WEATHER OVER THE WEEKEND -- Much of the nation experienced relatively tranquil weather over the weekend. A slow moving storm system that had produced fairly strong thunderstorms and heavy rains across Texas and heavy snow in the southern Rockies near the end of last week continued to move eastward from its position over central Texas late Thursday night. Snow continued across portions of Kansas into Friday. Along the Gulf coast, heavy rains, in places reaching 4 inches near Houston, caused some localized flooding. By evening the storm center had moved eastward to east Texas and by the next morning its position was over Mississippi. The system began to curve toward the northeast, reaching northeastern Alabama by Saturday evening and northern Georgia by Sunday morning. Rain showers and thunderstorms accompanied this low eastward and then northeastward. Thunderstorms produced large hail in the Carolinas. By Sunday afternoon, severe thunderstorms developed in the warm sector to the southeast of the storm system and produced hail and high winds. A dozen hail reports were made from the Piedmont of the Carolinas and 60 mph thunderstorm gusts produced wind damage from South Carolina.
Farther north, a weak storm system with little available moisture moved eastward along the US-Canadian border. On Friday morning this system, which could be classified as an Alberta Clipper for its location of origin and speed, developed along the eastern slopes of the Canadian Rockies, then quickly moved eastward across the Prairie Provinces, reaching the Manitoba Lakes by Friday night. A cold front, with little precipitation, moved southeastward across the Dakotas. By Saturday night the low pressure center, which was located over Lake Superior, was beginning to occlude as the cold front quickly moved to catch and merge with the warm front, forming an occluded front. By Sunday morning a secondary low was beginning to form over Lake Huron. Clouds and lightly scattered precipitation developed as more moisture was tapped from the east.
A storm system moved into the California from off the Pacific Ocean on Friday, spreading clouds and precipitation across much of coastal California from San Francisco to Los Angeles. Snow fell across the higher elevations. This storm system moved into the Great Basin and weakened.
Unseasonably warm weather stretched from the Plains across the Plains into the Pacific Northwest. Sunday afternoon high temperatures were as much as 20 degrees above the average highs over the Rocky Mountain States. On Friday record temperatures were broken at Dickinson, ND (71 degrees) and in Washington State at Wenatchee (68 degrees) and Quillayute (66 degrees). The record high temperature was tied at Pocatello, ID (71 degrees). On Saturday, the daily record was tied at Elko, NV (70 degrees), while record high temperatures were set at Spokane, WA (70 degrees); at Pocatello, ID (72 degrees) and in Wyoming at Rawlins (65 degrees) and Rock Springs (63 degrees). On Sunday afternoon Pueblo, CO reached a record high temperature of 81 degrees.
On Saturday a wind gust, or possible gustnado, caused damage in the Snake Valley of Idaho near Boise.
WEATHER FOR STARTING THE NEW WEEK -- As of late Sunday night a large area of precipitation fell across the Northeast extending from the Chesapeake Bay northward to southern Quebec. Rain fell along the coast, while inland over the higher terrain of the Appalachians, snow fell. This precipitation was in association with the storm system moving eastward from the Great Lakes and the other storm system that was moving northward along the Atlantic Seaboard. The Great Lakes system had a low pressure center located in Ontario to the east of Georgian Bay and an occluded front that curved southeastward into central Pennsylvania, which continued southwestward as a cold front into the Tennessee Valley. Some lake-enhanced snowshowers continued across northern sections of Lower Michigan and northern Ohio on northwesterly winds. The Atlantic Coast storm was moving northward and was located over the Piedmont of North Carolina with a warm front extending to the northeast across Tidewater Virginia and a cold front that trailed southward out over the Atlantic Ocean and then crossing south Florida. Thundershowers were found over coastal regions of North Carolina and into Virginia.
Heavy rain was falling in many of the major metropolitan areas in the Northeast. Flooding of some areas was imminent. At least six inches of snow has already fallen over portions of northern Pennsylvania. In addition to the precipitation, winds began to increase in speed, gusting to 39 mph in New York City. As a result, gale warnings for winds ranging from 39 to 54 mph were in effect from Fenwick Island, DE to Watch Hill, RI and storm warnings for higher winds continued northward to Eastport, ME. The southeasterly winds could also produce coastal flooding as water is piled up along coastal sections of southern New England.
By Monday morning, these two storms are expected to merge, forming a single storm that should be positioned over the Hudson Valley of New York State. Most of the precipitation should have moved northward into New England and Upstate New York. Snow is expected at the higher elevations. High winds to 65 mph are expected to continue along coastal areas of southern New England.
A high pressure system was situated over northern Minnesota. Relatively tranquil, but cool weather conditions were found across the Upper Mississippi and northern Plains. The southern periphery of this cool air mass was marked by a cold front that extended from the Appalachians along the Tennessee Valley westward to northern Arkansas, where it became a stationary front that ran to the northwest across the Plains and then along the eastern slopes of the northern Rockies in Wyoming and Montana. A weak wave of low pressure had developed along the stationary front over Wyoming, with a region of precipitation detected in the Nebraska Panhandle. By Monday morning the high pressure system is expected to have moved southeastward reaching northwest Wisconsin. Precipitation should continue as scattered showers across the western Plains.
