
IDDP0002
Australian Government Bureau of Meteorology
Northern Territory
Darwin Regional Forecasting Centre
TOP PRIORITY FOR IMMEDIATE BROADCAST
Media: The Standard Emergency Warning Signal should NOT be used with this
warning.
TROPICAL CYCLONE WARNING
TROPICAL CYCLONE ADVICE NUMBER 2
Issued by the BUREAU OF METEOROLOGY, DARWIN
at 2:00 pm CST [12:30 pm WST] Friday 15 April 2011
A Cyclone WARNING is current for coastal and island communities from Kuri Bay to
Kalumburu, in Western Australia.
At 12:30 pm CST [11:00 am WST] Tropical Cyclone Errol, Category 1 was estimated
to be 120 kilometres north of Troughton Island and 185 kilometres north
northwest of Kalumburu, moving west at 2 kilometres per hour parallel to the
coast. The cyclone may intensify further as it moves away from the Kimberley
coast early on Saturday.
GALES with gusts to 110 kilometres per hour may develop on the coast between
Kalumburu and Kuri Bay during today if the cyclone takes a more southwest track.
HEAVY RAIN is expected to cause flooding in the far north Kimberley.
FESA-State Emergency Service advises of the following community alerts:
BLUE ALERT: People in or near the communities between Kalumburu and Kuri Bay
should start taking precautions.
Details of Tropical Cyclone Errol at 12:30 pm CST [11:00 am WST]:
.Centre located near...... 12.7 degrees South 126.1 degrees East
.Location accuracy........ within 55 kilometres
.Recent movement.......... towards the west at 2 kilometres per hour
.Wind gusts near centre... 100 kilometres per hour and INTENSIFYING
.Severity category........ 1
.Central pressure......... 996 hectoPascals
Please ensure that neighbours have heard and understood this message,
particularly new arrivals or those who may not fully understand English.
The next advice will be issued by 5:00 pm CST Friday 15 April [3:30 pm WST
Friday 15 April].
This advice is available on telephone NT-1300 659 211 and WA-1300 659 210
DARWIN Tropical Cyclone Warning Centre

TROPICAL CYCLONE (TC) 21S (TWENTY-ONE) LOCATED APPROXIMATELY 270 NM
WEST OF DARWIN, AUSTRALIA, HAS DRIFTED SOUTH-SOUTHWESTWARD AT 02
KNOTS DURING THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS A WELL-DEFINED LOW LEVEL CIRCULATION CENTER (LLCC)
WITH DEEP CONVECTIVE BANDING ALONG THE SOUTHERN AND WESTERN
PERIPHERIES. A 14/2208Z SSMIS 91H MICROWAVE SATELLITE IMAGE SHOWS
SPIRAL BANDING AND DEEP CONVECTION WRAPPING AROUND THE LLCC. THERE
IS HIGH CONFIDENCE IN THE CURRENT POSITION BASED ON THE
AFOREMENTIONED MICROWAVE IMAGE. THE CURRENT INTENSITY IS BASED ON
PGTW, KNES, AND ADRM DVORAK INTENSITY ESTIMATES RANGING FROM 30 TO
45 KNOTS. OBSERVATIONS FROM TROUGHTON ISLAND, JUST SOUTH OF THE
LLCC, INDICATE 1008.8 MB MSLP WITH MAX WINDS AT 28 KNOTS, GUSTING TO
36 KNOTS (15/00Z). MSLP AT TROUGHTON HAS SHOWN A 1.3 MB PRESSURE
DROP OVER THE PAST 24 HOURS. THE LLCC REMAINS LOCATED BENEATH THE
RIDGE AXIS IN A REGION OF LOW VERTICAL WIND SHEAR AND STRONG
DIFFLUENCE ALOFT. ANIMATED WATER VAPOR IMAGERY CONTINUES TO SHOW
INCREASED POLEWARD AND EASTWARD OUTFLOW AS A MID-LATITUDE TROUGH
PASSES TO THE SOUTH. THE SYSTEM IS CURRENTLY IN A WEAK STEERING
ENVIRONMENT, BUT IS EXPECTED TO BEGIN TRACKING WEST-NORTHWESTWARD
DURING THE NEXT 12-24 HOURS UNDER THE INFLUENCE OF A MID-LEVEL
STEERING RIDGE BUILDING OVER WESTERN AUSTRALIA. THIS SYSTEM IS
EXPECTED TO REACH A PEAK INTENSITY OF 55 KNOTS WITHIN 24 HOURS AND
MAINTAIN INTENSITY THROUGH TAU 72 UNDER FAVORABLE ENVIRONMENTAL
CONDITIONS (LOW VERTICAL WIND SHEAR AND HIGH SST) BEFORE
ENCOUNTERING A DRY, HIGH-SHEAR ENVIRONMENT WEST OF 120E. MODEL
GUIDANCE IS IN FAIR AGREEMENT WITH THE EXCEPTION OF WBAR WHICH
TRACKS THE SYSTEM INLAND INTO THE SUBTROPICAL RIDGE. THIS FORECAST
IS WITHIN THE AIDS ENVELOPE AND IS SLIGHTLY FASTER THEN CONSENSUS TO
ACCOUNT FOR THIS MODEL ERROR. THIS WARNING SUPERSEDES AND CANCELS
REF A, NAVMARFCSTCEN 142121Z APR 11 TROPICAL CYCLONE FORMATION ALERT
(WTXS21 PGTW 142130). MAXIMUM SIGNIFICANT WAVE HEIGHT AT 150000Z IS
12 FEET. NEXT WARNINGS AT 151500Z AND 160300Z.//