Question 167-1 : Refer to the diagram assuming the usual direction of movement where will this polar frontal wave have moved 260 ? [ Formation assignment ]

Question 167-2 : What is the classification of the airmass affecting position 'q' at 0600 utc 261 ?

Tropical maritime.

455

Question 167-3 : In which of the following regions does maritime polar air originate ?

East of greenland.

A polar maritime air mass originates over the northern part of the north atlantic ocean east of greenland it is unstable cool and moist air and can produce anything from cumulus to cumulonimbus with showers and sunny spells in between 611

Question 167-4 : In which of the following situations can freezing rain be encountered ?

Ahead of a warm front in the winter.

505freezing rain is encountered ahead of a warm front in winter and in summer and sometimes behind a cold front

Question 167-5 : How do air masses move at a warm front ?

Warm air overrides a cold air mass.

505in a warm front warm air overrides a cold air mass

Question 167-6 : What type of precipitation would you expect at an active unstable cold front ?

Showers associated with thunderstorms.

614an air mass is unstable when an ascending parcel of air continues to rise to a considerable height eg cb an unstable air mass will normally be characterised by cumuliform cloud and good visibility except in precipitation

Question 167-7 : What is the relative movement of the two air masses along a cold front ?

Cold air pushes under a warm air mass.

621along a cold front the cold air pushes the warm air up

Question 167-8 : What cloud cover is typical for a wide warm sector of a polar front depression over central europe in the summer ?

Fair weather cu.

In a wide warm sector in summer over land you will have fair weather cumulus in winter you will have stratus mist and drizzle 516

Question 167-9 : Which of the following describes a warm occlusion ?

The coldest air mass is ahead of the original warm front.

With a warm occlusion cold front rides up and over the warm front 639 626in a warm occlusion the wedge of warm air from a warm sector depression is pushed up by the fast moving cold front and carried along aloft as the depression moves

Question 167-10 : When do cold occlusions occur most frequently in europe ?

Summer.

Over europe we get more warm occlusions in the winter and more cold occlusions in the summer

Question 167-11 : In which main direction does a polar front depression move ?

Along the front towards the east.

Depressions affecting western europe develop over the atlantic where cold polar air meets warm tropical air then moves east steered by the strong winds aloft this boundary is known as the polar front as show in this picture 517

Question 167-12 : What change in pressure will occur at point a during the next hour 263 ?

A rise in pressure.

518as the cold front moves away the barometer starts rising

Question 167-13 : What is the most likely cause of a lack of clouds at higher levels in a stationary high ?

Sinking air.

500with convergence aloft and divergence at the surface sinking air will dissipate cloud

Question 167-14 : The front labelled 'z' is a 279 ?

Warm front.

Question 167-15 : What is the speed of the front located over france 284 ?

15 kt.

645

Question 167-16 : How are the air masses distributed in a cold occlusion ?

The coldest air mass behind and the less cold air in front of the occlusion the warm air mass is above ground level.

537cold front 'lifts' the warm front up and over the very cold air

Question 167-17 : What characterizes a stationary front ?

The surface wind usually has its direction parallel to the front.

A stationary front forms when a cold front or warm front stops moving this happens when two masses of air are pushing against each other but neither is powerful enough to move the other winds blowing parallel to the front instead of perpendicular can help it stay in place 538a stationary front may stay put for days if the wind direction changes the front will start moving again becoming either a cold or warm front or the front may break apartthe weather is often cloudy along a stationary front and rain or snow often falls especially if the front is in an area of low atmospheric pressureon a weather map a stationary front is shown as alternating red semicircles and blue triangles the blue triangles point in one direction and the red semicircles point in the opposite direction

Question 167-18 : In an intense trough of low pressure over iceland during wintertime the weather likely to be experienced is ?

Strong wind shear convection and snow showers.

With a trough of low pressure over iceland and due to the coriolis effect a consequence of the earth's rotation this in turn gives rise to a strong flow of cold air from greenland which imply below normal temperatures in western greenland and over iceland the weather likely to be experienced is strong wind shear convection and snow showers in winter

Question 167-19 : Where are you likely to find the strongest winds close to the ground ?

In the transition zone between two air masses.

At the centre of a low pressure system a low or at the centre of a high pressure system a high and over area where there is little pressure gradient little variation in pressure over a large area winds are very lighton the other hand in the transition zone between two air masses at a warm front or a cold front you will find the strong winds close to the ground

Question 167-20 : An aircraft flying in the southern hemisphere at 2000 feet has to turn to the right in order to allow for drift in which direction relative to the aircraft is the centre of low pressure ?

In front.

If you need to turn right to counteract the wind because you are drifting left the wind is coming from your rightif you stand with your back to the wind in the northern hemisphere low pressure is on your left buys ballot's law northern hemisphere 542so in the southern hemisphere if you stand with your back to the wind low pressure is on the rightthe wind is coming from your right so the centre of low pressure is in front of the aircraft

Question 167-21 : Between which latitudes are you most likely to find the subtropical high pressure belt ?

25° 35°.

584

Question 167-22 : 'after such a fine day the ring around the moon was a bad sign yesterday evening for the weather today and sure enough it is pouring down outside the clouds are making an oppressively low ceiling of uniform grey but at least it has become a little bit warmer'which of these weather phenomena is being ?

A warm front.

622the ring around the moon halo is caused by the cirrus of the warm front

Question 167-23 : What will be the effect on the reading of an altimeter of an aircraft parked on the ground during the period following the passage of an active cold front ?

It will have decreased.

If for example your altimeter was set to 1020 hpa and indication was 500 ft after the passage of the cold front the pressure will increase your altimeter remained at 1020 hpa now shows less than 500 ft

Question 167-24 : What will be the effect on the reading of an altimeter of an aircraft parked on the ground shortly before an active cold front passes ?

