In this blog I'll go over what the various winter watches and warnings means, the different types of winter precipitation, and tips to keep you body safe and on the road while your outside exposed to these different winter weather elements.
First I'll go over a list of the all the winter watches and warnings that can be issued. What do they mean? When do they get issued?
FROST ADVISORY
Conditions are or will be favorable for frost to develop. The object or surface where frost will form will occur at 32°F/0°C. However, there is no specific air temperature for frost to form. Generally, frost develops when the air temperature is 32°-36°. Since we've already since our 1st frost (numerous times actually), we won't see this advisory be issued again but the information here is helpful.
FREEZE WATCH
A freeze watch is issued when there is a "CHANCE" for temperatures to be at 32° or below. This can cover a wide length of time and be issued days in advance. Since we've already since our 1st freeze (numerous times actually), we won't see this watch be issued again but the information here is helpful.
FREEZE WARNING
A freeze warning is issued when temperatures are very likely to reach 32° or below or is already occurring. It is not intended to cover a wide-length of time and not issued days in advance. Since we've already since our 1st freeze (numerous times actually), we won't see this warning be issued again but the information here is helpful.
WINTER STORM OUTLOOK
This is a statement issued when there is a chance of a major winter storms from 3 to 5 days in the future. This is meant to assist people with their short or long term plans. However, since the outlook is issued so far in advance, the accuracy of the prediction may be limited.
WINTER WEATHER ADVISORY
This is issued for a combination of snow, sleet, and/or freezing rain. Advisories, in general, are issued for weather conditions that are expected to cause significant inconveniences and may be hazardous, These situations are normally not life threatening if caution is exercised.
WINTER STORM WATCH
This means there is a "CHANCE" for hazardous winter weather due to various elements such as heavy snow, sleet, or ice accumulation from freezing rain. A "WATCH" is issued 12-36 hours before the hazardous winter weather is expected to begin. When the storm becomes imminent, or has a high probability of occurring, the watch will then be upgraded to a "WARNING".
WINTER STORM WARNING
This is issued when hazardous winter weather is occurring, imminent, or likely, and is a threat to life and property. It is not intended to cover a wide-length of time and not issued days in advance. It can be issued up to 12 hours in advance. However, once issued and will remain in effect until storm weakens and is no longer a threat.
WINTER STORM WARNING FOR SEVERE ICING
This can be issued when there is heavy accumulation of ice due to freezing rain that will down trees and power lines. Electricity, or telephone communications, may be out for a long period of time. Roads may become impassable for most vehicles.
BLIZZARD WARNING
This is issued for a combination of strong winds averaging or frequently gusting to, or above, 35 miles an hour and very low visibility due to blowing or falling snow. These are the most dangerous winter storms and can be especially severe when combined with temperatures below 10 degrees. It is not intended to cover a wide-length of time and not issued days in advance. However, once issued and will remain in effect until storm weakens.
HIGH WIND WARNING
This means the expected winds will average 40 miles an hour or more for at least 1 hour or winds gusts will be greater than 58 miles an hour. Trees and power lines can be blown down. A High Wind Warning may be preceded by a HIGH WIND WATCH if the strong winds are not expected to occur for at least 12 hours.
WIND CHILL ADVISORY
This is issued for cold temperatures and winds, with wind chill temperatures computed to be -25 degrees or less for at least 3 hours. Exposure to this combination of strong winds and low temperatures without protective clothing can lead to frostbite and/or hypothermia, Prolonged exposure may be fatal.
WIND CHILL WARNING
This means life threatening cold with wind chill temperatures computed to be -40 degrees or less for at least 3 hours. Exposure to this combination of strong winds and low temperatures without protective clothing will quickly lead to frostbite and/or hypothermia. Longer exposures can be fatal.
WINTER WEATHER ADVISORY FOR SNOW
This is issued for snowfall greater than 4 (but less than 7) inches in a 24 hour period. The snowfall is usually expected to begin within the next 12 hours.
