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WET WEATHER CONTINUES ACROSS SOUTH FLORIDA -- Rainshowers and imbedded thunderstorms continued to produce heavy rainfall accumulation across south Florida on Monday. The large area of rain was found along a trough line that was the remnants of a stationary front. This trough line stretched across south Florida from near Grand Bahama in the Atlantic to the south central Gulf of Mexico. Abundant moisture from the Caribbean was feeding these storms. Several inches of rain had fallen across south Florida by Monday night.
The trough line and the accompanying rains are expected to continue across the Florida Peninsula through Tuesday, with 2 inches of rain forecast through the evening hours. As a result, a flood watch was in effect for essentially all of south Florida located south of Lake Okeechobee.
A STORM SKIRTS THE ATLANTIC SEABOARD -- A relatively strong storm system that developed off the Florida Coast on the weekend continued moving northward over the Gulf Stream on Monday. This system had produced heavy surf conditions along the East Coast. As of Monday night this storm system was situated approximately 400 miles east of Cape May, NJ. Some clouds and light precipitation extended as far northwest as Cape Cod, MA. The storm is forecast to continue moving north toward the Maritimes on Tuesday.
High pressure over New England on Monday morning provided the conditions for radiative cooling. As a result, the minimum temperature at Hartford-Windsor Locks, CT fell to a record-tying 31 degrees.
A COOLING ACROSS THE MIDWEST -- A series of cold fronts moving across the nation's midsection on Monday night was setting the stage for a spell of cool weather by the end of the week. The first cold front stretched from a low pressure system over northern Quebec southwestward across Lake Huron, the Midwest and into the southern Plains before reaching the Texas Panhandle. Temperatures behind this first front were as much as 10 degrees lower than before frontal passage. A second cold front trailing a low in northern Manitoba was the leading edge of a colder air mass located in the western Prairie Provinces. This front curved southward across the Red River Valley separating northwest Minnesota from the eastern Dakotas before turning westward to cross South Dakota and eventually become a stationary front over western Montana.
Some light precipitation was detected across Upstate New York ahead of the first front, while heavier precipitation was found across the Nebraska Panhandle and portions of southeastern Wyoming to the south of the second cold front.
On Tuesday the first cold front should move eastward into the eastern Great Lakes by morning and across New England by evening. Rain is expected across Upstate New York and northern New England. The second cold front is anticipated to push southward and eastward into the western Great Lakes. Rain associated with this front should develop eastward across the Plains, with as much as 0.25 inches expected by late Tuesday.
ABNORMALLY WARM WEATHER ACROSS THE PLAINS -- Unseasonably warm weather was located to the south and east of the first cold front. Afternoon high temperatures from the central Great Lakes to the Southwest were above the long-term average highs for the date, with as much as 20 degree above average readings reported across west Texas and portions of adjoining states. Record high temperatures were either tied or set on Monday afternoon in Texas at Wichita Falls (102 degrees), Midland (101 degrees), Abilene (99 degrees) and Lubbock (99 degrees), in Colorado at Grand Junction (87 degrees) and Colorado Springs (84 degrees), at Fort Smith, AR (93 degrees) and at Winslow, AZ (90 degrees). The highs at Midland and Lubbock were also records for the month of October at these stations.
TEMPERATURE EXTREMES IN THE LOWER 48 -- The lowest temperature on Monday was 24 degrees at Olney, MT, while Monday's highest temperature was 108 degrees at Lake Havasu City, AZ.
ALASKAN WEATHER -- Arctic air remained over a large portion of Alaska as one cold high pressure system was located along the Alcan border and another high pressure center remained over eastern Siberia. However, much of the state remained cloudy, except for some sunny skies found in the interior and the Panhandle. A storm system moving toward the east across the Bering Sea spread clouds and precipitation across western Alaska. The elongated low pressure center was located in the central Bering Sea with an occluded front that stretched eastward into Bristol Bay where a warm front continued eastward across the Alaska Peninsula and Kodiak Island, while a cold front curved south and southwestward across the North Pacific. Rain fell at Bethel, Cold Bay, Seward, King Salmon, Saint Paul and Kodiak. A cold front trailing a low pressure system over the Arctic brought clouds and snow to the Arctic coast, where light snow was reported at Barrow and Wainwright.
