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000
WTPZ41 KNHC 230846
TCDEP1

HURRICANE KARINA DISCUSSION NUMBER 42
NWS NATIONAL HURRICANE CENTER MIAMI FL EP112014
200 AM PDT SAT AUG 23 2014

Karina continues to show signs of an intermittent eye in shortwave and longwave IR imagery. Dvorak estimates from TAFB, SAB, and UW-CIMSS are unchanged since the last advisory, and several recent AMSU passes have indicated an intensity of 70 to 75 kt. Based on these data, the initial intensity is held at 70 kt. No significant change to the intensity forecast was made. Karina continues to march steadily toward cooler SSTs and a subsequently more stable thermodynamic environment. After 36 hours, the cyclone should encounter an increasingly dry mid-level environment and higher shear, resulting in an increased rate of weakening. Most of the dynamical models forecast that the low- and mid-level centers will become decoupled within 96 hours, but that the low-level center will persist for a day or two after that.

The hurricane is moving toward the northwest at about 7 kt. There remains a high degree of confidence for the first 48 hours of the track forecast. A general east-northeastward track is still expected while Karina interacts with the circulation of Lowell. After Lowell passes to the north, there is a considerable amount of uncertainty regarding the track of Karina and its remnants. Not only is the model spread very large, but the run-to-run consistency has been remarkably poor. For instance, the 00Z and 18Z GFS 120-h forecast positions differ by over 700 nm. The members of TVCE currently support three very distinct scenarios. The GFS shows Karina wrapping around to the north side of Lowell and moving rapidly westward. The HWRF and GFDL models show a slower westward motion, caused by a mid-level ridge that is forecast to build to the east of Lowell. Finally, the ECMWF and UKMET forecast that Karina will be advected southward by the circulation of Marie. The official forecast has been shifted slightly northward, in part due to the extreme shift of the GFS, but remains closest to the middle ground solution of the HWRF and GFDL. If the models begin to converge on a single solution, it may necessitate a larger change to the forecast.



FORECAST POSITIONS AND MAX WINDS

INIT 23/0900Z 16.7N 134.4W 70 KT 80 MPH 12H 23/1800Z 17.4N 133.6W 65 KT 75 MPH 24H 24/0600Z 18.0N 132.2W 60 KT 70 MPH 36H 24/1800Z 18.6N 130.6W 55 KT 65 MPH 48H 25/0600Z 19.2N 129.3W 45 KT 50 MPH 72H 26/0600Z 20.6N 129.2W 35 KT 40 MPH 96H 27/0600Z 21.5N 131.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 28/0600Z 22.0N 133.0W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$ Forecaster Zelinsky/Brown



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