Tropical Storm Karen is no longer a viable storm system as fierce upper-level wind shear has shredded the system and destroyed its cyclonic convection.

Here’s the latest update from the National Hurricane Center at 5:00 PM on 9-29:

TROPICAL DEPRESSION KAREN DISCUSSION NUMBER 20
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL122007
500 PM EDT SAT SEP 29 2007

THE SHEAR HAS BEATEN KAREN. SATELLITE IMAGES INDICATE THAT KAREN NO LONGER HAS A WELL-DEFINED CENTER AND BASICALLY DOES NOT QUALIFY AS A TROPICAL DEPRESSION.

HOWEVER…THERE IS STILL A BROAD AREA OF LOW PRESSURE WITH STRONG SQUALLS IN A FEW CONVECTIVE BANDS OVER THE EASTERN HALF OF THE CIRCULATION. THE BROAD AREA OF LOW PRESSURE…OR THE REMNANTS OF KAREN…ARE EXPECTED TO CONTINUE MOVING TOWARD THE NORTHWEST OR 315 DEGREES AT 8 KNOTS

Storm Update #5
Tropical Storm Karen is west of the Windward Islands on a heading of 290/9, meaning she’s heading much more westerly than before at a slower 9 knots. Karen is currently heavily affected by high-level wind shear which is expected to lessen in 48 hours.

Latest Tropical Storm Karen predicted path on 9-28:
Tropical Storm Karen 9-28 
Note how the storm track now has a pronounced westward shift.

Current satellite view:
Tropical Storm Karen satellite view 9-28

Latest Tropical Storm Karen forecast  from NHC:

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL STORM KAREN…LOCATED ABOUT 755 MILES EAST OF THE WINDWARD ISLANDS…THE CURRENT DIRECTION IS AN UNCERTAIN 290/9. KAREN IS EXPECTED TO MOVE ON A GENERAL WEST-NORTHWESTWARD TO NORTHWESTWARD TRACK FOR THE NEXT TWO TO THREE DAYS IN RESPONSE TO A LOW- TO MID-LEVEL RIDGE TO THE NORTH OF THE CYCLONE.

IN 48-72 HOURS…A MID-LATITUDE TROUGH IS EXPECTED TO APPROACH THE CYCLONE FROM THE WEST…AND IT IS DIFFICULT TO DETERMINE HOW MUCH OF A NORTHWARD STEERING INFLUENCE THE TROUGH WILL HAVE ON KAREN.

BY DAY 4…MOST OF THE GUIDANCE AGREES THAT A MORE WEST-NORTHWESTWARD TO WESTWARD MOTION COULD OCCUR AS THE TROUGH MOVES EAST AND HIGH PRESSURE BUILDS BACK IN TO THE NORTH OF THE CYCLONE.

THE STRONG WESTERLY SHEAR CURRENTLY AFFECTING THE CYCLONE IS EXPECTED TO PERSIST FOR THE NEXT 48 HOURS OR SO. THE SHEAR IS FORECAST TO RELAX AS RIDGING TO THE NORTH RETURNS. IF KAREN IS ABLE TO SURVIVE THE SHEAR FOR THE NEXT 48 HOURS…RESTRENGTHENING COULD OCCUR IN THE LATER FORECAST PERIODS.

Storm update #4
Tropical Storm Karen is now forecast to become Hurricane Karen with category 2 winds within 5 days. The latest National Hurricane Center forecast for Karen shows her reaching hurricane strength within a day as the tropical storm races toward the Windward Islands.

Here is Hurricane Karen’s projected storm track on 9-26:
Tropical Storm Karen storm track 9-26

Here is a satellite view of Tropical Storm Karen on 9-26:
Hurricane Karen winds 9-26

Click here for a current satellite view of Karen’s winds and storm path in a time-lapse loop.

Tropical Storm Karen official NHC forecast:

KAREN IS MOVING RIGHT ALONG THE PREVIOUS FORECAST TRACK WITH AN INITIAL MOTION OF 280/11. WITH THE RECENT DEVELOPMENT OF CONVECTION NEAR THE CENTER AND GENERALLY FAVORABLE ENVIRONMENTAL CONDITIONS…KAREN SHOULD STRENGTHEN DURING THE NEXT DAY OR TWO.THEREAFTER…THE INTENSITY FORECAST BECOMES HIGHLY PROBLEMATIC DUE TO THE POSSIBLE DEVELOPMENT OF UNFAVORABLE UPPER-LEVEL WINDS. THE GLOBAL MODELS SHOW STRONG WESTERLY FLOW IMPINGING UPON THE CYCLONE IN A DAY OR TWO.

HOWEVER…NEITHER THE GFDL NOR THE HWRF MODELS RESPOND TO THE SHEAR AND CONTINUE TO STRENGTHEN KAREN THROUGHOUT THE FORECAST. IN FACT…THE HWRF MODEL MAKES KAREN A CATEGORY 2 HURRICANE BY DAY 5.

SINCE SUCH ROBUST DEVELOPMENT SEEMS QUESTIONABLE GIVEN THE EXPECTED INCREASE IN VERTICAL SHEAR…THE OFFICIAL FORECAST IS BASED MORE ON THE SHIPS AND LGEM MODELS WHICH SHOW KAREN REACHING MINIMAL HURRICANE STRENGTH IN A DAY OR TWO FOLLOWED BY SLIGHT WEAKENING.

