DATASTREME DAILY SUMMARY

Wednesday, 11 October 2000


00Z Weather Systems


THE BIG CHILL CONTINUES -- The arctic high pressure continued to keep much of the nation east of the Rockies unseasonably cold on Tuesday. By late evening, the high was centered over the confluence of the Ohio and Mississippi Rivers. Numerous record low temperatures were reported from the Plains to the East Coast, with the largest concentration across the Southeast. The record low temperature of 31 degrees at Charlotte, NC also marked the earliest date of a freezing temperature.

Much of the nation experienced below average high temperatures on Tuesday. Afternoon highs across the Southeast, the South Central and West Coast were between 10 to 15 degrees below the long term average highs for the date. South Texas and the Rio Grande Valley experienced highs that were on the order of 30 degrees below the average highs. Numerous stations across Texas and other southern Plains states established new daily low maximum records, eclipsing long standing previous records by as much as 10 degrees. Only the northern Plains and the northern Rockies could be considered relatively warm as high temperatures there ranged from 10 to 15 degrees above the average highs for the date.

This high pressure cell is expected to drift slowly to the east on Wednesday, reaching south central Kentucky by Wednesday evening. A variety of freeze warnings and frost advisories were posted from Indiana southward into Georgia and eastward to the coastal Carolinas.

WINTRY CONDITIONS IN THE NORTHEAST -- A storm system moving across the Maritime Provinces contributed to the precipitation that fell across New England on Tuesday. As much as 10 inches of snow fell on the higher terrain of northern Maine. This storm system was centered near the mouth of the St. Lawrence River late Tuesday night. Chilly north to northwesterly winds continued across the Northeast in response to the tight pressure gradient surrounding the low pressure center. Light and widely scattered precipitation continued over northern New England and Upstate New York.

Some movement of the storm system to the northeast is expected on Wednesday, with a dwindling of the precipitation over New England.

UNSETTLED WEATHER CONTINUES ACROSS THE WEST -- A broad, complex region of low pressure with several low pressure centers and accompanying fronts dominated the weather across the Intermountain West on Tuesday night. Widespread clouds that covered much of the West were rotating in a counterclockwise manner around a cold pool of air that extended upward through most of the troposphere (lowest 30,000 feet) over Idaho. Scattered precipitation was falling across the Western States on Tuesday night, with the heaviest found across eastern Washington and Oregon, Montana, southern Idaho, Utah, California and southern sections of Arizona and New Mexico. Earlier, snow fell on the central and northern Sierras at elevations above 7000 feet. At the surface, southerly winds to the east of the cold front that stretched southward from the Snake Valley of Idaho brought relatively mild air northward across eastern Utah and western Colorado, while westerly winds contributed to the cooler air across Nevada.

By Wednesday morning the cold front and one of the associated lows is expected to move eastward across the Great Basin, reaching the western slopes of the Rockies. The front is expected to reach the eastern slopes of the northern Rockies by evening. Snow advisories were in effect for the mountains of southwest Colorado, most of Utah and southeast Idaho.

YESTERDAY'S TEMPERATURE EXTREMES ACROSS THE CONTINENTAL US --Tuesday morning's lowest temperature was 13 degrees at Jeffrey City, WY, while the highest temperature on Tuesday was 88 degrees at Douglas, AZ.

ALASKAN WEATHER -- Clouds covered almost all of Alaska on Tuesday. A large storm sytem over the North Pacific generated precipitation and gusty winds across the southern part of the state. This storm consisted of a low pressure center located south of the Alaska Peninsula and an occluded front that extended eastward along the North Gulf coast. A variety of precipitation types were reported along the coast, to include snow and a mixture of rain and snow. A tight pressure gradient between higher pressure elsewhere and the low pressure center produced strong winds, especially to the northwest of the system. Peak wind gusts approaching 50 mph were reported at Dutch Harbor, while Cold Bay, Dillingham, Kodiak and Homer had gusts to 40 mph. A front over the Arctic Ocean contributed to windy conditions across the North Slope. Subzero wind-chill equivalent temperatures were reported at Barrow, Wainwright and Delta Junction. At Deadhorse, the combination of single digit temperatures with 10 to 15 mph winds produced a wind-chill equivalent temperature of 22 degrees below zero.

The state's lowest overnight temperature on Tuesday morning was 6 degrees below zero at Arctic Village. The highest temperature by mid afternoon of Tuesday was 53 degrees at Ketchikan and Shemya.

HAWAIIAN WEATHER -- Northeasterly trade winds remained over the islands on Tuesday as a ridge of high pressure was located to the north and northeast of Hawaii. A band of showers passed across the islands on Tuesday from a region to the north. A tropical disturbance moving westward should pass to the south of the Big Island with little anticipated disruption in weather.

Small craft advisories were continued across state waters.

MONITORING THE DROUGHT -- Read the optional Wednesday Supplemental Information concerning assessing drought conditions.

REPORTS FROM THE FIELD -- Staff members Bob Weinbeck, Joe Moran and Missy Ficek at DataStreme Central in Washington, DC reported a 3 to 5 minute burst of snowshowers on Monday afternoon. Interestingly, the surface temperatures reported at nearby National Airport were in the low 40s.

Karyl Rosenberg, a DataStreme participant from Thiensville, WI, reported that over the weekend she had the opportunity to see the lake-effect snow produced by Lake Superior. She was impressed by the "very striking sights" provided by the snowflakes falling on the foliage that still had its fall colors in the vicinity of the northern Wisconsin community of Minocqua.

Faye McCollum, LIT Leader and AERA from Columbus, GA reported on the continued drought conditions across southern Georgia. Apparently the welcome September rains that accompanied Tropical Storm Helene did little to help the agricultural interests in the state


HISTORICAL WEATHER EVENTS - 11 October

From the files of the Aviation Weather Center, Kansas City, MO and Intellicast


Return to DataStreme Homepage

URL Address: datastreme/learn/w_sum.html
Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2000, The American Meteorological Society.