A "TIMELY" REMINDER -- Over the weekend most of the nation turned the clocks back one hour from Daylight Saving Time to Standard Time. For those who may have missed the excerpts from last Friday's summary discussing the fall time change, please check Monday's optional Supplemental Information .
WEATHER OVER THE WEEKEND -- Following an exceptionally active weather week, most of the country experienced relatively tranquil weather over the weekend, with no severe weather and relatively little precipitation. However, unseasonably cold air moved into the East and South while the much of the West remained unseasonably warm.
The storm system that produced the severe weather across the nation's midsection along with the early-season snows in the northern Plains moved northeastward into Canada on Friday from its position over Lake Superior on Thursday night. By Friday evening the low was located over central Quebec and the strong northwesterly winds that had plagued the western Great Lakes on Thursday had begun to weaken as the region of tightest pressure gradient moved toward the northeast. Cold air continued to pour into the eastern half of the country behind the departed storm system that had moved into eastern Canada. Lake-effect snow continued to fall across Michigan's Upper Peninsula on Friday and into Saturday as cold northwesterly winds continued to move across the relatively warm waters of Lake Superior. New daily snowfall records were established on Friday and Saturday at Marquette with 4.5 and 2.1 inches, respectively. The 0.41 inches of liquid equivalent precipitation (rain and melted snow) that fell on Friday also set a 24-hour precipitation record for the date at Marquette.
The first wave of cold air that spread across the East and Southeast on Friday had followed behind the cold front responsible for the midweek severe weather episode. The second wave of cold air that swept across the northern Plains and Great Lakes States on Friday was associated with high pressure that had been centered over Saskatchewan on Thursday night. New record low temperatures were set on Friday morning at Sioux Falls, SD (14 degrees) and at Casper, WY (15 degrees). Afternoon high temperatures were 10 to 15 degrees below late-October average highs from the Dakotas eastward to New York State and southward to the Ohio Valley. The afternoon high temperature in Rochester, MN was only 36 degrees, a record-tying low maximum temperature. By Friday night this cold high pressure cell had moved into the Dakotas.
On Saturday, the cold air spread southeastward as the center of the high moved into Missouri by morning and to the confluence of the Ohio and Mississippi Rivers near Cairo, IL by evening. Record low temperatures were set on Saturday morning at St. Joseph, MO (19 degrees) and Jackson, TN (28 degrees). Most of the country to the east of the Mississippi River experienced afternoon high temperatures that were below average. The largest temperature anomalies (departures between the actual and average highs) were found across the Appalachians and the Cumberland Plateau, where highs were on the order of 20 degrees below average. Binghamton, NY 39 degrees for tying a low high temperature record.
By Sunday morning a sprawling high pressure system was centered over the Ohio Valley, dominating the weather across the eastern half of the country. Record low temperatures were either tied or set on Sunday morning in Alabama at Huntsville (29 degrees), in Georgia at Athens (27 degrees) and Macon (27 degrees) in North Carolina at Charlotte (26 degrees) and in South Carolina at Greenville-Spartanburg (29 degrees) North Myrtle Beach (34 degrees). Sunday afternoon high temperatures ranged from 10 to 15 degrees below average across the Southeast and along the Eastern Seaboard.
High pressure located over the Four Corners region maintained relatively warm and tranquil weather across the West through the first part of the weekend. Friday afternoon high temperatures from the Continental Divide to the West Coast were all above average, with the greatest departures being on the order of 15 degrees above average across southern Arizona and portions of Nevada and Idaho. Record high temperatures were either tied or set on Friday in Arizona at Coolidge (100 degrees), Organ Pipe Cactus National Monument (98 degrees), Phoenix (98 degrees), Tucson (96 degrees), Superior (92 degrees) Douglas (89 degrees), Cottonwood-Tuzigoot National Monument (89 degrees) and Show Low (77 degrees), and in California at Cuyama (90 degrees). The warm spell continued on Saturday with warm air also spreading into the western Plains as the cold high pressure cell over the Midwest moved southeastward, thereby setting up a broad southerly flow of air that brought warm air northward. As a result, much of the western Plains, the Rockies and the Intermountain West experienced some warming as afternoon highs ranged between 15 and 20 degrees above the average highs for the last week of October. Record high temperatures were either tied or set in Arizona at Coolidge (99 degrees), Phoenix (98 degrees), Casa Grande (98 degrees), Carefree (92 degrees), Winslow (83 degrees) and Show Low (77 degrees); in Montana at Glasgow (78 degrees), Helena (76 degrees), Havre (76 degrees) and Bozeman (72 degrees); and in Wyoming at Worland (76 degrees). On both Friday and Saturday the high temperature at Phoenix was also the highest temperature for so late in the season. Sunday afternoon highs across the central Plains and central Rockies were between 15 to 25 degrees above the average high for this time of the year. Record high temperatures were either set or tied in Nebraska at North Platte (86 degrees), in Kansas at Garden City (83 degrees) and Russell (78 degrees), in Colorado at Craig (70 degrees), in Wyoming at Rawlins (68 degrees) and in Utah at Moab (84 degrees), Hanksville (83 degrees), Escalante (76 degrees), and Orem (75 degrees).