In the Pacific Northwest, some light rain fell around Puget Sound and the lower Columbia Valley. Light snow was also detected across northern Idaho and western Montana. A storm system that was located in the southern Gulf of Alaska on Sunday night was expected to approach the Pacific coast with a cold front by Monday morning. An increase in coastal precipitation is anticipated along the leading edge of the precipitation. Heavy surf advisories were posted along the California coast to as far south as Point Conception because of the large ocean swell generated by storms in the Gulf of Alaska.
TEMPERATURE EXTREMES IN THE COTERMINOUS U.S. -- The lowest temperature on Sunday was 6 degrees at Berlin, NH, while Sunday's highest temperature was 88 degrees at Presidio, TX.
ALASKAN WEATHER -- A very strong storm system, with a central pressure of 970 mb or slightly lower, was moving northeastward across the southern Bering Sea near Adak on late Sunday afternoon. An occluded front spiraled out from near the low pressure center, first curving toward the northeast, then toward the southeast, passing near Cold Bay. Because of the strong pressure gradient surrounding this storm system high winds were generated. A peak wind as of late Sunday afternoon was 98 mph at Shemya, while gusts to 86 mph were reported at Adak, 56 mph at St. George Island and 51 mph at St. Paul Island. As a result, storm warnings for winds higher than 54 mph were posted for most of the Bering Sea to as far north as St. Matthew Island. Snow accompanying the storm was found across the Bering Sea and portions of western Alaska. As a consequence of the snow coupled by the high winds, visibility was reduced to blizzard or near blizzard conditions. Therefore, blizzard warnings were in effect for the Pribilofs and the Kuskokwim Delta through Sunday, and through Monday for Cold Bay and vicinity. A blizzard watch was posted for St. Lawrence Island through Monday. Clouds and precipitation in the northeastern quadrant of a storm in the southern Gulf of Alaska remained over the Panhandle on Sunday.
Residents of McGrath and the Kuskowin Valley experienced the "first taste of spring" on Friday as the high temperature reached 37 degrees, for the first above freezing temperature in almost 2 months.
The overnight lowest temperature in the state as of Sunday was 22 degrees below zero at Wainwright. The midafternoon highest temperature was 50 degrees at Metlakatla.
HAWAIIAN WEATHER -- After a somewhat blustery and showery weekend, the ridge of high pressure to the north of the islands was beginning to weaken slightly on Sunday afternoon, accompanied by a weakening of the strong trade winds. As of late Sunday afternoon, the center of the high was situated approximately 600 miles to the north-northwest of Honolulu. The trade showers are expected to be reduced, except for Maui and the Big Island, where they should continue through Monday. By early Sunday morning, Honokaa on the windward slopes of the Big Island had received 5 inches of rain in 24 hours, while other locations on the windward slopes of the Big Island and Maui received more rain. Large ocean swell generated by storms well to the northwest in the North Pacific during late last week propagated toward the islands, reaching them by early Saturday and producing high surf to as high as 18 feet along some of the northwest facing beaches. High surf continued into Sunday evening, with heights expected to remain between 10 and 15 feet through Monday morning. As a result, a high surf advisory was continued for the northwest shores of the islands. Gale warnings were posted for the inter-island channels for winds between 39 and 54 mph, while small craft advisories were continued for state waters.
A FIRST -- Over the weekend, a hot-air balloon with aviators Bertrand Piccard and Brian Jones completed an historic around the world non-stop flight, landing in the desert of southwestern Egypt. They traveled more than 26,00 miles from the Swiss Alps to circumnavigate the globe in 19 days. The balloon was essentially at the mercy of the winds aloft, with some control afforded by changing the balloon's altitude. Travel around the world required locating the upper tropospheric jet streams and attempting to use them to "hitch a ride". Piccard is the grandson of Auguste Piccard, a French balloonist who invented a pressurized balloon gondola and who in 1931 was the first to reach the stratosphere in a balloon on an ascent to at least 50,000 feet.
REPORT FROM THE FIELD - The following was a personal observation made during twilight on Friday night in rural south central Wisconsin near Madison. Clear skies were the result of being near the center of a high pressure cell. In addition to the close apparent alignment of Saturn and Venus, a thin crescent moon was observed nearby. Since new moon had occurred last Wednesday, the moon was located between the earth and the sun, resulting in only a small portion of the lunar disk that was brightly illuminated. The rest of the lunar disk facing earth was faintly visible, bathed in "earthshine", or diffused light reflected from the earth. For optimal earthshine, especially in the Midwest, several storm systems in the Pacific Ocean should provide sufficient cloud cover to increase the albedo of the sector of the earth-atmosphere system under the moon.
DID YOU NOTICE THE EQUINOX? -- The daylength has been getting longer, and astronomical spring started on Saturday evening with the vernal equinox, as discussed on Monday's Supplemental Information.
BECOMING AWARE -- During this coming week of 21-27 March, New York (named "Hazards Awareness"), Pennsylvania (Weather Emergency), Vermont (Hazardous Weather) and Nebraska have their Severe/hazardous Weather Awareness Week. . On Tuesday, 23 March, Virginia, Maryland and the District of Columbia will observe Tornado Preparedness Day. These weeks are usually scheduled before the onset of the severe weather season in that particular state. If you live in any of these states, you should take time to become familiar with the various public affairs announcements issued by your local National Weather Service Office. In upcoming weeks, other states will observe Severe Weather Awareness weeks.
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.