MET kafli 15-19 Flashcards
Ice accumulates more readily on thick/thin wings.
Thin
Freezing fog exists if fog droplets are..
supercooled
What severity of icing will you have in Alto clouds?
Light-moderate
In what temperature will you have the worst icing?
-15°C
In what clouds could you find mixed ice?
NS (Nimbostratus)
Hvað þýðir það ef þú sérð ice pellets á jörð?
Indication of significant icing at altitude.
Mediterrenean front develops in what season?
Winter
What are typical clouds of a warm sector of a depression during winter?
Stratus
Hvernig ský myndast þegar þú hefur:
A) Heit jörð og kalt loft
B) Köld jörð og heitt loft
A) Cumuliform clouds (kalt loft hitnar og verður unstable)
B) Stratiform clouds.
Where does Polar Maritime airmass come from and what are it’s characteristics?
North Atlantic. Kemur yfir heitara yfirborð og verður unstable. RH high, good visibility
Polar Continental, hvernig er stability, humidity og warmth? Hvaðan kemur það?
Stable cold and dry. Kemur frá Siberu. Little clouds, excellend visibility.
What airmass can form Polar lows?
Arctic
What is the coldest airmass?
Polar Continental
Where does the Arctic airmass come from?
Polar Cap
Hvernig er stability í Arctic airmass?
Extremely unstable. (Það er mjög kalt og kemur yfir heitan sjó sunnar.)
What airmass is the most common to affect Europe?
Tropical maritime
Hvernig eru ský í “Returning polar maritime”
Cloudy, Cu/Cb, unstable
What airmass is responsible for the highest temperatures?
Tropical continental
What airmass originates from the Southern Balkan region?
Tropical continental
How are clouds and visibility in tropical maritime airmass?
Low clouds, low visibility
Where does the Tropical Maritime originate?
Mid-Atlantic around the Azores.
Á hvaða latitude myndir þú finna Polar front depression?
15° - 70°
Frá hvaðan í vestri til austurs er “mean position of polar front”
Frá Florida til suðvestur Englands.
Hvernig visibility myndir þú hafa í týpísku sumri í Evrópu með maritime Tropical warm?
5-10km
Nefndu fjóra “semi permanent fronts”
Polar front, Arctic front, ITCZ (intertropical convergence zone), Mediterrenean front
What kinds of clouds would you find “in the middle” í cold occlusion?
Altocumulus. Ef þú ert með NS þá er risk of CB.
Hvenær árs er cold occlusion líklegt?
Um sumar
Ef þú berð saman warm occlusion og cold occlusion, hvort hefur meira rain og hvor hefur meiri gusts
Cold occlusion hefur meiri rain og gusts
Áður en cold front nær warm front og það verður occluded front þá er space á milli frontanna. Hvernig eru skýjin þar?
6-8 Stratocumulus og Stratus
Atmospheric pressure of a polar front depression is lower in winter or summer?
lower in winter
How does the wind blow in a polar front depression?
Parallel to isobars. Blows along the front towards the east. (In the direction of the warm sector isobars).
What kind of weather would you have in a area affected by the passage of a polar front depression?
Continuous snow and rain. Then it stops to be followed by showers of rain and snow.
Eru vindar að veera/backa í polar front depression í upper og svo lower level?
Upper: veer
lower: back
Hvað finnur þú á milli tveggja polar front depressions?
Cold temporary anti-cyclone
When a warm front passes over a spot surface wind backs/veers and increases/decreases. What happens to precipitation?
Surface wind veers and increases
Í polar front depression, hvernig er loftið á milli warm front og cold front?
mTw
Í polar front depression, hvernig er veðrið á milli warm front og cold front? Precipitation and clouds
The precipitation is light rain og drizzle and in the summer you will have fair weather cumulus and in the winter you will have low stratus clouds.
How much time will you have between polar front depressions?
1-2 days.
Does wind veer or back when a warm front is passing?
veers
After a warm front has passed, what happens to temperature in the area?
Gets warmer
In a warm front, how big is the area where you can expect precipitation before the front?
200 - 300 NM
What is the slope of a warm front?
1:150
Why are clouds low in a warm front?
The low cold air (in the cold mass) gets saturated by the warm rain falling from above.)
What type of fog could you have in a warm front?
Frontal fog and advection fog.
Before a cold front arrives, what happens to pressure?
Pressure drops
How are winds while a cold front passes?
Gusty
What is the weather like after a cold front has passed
Colder, better visibility, increased pressure.
