• http://cimss.ssec.wisc.edu/goes/blog/archives/930
• http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1058&tstamp=200809

www.mc200.com

As well as moving, I’ve been upgrading my computer systems and started writing more of the code for the website backend.  Some of that is stuff that you will never see, like a paging interface to contact our local RACES paging systems.  However (just to prove that I have been doing something), I will show you my upgraded computer and net control setup here at home.  Enjoy!

Overview: 

Desks Detail:    

Microphone, Audio Rack, & Radio Control Head:     

The tornado was rated EF3 on the Enhanced Fujita Scale with maximum winds of 136-165 MPH.  The tornado had a path length of 13.2 miles and a maximum width of around 100 yards.  The tornado started at 3:30 PM CST about 1.2 miles north of Poplar Grove in Boone County and ended at 3:48 PM CST about 3.2 miles north northeast of Harvard in McHenry County.  There were four injuries in Boone County and one in McHenry County.  Included is a path map.

The survey’s for the two tornadoes that occurred in Kenosha County WI will be posted here once the NWS in Milwaukee completes their official survey.  Their preliminary survey, along with some great (well, maybe not so great) pictures of the damage can be found here: http://www.crh.noaa.gov/crnews/display_story.php?wfo=mkx&storyid=12112&source=0

Damaging ice accumulations and strong winds are likely late this afternoon and evening.

Snow and sleet mixed at times with freezing rain will overspread northern Illinois during the early to mid-afternoon.  Precipitation will likely transition to all freezing rain by evening.  Freezing rain will fall rather heavily at times resulting in rapid accumulations of ice on trees, powerlines, and untreated roadways.

Snow and sleet accumulations of 1-3″ are possible this afternoon particularly along the Wisconsin border.  However of much greater concern is expected damaging ice accumulations.  Once the precipitation changes to freezing rain ice accumulations of 1/4″ to 1/2″ will be common with some locations picking up one 1/2″ to 1″ of ice accumulation before temperatures rise above freezing.

Southeast winds will increase to 20-30 MPH with some gusts approaching 40 MPH this evening.  Ice accumulations on trees and powerlines will weigh them down making them extremely vulnerable to the strong winds and likely resulting in power outages.  This is a potentially dangerous situation; the potential exists for widespread and prolonged power outages across the warning area.

It only takes a small amount of ice accumulation on untreated roadways to make travel nearly impossible.  The storm is quickly approaching and preparations for this winter storm should be rushed to completion.  Persons in the warning area should be prepared for the possibility of several days without power.  Stock up on non-perishable foods, flashlights, batteries, and medications in the event of prolonged power outages.

A Winter Storm Warning means significant amounts of snow, sleet, and ice are expected or occurring.  Strong winds are also possible.  This will make travel very hazardous or impossible.

The National Weather Service in Chicago has upgraded the Winter Storm Watch to a Winter Storm Warning, which is in effect from 2:00 PM Saturday to midnight CST Saturday night.

Snow or sleet will develop late Saturday afternoon and increase in intensity by sunset.  Some snow or sleet accumulations are likely before the precipitation changes to freezing rain Saturday evening.  Once the freezing rain begins the potential exists for several hours of freezing rain which could result in ice accumulations in excess of a quarter inch.

Potentially complicating the situation will be the increasingly strong southeast winds late Saturday afternoon and Saturday evening.  Southeast winds will increase to 20-30 MPH with gusts to 40 MPH Saturday evening.  Where ice does accumulate on trees and powerlines, the strong winds will greatly increase the potential for significant tree and powerline damage.

Now is the time to prepare.  Persons in the Warning area should stock up on non-perishable foods, candles, and medications in the event of a prolonged power outage.  Only a small amount of ice accumulation on untreated roadways can make travel nearly impossible.  Do not wait until the storm to begin to prepare!

Temperatures will rise above freezing by late Saturday night with ice melting and improving conditions expected by Sunday morning.

A Winter Storm Warning means significant amounts of snow, sleet, and ice are expected or occurring.  Strong winds are also possible.  The will make travel very hazardous or impossible.

The National Weather Service in Chicago has issued a Winter Storm Watch, which is in effect from noon to midnight Saturday afternoon and evening.

Snow, possibly mixing with sleet is expected to develop across northern Illinois by late Saturday morning.  As warmer air aloft moves north, the precipitation will transition to freezing rain later Saturday afternoon into Saturday evening.  Ice accumulations of 1/4″ with locally higher amounts are possible by Saturday night.  In addition to ice, areas across far northern Illinois near the Wisconsin border may receive 2-4″ of snow.  All precipitation is expected to change over to light rain or drizzle by early Sunday morning.

A Winter Storm Watch means there is a potential for significant snow, sleet, or ice accumulations that may impact travel.  Anyone with travel plans Saturday and Saturday night, including travel through Chicago O’hare and Chicago Midway airports, should continue to monitor the latest forecasts.

… DISCUSSION …

A significant winter storm is expected to affect northern Illinois.  High pressure will move across the region Friday night, bringing a surge of cold air to the Great Lakes region.  Developing low pressure over the Plains will move northeast across the western Great Lakes Saturday night.  As precipitation develops Saturday, it will fall into the colder air at the surface, resulting in a period of freezing rain.  A warm front will lift north early Sunday morning, changing the wintry precipitation to all rain.

A forecast specific to Lake County will be posted here tomorrow, along with maps of precipitation amounts.  Stay tuned for further developments.

Saffir created a scale in 1969 that rates the strength of a hurricane from Categories 1-5.  This scale was then improved and fine tuned by then NHC Director Robert Simpson, becoming known as the Saffir/Simpson scale.  The scale is invaluable in communicating to the public the intensity and danger of approaching hurricanes.

See the original Associated Press article for more details.