Severe Father’s Day Weather – Tropical Storm Chris

A disorganized sub-tropical disturbance monitored by the National Hurricane Center for possible development brought severe thunderstorms and gales to the island for Father’s day.

Father’s day started out with a moist easterly flow as a subtropical disturbance was expected to pass just to our south. However, afternoon heating allowed a strong convective shower to develop on the north side of the disturbance which allowed a small scale low level circulation to develop underneath it – tapping into the broad circulation of the disturbance to do so. The complex of convective showers was noted by the Bermuda Weather Service and a Severe Weather Warning was issued at 2:30pm just as the system moved into the western parishes. The core of heavy rain passed over the western half of the island as it tracked north-northeastward, this made rainfall totals vary 0.30″-1.00″.

Bermuda Weather Service Radar image of the mesoscale convective complex associated with the disturbance exiting the island, headed north-northeast. A small scale, closed low pressure developed as a result of this convective complex. At the time gales were just beginning to be observed at the Bermuda Weather Service. (June 17th 2012 3:23pm)

The Severe Weather Warning was issued calling for wind gusts over 50kts and the potential for funnel clouds/tornadoes. Radar showed rotation, but it didn’t match the signature of a tornado, more that of a mesocyclone – warnings were there to be safe, and rotation was reported in some low hanging clouds in the central parishes.

Because this was not a fully tropical system, the temperatures plummeted in this convective shower as it mixed down rain cooled air and a new record low was observed at the Bermuda Weather Service (66.7F, breaking the old record of 69F in 1950). About half an inch of rain fell across the island, and despite the severe winds, there have been few reports of any damage.

Here are some observations from around the island on June 17th:

Location Lo temp (F) Rainfall peak gust (mph)
BWS, St. Georges 66.7 0.49″ 64
Magnolia Hall, Smiths 69.0 53
myPWS, Devonshire 66.9 0.41″ 42
Devonshire, Devonshire 68.4 0.41″ 32
Knapton Hill, Devonshire 66.6 0.36″ 31
Moore’s Lane, Pembroke 68.0 1.23″ 29
George’s Bay, Sandys 67.0 1.09″ 28

In the afternoon of June 19th, the National Hurricane Center named this same system – Tropical Storm Chris. As of the latest advisory:

Tropical Storm Chris over the far North Atlantic headed eastward. Chris is expected to soon become a post-tropical storm. (NOAA GOES East RGB Satellite Image [JUN 20 2012, 19:45UTC])

“…Chris Heading Towards Cooler Waters, Has Probably Reached Its Peak Intensity…

Summary of 500pm AST (2100 UTC) Information:
Location: 38.5N, 49.0W
About 605mi (970km) SSE of Cape Race, Newfoundland
Maximum Sustained Winds: 60mph (95km/h)
Present Movement: East or 85 Degreees at 21mph (33km/h)
Minimum Central Pressure: 997mb (29.44 inches)”

The storm is expected to continue moving eastward into the open North Atlantic where it will eventually succumb to baroclinic processes and become a post-tropical storm. Chris is not expected to affect further land aside from the large swells that it is generating.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s