TD20 (2145)/Past

Subtropical Depression Twenty

Advisory 1

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

Advisory 2

4520 TCWC HPCWT
SUBTROPICAL DEPRESSION TWENTY (4520) ADVISORY/DISCUSSION 002
LIVERPOOL ENGLAND MET SERVICE HURRICANE PREDICTION CENTRE
MSHPC CYCLONESVILLE, WT WARNINGS SUB-BUREAU
1 AM PAX... 3 AM HPT... 2 AM LOCAL TIME SEP 21 2145

SUBTROPICAL DEPRESSION TWENTY WEAKENS SLIGHTLY...

SUBTROPICAL DEPRESSION TWENTY HAS WEAKENED SLIGHTLY DUE TO DISORGANISATION OF THE
CONVECTION ASSOCIATED WITH THIS SYSTEM. THERE IS A WINDOW OF ABOUT 24-36 HR FOR
THE DEPRESSION TO GET ORGANISED BEFORE IT IS SHEARED TO DEATH.

RECON REPORTED 34KT FLW AT 0012H LOCAL... SO NO CHANGE IN INTENSITY... 30 KT.

AT 3 AM HPT... THE CENTRE OF SUBTROPICAL DEPRESSION TWENTY WAS LOCATED BY RECONNAISSANCE
MISSION NEAR LATITUDE 44.6 NORTH LONGITUDE 5.4 EAST. THIS IS ABOUT 2095 KM... 1310 MI...
WEST OF CYCLONESVILLE, LIVERPOOL ENGLAND... OR ABOUT 1275 KM... 795 MILES...
WEST-NORTHWEST OF NORTH PODGORICA CITY, CRNA GORA LIV ENG.

IT IS CURRENTLY DRIFTING SLOWLY NORTHWARDS... BUT NOT MUCH MOVEMENT IS FORECAST FOR
THE DEPRESSION. THEREFORE... IF THE SYSTEM GAINS STORM STRENGTH/GALE INTENSITY...
TROPICAL STORM WATCHES OR WARNINGS... OR GALE-FORCE WIND ADVISORIES... MAY BE REQUIRED
FOR PARTS OF THE WESTERN TERRITORIES COAST.

MAXIMUM SUSTAINED WINDS ARE NEAR 55 KM/H... 35 MPH. THE DEPRESSION IS EXPECTED TO
STRENGTHEN TO A STORM IN THE NEXT 12 HOURS. MINIMUM CENTRAL PRESSURE MEASURED BY RECON
WAS 1008 HPA.

FOLLOWING REACHING STORM STRENGTH... WITH LITTLE MOVEMENT PREDICTED THE STORM IS EXPECTED
TO EITHER UPWELL ITSELF OR BE SHEARED TO DEATH... OR BOTH... IN ABOUT 60 HR.

OFFICIAL FORECAST
INITIAL TIME IS 21/0300H... ALL TIMES HPT
 INITIAL... 44.6 N 05.4 E... 30 KT
21/0900H... 44.7 N 05.4 E... 35 KT
21/1500H... 44.7 N 05.3 E... 35 KT 
22/0300H... 44.5 N 05.2 E... 30 KT
22/1500H...DISSIPATED

REPEATING THE 3 AM HPT POSITION... 44.6 N 5.4 E. MOVEMENT...SLOWLY NORTHWARD.
MAXIMUM SUSTAINED WINDS...55 KM/H. MINIMUM CENTRAL PRESSURE...1008 HPA.

THE NEXT ADVISORY WILL BE ISSUED BY THE MSHPC IN CYCLONESVILLE AT 9 AM HPT.

FORECASTERS FRABANK/STELIVA

Advisory 3

4520 TCWC HPCWT
SUBTROPICAL STORM DOUGLAS (4520) ADVISORY/DISCUSSION 003
LIVERPOOL ENGLAND MET SERVICE HURRICANE PREDICTION CENTRE
MSHPC CYCLONESVILLE, WT WARNINGS SUB-BUREAU
7 AM PAX... 9 AM HPT... 8 AM LOCAL TIME SEP 21 2145

SUBTROPICAL DEPRESSION TWENTY STALLS... AND STRENGTHENS INTO A SUBTROPICAL STORM...

