QUIET WEATHER RETURNS TO THE NORTHEAST -- Residents of the Northeast had a respite from the inclement weather as the storm system that plagued them finally moved northeastward into the Canadian Maritimes. A high pressure cell moved in behind the departing storm system and trailing cold front. By late Wednesday night an elongated ridge of high pressure, albeit weak, extended along the Atlantic Seaboard from New England to the Carolinas. The cloud cover that had been over much of the Northeast broke to provide sunny skies and mild temperature readings. The afternoon maximum temperature at Bridgeport, CT reached 53 degrees, tying a record high for the date. However, the experience was short-lived, since the next storm system is expected to move into the region from the Midwest on Thursday.
THE CLIPPER MOVES EASTWARD -- A small storm system, called an "Alberta Clipper", moved eastward along the U.S. Canadian border from southern Alberta. By late Wednesday night, one low pressure system was located over the western end of Lake Superior, with several other low pressure centers located in central Ontario along a cold front. Another cold front extended southward through the Mississippi Valley from the main low pressure center over Lake Superior. A secondary cold front was stretched southwestward across Minnesota into South Dakota before curving northwestward, crossing eastern Montana and becoming a stationary front along the Canadian Rockies.
A region of precipitation associated with this system was detected across the western Great Lakes, stretching from Lake Superior southward to southern Illinois. Snow was falling across Michigan's Upper Peninsula and northern Wisconsin, while rain was found to the south and over most of Lower Michigan.
Windy conditions were found to the west of the storm system, associated with a relatively strong pressure gradient -- as indicated by the tightly packed isobars appearing on the Wednesday night surface analysis charts. Strong winds from the northwest, reaching speeds between 30 to 40 mph, with gusts to 45 mph were reported near Rochester in southeastern Minnesota, where wind advisories were posted.
This storm system is expected to have moved east of Lake Superior by Thursday morning.
A WIND STORM OF MAJOR PROPORTIONS -- As the Alberta Clipper was organizing and beginning its eastward trek on Tuesday evening, a very strong pressure gradient was developing between high pressure over the Great Basin and the low pressure system. With an increased pressure gradient, the winds increased correspondingly, especially over the Rockies where the mountain barriers served to channel the wind. Numerous locations in the northern Rockies reported wind gusts that reached in excess of 100 mph, such as in Colorado at Wondervu, where a gust reached 119 mph and at Boulder where some damage was reported (see Reports below). Cheyenne, WY reported a gust to 71 mph, a record for the month of February. Damaging winds were also reported across Montana.
THUNDERSTORMS OVER THE GULF COASTAL STATES -- Thunderstorms developed along the southern terminus of a nearly stationary cold front that ran east-west across the Southeast on Wednesday night. The area covered by these thunderstorms extended from near Jacksonville in north Florida westward through the Florida Panhandle to the coastal regions of Mississippi. Earlier in the evening, several of the thunderstorms over southern Mississippi turned severe as the golfball sized hail that fell was above one of the criteria set for a severe thunderstorm.
FLOODING ON THE MISSISSIPPI -- A combination of factors, to include heavy rains in the various watersheds feeding into the tributaries, as well as warm weather that caused rapid snowmelt of a substantial snowpack, have been responsible for the Mississippi River to rise above flood stage approximately 100 miles upstream from Memphis, TN. The river was continuing to rise, with the crest anticipated to occur on Friday. The crest is expected to move down river, reaching Vicksburg, MS by mid February.
THE NEXT STORM IS ABOUT TO ENTER -- While the center of the storm remained several hundred miles out over the Pacific Ocean to the west of the entrance to the Strait of Juan de Fuca, the cold front associated with this potent storm system had swept inland across western Washington State and Oregon. Strong winds and heavy precipitation preceded the frontal passage. As a result, a high wind watch was in effect for the coastal regions of Oregon and Washington, to include portions surrounding Puget Sound for sustained winds reaching 40 mph, with gusts to 60 mph. Marine storm warnings were posted for the coast from Cape Flattery, WA to Cape Lookout, OR and gale warnings from Cape Lookout to Point St. George, CA. Snow advisories were issued for the Olympics and the Washington Cascades for as 8 inches of new snow. Flood warnings were continued for several rivers in western Washington State. Farther inland, Snow and blowing snow advisories were posted for the Blue Mountains of eastern Oregon and Washington, as well as the mountains of western Montana and the Idaho Panhandle through Thursday.
