HAPPY NEW YEAR -- Today is Rosh Hashanah, the Jewish new year. However, the observance began at sundown on Monday. The Jewish new year falls on the day following the new moon nearest the autumnal equinox. This month's new moon was on Monday morning (1027 Z on 17 September) and the autumnal equinox will be this Saturday (22 September). The upcoming year in the Jewish calendar is 5762.
The following discussion is based upon the major weather features appearing on Monday night's surface weather maps:
ACTIVE WEATHER ACROSS THE PLAINS -- An east-west oriented stationary front that stretched across the central Plains served as a focal point for thunderstorm activity across the region for another day. The front, with several weak low pressure centers, stretched from the Texas Panhandle eastward to Missouri and then northeastward into central Illinois. This front separated warm, moist tropical air to the south of the front from cooler and drier air that was residing across the northern Plains. Widespread rain and embedded thunderstorms continued to the north of the front, extending across Kansas, the Nebraska Panhandle, and into Illinois. Some severe thunderstorms continued across the Red River Valley of southern Oklahoma and north Texas well to the south of the front.
This front has had a history of producing heavy rains and severe thunderstorms. Earlier, thunderstorms generated some high winds that caused structural damage to buildings near Newton in south central Kansas and blew over some trucks near Wichita Falls in north Texas early Monday evening. Some of these winds were measured at 70 mph. Large hail with diameters as large as 2.50 inches fell across portions of eastern Colorado, western and central Kansas, and the Panhandles of Oklahoma and Texas. Rainfall was sufficiently heavy in some locales to produce flash flooding. Roads were flooded in western and central Kansas.
A low pressure system is expected to develop along the western end of the front and move toward the east on Tuesday. By evening, the portion of the front west of the low is forecast to move southward across Oklahoma and west Texas as a cold front. A slight risk of severe thunderstorms continues through Monday night into Tuesday morning across the Plains, to include much of Kansas, western Oklahoma, the Texas Panhandle and portions of eastern New Mexico and Colorado. During Tuesday, the slight risk of severe weather shifts eastward to stretch from the Red River Valley of north Texas into the mid-Mississippi Valley in the vicinity of St. Louis, MO. The precipitation associated with this front should move toward the east along with the low pressure center. However, between 1.0 to 2.7 inches of rain could fall across central Kansas and western Missouri during the 24 hours ending on Tuesday evening. As a result of the heavy rains of the last few days coupled with the anticipated rains, flash flood watches have been posted for the eastern half of Kansas, the western quarter of Missouri and a portion of southeastern Nebraska.
SHOWERS CONTINUE ACROSS THE ROCKIES -- Widely scattered rainshowers and thunderstorms were found across the Rockies and Intermountain West. Several thunderstorms along the western slopes of the Colorado Rockies produced some wind damage and large hail during the midday hours of Monday.
PLEASANT WEATHER ALONG THE EASTERN SEABOARD -- A large, elongated ridge of high pressure extending along the Eastern Seaboard provided the region with another day of pleasant weather with seasonal high temperatures and relatively clear skies. However, the clear skies, low humidities and weak winds have allowed for considerable nighttime cooling as heat is lost to space by radiation. Daily record low temperatures were either tied or set in South Carolina at Columbia (46 degrees) and at the Charleston Airport (56 degrees) and in Florida at Tallahassee (52 degrees), Jacksonville (60 degrees), Lakeland (65 degrees), Daytona Beach (65 degrees) and Orlando (66 degrees).
COOL WEATHER ACROSS THE LAKES -- A cold front trailing westward across Lake Superior and the upper Midwest represented the leading edge of a cold air mass associated with a high pressure system over western Ontario. Some light precipitation was found across the Great Lakes to the south of the front. However, this front is expected to stall, becoming a stationary front by early morning. The Canadian high pressure is forecast to move eastward into Quebec by Tuesday evening. Easterly winds should keep the northern Great Lakes cool. Some light precipitation could also continue just to the south of the front.
