The following highlights of the national weather have been extracted from the surface weather map for Tuesday night:
THE RAINS RETURN TO THE WEST -- After a long hot summer with little significant rain, widespread precipitation moved across much of the West on Tuesday. Most of the precipitation that fell across the Sierras of California was in the form of rain, with snow at elevations above 6500 feet. Approximately 6 inches of snow fell near the crest of the northern Sierras. At lower elevations, between 0.3 and 0.5 inches of rain fell. The cooperative observer station at Priest Rapids Dam in eastern Washington received 0.31 inches of rain in the 24 hours ending on Tuesday evening, nearly doubling the previous record for this period.
Precipitation should fall across a large area of the West on Wednesday as a new front moves into the Pacific Northwest. This occluded front trailed southward from a storm system over the Gulf of Alaska on Tuesday night. By Wednesday evening the 24 hour precipitation totals across the western slopes of the Olympics and the Cascades in Washington, as well as the mountains of northern Idaho and northwest Montana could be between 1.0 and 1.6 inches of precipitation. Several tenths of an inch could fall across the Sierras in California, while approximately 0.7 inches of precipitation are anticipated over the mountains of Utah and the western slopes of the Colorado Rockies. A snow advisory was posted for most of the mountains of Utah, extending from the northern Wasatch in southeastern Idaho southward to the southwest mountains of the Beehive State. Between 4 to 10 inches of snow was anticipated at elevations above 7500 feet.
A high wind watch was in effect for the Rocky Mountain Front in western Montana and the adjacent Plains to the east, as southwesterly winds gusting to 50 mph were expected through Wednesday.
WET WEATHER ACROSS THE LAKES -- A large area of rain moved eastward across the Great Lakes on Tuesday evening. This rain was located to the north of a warm front that extended eastward from a weak area of low pressure in Wyoming across the Plains to the Ohio Valley. Warm air moving northward across the southern Plains and Mississippi was being carried aloft over the cooler air located to the north of the warm front. This overrunning was responsible for the precipitation to the north of the front.
To the south of the warm front, high temperatures across the western Plains and central Rockies ranged between 10 to 15 degrees above the average highs for the end of October. Rawlins, WY had a low temperature of 45 degrees, which was a record low high temperature, and an afternoon high of 66 degrees, setting a record high.
The warm front is expected to move slowly northward on Wednesday, reaching the southern shores of Lake Superior by evening. Between 0.1 and 0.5 inches of rain could fall during the 24 hours ending on Wednesday evening across the entire Great Lakes from eastern Wisconsin to Upstate New York.
TRANQUIL WEATHER CONTINUES ACROSS THE SOUTHEAST -- A ridge of high pressure extending southwestward across the Southeast has maintained relatively cloud-free skies and low humidities. The only area experiencing rainshowers and thunderstorms was found over South Florida.
WARM WEATHER CONTINUES ACROSS THE SOUTHWEST -- Record high temperatures were either tied or set on Tuesday in Arizona at Tucson (94 degrees), Safford (91 degrees), Nogales (90 degrees) and Douglas (90 degrees). Tuesday's high temperature in Tucson represents the highest temperature for so late in the season.
YESTERDAY'S TEMPERATURE EXTREMES ACROSS THE CONTINENTAL US -- Tuesday morning's lowest temperature was 18 degrees at Pellston, MI and Silver Bay, MN, while the highest temperature on Tuesday was 95 degrees at Davis-Monthan AFB near Tucson, AZ.
ALASKAN WEATHER -- High pressure centered over interior Alaska brought relatively sunny skies to a large portion of the state on Tuesday afternoon. This high extended from near Norton Sound eastward into the Upper Yukon Valley. To the south, cloudy skies and some light precipitation were associated with two large storm systems. One storm, with a central pressure of 976 mb, was located in the eastern Gulf of Alaska near the Queen Charlotte Islands. This storm was affecting the weather across the Panhandle. The other storm was moving across the southern Bering Sea just to the north of the central Aleutians. That low pressure system had a central pressure of 972 mb and an occluded front that stretched to the southeast across the western Alaska Peninsula. Snow fell along the Arctic coast and across portions of the interior, while light rain fell across the Panhandle as well as at St. Paul. Cold Bay had wind gusts to 44 mph during the afternoon, while Gambell and Metlakatla reported gusts to near 30 mph.
The state's lowest overnight temperature on Tuesday morning was 17 degrees below zero at Farewell Lake and Stoney River. The highest temperature by mid afternoon of Tuesday was 47 degrees at Annette and Klawock.
HAWAIIAN WEATHER -- A large high pressure located approximately 700 miles to the north of the Aloha State maintained northeast trade winds across the islands that had speeds ranging between 15 to 30 mph. Isolated nighttime trade showers were found over the windward slopes of the islands. The trades are expected to weaken slowly through the rest of the week as the high to the north weakens. Gale warnings remained for the Alenuihaha Channel between Maui and the Big Island, while small craft advisories remained for the rest of state waters.
EYE ON THE TROPICS -- Tropical Depression 15 continued to drift northward along the coast of Nicaragua. Heavy rains continued to fall across Nicaragua and Honduras. As of Tuesday evening TD 15 was located approximately 20 miles west of Puerto Cabezas, Nicaragua and moving to the north at 5 mph. Maximum sustained surface winds were 35 mph. If this system continues to drift northward, it could intensify into a tropical storm over the warm waters of the Gulf of Honduras.
In the central North Atlantic, Tropical Storm Lorenzo has curved toward the north and finally toward the north-northeast. As of late Tuesday night, Lorenzo was 965 miles west of the Azores and moving toward the north-northeast at 26 mph. Maximum sustained surface winds were 40 mph.
In the Eastern Pacific, Tropical Depression 17 E formed on Tuesday. By early Wednesday morning, this tropical depression had intensified to become Tropical Storm Octave, the fifteenth named tropical system of the season. Its position was 1185 miles southwest of Cabo San Lucas, Mexico and its movement was to the west-northwest at 14 mph. Maximum sustained surface winds were 45 mph.
HALLOWEEN -- Wednesday is Halloween, derived from "All Hallowed Eve" since it is associated with a Christian observance, All Saints Day (1 November). However, today's festivities date back to pre-Christian times because today represents the "cross quarter" day marking the halfway point between the autumnal equinox (22 September 2001) and the winter solstice (21 December 2001).
THE HUNTER'S MOON -- A full moon will occur late tonight (more precisely, at 0541 Z on 1 November or 12:41 AM EST, 11:41 PM CST on 31 October, etc.). This full moon is often called the "Hunter's Moon" since it follows the more spectacular "Harvest Moon" (this year on 2 October). Because of geometrical considerations, this full moon is not as impressive as its predecessor in terms of the string of long moonlit nights when the moon rises near sunset. The Hunter Moon may have been named because the moonlight may have assisted hunters in their autumnal hunt.
WIND OBSERVATIONS -- For a look at how the horizontal wind direction changes as you go up in the lower troposphere, see the Wednesday optional Supplemental Information on the Ekman spiral.
From the files of the Aviation Weather Center, Kansas City, MO and Intellicast