rawlins, WY had a 93 mph gust. High wind warnings were posted for many locations to include the region in Colorado around Pikes Peak, where sustained winds were anticipated to reach 40 to 60 mph, with gusts to 80 mph. High wind watches were also found across the Dakotas for Wednesday night.
Residents to the east of the mountains should expect to experience warm conditions as the winds descend the eastern slopes, in what could be termed a "Chinook". Sinking air is compressed due to higher pressure at lower altitudes, with the compression causing an increase in temperature.
WET WEATHER IN THE PACIFIC NORTHWEST -- While one storm moved through the Pacific Northwest on Tuesday, a new storm in the series was moving eastward across the Pacific, aimed for the Washington Coast. In addition a strong onshore wind flow from the west continued. Heavy rains were reported across the region, with as much as 4 inches of rain reported. As much as result, flood warnings.
The precipitation continued along the coastal regions of western Washington, Oregon and northern California. Snow fell across the mountains of eastern Washington, Oregon, Idaho and western Montana, with as much as 10 inches reported.
On Tuesday morning, the overnight minimum temperature at Oakland, CA fell to a daily record low of 38 degrees. On Tuesday afternoon Wenatchee, WA set a record high temperature of 51 degrees.
TEMPERATURE EXTREMES ACROSS THE LOWER 48 -- On Tuesday, the lowest temperature reported in the continental U.S. was 8 degrees below zero at Craig, CO. The highest temperature on Tuesday was 82 degrees at McAllen, TX and Punta Gorda, FL.
ALASKAN WEATHER -- The arctic high pressure system that has persisted along the west coast of Alaska for nearly one week shifted westward, but it continued to maintain its grip over a large portion of the state on Tuesday. Winds circulating in a clockwise direction around the high continued to bring cold air across northern Alaska. Winds from the north continued across the Alaska Range with wind speeds between 20 to 35 mph. On Tuesday morning the temperature at Galena fell to a low of 64 degrees below zero, a record low for the month of February. The low at McGrath of 61 degrees below zero tied the February record. Elsewhere, the Denali Park Headquarters tied a daily record low of 43 degrees below zero, while King Salmon fell to a daily record low of 33 degrees. Wind-chill warnings were in effect for the passes in the Alaska Range and for the Upper Tanana Valley where wind-chill equivalent temperatures were expected to fall to near 90 degrees below zero.
A storm system moved from the Gulf of Alaska onshore east of Cordova. Clouds and precipitation were found along coastal regions from the Panhandle through southeast Alaska. In relatively warm air, Annette reported nearly 0.6 inch of rain, while other locations over the southeast had freezing rain, ice pellets (sleet) and snow.
Tuesday morning's lowest temperature in the state was 60 degrees below zero at McGrath. As of mid-afternoon, the state's highest temperature was 43 degrees at Metlakatla.
HAWAIIAN WEATHER -- A large high pressure system continued to strengthen and move to a position north of the Hawaii on Tuesday. As a result, the trade winds on the southern flank of this high were expected to increase to between 20 and 35 mph across the islands on Wednesday. Afternoon trade showers should increase especially on the windward slopes of the islands. Small craft advisories remain in effect for state waters.
The Big Island has experienced some chilly weather recently with winter storm warnings for the summits, and on Monday, when the afternoon high at Hilo was only 74 degrees, tying the coldest maximum temperature for the date.
From the files of the Aviation Weather Center, Kansas City, MO and Intellicast
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Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 1999, The American Meteorological Society.