BLOWING SNOW ADVISORY
This is issued when the visibility will be significantly reduced, or when the roads become snow covered over a large area. This doesn't necessarily mean that snow will be falling.
WIND ADVISORY
This is issued for average wind speeds between 31 and 39 miles an hour, or for frequent wind gusts between 46 and 57 miles an hour.
Here's a list of different types of winter precipitation and other winter terms:
Black Ice - A thin coating of glazed ice on a surface. Since this is virtually transparent, you can see the pavement (black asphalt) underneath it making for dangerous travel conditions. Use extreme caution, particularly at night or whenever visibility is reduced. Black Ice often occurs when wet pavement freezes. It can often liquefy during the day and refreeze at night.
Drifting Snow - An uneven distribution of snowfall or existing snow caused by strong surface winds. Drifting snow may occur during or after a snowfall.
Freeze - A condition occurring over a large area when the surface air temperature remains below 32 degrees Fahrenheit for an extended period of time possibly leading to the damage of certain crops.
Freezing Drizzle - Drizzle that falls in liquid form and then freezes upon impact with the ground or an item with a temperature of 32 degrees Fahrenheit or less, possibly producing a thin coating of ice. Even in small amounts, freezing drizzle may cause traveling problems.
Freezing Rain - Rain that falls in liquid form and then freezes upon impact with the ground or an item with a temperature of 32 degrees Fahrenheit or less, possibly producing a thin coating of ice. Even in small amounts, freezing rain can cause traveling problems. Large amounts can pull down power lines and tree branches.
Freezing Fog - When temperatures at ground level drop to or below freezing, the water droplets making up fog often freeze on contact.
Frost - A covering of ice on exposed surfaces when the air temperature falls below the frost point (on average, 36°)
Frozen Dew - When liquid dew changes into tiny beads of ice. The change occurs after dew formation and then the temperature falls below freezing.
Graupel (or Ice Pellets) - A form of frozen precipitation consisting of snowflakes or ice crystals and supercooled water droplets frozen together.
Heating Degree Day - A form of degree day used to estimate the required energy for heating. One heating degree day occurs for each degree the daily mean temperature is below 65 degrees Fahrenheit.
Ice Crystals - A barely visible crystalline form of ice that has the shape of needles, columns or plates. Ice crystals are so small that they seem to be suspended in air. Ice crystals occur at very low temperatures in a stable atmosphere.
Ice Fog - This is fog composed of ice crystals instead of water droplets. Ice fog forms when clear and calm conditions prevail in extremely cold arctic air likely when temperatures When temperatures are 14 degrees Fahrenheit or colder.
Snow - Precipitation composed of white or translucent ice crystals. Snow forms in cold clouds by the direct transfer of water vapor to ice.
Snowflake - White ice crystals that have combined in a complex branched hexagonal form.
Snow Flurries - Intermittent snowfall of short duration. No measurable accumulation of snow typically occurs.
Snow Shower - A short duration of light to moderate snowfall. Accumulations of snow are possible.
Sleet (not to be confused with graupel) - Precipitation consisting of transparent pellets of ice, 5 millimeters or less in diameter. Also called ice pellets. Forms when snow enters a warm layer of air above the surface and melts and then enters a deep layer of sub freezing air on the surface and refreezes.
If your body is left exposed to cold temperatures for a certain duration of time depending on other factors such as the wind, then this can lead to frostbite, hypothermia, or even death. Frostbite can affects the nose, ears, cheeks, chin, fingers, or toes. It can permanently damage any of these areas to the body, and severe cases can lead to amputation.
How do you know if you have frostbite?
