Friday Daily Weather Summary

ONLINE DAILY WEATHER SUMMARY

Friday, 7 May 1999

AN ADDITIONAL DAY OF SEVERE WEATHER
WARM WEATHER IN THE EAST
COOL WEATHER ACROSS THE WEST
UPPER AIR
YESTERDAY'S TEMPERATURE EXTREMES IN THE LOWER 48
ALASKAN WEATHER
HAWAIIAN WEATHER
REPORTS FROM THE FIELD
A REMINDER
A TIME OUT
HISTORICAL WEATHER EVENTS

AN ADDITIONAL DAY OF SEVERE WEATHER -- Thunderstorms moved across the Southeast on Thursday, producing large hail, high winds and several tornadoes, continuing the activity that started on Monday in the southern Plains with killer tornadoes. As with much of the severe weather for the recent days, Thursday's severe weather activity was associated with the same large, slow moving storm system. This storm system consisted of an occluding low pressure system that was located over northwest Wisconsin on Thursday night. An occluded front curved across the Great Lakes, reaching a point of occlusion of northeast Ohio, where a warm front stretched southeastward across the Middle Atlantic states, while the cold front continued southwestward to the Gulf Coast. Most of the severe thunderstorm activity that occurred from late Wednesday night through Thursday developed along or ahead of this cold front. As of late Thursday night, strong to severe thunderstorms were detected across south central Georgia, southern Alabama, the Florida Panhandle, adjacent waters of the Gulf of Mexico and portions of the Florida peninsula. At least one tornado was detected by Doppler radar moving across southern Georgia.

On Wednesday night, a tornado killed three people as it tore through Linden, TN a town approximately 70 miles southwest of Nashville. Another fatality caused by wind damage occurred near Jackson, TN. More than 50 weather-related injuries were sustained across Tennessee. By Thursday morning, the thunderstorms moved through northern Georgia and into the Carolinas, accompanied by large hail and damaging winds. Approximately 10,000 customers were without power in the Atlanta, GA area. A tornado was detected by Doppler radar to the northeast of Atlanta, while a tornado was also spotted north of Asheville, NC. Thunderstorm-generated winds caused the roof of a warehouse near Camden, SC to collapse and injure 12 people inside. At least one additional wind-related injury was reported in South Carolina. Heavy rain caused flooding in Alabama.

Not all the severe weather occurred in the Southeast. A tornado was spotted by eyewitnesses east of Flint, MI. In addition to the severe weather activity associated with tornadoes, high non-thunderstorm winds associated with the pressure gradient surrounding the storm caused wind damage on early Thursday morning in southern Indian and during the afternoon across northern Ohio.

High non-thunderstorm winds were found to the west of the low pressure system, where the pressure gradient was relatively strong. On Thursday morning, winds gusted to 68 mph at the Rapid City (SD) Regional Airport, a record wind gust for the month of May.

This storm system is expected to wobble slightly, with the primary low over Wisconsin beginning to dissipate and move northwestward by Friday morning. The frontal system is expected to move eastward, with the cold front along the Appalachians.

WARM WEATHER IN THE EAST -- To the east of the front, record high temperatures were set Thursday afternoon at Caribou, ME (81 degrees), Erie, PA (84 degrees) and Orlando, FL (94 degrees).

COOL WEATHER ACROSS THE WEST -- Another surge of unseasonably cold weather was beginning to move into the Pacific Northwest on Thursday night behind a cold front. Rain and high elevation show were falling across western Washington State and Oregon. Snow advisories were posted for the Olympics and the Cascades of Washington State. The cold front was expected to continue its movement eastward, reaching the Idaho Panhandle by Friday morning. Snow is expected over northeast Washington, northern Idaho, and northwest Montana.

High pressure across the central Rockies associated with a relatively dry air mass aided in overnight cooling. Record low temperatures were set on Thursday morning at Abilene, TX (41 degrees) and Grand Junction, CO (30 degrees). This high pressure should remain over the Great Basin through Friday morning.

UPPER AIR --The 500 and 300 mb constant pressure charts for 00Z Friday show that the occluding storm system in the upper Midwest is "vertically stacked". Specifically, the upper level circulation regime is located essentially over the surface low pressure center. The two pressure charts show closed height contours that isolate the regions of lowest height for the given pressure surface, being centered over Wisconsin. Typically, when a storm system occludes, the system becomes vertically stacked with concentric height contours. Earlier in the life cycle of the storm, the axis of the storm bent back with height toward cold air, meaning that the 500 mb trough would be displaced into the cold air from the position of the surface low, with the 300 mb trough displaced by an even large distance.

YESTERDAY'S TEMPERATURE EXTREMES IN THE LOWER 48 -- The lowest temperature on Thursday was 15 degrees at West Yellowstone, WY, while the day's high was 98 degrees at Thermal, CA.

ALASKAN WEATHER -- A large storm system located over the Gulf of Alaska spread clouds across much of the state on Thursday. The low pressure center was near the coast of the Panhandle with an occluded front that spiraled out from the system's center to parallel the Coast Mountains of British Columbia. Rain fell along the Panhandle, with the most falling at Annette. A mixture of rain and snow fell at Anchorage. A ridge of high pressure was located over the Arctic Ocean and another over the western Bering Sea. As a result, partly to sunny skies could be found across the western interior and locations north of the Brooks Range.

