The link at the image at left shows a 30 hour loop ending 0Z Thursday 19 Feb, 2008. It shows that the cloud over New England is associated with a low pressure system moving in from Colorado. Systems that follow this track are known as Colorado lows. They usually yield moderate precipitation, although this on seemed a little drier than usually. An occluded front (purple) extends southward from the low centered over Southern Ontario on 0Z Thursday. The warm front appears to further south. A cold front extends until the Texas coast. Ahead of the cold front, thunderstorms break out over the southeastern U.S.

A usual, the flow around the low is counterclockwise and inward. Note that southerly flow east the low pressure system brings moisture and low-level cloud northward. At the same time, the cloud deck appear to move in from the west as the jet stream moves the whole system eastward.

Local satellite images for Wednesday afternoon

The image at left shows the visible satellite at 21 UTC Wednesday, February 18 2009. Clicking on the image will link you to a a visible satellite loop of the entire afternoon after 17Z.

The loop shows thin, scattered cloud moving in early from the west. Later in the afternoon, a thicker, more extensive wave of cloud moves in, also from the west. This wave of cloud is the one that brought with it light snow.

The second image shows an IR image for the same time. It links to a loop of IR imagery. It confirms the double wave of cloud, and that the second wave appears to be more extensive. In addition, comparing the cloud shading to the temperature scale at the bottom scale at the bottom shows that the cloud tops have a temperature of about -40 C.

Current and archived imagery can be found at the UCAR's satellite page.

Wednesday's WeatherCam

The above WeatherCam image is for Wed Feb 18, 2008. The time in UTC is displayed at the top right of the animation. A larger animation can be viewed at the LSC Meteorology site webcam archive. It documents a weak storm system moving into the NEK and most of New England from the southwest. The camera faces eastward from the college campus towards Burke Mountain. Clouds moving into the page therefore mover from west to east, and those moving from right to left move form south to north.

The day begins with clear conditions and occasional high level cloud moving across the region from the northwest. Around 11 AM (16 Z) a mid level deck of cloud (at about 5 km or 15 000 feet)moves in from the west with the jet stream. Around 18Z. a lower, thicker deck of clouds moves in rapidly from the south. By sunset around 5 PM (22Z), this deck has lowered to the top of Burke Mountain (about 4000 ft). Snow begins to fall and obstruct the view of the mountain in the final few frames of the animation.