When the affected area of the skin turns white or grayish-yellow and/or feels numb and unsually firm or waxy. When this happens seek medical attention immediately. If unavailabe you need to get somewhere warm. Avoid HOT water. If your going to use water make sure its "lukewarm". This can be avoidable by simply limiting outdoor exposure time to cold temperatures. If this is not possible, then make sure your wearing enough layers that covers all the skin and will keep you warm for the entire time you'll be outdoors.
Hypothermia can settle in when the body's temperature drops from the 98.6° to 95°. Severe cases occur when the body's temp drops near 86° or lower. From 1999 to 2011, there was a total of 16,911 deaths in the United States associated with exposure to excessive natural cold. This is a average of 1,301 per year, The highest yearly total of hypothermia-related deaths (1,536) was in 2010 and the lowest (1,058) in 2006. Approximately 67% of hypothermia-related deaths were among males.
When planning outdoor activities, refer to the Wind Chill chart to determine when frostbite might settle in.
The Federal Highway Administration, part of the United States Department of Transportation, estimates that there are about two hundred million people who drive vehicles in U.S. and on average, 5.25 million driving accidents take place every year. Traffic accidents in the winter are most associated with snow and black ice simply from those traveling too fast or not preparing their vehicle for winter weather travel.
Make sure your tires are properly inflated and your brakes, lights, & windshield wipers are working properly. When your traveling on the roads, as visibility is reduced, your vehicle's speed should also be reduced. SLOW DOWN! Increase the gap between your vehicle and the vehicle in front of you. A crash is mostly likely to occur if you are following too closely. If you avoid harsh braking and acceleration, or sharp steering, you have a better ability to control your vehicle.
If you get stuck in the snow here's some tips to know to get you out;
(1) MAKE SURE SNOW ISN'T COVERING YOUR TAILPIPE
(2) DIG AWAY SOME OF THE SNOW/ICE AWAY AROUND THE TIRES
(3) SPRINKLE SALT, SAND, OR CAT LITTER IN FRONT OF THE TIRES
(4) PUT OLD CARDBOARD OR YOUR CARS FLOOR MATS UNDER TIRES
(5) MAKE SURE YOUR WHEELS ARE STRAIGHT
(6) IN LOWEST POSSIBLE GEAR, BACK UP SLOWLY, MOVE FORWARD SLOWLY AND CONTINUE TO REPEAT
Its also recommended you have a safety kit in your vehicle if you become stranded. Regardless to whether your in the middle of nowhere or your nearby a business or your neighborhood its still a necessity you keep certain items in your vehicle. You can actually buy a AAA WINTER EMERGENCY ROAD KIT online or from local retailers. You can also customize your own from scratch. Some things to have is a heavy duty flashlights w/ spare batteries, 3-piece fleece set, (folding) shovel, ice scraper, LED safety strobe, survival blanket, a few candles, box waterproof matches, a few hand warmers, emergency whistle, first aid kit, flares or reflective triangles, jumper cables, extra car fuses, rock salt/kitty litter, rags or paper towels, and some dry food and water. You can also keep an identical safety kit inside your home in case your power goes out. Additionally, a portable battery charger and phone charger can also come in handy.
There's a list of factors that come into play and there's a few terms you'll see me use. What do they all mean?
Meteorologists look at three weather indices called the Arctic Oscillation (AO), the North Atlantic Oscillation (NAO), and the Pacific/North American pattern (PNA). Both the AO/NAO need to be negative. A negative AO readings simply means COLD AIR. A negative NAO reading simply means STORMY or ACTIVE WEATHER PATTERN. The PNA needs to be positive. A positive PNA is associated with a ridge to the west (high pressure & above normal temps) and a trough to the East (low pressure & near or below normal temps). Also, we look for a Greenland Block. This also leads to those negative NAO readings. I'll put it like this, when there is high pressure in the upper atmosphere near Greenland, the jet stream over North America typically buckles downs southward across the eastern half of the United States. This process pulls down cold air and with the setup above, we get theses storms to spin up. When you get these storms to spin up, you can get the snowfall. When you get snowfall on the ground, this helps keep the temperatures down and you can easily have a winter with above normal snowfall and below normal temperatures. The snow on the ground, reflects the sun's rays and doesn't retain heat very well. Whereas, when there is no snow on the ground, the sun radiates the pavements allowing for warmer temperatures.
