Karen Slightly Stronger; Forecast To Become A Remnant Low In A Few Days

SUMMARY OF 1000 AM CDT INFORMATION
LOCATION…26.6N 63.3W
ABOUT 405 MI…650 KM SSE OF BERMUDA
MAXIMUM SUSTAINED WINDS…45 MPH…75 KM/H
PRESENT MOVEMENT…NNE OR 15 DEGREES AT 14 MPH…22 KM/H
MINIMUM CENTRAL PRESSURE…1004 MB…29.65 INCHES

Karen has been maintaining a cluster of convection to the west of its center, but visible satellite images and wind data from NOAA buoy 40149 to the northeast suggest that the low-level circulation is becoming elongated. This structure has been confirmed by a late-arriving ASCAT pass, and that data also show that Karen is producing winds to 40 kt within the deep convection.

Karen is embedded in the flow between a mid-level high centered over the central Atlantic and a mid- to upper-level low which is slowly retrograding westward over the Bahamas. This is maintaining a north-northeastward motion of 015/12 kt. The central Atlantic high is expected to weaken over the next 2 days, while a new high develops over the western Atlantic, causing Karen to make a clockwise loop well to the southeast of Bermuda. Once the western Atlantic high becomes established, Karen is then expected to move generally westward on days 3 through 5. There have been no significant changes among the track models, and the new NHC track forecast is therefore very similar to the previous one.

Relatively light winds aloft and warm ocean waters could allow Karen to maintain its intensity for another day or two. After that time, however, an increase in northerly shear will likely allow ambient dry air to infiltrate into the circulation further. The dynamical models–which we’re now heavily favoring in our forecasts–are showing gradual weakening and even a loss of organized deep convection in a few days. Therefore, Karen is now forecast to degenerate into a remnant low by day 3. The low is expected to plow into strong southwesterly shear on days 4 and 5 while it moves westward over the southwestern Atlantic, which should keep it as a remnant low or possibly cause it to open up into a trough of low pressure.

Category: ALL POSTS, Tropical