WEATHER OVER THE WEEKEND -- A storm system moved into the Pacific Northwest on Friday. The cold front associated with this system traveled to the south and east, crossing the northern Rockies and into the Great Basin by Saturday morning. The northern sections of the cold front moved steadily eastward on Sunday. Ahead of the front southerly winds were the rule. As a result, unseasonably mild conditions were found across the Plains and western Great Lakes over the weekend. On Friday, Alpena, MI had a record high temperature of 78 degrees. Bismarck, ND had a low temperature on Saturday of 49 degrees, which was a record high minimum temperature for the date. Rapid City, SD had a record-tying 81 degrees on Saturday. In the warm air ahead of the cold front, high temperatures Sunday afternoon ranged between 10 and 20 degrees above the average high for the day across the Northern Plains and western Great Lakes southward to the Ohio and lower Mississippi Valleys.
A cold pool of air was found behind the cold front. Afternoon highs on Sunday afternoon across the Rockies and portions of the Intermountain West were below average. The southern portion of the front pushed southeastward during the weekend, helping initiate wet weather over the Southwest. Record rainfall totals were reported on Sunday at Tucson with 1.19 inches and at Douglas with 0.71 inches. the rain total at Tucson made Sunday the eleventh wettest October day on record. Across southern Arizona, highs on Sunday were as much as 20 degrees below the average highs as a result of the clouds and the rain. Record low high temperatures were reported on Sunday at Douglas (59 degrees) and Organ Pipe Cactus National Monument (63 degrees). On Sunday morning, Eureka, CA had a record-tying low temperature of 37 degrees.
Rain and thunderstorms spread across the southern Plains. On Friday afternoon a weak tornado or "landspout" was reported near Dodge City, KS. Two reports of tornadoes were made on Saturday from the Red River Valley of southwestern Oklahoma. Large hail fell in southeastern New Mexico and in southern Utah on Saturday, and wind damage from a thunderstorm was reported in Yuma, AZ. Thunderstorms spawned several tornadoes that were spotted in central Oklahoma near Oklahoma City on Sunday afternoon and early evening. A funnel cloud was also reported near San Marcos, TX. The thunderstorms also produced pea to marble sized hail near Austin, TX and in Oklahoma. Winds reached 60 mph near Oklahoma City and Lawton, OK. Oklahoma City had record rainfall on Sunday with 3.90 inches, more than doubling the previous daily record.
Dry weather continued across the Southeast over the weekend as high pressure remained over the region. As of Sunday morning, Greensboro, NC had 26 consecutive days without measurable precipitation (at least 0.01 inches), establishing a new record for that city.
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.
Thunderstorms continued to develop across the southern Plains late Sunday night. Most of the thunderstorms stretched northward from the Red River Valley in southern Oklahoma into eastern Kansas, well ahead of a cold front that stretched across the Plains. The thunderstorms developed in the warm, moist and unstable air that lay across the southern Plains and lower Mississippi Valley. With southerly winds, late night temperatures remained in the 70s across north Texas and the 60s as far north as central Iowa, while dewpoints were in the 60s from the Gulf to northern Missouri. Earlier in the evening, severe weather to include tornadoes, large hail and high winds moved across Oklahoma in association with some of the thunderstorms that turned severe. A slight risk of severe thunderstorms continues into early Monday morning across Oklahoma. In addition to the severe weather, heavy rainfall accompanied these thunderstorms. As a result of the heavy rains, flash flood watches were in effect over much of central and south central Oklahoma, extending across the Red River into north Texas. Farther south in the warm air, flash flood watches were also in effect for the region around Houston in southeast Texas.
A cold front ran from a low pressure system centered over northern Hudson Bay across Minnesota, South Dakota, Nebraska and Kansas before curving westward to a weak low pressure center over southern Colorado. The front continued westward and then southwestward as a stationary front. Colder air was found to the north and west of the front. Snow was falling across the higher elevations of the southern Rockies on Sunday night. Snow advisories were in effect for the western San Juan Mountains of southwestern Colorado for between four and ten inches of snow and for the Sangre de Cristo Mountains of southern Colorado, where four to eight inches of snow are possible for elevations above 9500 feet. A winter storm warning was issued for heavy snow in the eastern San Juan Mountains above 9500 feet, with more than 8 inches of snow expected by Monday afternoon in the vicinity of Wolf Creek Pass. The cold front is expected to travel eastward, with the northern portion of the front located over northwest Wisconsin by Monday evening and the southern sections of the front situated over central Kansas.
Heavy rains continued across southern California, Arizona and New Mexico on Sunday night in association with a large low pressure system situated over the northern Gulf of California in northwest Mexico. Tropical moisture continued to feed into this system from the south. Showers and thunderstorms were expected to continue into Monday. Because of the heavy rains across the region for several days a variety of flash flood watches and small stream flood advisories were posted across Arizona.
