WEATHER OVER THE WEEKEND -- A stormy weather pattern continued across the Pacific Northwest this weekend as more storms made landfall then moved inland at about a day and a half interval. Strong winds that gusted to 80 mph and heavy rain pounded the region. High winds on Saturday near Seattle, WA caused some minor damage. Flooding rains fell in Washington and Oregon. Even in northern California more than 7 inches of rain fell over the weekend. The mountains of northern California, Oregon and Washington also had heavy snow, with several places having several feet of new snow cover. Whiteout conditions as a result of the heavy snow and winds were reported Saturday in Idaho.
In addition to the storms moving across the Pacific Northwest, another storm moved eastward across the southern United States. At the beginning of the weekend this system had produced rain across southern California and snow in the mountains of the Southwest. By late Saturday, a low had moved east of the Rockies, and eventually began moving to the northeast toward the lower Great Lakes by Sunday. Ahead of this system, warm air invaded the Plains with unseasonably mild temperatures. On Friday a record high temperature of 64 degrees was set at Omaha (Eppley), NE. Several other locations had record high minimum temperatures for Friday, to include Amarillo, TX, with a low temperature of only 44 degrees, and Grand Island had 32 degrees, both record high minimum temperatures, for their respective cities. Numerous high temperature records were also set on Saturday at Atlanta, GA; Birmingham and Huntsville, AL; Jackson, MS; New Orleans, LA and Joplin, MO.
By Saturday afternoon thunderstorms developed over the Southern Plains in association with the storm system. On Saturday, some thunderstorms over Oklahoma, north Texas, Arkansas and Tennessee turned severe, with damaging wind and large hail. On Sunday the storm system continued toward the Midwest, producing heavy rainfall over the Ohio Valley, but snow in the Upper Great Lakes.
On Sunday afternoon high temperatures across much of the continental United States were well above the long-term average highs for this time of year. Many locations had high temperatures that were 10 to 20 degrees above the local average high. The only exceptions were over the Northeast, where slightly below average highs were reported, as well as the Pacific Coast, where temperatures were 10 degrees below average. More than a dozen record high temperatures were either tied or set in a region that stretched from Texas to the Carolinas. San Antonio, TX had a daily record high temperature of 84 degrees, followed closely by Jackson, MS with a reading of 81 degrees.
WEATHER FOR THE START OF THE NEW WEEK -- Two major regions of precipitation were found across the nation on Sunday night. One area was located in the Northeast, associated with a storm system that was moving eastward through the Middle Atlantic States from the Midwest, where earlier in the day Detroit, MI had received approximately 3 inches of snow. This storm system consisted of two low pressure centers, with the primary low situated over central Pennsylvania and a secondary low that developed to the southeast over the Delmarva Peninsula. A warm front extended eastward from the secondary center out over the Atlantic Ocean, while a cold front trailed southwestward along the Appalachians to the Tennessee and lower Mississippi Valleys. Snow and ice pellets (sleet) were falling in the cold air on the north side of the storm system across northern Pennsylvania, New York State and into New England, while a change-over to rain was found along the warmer south side of the system. The southern secondary low pressure center is forecast to intensify and become the primary storm as it moves out over the Atlantic Ocean early Monday. As much as 6 inches of snow are expected to fall by Monday noon in a band from the Poconos in northeast Pennsylvania, across the lower Hudson Valley into southern New England as the system moves eastward and draws an onshore flow of moist air from off the Atlantic into the colder interior sections of the Middle Atlantic and southern New England. Winter storm warnings were issued for the inland regions, while a winter weather advisory was posted for the New York metropolitan area, where proximity to the relatively warm Atlantic was expected to reduce the amount of snow totals. This system is expected to clear the region later on Monday.
The other area of precipitation was found along a large portion of the West Coast, stretching from central California northward to Canada, and inland into the Great Basin. Most of the precipitation fell as rain at lower elevations, while snow was reported at the higher elevations, from the Sierras, the Cascades and the mountains in Idaho and Montana. Some areas of northern California had significant rains during the weekend. This precipitation was in part due to the westerly or onshore winds that reach the mountain barriers along the Pacific Northwest, and also in part due to the next storm system approaching the Pacific Northwest. The moist air being forced upward along the Coastal Range, the Olympics and the Cascade cools and produces clouds and precipitation. The approaching storm system as of late Sunday night was several hundred miles off the Washington coast. Strong winds from the southwest were reported along the coast, with speeds up to 65 mph along the Oregon headlands. Gale warnings were to be issued for winds between 39 and 54 mph along the Washington, Oregon and northern California coasts. This storm system is forecast to make landfall on Monday and continue sweeping inland, carrying the accompanying precipitation eastward. Cold air being drawn into the west side of the storm could bring snow levels down to less than 1000 feet above sea level, especially over Seattle, WA. Winter storm warnings were posted for the Cascades of Washington and Oregon and the mountains of northern California for as much as 12 inches of snow. The Wasatch Mountains in Utah were also under winter storm warnings.
