
This forecast map shows the storm depression which is expected to hit South Georgia tomorrow. Peak gusts of over 50 - 60 kt are likely - see forecast below
Aviation Forecast - South Georgia
Stromness - 10 March 2013 - made 10/0900utc
1. Synoptic situation
The main feature to look forward to is the storm depression which is expected to come across South Georgia tomorrow (11 March). At this stage this pressure system is explosively deepening somewhere to the North west of South Georgia and is expected to hit the Island during the day of tomorrow.
However today, the weather will be favorably determined by the mobile high pressure ridge, that is situated in between the depression that dominated the weather the las couple of days and the depression described above.
2. Weather conditions
Today the conditions are expected to improve during the day. So most of the low clouds should gradually disappear and some orographic stuff remains. After 21/24utc the high and mid level clouds associated to the storm depression will gradually invade the South Georgian skies and will continuously increase and the cloud bade will gradually lower.
Tomorrow mainly overcast with moderate snow/sleet turning into sleet/rain. No significant change until 21/24utc. Very high winds develop.
3. Clouds
-4-6/8 Stratus gradually dissipating and becoming orographic with sunny periods
-after 21/24utc increasing and thickening Cirrus/Cirrostratus and Altocumulus/Altostratus.
-after 11/06-09utc becoming 6-8/8 Stratus 1-1500ft and layers above.
4. Wind
10/12utc till 11/00utc: weak from variable directions tempo 150-170/5-10kt
11/00utc till 11/12utc: gradually increasing to become 100-120/15-20kt gust 30kt
11/12utc till 12/00utc: gradually further increasing with peak winds between 15-21utc: average 120-140/30-40kt gusting 50-60kt
5. Upperwinds - 1500ft
10/12utc till 11/00utc: 150-170/10-15kt
11/00utc till 11/12utc: becoming 120-140/25-30kt
11/12utc till 12/00utc: increasing tempo 130-150/50-60kt
6. Visibility
today mainly good.
tomorrow poor in mod to heavy sleet/snow
7.Hazards in flight
-icing: 0°C-isotherm is on the surface-tomorrow tempo mod to severe icing
-turbulence: today: none to weak-tomorrow: tempo mod to severe
9. General evolution for the next days
Tuesday 12/03/2013
weather: remainders of frontal depression with still some sleet. Still very cloudy but some short lived sunny spells develop.
wind: 140-160/25-30kt slowly decreasing
Wednesday 13/03/2013
weather: sunny, with patches of low clouds/fog
wind: Southerly sector veering to SW 10-15kt
Thursday 14/03/2013
weather: sunny, with patches of low clouds/fog
wind: SW 8-12kt
10. Remarks - Warning:
-valid for 12/12utc till 12/24utc: high wind speeds with peak gusts up to 60kt
11. Sunrise-Sunset (UTC)
10 Mar: Sunrise 8:08 Sunset 21:03
11 Mar: Sunrise 8:10 Sunset 21:01