DATASTREME DAILY SUMMARY

Tuesday, 6 November 2001


00Z Weather Systems


Today is Election Day in nearly two dozen large cities along with two states with gubernatorial races. If you live in one of these cities or states, exercise your right to vote.

The following discussion is based upon the major weather features appearing on Monday night's surface weather maps:

ANOTHER WARM NOVEMBER DAY -- Quiet weather conditions prevailed across much of the country on Monday, except for unsettled weather across the Northeast, Southeast, Southwest and Northwest. High pressure located over the Great Lakes brought clear skies across the Plains and the Mississippi Valley. Another high pressure cell was also located over the central Rockies.

Afternoon high temperatures across much of the nation's midsection were above average, with the largest departures occurring in the northern Plains where some stations in the Dakotas and northern Minnesota had highs that were as much as 30 degrees above the long-term average highs for the date. Record high temperatures were either tied or set on Monday afternoon in Nebraska at Valentine (83 degrees), Alliance (79 degrees), Chadron (79 degrees), Sidney (77 degrees) and Hastings (75 degrees); in South Dakota at Huron (80 degrees), Mitchell (80 degrees), Sioux Falls (75 degrees) and Watertown (73 degrees); in Minnesota at Minneapolis/St. Paul (71 degrees); in Wyoming at Rawlins (64 degrees); in Colorado at Yuma (77 degrees) and in Montana at Miles City (73 degrees), and Helena and Belgrade (both 68 degrees).

The pleasant November weather is expected to continue on Tuesday as the high pressure system over the Lakes is expected to drift slowly toward the east. A cold front across the northern Rockies is expected to travel southeastward across the northern Plains on Tuesday resulting in anticipated temperatures that should be less than those experienced on Monday.

UNSETTLED WEATHER ACROSS THE NORTHEAST -- A storm system moved across the Northeast on Monday, accompanied by clouds, precipitation and windy weather. As much as six inches of snow fell in several locations across Maine earlier on Monday. With northerly winds along with clouds and precipitation, high temperatures across the Northeast were slightly below the long term averages for early November. The low pressure system had moved off shore and was situated near Cape Sable in Nova Scotia during mid-evening. However, a broad area of rain associated with this system continued to fall across coastal New England, from eastern Connecticut north to "Downeast" Maine. A relatively tight pressure gradient remained across New England resulting in continued strong northwesterly winds. With winds expected to continue with speeds between 39 to 54 mph, gale warnings were in effect for coastal waters from Sandy Hook, NJ to Eastport, ME. These warnings did not cover Long Island Sound.

The storm system is expected to remain along the coast of Nova Scotia on Tuesday. As a result, precipitation is expected to linger over northern New England, with snow possible over interior and upland Maine. Between 0.25 and 0.50 inches could fall in the 24 hours ending on Tuesday evening across New England.

SOME WET AND WINDY WEATHER ACROSS SOUTH FLORIDA -- Hurricane Michelle passed to the south and east of south Florida early Monday leaving much of the Sunshine State relatively unscathed. Most areas received less than an inch of rain and most wind gusts were less than 40 mph. However, rain continued to fall across the Miami area in south Florida as of Monday evening. During the afternoon a waterspout came on shore near Key Biscayne, to become a tornado as it traveled through a recreational area. An unconfirmed tornado was suspected of causing damage near Palm Beach.

Easterly winds are expected to continue across the Florida Peninsula. As a result, heavy surf advisories remained in effect for Florida's Atlantic coast, extending northward from Jupiter Inlet to Altamaha Sound in coastal Georgia. Some additional rainshowers could remain across south Florida on easterly flow.

MORE RAIN FOR THE SOUTHWEST -- Rainshowers and embedded thunderstorms continued across portions of southern Arizona and New Mexico on Monday in association with a weak area of low pressure situated over southeastern California.

Scattered showers and thunderstorms are expected to continue across Arizona and New Mexico on Tuesday, with 24 hour precipitation totals by evening ranging from 0.01 to 0.30 inches.

WIDELY SCATTERED PRECIPITATION IN THE NORTHWEST -- A prevailing westerly wind flow produced some precipitation along the various mountain ranges. Most of the precipitation was falling as rain, except for some snow at higher elevations of Idaho and Montana. The westerly flow is behind a cold front that moved into the Pacific Northwest over the weekend.

A wave is forecast to develop in the nearly stationary front across Idaho, Montana and Wyoming. This disturbance could produce snow across the northern Rockies by Tuesday afternoon.

