Tuesday, December 23, 2008

Christmas facts


This dataset shows that the most frequent range of high temperatures on Christmas is in between 30 and 39 degrees. The normal high for Christmas at Chicago is 32 degrees, which falls in the most frequent range. The highest temperature recorded on Christmas is 64 degrees set in 1982. The coldest high temperature on Christmas is -5 degrees which occurred in 1983. Last year, the high temperature was 42 degrees, which is in the 3rd most common range of high temperatures.



This dataset shows that the most frequent range of low temperatures on Christmas is in between 20 and 29 degrees. The normal low temperature on Christmas in Chicago is 17 degrees. The lowest temperature recorded on Christmas is -17 degrees which occurred in 1983. The highest low temperature for Christmas was 46 degrees in 1936. Last year, the low temperature was 21 degrees, which is in the most common range of low temperatures.


Thursday, December 18, 2008

A Major Winter Storm on the way



Nam 12Z 850mb heights, temp. and wind

Nam 12Z Precipitation (by midnight), 850mb temps. and MSLP




After dumping a record 3-6 inches in Las Vegas yesterday, a major winter storm with snow, ice and thunder is on the way. They say what happens in Las Vegas stays in Las Vegas, but unfortunately this storm is headed east bound and we are right in its track. Major forecast challenges continues as whether we will see a major snow storm or a major ice storm. Either way its going to be a mess especially for Friday's morning commute. It seems the axis of major snow/ice is along the I80 corridor. North of I80 will see more snow than frezing rain. South will see more freezing rain than snow. A Winter storm warning has been posted for the Chicagoland area. However, our neighbors just to our south in Kankakee are under an Ice storm warning. Upwards to 8-14 inches is expected along the Illinois/Wisconsin border. 5-9 for the city and west suburbs, 3-8 for the south suburbs (south of I80 3-6 inches), and 0-3 inches Kankakee and south where ice storm warnings are posted where they could see ice accumulations exceed 0.5 inches. The line of heavy snow and ice will be very sharp. The energy from this system will have enough for some convection meaning thunder snow/freezing rain. 1-2 inch per hour snow rates will fall overnight. This is all due the surfacebeing below 32 degree farenheit. This storm system will provide winds fron the south to warm the mid levels of the atmosphere to above freezing. This setup is for a classic freezing rain/ice storm event. The further south the more warm air advection. This is why there is an ice storm warnign for the counties south of us. Now, there is great concern that the towns along, just north and just south of I80 could see an overlapp of snow and ice. This means that there could be ice accumulations of 0.25-0.5 inches then snow accumulations of 3-8 inches on top of that.

Friday, December 12, 2008

2008; Chicago's 2nd wettest year.







After a record breaking September that totaled 13.63 inches of rain for the month, a record single day rainfall total of 6.64 inches on from September 13 to September 14, December 9th with precip of nearly an inch and a half (1.47") pushed us into the second wettest year on record. The wettest year on record was set in 1983 with 49.35 inches. So far this year (our 2nd wettest year) we have 47.11. You have to think with 3 weeks in December still left that number likely will increase.

Below is a list of the top 10 wettest years!

Rank Year Precipitation
1 1983 49.35
2 2008 47.11
3 1970 46.09
4 1954 45.92
5 1883 45.86
6 2001 45.77
7 1993 44.90
8 1982 44.68
9 1885 44.37
10 1957 44.29