Clouds, wind and rain conspire to end 2010's longest mild streak

The inexorable seasonal march toward summer is on–but you wouldn’t
know it to step outside Saturday. At best, it’s a “march” which
proceeds in fits and starts–warm one day, chilly the next. The
temperature reduction, powerful 35+ mph gusts and spells of rain
sweeping the Chicago area Saturday may best be characterized as a
“fit”–rather than a “start.”

The past week’s all too brief
three-day excursion into the world of 50 and 60-degree temperatures is
history–for now. Warm-weather enthusiasts should take some solace in
early indications a spell of 60s may return for another comparatively
brief run later next week. Any prospect Saturday’s dreary weather is
headed for the meteorological exit is being dashed by the onset of a
“blocking pattern” across Canada not expected to ease until next week.
Blocking patterns don’t automatically mean all weather movement
screeches to a halt. But they often slow weather’s progression,
allowing systems–like the weekend’s blustery low pressure storm–to
linger.

Rainfall could approach an inch

Rain with
the current storm system arrived into the Chicago area from the
southeast–that’s right, from the southeast–Friday afternoon. That’s
opposite the movement of a majority of weather systems which tend to
arrive from the west or southwest. The storm’s slow movement is to keep
the Chicago area shrouded by clouds and subjected to wind and sporadic
rain or drizzle through the weekend. Precipitation estimates vary–but
average to around 1 inch. It’s the wind which many here may find most
objectionable. Varied pressures between the slow-moving storm downstate
and a sprawling Canadian high to the north will drive the gusty wind
regime. The set-up shows little sign of breaking down. Instead, its
demise is to be a slow one, suggesting its northeast to north winds
could still be with us into Wednesday–even though an injection of
drier air Monday should permit clouds to break and allow passing sun.

West Palm Beach walloped by over 5″ of rain

It
was south and central Florida’s turn for heavy rain Friday. Both coasts
of the often-sunny peninsula were subjected to wind-driven downpours
which totaled a record-breaking (for March 12) 5.28″ at West Palm
Beach, 4.08″ at Tampa, 3.67″ at Ft. Myers and 3.21″ at Vero Beach.
Storm gusts topped 40 mph.

A number of recent computer projections suggest sticking snow not out of the question in Week #2

Temperatures
are projected to rebound–possibly to the 60s–next Thursday and
Friday. But, a suite of longer-range computer models suggests fairly
strong cooling may follow. Projections into the 1-2 week time range
imply the cool-down may be strong enough to allow sticking snow in
sections of the Midwest–possibly not far from Chicago. It’s a
development we’ll monitor.

Sunlight in March

Dear Tom,
I know that days are getting longer, but is it in March that we gain the greatest amount of daylight?

–Pat Roberts, Lockport

Dear Pat,
It certainly is. March leads all months in daylight gain with an increase of 1 hour, 25 minutes during the course of the month. Runner-up April posts an increase of 1 hour, 17 minutes while February ranks third with a 70-minute increase.
When it comes to loss of daylight in the fall, October takes the honors with a decrease of 1 hour, 21 minutes, beating out September by just 1 minute.
On Sunday, when we turn our clocks ahead one hour as daylight saving time begins, the city will record 11 hours, 52 minutes of daylight, with sunrise at 7:04 a.m. and sunset at 6:56 p.m.

Dense fog invading the Chicago area-extends north into Wisconsin

Dense fog advisories have been issued for Lake and Cook counties in northeast Illinois until   4 a.m. Saturday morning. Visabilities are dropping to less than 1/4 mile across much of Chicago late this Friday evening. At 11 pm the visibility at O’Hare was 1/2 mile, while Wheeling and Waukegan reported 1/4 mile.  The dense fog continues north into Wisconsin with much of the eastern portion of that state socked in with near zero visibility.

The fog is expected to improve during the overnight hours as an area of showers and thunderstorms move in from Indiana. As these storm arrive, visibilities should increase as the fog dissipates. 

Caution is advised as the dense fog will hinder driving.