Hurricane Gonzalo slowly strengthened overnight and this morning became a category four hurricane. Gonzalo had 130mph 1-minute sustained winds and a minimum central pressure near 949mb as of the 3pm Bermuda time advisory from the National Hurricane Center. This morning Air Force reconnaissance flights into Gonzalo found concentric eye wall features with double wind maxima in addition to this category four intensity. This, in addition to recent satellite based microwave imagery showing a similar convective structure, suggest that Gonzalo is in the process of an eye wall replacement cycle. This process of inner core structural changes will result in fluctuations in intensity today as the inner eye wall weakens and dissipates and the outer eye wall intensifies.
Confidence is increasing in Gonzalo’s track and intensity forecast today. The track reasoning hasn’t changed at all, Gonzalo is tracking northwestward around the southwestern periphery of a deep layer high pressure system over the North Atlantic that is retreating to the east as a cold front approaches from off the United States East coast. Southwesterly flow ahead of the front will then begin to pick up Gonzalo this evening and turn the storm more northward and north-northeastward. This track then continues, taking Gonzalo near Bermuda in two to three days. As Gonzalo approaches Bermuda, wind shear increases and sea surface temperatures decrease and Gonzalo will be on a steady weakening trend as a result. However, this is weakening from a peak as a category four hurricane and Gonzalo will likely still be a major (category three) hurricane on its approach to Bermuda.
A HURRICANE WATCH is in effect for Bermuda and that means that hurricane conditions are possible on Friday. This will likely be upgraded to a warning later today as that timeframe gets closer. Impacts from Gonzalo are expected to be similar to those from Hurricane Fabian (September 2003) and preparations should be made accordingly. Expect the following series of events as adapted from the official Bermuda Weather Service Forecast today at 11:30am. See latest Watches and Warnings.
- Southeasterly winds increase to strong (20-25kts) tonight, isolated light showers continue in the area.
- Southeasterly wind increase through the day Thursday reaching near Tropical Storm force or Tropical Storm force by evening (30-40kts with gusts to 50kts). Isolated to scattered showers increase in intensity, some could be squally and thundery. Seas outside the reef continue to build to 15-25feet. Preparations to protect life and property should be complete by Thursday evening.
- Southeasterly winds veering southerly continue to increase Friday morning. Winds reach near Hurricane or Hurricane force (55-75kts gusting to 95kts) by mid-morning – these are damaging winds. The full force of Gonzalo could be felt depending on exact storm track and structure by early Friday afternoon (~70-90kts gusting to ~110kts). Hurricane force winds continue and veer southwesterly Friday night. Moderate to heavy rain with embedded heavier squalls, possible isolated tornadoes/waterspouts, and life-threatening sea states. Coastal flooding likely in areas of onshore winds, particularly along south shore.
- Southwesterly winds continue to veer westerly and drop markedly Friday evening (30-40kts gusting to 50kts) and drop below tropical storm force overnight into Saturday morning (15-25kts). Rain tapers off and seas begin to abate Friday evening and night.