UPPER AIR -- Both the 500 and 300 mb charts for 00Z Tuesday reveal the development of a height ridge that has developed across the nation's midsection, reflecting a region of warm air that extends upward through the troposphere. A height trough is found along the East Coast on both pressure surfaces, associated with the cold air and surface storm system located off the Maine coast. The jet stream, representing the band of strongest winds at 300 mb, remains well to the north, moving onshore across the Northwest, then deflected northward around the northern flank of the ridge in the Mississippi Valley and then traveling around the southern extremity of the trough in the East.

TEMPERATURE EXTREMES IN THE LOWER 48 -- The lowest temperature on Monday was 11 degrees at Plentywood, MT, while Monday's highest temperature was 91 degrees at Thermal, CA.

ALASKAN WEATHER -- A ridge of high pressure extended westward along the North Slope from a high pressure center located over the Mackenzie Delta of northwest Canada. Arctic air has expanded across much of Alaska, with a stationary front along the Gulf coast forming the southern boundary of the cold air mass. Some locations across the north and interior experienced relatively clear skies, while other locations had clouds and snow. Snow was reported at Fort Wainwright, Nome and King Salmon. A weak low was located in the eastern Gulf of Alaska west of Sitka. Rain and snow were found across southeast Alaska and the Panhandle. A large and major storm system moving eastward across the western Bering Sea was responsible for hurricane force winds and some light precipitation across the Aleutians. An occluded front extended southeastward across the Bering Sea and the western Alaska Peninsula into the North Pacific Ocean.

The state's lowest temperature on Monday morning was 15 degrees below zero at Selawik. The highest temperature across Alaska as of midafternoon on Monday was 45 degrees at Atka.

HAWAIIAN WEATHER -- A band of clouds and showers moved westward across the windward sections of the Big Island and Maui on Monday afternoon. These showers were expected to reach Oahu by evening and Kauai by midnight. A bigger band of clouds and showers that represent the remnants of former Hurricane Octave is farther east and could reach the islands on Wednesday.

The trade winds weakened sufficiently so as to permit cancellation of the small craft advisories for state waters.

EYE ON THE TROPICS -- Hurricane Michelle moved across the Bahamas on Monday and continued toward the northeast. As it moved across Cuba on Sunday night, Michelle was responsible for at least five deaths along with considerable damage to some buildings. Electric power and communications to the western part of the island were disrupted. As of early Tuesday morning, Hurricane Michelle was located 550 miles southwest of Bermuda and moving to the east-northeast at 21 mph. Maximum sustained surface winds were 85 mph. Estimated central pressure was 977 mb.

On Monday a low pressure system with tropical characteristics developed rapidly into Hurricane Noel, the ninth hurricane of the season, over the North Atlantic. However, by early Tuesday Noel had weakened back to tropical storm status. Tropical Storm Noel with maximum sustained winds of 65 mph was located 365 miles southeast of Cape Race, Newfoundland and moving to the north at 20 mph.

REPORT FROM THE FIELD -- Vivid northern lights (or aurora borealis) were seen by this reporter from outside his house near Madison, WI on Monday night.


CONCEPT FOR THE DAY - ATMOSPHERIC SCALES

Atmospheric motions, from the swirl of leaves across the parking lot to jet streams encircling the globe, are all related. The seemingly vast complexity of weather can be divided into combinations of a relatively few sizes and time ranges for study. Usually, the larger the motion, the longer it will last. In addition, different types of motion have variations in forces that dominate the action. The largest persistent flows across the planet extend high into the atmosphere where friction is small enough to be ignored. The smallest momentary breezes are essentially free of the Coriolis effect.

Meteorologists refer to the largest, most persistent atmospheric motions as part of the planetary-scale. The DataStreme course has thus far concentrated on the high and low pressure systems of the synoptic or macroscale. Smaller weather features such as thunderstorms dominate the mesoscale. The smallest movements of air, such as wind gusts or turbulence, constitute the microscale. For more detail on the traditional arrangement of the subdivisions according to space and time scales, together with their observation strategies, see the Tuesday optional Supplemental Information .

QUESTIONS:

To be submitted on the lines for Tuesday on the Study Guide, Part B, Applications, Week 9 Chapter Progress Response Form, under section B. Daily Summary.

  1. The largest size atmospheric features are [(macro-), (meso-), (micro-), (planetary-)] scale features.
  2. Thunderstorms are considered to be [(macro-), (meso-), (micro-), (planetary-)] scale systems.

HISTORICAL WEATHER EVENTS - 6 November

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


Return to DataStreme Homepage

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