A weak trough of low pressure was located over the northern Rockies and western high Plains. This trough line, constituting a shift in the near-surface winds, enhanced cloudiness and some light precipitation, should move eastward on Monday, reaching the upper Mississippi Valley on Monday. Some light freezing precipitation may fall over central Minnesota.
Elsewhere, clear skies and a warm, humid tropical air mass have produced dense fog along the Gulf Coast on Sunday night.
TEMPERATURE EXTREMES IN THE COTERMINOUS U.S. -- The lowest temperature on Sunday was 4 degrees below zero at Eagle River, WI, while Sunday's highest temperature was 86 degrees at McAllen, Alice and Kingsville, TX.
ALASKAN WEATHER -- The arctic air mass that has kept Alaska in a major "cold snap" for nearly the last two weeks remained over the state on Sunday. This air mass was associated with an intense ridge of high pressure that extended from Eastern Russia into mainland Alaska. To date, the winter of 1998-99 has been the coldest in Alaska in ten years. On Friday morning Galena tied a record low for the dated with a reading of 57 degrees below zero, while Denali Park Headquarters had 54 degrees below zero, tying the lowest temperature ever at that location. The 52 degree below zero at the University of Alaska set a new record low for February. Also on Friday, Kodiak saw a record low temperature of zero degrees, the third day in a row where a record low was either tied or broken. On Saturday clouds helped produce some moderating temperatures across the interior that ranged between 20 and 30 degrees below zero. However, clear skies signaled a return to very cold temperatures across interior Alaska. On Sunday morning, McGrath recorded a minimum temperature of 53 degrees below zero, a record for the date. With weak February sun, the temperature at McGrath soared 17 degrees in four hours Sunday, rising from 53 degrees below zero to 36 below.
In addition to the low air temperatures, the winds across the north and northwestern corner of the state produced wind-chill equivalent temperatures that were as low as 80 degrees below zero. Consequently, wind-chill warnings were posted for the North Slope, St. Lawrence Island and the Seward Peninsula, to include the Kotzebue Sound and Norton Sound regions.
Clouds and light precipitation were reported along the southern coasts of the state, stretching from the Aleutians eastward to the southern Panhandle, the result of several storm systems. One weakening low pressure cell was relatively stationary and centered in the northern Gulf of Alaska, east of Prince William Sound. The other system was moving eastward across Bristol Bay and the Alaska Peninsula. The strong pressure gradient between the high pressure system to the north and low pressure systems across the southern part of the state produced some strong winds. Cold Bay had gusts to 45 mph, producing blizzard conditions as visibility was reduced to less than a mile in blowing snow. Kodiak had gusts to 57 mph.
As of late Saturday, Yakutat had received more than 70 inches of snow, from continuous snowfall that started one week ago on 30 January. By Sunday morning, another 20 inches had fallen. Snow depth was over 6 feet, but winds gusts produced 15 foot high drifts. While northern Alaska was well below zero, the southern Panhandle had temperatures that were in the "balmy" 30s -- above zero on Sunday.
The overnight lowest temperature in Alaska as of Sunday morning was 65 degrees below zero recorded at Galena. The mid-afternoon highest temperature for the state was 37 degrees at Annette.
HAWAIIAN WEATHER -- The moderate northeast trade winds, with speeds between 15 and 20 mph, continued to cross the islands on Sunday afternoon as a large high pressure ridge remained to the north of Hawaii. These winds should continue along with the widely scattered trade showers through mid week. At that time, the high is expected to weaken and move closer to the islands. Small craft advisories remained in effect for all Hawaiian waters.
SO YOU WANT WEATHER DATA? A national network of several thousand weather observation stations continually monitors the near surface weather conditions across the country. You can access essentially current weather data from around your state or the United States from the portion of the Online Weather Homepage marked as State Surface Data-Text. Consult the Monday optional Supplemental Summary Information for additional information as to the data and how you can interpret these data.
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.