DATASTREME DAILY SUMMARY

Monday, 22 October 2001


00Z Weather Systems


WEATHER OVER THE WEEKEND -- Much of the country experienced warm, pleasant and relatively tranquil autumn weather for the first half of the weekend. The only notable exception was south Florida where persistent rains continued to fall throughout the weekend from rainshowers and thunderstorms that developed along a stalled stationary front.

The air mass that had produced record low temperatures across the Southeast during much of last week had moderated and moved off the East Coast. As a result, no new record low temperatures were established on Friday morning.

A cold front that was moving across the western Great Lakes on Thursday night reached the East Coast on Saturday. Some rain developed ahead of this front over the eastern Lakes and moved eastward across the Northeast.

A relatively mild air mass of Pacific origin spread eastward across the country, resulting in afternoon high temperatures across much of the nation that were at or above the average highs for mid October. This air mass was associated with high pressure that was situated over the Great Basin on Friday, resulting in afternoon temperatures that were on the order of 10 degrees above average. High temperatures on Saturday were also above average, the western Plains and the central Rockies experiencing high temperatures that were on the order of 10 to 15 degrees above average. In Arizona, a record high temperature was reached on Saturday at Douglas (88 degrees) and on Sunday at Safford Ag. Station (90 degrees). On Sunday, afternoon high temperatures across the Northeast were 10 to 15 degrees above average. A record high temperature was reached at Jackson, KY (78 degrees). Only the Pacific Northwest and the California coast had below average afternoon high temperatures as a cold front approached the West Coast. Clouds and a cool, onshore wind in the San Francisco Bay area caused several locations to set new low high temperature records to include Downtown San Francisco (55 degrees), San Francisco's Airport (57 degrees), Oakland's Airport (57 degrees) and Monterey (57 degrees).

A cold front moved southward from the Prairie Provinces into the northern Plains on Saturday and by Sunday morning this front was located over the mid-Mississippi Valley. Some thunderstorms developed along and ahead of this front that then essentially stalled over southern Iowa during the afternoon. During the mid to late afternoon hail-producing thunderstorms moved across southern Iowa and northern Missouri. Some of the hail had diameters that were an inch in diameter. Severe thunderstorms also moved across northern Pennsylvania and into the Finger Lakes and Mohawk Valley of western New York State. These thunderstorms were accompanied by damaging winds and large hail, with diameters of up to 1.00 inch in diameter. A storm report filed from Lyndon south of Buffalo in western New York State indicated that the roof ripped off a barn and forty 1000 bales of hay "vanished"; a funnel cloud was also reported.

Who says that lightning only strikes in summer? A 13-year old soccer player and a coach were struck by lightning at a soccer game in Duluth, MN on Saturday afternoon as a thunderstorm quickly developed over this Northland community on the western end of Lake Superior. As of Saturday night the youth from near Clouquet remained in critical condition while his coach was treated and released. The thunderstorm quickly developed because of an unstable atmospheric environment with cold air aloft. Players had dropped to the ground as the lightning struck. In addition to the one lightning stroke that hit the soccer complex, hail also fell.

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.

A cold front stretched southwestward from low pressure in eastern Canada across the lower Great Lakes to the mid-Mississippi Valley, where it became a stationary front that continued across the Plains to the Oklahoma Panhandle. Rainshowers and embedded thunderstorms continued to be found along and in the vicinity of these cold and stationary fronts. Some of the precipitation was found across northern New England and portions of New York State. However, the more active weather continued across the Midwest. Severe thunderstorms accompanied by large hail were still moving across west central Illinois at local midnight. Because of the more than 3 inches of rain estimated by Doppler radar to have fallen during the evening, a small stream and urban flood advisory was posted through early Monday morning for several counties in southeast Iowa, west central Illinois and northeast Missouri. With moisture available from afternoon thunderstorms and overnight cooling, dense fog that was restricting visibility to several hundred feet was beginning to form across western New York State, resulting in the issuance of dense fog advisories. Dense fog advisories were also posted for portions of northern Ohio and northwest Pennsylvania.

While the cold front is expected to continue moving eastward on Monday, the stationary portion of the front is forecast to remain anchored over the mid-Mississippi Valley. The cold front should reach the coast of New England by sunrise, with high pressure building in across the lower Lakes in the wake of the front. A large area of heavy rain and thunderstorms is anticipated to continue over the Midwest through Monday. A large section of the mid-Mississippi Valley is expected to have a slight risk of severe weather on Monday, covering an area that extends northeastward from northeast Oklahoma to southern Lake Michigan. As much as one inch of rain is anticipated to fall across Iowa during the 24 hours ending on Monday night. Between 0.1 and 0.3 inches of rain is also forecast for this same time interval across the Northeast in association with the cold front.