A storm system approached the Pacific Northwest early Friday, as a warm front moved across Washington's Olympic Peninsula on Friday morning, followed by a cold front that reached western Washington by evening. This cold front continued moving into interior sections of the Northwest on Saturday, cross the mountains of northwest Montana by Saturday evening, while southern sections of the cold front had pushed southward into northern California. Some light precipitation fell across the Northwest behind the cold front. By Sunday morning northern sections of the cold front had moved across Montana and into the western Dakotas, while the southern portions of the front had stalled across central Idaho, southern Oregon and northern California. Widely scattered precipitation continued to fall across the mountains of the Northwest. Cold air was moving into the region in association with high pressure over southern British Columbia, with the area around Puget Sound experiencing Saturday high temperatures that were on the order of 10 degrees below average. Seattle had a high temperature of only 45 degrees, which tied a low maximum temperature record for the date. As much as 2 to 4 inches of snow fell across central Montana by late Sunday afternoon.
WEATHER FOR THE START OF THE NEW WEEK -- The following highlights of the national weather have been extracted from the surface weather map for late Sunday night:
A large and elongated ridge of high pressure stretched along the Eastern Seaboard from New England south to the Carolinas. Skies were relatively cloud-free and nearly calm wind conditions were the rule under this high pressure system. Dewpoints were also relatively low southward to the Gulf of Mexico. These conditions permit enhanced nighttime radiational cooling. As a result, freeze warnings were posted across all but the southern third of Georgia, and all but the coastal counties in North and South Carolina. Frost advisories were also in effect in the Baltimore and Washington, DC metropolitan areas in Maryland and northern Virginia. This ridge of high pressure is expected to remain anchored across the Southeast and Middle Atlantic States on Monday.
Farther west, the southwesterly winds circulating around the high pressure ridge were keeping nighttime temperatures reasonably high across the southern Plains, the Mississippi Valley and the western Great Lakes. For example, the temperature at Green Bay, WI at 10 PM CST was higher than at Atlanta, GA.
A cold front was moving eastward and southward across the northern Great Lakes, the Upper Mississippi Valley and the northern Plains. This front trailed southward from a storm system over northern Hudson Bay. Northerly surface winds were found behind the cold front, circulating around high pressure along the US-Canadian border. The western end of the cold front became a stationary front that stretched across the northern Rockies and Great Basin into northern California. Some low altitude rainshowers and mountain snow were falling across North Dakota, Montana, Idaho, Oregon, northern Nevada and northern California. Northern portions of the cold front are expected to move eastward across the Great Lakes on Monday, reaching Upstate New York by evening. At that time southern sections of the cold front are forecast to reach the Oklahoma and Texas Panhandles. High pressure is expected to move eastward into southwest Ontario. Some light precipitation, with 24 hour totals of less than 0.10 inches, are expected across the Midwest and into the central Plains.
Farther west, welcome precipitation is expected from Montana westward across Idaho, Oregon and northern California. Amounts should range from near 0.3 inches in the interior to as much as 0.9 inches along the northern California coast near Cape Mendocino. A winter storm watch was posted for Monday night and Tuesday along the west slopes of the southern Cascades and Sierras in California. Initially, the snow line is expected to be above 8000 feet, but later the snow line is forecast to drop to 6000 feet. Accumulations of at least 6 inches of snow are likely by Tuesday morning.
TEMPERATURE EXTREMES ACROSS THE LOWER 48 -- On Sunday, the lowest temperature reported in the continental U.S. was 17 degrees at Bondurant, WY, while Sunday's highest temperature was 94 degrees at Death Valley, CA.
ALASKAN WEATHER -- High pressure located over the Canadian Archipelago to the northeast of Alaska kept much of Alaska relatively dry and cold late Sunday afternoon. Light snow and fog were reported along the Arctic Coast. The arctic air mass extended southward as far as a stationary front that was found stretched along the Alaska Peninsula eastward along the north Gulf Coast to southeast Alaska and then into the southern Yukon Territory. A weak trough line extended northward across south central Alaska and into the interior portions of the state from a storm system in the Gulf of Alaska. An occluded front curved eastward and then southward along the Panhandle before becoming a cold front near the Queen Charlotte Islands. Several areas of light rain and snow were reported along the coastal stations around Prince William Sound, across the Southeast and through the Panhandle. Farther west, a small storm system was moving along the central Aleutians.
The lowest overnight temperature in Alaska as of Sunday was 22 degrees below zero at Anaktuvuk Pass and the midafternoon highest statewide temperature was 50 degrees at Adak.
HAWAIIAN WEATHER -- A large subtropical high pressure located to the north-northwest of Hawaii produced gusty northeasterly trade winds across the islands on Sunday afternoon. Skies were relatively cloud-free across most of the islands with the exception of the windward slopes of the Big Island, where clouds were found. The relatively clear skies on Sunday stood in contrast to Saturday when a shear line, representing remnants of a former midlatitude cold front moved across the Aloha State bringing clouds and showers. The shear line was located to the east of the Big Island on Sunday afternoon. Relatively pleasant trade weather should prevail for the early part of the week, with trade winds becoming more easterly as the high pressure cell moves to the north and then northeast of the islands. High surf advisories were in effect for all north and east facing shores of the islands. A small craft advisory was also posted for state waters.
EYE ON THE TROPICS -- The fourteenth tropical depression of the season developed in the eastern North Atlantic basin during the midday on Saturday. As of late Sunday night Tropical Depression 14 was moving westward at 10 mph approximately 1080 miles southwest of the Azores. Maximum sustained surface winds were 35 mph.
WINTER AWARENESS -- Several states are observing their Winter Weather Awareness Week during this upcoming week (29 October-2 November) to include Iowa and Nebraska. Residents of these states should become aware of the hazards associated with winter weather and review the safety oriented materials prepared by their local National Weather Service Offices.
From the files of the Aviation Weather Center, Kansas City, MO and Intellicast