SUBTROPICAL DEPRESSION TWENTY STALLED EARLIER AND DID NOT MAKE THE EXPECTED SLOW
NORTHWARD DRIFT. SINCE BUOY REPORTS INDICATE A MUCH LOWER CENTRAL PRESSURE... NOW
1003 HPA... AND WINDS OF 33 KT... WE WERE FORCED TO MAKE A DECISION TO EITHER
UPGRADE THIS SYSTEM TO A SUBTROPICAL STORM... OR DECLARE A FULLY-TROPICAL DEPRESSION.
BASED ON SATELLITE IMAGERY... IT SEEMS THAT CALLING THIS A SUBTROPICAL STORM IS
THE BETTER CHOICE. THEREFORE... THE 16TH NAMED STORM/17TH NAMEABLE STORM OF THE
SEASON IS CHRISTENED DOUGLAS.

AT 9 AM HPT... THE CENTRE OF SUBTROPICAL STORM DOUGLAS WAS ESTIMATED TO BE LOCATED
NEAR LATITUDE 44.6 NORTH LONGITUDE 5.4 EAST. THIS IS ABOUT 2095 KM... 1310 MI...
WEST OF CYCLONESVILLE, LIVERPOOL ENGLAND... OR ABOUT 1275 KM... 795 MILES...
WEST-NORTHWEST OF NORTH PODGORICA CITY, CRNA GORA LIV ENG.

IT IS CURRENTLY MOVING SLOWLY TO THE NORTHWEST... AND A SLOW ANTICLOCKWISE TURN IS
EXPECTED IN THE NEXT 12 HOURS OR SO. 

MAXIMUM SUSTAINED WINDS ARE NEAR 65 KM/H... 40 MPH. MINIMUM CENTRAL PRESSURE AS TAKEN
FROM BUOY X12LE3Y... NEAR 44.6 5.1... IS 1003 HPA.

TROPICAL STORM-FORCE WINDS... GALE STRENGTH... EXTEND OUTWARD UP TO 280 KM... 175 MI...
FROM THE CENTRE OF THE SYSTEM.

DEPENDING ON THE TRACK THE STORM TAKES... IT COULD DISSIPATE WITHIN 36 HR... OR BE
A HIGH-END TS IN 36 HR. THE OFFICIAL FORECAST IS MADE WITH LOW (15-30 PERCENT) CONFIDENCE
BUT WILL FOLLOW THE FORMER SCENARIO PRESENTED.

OFFICIAL FORECAST
INITIAL TIME IS 21/0900H... ALL TIMES HPT
 INITIAL... 44.6 N 05.4 E... 35 KT
21/1500H... 44.7 N 05.3 E... 35 KT
21/2100H... 44.6 N 05.3 E... 35 KT 
22/0900H... 44.4 N 05.2 E... 25 KT...DISSIPATING
22/1500H...DISSIPATED

REPEATING THE 9 AM HPT POSITION... 44.6 N 5.4 E. MOVEMENT...SLOWLY NORTHWESTWARD.
MAXIMUM SUSTAINED WINDS...65 KM/H. MINIMUM CENTRAL PRESSURE...1003 HPA.

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

FORECASTER STELIVA

Advisory 4

4520 TCWC HPCWT
TROPICAL STORM DOUGLAS (4520) ADVISORY/DISCUSSION 004
LIVERPOOL ENGLAND MET SERVICE HURRICANE PREDICTION CENTRE
MSHPC CYCLONESVILLE, WT WARNINGS SUB-BUREAU
1 PM PAX... 3 PM HPT... 2 PM LOCAL TIME SEP 21 2145

SUBTROPICAL STORM DOUGLAS BECOMES TROPICAL AS IT STRENGTHENS...

QUIKSCAT INDICATES THAT THE SYSTEM NOW HAS HIGHER SUSTAINED WINDS... WITH A 45-KT
VECTOR OBTAINED... AS WELL AS MANY 40-KT VECTORS. THE SATELLITE APPEARANCE OF
DOUGLAS HAS IMPROVED... AND THIS IS JUSTIFICATION FOR DECLARING DOUGLAS FULLY
TROPICAL AT 40 KT. IT NOW SEEMS THAT THE NW/W TURN WILL NOT OCCUR... AND A SLOW
CLOCKWISE MOVEMENT IS ANTICIPATED OVER THE NEXT 72 HOURS CULMINATING IN LANDFALL
NEAR 60 HOURS. DUE TO AN EXPANDING WINDFIELD... AND WITH FURTHER EXPANSION OF
STRONGEST WINDS RADII EXPECTED... TROPICAL STORM WARNINGS AND HURRICANE WATCHES
HAVE BEEN INITIATED FOR MUCH OF THE WESTERN COAST OF THE WESTERN TERRITORIES.

