The following highlights of the national weather have been extracted from the surface weather map for Thursday night:
WET WEATHER SPREADS INTO THE MIDWEST -- A large area of rain and embedded thunderstorms continued to move northeastward into the Ohio Valley and southern Great Lakes on Thursday. This precipitation was associated with an occluding storm system located near the confluence of the Ohio and Mississippi Rivers on Thursday evening. An occluded front was just beginning to form and extend eastward from the low pressure center. A warm front stretched northeastward along the Ohio Valley before crossing the Appalachians and the Middle Atlantic States. A cold front trailed southward across the Tennessee Valley to the Gulf Coast near Mobile Bay.
A broad southerly wind flow brought Gulf moisture northward. Abundant moisture was associated with this storm system as evident by the heavy rains that had fallen across the lower Mississippi Valley on Wednesday and Thursday. Precipitation records were set once again on Thursday in Tennessee at Jackson (3.48 inches), Memphis (2.49 inches), Dyersburg (2.30 inches) and Nashville (1.41 inches); in Mississippi at Tupelo (3.76 inches) and in Arkansas at Jonesboro (1.53 inches). As a result, some areas in the Memphis, TN metropolitan area reported storm-total precipitation of more than 8 inches. Numerous buildings and roads were flooded as a result of this excessive rain event. At least one fatality was reported, the result of drowning in a car that was submerged in a drainage ditch in Mississippi.
The low pressure center is expected to continue moving northward on Friday, reaching the vicinity of Chicago, IL by daybreak and to northern Lake Huron by early evening. With the cold front moving more rapidly eastward than the northward movement of the warm front, the occluded front should lengthen to the east, indicating the progression of the system through the occlusion process. Between 0.5 and 1.4 inches of rain are expected to fall in the 24 hours ending on Friday evening over a relatively large area of the Midwest, extending from middle Tennessee north and eastward across the Ohio Valley into the eastern Great Lakes. A winter storm watch was issued for eastern portion of Michigan's Upper Peninsula as freezing rain could develop on Friday morning.
MORE SEVERE WEATHER ACROSS THE SOUTH -- Some of the thunderstorms that developed in the warm sector of the storm system turned severe. A tornado was spotted in central Mississippi to the east of Jackson during the late morning. Strong thunderstorm winds destroyed a mobile home and caused at least one injury to the northeast of Jackson. Trees and outbuildings were also damaged by thunderstorm winds elsewhere in Mississippi and at several locations in Louisiana and Tennessee during the afternoon and evening. Thunderstorms over the Gulf produced a waterspout that was seen from Pass Christian, MS.
ANOTHER WARM DAY IN THE EAST -- Unseasonably mild weather continued across the eastern third of the country on Thursday to the east of the storm system and accompanying fronts in the Mississippi Valley. High temperatures were as much as 15 to 20 degrees above average across the Ohio Valley and Middle Atlantic States. Record high temperatures were either tied or set on Thursday in Georgia at Augusta (81 degrees) and Atlanta (76 degrees); in South Carolina at Florence (80 degrees); in North Carolina at Raleigh-Durham (77 degrees), Charlotte (76 degrees) and Greensboro (75 degrees); in Tennessee at Chattanooga (76 degrees), Knoxville (76 degrees) and Bristol (75 degrees); in Kentucky at London (71 degrees) and in Virginia at Norfolk (77 degrees).
WINTRY WEATHER OVER NEW ENGLAND -- Snow and freezing rain were falling across northern New England to the north of the warm front that stretched eastward from the storm in the Midwest to the Eastern Seaboard. The air was sufficiently cold across northern Maine to support snow. However, at some locations closer to the front, rain was falling through the relatively shallow layer of cold air and freezing.
WINTRY WEATHER IN THE WEST -- A relatively cool pool of air was found across the West. The Pacific storm system that moved on to the West Coast late Wednesday was moving across the Intermountain West spreading widely scattered snow across the mountains. Winter storm warnings and snow advisories were in effect across much of Utah, western Colorado and northwestern New Mexico. More than a foot of snow is expected along the Wasatch Front in Utah, while four to eight inches of snow could fall by morning in some locations in Colorado.
With a fresh snow cover and a relatively cool air mass, Midland, TX had a record low temperature of 11 degrees and a record low high temperature of 36 degrees. Afternoon high temperatures across the southern Plains ranged between 20 to 25 degrees below average. Because of the clouds record low maximum temperatures were reported also reported in east Texas at Longview (36 degrees) and Lufkin (37 degrees).
