Good evening everyone!
Tropical Storm Karen continues on a NNW course this evening. Maximum sustained winds are 65 mph. As of the 5:00 p.m. EDT Advisory from the NHC, the following information was available on Karen, and is contained in the tracking map:
GT 7 KAREN TRACKING MAP / FORECAST TRACK ERROR MAP
Based on satellite loop images throughout the day, the LLC of Karen had become displaced from the convection, which has been pretty much to the NE of the center. This is attributed to around 20 knots of WSW wind shear at the moment. However, based on the latest wind shear tendency map from CIMSS, shear has been on the decrease just to the NW of the storm, and mid level shear drops down to about 5 knots around 2 more degrees from the center position. Current mid level shear is running about 10 knots. These factors may be allowing for the current building of convection almost directly over the center or just on the eastern edge of the center of Karen.
Also noted earlier in the loop, was an outflow boundary, or arc cloud if you will, indicating Karen had taken in some dry air.
The most recent GFS wind shear forecast indicates upper level wind may remain marginal for further intensification, however dry air to her NW may inhibit any steady strengthening. Save any more dry air intrusion, Karen has only one extremely small window of opportunity to attain Category One hurricane status…briefly. Based on the position of Karen in the NHC tracking map, where they designate her a hurricane, a small core of an anticyclonic upper air pattern develops briefly, where wind shear and zonal shear values drop to almost zero…this may be why the NHC still shows minimal hurricane intensity before weakening begins prior to landfall. Based on the current Intensity Model Guidance, we may see a steady drop in intensity around 12 hours prior to landfall, as wind shear will once again increase. Based on this analysis, sustained winds may be around 60-65 mph near landfall.
Based on analysis of the current steering layers mean, and forecast steering layers maps valid for 00Z this evening, I like the NHC forecast track as far as how the track should occur, however current steering indicates Karen may move a little more left, possibly bringing the landfall point one degree west. The current track is a shift from the 18Z dynamic model track guidance, and is a good call by the NHC.
Regardless, albeit Karen may not be a hurricane at landfall, her wind field has been expanded. A HURRICANE WATCH IS IN EFFECT, and residents under the watch area should be making preparations…even though it may just seem precautionary, a HURRICANE WATCH is A HURRICANE WATCH. I added a new preparedness link from FEMA, as the NOAA Preparedness brochure was not available. These links are on the side of the page under BLOGROLLS.
NHC WATCHES AND WARNING TEXT LINK
The following map is interactive..if you have trouble using it…please let me know here, or at firstname.lastname@example.org
TROPICAL CYCLONE POTENTIAL IMPACT GRAPHIC
Residents are urged to monitor NOAA Weather Radio, and LOCAL NWS OFFICE Statements. ALL graphics posted are linked for close up views and interactive information.
NWS LOCAL HURRICANE STATEMENTS
I will continue to monitor Karen closely, and will have another update in the a.m.
Have a blessed evening!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST
MEMBER WEST CENTRAL FL AMS
CERTIFIED SKYWARN OFFICIAL STORM SPOTTER (advanced)