AT 3 PM HPT... THE CENTRE OF TROPICAL STORM DOUGLAS WAS LOCATED BY SATELLITE
NEAR LATITUDE 44.7 NORTH LONGITUDE 5.3 EAST. THIS IS ABOUT 2145 KM... 1340 MI...
WEST OF CYCLONESVILLE, LIVERPOOL ENGLAND... OR ABOUT 1320 KM... 825 MILES...
WEST-NORTHWEST OF NORTH PODGORICA CITY, CRNA GORA LIV ENG.

A TROPICAL STORM WARNING IS CURRENTLY IN EFFECT FOR THE WESTERN COAST OF LIVERPOOL
ENGLAND FROM 46.8N 6.9E... ALONG THE COAST ABOUT 1775 KM NORTHWEST OF CYCLONESVILLE
SOUTHWARD TO 43.7N 7.3E... ALONG THE COAST ABOUT 710 KM WEST OF NORTH PODGORICA CITY.

A HURRICANE WATCH IS CONCURRENTLY IN EFFECT FOR THE WESTERN COAST OF LIVERPOOL
ENGLAND FROM 46.2N 7.0E... ALONG THE COAST ABOUT 550 KM WEST OF THE WT COMMEMORATION
LANDMARK... SOUTHWARD TO 44.9N 7.2E... ALONG THE COAST ABOUT 1615 KM WEST-NORTHWEST
OF CYCLONESVILLE.

IT IS CURRENTLY MOVING NORTH AT ABOUT 9 KM/H OR 6 MPH... AND A SLOW CLOCKWISE TURN
IS EXPECTED IN THE NEXT 72 HOURS OR SO. 

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 75 KM/H... 45 MPH. MINIMUM CENTRAL 
PRESSURE IS ESTIMATED TO BE 1000 HPA.

TROPICAL STORM-FORCE WINDS EXTEND OUTWARD UP TO 385 KM... 240 MI... FROM THE CENTRE
OF THE STORM. IT IS EXPECTED THAT THIS WIND FIELD WILL EXPAND AS IT TRACKS SLOWLY
NORTH TO NORTH-NORTHEAST.

THE PREVIOUS PROGNOSTIC REASONING HAS BEEN TOTALLY WRONGED. TS4520 IS CURRENTLY TRACKING
ALONG A WEAKNESS IN THE SUBTROPICAL RIDGE... AND WILL CONTINUE TO DO SO UNTIL LANDFALL
AROUND TAU60... LIKELY AS A HURRICANE. THE OFFICIAL INTENSITY FORECAST... WHILE TAKING
INTO ACCOUNT 24C SSTS AND GROWING SHEAR... WILL CALL FOR GRADUAL STRENGTHENING AS IT
MOVES OVER SLIGHTLY WARMER WATERS TO ITS NORTHEAST... REACHING HURRICANE STRENGTH IN
ABOUT 48 HOURS. AFTER THAT... LIKELY RAPID WEAKENING ONCE INLAND.

OFFICIAL FORECAST
INITIAL TIME IS 21/1500H... ALL TIMES HPT
 INITIAL... 44.7 N 05.3 E... 40 KT
21/2100H... 44.9 N 05.3 E... 40 KT 
22/0300H... 45.1 N 05.4 E... 45 KT 
22/1500H... 45.5 N 05.8 E... 55 KT 
23/0300H... 45.8 N 06.4 E... 60 KT 
23/1500H... 45.4 N 06.8 E... 65 KT 
24/1500H... 44.5 N 07.8 E... 25 KT...DISSIPATING INLAND 
25/1500H...DISSIPATED

REPEATING THE 3 PM HPT POSITION... 44.7 N 5.3 E. MOVEMENT...NORTHWARD NEAR 9 KM/H.
MAXIMUM SUSTAINED WINDS...75 KM/H. MINIMUM CENTRAL PRESSURE...1000 HPA.

THE NEXT ADVISORY WILL BE ISSUED BY THE MSHPC IN CYCLONESVILLE AT 9 PM HPT.

FORECASTER STELIVA

Advisory 5

4520 TCWC HPCWT CCA
TROPICAL STORM DOUGLAS (4520) ADVISORY/DISCUSSION 005
LIVERPOOL ENGLAND MET SERVICE HURRICANE PREDICTION CENTRE
MSHPC CYCLONESVILLE, WT WARNINGS SUB-BUREAU
7 PM PAX... 9 PM HPT... 8 PM LOCAL TIME SEP 21 2145
CORRECTED ISSUANCE TIME

NOTICE - DUE TO TECHNICAL DIFFICULTIES NO WARNING GRAPHIC IS AVAILABLE FOR
WARNING NR. 5. WARNING GRAPHICS WILL RESUME WHEN THE MSHPC HEADQUARTERS IN
OREAN RESUMES NORMAL ACTIVITY.