The lowest overnight temperature across the state as of Thursday was 3 degrees above zero at Shishmaref. The highest midafternoon temperature was 56 degrees at Cordova.

HAWAIIAN WEATHER -- Easterly trade winds returned to the islands on Thursday as the ridge of high pressure that had been close to the islands shifted to the northeast. The winds also strengthened as the intensity of a high pressure ridge to the northeast of the islands increased. Showers are expected on the windward slopes of the islands on Friday.

A REMINDER -- Sunday is Mother's Day. Take at least a moment to thank your Mom!

A TIME OUT -- Today's Daily Weather Summary discussion is the final one for the spring 1999 course. Starting Monday, 10 May and running through the summer, the Online Weather Daily Summary will contain only the selected Historical Weather Events for that day. Current weather data will be available on the homepage as usual. If you are looking for an alternative description of daily weather, you could try:

http://www.usatoday.com/weather/wlead.htm

Have a happy summer and best wishes in your future endeavors!

HISTORICAL WEATHER EVENTS - 7 May

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

...1840...A powerful tornado wrecked many boats at the Natchez Landing in Mississippi, then plowed through the city on the bluff. The tornado killed 317 persons, and caused a million dollars damage. The force of the storm caused houses to burst open. The tornado was the most deadly and destructive in early American history. (David Ludlum)
...1927...Two massive F5 tornadoes combined for a 95 mile path of destruction through Comanche, Barber, Kingman, Reno, and McPherson Counties in Kansas. The death toll was 10 and 300 were injured. Damage was set at 1.3 million. The tornado path width reached 2 miles at one point. (Intellicast)
...1964...The temperature at White Mountain 2, located in California, dipped to 15 degrees below zero to set a record for May for the continental U.S. (The Weather Channel)
...1987...Thirty-one cities in the western U.S. reported record high temperatures for the date under a large high pressure area over the region. Highs of 93 degrees at Portland, OR and San Jose, CA were the warmest of record for so early in the season. The high of 92 degrees at Quillayute, WA was a record for the month of May. The temperature at Sacramento, CA hit 105 degrees, Fresno reached 103 degrees and Bakersfield had a high reading of 101 degrees. (The National Weather Summary)
...1988...A powerful storm in the north central U.S. produced up to three feet of snow in the Bighorn Mountains of Wyoming and the mountains of south central Montana. Up to five inches of rain drenched central Montana in less than 24 hours, and flash flooding in Wyoming caused a million dollars damage. (Storm Data) (The National Weather Summary)
...1989...Thirty-two cities in the central and eastern U.S. reported record low temperatures for the date, and 24 hour snowfall totals of 7.2 inches at Buffalo, NY and 10.7 inches at Rochester, NY were records for the month of May. While northerly winds ushered unseasonably cold air into the eastern U.S., temperatures warmed rapidly in the Great Plains Region, reaching the 90s in Kansas. The temperature at Manhattan, KS soared from a low of 30 degrees to a high of 88 degrees. (The National Weather Summary) (Storm Data)
...1990...Gale force winds lashed the northern and central Pacific coast. A wind gust of 52 mph at Eureka, CA established a record for the month of May. Strong winds over northeastern Colorado, associated with a fast moving Pacific cold front, gusted to 63 mph at Peetz. Snow developed over the northwest mountains of Wyoming late in the day, and Yellowstone National Park was whitened with 6 to 14 inches. (The National Weather Summary) (Storm Data)
...1995...An F3 tornado cut a 34 mile path across Love and Carter Counties in south-central Oklahoma, killing 3 people and doing over $100 million in damages -- $75 million in Ardmore alone. (Intellicast)

