Tropical Cyclone Hettie

[Somerset Squall]

Finally, almost three months after the season began, a tropical cyclone has formed, named Hettie, southeast of Nadi, Fiji. Initial intensity is at 35kts. Hettie is moving south-southwestwards along the western side of a steering ridge to the east, which is expected to build southeast of the system and force a more southwesterly heading soon. Shear is moderate to high at the moment, but good outflow and high ocean heat content is offsetting this which allowed Hettie to develop. Shear is generally decreasing so conditions are looking good for intensification in the near term. On the current track, it won't be long however before Hettie moves over cooler waters which is likely to begin a weakening trend beyond 24hrs and perhaps extratropical transition thereafter. Hettie is not expected to threaten land at the moment.

Fiji Meteoroligcal services have upgraded this system, however JTWC have not yet. However, based on the evidence supporting the 35kt intensity I expect them to upgrade to cyclone this afternoon.

[Somerset Squall]

JTWC upgraded Hettie this afternoon. Intensity remains at 35kts. Although convectional banding is lacking, Hettie certainly is maintaining a very large and deep area of convection over the LLC. It's a good thing this one is nowhere near land because I reckon there would be huge rain totals if it was. The steering ridge is building to the south of Hettie quicker than originally thought which should stop any further southerly movement and enforce a westward track. Whilst this will keep Hettie from cooler waters, the storm is still expected to weaken beyond 12 hours as shear is forecast to get strong again after temporarily easing. Shear is expected to blast Hettie apart pretty quickly. Conditions are quite sheared across the South Pacific as a whole which obviously isn't conducive for development or maintainance of tropical cyclones.

[Cookie]

hmm this system sure can move!! :lol:

[Somerset Squall]

LOL

Latest satellite imagery shows shear has dramatcially increased in the last few hours and Hettie is not coping well. Convection is being blasted to the southeast leaving the LLC exposed. Unless Hettie can re-wrap convection around the centre then she won't survive long.

[Cookie]

yup they shear is battering the system

TROPICAL CYCLONE HETTIE 08F [995HPA] CENTRE WAS LOCATED NEAR 22.0S

177.9W AT 281800 UTC. POSITION POOR BASED ON MTSAT/EIR IMAGERY WITH

ANIMATION. CYCLONE MOVING SOUTH-SOUTHWEST AT ABOUT 07 KNOTS. EXPECT

SUSTAINED WINDS OF 35 KNOTS WITHIN 120 MILES OF CENTRE IN THE

SOUTHEASTERN SEMICIRCLE..

LLCC EXPOSED TO ABOUT 75NM NW OF DEEP CONVECTION. OUTFLOW GOOD TO

SOUTH AND RESTRICTED ELSEWHERE. DVORAK ANALYSIS BASED ON SHEAR

PATTERN YIELDING DT=1.5. PT=MET=2.0. FT=2.0 BASED ON PT, THUS

T2.0/3.0/W0.5/24HRS. SYSTEM LIES IN AN AREA OF 50-KNOT SHEAR

DOWNSTREAM OF AN APPROACHING UPPER SHORT-WAVE TROUGH. CIMMS INDICATES

DECREASING SHEAR TO SOUTH. HETTIE IS EXPECTED TO TURN MORE WESTERLY

UNDER THE LOW-LEVEL E TO NE STEERING FIELD AND SFC RIDGE BUILDING TO

THE SOUTH. GLOBAL MODELS AGREE ON A FORECAST WESTERLY TRACK AND

WEAKENING.

[Somerset Squall]

Intensity has been decreased to 30kts and Hettie declared a remnant low. JTWC issued a final warning at 3am but it appears since then that the remnant low of Hettie has become better orgnised again, with convection exploding directly over the centre, in the face of severe shear. It's questionable whether this convection can persist however, and this is what will need to happen if Hettie is to be re-upgraded to TC status again.

[Cookie]

thanks for the update mate.

Edited January 29, 2009 by cookie