2012 Atlantic Hurricane Season Birdseye Discussion #133A (Special Update)
...MONDAY OCTOBER 15 2012...12:30 AM EDT...
This special update is written concerning Tropical Storm Rafael...showing a change in direction and intensity since full discussion #133. The surface center of Rafael appears to have made an early northward turn along 65W longitude while regenerating into its heavier t-storm activity. Moreover...the the t-storm activity has become quiet strong over the center such that Rafael is almost a hurricane (75+ mph max winds). In lieu of this development...here is my updated intensity forecast for Rafael
11 PM Sun Oct 14 2012...70 mph...initial
11 AM Mon Oct 15 2012...80 mph...12 hr
11 PM Mon Oct 15 2012...80 mph...24 hr
11 AM Tue Oct 16 2012...80 mph...36 hr
11 AM Wed Oct 17 2012...75 mph (Becoming Non-Tropical)...60 hr
The updated intensity forecast uses the current rate of intensification (10 mph every 12 hours) till 11 AM Monday...when the wind shear from an upper trough (paragraph P1 of discussion #133) begins to increase. Previously I had not predicted any weakening at the end of the forecast...the philisophy being that Rafael transitions into a strong non-tropical low supported the eastern divergence of the upper trough. However...this is the first time I am suggesting an 80 mph peak intensity...and I do not expect that the shear from the upper trough and the cooler waters at the end of the forecast will allow Rafael to be stronger than 75 mph...so I weaken him from 80 to 75 mph by 11 AM Wed (when I expect him to transition to non-tropical).
The earlier than expect northward turn...occuring along 65W longitude...means Rafael will be to the right of my and the NHC's track forecasts shown in Figure 1 of discussion #133...with larger errors occuring with my forecast track that had a leftward bias with respect to NHC's. This also means the threat to Bermuda on Tuesday and threat to eastern Newfoundland (as a non-tropical low) by Thursday is reducing. However...residents in Bermuda remain under a tropical storm watch...and should be acting upon that watch until further notice.
Return to full discussion #133 for an assessment on the rest of the Atlantic tropics.