Storm Update #3
Tropical Storm Karen has strengthened rapidly and will become Hurricane Karen by Friday according to the 9-25-07 forecast from The National Hurricane Center. Here are the latest storm track predictions and satellite views of Tropical Storm Karen.

Tropical Storm Karen projected path 9-25

Here is the satellite view so you can see Karen’s current size:
Tropical Storm Karen satellite view 9-25-07

Here are excerpts of the forecast discussion from the National Hurricane Center on 9-25-07 at 8:00 AM:

THE INITIAL MOTION REMAINS 285/14. KAREN IS ON THE SOUTH SIDE OF A LOW/MID-LEVEL RIDGE…WHICH SHOULD STEER THE CYCLONE FOR THE NEXT 36-48 HR. AFTER THAT…THE LARGE-SCALE MODELS AGREE ON THE DEVELOPMENT OF A MID/UPPER-LEVEL TROUGH TO THE NORTHEAST OF THE LESSER ANTILLES…WHICH WOULD TURN KAREN NORTHWESTWARD OR NORTHWARD.THE INTENSITY FORECAST…IF ANYTHING…HAS BECOME MORE PROBLEMATIC. KAREN IS CURRENTLY IN AN ENVIRONMENT OF LIGHT NORTHWESTERLY VERTICAL WIND SHEAR…WHICH SHOULD CONTINUE FOR 24-36 HR.

THE SHIPS…GFDL…AND HWRF MODELS ALL FORECAST KAREN TO BECOME A HURRICANE BY 60-72 HR. GIVEN THE UNCERTAINTY IN THE STRENGTH OF THE SHEAR…THE INITIAL INTENSITY FORECAST CALLS FOR KAREN TO PEAK JUST BELOW HURRICANE STRENGTH.

And that’s about it for this update. Bookmark this page because we’ll keep updating it with the latest information on Karen’s direction and projected storm track.

Storm Update #2:
Tropical Storm Karen is rapidly gaining strength and is predicted to reach hurricane strength in as little as 48 hours. Here’s the latest projected storm path for Karen from the National Hurricane Center:

Tropical Storm Karen 9-24-07
Tropical Storm Karen may not curve North as fast as this map shows.

Here’s the official forecast from 9-24 at 11:00 PM which still has quite a variance in the NHC’s storm track guidance for Karen:

THE INITIAL MOTION ESTIMATE IS 285/14. THE DEPRESSION IS EXPECTED TO CONTINUE MOVING WEST-NORTHWESTWARD SOUTH OF A MID-LEVEL RIDGE OVER THE CENTRAL AND EASTERN ATLANTIC DURING THE NEXT FEW DAYS.THE INTENSITY FORECAST IS SOMEWHAT PROBLEMATIC. THE DEPRESSION APPEARS TO BE IN A FAVORABLE ENVIRONMENT FOR STRENGTHENING DURING THE NEXT COUPLE OF DAYS.

THE SHIPS MODEL BRINGS THE DEPRESSION TO HURRICANE STATUS IN 48 HOURS WHILE THE DYNAMICAL MODEL GUIDANCE IS LESS AGGRESSIVE DURING THIS TIME FRAME.

Pay attention to where it says that in some of the computer models, the storm could be Hurricane Karen within 48 hours. That’s an awfully quick upswing in intensity for a newly formed tropical storm…

Best to keep a close eye on this one!

Storm Update #1 on 9-24-07 at 9:00 AM
Tropical Storm Karen is on her way as you can see in these satellite photos of tropical storm activity from the National Hurricane Center.

And, as we know all too well, tropical storms forming off the coast of Africa become hurricanes rather quickly as they roll across the Atlantic, so she could easily be Hurricane Karen in a few more days.

Tropical Storm Karen

Here is the most recent forecast for Tropical Storm Karen:

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1130 AM EDT MON SEP 24 2007FOR THE NORTH ATLANTIC…CARIBBEAN SEA AND THE GULF OF MEXICO…

AN AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS LOCATED IN THE VICINITY OF THE WINDWARD ISLANDS. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THIS SYSTEM ARE NOT WELL-ORGANIZED AT THIS TIME….
BUT THERE IS THE POTENTIAL FOR THIS LOW TO BECOME A TROPICAL DEPRESSION DURING THE NEXT DAY OR TWO AS IT MOVES NORTHWESTWARD AT ABOUT 15 MPH. THE SYSTEM IS EXPECTED TO BRING SQUALLY WEATHER TO PORTIONS OF THE WINDWARD AND LEEWARD ISLANDS TODAY AND TOMORROW.
INTERESTS IN THE LESSER ANTILLES SHOULD MONITOR THE PROGRESS OF THIS SYSTEM.

AN AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS LOCATED ABOUT 730 MILES WEST-SOUTHWEST OF THE CAPE VERDE ISLANDS. THIS LARGE SYSTEM CONTINUES TO SHOW SIGNS OF ORGANIZATION…AND IT COULD DEVELOP INTO A TROPICAL DEPRESSION DURING THE NEXT DAY OR SO AS IT MOVES WEST-NORTHWESTWARD AT ABOUT 15 MPH.

And that’s about it for our first look at this storm system. Stay tuned for more and bookmark this page for the latest on Tropical Storm Karen.

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