March 2012 PWS Report


March 2012 began on a stormy note with two weak systems passing on the 2nd and the 5th bringing only 0.21″ of rain at my location. However, after these systems, a monster ridge of high pressure built over the western Atlantic and parked itself there for two weeks keeping out any storms and any hope of rain.

At its peak, this high pressure had a pressure approaching 1040mb; I personally recorded 30.64″ or 1038mb. This is the highest pressure that I’ve recorded on my personal weather station since I got it at the end of December 2009. It is of note that the return flow on the western edge of this high pressure brought record warmth to the United States and Canada with temperatures reaching into the mid and upper 80s.

A wind shift, associated with a very weak front, overnight on the 10th-11th from the NW to the NE allowed cooler air to filter in and highs only reached the mid-60s. Winds remained fairly light through the period dominated by the High pressure.

Temperatures with the high pressure in place recovered by the 13th and were fairly constant afterwards with highs in the low 70s. There were a few nights that had notable radiation cooling allowing temperatures to fall into the low 50s – this was not reflected in data observed at the Bermuda Weather Service as their more exposed location allowed a light wind to mix in the marine air so temperatures here only fell to near 60F.

This high pressure slowly eroded and shifted eastward for almost two weeks and finally let in a trough of low pressure on the 19th. This brought isolated showers to the region, and only 0.18″ of rain was recorded at my location. However, it signaled the decline of high pressure’s dominance over the western Atlantic.

Storm system approaches on the 25th of March. It breaks the pattern of High Pressure and the dry spell that had developed as a result. (NOAA GOES-East Infrared Satellite Image.)

A cold front was introduced to the area on the 26th  and brought strong winds and rain to the islands. Over the 25th and 26th, 0.15″ of rain was recorded at my location, and winds gusted  to gale force at times behind the front on the 27th. The coldest airmass of the month was in place on decreasing winds for the 28th, with highs only reaching 62F.

Temperatures quickly turned around, reaching 71F for the 29th, on southerly winds ahead of the next storm. March would end on a rainy note with rain being observed on the 29th, 30th, and 31st. However, totals were not too impressive; only 0.15″ was recorded over this period.

March 2012 ended as the driest March on record at the Bermuda Weather Service with only 0.79″ of rain. My totals parallel this with only 0.73″. For my location, the mean high temperature for the month was about 70F while the minimum was about 62F -fairly close to average according to the Bermuda Weather Service climate statistics. High pressure clearly dominated the month with mean monthly pressure at 30.19″ or 1023mb – Bermuda Weather Service observations support this at 30.21″ and 1023mb.

Drought continues into April.

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