During the late winter and early spring, the reservoir of cold water known as the Great Lakes can cool surrounding areas considerably! Today, we shot into the 70s while much the big cities and suburbs to our east saw 60s. A northeasterly wind in March and April can bring our temperatures down by as much as twenty degrees. However, with water temperatures rising into the 50s now, the strength of that cooling will become confined to areas closer to the lakeshore. Still, as we know, that “cooler by the lake” phrase will be used quite a bit by our Meteorologist friends in Milwaukee and Chicago. However, in a few weeks, it will be pretty hard to get that cooling this far inland.

More importantly, will be the cold bursts of air from Canada…and there’s one coming for the weekend. Models are consistent in bringing a cold front through the area Saturday. Depending on the strength of the airmass behind it, temperatures may only top out in the lower 50s by Sunday…a far cry from this past weekend.

However, don’t fret. This is way out on Day-6 of our 7 Day Outlook. We could see this cold air modify a bit and even delay, which could cause us to bump up those forecast highs.

Posted under cold blast, weather geek

Saturday marked just the fourth time where temperatures climbed to 70 degrees or more in Rockford.  If you were like me, you probably enjoyed it!  The mild weather has been lacking across the Stateline for much of the year.  When reviewing all 124 days of 2013 (January 1 through May 4), just 15 days have had high temperatures at or above 60 degrees! That’s only 12 percent of all days so far. That figure lowers to just 3 percent, when reviewing days of 70 degrees or greater!

While only one day rose above 60 degrees in January, no days had high temperatures in the 60s (or higher) in February and March!  April saw ten days with high temperatures in the 60s. But it wasn’t until April 29 when Rockford broke the 70 degree mark (75 to be exact)—nearly one month later than the average first 70-degree day!

The forecast for the first full week of May will bring an end to the mild weather drought, so to speak, with at least 5 days at or above 70 degrees! -Joe

Posted under 13 Climate Authority, statistics, weather, weather geek

Have you been sniffling and sneezing? Tis the season for allergies and the weather has a lot to do with how you may feel. This week, we were invited to the laboratory at the Winnebago County Health Department to see how the pollen is counted. On the roof is a machine, dubbed the “RotoRod” spins a sticky piece of plastic for one minute, every ten minutes, for 24 hours. Some of the pollen that floats through the air sticks to the plastic. Each morning, scientists in the lab must climb a ladder to the roof of the building and collect the sample.

Larry Swacina, Director of Environmental Health says “You don’t realize there’s small little world of this entire world of this small little particles of living things. it’s just fascinating to look under the microscope and see all of that.”

The sample is brought back to the lab and inserted into a microscope where certain types of pollen are identified. For instance, pine tree pollen has little wings which allows it to ride the wind, traveling longer distances. Ragweed pollen is spiky, which causes big problems for sufferers.

Once each pollen is identified, the sample is analyzed which allows the lab tech to determine how much grains of pollen is in a typical cubic foot of air.

Swacina says it’s important to sample each day’s pollen because of our aging population as he believes more people are developing allergy or asthma symptoms.

You can get each day’s Allergy Report on 13News at Noon and 5pm each weekday.

Posted under weather, weather geek

Today’s 87 degree high temperature in Rockford was just four degrees off the record high for the date! It’s hard to forget the heat of 2012, but to put this warmth in perspective, check out the amount of time that has elapsed since September 12th when the mercury soared to 89 degrees! Almost 20 million seconds ago.

Wednesday will be warm once again, although likely a few degrees cooler. Look for highs in the middle 80s once again before a much cooler weather pattern takes hold from Thursday on. -Eric

Posted under weather geek

We have had some serious flooding in the past few weeks. But if I saw this, I’d be running away! What do you think? -Eric

Posted under news, weather geek

April 14, 2013 High Temps

An interesting scenario was observed on Sunday. A warm front traveled north during the late morning hours and set up shop along the Illinois-Wisconsin border. North of the warm front, the wind blew out of the east.  The cool water temperatures of Lake Michigan helped to moderate the air mass and kept a chill in the air. As a result, much of our southern Wisconsin counties had temperatures stall in the upper 40s and lower 50s.

South of the warm front was a different story! With a south to southeast wind, many communities along and south of Interstate 88 and west of Interstate 39 climbed into the lower 70s! Freeport, Rochelle, DeKalb & Galena all recorded their first 70-degree temperatures of the year.

Temperature vs. Wind Direction

The Rockford & Belvidere area was in somewhat of a transition zone.  The warm front lifted north of the metro area around 2pm and allowed temperatures to climb into the upper 60s. However, around 4:30pm the front sagged to the south. As a result, the wind direction shifted from the mild southerly breeze to the cool easterly breeze and temperatures fell into the upper 50s around dinnertime.  Not long after sunset, however, the front moved back north of the metro area.  Even without the help of the sun, the warm air advected from the south and temperatures climbed back into the middle 60s!

