FAQs about the weather
FAQs about Central NY weather
Utica’s area climate
Q: What's the difference between Dewpoint and Relative Humidity?
A: This is by far the most asked question. The dewpoint is the temperature at which water vapor will condense. You have to think of the dewpoint as an "absolute" measure of how much mositure is in the air. The higher the dewpoint, the more water that is present in the atmosphere.
The relative humidity is an expression of how saturated the air is for a given temperature. Here's the easiest way to remember it: When the temperature and dewpoint are equal, the "relative humidity" is 100%. The air cannot hold any more moisture, at that temperature! If the temperature and dewpoint are far apart, than the relative humidity is low, in other words, the air is relatively dry for the temperature.
Here are some real world examples to help you:
Temperature is 32 F. Dewpoint is 32 F. The air is saturated. The relative humidity is 100%
Temperature is 50 F. Dewpoint is 32 F. The air is somewhat dry for the temperature. The relative humidity in this case is around 50%
Temperature is 68 F. Dewpoint is 32 F. The air is very dry for the temperature. The relative humidity is closer to 20%, something closer to what you'd see in a desert.
In all three cases above, the dewpoint was 32 F. The same exact amount of moisture was in the air in all three cases. The difference is that warmer air can hold more mositure, which therefore, is why the relative humdity dropped as the temperature increased and the moisture stayed the same.
Here's another example for you:
Temperature is 32 F. Dewpoint is 32 F. The relative humidity is 100%.
Temperature is 86 F. Dewpoint is 68 F. The relative humidity is 50%.
In what example is there a greater amount of moisture in the air?
The answer is the second example. You say why? The relative humidity is 50%, isn't it? Yes, but the dewpoint is 68F, meaning that the air is holding a lot more moisture than the first example. The second example is typical of Central NY during a warm and humid summer day, the kind when you sweat by just sitting outside in the shade. Think about it this way, do you sweat when you walk outside and it's 32?
Q: What is Barometric Pressure?
A: Barometric pressure is the pressure at which the air in the atmosphere is exerting on you, or pressing down on you. The pressure is expressed in inches of mercury (how many inches the mercury is forced up a vaccuum tube). By knowing the air pressure (or barometric pressure), and following the changes in barometric pressure, you can find trends in the weather.
Q: What is High Pressure?
A: High pressure, is high atmospheric pressure, which implies sinking air. When the air generally sinks, it tends to dry out and keep clouds from forming, thus, high pressure is usually associated with fair weather.
Q: What is Low Pressure?
A: Low pressure, is low atmospheric pressure, which implies rising air. When the air generally rises, it tends to cool and the mositure in it condenses as it reaches the dewpoint, thus forming clouds, and rain or snow. Low pressure is usually associated with stormy and unsettled weather.
Q: What is the Jet Stream?
A: The jet stream is the rapid movement of air, high up in the atmosphere, that tends to seperate air masses. The strong winds high up in the atmosphere (jet stream winds) guide the air masses, storms, and the areas of High pressure and Low pressure around the globe. The position and strength of the jet stream determines whether storms form or dissipate, and where the warm and cold air masses go.
Q: What is heat lightning?
A: Heat lightning doesn't exist. On a warm summer night, when you see lightning in the sky, what you are seeing is the lightning from thunderstorms in the distance. You can see lightning at night from over 100 miles away. Yes, the heat can generate the thunderstorms, which cause lightning, but the heat alone doesn't cause lightning alone.
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| Q: Why is it so cloudy in Central
A: There are several reasons for this. First off, we are on the western slope of the Appalachian Mountains, which essentially run from Georgia, up the east coast, through Maine. Since the prevailing winds come from the west, the air is forced to rise up when it hits the higher terrain to our east. This causes the air to cool and the moisture to condense, thus forming clouds. We also have a large moisture source less than 100 miles away (Lake Ontario) which adds additional moisture to the air, especially from October to April. In addition to that our hills and mountains can sometimes trap moisture and cool air near the ground in the valleys.