It will be increasing.

Take an example parked on the ground your altimeter subscale setting is 1020 hpa and indicated altitude is 0 ftshortly before the active cold front passes the pressure will begin to fall for your altimeter it is similar as a gain of alitudeyou will see an altitude increase 518

Question 167-25 : What will be the effect on the reading of an altimeter of an aircraft parked on the ground as an active cold front is passing ?

It will first increase then decrease.

As the active cold front is passing the pressure will reduced thus the altimeter will show an increase in altitudeafter the cold front surface pressure increases thus the reading of the altimeter will show a decrease

Question 167-26 : Which of the following best describes zone a 299 ?

Trough of low pressure.

546

Question 167-27 : Which of the following best describes zone b 299 ?

Col.

546

Question 167-28 : Which of the following best describes zone c 299 ?

Ridge of high pressure.

546

Question 167-29 : Which of the following best describes zone d 299 ?

Depression.

546

Question 167-30 : At which airport is the following weather development taking place taf 231200z 231322 24014g32kt 4000 +tsra sct005 bkn015 bkn020cb becmg 1416 29012kt 9999 bkn030tcu sct100 tempo 1619 8000 shra bkn025tcu becmg 1922 27012kt 9999 sct030 ovc220 = 302 ?

Einn.

The taf starts at 1300z with surface wind from south west 14 kt gusting 32 kt and heavy thunderstorm and rain typical of cold front conditionsthe change between 1400z and 1600z indicates the passage of the cold front and cold sector polar maritime conditions good visibility cumulus cloud and the odd showerthe chart shows the situation at 1500z and it has just gone through einn that's looking about right the stations in switzerland lszh zurich airport and sweden essa stockholm airport are well clear of any frontal activity so it can't be any of themat 1300z the fronts would be to the west of the scandinavian stations and from the alignment of the isobars we would expect the surface wind to be southerly furthermore the fronts won't hit essa until some time after 1500z so we can rule that one out ekch will go into warm sector conditions tropical maritime poor visibility and possible stratus we are left with engm and the surface wind directions in the taf don't tie in with the isobars

Question 167-31 : Which of the following weather conditions would be expected at athens airport lgat at around 1450 utc 302 ?

21002kt 6000 br sct040 2916 q1026 nosig =.

Isobars are well spaced it means no or low wind this gives us two possible optionsin may at athens in the afternoon temperature might easily rise up to more than 25°c we have anticyclonic conditions with stable air moderate visibility and heating will raise the cloud base and dissipate some of the cloud

Question 167-32 : This chart shows the weather conditions on the ground at 0600 utc on may 4 which of the following reports reflects weather development at geneva airport 314 ?

Taf lsgg 040716 23016kt 8000 ra bkn030 ovc070 becmg 0810 5000 ra bkn020 ovc050 tempo 3000 +ra bkn010 ovc030 becmg 1215 25014kt 8000 sct030 bkn090 =.

A warm front is approaching 505as the front is approaching the cloud base gets lower bkn030 ovc070 > bkn020 ovc050 > bkn010 ovc030 the visibility decreases 8000m > 5000m > 3000m and the rain increases ra ra +ra after the warm front the wind turns slightly following the direction of the warm sector isobars visibility increases and the cloud breaks up

Question 167-33 : In zurich during a summer day the following weather observations were taken 160450z 23015kt 3000 +ra sct008 sct020 ovc030 1312 q1010 nosig =160650z 25008kt 6000 sct040 bkn090 1814 q1010 rera nosig =160850z 25006kt 8000 sct040 sct100 1915 q1009 nosig161050z 24008kt 9999 sct040 sct100 2115 q1008 nosig ?

A warm front passed the station early in the morning and a cold front during late afternoon.

Question 167-34 : On an aerodrome when a warm front is approaching ?

Qfe and qnh decrease.

When a warm front is approaching the surface pressure decreasesif the qfe was 1000 hpa and qnh 1020 hpa they will become qfe 990 hpa and qnh 1010 hpa for example your altimeter will show an increase of the indicated altitudeafter the warm front in the warm sector surface pressure will remain unchanged and when the cold front will be there surface pressure increase your altimeter will show a decrease of the indicated altitude

Question 167-35 : An observer on the northern hemisphere is under influence of the wind system of a depression which is moving from west to east the centre of the depression passes to the south of the observerfor this observer the wind direction is ?

Continuously backing.

We are in the northern hemisphere around the depression low wind turns counterclockwisethe observer is north of the depression he sees the wind coming from the south to go north by passing eastthe centre of the depression passes to the south of his position he sees the wind coming from east going to west by passing north for him the wind direction is continuously backing 627

Question 167-36 : In a warm front occlusion ?

The warm air is lifted.

With a warm occlusion cold front rides up and over the warm front the warm air is lifted 512

Question 167-37 : An air mass is unstable when ?

An ascending parcel of air continues to rise to a considerable height.

Question 167-38 : An air mass is stable when ?

Lifted air returns to its original level.

Question 167-39 : The weather most likely to be experienced at position 'r' is 326 ?

Fine and warm at first ac castellanus and cb in late afternoon with thunderstorms.

It's summer time over england few isobars and we are between low and high pressurenot much wind we do not expect any front over our position for the next hours most probably weather will be convective activity nice for the gliders this could produces ac castellanus and cb in late afternoon with thunderstorms

Question 167-40 : An occlusion has the characteristics of a warm front when ?

The cold air behind is warmer than the cold air ahead.

You have cool air behind and cold air ahead 512with a warm occlusion cold front rides up and over the warm front the warm air is lifted