Storm #2


Bermuda Weather Service Radar Last night near the peak of the strong winds. Much of the heavy rain had already passed to the east. (September 26th 2013 at 6:53pm local time)
Bermuda Weather Service Radar Last night near the peak of the strong winds. Much of the heavy rain had already passed to the east. (September 26th 2013 at 6:53pm local time)

As discussed in the previous post, two waves of low pressure had formed along a stationary front to the south of Bermuda. Yesterday, the first low passed to the near south of Bermuda and indeed brought near gale to gale conditions to Bermuda. Officially the wind peaked, sustained at 37mph with a gust to 50mph at the airport. The more exposed and unofficial Commissioner’s point AWOS reported a peak sustained wind at 58mph with a gust to 72mph. The wind peaked at around 7pm local time last night – a little earlier than initial indications suggested.

In addition to the very strong winds, excessive rain fell widespread around Bermuda with totals of 3-4.5″ for the day island wide. The airport reports 4.10″ of rain for the day yesterday making it one of the wettest days not associated with a Tropical Cyclone in recent memory. This rain led to some flooding problems in the low-lying areas that typically flood including around the Canal in Pembroke and the City of Hamilton. Flooding problems were worst around high tide just after 2pm local time. Heavy rain allowed temperatures to fall to 67.8F – potentially a record low for the day with the lowest temperature for the date between 1949 and 2000 being 69.0F in 1963.

The pressure fell to a significant 1002mb at the airport, and 1001.9mb at my PWS. This indicates that the low pressure system that impacted Bermuda yesterday was fairly strong considering its non-tropical origins this far south in the Atlantic at a time when the atmosphere typically favors tropical cyclone formation.

My rough partial analysis of the North Atlantic this afternoon with low pressure centers marked as red 'L's. Cold fronts marked by blue lines with flags. Warm fronts marked by red lines with scallops. Occluded fronts marked by purple lines with both scallops and flags. A tropical wave is marked by a brown line. Finally, Bermuda is marked by a green dot.
My rough partial analysis of the North Atlantic this afternoon with low pressure centers marked as red ‘L’s. Cold fronts marked by blue lines with flags. Warm fronts marked by red lines with scallops. Occluded fronts marked by purple lines with both scallops and flags. A tropical wave is marked by a brown line. Finally, Bermuda is marked by a green dot.

Meanwhile, a second low is strengthening to the southwest of Bermuda. However, it should take a different track to yesterday’s low. Initially following towards the east-northeast, but then turning more to the northeast and north to the near west of Bermuda. Additionally, compared to the previous forecast, the timing has changed for this event. After a settled day today expect showers to move in during the morning on Saturday with an increasing risk of rain towards evening on Saturday as the low pulls a warm front northwards. After the warm front feature passes to the north on Saturday evening,  rain should turn more showery with heavy downpours possible – this event should be monitored very closely as it develops over the weekend. Showers and possible thunderstorms are then a possibility from Saturday night into Monday. The additional rain that this system could bring may lead to additional flooding issues. See the official forecasts for Bermuda, including watches and warnings at the Bermuda Weather Service.
Below is a summary of my unofficial forecast for Bermuda during this period.

Time Weather
Friday afternoon to Saturday morning Much more settled conditions prevail. Northerly breeze veers to easterly. An isolated shower is possible.
Saturday morning to Saturday night Easterly winds increase to strong and showers or rain start to move in during the morning. Steady rain becomes more likely through the day and should transition to showers that could be heavy and gusty at times – potentially with thunder.
Saturday night to Sunday Strong easterly winds shift to southeasterly then southerly. Showers and thunderstorms continue in the forecast. Some may be squally at times and there may be sunny periods in between.
Sunday through Monday Continued strong southerly flow maintains the chances for showers and thunder and generally unsettled weather until cold front moves through from the west Monday afternoon clearing much of the unsettled weather away and winds veer to the west and begin to subside.
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