Weather Information Flashcards
What are the types of AIRMETS?
Sierra (IFR or Mountain), Tango (Turbulence), Zulu (Icing)
Conditions for AIRMET Sierra ?
Ceilings < 1000 AGL and/or < 3 SM Visibility over 50% of area.
Conditions for AIRMET Tango ?
Moderate Turbulence OR sustained surface winds > 30 KTS
Conditions for AIRMET Zulu ?
Moderate icing or freezing levels
What are SIGMETS ?
Similar to AIRMETS with more severe Wx
What are the conditions for SIGMETS ?
Severe or greater over a 3000 sq mile area:
1) Turbulence
2) Icing
3) IMC due to dust, sand or volcanic ash
What conditions are convective SIGMETS issued ?
1) An area of TS affecting 3000 sq miles or greater with TS affecting at least 40% of the area
2) A line of TS at least 60 NM long with TS affecting 40% of the length
3) Severe or embedded TS affecting any areas that are expecting to last for 30 minutes or more
How many times a day are AIRMETS issued ?
4
What time of day are AIRMETs issued ?
0245, 0845, 1425, 2045 Zulu
How long are AIRMETS valid for?
6 hrs
Are SIGMETS issued on a regular schedule ?
No. When conditions are met.
What times are convective SIGMENTS issued ?
55 min past each hour.
What conditions are needed for a special convective SIGMET ?
Any of the following for more than 30 min:
1) Tornado
2) Hail 3/4 inch
3) Gust > 50 KTS
4) Rapidly changing Wx
How long are convective SIGMETS valid for ?
Up to 2 hrs or the next issuance.
List 3 types of Hydroplaning ?
All keep tire from surface contact.
Dynamic (Lifting)
Viscous (Slipping)
Reverted Rubber (Steam Lift)
Conditions for Dynamic Hydroplaning ?
Most common Higher speed Heavy water layer Water Pressure creates wedge and lifts Rubber does not touch surface Affected by Tire Pressure
Conditions for Viscous Hydroplaning ?
Thin water/oil/rubber on service
Tire can’t penetrate to surface
Slower Speed
Smooth service/Asphalt
Conditions for Reverted Rubber Hydroplaning
Water layer
Heavy prolonged braking
Rubber melts and heats water to steam
Steam Lifts tire from surface.
What are the types of Fog ?
Radiation (most Common)
Advection (beach fog)
Upslope fog
Steam Fog
How does Fog form ?
Cold airmass moving into Warm, Moist Air
How does Radiation Fog Form ?
Cold Air moves for warm, moist ground surface
How does Advection Fog form ?
Needs wind. Cold Air moves for warm, moist Water
Summer:
Cold Air over Water Moves inland over Warmer Land.
Winter:
Cold Air over Land moves out over Warmer Water.
How does upslope Fog form ?
Warm/Cold Air Mass pushed up/down slop into Warm/Cold Air.
How does Steam Fog form ?
Evaporation occurs into cold air over warmer water.
Air is much colder than water for convection
Created Shallow layer.
