TD20 (2145)

4520 TCWC HPCOR CCA
SUBTROPICAL DEPRESSION TWENTY (4520) ADVISORY/DISCUSSION 001
LIVERPOOL ENGLAND MET SERVICE HURRICANE PREDICTION CENTRE
MSHPC OREAN, SER HEADQUARTERS
ISSUED IN CONJUNCTION WITH CYCLONESVILLE, WT WARNINGS SUB-BUREAU
7 PM PAX... 9 PM HPT... 8 PM LOCAL TIME SEP 20 2145
CORRECTED WORD - 'ADVISORY' TO 'INTENSITY'

THIS IS VERY UNEXPECTED... NONE OF US AT THE HURRICANE CENTRE EXPECTED TO BE
HAVING TO SEE OR WRITE THIS ADVISORY... BUT SUBTROPICAL DEPRESSION TWENTY HAS
FORMED ABOUT 1300 KM WEST-NORTHWEST OF NORTH PODGORICA CITY, CRNA GORA LIVENG.

THIS SYSTEM IS IN AN AREA OF RELATIVELY LOW SHEAR FOR ITS LATITUDE... ONLY ABOUT
25 KT... BUT IT IS EXPECTED TO INCREASE TO ABOUT 85 KT IN 72HR. SINCE SSTS ARE
ONLY NEAR 24 C... THIS SYSTEM IS CLEARLY SUBTROPICAL.

THE RECONNAISSANCE PLANE SENT TO CHECK THE SYSTEM FOUND A CLOSED CIRCULATION AND
WINDS OF ABOUT 36 KT AT FLIGHT LEVEL... WHICH IS BEING INTERPRETED AS 30-KT SURFACE.
AS SUCH... THIS WILL BE THE INITIAL INTENSITY. IT IS WORTH NOTING THAT QUIKSCAT PICKED
UP A FEW UNCONTAMINATED 33-KT VECTORS... SO THIS SYSTEM IS VERY NEAR GALE STRENGTH.

AT 9 PM HPT... THE CENTRE OF SUBTROPICAL DEPRESSION TWENTY WAS LOCATED BY QUIKSCAT
NEAR LATITUDE 44.6 NORTH LONGITUDE 5.3 EAST. THIS IS ABOUT 2130 KM... 1330 MILES...
WEST OF CYCLONESVILLE, LIVERPOOL ENGLAND... OR ABOUT 1290 KM... 805 MILES...
WEST-NORTHWEST OF NORTH PODGORICA CITY, CRNA GORA LIV ENG.

THE DEPRESSION IS CURRENTLY ALMOST STATIONARY... ALTHOUGH A SLOW JOG TO THE NORTH-
NORTHWEST COULD OCCUR OVER THE NEXT 24 HOURS OR SO. ON THE FORECAST TRACK... TROPICAL
STORM WATCHES OR WARNINGS COULD BE NEEDED FOR THE WESTERN COAST OF LIVERPOOL ENGLAND
AS EARLY AS TOMORROW.

MAXIMUM SUSTAINED WINDS ARE NEAR 55 KM/H... 35 MPH. THE DEPRESSION COULD STRENGTHEN
TO A STORM IN THE NEXT 12-24 HOURS. MINIMUM CENTRAL PRESSURE MEASURED BY RECON WAS
1007 HPA.

THE DEPRESSION WILL LIKELY MAKE IT TO STORM STRENGTH SOON... BUT STRUGGLE AGAINST
GROWING SHEAR AND FALLING SSTS TO ITS NORTHWEST OR LAND TO ITS NORTHEAST. THE ONLY
WAY IT COULD SURVIVE IS TO MOVE SOUTH... QUICK. STEERING CURRENTS ARE WEAK... SO
THE DEPRESSION IS FORECAST TO REMAIN QUASI-STATIONARY FOR THE NEXT 12 HOURS OR SO
BEFORE A SLOW NNW TRACK.

OFFICIAL FORECAST
INITIAL TIME IS 20/2100H... ALL TIMES HPT
 INITIAL... 44.6 N 05.3 E... 30 KT
21/0300H... 44.6 N 05.4 E... 30 KT
21/0900H... 44.7 N 05.3 E... 35 KT 
21/2100H... 45.0 N 05.1 E... 35 KT 
22/0900H... 45.5 N 04.8 E... 30 KT...DISSIPATING
22/2100H...DISSIPATED

REPEATING THE 9 PM HPT POSITION... 44.6 N 5.3 E. MOVEMENT...ALMOST STATIONARY.
MAXIMUM SUSTAINED WINDS...55 KM/H. MINIMUM CENTRAL PRESSURE...1007 HPA.

THE NEXT ADVISORY WILL BE ISSUED BY THE MSHPC IN CYCLONESVILLE AT 3 AM HPT.

FORECASTERS HUNTER/STELIVA