Friday, November 22, 2013

Winter 2013-2014 Outlook for northern and eastern Maine


The official outlook from the Climate Prediction Center (http://www.cpc.ncep.noaa.gov/) for the winter of 2013-2014 for northern and eastern Maine calls for an increased likelihood of above normal temperatures.  There are no strong climate signals that point toward an unusually wet (snowy) or dry winter. 

Without either El Niño or La Niña present, we often use recent climate trends to get insight about what might arise. The average of the past 15 winters has been warmer than average for all of the winters between 1981-2010 across Maine.  This is what tilts the odds in favor of a warmer than normal winter.  It is important to keep in mind that this is a forecast for the average temperature for the entire meteorological winter (December through February).  It does not mean that there will not be a period(s) of extreme cold, just that odds favor that the average temperature for the entire winter will be above normal. It is also important to point out that in the absence of El Niño or La Niña that the skill in making these seasonal forecasts is much lower than when there is a moderate or strong El Niño or La Niña as we head into the winter.

Patterns that can strongly influence our winter weather, such as the Arctic Oscillation, are just not predictable on time scales beyond a week or two. These atmospheric patterns can change from week to week and have the potential to deliver cold, snowy weather throughout the winter season.

Historical American Thanksgiving Weather in nothern and eastern Main

Since being fixed at the fourth Thursday in November by law in 1941, the holiday in the United States can occur on any date from November 22nd to the 28th. When it falls on November 22nd or 23rd, it is not the last Thursday, but the penultimate Thursday in November. Regardless, it is the Thursday proceeding the last Saturday of November. Prior to 1941 Thanksgiving Day was the last Thursday of November. For the purposes of this write-up we will examine the weather on Thanksgiving Day since 1941.

At Bangor, the warmest Thanksgiving was in 1953 when the high temperature was 60 degrees. The lowest temperature observed was 7 above in 1974. The lowest high temperature observed was 19 degrees in 1989. The normal high ranges from 40F on the 28th to 43 on the 22nd. The normal low ranges from 24F on the 28th to 27F on the 22nd.

What are the chances of a white Thanksgiving? We will define a white Thanksgiving as having at least 1 inch of snow on the ground on Thanksgiving Morning. Over the years, a white Thanksgiving has been observed 15 percent of the time. The snowiest Thanksgiving was in 1987 when 11.8 inches of snow was observed.

At Caribou, the warmest Thanksgiving was in 1953 when the high temperature was 61 degrees. The lowest temperature observed was 1 above in 1951. The lowest high temperature of 17 degrees was observed in 1989. The normal high ranges from 33F on the 28th to 35F on the 22nd. The normal low ranges from 19F on the 28th to 22F on the 22nd.

What are the chances of a white Thanksgiving? The chances are much better at Caribou with an inch or more of snow on the ground 61 percent of the time on Thanksgiving morning. The greatest snow depth on Thanksgiving was 25 inches in 1974 when two major snow storms affected the area in the week leading up to Thanksgiving. The snowiest Thanksgiving Day was in 1971 when 7.7 inches of snow was observed.

So, what can we expected this year?  Right now it looks like this coming Thanksgiving will be dry and cold with below normal temperatures.