-Joe

Posted under weather, weather geek, Wind

April has been quite a rainy month so far with 1.75 inches falling at the Chicago/Rockford Int’l Airport through 3pm Wednesday. That amount is 160% of normal! While 2/3 of an inch of rain falling as a surplus is a good thing to bring our drought to an end, the forecast is not.

The forecast from the National Weather Service’s GFS model shows 2.41″ of rainfall coming in the next 16 days. That amount is more than we should receive in a typical April, 135% of normal.

Of concern is this pattern of repeated rainfall. With our rivers now flooding in Northern Illinois and Southern Wisconsin, we need this pattern to change in order to get the river levels to level off.

Meteorologists refer to this type of situation as ”high evaporative feedback.” Because our ground is saturated, it will lead to increased evaporation in the days and weeks to come. This will cause storm systems to be wetter than normal, with our models possibly underdoing the rain forecast for the next few weeks. Signals show this pattern will persist for a few weeks, possibly well into May.

With a barrage of storm systems coming through the center part of the United States over the next 1-2 weeks, prepare for rising river levels and increased flooding. Below are a few of the river gauges from this afternoon. You can see all of the levels on the National Weather Service’s Rivers and Lakes Page here.  

Posted under climate/climate change, flooding, rain, record weather, safety, science, weather geek

Occasionally, you’ll hear Meteorologists use the terms “Surface-Based Storms” and “Elevated Storms.” But do you know what the difference is?

Typically, the worst thunderstorms are surface-based. That means they are utilizing the instability of the whole vertical profile. In other words, unstable air is present from the ground, all the way through the thunderstorm. This usually occurs on warm, muggy days when a cold front approaches.

But today we had strong thunderstorms with temperatures in the 40s! Hardly warm and muggy. A stationary front currently lies to our south. A northeasterly wind is pulling in chilly marine air off of Lake Michigan. This airmass goes south to the I-80 corridor. South of the front, temperatures are in the 70s and it is indeed muggy! 

So, why did we have thunderstorms if temperatures were in the 40s and our airmass was stable? You must think of fronts in three dimensions even though they are plotted red and blue in just two dimensions. Picture this! The stationary front acts as a wedge in the atmosphere. While the cold, stable atmosphere exists here at the surface, the warm unstable air over-runs the cold air by lifting over the front from the south. This rising air produces thunderstorms even though the instability isn’t seen here at the surface.

Typically, elevated thunderstorms don’t turn severe. However, because of the cold air in the lower levels, they can and often produce hail (because the hail doesn’t melt quickly as it falls through the colder air). We’ve uploaded some pictures and video of today’s hail onto the 13 Weather Authority Facebook Page. -Eric

Posted under weather geek

A few waves of low pressure will induce light rain and snow showers on Friday. The higher likelihood will be during the afternoon and evening with most emphasis coming for areas into South Central Wisconsin. Precipitation amounts will be light, but some slick spots are anticipated with cooler surface temperatures over the Badger State.

That system will work east Saturday giving us some limited sunshine on St. Patrick’s Day. But by Monday, all bets are all off with respect to concrete solutions on our next system. In simpler terms, there isn’t any consensus in the models yet!

Scenario #1 has two distinct areas of low pressure. One comes close enough to our south to warrant small chances for rain. The main snowmaker stays into Minnesota and Central/Northern Wisconsin. Typically, unphased systems like these tend to be weaker…producing lighter amounts of precipitation. This scenario is the preferred model now (and the reasoning behind me continuing 50% chances for a light rain/snow mix Monday into early Tuesday.

Scenario #2 is plausible and would put down accumulating snow for far Northern Illinois and South Central Wisconsin. If the two low pressure systems end up phasing (combining into one), the result will be a deeper pressure and more available lifting needed to produce precip! This one is still an outlier, but the energy is certainly there off the Pacific Northwest right now. As the system comes into Washington and Oregon, the precipitation, humidity, and wind will be put into the models making them more accurate in the next 12-24 hours. -Eric

Posted under snow, weather geek

Today, March 11th, marks the two year anniversary of the worst earthquake and worst tsunami to ever impact Japan. The earthquake occurred 43 miles of the northeast coast of Japan and was 20 miles deep. This produced a 133ft tsunami that traveled 6 miles inland. Monumental property damage was sustained from both the quake and the tsunami, with thousands of lives lost. Despite Japan’s amazing response to the detection of the earthquake with prompted a tsunami alert live on TV within minutes of the quake, given the short distance it still wasn’t enough time. Here is a look at the tsunami alert which had estimated wave heights on screen within minutes of the first tremor. -Greg http://www.youtube.com/watch?v=24KfBwkMw_M

Posted under earthquake/tsunami, science, weather geek