The state lowest temperature on Monday morning was 4 degrees below zero at Anaktuvuk Pass. The highest temperature across Alaska as of midafternoon on Monday was 54 degrees at Dutch Harbor.
HAWAIIAN WEATHER -- Light and variable winds continued across the islands on Monday afternoon as a subtropical ridge of high pressure remained weak. A low pressure system located approximately 1000 miles north of Hawaii also contributed to the southeasterly winds and humid conditions. Some afternoon clouds and showers continued. The low is expected to move toward the north-northeast and the ridge should build, thereby permitting a return of light easterly trade winds by midweek.
Ocean swell generated by a storm system located east of New Zealand last Thursday is expected to reach the south facing shores of the Hawaiian Islands by late Tuesday, resulting in surf that could reach 6 feet in height.
EYE ON THE TROPICS -- Hurricane Keith continued to batter Belize and the Mexican states in the Yucatan Peninsula on Monday. Some locations near Belize City received more than 15 inches of rain because of the hurricane's slow movement. Extensive flooding was reported across Belize. As of late Monday night Keith was downgraded to tropical storm status as near surface winds fell to 65 mph, below the 75 mph threshold for hurricane status. At that time, the central eye was approximately 30 miles south-southeast of Chetumal, Mexico, and the system was moving to the north-northwest at 2 mph. The heavy rains will remain a problem across the region even though the intensity of Keith had diminished.
In the eastern North Pacific basin, Tropical Depression 17E formed along the Mexican coast on Monday. As of late Monday night, the system had estimated winds of 30 mph and it was located near Lazaro Cardenas, Mexico moving to the west at 4 mph.
Air temperatures may vary greatly from day to day. Today's afternoon high temperature may be 5 degrees warmer than that experienced on yesterday afternoon, or tomorrow morning's low temperature is expected to be 15 degrees colder than what was recorded this morning. Some places in the country experienced similar changes yesterday as a major storm system affected the temperature patterns in the center of the country. How are these significant changes possible?
Many factors are at work in determining the near-surface air temperature at a given place and time. The daily variation in temperature is driven by the daylight and darkness cycle in solar radiation. Under clear skies, the day's maximum temperature typically occurs within an hour or two after local solar noon. Local noon is that time when the sun at most locations would be directly to the south of you and is at its highest point in the sky for that day. Clear skies will usually cause the daily minimum temperature to occur within an hour of local sunrise. If all other factors were equal, changes in the daily temperature pattern from one day to the next would be small because day to day changes in the incoming solar radiation typically are not large.
Cloud cover could complicate the situation - lowering the afternoon temperatures because of the blocking of at least some of the incoming solar radiation, and reducing the drop in overnight temperatures because the clouds absorb the outgoing thermal radiation from the earth and radiate much of it back to the surface.
A third factor affecting the day to day temperature variations is the role that the general wind flow has upon local temperatures. Many times the observed large swings in temperature from day to day result when warm air from some distant locale replaces the cooler air that has resided in the area. This replacement causes a warming. Conversely, if colder air invades, a noticeable temperature drop results. These examples are termed "warm air advection" and "cold air advection", respectively, and could be more significant than the other two factors identified above. Warm air advection can occur with the passage of a warm front and a warm air mass is ushered into the region. A less dramatic change would occur when the winds turn to blow from a warmer region as a high pressure system pulls away from the region. Conversely, cold air advection would take place after a cold front passed and a cold air mass makes its influence felt. For more details describing how you can use a surface weather map to determine regions of warm or cold air advection, consult DataStreme Activity 4A and Tuesday's optional electronic Supplemental Information .
To be submitted on the lines for Tuesday on the Study Guide, Part B, Applications, Week 4 Chapter Progress Response Form, under section B. Daily Summary.
From the files of the Aviation Weather Center, Kansas City, MO and Intellicast