MORE STORMS APPROACH THE NORTHWEST -- A storm system moved inland late Wednesday night spreading heavy snow across the mountains. Two feet of new snow were reported at Donner Summit near the crest of the central Sierras early Thursday morning. Between 12 and 19 inches of new snow fell across the mountains of Idaho and Montana, while up to 12 inches were reported in northeastern Nevada. Record precipitation was also reported at Pismo Beach, CA (0.90 inches) in association with the cold frontal passage.
The next Pacific storm in the series of storms that have hit the West Coast in the last week was located several hundred miles to the west of Vancouver Island. This low pressure system with accompanying front is expected to reach the coast by Friday morning, spreading precipitation across the Pacific Northwest in advance. Behind that storm, another is forecast to follow by sometime on Saturday. Gale warnings were posted for marine interests northward from Florence, OR, to include the Strait of Juan de Fuca. Heavy surf advisories were in effect along the coast from Florence, OR to Point Piedras Blancas, CA. Between 0.4 and 1.4 inches of liquid equivalent precipitation could fall along the western slopes of the Coast Range, the Olympics and the Cascades during the 24 hours ending on Friday evening.
UPPER AIR -- Both the 500 and 300 mb charts for 00Z Friday have a height trough across the Intermountain West and a ridge of higher heights along the East Coast. The trough reflects the colder air that extends upward through the troposphere over the West, while the ridge is associated with a warmer troposphere over the East. In addition, a depression in the two pressure surfaces is found over the lower Mississippi Valley, corresponding to the surface low pressure system. The cyclonic or counterclockwise circulation feature surrounds a slightly colder pool of air that extends upward from the surface low. A relatively strong band of winds is found to the south and east of the upper level trough.
TEMPERATURE EXTREMES ACROSS THE CONTINENTAL US -- Thursday's lowest temperature was 10 degrees below zero at Alamosa, CO. Thursday's highest temperature was 84 degrees at Sarasota and Winter Haven, FL.
ALASKAN WEATHER -- An arctic air mass associated with weakening high pressure over the Yukon Territory continued to dominate the weather across much of mainland Alaska. Relatively clear skies were found across interior Alaska. Many locations experienced subzero temperatures during the early afternoon, with Northway reporting 29 degrees below. A stationary front marking the southern and western boundaries of this arctic air mass ran from the northern Bering Sea southeastward across Bristol Bay and the Alaska Peninsula, then eastward across the northern Gulf of Alaska before curving southeastward across the eastern Gulf to parallel the coast of the Panhandle and British Columbia. A low pressure area was developing across the central Gulf of Alaska. Clouds were found across south central Alaska and along the Panhandle. Dillingham was the only location in the state that reported snow on Thursday afternoon. Farther west, a developing storm system was moving eastward across the western Bering Sea. A front associated with this storm spread clouds across western Aleutians.
The lowest overnight temperature in Alaska on Thursday morning was 42 degrees below zero at Northway, while the mid-afternoon highest statewide temperature was 39 degrees at Dutch Harbor.
HAWAIIAN WEATHER -- A large subtropical high pressure cell was building to the southwest across the Pacific Ocean toward the islands. As a result, northeast trade winds have returned to the Aloha State after several days of southerly winds. These trade winds had speeds that ranged between 10 to 20 mph. The Kona low that produced the heavy rains across the islands earlier in the week has moved well to the west and most of the clouds have dissipated across the state. With a return of trade winds, isolated trade showers are expected to form on the windward slopes of the islands especially at night and during the early morning.
EYE ON THE TROPICS -- Hurricane Olga began weakening on Thursday and was downgraded to a tropical storm when sustained winds fell below 75 mph. As of late Thursday night, Tropical Storm Olga was moving toward the southwest at 20 mph and was located 455 miles to the south of Bermuda. Maximum sustained surface winds were 50 mph.
SKYWARN RECOGNITION DAY -- The National Weather Service (NWS) and amateur radio groups will conduct the second annual "SkyWarn Recognition Day" across the US commencing later today and running for 24 hours. (The start is at 00Z on Saturday, 1 December 2001, which corresponds to 7 PM EST on Friday evening, 30 November.) Participating NWS offices will commemorate the contributions that amateur radio operators make during threatening weather episodes. During the 24 hours numerous contacts between radio operators will be made on various bands, together with an exchange of weather information. For more information, consult the website http://www.crh.noaa.gov/gld/amateur.htm operated by the NWS Office in Goodland, Kansas.
FULL MOON -- The moon will reach the full moon phase this afternoon at 2049Z (or 3:49 PM EST or 2:49 PM CST, etc.). The full moon of November is often called the "Frosty Moon" or "Beaver Moon".
END OF A SEASON -- Today is the last day of November, marking the end of both meteorological autumn and the official hurricane season in the North Atlantic basin. For more details, please check Friday's optional Supplemental Information.
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, 2001, The American Meteorological Society.