TEMPERATURE EXTREMES IN THE LOWER 48 -- The lowest temperature on Monday was 27 degrees at West Yellowstone and Wisdom, MT, while Monday's highest temperature was 109 degrees at Death Valley, CA.
ALASKAN WEATHER -- A weakening storm system in the Gulf of Alaska continued to spread rain across much of southeast Alaska. This storm system consisted of a low pressure center located south of Prince William Sound and an accompanying front that ran along the shore of the Panhandle. Rain fell at Whittier, Cordova and at several locations along the Panhandle. A strong storm system located over eastern Siberia was accompanied with a front that trailed southeastward across western Alaska. This front was responsible for clouds and light precipitation across western portions of the state. To the east of the front partly sunny skies were found across interior Alaska, a result of a large high pressure cell centered over northwest Alaska. Another high pressure cell stretched northward from the north central Pacific Ocean across the eastern Aleutians. Farther west, two storm systems were moving across the central and western Aleutians.
The state's lowest temperature on Monday morning was 23 degrees at Eagle. The highest temperature across Alaska as of midafternoon on Monday was 68 degrees at Skwentna and Talkeetna.
HAWAIIAN WEATHER -- Pleasant trade weather, with relatively cloud-free skies and moderate trade winds were found across Hawaii on Monday. The thin high clouds found across Kauai and Oahu earlier in the day have dissipated as a trough of low pressure continues to move westward away from the islands. An elongated ridge of high pressure located approximately 800 miles north of Honolulu was responsible for the east to northeast trade winds that had speeds ranging from 10 to 25 mph. Some isolated trade showers were found over the windward or northeast facing coasts of the islands.
High surf advisories were found on both the south and northwest facing shores of all islands.
EYE ON THE TROPICS -- After briefly reaching hurricane status on Sunday, Tropical Storm Gabrielle weakened as it continued to move across the western Atlantic toward the northeast. It also was losing its tropical characteristics as it moved. Bermuda had thunderstorms and wind gusts to 55 mph when the storm passed on Monday morning. As of late Monday night, Tropical Storm Gabrielle had maximum sustained surface winds of 65 mph and was approximately 375 miles north-northeast of Bermuda, with a forward speed of 21 mph to the northeast.
Tropical storm Felix, with sustained surface winds of 50 mph, was drifting across the Atlantic 320 miles south of the Azores.
REPORT FROM THE FIELD -- Toni Lynne DeVore, Project Atmosphere AERA and former DataStreme LIT Leader from Parkersburg, WV reported that the cool Canadian air mass that has resided over the Ohio Valley recently has been very welcome because many classrooms in that region of West Virginia do not have air conditioning. She also reported that with cool night weather, considerable fog has been experienced in the Parkersburg area.
Weather at a particular location is like one piece of a jigsaw picture puzzle. Observations of atmospheric conditions at one place, just as a single puzzle piece, cannot reveal the whole picture. Weather systems that typically dominate local weather can stretch over areas thousands of kilometers in breadth. Only through the analysis of local observations made at many locations at the same time can these changing and moving systems be delineated. Weather maps permit (1) convenient reporting of numerous single-site observations, and (2) depiction of existing broad-scale "weather makers" resulting from analysis of the observational data.
Local observations are depicted on weather maps as numbers and symbols plotted in, on, and around circles drawn at each station location, forming a "station model". The station model on which DataStreme maps are based can be seen by clicking on the DataStreme Homepage "DataStreme Weather Map Symbols" . More details are provided in DataStreme Activity 2A and Tuesday's optional electronic Supplemental Information .
Weather systems change over time while moving across the earth's surface. Studying recent and current weather maps allows us to follow the progress of weather systems. These maps provide valuable information to the weather forecaster who needs to know what the weather was and is in order to predict what the weather will be.
To be submitted on the lines for Tuesday on the Study Guide, Part B, Applications, Week 2 Chapter Progress Response Form, under section B. Daily Summary.
From the files of the Aviation Weather Center, Kansas City, MO and Intellicast
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URL: datastreme:/learn/t_sum.html
Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2001, The American Meteorological Society.