Cold Front Coming At Wrong Time for Severe Weather

A cold front will move through the stateline overnight with showers and perhaps a rumble of thunder. But the severe weather they had north of us into central Wisconsin won't hold-together when the front moves through here. (In fact, the severe weather is already ending as of this writing.) If this cold front were coming through during the peak heating of the afternoon, severe weather would be more of a concern. But since it's coming through overnight when the atmosphere is more stable, we'll probably just see some showers and a few rumbles of thunder. (Also, we don't have a lot of moisture at the surface to fuel severe storms.)

By the way, that severe weather in central Wisconsin really was! A tornado touched down in Winnebago County (which is near Osh Kosh), and there were funnel cloud sightings south and east of Green Bay. And strong winds in Waupaca downed a tree.  --TS

Few rumbles to the north

Our weather pattern remains fairly quiet, but active for some across the US.  The jetstream remains in more of a zonal flow with storm systems tracking across much of the northern tiers of the US.  Strong winds in the jetstream will push a low pressure system through the northern Plains and into the northern Great Lakes by this afternoon.  As it does, a warm front will continue to lift off to the north through the afternoon with a trailing cold front sweeping through later this evening and overnight.  A few showers/rumble of thunder may be possible through the night before the front passes Wednesday morning.  Stronger storms will be likely into north-central Wisconsin and back through Iowa closer to the main area of low pressure.  Daytime heating and moderate instability will allow some of the storms to produce gusty winds and hail through the afternoon hours. 

Yet Another Dry Month

All four months of 2010 have been drier than normal in the Rockford area. We've seen 5.84" of precipitation (including melted snow) so far this year, which is 3.30" below our normal-to-date value of 9.14". April continued along this same trend-line of below normal precipitation. We had 2.89" of rain in April 2010... nearly 3/4 inch below our average value of 3.62". Although the warm, dry weather might feel nice, it's obviously bad news for farmers and for fire danger. There is hope for rainfall this coming week with chances of rain in the forecast for Wednesday, Friday, and Saturday.  --TS

A couple rumbles here and there

With a weak disturbance passing through this afternoon, there will be just enough instability to get an isolated thunderstorm during the afternoon/early evening hours.  The main threat for any severe weather looks to remain east and south, but a thunderstorm or two can't be ruled out across the Stateline.  Once the sun sets, any storm activity should diminish and leave partly cloudy skies overnight.

Fourth Warmest April

If you thought it was a little extra warm during the month of April, you weren't alone!  The average montly temperature for Rockford was 54.8°, making it the fourth warmest April on record!  Records date back to July 1906.  Looking back at the last ten years, April 1915 holds the record for the warmest average temperature of 56.3°.  So, what does this hold for the upcoming summer.  According to the Climate Prediction Center above normal temperatures are possible for parts of the Western US, Alaska and parts of the Southeast.  Below normal temperatures are possible for portions of the Great Plains while equal chances for above or below normal temperatures are possible for the Great Lakes.

A Little Cooler Monday

A front has been pushing across the upper midwest on Sunday. By Sunday evening it was approaching the Stateline, and was generating showers, and some thunderstorms over eastern Iowa. Those storms produced some quarter inch hail just west of the Mississippi River. By the time the precipitation reached northern central Illinois it dissipated into light rain. It will end by 1 am. With relatively cold unstable air aloft, and a continuing southwest upper air flow, showers and thunderstorms will pop on Monday afternoon.  They will end quickly as the air stabilizes in the evening.  Warmer air will move in under mostly sunny skies on Tuesday boosting temperatures into the middle  70's by late afternoon.  A series of systems moving across the midwest from Wednesday through Friday with generate several periods of showers and thunderstorms.  Some fairly significant amount of more than 1" may add up by Friday night.  Progressively colder air will bring a noticable cooling trend to the area  by late week, and into the early part of next weekend.
By Meteorologist
Eric Nefstead

Stalled System Tonight...Sunday Afternoon Looks Good

The cold front that generated severe weather on Friday afternoon, and evening has pretty much stalled out this evening.  It stretches from a vertically stacked large upper low over Lake Winnipeg in Manitoba Provience, Canada across Lake Superior, western lower Michigan, southwest to near St. Louis, to southwest Arkansas, to a surface low over Texarkana, and then southwest to the lower Rio Grande Valley.  The front pretty much parallels the upper jet stream.  A mid level disturbance over Texas will get caught up in the northeast flow overnight, and enhance the surface low as it moves across Arkansas and Missouri through east central Illinois by morning.  A band of precipitation has developed in association with this system from Oklahoma, across Missouri, and western Illinois into the north central Illinois area.  Within that band, an area of thunderstorms has developed from extreme northeastern Oklahoma though Missouri to just south west of Quincy, Illinois.  As the entire system moves northeast tonight, enhanced by a 50 knot low level jet, precipitation will overspread the entire Stateline region by late evening.  Conditions appear to be too stable in this area to be able to  to support any thunderstorm activity.  It looks as if any thunderstorms that do occur, will be well off to our southeast.  Rain will be likely from late evening until 4 or 5 am in the morning.  Right now it appears as if it will be mostly light rain, but totals by morning may be a quarter of an inch in some areas.  The rain will scatter on out during the early daylight hours on Sunday, and should be all finished by late morning leaving the day partly sunny with warm afternoon temperatures reaching the low 70's once again.  The large upper low over Manitoba will move slowly into western Ontario on Sunday, and spin a trough of low pressure southeast across the northern plains reaching the Stateline overnight on Sunday night.  Although, this does not appear to be a moisture rich environment, it does look to be quite unstable with some very cold air aloft, so, again showers will probably develop overnight on Sunday with even the possibliity of some thunderstorms over southern Wisconsin.  Any scattered light showers remaining on Monday will not amount to much.  A warm front will push back northward  across the area on Tuesday taking temps back into the low 70's again. No precipitation is expected because of limited moisture availability.  Another front will move through the area on Wednesday with very little affect on the weather.  That front will stall out near the Ohio River Valley on Thursday as the upper flow becomes more westerly, and disturbances moving from west to east across the plains to the north of the front cause showers and thunderstorms to break out in our area from Thursday into Friday.  A push of colder air from Canada will end the precipitation on Friday night. In fact, it may be cold enough Friday night for some patchy frost over parts of southern Wisconsin, with low temperatures below 40 degrees.  Next weekend looks like it will be dry at this time.
By Meteorologist
Eric Nefstead