Saturday, November 29, 2008
First snow
Well here it is November 29, 2008. Our first significant snowfall of the season is upon us. After last weeks Winter Weather Preparedness week, our first winter weather advisory has been issued for the Chicago area. A general 3-6 inches of snow is expected by Monday morning. With tomorrow and Monday expected to be the biggest travel days, hundreds of cancellations and delays are anticipated affecting hundreds acroos the country. Behind the system, temps will fall into the mid 20s by Monday evening with low tuesdy morning in the upper teens. With a brisk NW wind 15-20 mph wind chills will feel like the lower teens. Blowing and drifting snow will also be a concern.
Wednesday, November 26, 2008
Chicago stats for Thanksgiving
Below is a frequency distribution of high and low temperatures in Chicago. Note: The temperatures are a 136 yr data set from 1873 to last year (2007).
The most frequent range of high temperatures on Thanksgiving is in between 40 and 49 degrees. The highest temperature recorded on Thanksgiving is 69 degrees set on November 24th, 1966. The coldest high temperature on Thanksgiving is 14 degrees which occurred on November 27th, 1930 which also is the last time we were below 20 degrees. Because Thanksgiving doesn’t always occur on the same day, there is really no normal high, but the normals for around this time of year is in lower 40s (Highs) and the upper 20s (Lows). Last year, the high temperature was 33 degrees which is in the 2nd most common range of high temperatures. This Thanksgiving is forecasted to fall in the 40-49 range (the most frequent range).
The most frequent range of low temperatures on Thanksgiving is in between 30 and 39 degrees. The lowest temperature recorded on Thanksgiving is -1 which occurred on November 23rd, 1950 which happens to be the only time we had a temp. below zero and the last time we dropped below 10 degrees. The highest low temperature for Thanksgiving was 57 degrees in 1896. The last time our low temperature was over 50 degrees was November 24, 1966 with a low temp of 54. Last year, the low temperature was 25 degrees, which is in the 2nd most common range of low temperatures. This year, Chicago is expected to fall in the 30-39 category (also the most frequent).
The most frequent range of high temperatures on Thanksgiving is in between 40 and 49 degrees. The highest temperature recorded on Thanksgiving is 69 degrees set on November 24th, 1966. The coldest high temperature on Thanksgiving is 14 degrees which occurred on November 27th, 1930 which also is the last time we were below 20 degrees. Because Thanksgiving doesn’t always occur on the same day, there is really no normal high, but the normals for around this time of year is in lower 40s (Highs) and the upper 20s (Lows). Last year, the high temperature was 33 degrees which is in the 2nd most common range of high temperatures. This Thanksgiving is forecasted to fall in the 40-49 range (the most frequent range).
The most frequent range of low temperatures on Thanksgiving is in between 30 and 39 degrees. The lowest temperature recorded on Thanksgiving is -1 which occurred on November 23rd, 1950 which happens to be the only time we had a temp. below zero and the last time we dropped below 10 degrees. The highest low temperature for Thanksgiving was 57 degrees in 1896. The last time our low temperature was over 50 degrees was November 24, 1966 with a low temp of 54. Last year, the low temperature was 25 degrees, which is in the 2nd most common range of low temperatures. This year, Chicago is expected to fall in the 30-39 category (also the most frequent).
Monday, November 17, 2008
**Winter Weather Preparedness Week!!!**
This week November 16 thru November 22nd is Winter weather preparedness week for Illinois and Indiana. Throughout this week as we get ready to prepare for the winter season, I will supply you with winter weather facts, tips, and terms.
Winter Weather Definitions:
Winter Storm Watch - Conditions are favorable for hazardous winter weather conditions including heavy snow, blizzard conditions, or significant accumulations of freezing rain or sleet. These watches are usually issued 12 to 36 hours in advance of the event.
Winter Storm Warning - Hazardous winter weather conditions that pose a threat to life and/or property are occurring, imminent or likely. The generic term, winter storm warning, is used for heavy snow of 6 inches or greater, heavy sleet of half inch or more, or a combination of two or more of the following winter weather events; heavy snow, freezing rain, sleet and strong winds. The following event-specific warnings are issued for a single weather hazard:
• Blizzard Warning - Sustained winds or frequent gusts of 35 mph or greater, considerable falling and/or blowing snow reducing visibility frequently to 1/4 mile or less for a period of three hours or more. There are no temperature criteria in the definition of a blizzard but freezing temperatures and 35 mph winds will create single digit wind chills.
• Lake Effect Snow Warning - Lake effect snowfall of 6 inches or more in 12 hours or less, or 8 inches or more in 24 hours or less.
• Ice Storm Warning - Accumulations of 1/4 inch or more of freezing rain.
Winter Weather Advisory - Hazardous winter weather conditions are occurring, imminent or likely. Conditions will cause a significant inconvenience and if caution is not exercised, will result in a potential threat to life and/or property. The generic term, winter weather advisory, is used for a combination of two or more of the following events; snow, freezing rain or drizzle, sleet, blowing snow.
Wind Chill Warning - Extreme wind chills of -30oF or colder.
A Wind Chill Warning is issued when the wind chill will be less than or equal to -30oF AND winds greater than or equal to 10 mph.
Wind Chill Advisory - Dangerous wind chills of -20oF to -30oF.
A Wind Chill Advisory will be issued when the wind chill is less than or equal to -20oF AND the winds are greater than or equal to 10 mph.
Winter Weather Definitions:
Winter Storm Watch - Conditions are favorable for hazardous winter weather conditions including heavy snow, blizzard conditions, or significant accumulations of freezing rain or sleet. These watches are usually issued 12 to 36 hours in advance of the event.
Winter Storm Warning - Hazardous winter weather conditions that pose a threat to life and/or property are occurring, imminent or likely. The generic term, winter storm warning, is used for heavy snow of 6 inches or greater, heavy sleet of half inch or more, or a combination of two or more of the following winter weather events; heavy snow, freezing rain, sleet and strong winds. The following event-specific warnings are issued for a single weather hazard:
• Blizzard Warning - Sustained winds or frequent gusts of 35 mph or greater, considerable falling and/or blowing snow reducing visibility frequently to 1/4 mile or less for a period of three hours or more. There are no temperature criteria in the definition of a blizzard but freezing temperatures and 35 mph winds will create single digit wind chills.
• Lake Effect Snow Warning - Lake effect snowfall of 6 inches or more in 12 hours or less, or 8 inches or more in 24 hours or less.
• Ice Storm Warning - Accumulations of 1/4 inch or more of freezing rain.
Winter Weather Advisory - Hazardous winter weather conditions are occurring, imminent or likely. Conditions will cause a significant inconvenience and if caution is not exercised, will result in a potential threat to life and/or property. The generic term, winter weather advisory, is used for a combination of two or more of the following events; snow, freezing rain or drizzle, sleet, blowing snow.
Wind Chill Warning - Extreme wind chills of -30oF or colder.
A Wind Chill Warning is issued when the wind chill will be less than or equal to -30oF AND winds greater than or equal to 10 mph.
Wind Chill Advisory - Dangerous wind chills of -20oF to -30oF.
A Wind Chill Advisory will be issued when the wind chill is less than or equal to -20oF AND the winds are greater than or equal to 10 mph.
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