It’s about time! Temperatures are finally responding to the barrage of stronger sunlight which pours down on the area this time of year. March sunlight delivers nearly three and a half times the solar energy of December sun and its impact on the degree of warming which takes place each day can be dramatic. The trick is to get the sun to shine so all that energy can translate into higher temperatures. That’s precisely what happened Thursday.
In a month which has produced 20 percent less sun than typical—39% versus the normal of 49% of Chicago’s possible sun—-the appearance of a full day of uninterrupted sun translated into warming which propelled Chicago area temperatures to a 51-degree high— the warmest reading here in 18 days. And even milder temperatures are on the way Friday when 54-degrees is predicted. Cool easterly “lake breezes” are likely to limit immediate shoreline readings to the low 40s.
But the warmest temperature we’re likely to see in the next 7 days is predicted Saturday, a day which, if meteorological elements fall into place as it appears they may, could host 2013′s second 60-degree daytime high—or a reading very close to 60.
Thursday’s 51-degree high only the second 50 this month; warmest temp in 18 days
Despite Thursday’s 51-degree high—only the 2nd 50 to occur this month and the warmest reading here in 18 days—it was still the 17th day in a row to post a daily temperature deficit. Friday temperatures may actually end up above normal breaking the relentless string of sub-normal temperatures here.
Month ranks 25th coldest of the past 143 Marches
The shortage of sunshine and stubborn and pervasive arctic region warming which has forced chilly air southward into the Lower 48, has produced monthly temperature deficits across virtually all of the Midwest.
Here in Chicago, the month —more than 23-degrees colder than the same period a year ago—ranks 25th coldest of the past 143 years and is running more than 6 degrees below normal.
Warming has melted nearly half the Lower 48′s snow cover since Monday; the weekend storm’s remaining downstate snowpack is disappearing fast
The warming has all but obliterated the bulk of the weekend storm’s snowpack downstate and also slashed the swath of the Lower 48 which sits beneath a cover of snow by 43% since Monday.
The week opened with nearly 49% of the country covered by snow, but by Thursday just 28% of the Lower 48 sat beneath a layer of snow.
In central Illinois, where last weekend’s snowfall reached a foot and a half at some locations, snow depths have crashed during the same period.
Springfield, hit with an 18.5″ accumulation in the Sunday afternoon and nighttime storm, has watched as the 16 inches of snow on the ground as Monday dawned dwindled to just 2 inches by daybreak Thursday.
In St. Louis, the snow cover, once 8 inches, diminished to just 1 inch during the same period. Peoria’s 6-inch early week snow cover has dropped to 0.
Buckling jet stream to send new late season chilly spell plunging south out of Canada for April’s open Monday
The warmth Saturday and seasonable 50 predicted Easter Sunday won’t last. A healthy new outbreak of late season arctic air arrives on gusty northwest winds Sunday night and Monday.
The cold, unstable air predicted to ride northwesterly jet stream winds into the area is likely to produce a fair amount of cloud cover Monday which, in turn, will block warming sunlight. Together—the clouds and lack of sunlight —could limit Monday highs to the upper 30s or low 40s—making the White Sox home opener a chilly affair. The atmosphere is projected to grow unstable enough that at least some spells of flurries are possible Monday and perhaps Tuesday as well.