By Thursday morning the cold front is forecast to have moved eastward, with the northern portions of the front reaching the mountains of western Montana and the southern portion of the front approaching the San Francisco Bay area.
Clouds and precipitation in advance of a weak storm system were approaching Southern California late Wednesday night. The rain is expected to reach San Diego by dawn on Thursday.
YESTERDAY'S TEMPERATURE EXTREMES ACROSS THE CONTINENTAL US -- The lowest temperature on Wednesday was 7 degrees at Alamosa, CO and Wednesday's highest temperature was 90 degrees at Needles, CA.
ALASKAN WEATHER -- The ridge of high pressure associated with the arctic air mass that has resided over the northern half of Alaska for the last week remained in place on Wednesday afternoon. The ridge line, or axis of highest pressure, ran from Russia's Chukchi Peninsula southeastward to the eastern Alaska Peninsula. The clockwise circulation around the high continued to produce northerly winds across a large portion of mainland Alaska. The effect of the winds were especially noticeable in the mountain passes of the Brooks and Alaska Ranges. On Wednesday morning, Anaktuvuk Pass in the Brooks Range reported an air temperature of 26 degrees below zero. Winds of 19 mph produced a wind-chill equivalent temperature of 73 degrees below zero, as well as reduced visibility in blowing snow and ice fog. Wind-chill warnings were issued for the pass through Thursday.
A strong storm system located south of Dutch Harbor in the central Aleutians produced clouds, fog, snow and blowing snow due to windy conditions over the Pribilofs and the Aleutians, with gusts ranging between 35 and 45 mph. Dutch Harbor had a gust of 52 mph, while visibilities due to the fog and snow were less than one-half mile. Blizzard warnings were in effect for Wednesday night for St. Paul Island and Cold Bay. Wind chill advisories for wind-chill equivalent temperatures reaching 60 to 70 degrees below zero were issued for Bristol Bay and the Kuskokwim Delta.
Another weakening storm system was nearly stationary over the northeastern Gulf of Alaska to the west of Yakutat. Clouds and light snow were found from southeast Alaska through the Panhandle. A weak trough of low pressure was also found along the Arctic Slope coastal region. Snow and fog were reported across the region.
The state's lowest overnight temperature on Wednesday was 58 degrees below zero at Tanana while the highest temperature in Alaska as of mid-afternoon was 37 degrees at Annette Island, Hydaburg and Metlakatla.
King Salmon had a record low temperature of 34 degrees below zero on Wednesday morning. This past week's "Cold Snap of 1999" had many locations across northern Alaska with temperatures that fell to 40 degrees below zero or lower. Numerous record low temperatures were also reported The lowest temperature during this arctic outbreak was at Chandalar Lake on Friday 29 January 1999 with a reading of 74 degrees below zero, which was also the all-time lowest temperature of record at that location.
HAWAIIAN WEATHER -- The strong high pressure system located to the north-northeast of Hawaii was beginning to slowly weaken and move closer to the islands on Wednesday. As a result, the prevailing trade winds over the islands that had reached peak wind speeds between 20 to 35 mph during the day were expected to weaken very slowly over the next several days. Trade showers were also anticipated to remain active. As a result of the strong trade winds, gale warnings were posted for the channels between the islands, while small craft advisories remained in effect for coast waters. A high surf advisory was posted for the northwest and east shores as a result of the swell that developed in the long trade wind fetch to the east of the islands. A wind advisory was also in effect for Kohala District on the Big Island and Haleakala on Maui.
REPORT FROM THE FIELD -- Katy Ginger, one of the meteorologists in Boulder, CO with the COMET Project that provides the data network support to Online Weather Studies, reported that most of Boulder lost electrical power last night because of the sustained hurricane-force winds that gusted to 125 mph. As a result, some of the maps and other products appearing on the Online Weather page were delayed this morning.
AIR MASSES -- For an additional explanation of air masses and their properties, call up the Thursday's optional Supplemental Information .
From the files of the Aviation Weather Center, Kansas City, MO and Intellicast
Return to Online Weather Homepage
Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 1999, The American Meteorological Society.