Warm, Rainy start to November in Bermuda


November has certainly started with notable warm spells and several heavy rain events. November is one of the months where Bermuda’s weather transitions from being dominated by the Bermuda-Azores High to being led by the mid-latitude storm track. The extra-tropical storms of the mid-latitudes function by moving air masses of different temperature and moisture characteristics north and south. Therefore during this transition month, it is not uncommon for large swings in weather.

[How air masses move in extratropical cyclones: Schematic]

November High temp to date
Range of high temperatures for Bermuda (for the period 1948-2013) compared to the observed high temperatures for Bermuda. Both data recorded at the Bermuda Weather Service. (click for larger)

November 2014 so far has experienced such swings in weather, the month started with a near gale event and several days of much below normal temperatures with several low temperatures in the low to mid-60s which is about 5F below normal. This air mass followed a cold front that later stalled to the south of the island and lifted north across the island bringing very heavy rain between the 6th and 9th. Rainfall totals were over 4 inches for that period, more than 2.71″ of rain was recorded at the Bermuda Weather Service in one day during this period. November typically has around 4 inches of rain for the entire month.

The heavy rains were then followed by several days of much warmer than normal weather. A peak temperature of 81.3F on the 10th was accompanied by a four day string where relative humidity failed to fall below 90%. Temperatures during this period were in the upper-70s, record highs this time of year are around 80-82F.

westatlantic-radar-2014-11-12-1313
Bermuda Weather Service Radar at 1:13pm local time, November 12th 2014 showing a band of thunderstorms that brought gusty winds to the island.

A cold front and associated trough brought showers and thunderstorms to the island on the 12th with some gusty winds. This brought additional rains and some unofficial wind gusts peaked at 30-40kts as gusty thunderstorms moved in. This cold front allowed a cooler air mass to filter in from the west, but only marginally so as temperatures continue above normal.

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