by Meteorologist Tom Skilling
Tuesday's comparatively mild open gives way to powerful northwest winds which will send Chicago area temperatures plunging into the 20s by nightfall, the first of two cold blasts predicted this week. The second and strongest of the week's cold surges takes hold Thursday, when daytime temperatures are to hold in the teens for the first time this winter.
Tuesday's wind-driven temperature pullback supplants Monday's brief, snow-melting temperature surge to 45-degrees--the area's mildest reading in 5 days.
Monday's "warm-up" took a big bite out of the area's heaviest winter snowpack to date, reducing the depth of the snow on the ground from 6 inches last Thursday to just an inch Monday morning. The melt-off continued Monday as rain fell across the city and by evening less than an inch of snow remained.
As snow was melting here, temperatures downstate surged to 68-degrees at St. Louis--28-degrees above normal--while nearby Columbia, Missouri recorded a record high of 70. The year's first tornado watch was hoisted by NOAA's Storm Prediction Center late Monday night in that warm air mass.
A switch from rain to snow, forecast to get underway in Chicago's northwest suburbs Tuesday morning, will reach the city by lunchtime and proceed southeastward across northwest Indiana Tuesday afternoon. Accumulations of 1 to 2 inches of new snow are a good bet. Local 2 to 3 inch totals may occur northwest of Chicago toward Rockford and into southern Wisconsin while the southern suburbs may see snow totals in the half inch to inch range.
Season's coldest air yet hits Thursday/Thursday night behind brief burst of snow or flurries Wednesday night
Late Tuesday's chill is just the beginning. A second, more potent cold punch arrives Thursday behind brief Wednesday night snows. That chill is to emanate from a huge reservoir of frigid air covering much of Canada. Wind chills may dip to 20 to 30-below as far south as Minnesota and northern Wisconsin--and could flirt with zero here in the Chicago area as Thursday dawns.
Significant changes in the pattern this weekend into next week suggest the flow of arctic air will cease and a period of above normal overall temperatures is on the way.
Second round of accumulating snow looms Friday afternoon and night ahead of the warmup
Before weekend warming commences, a vigorous eastbound system--an offshoot of the parade of powerful Pacific storms pounding the Pacific Northwest and northern Rockies--appears on a favorable track to produce the week's second band of accumulating snow which could affect Chicago Friday afternoon into Friday night.
Despite recent chill, winter 2011-12 meek compared to its past four predecessors; temps up 12-degrees, snowfall just a third of last winter's
Despite the winter's coldest temperatures yet this past weekend--including lows of 8 and 5-above on Saturday and Sunday--only 6 days since the Dec. 1 start of meteorological winter have produced below normal temperatures. This winter's daily temperatures have posted surpluses 87 percent of the time and the season's average temperature of 33.8-degrees is 11.8-degrees warmer than the same period a year ago.
The mild temperatures have reduced Chicago's winter snowfall to just 7 inches--less than a third of last season's 22.8 inches by now.
Pineapple Express-type pattern to hurl storms into the Pacific Northwest/northern Rockies over the coming week; rainfall could top one foot in some sections while big snows threaten farther north
A Pineapple Express type pattern, so-named because it consists of a stream of moisture which originates from the south Pacific near Hawaii into the country's northwest coast as well as western Canada, is threatening to produce a real soaking and some huge snow accumulations over the Pacific Northwest.
Seattle is threatened by significant snowfall the next few days and some western mountain ranges could see more than 5 feet of snow by week's end.
Rainfall projections of as much as 15 inches of rain have been issued the next five days over coastal and mountain-upslope areas of Oregon and northern California.
Huge waves are to pound the coast line, some exceeding 30 feet in height.
Powerful west to east steering winds aloft to limit length of arctic incursions into U.S. in 7 to 14 day time range; models forecasting big U.S. temperature surpluses
The same upper level steering winds guiding these storms into the Northwest are to send comparatively mild maritime air surging across a huge swath of the Lower 48 and southern Canada. While bitterly cold air--at times as much as 27 or more degrees below normal--takes up residence next week across Alaska and the Yukon--much of the remainder of the continent is in for unseasonably mild temperatures.
Chicagoans can expect 40s to sweep into the area Sunday and Monday. And a consensus of temperature predictions off the National Weather Service's GFS and the European Center's ECMWF models produces a prediction that the next 5 days will average nearly normal while the 6 to 10 day period is to run 9.6-degrees above normal and the 11 to 15 day period may see readings averaging 6.7-degrees above normal.