Northwesterly winds to the northwest of the surface low helped generate large surf on the west-facing beaches of southern and central California, as seas reached heights of 13 feet off Point Conception. Wind advisories were also in effect for southern California, particularly in the mountains surrounding the Los Angeles Basin.
Most of the precipitation is expected to shift northward and eastward across northern sections of Arizona and New Mexico on Monday. The low is expected to move northward into the lower Colorado Valley. Precipitation amounts on Monday could range from 0.25 inches over much of the Southwest to more than 1.5 inches in east central New Mexico.
A large high pressure situated over the Upper St. Lawrence River Valley on Sunday night was spreading cool Canadian air southward across the Northeast. Afternoon high temperatures across the Northeast were seasonal. The southern periphery of this cool air mass was a cold front that trailed southwestward across the North Atlantic from near Newfoundland before crossing into North Carolina. A stationary front that stretched from western North Carolina northwestward to the mid-Mississippi Valley separated the cool air mass from warmer and more humid air across the lower Mississippi Valley.
The high is expected to move slowly east-southeastward, becoming centered over northern New Hampshire by Monday morning and over Massachusetts Bay by evening. With relatively clear skies, weak winds and a cool air mass, nighttime temperatures are expected to fall to the low 30s as a result of enhanced radiational cooling. Consequently, frost advisories were issued for southern New Jersey, eastern Pennsylvania and the northern portions of the Del-Mar-Va Peninsula.
A frontal system is expected to approach the Pacific Northwest late on Monday afternoon, resulting in clouds and possible precipitation across Washington's Olympic Peninsula by late evening.
Sunday's landing of the Space Shuttle Discovery at the Kennedy Space Center at Cape Canaveral, FL was postponed because of high crosswinds that gusted to 22 mph across the runway. Another attempt will be made on Monday. However, possible strong winds in Florida and clouds at the alternate landing site at Edwards Air Force Base in southern California could also pose a problem, forcing the Shuttle to remain in orbit.
TEMPERATURE EXTREMES ACROSS THE LOWER 48 -- On Sunday, the lowest temperature reported in the continental U.S. was 12 degrees at Elko, NV, while Sunday's highest temperature was 90 degrees at Cottula, TX.
ALASKAN WEATHER -- A strong storm system located south of the Kenai Peninsula was moving toward mainland Alaska on Sunday afternoon, with a central pressure of 984 mb. A stationary front extended northeastward from near the Kenai Peninsula across the Copper River Basin into the Yukon Territory. Clouds were found across southern Alaska from the eastern Aleutians eastward across south central Alaska. A mixture of rain and snow fell at Cold Bay, while rain fell at Sand Point earlier Sunday. Most of the precipitation was located across southeast Alaska. Ketchikan had 2.63 inches in the 24 hours ending on Sunday morning, while Annette Island had 2.15 inches. Cold Bay and Dutch Harbor also experienced strong northwesterly winds with gusts to 46 mph as a tight pressure gradient developed between a ridge of high pressure over the central Aleutians and the storm system over the western Gulf of Alaska.
An occluded front associated with another low pressure system centered near the Kamchatka Peninsula stretched across the western Aleutians. Strong southerly and southeasterly winds were also found across the western end of the Aleutian chain as a result of the tight pressure gradient that developed between the ridge of high pressure over the eastern Aleutians and the low pressure center near Kamchatka.
High pressure was located over the Arctic Ocean. Onshore flow produced clouds along the North Slope, and snow fell on Sunday afternoon at Barrow. Partly cloudy skies were found across northwest Alaska, the Seward Peninsula and the Yukon-Kuskokwim Delta.
The lowest overnight temperature in Alaska as of Sunday morning was 13 degrees below zero at Unalakleet, and the midafternoon highest statewide temperature was 57 degrees at Ketchikan.
HAWAIIAN WEATHER -- Relatively routine trade wind weather was found across Hawaii on Sunday as a subtropical high pressure system was moving eastward across the North Pacific Ocean about 1400 miles north of Honolulu. However, showers upwind of the islands on Sunday afternoon were expected along the windward slopes of the Big Island and Maui by Sunday night. The northeast trade winds were expected to continue having wind speeds between 10 to 25 mph as the high passes to the north of the islands. High surf advisories were in effect for the north and west facing shores of all the islands. Surf running between 12 to 18 feet are expected along the north shores of Kauai and Oahu, and from 8 to 12 feet along the west facing shores.
EYE ON THE TROPICS -- Tropical Depression 18, which formed Thursday in the western North Atlantic, intensified to become Tropical Storm Nadine on Friday. However, by Saturday night Tropical Storm Nadine had moved rapidly to the North Atlantic and had lost its tropical characteristics.
WINTER AWARENESS -- Several states are observing their Winter Weather Awareness Week during this upcoming week (23-27 October) to include Nevada (called Winter Weather and Flood Awareness Week) and South Dakota. 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