Q: Why is there so much fog, especially in the fall?
A: The longer nights of the late summer and fall in combination with the clear skies and light winds that are common at night in August, September, and October, help temperatures to fall quickly to the dewpoint, the temperature at which water vapor in the air will condense. Once the temperature and dewpoint are the same, you can initiate the formation of fog. If there is still several hours before sunrise when the fog forms and the clear skies and light winds persist, the fog can become very dense, with visibility dropping to zero in spots. Our lakes and rivers, which are warm during that time of year, add additional moisture, and thus adds to the fog. The fog is most common in the valleys, particularly south of Route 20. The valleys of Otsego, Chenango, Madison, and Delaware counties are deep and narrow. These areas cool quickly and have rivers in the valleys, both helping to make fog quickly. The valleys south of Route 20 are among the foggiest in the country, with fog observed over 100 days a year on the average.
Q: Why does it snow so much in Central New York?
A: There are several reasons for this. The number one reason for this is our proximity to Lake Ontario, thus putting our area in line for "lake effect snow" which can generate significant amounts of snow. The second reason is our proximity to several major storm tracks. We are close enough to the coast to receive heavy snow from coastal storms (often referred to as Nor'easters), we are also close to the track of storms that go up the St. Lawrence River Valley, and also the storms that track through the Ohio Valley, Pennsylvania, then off the New England/Long Island coast. Finally, we are also usually in the path of "Alberta Clippers", storm systems that come from Alberta Province, Canada, then move quickly across the Great Lakes and Northeast U.S. These systems are actually quite strong but usually only bring a few inches of snow. This because of two reasons: 1) They move very fast and 2) It is coming from a part of the continent which there is little or no mositure to draw from (No major moisture sources like the Gulf of Mexico, etc.)
Q: Why does it get so humid sometimes in the summer?
A: While we do not see the oppressively humid conditions through the whole summer, we do see it from time to time. The humidity (moisture) comes more from the Gulf of Mexico and the Atlantic Ocean (off the Southeast Coast of the U.S.) than from the Great Lakes. We often refer to the "Bermuda High", the areas of high pressure that sits off the Atlantic Coast, near Bermuda. Winds flow around a high pressure clockwise in the Northern Hemisphere, therefore, it send a south to southwest wind into Central NY. This brings not just the heat, but especially the humidity from the Atlantic, and from the Gulf of Mexico.
Q: Why don't we see the sun much in the winter?
A: You can blame the lack of sun on several things. Obviously the lake effect clouds and snow, along with being near so many storm tracks, are key factors. One thing many people don't think about is the angle of the sun. The sun is at a low angle from November to February (only 23 to 37 degrees above the horizon) and has significantly less heating power than in the summer. The sun causes a process that we call in Meteorology, "mixing", when the sun heats the ground and creates vertical air movement from the surface to around 1 mile above the ground. When there is less "mixing", you cannot mix the low level moisture easily with the drier air that is above the ground, and create breaks in the clouds. In the wintertime you have to physically move the moisture out of our area, horizontally, by a change in the wind direction.
Therefore the low clouds or "Battleship Gray Skies" we sometimes refer to, tend to stay around here longer. In the warmer months, when the sun is stronger and higher in the sky, the sun can partially or almost totally break up the clouds.
Q: Why does the weather change so much over such a small area?
A: All of the factors that have been discussed above in previous questions: The proximity to Lake Ontario, the hills and valleys, and how they are set up, contribute to the unique weather of Central New York. The biggest factor is our terrain. Which direction the hills and valleys face, whether there are forests or open fields near you, contribute significantly to the weather you see in your backyard.
ON THE CLIMATE OF THE UTICA AREA
Meteorologically speaking, the area climate is described as continental, with moderate levels of humidity. The climate is influenced most strongly from nearby Lake Ontario, secondly by the Atlantic Ocean. Other sources that influence local weather can range from the Gulf of Mexico to Canada to the Central Plains of the U.S.
