February Summary


NOAA-NESDIS SST Anomaly Feb 27th 2014
Sea-surface anomalies near Bermuda are near 2°C above normal, this anomaly extends through much of the western north Atlantic as shown by this product from NOAA/NESDIS on February 27th. This should be taken with a grain of salt for exact temperature anomalies, but this is a good visualization for the spatial distribution of these sea-surface temperature anomalies.

February started with strings of near record warmth that transitioned to severe thunderstorms and several flash flooding events.  The first nine days of February were characterized by persistent southerly flow around the western side of an unusually strong Bermuda-Azores ridge. This flow brought a maritime tropical airmass into Bermuda with high humidity and near record high temperatures. Records for the beginning of February are generally between 75°F and 77°F, and temperatures were consistently 73-76°F during this period. During the height of this warm period, the Bermuda Weather Service observed a low temperature of 70.3°F on the 6th – it is almost unheard of for low temperatures to not fall below 70°F in February for Bermuda; this has only happened in 1989, 1990, and 1994 – the average low for February 6th is near 60°F. In fact, it is more common for a low to be below 50°F than for the low to be above 70°F in February.

This unusual warmth had continued over from January. Few northwesterly gale events, which are typical this time of year, combined with persistent southerly flow and near record warmth allowed sea surface temperatures to remain well above normal around Bermuda for February. Sea-surface temperatures as measured by the Bermuda Weather Service peaked at 71.4°F on the 6th. 1985-2000 Climatology suggests sea-surface temperatures in Bermuda should be near 65.4°F for the month of February, while in 2014, mean monthly sea-surface temperatures were on average 4.3°F above this, reaching 69.7°F.

Radar imagery from earlier in February showing a severe thunderstorm responsible for the month's peak gust pushing off to the east of Bermuda.
Radar imagery from earlier in February showing a severe thunderstorm responsible for the month’s peak gust pushing off to the east of Bermuda.

The stretch of warm weather ended with a cold front pushing through in the evening of the 9th. This brought showers and gusty winds but only returned temperatures to near normal levels. There was a recovery of temperatures back into the low 70°Fs before another weaker front pushed through on the 12th. Wind quickly returned to the southwest as this front dissipated and another approached on the 13th. This front pushed through with squally showers and thunderstorms, but lingered to the near southeast. Another weak system approaching from the west began to draw the 13th’s front back towards Bermuda as a trough in the morning of the 14th and dumped an excessive amount of rain over Bermuda generally totaling between 2.50″ and 4.00″ and led to flash flooding and wall collapses, mainly in the central parishes. This second front cleared away to the east and a third system approached with strong and severe thunderstorms that quickly blew through on the 15th. Violent storm force gusts were measured by the Bermuda Weather Service at 67mph as a line of thunderstorms clipped the east end, these winds were not observed elsewhere around the island. Because the storms on the 15th were quick to move through, rainfall generally totaled less than 0.25″.

Bermuda now was under cold high pressure and the following days were the coldest of the winter, but were not too far from normal. The month’s lowest temperature was 57.4°F on the 18th; keep in mind the average low is near 60°F. This didn’t last for too long, as by the 19th the front responsible for these cool temperatures dissipated, and winds veered back to the southeast, allowing temperatures to recover to near 70F. Warmth continued as winds veered further to a more southwesterly direction ahead of an approaching frontal system through the 22nd. This frontal system passed in the evening and overnight on the 23rd into the 24th dumping isolated heavy rains, some areas, mainly in the west and central parishes got from 2.75″ to more than 5.00″ of rain during this period while others got closer to an inch. Again, there were some problems with flash flooding. Heavy rains resumed during the day on the 24th generally totaling around an inch.

30-Day Tropical Rainfall Measurement Mission (TRMM) satellite based precipitation anomaly in mm/day.
30-Day  NASA’s Tropical Rainfall Measurement Mission (TRMM) satellite based precipitation anomaly in mm/day. Bermuda is at 5mm/day above TRMM’s climate records for the last 30days, ending March 2nd – encompassing all of February 2014. This should be taken with a grain of salt for exact values, but is a good visualization of the spatial distribution of precipitation anomalies.

After some afternoon light to moderate, steady rains on the 25th on the cool side of the departing front, weather became much more settled for a few days as high pressure built in and temperatures again had no problem recovering into the low 70°Fs. But this reprieve from the deluge that was the second half of February was only short lived as another front pushed through on the 27th. This front stalled to the near southeast of Bermuda overnight and plagued the island with steady post-frontal rain with temperatures in the mid-60°Fs to end the month.

February ended 3.2°F above average based on the 1981-2010 climate period, mean monthly temperatures were 67.6°F, compared to average at 64.4°F. Precipitation totals for the month were officially 8.08″, however locally, monthly totals were likely over 10″ due to isolated heavier rains. For instance, unofficially, a personal weather station in Paget had a monthly total of 10.71″. Based on the same climate period, Bermuda sees 4.87″ of rain on average in February, making February 2014 much wetter than normal. Officially, the wettest February occurred in 1972 with 9.79″ of rain.

The unusual warmth and wetness in February may have implications for the weather in the upcoming spring and summer months in terms of further heavy rain events or even tropical cyclone activity during the early months of Hurricane Season. I will make further comments on these implications in the coming week.

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