8 May

...1784...A deadly hailstorm in South Carolina hit the town of Winnsborough. An account was found in the South Carolina Gazette: "hailstones, or rather pieces of ice measured about 9 inches in circumference: it killed several persons. a great number of sheep, lambs, geese, and the feathered inhabitants of the woods without number". Piles of hail were reported still in existence 46 days later. (David Ludlum) (Intellicast)
...1803...A freak spring storm produced heavy snow from southern Indiana to New England. The storm made sleighing possible in Massachusetts, but also ruined shade trees in Philadelphia. (David Ludlum)
...1981...The Dallas/Fort Worth area experienced its worst hailstorm of record as baseball to grapefruit size hail, accompanied by 100 mph winds, caused nearly 200 million dollars damage. Two homes were destroyed and many more were damaged. These figures made it the worst severe thunderstorm in American weather history until 1990. Hail accumulated eight inches deep at Cedar Hill, TX. (The Weather Channel) (Intellicast)
...1987...Twenty-eight cities in the northwestern U.S. reported record high temperatures for the date. The record high of 95 degrees at Redding, CA was their fifth in a row, and the record high of 102 degrees at Hanover, WA was just one degree shy of their record for May. (The National Weather Summary)
...1988...Thunderstorms in the Mississippi Valley spawned a total of 57 tornadoes, including 24 in Wisconsin, and a record 22 tornadoes in one day in Iowa. One of the tornadoes in Iowa was on the ground for 67 miles from Bloomfield to Conesville. There were also more than 200 reports of large hail and damaging winds. Baseball size hail was reported at Terre Bonne, MO. At Rockford, IL one person was temporarily trapped inside a portable toilet toppled by thunderstorm winds gusting to 80 mph. Fortunately, not a single person was killed in the "Mother's Day" tornado outbreak. (The National Weather Summary) (Storm Data) (Intellicast)
...1989...Twenty-one cities in the eastern U.S. reported record low temperatures for the date. Lows of 28 degrees at Asheville NC and 31 degrees at Greer, SC were records for May. (The National Weather Summary)
...1990...Thunderstorms produced severe weather in northwestern and north central Kansas during the evening and night. Thunderstorms produced hail three inches in diameter at Brewster, and wind gusts to 92 mph south of Wakeeney. Thunderstorms over northwest Iowa deluged the town of Boone with five inches of rain flooding basements and leaving some areas under four feet of water. (The National Weather Summary) (Storm Data)
...1992...A vigorous upper level low pressure system stalled out over the Carolinas for the past 3 days unloaded tremendous amounts of snow over the western North Carolina mountains above 4000 feet. Mt. Pisgah (elevation 5721 feet) recorded an incredible 60 inches over the 3 day period, tying the all-time single storm snowfall record for the state. Mt. Mitchell (elevation 6684 feet) was buried under 30 inches of very wet snow. On the previous day, the Greenville-Spartanburg Weather Service Office in Greer, SC had snow mixed with rain, making this the latest date and the first time in may that snow had fallen at this location. (Intellicast)
...1995...Thunderstorms with torrential rains struck the New Orleans, LA area. Audubon Park recorded 8.5 inches of rain in only 2 hours. Several locations had over 14 inches total ending early on the 9th. 5 people were killed in the flooding and damage exceeded one billion dollars. (Intellicast)

9 May

...1894...Portland, OR had its latest freeze when the temperature fell to 32 degrees. This is the only May freeze in Portland's history. (Intellicast)
...1926...It was the latest opening of navigation on record at Buffalo, NY. (Intellicast)
...1927...A major tornado outbreak occurred from Texas to Michigan. There were 28 tornadoes rated F2 or greater. Nine separate tornadoes killed 5 or more people making this day one of the worst tornado days in U.S. history. Popular Bluff, MO was devastated by a tornado rated F4 on the Fujita scale. Ninety eight people were killed and 300 were injured. Thirty one business and residential blocks were destroyed in the city. Strong, AR was leveled by another F4 tornado with 24 people killed. (Intellicast)
...1933...A tornado, rated F4 on the Fujita Scale, moved through Monroe, Cumberland, and Russell Counties in Kentucky. 36 people were killed. (Intellicast)
...1966...Record snows fell in the northeastern Ohio and western Pennsylvania, including 3.1 inches at Pittsburgh, PA and 5.4 inches at Youngstown, OH. Snow also extended across parts of New York State, with eight inches reported in the southern Adirondacks. (The Weather Channel)
...1977...A late season snowstorm hit parts of Pennsylvania, New York State, and southern and central New England. Heavier snowfall totals included 27 inches at Slide Mountain, NY and 20 inches at Norwalk, CT. At Boston it was the first May snow in 107 years of records. The heavy wet snow caused extensive damage to trees and power lines. The homes of half a million persons were without power following the storm. (9th-10th) (David Ludlum) (The Weather Channel)
...1985...Lightning struck some trees about 150 yards away from a home in Alabama, and followed the driveway to the home. The charge went through the house and burned all the electrical outlets, ruined appliances, and blasted a hole in the concrete floor of the basement. (The Weather Channel)
...1987...Unseasonably warm weather spread from the Pacific Northwest to the Upper Mississippi Valley. Fifteen cities reported record high temperatures for the date. It was the fourth day of record warmth for Eugene, OR and Salem, OR. (The National Weather Summary)
...1988...A massive cyclone in the central U.S. produced severe thunderstorms from eastern Texas to the Upper Ohio Valley. A strong (F-3) tornado ripped through Middleboro KY causing more than 22 million dollars damage. Thunderstorms in east central Texas produced hail three and a half inches in diameter at Groesbeck, and near Fairfield. (The National Weather Summary) (Storm Data)
...1989...Thunderstorms developing ahead of a cold front in the south central U.S. produced golf ball size hail and wind gusts to 62 mph at Mira, LA, and during the morning hours drenched Stuttgart, AR with five inches of rain. (The National Weather Summary) (Storm Data)
...1990...Thunderstorms produced severe weather in the central U.S. during the evening hours, mainly from southeastern Missouri to southwestern Indiana. Severe thunderstorms spawned four tornadoes, including two strong (F-2) tornadoes in southern Illinois. Strong thunderstorm winds gusted to 85 mph at Orient IL, and to 100 mph at West Salem. Thunderstorms drenched northeastern Illinois with up to 4.50 inches of rain. (The National Weather Summary) (Storm Data)