Tuesday's comparatively mild open gives way to powerful northwest winds which will send Chicago area temperatures plunging into the 20s by nightfall, the first of two cold blasts predicted this week. The second and strongest of the week's cold surges takes hold Thursday, when daytime temperatures are to hold in the teens for the first time this winter.
Tuesday's wind-driven temperature pullback supplants Monday's brief, snow-melting temperature surge to 45-degrees--the area's mildest reading in 5 days.
Monday's "warm-up" took a big bite out of the area's heaviest winter snowpack to date, reducing the depth of the snow on the ground from 6 inches last Thursday to just an inch Monday morning. The melt-off continued Monday as rain fell across the city and by evening less than an inch of snow remained.
As snow was melting here, temperatures downstate surged to 68-degrees at St. Louis--28-degrees above normal--while nearby Columbia, Missouri recorded a record high of 70. The year's first tornado watch was hoisted by NOAA's Storm Prediction Center late Monday night in that warm air mass.
A switch from rain to snow, forecast to get underway in Chicago's northwest suburbs Tuesday morning, will reach the city by lunchtime and proceed southeastward across northwest Indiana Tuesday afternoon. Accumulations of 1 to 2 inches of new snow are a good bet. Local 2 to 3 inch totals may occur northwest of Chicago toward Rockford and into southern Wisconsin while the southern suburbs may see snow totals in the half inch to inch range.
Season's coldest air yet hits Thursday/Thursday night behind brief burst of snow or flurries Wednesday night
Late Tuesday's chill is just the beginning. A second, more potent cold punch arrives Thursday behind brief Wednesday night snows. That chill is to emanate from a huge reservoir of frigid air covering much of Canada. Wind chills may dip to 20 to 30-below as far south as Minnesota and northern Wisconsin--and could flirt with zero here in the Chicago area as Thursday dawns.
Significant changes in the pattern this weekend into next week suggest the flow of arctic air will cease and a period of above normal overall temperatures is on the way.
Second round of accumulating snow looms Friday afternoon and night ahead of the warmup
Before weekend warming commences, a vigorous eastbound system--an offshoot of the parade of powerful Pacific storms pounding the Pacific Northwest and northern Rockies--appears on a favorable track to produce the week's second band of accumulating snow which could affect Chicago Friday afternoon into Friday night.
Despite recent chill, winter 2011-12 meek compared to its past four predecessors; temps up 12-degrees, snowfall just a third of last winter's
Despite the winter's coldest temperatures yet this past weekend--including lows of 8 and 5-above on Saturday and Sunday--only 6 days since the Dec. 1 start of meteorological winter have produced below normal temperatures. This winter's daily temperatures have posted surpluses 87 percent of the time and the season's average temperature of 33.8-degrees is 11.8-degrees warmer than the same period a year ago.
The mild temperatures have reduced Chicago's winter snowfall to just 7 inches--less than a third of last season's 22.8 inches by now.
Pineapple Express-type pattern to hurl storms into the Pacific Northwest/northern Rockies over the coming week; rainfall could top one foot in some sections while big snows threaten farther north
A Pineapple Express type pattern, so-named because it consists of a stream of moisture which originates from the south Pacific near Hawaii into the country's northwest coast as well as western Canada, is threatening to produce a real soaking and some huge snow accumulations over the Pacific Northwest.
Seattle is threatened by significant snowfall the next few days and some western mountain ranges could see more than 5 feet of snow by week's end.
Rainfall projections of as much as 15 inches of rain have been issued the next five days over coastal and mountain-upslope areas of Oregon and northern California.
Huge waves are to pound the coast line, some exceeding 30 feet in height.
Powerful west to east steering winds aloft to limit length of arctic incursions into U.S. in 7 to 14 day time range; models forecasting big U.S. temperature surpluses
The same upper level steering winds guiding these storms into the Northwest are to send comparatively mild maritime air surging across a huge swath of the Lower 48 and southern Canada. While bitterly cold air--at times as much as 27 or more degrees below normal--takes up residence next week across Alaska and the Yukon--much of the remainder of the continent is in for unseasonably mild temperatures.
Chicagoans can expect 40s to sweep into the area Sunday and Monday. And a consensus of temperature predictions off the National Weather Service's GFS and the European Center's ECMWF models produces a prediction that the next 5 days will average nearly normal while the 6 to 10 day period is to run 9.6-degrees above normal and the 11 to 15 day period may see readings averaging 6.7-degrees above normal.
