Tropical Storm Bernard

Moderate Tropical Storm Bernard
Moderate tropical storm (MFR)
Tropical storm (SSHS)
Moderate Tropical Storm Bernard at peak intensity
Formed November 19, 2008
Dissipated November 21, 2008
Highest winds 10-minute sustained:
65 km/h (40 mph)
1-minute sustained:
75 km/h (45 mph)
Lowest pressure 994 mbar (hPa; 29.35 inHg)
Fatalities None reported
Damage None
Areas affected No land areas
Part of the 2008–09 South-West Indian Ocean cyclone season and the 2008–09 Australian region cyclone season

Moderate Tropical Storm Bernard (JTWC designation: 03S; BoM designation: 01U was a weak and short lived tropical cyclone which existed during mid-November 2008. The third tropical disturbance and second named storm of the 2008–09 South-West Indian Ocean cyclone season, Bernard developed out of a small area of low pressure on November 15 located about 795 km (495 mi) east-southeast of Diego Garcia. Traveling towards the east, the system gradually strengthened and was declared Tropical Disturbance 03-20082009 early on November 19. The disturbance strengthened into a depression the next day before briefly reaching moderate tropical storm status around 1200 UTC on November 20. As the system began to accelerate, convection associated with it rapidly diminished and the storm dissipated early the next morning.

Contents

Meteorological history

On November 15, the Joint Typhoon Warning Center (JTWC) began monitoring an area of low pressure accompanied by persistent convection located about 795 km (495 mi) east-southeast of Diego Garcia.[1] The low was centered to the east of an upper-level ridge axis within an area of moderate vertical wind shear.[1] With less than optimal conditions for development, the JTWC assessed the chances of the low developing into a tropical cyclone within 24 hours as "poor".[1] Over the next several days, the system moved slowly in a general eastward direction with little development.[2] On November 19, convection developed around the center of circulation after being nearly stationary for a few days. At 0600 UTC, the Regional Specialized Meteorological Centre for the southwest Indian Ocean, Météo-France, designated the system as Tropical Disturbance 03-20082009[3] while located about 695 km (430 mi) east-southeast of Diego Garcia.[2] As convective banding features and fair poleward outflow developed, the JTWC issued a Tropical Cyclone Formation Alert, stating that the disturbance was likely to develop into a tropical cyclone within 24 hours.[4]

Later that day, Météo-France upgraded the disturbance to a tropical depression, as winds had increased to 55 km/h (35 mph 10-minute winds). At this time, the maximum radius of tropical depression-force winds was 50 km (30 mi).[5] About three hours after being designated as a depression, the JTWC began issuing advisories on Tropical Cyclone 03S as they estimated winds to have reached 65 km/h (40 mph 1-minute winds). Although sea surface temperatures were supportive of development, moderate wind shear was forecast to prevent the system from significantly intensifying.[6] Located to the northeast of a low to mid-level trough and to the southwest of a near-equatorial ridge the system began to accelerate.[2] At 0600 UTC on November 20, the JTWC assessed the system to have reached its peak intensity with winds of 75 km/h (45 mph 1-minute winds) [7] while located 1,445 km (900 mi) west of the Cocos Islands.[2] Shortly after, Météo-France upgraded the depression to a moderate tropical storm and gave it the name Bernard. Upon being named, Bernard reached its peak intensity with winds of 65 km/h (40 mph) with a minimum pressure of 994 hPa (mbar).[8]

Just six hours after being named,[2] Bernard was downgraded to a tropical depression as all deep convection associated with the system dissipated.[9] The sudden decrease in convection was caused by the storms unusually fast movement of 50 km/h (31 mph) towards the east-southeast. In addition, the depression began moving over cooler sea surface temperatures, which would prevent a significant redevelopment of convection.[2] At the same time Météo-France downgraded Bernard to a depression, the JTWC issued their final advisory on Tropical Cyclone 03S as it had weakened below tropical storm status.[10] Early the next morning, Météo-France downgraded the system to a tropical disturbance and issued their final advisory on the dissipating cyclone.[11] As Météo-France issued their final advisory, the remnants of Bernard entered Tropical Cyclone Warning Center in Jakarta's area of responsibility and was designated as Tropical Low 01U. However, this was the only advisory issued by Darwin as the low dissipated shortly after[12] while located about 675 km (420 mi) west-northwest of the Cocos Islands.[2]

Impact

As Bernard remained out over open waters for the duration of its existence, there was no impact on any land-masses.[2][13]

See also

References

  1. ^ a b c "Significant Tropical Weather Advisory for the Indian Ocean 11-15-2008 00Z". Joint Typhoon Warning Center. http://www.webcitation.org/5cMH0lRLX. Retrieved February 8, 2009. 
  2. ^ a b c d e f g h Gary Padgett (February 3, 2009). "Monthly Global Tropical Cyclone Summary for November 2008". Australian Severe Weather. http://australiasevereweather.com/cyclones/2009/summ0811.htm. Retrieved February 8, 2009. 
  3. ^ "Tropical cyclone Warning 11-19-2008 06z". Météo-France. http://www.webcitation.org/5cRTr0lTP. Retrieved February 8, 2009. 
  4. ^ "WTXS21 11-19-2008 08Z". Joint Typhoon Warning Center. http://www.webcitation.org/5cReBNcyX. Retrieved February 8, 2009. 
  5. ^ "Tropical cyclone Warning 11-19-2008 18z". Météo-France. http://www.webcitation.org/5cSJ67pJe. Retrieved February 8, 2009. 
  6. ^ "WTXS32 11-19-2008 21Z". Joint Typhoon Warning Center. http://www.webcitation.org/5cSMXIOwL. Retrieved February 8, 2009. 
  7. ^ "WTXS32 11-20-2008 09Z". Joint Typhoon Warning Center. http://www.webcitation.org/5cTW2fOa2. Retrieved February 8, 2009. 
  8. ^ "Tropical cyclone Warning 11-20-2008 12z". Météo-France. http://www.webcitation.org/5cTVnaai0. Retrieved February 8, 2009. 
  9. ^ "Tropical cyclone Warning 11-20-2008 18z". Météo-France. http://www.webcitation.org/5cTqkearx. Retrieved February 8, 2009. 
  10. ^ "WTXS32 11-20-2008 21Z". Joint Typhoon Warning Center. http://www.webcitation.org/5cU1njVoU. Retrieved February 8, 2009. 
  11. ^ "Tropical cyclone Warning 11-21-2008 00z". Météo-France. http://www.webcitation.org/5cU6zmia2. Retrieved February 8, 2009. 
  12. ^ "High Seas Darwin 11-21-2008 00z". Australian Bureau of Meteorology. http://www.webcitation.org/5cU6ykuC9. Retrieved February 8, 2009. 
  13. ^ Gary Padgett (November 30, 2008). "Monthly Global Tropical Cyclone Tracks for November 2008". Australian Severe Weather. http://australiasevereweather.com/cyclones/2009/trak0811.htm. Retrieved February 8, 2009. 

External links

Tropical cyclones of the 2008–09 South-West Indian Ocean cyclone season
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Tropical cyclones of the 2008–09 Australian region cyclone season
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Australian Tropical Cyclone Scale
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