The image to right is depiction of what the pattern last winter that brought above normal snowfall (DEC-MARCH) and below normal temperatures.
NOTES:
(1) The pattern setup for 2011-2012 was not supportive for lots of snow, therefore, we had a mild winter. Whereas, during the 2012-2013 winter season, snowfall was plentiful in Indianapolis, therefore, overall temps were colder.
(2) During the 2011-2012 winter season (Dec-Feb) we received 8.9" of snow which was the 41st least snowiest winter. The average temperature was 36° making it the 9th warmest winter on record. 2012-2013 compares & you notice the difference. From December 2012-February 2013 We received 19.8" of snowfall. This made it the 44th snowiest winter & temperatures were 2.9° cooler than the 2011-2012 winter season. The average temperature of 33.1° made it the 28th warmest winter.
(3) In the climate summary for the 2012-2013 winter season, NWS Indianapolis, IN didn't not include snowfall we received in March. We received 14.5" which was the greatest for March since 1924 and went down as the 4th snowiest March overall. (DEC-MARCH SNOWFALL TOTAL WAS 34.3"). Snowfall records go back to March 1, 1884. With the snowpack, March and April was cold. We had the 14th coolest March and 74th coolest April on record. High Temperature records began on February 10, 1871 and Low Temperature records began on March 1, 1871.
(4) During the 2012-2013 Winter Season (Dec-Feb) we saw 5 mornings with single digit temperature readings. 4 in January (3 consecutively) with the first occurrence January 2nd. 1 in February on the 1st (last single digit low). The lowest single digit reading was 4° recorded on January 22nd. This was the coldest temperature recorded this season. WE DID NOT SEE SINGLE DIGIT TEMPS during the 2011-2012 winter season, however, we did see single digit temps during the 2010-2011 winter season. The 2010-2011 winter season ranked as the 7th snowiest & 32nd coldest winter.
Here's some stats on the snow we typically see in Indianapolis during a normal year.
NOAA released the outlook in November for 2013-2014 winter season. Since El Nino and La Nina isn't exactly present then there wasn't a clear weather pattern present to accurately forecast this winter's outlook. Therefore, they called for an equal chance of above, below, or near normal temperatures and precipitation/snowfall for the coming winter season. However, when an El Nino and La Nina isn't present, other weather patterns come into play. We look for a "Greenland Block" where high pressure is centered over Greenland. Low Pressure can be stuck for days clogging up patterns in the Eastern half of the U.S. This can result in below normal temperatures and above normal precipitation and snowfall. This particular pattern maybe the setup for the coming winter. Some things we'll need to watch is either for a weak El Nino and/or an active southern jet. So, here is where I think we'll stand in terms of snowfall potential and temperature trends this winter:
- NEAR NORMAL TO ABOVE NORMAL SNOWFALL: The setup for each storm system is impossible to predict. However, trends suggest we're likely to see seasonal snowfall totals that exceed 20". There will likely be gaps of dry weather so we may go time to time without any snowfall. These storms may come in waves that may bring over 2" of snow for each event. Also, we'll need to watch for Lake effect snow showers. These can bring some accumulations as well. A normal winter sees 25.9"
- BELOW NORMAL TEMPERATURES: We're likely to see blasts of Cold Air (frequent arctic intrusions) interrupting brief periods of mild temps resulting in below normal temperatures.
-Average Temperature in December is 31.6°. I think we finish below normal.
-Average Temperature in January is 28.1°. I think we finish below normal.
-Average Temperature in February is 32.1°. I think we finish below normal.
-Overall Average Winter Temp is 30.6°. I think we finish below normal.
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