Heavy rain and thunderstorms continued to fall across the southern half of the Florida Peninsula on Sunday evening. This precipitation was associated with a trough of low pressure that represented the dissipated stationary front that had lingered over the region for nearly one week. Rain and thunderstorms should continue on Monday, with as much as 1.5 inches of rain possibly falling during 24 hours ending by evening.

A weak low pressure system was moving across the northern Rockies on Sunday night. A cold front trailed southwestward across Idaho and Oregon from the low that was centered over central Montana. Some light, widespread precipitation associated with this system was found across the Pacific Northwest. On Monday, the low pressure center is expected to move toward the east-northeast, reaching eastern Montana by sunrise and the Red River Valley separating the eastern Dakotas and western Minnesota by evening. Some precipitation, with amounts on the order of 0.1 inches, is expected across the northern Plains.

An intense storm system that is expected to intensify over the Gulf of Alaska is forecast to sweep toward the British Columbia coast on Monday. A cold front associated with the storm system is anticipated to make landfall along the Washington State coast by late afternoon. With the approach of this developing strong storm, a high wind watch was posted for Monday afternoon along the Washington and much of the Oregon coasts for southerly winds of 35 mph with gusts to 65 mph near the coastal headlands. In anticipation of possible 25 foot high waves that could be generated by this approaching storm, a coastal flood watch was in effect for the Washington State coast, effective for Monday night and Tuesday.

The cold front is expected to move inland late Monday. As a result, a winter storm watch was posted for the Olympics and west slopes of the Cascades of Washington State from Monday night until daybreak on Tuesday as a foot of new snow could fall at elevations above 4000 feet. Winds with gusts to 50 mph were also possible. A winter storm watch was also issued for the mountains of northwest Montana, to include the Bitterroots, and the Clearwater Mountains of northern Idaho, as 6 to 12 inches of snow could fall between Monday evening and Tuesday afternoon, accompanied by southwesterly winds with gusts to 50 mph. Additional winter storm watches were posted for the west central Idaho mountains where 6 to 8 inches of snow could fall above 6000 feet and in the upper Snake highlands of eastern Idaho, where 4 to 6 inches are possible.

TEMPERATURE EXTREMES ACROSS THE LOWER 48 -- On Sunday, the lowest temperature reported in the continental U.S. was 11 degrees at Big Piney, WY, while Sunday's highest temperature was 97 degrees at Casa Grande, AZ.

ALASKAN WEATHER -- A storm system located over south central Alaska was responsible for windy conditions along with clouds and some precipitation across southern Alaska. This storm consisted of a low pressure center located near Anchorage and a weakening front that extended along the southeast Gulf coast. Nearly an inch of rain fell at Annette, Yakutat and Haines. Snow fell at King Salmon, Saint Paul Island and Talkeetna. A high pressure ridge located across the Arctic Ocean north of Barrow influenced the weather across the Arctic Slope and northwest Alaska. The midafternoon temperature at Anaktuvuk was 2 degrees below zero. A northeasterly onshore flow produced clouds and snow at Barrow and Nuiqsut. Snow was also reported at Kaltag and Cantwell. Farther south, partly cloudy skies were found across interior Alaska. Delta Junction reported wind gusts to 43 mph.

The lowest overnight temperature in Alaska as of Sunday was 11 degrees below zero at Anaktuvuk Pass and the midafternoon highest statewide temperature was 48 degrees at Hydaburg and Sitka.

HAWAIIAN WEATHER -- Moderate trade winds were found over the Aloha State on Sunday afternoon as a result of a large ridge of high pressure located to the north of the islands. Trade showers were found along the windward or northeast slopes of the islands. On Monday, the trades are expected to weaken as a cold pool of air in the mid to upper troposphere approaches from the northeast. Increased humidity along with decreased atmospheric stability should increase the chance of thunderstorms over the Big Island and Maui by midweek. High surf advisories were in effect for the northeast shores of the Big Island.

EYE ON THE TROPICS --In the Eastern Pacific, a tropical depression formed more than 1000 miles off the Mexican coast on Saturday morning and by midday had intensified into Tropical Storm Narda, the thirteenth named tropical system of the season. By Sunday afternoon, Narda had intensified and become a hurricane. As of Sunday evening, Hurricane Narda had maximum sustained surface winds of 85 mph and was located 1535 miles to the west-southwest of Cabo San Lucas, Mexico. Movement was to the west-northwest at 10 mph.

WINTER AWARENESS -- Several states are observing their Winter Weather Awareness Week during this upcoming week (22-28 October) to include California (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.


HISTORICAL WEATHER EVENTS - 22 October

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


Return to DataStreme Homepage

URL Address: datastreme/learn/m_sum.html
Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2001, The American Meteorological Society.