DATASTREME DAILY SUMMARY

Friday, 10 November 2000


00Z Weather Systems


TAKE A MOMENT - Since tomorrow is Veteran's Day, formerly called Armistice Day, take a moment to remember this country's veterans, especially those who never made it home.

SEVERE WEATHER PUMMELS THE OHIO VALLEY -- Severe thunderstorms accompanied by high winds moved through the Ohio Valley and across the Appalachians during Thursday afternoon and evening. These thunderstorms were in association with a storm system that had moved from the lower Mississippi Valley to the Great Lakes on Thursday. As of late evening, 78 reports of high winds were made from Kentucky, southern Indiana, southern Ohio, Tennessee, Virginia and the western Carolinas. In Knoxville, TN the high winds caused a large tree to fall on a pickup truck, killing two children and injuring their father. These winds also felled numerous trees and power lines. A 92 mph wind gust was reported at Bowling Green, KY . Large hail was also reported in suburban Louisville, KY. Earlier in the day, severe thunderstorms produced wind damage in Alabama and northern Georgia, where large hail also fell.

The occluding low pressure center as of late Thursday night was located over western Lake Erie with an occluded front that extended southeastward over Ohio, where a warm front extended eastward across the Appalachians to the Del-Mar-Va Peninsula, while a cold front continued southward along the Appalachians to the Florida Panhandle and out across the Gulf of Mexico. Thunderstorms continued along the cold front, especially across southeastern Ohio, western Pennsylvania and West Virginia. This area was under severe weather watches. Additional thunderstorms were also detected farther south along the cold front, across the Piedmont of the Carolinas. A large precipitation shield also extended around the northern and western sides of the system, from the Middle Atlantic and southern New England westward to the central Great Lakes.

The storm system is expected to continue its occlusion process as the primary low pressure center moves northward into Ontario. A secondary low is forecast to develop near the point of occlusion and move to the lower Delaware Valley Friday morning. By evening, the secondary low is expected to move northeastward offshore of the Middle Atlantic coast, while the primary low dissipates over Ontario. A slight risk of severe thunderstorms continues through Friday morning for a region to the east of the advancing cold front, extending from the eastern lakes southward to the Carolinas. As much as 1.5 inches of rain could fall across New England between Friday and Saturday mornings.

WINTRY WEATHER ACROSS THE WEST -- Essentially all of the nation west of the Mississippi experienced unseasonably cool weather on Thursday as afternoon high temperatures were below the long-term average highs for the date. The largest departures where across Montana, where high temperatures ranged between 25 and 35 degrees below the average. Several locations set daily low maximum temperature records, to include Sioux City, IA (23 degrees), Sioux Falls, SD (23 degrees), Amarillo, TX (34 degrees), Texarkana, AR (45 degrees). Record low temperatures were also set at Sioux City, IA (13 degrees), Amarillo (16 degrees), Liberal, KS (16 degrees), Goodland, KS (16 degrees) and Del Rio, TX (33 degrees).

A large and diffuse region of low pressure situated over the Great Basin on Thursday night was expected to produce heavy snows across much of the Rockies through Saturday morning. One low pressure center located over northwestern Arizona had an accompanying cold front that stretched southwestward into southern California. Another low center was located over the central Sierras. Widely scattered light precipitation was detected across the West.

The low pressure area over northern Arizona is expected to drift eastward on Friday. Precipitation in the form of mountain snow is expected to continue with some significant accumulations. A winter storm warning was in effect through Friday for much of Utah, as 1-2 feet of new snow are expected in the northern Wasatch and the Uinta Mountains, while in the southern mountains, 3 to 6 inches could fall. Snow advisories were posted for portions of northern Arizona, Nevada and Wyoming, where as much as 6 inches are likely by late Friday. A winter storm watch was posted effective Friday and Friday night for Colorado west of the Continental Divide, along with adjacent counties in Utah. As much as a foot of snow was expected, along with southwest winds to as high as 35 mph.

With relatively clear skies across the lower Mississippi Valley and southern Plains associated with cold high pressure, vigorous nighttime cooling should result. Freeze warnings were issued for portions of west Tennessee and northeast Arkansas in the vicinity of Memphis, TN, and the Hill Country of central Texas. Cold air spilling into northern California necessitated frost advisories for the central valleys of that state.

UPPER AIR -- The upper air charts for 00Z on Friday revealed a large height trough over the West Coast. This trough reflects the cold air that continues over the region. A height ridge is found across the East Coast, where relatively warm air was located. As a result, the upper tropospheric flow was from the southwest across much of the nation.

TEMPERATURE EXTREMES ACROSS THE CONTINENTAL US -- Thursday's lowest temperature was 8 degrees below zero at Jordan, MT. Thursday's highest temperature was 86 degrees at Opa Locka, FL.

ALASKAN WEATHER -- High pressure located over northwest Canada maintained a relatively cold air mass over eastern Alaska. The western boundary of this air mass was a front that extended southeastward from the Lisburne Peninsula in northwest Alaska to the Wrangell Mountains in southeast Alaska. Relatively warm air was found to the south and west of this front, as southeasterly winds brought relatively mild air northward. As a result of this warm air advection, rain fell at Nome, a relatively unusual event. An occluded front associated with a major storm system in the western Bering Sea curved southeastward across the central Aleutians. Farther east, a weak storm system was located just south of the Alaska Peninsula. These systems produced clouds and rain across most of the Aleutians, the Alaska Peninsula and the region surrounding Bristol Bay. Weak high pressure was located across the eastern Gulf of Alaska, southeast Alaska and the Panhandle. Easterly winds were found across the North Slope, causing blowing snow at Barrow and Deadhorse. These strong winds also caused wind-chill equivalent temperatures to fall to 55 degrees below zero at Barrow. Winds gusted to as high as 46 mph at Barter Island on Thursday morning.

The lowest overnight temperature in Alaska on Thursday morning was 27 degrees below zero at Arctic Village, while the mid-afternoon highest statewide temperature was 50 degrees at Dutch Harbor.

HAWAIIAN WEATHER -- Typical trade wind weather continued across the 50th State on Thursday as a result of high pressure to the north of the islands. East to northeast trade winds had speeds ranging from 10 to 25 mph. A series of high pressure systems are expected to move eastward across the North Pacific over the weekend, maintaining the pressure gradient across the islands. As a result, easterly trade winds will be maintained with speeds ranging from 10 to 15 mph. Some brief trade showers could fall on the windward slopes of the mountains, especially at night and early mornings.

A SOMBER ANNIVERSARY -- Today is the 25th anniversary of the sinking of the Great Lakes ore carrier, Edmund Fitzgerald, during a powerful storm on Lake Superior. The National Weather Service Forecast Office at Marquette, MI has a web page commemorating the sinking and describing the advances in marine weather forecasting over the last quarter century.

FULL MOON -- The moon will reach the full moon phase late tomorrow afternoon at 2115 Z (or 4:15 PM EST or 3:15 PM CST). The full moon of November is often called the "Frosty Moon" or "Beaver Moon".


HISTORICAL WEATHER EVENTS - 10 November

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

11 November

12 November


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Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2000, The American Meteorological Society.