Winters are relatively cloudy and snowy. Nearby Lake Ontario contributes a significant amount of cloud cover and "Lake Effect" snow, a process by which cold air crossing the lake (generally from the west or northwest) becomes saturated, forming clouds and snow downwind from the lake. Where the snow falls is governed by the wind direction. The winds usually take most of the lake effect snow to the north of Utica, over the higher terrain of the Tug Hill Plateau and the Adirondacks. Snow amounts here can average from 150 to over 300 inches per winter compared with the average of 90 to 110
inches in Utica/Rome area. The hills just south of Utica, between the Thruway and U.S. Highway 20, offers a secondary maximum for Lake Effect snow accumulation with an average of 100 to 140 inches per winter. Lake effect does occur south of Route 20 but is not as common due to the increasing distance from the lake and a reduced "fetch" or length of open lake the cold air can cross before they reach this area. Snowfall amounts per winter drop to 60-100 inches heading south of US Route 20. While the lake keeps the area snowy and cloudy, it also protects the area from most outbreaks of severe cold coming from the northern Plains of the U.S. and Canada. While temperatures remain below freezing most of the time, periods of below zero temperatures are not as frequent as areas with the same latitude as Utica, such as Wisconsin, Iowa, and South Dakota.
Spring comes slowly to Utica. Days can still be chilly even well into April. Temperatures during the daytime run from the 40's to the 60's from late March through April with nights in the 20's & 30's. While temperatures at or above 70 degrees can occur anytime after mid-march, they are not common until May. The growing season doesn't begin until the second week in May. Some areas, especially north, wait usually until the second half of May. Sunshine gradually increases from March through May. Rain is common and generally light to moderate. Several days of clouds and rain in a row are typical in March & April. General rainfall gives way to more scattered showers and thunderstorms in May. Thunderstorms become more frequent as the spring goes on and humidity gradually increases.
Summers in the Utica area are among the most enjoyable in the U.S. June through August is the sunniest time of the year with an average of 60 to 70 percent of possible sunshine. Daytime temperatures are comfortable & mostly in the 70's and 80's with overnight lows in the 50's to low 60's. Temperatures do get close to and exceed 90 at times but such heat waves usually last just a few days. Just like in winter, the Great Lakes help to modify the air coming from the Ohio Valley and the Midwest, keeping the area from reaching the 90's more often. Utica averages 22 days at or above 85 and only 5 days at or above 90. Temperatures above 95 are extremely rare. Utica has only hit or exceeded 95 degrees five times in the last 40 years (1966, 1974, 1983, 1987, 2002) and it has been 50 years since the last 100 degree day. Humidity levels are moderate and many days are nice for outdoor activities. Oppressive levels of humidity do occur from time to time. Rainfall is hit and miss and comes mainly from scattered thunderstorms. Thunderstorms do sometimes turn severe but nowhere near as often as areas in the Plains and Ohio Valley. The few storms that turn severe produce minor wind or hail damage. Tornadoes are rare and do not occur every year; most that do form are weak and dissipate quickly. Devastating thunderstorms have occurred but for the most part are extremely rare.
Autumn is another beautiful season in the Utica area. Mild sunny days and clear, cool nights are common from September through mid-October, making for some of the best fall foliage in the U.S. General rainfall begins to occur at this time but usually does not last longer than one to three days. Daytime temperatures range from the 60's and 70's to overnight lows in the 30's and 40's through mid-October. Growing season usually ends in early October for Utica and most of the area, sometimes in late September, especially to the north. Fall is also the "fog season". The Utica area and most of the valleys start off with fog in the morning. This is especially common south of Utica. Most fog usually dissipates before midday. Towards late October and November temperatures cool quickly, cloudy days become common with rainfall increasing in amounts and duration. Rainfall is frequent in November and comes down as snow at times. While snowfall and snow on the ground doesn't become consistent until after November, the month can sometimes bring big snowstorms and/or heavy lake effect snow.
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