Large Earl Lumbers Along Northeast of Bemuda

Conditions improving in Bermuda today as the hurricane accelerates into the north Atlantic

Despite little change in its strongest winds since yesterday, Earl continued to grow in size as the Category 2 hurricane passed about 100 miles east of Bermuda during the overnight and early morning hours on Friday.

Tropical storm conditions (winds above 38 mph) have been occurring across Bermuda since late yesterday, but conditions will improve today as Earl pulls away. A weather station on the roof of the Commissioner’s House – about 115 feet above sea level (standard wind instrument height is around 33 feet) – at the National Museum of Bermuda measured pressures as low as 990 mb with winds as high as 60 to 70 mph in gusts overnight (worth noting the height of the instrument on the hipped-roof may artificially inflate winds observed closer to the ground). The breadth of Earl’s wind field – with tropical storm winds extending over 200 miles from its center – is impressive and should only grow as it morphs into an even larger extratropical storm over the north Atlantic by tomorrow.

Although Earl’s maximum winds have thus far stayed below the threshold for Category 3 (or “major” hurricanes) – underperforming maximum wind forecasts – the noticeable fall in surface pressures and expansion of its wind field is an important development not to be overlooked. Recent studies have found surface pressure to be a more skillful predictor of damage from hurricanes than maximum winds alone, and larger storms (hurricanes with bigger eyes, effectively) can prove much more destructive than smaller storms, even ones that may have higher maximum winds. So it’s a bit of a misnomer to say Earl hasn’t strengthened since yesterday with pressures now in the low 960s and a much larger wind field.

Studies have shown that larger hurricanes don’t intensify as quickly, and Earl’s difficulty maintaining a closed eye on its south side likely allowed for some intrusion of drier air into its core. Both factors may have contributed to a lower rate of strengthening than initially forecast.

Behind Earl, Invest 95L, now situated in the central Atlantic, has become a naked low-level cloud swirl thanks to blistering upper-level winds giving it a heavy haircut overnight. The disturbance is unlikely to develop in the coming days as it recurves into the north Atlantic.

Visible satellite loop of Invest 95L in the central Atlantic, a swirl of low-level clouds absent deep convection thanks to strong wind shear. Development is unlikely in the coming days as it turns into the open waters of the north Atlantic. Credit: TropicalTidbits.com.

We’ll keep our eyes on a series of disturbances in the eastern Atlantic over the coming week (one already over water and another set to roll off Africa early next week), but for now they’re both a long ways off and pose no immediate threat.