What kind of a front is this: “cold air is being replaced by warm air”?
Warm front
What cloud sequence could you see in a warm front (from the first clouds you see to the last)
Ci, Cs, As, Ns, St
Rapid movement of surface fronts can be caused by upper/lower winds blowing parallel/across the front
Upper winds blowing across the front
What happens to pressure when a cold front is approaching?
Pressure drops
Hvað gerist fyrir vind eftir cold front?
It veers
Á hvað stóru svæði er main precipitation í cold front?
50 - 100 NM
Hver er hallinn á cold front?
1:80
Hvað er annað nafn yfir orographic low?
Lee low
Hvað getur orographic low varað lengi?
2 klst en jafnvel upp í nokkra daga
In what situation will a heat low form and what is the weather like?
Forms over land in summer. There will be heavy precipitation, hail, turbulence, icing, wind shear, poor visibility).
What is the low called cold air moves over warmer sea?
Polar low
In what situation will a turbulence cloud form?
Warm maritime air blows over cold earth, it condenses and forms a fog, if there is a little bit of a wind the fog will lift and become low clouds called turbulence clouds.
Þegar þú færð Föhn effect, ertu aðstæður stable eða unstable?
Stable, annars myndi loftið bara halda áfram að rísa í stað þess að fara yfir hæðina og verða heitt.
What is the low called which often forms off the coast of Norway in winter?
Polar low
How strong can Tropical revolving storm surface winds be?
more than 65 kts.
what is the radius of a tropical revolving storm?
300 - 1500 km
Hvað kallast tropical revolving storm í Atlantic, east pacific (USA) og hvaða tíma árs myndast þetta?
Hurricane, summer and autumn
What is the most frequent and most intense Tropical revolving storm?
The typhoon
Hvað kallast tropical revolving storm í Indian ocean og hvenær er þetta?
Cyclone, may - november
Hvað heitir tropcical revolving storm sem myndast í western north pacific?
Typhoon
On what sides of oceans do storms form?
Eastern
How much % of “spiralling winds” turns into a storm?
10%
On what latitude can storms appear?
5° - 25°
How high must sea temperature be and how deep down, for storms to be able to appear?
26°C, 200-300 ft down.
the storm follows upper/lower wind cyclones?
Upper
A tropical storm has three stages, what is the windstrength like in these stages?
- tropical depression: 20-34 kts
- Tropical storm: 34-64 kts
- Fully mature hurricane: 64 kts
Secondary depression forms on a warm/cold front and tends to move round the primary/secondary in a cyclone/anticylonic sense.
cold, primary, cyclonic
What is wind strength like in the eye of a tropical revolving storm?
20-50km
What is happening if the eye tightens on a tropical revolving storm?
Storm is intensifying.
In a tropical revolving storm, where pressure is lowest the wind is ..
calmer
How long does a tornado last?
It can last a few minutes up to a few hours. Typical is a few minutes to 30 minutes.
What is the highest windstrength for a tornado ever recorded and where in the tornado was it recorded?
200 kts in center.
What is the usual windstrength of a tornado?
20 - 40 kts.
What is the diamter of a tornado?
100 m - 150 m
At what time do tornados typically appear? When do they peak?
14:00 - 22:00. Peaks at 17:00.
What is the tornado “high season” ?
spring and early summer.
The West African Tornado (WAT) is a line squall caused by _____
atmospheric waves
What happens to wind direction and speed after the passage of a warm front?
Wind veers and speed decreases.
In central Europe, what cloud cover could you expect in the warm sector of a depression during winter?
St
Between two airmasses you can see the forming of frontal ____ pressure
low
When a warm front is coming what will happen to pressure and temperature? What happens after it has gone?
Before: pressure drops, temperature is cool.
After: Pressure rises then falls and tmeperature increases
When a warm front is coming what will happen before to the wind and what will happen after it passes?
First it wall back and then when it passes it will veer (and windstrength will decrease)
When a cold front is coming what will happen before to the pressure and then afterwards? How about temperature?
It will drop, then increase as it passes. Held að það sé klárlega kaldara eftir cold front.
Arctic front er boundary á milli ___ air og ___ air.
polar air og arctic air.
A stationary front has no _____ motion perpendicular to the front.
horizontal
In an anti-cyclone, subsidence causes ___ air and an convergence/inversion
dry air, causes inversion.
In the northern hemisphere, advection of warm air aloft indicates..
the coming of a warm occlusion