TROPICAL STORM DOUGLAS INTENSIFIES A LITTLE MORE...

BASED ON A QUIKSCAT PASS FROM TWO HOURS AGO THE TROPICAL STORM HAS INTENSIFIED
OVER THE LAST SIX HOURS. WIND SPEEDS OF 45 KT WERE CAPTURED IN THE QUIKSCAT PASS...
AND A FEW RAIN-MARRED 50-KT VECTORS. SLOWLY MOVING NORTHWARDS... 015/04KT.
LOCAL WARNINGS MAY BE IN EFFECT. TROPICAL STORM WARNINGS AND HURRICANE WATCHES
REMAIN IN EFFECT FOR MUCH OF THE WESTERN COAST OF THE WESTERN TERRITORIES.

AT 9 PM HPT... THE CENTRE OF TROPICAL STORM DOUGLAS WAS LOCATED BY SATELLITE
NEAR LATITUDE 44.9 NORTH LONGITUDE 5.3 EAST. THIS IS ABOUT 2130 KM... 1330 MI...
WEST OF CYCLONESVILLE, LIVERPOOL ENGLAND... OR ABOUT 1355 KM... 845 MILES...
WEST-NORTHWEST OF NORTH PODGORICA CITY, CRNA GORA LIV ENG.

A TROPICAL STORM WARNING IS CURRENTLY IN EFFECT FOR THE WESTERN COAST OF LIVERPOOL
ENGLAND FROM 46.8N 6.9E... ALONG THE COAST ABOUT 1775 KM NORTHWEST OF CYCLONESVILLE
SOUTHWARD TO 43.7N 7.3E... ALONG THE COAST ABOUT 710 KM WEST OF NORTH PODGORICA CITY.

A HURRICANE WATCH IS CONCURRENTLY IN EFFECT FOR THE WESTERN COAST OF LIVERPOOL
ENGLAND FROM 46.2N 7.0E... ALONG THE COAST ABOUT 550 KM WEST OF THE WT COMMEMORATION
LANDMARK... SOUTHWARD TO 44.9N 7.2E... ALONG THE COAST ABOUT 1615 KM WEST-NORTHWEST
OF CYCLONESVILLE.

IT IS CURRENTLY MOVING NORTH AT ABOUT 8 KM/H OR 5 MPH... AND A SLOW CLOCKWISE TURN
IS EXPECTED IN THE NEXT 60 HOURS OR SO. 

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 85 KM/H... 50 MPH. MINIMUM CENTRAL 
PRESSURE IS ESTIMATED TO BE 999 HPA.

TROPICAL STORM-FORCE WINDS EXTEND OUTWARD UP TO 410 KM... 255 MI... FROM THE CENTRE
OF THE STORM. IT IS EXPECTED THAT THIS WIND FIELD WILL EXPAND AS IT TRACKS SLOWLY
NORTH TO NORTH-NORTHEAST.

TS4520 CONTINUES TO TRACK ALONG A WEAKNESS IN THE SUBTROPICAL RIDGE... AND WILL
CONTINUE TO DO SO UNTIL LANDFALL BY TAU60... LIKELY AS A HURRICANE. THE OFFICIAL
INTENSITY FORECAST... WHILE TAKING INTO ACCOUNT FALLING SSTS AND GROWING SHEAR... IS
NOW MORE CONSERVATIVE... BUT WILL STILL CALL FOR GRADUAL STRENGTHENING TO A HURRICANE.

OFFICIAL FORECAST
INITIAL TIME IS 21/2100H... ALL TIMES HPT
 INITIAL... 44.9 N 05.3 E... 45 KT 
22/0300H... 45.1 N 05.4 E... 45 KT
22/0900H... 45.4 N 05.6 E... 45 KT 
22/2100H... 45.6 N 06.1 E... 50 KT 
23/0900H... 45.6 N 06.7 E... 55 KT 
23/2100H... 45.2 N 07.0 E... 65 KT...SHORTLY BEFORE LANDFALL 
24/2100H...DISSIPATED

REPEATING THE 9 PM HPT POSITION... 44.9 N 5.3 E. MOVEMENT...NORTHWARD NEAR 8 KM/H.
MAXIMUM SUSTAINED WINDS...85 KM/H. MINIMUM CENTRAL PRESSURE...999 HPA.

THE NEXT ADVISORY WILL BE ISSUED BY THE MSHPC IN CYCLONESVILLE AT 8 PM HPT.

FORECASTER STELIVA