DATASTREME DAILY SUMMARY

Wednesday, 13 September 2000


00Z Weather Systems


WELCOME TO DATASTREME - The Daily Weather Summary file will describe the current weather pattern across the U.S. The Tuesday and Thursday files will also contain the "Concept of the Day" with a question to be answered on the weekly Chapter Response Form. Additional Supplemental Information files will provide optional background material.

THE COLD FRONT PUSHES EAST -- An active cold front with severe thunderstorms that produced large hail and high winds on Monday across the western Great Lakes continued to push eastward on Tuesday. By Tuesday evening the cold front stretched from a low pressure area east of Hudson Bay southwestward across the eastern Great Lakes, the Ohio and lower Mississippi Valleys to the southern Plains before terminating as a stationary front over the Texas Panhandle. A long line of rainshowers and embedded thunderstorms was situated ahead of the front, extending from the Champlain Valley of Upstate New York and Vermont southwestward to western Pennsylvania, Maryland and the eastern West Virginia Panhandle. Some of the thunderstorms turned severe as they moved across New York State on Tuesday afternoon. Wind damage was reported across the Mohawk Valley near Syracuse and an injury was sustained by a tree falling on a car near Oswego.

Heavy rain fell along the cold front, the result of the abundant supply of moisture brought northward by winds from the Gulf of Mexico. On Monday Detroit, MI received 3.71 inches of rain, which was not only a daily precipitation record, but also was the greatest daily total recorded there during the month of September since records began in 1870. Milwaukee, WI had 2.96 inches, a daily rainfall record. On Tuesday morning Joplin, MO received a record-setting 1.12 inches of rain, which also was its first measurable precipitation in 25 days.

By Wednesday morning northern sections of the cold front are expected to have reached the New England coast, with most of the precipitation confined to coastal New England. The southern portion of the front is anticipated to reach the Tennessee Valley by morning and to stall across the midsections of the Gulf Coast states of Georgia, Alabama and Mississippi.

PLEASANT WEATHER ACROSS THE MIDWEST -- Cool Canadian high pressure followed the passage of the cold front into the Upper Midwest on Tuesday. This high pressure was centered over northern Missouri by evening. Northwesterly winds (from the northwest) circulating around the east side of the high brought dry air with relatively sunny skies and seasonal temperatures across the Upper Mississippi Valley, in marked contrast to the warm and muggy conditions experienced prior to frontal passage.

On Wednesday as the high pressure system moves eastward toward the Ohio Valley, winds are expected to turn southerly with an increase in the temperatures as a warm front associated with a weak low pressure system approaches from the Plains.

MORE RECORDS IN TEXAS -- Hot weather continued across portions of Texas on Tuesday. Daily record high temperatures were established at Del Rio (105 degrees) and Austin (100 degrees at both Mabry and Bergstrom Field).

Some relief from the extended Texas dry spell was afforded by thunderstorms that developed across the Lone Star State on Tuesday. As of late Tuesday night a large area of thunderstorms was found across Texas, extending from the Big Bend eastward across the Hill Country to east Texas near Houston and then into Louisiana. These thunderstorms were associated with an elongated east-west oriented trough of low pressure. Severe thunderstorms with hail were reported across central Texas near Abilene on Tuesday evening. Some wind damage was sustained in 70 mph winds. The thunderstorms also ended the 72 day long dry spell in Abilene, one day short of the record number of days without precipitation. While rain fell in the Dallas-Fort Worth metropolitan area, no rain was recorded at the DFW airport where the official climate record is maintained, thereby continuing the official dry spell of 74 days without rain.

Additional rain associated with the trough of low pressure is expected along the Texas Gulf Coast on Wednesday. As much as an inch of rain could fall in the 24 hours commencing on Wednesday morning for a region to the north and east of Galveston.

FEELING THE EFFECTS OF LANE -- Clouds were on the increase across southern and central California as a result of the northward movement of Tropical Storm Lane along the coast of Baja California. Lane also generated ocean swell that propagated northward. Surf from this swell ranged between 3 to 6 feet on the south facing beaches of Ventura and Los Angeles counties of southern California.

YESTERDAY'S TEMPERATURE EXTREMES ACROSS THE CONTINENTAL US -- Tuesday morning's lowest temperature was 27 degrees at Fraser, CO, while the highest temperature on Tuesday was 111 degrees at Lake Havasu City, AZ and Thermal, CA.

ALASKAN WEATHER -- Cloudy and cool conditions along with widespread light precipitation were found across Alaska on Tuesday, the result of several weak areas of low pressure. One low pressure system was situated over Bristol Bay with an accompanying front extending over the Alaska Peninsula. Another weaker low pressure trough was found along the Alcan border in the Upper Yukon Valley. Light snow fell along the Arctic Coast at Barrow and Nuiqsut.

The state's lowest overnight temperature on Tuesday morning was 25 degrees at Noatak. The highest temperature by mid afternoon of Tuesday was 59 degrees at Ketchikan and Klawok.

HAWAIIAN WEATHER -- A high pressure system located to the north of Hawaii produced moderate trade winds across the islands on Tuesday. These easterly winds (from the east) are located on the equatorward flank of the subtropical high as part of the clockwise circulation. The high pressure system is expected to move southward during the second half of the week, resulting in a slight weakening of the trades. A few trade showers will continue on the windward slopes of the islands, while sunny skies will prevail elsewhere.

EYE ON THE TROPICS -- On Tuesday afternoon Tropical Storm Florence in the western Atlantic Ocean was upgraded to hurricane status as the winds surrounding the low pressure system increased above the 75 mph minimum. As of Tuesday night, Florence was a minimal hurricane with sustained near surface winds at 75 mph and it was moving to the northwest at 5 mph some 310 miles to the south-southeast of Cape Hatteras, NC.

In the eastern North Pacific, Tropical Storm Lane continued to move along the western coast of Baja California. As of Tuesday night Lane had sustained winds of 45 mph and was 875 miles to the northwest of Cabo San Lucas, Mexico with movement to the northwest at 12 mph.

SOMETHING SPECIAL IN THE SKY: THE HARVEST MOON -- A full moon will occur during today, 13 September at 1937 Z (3:37 PM EDT, 2:37 PM CDT, etc.). Even though the full moon of September is called the "Fruit Moon", this full moon is called the "Harvest Moon" because of its proximity to next week's autumnal equinox. For additional information, consult the optional Wednesday Supplemental Information.


HISTORICAL WEATHER EVENTS - 13 September

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


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