[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT45 KNHC 020830
TCDAT5
TROPICAL STORM ZETA DISCUSSION NUMBER  12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
4 AM EST MON JAN 02 2006

ZETA IS HOLDING ITS OWN IN THE FACE OF MODERATE WESTERLY UPPER-LEVEL
SHEAR. A SMALL BURST OF CONVECTION WITH CLOUD TOPS TO -60C HAS
REDEVELOPED NEAR AND NORTHEAST OF THE LOW-LEVEL CENTER... AND THE
OVERALL CONVECTIVE CLOUD PATTERN HAS CHANGED LITTLE SINCE THE LAST
QUIKSCAT AND AMSU INTENSITY ESTIMATES MENTIONED IN THE PREVIOUS
DISCUSSION. THEREFORE...THE INITIAL INTENSITY WILL REMAIN AT 45
KT... WHICH IS ALSO SUPPORTED BY A TAFB SHEAR INTENSITY ANALYSIS OF
T3.0/45 KT.

THE INITIAL MOTION ESTIMATE IS 265/06. NIGHTTIME VISIBLE AND
MICROWAVE SATELLITE IMAGERY SUGGEST THAT ZETA MAY HAVE MADE A MORE
WESTWARD TURN DURING THE PAST 6 HOURS UNDER THE INFLUENCE OF A
STRONG EASTERLY LOW-LEVEL WIND SURGE AS NOTED IN QUIKSCAT AND
INFRARED SATELLITE DATA. THE LOW- TO MID-LEVEL RIDGE TO THE NORTH
IS EXPECTED TO REMAIN INTACT FOR AT LEAST THE NEXT 72 HOURS...
STEERING ZETA WESTWARD OR WEST-SOUTHWESTWARD AS THE CYCLONE WEAKENS
AND BECOMES MORE VERTICALLY SHALLOW. THE OFFICIAL FORECAST TRACK IS
SIMILAR TO THE PREVIOUS TRACK AND THE GLOBAL MODEL CONSENSUS.

UW-CIMSS SHEAR ANALYS1S PRODUCTS INDICATE THE VERTICAL SHEAR MAY
RELAX A LITTLE DURING THE NEXT 12 HOURS... WHILE ACCOMPANIED BY A
DECREASE IN THE 200 MB TEMPERATURES. THIS WOULD SUGGEST THAT DEEP
CONVECTION MAY REMAIN INTACT A LITTLE LONGER THAN THE SHIPS MODEL
IS INDICATING. HOWEVER... BY 24-36 HOURS... ALL THE GLOBAL MODELS
AGREE THAT THERE WILL BE A SIGNIFICANT INCREASE IN THE STRENGTH OF
THE MID- TO UPPER-LEVEL WESTERLY WINDS... WHICH SHOULD ACT TO SHEAR
AWAY MOST OF THE ASSOCIATED CONVECTION... AND FINALLY BRING THE
2005 ATLANTIC HURRICANE SEASON TO A MERCIFUL ENDING. EVEN THE
LATEST GFDL MODEL RUN HAS BACKED OFF ON MAKING ZETA A HURRICANE.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL      02/0900Z 24.5N  39.7W    45 KT
 12HR VT     02/1800Z 24.4N  40.5W    35 KT
 24HR VT     03/0600Z 24.3N  41.5W    30 KT
 36HR VT     03/1800Z 24.2N  42.8W    25 KT
 48HR VT     04/0600Z 24.2N  44.6W    25 KT...REMNANT LOW
 72HR VT     05/0600Z...DISSIPATED

$$
This weather bulletin was brought to you by:
www.nashvilleweather.net