Windy End to 2008 and Cold Start to 2009

An arctic cold front crossed Delmarva today, ushering in cold air for New Year Eve night and New Year's Day. Windy conditions also developed behind the front, as low pressure deepened off the New England coast today. Wind gusts ranged from the 50s to 60 across Delmarva today cause some power outages. The Salisbury Airport recorded a 62 mph wind gust this afternoon. High wind warnings were also in effect throughout the day as well.

Wind chills will become the main factor for New Year's Eve night. Even though the winds will be diminishing overnight, wind chills will be in the teens and eventually single digits early Thursday morning. High pressure then moves over the mid-Atlantic on New Year's Day causing less windy conditions but daytime highs will top out in the 30s. There should still be enough wind on New Year’s to bring wind chills down into the 20s during the day. Not good news for the brave people taking part in the AGH Penguin Swim in Ocean City.

Temperatures moderate some heading into the weekend with highs in the low to mid 40s. earlier this week it looked like we had a decent chance for showers on Friday but now that has diminished greatly. A spotty rain shower is possible Friday afternoon at best and then again on Sunday. Happy New Year and stay safe!

Temperature Inversion

Temperature inversion is an increase in temperature with altitude. Normally, the lower air near the surface is warmer than the air aloft. Of course, when temperature inversions occur this can cause serious damage to the earth's atmosphere. In some cases a smog can be trapped close to the surface of the earth causing air pollution. Several days of smog can cause serious damage to one's health.

In Donora, PA October of 1948 there was an inversion for four days, polluting the air with smog from nearby factories, resulting in 20 deaths and over 1\3 the population was sickened. Sixty years later, the New York Times considered it "One of the worst air pollution disaster in the nation's history".

Also another effect of temperature inversion can develop suppressed convection by acting as a "cap" which is a stable layer of the atmosphere that inhibits the development of convection. When the "cap" is broken for any reason a violent thunderstorms occurs and (or) freezing rain develops in typically colder climates.






Sources:

http://www.wikipedia.com/

http://www.awma.org/about/100years/pollresults2.html


http://hvo.wr.usgs.gov/volcanowatch/2005/05_07_28.html

Alberta Clipper

An Alberta Clipper is a small, fast-moving low pressure system that forms on the Pacific front, over the Rocky Mountain of Alberta Canada. The storm usually travels southeast into the Great Plains and it is followed by a very cold polar air mass. A clipper originates when warm, moist winds from the Pacific Ocean comes into contact with mountains. The air travels down the leeward side of the mountains, often forming a chinook in Alberta, then develops into a storm over the Canadian prairies. The system then comes together with a cold air mass in the winter, and slides southward into a pocket of high pressure, which sends the storm barreling into parts of the central and northeastern US. The storm brings strong winds gusts usually ranging between 35-45 mph with a sharp drop in temperatures in a short period of time. (temperatures can drop 30-40 degrees in a matter of 10-12 hours) Along with strong winds and the cold artic air mass the most brutal part of the storm can be the wind chill temperatures which can easily drop into the single digits. Alberta clippers usually occur between late December and February, some can form as early as November.

Early Season Cold

Arctic air continued to linger over the mid-Atlantic northeast allowing for incredible cold high temperatures this afternoon. Sunday's high temperature was extremely cold as well, only reaching the upper 30s. Today was even colder, with Salisbury reaching 34 degrees and Dover stayed below freezing at 28 degrees. At least the winds were calm, or we could have been dealing with some brutal wind chill values. The last time we had high temperatures this cold was back in February of this year. Check this out, that coldest high temperatures ever for this date was 30 degrees in 1966.

For you cold weather fans, the forecast doesn't look to be in your favor. With the next storms system approaching, highs will reach the 60s on Wednesday but then fall back to the 40s for the end of the week. But looking over the next 10 days or so, there seems to be a pattern change possibly developing that would allow the jet stream to retreat northward and place the arctic air out west. This would allow some milder air to return to the peninsula.

Hail 101

Hail is a product of the updrafts and downdrafts that develop inside storm clouds (cumulonimbus), where supercooled water droplets exist. Water droplets change into frozen pellets when temperatures drop below freezing, as the updraft and downdrafts continue the larger the hail can get before released from the cloud. There are several stages a hailstone can go through depending how long it is in the cloud, first stage is graupel which is very small hail and has a snowflake like structure. The next stage is small hail which is the same size as graupel but has more of a frozen state and is no bigger than 1/5 inch in diameter. The final stage is hailstones, they have layers of ice and are greater than 1/5 inch in diameter; they can be as small as a pea or as large as a grapefruit.
Hail can be the most damaging parts of a thunderstorm, inflicting injury on others, destroying crops & properties. So when in a hailstorm take cover indoors and protect yourself.

Thanksgiving Forecast

First snow fall of 2008 was Friday November 21st, what a way to get you in the Holiday spirit!!! Warming back up this week. It does looks like is going to be another typical Thanksgiving with mild temperatures in the 50s, nice & breezy conditions along the shore! Normally, the past few years on Thanksgiving, temperatures have been above average with cloudy and wet conditions. However, it will stay dry this Thanksgiving & Black Friday! Late Friday night into Saturday morning there is a chance for rain showers to move across Delmarva. So besides a little drizzle for the weekend, things are looking up this year with dry conditions on Thanksgiving but just a little cooler than we are used to on previous Turkey Days. Have a safe & Happy Thanksgiving!

Wind Chill

Tis' the season for wind chill factors!!! When leaving the house on a cold wintry day you may want to check out the wind chill factor, especially if you are planning on for long periods of time. When the air is cold and the wind is blowing it feels a lot colder than it actually is; the actual wind chill temperatures are based on the rate of heat loss from exposed skin. As the wind increases, heat is carried away from the body at an accelerated rate, driving down the skin temperature and eventually the internal body temperature. Therefore, the wind makes it feel much colder. The wind chill factor is always lower than the air temperature; except at conditions well above freezing, where wind chill is considered less important. In this cases, heat index is used, where the apparent temperature is higher than the air temperature. Check out the chart below it gives you a better idea of blowing wind vs. temperatures on a cold wintry day!

Table Chart: http://www.nws.noaa.gov/om/windchill/index.shtml