Logo
Print

A. Cloud Description

 

SKY CONDITIONDEFINITION/DESCRIPTION

Clear or Sunny Skies

  • State of the sky when it is cloudless, totally clear or with a few small light clouds visible.
  • Has a total cloud cover of less than one okta.

Partly Cloudy

  • State of the sky is within 2-5 oktas total cloud cover or has between 30% to 70% cover of the celestial dome.

Partly Cloudy to at Times Cloudy

  • Mostly partly cloudy but there are times when more than 70% of the celestial dome is covered with clouds.

Mostly or Mainly Cloudy

  • The sky is mostly covered with clouds but with possible brief periods of sunshine.
  • The total cloud cover is between 6 to 8 oktas.

Cloudy

  • The sky is covered with clouds between 6 to 8 oktas or has more than 70% cloud cover.
  • Predominantly more clouds than clear sky.
  • For a longer period during the day, the sun is obscured by clouds.

Overcast

  • The sky is totally or completely covered with thick and opaque clouds, 8 oktas or around 100% cloud cover.

B. Precipitation (Rain & Rainshowers) Description

1. Rains

 

RAIN CLASSIFICATIONDEFINITION/DESCRIPTION

Very Light Rains

  • Scattered drops that do not completely wet an exposed surface regardless of duration.

Light Rains

  • The rate of fall is from trace to 2.5 mm per hour.
  • Individual drops easily identified and puddles(small muddy pools) form slowly.
  • Small streams may flow in gutters.

Moderate Rains

  • The rate of fall is between 2.5 mm to 7.5 mm per hour.
  • Puddles rapidly forming and down pipes flowing freely.

Heavy Rains

  • The rate of fall is greater than 7.5 mm per hour.
  • The sky is overcast, there is a continuous precipitation.
  • Falls in sheets, misty spray over hard surfaces.
  • May cause roaring noise on roofs.

Monsoon Rains

Other Descriptions:

  • Heavy and continuous precipitation attributed to either the Southwest or Northeast Monsoon.

Occasional Rains

  • Not frequent but is recurrent precipitation.

Widespread Rains

  • Precipitation occuring extensively throughout an area.

Frequent rains

  • Precipitation occuring regularly and often throughout the time duration.

Intermittent Rains

  • Precipitation which ceases at times and re-occur again.

 

2. Rainshowers

 

RAINSHOWERSDEFINITION/DESCRIPTION

Scattered Rainshowers

  • The rain-bearing clouds is distributed spatially resulting to rainshowers occuring to the bigger part of the forecasted area.

Isolated Rainshowers

  • The rain-bearing clouds is small and isolated resulting to rainshowers occuring only to a small part of the forecasted area.

Occasional Rainshowers

  • There is a large amount of convective clouds and precipitation occur in most parts of the forecasted area occasionally, and varying in rainfall amount.

Squally Rainshowers

  • Showers accompanied by brief but sudden strong or gale force winds.




C. Wind Description(Based from the Beaufort Wind Scale and the Saffir-Simpson Scale)

 

WIND DESCRIPTION

UNITS in KPH

UNITS in KNOTS

DESCRIPTION AS OBSERVED

Light Winds

19 or less

10 or less

  • Wind felt on face.
  • Ordinary wind vanes moved by wind.
  • Leaves rustle.

Moderate Winds

20-29

11-16

  • Wind raises dust and loose paper.
  • Small branches are moved.

Moderate to Occasionally Strong

   
  • Moderate winds mostly persist but there are instances during the forecast period that it reaches strong wind force.

 Fresh Winds*

30-39

17-21

  • Small trees in leaf begin to sway.
  • Crested wavelets appear on inland waters.
 Strong Winds 40-50 22-27
  • Large branches in motion.
  • Whistling heard in telephone wires.
  • Umbrellas used with difficulty.

Gale:

1 Near Gale*

2 Gale
3 Strong Gale*

 

51-62

63-75
76-87

 

28-33

34-40
41-47

 

  • Whole trees in motion.
  • Inconvenience felt when walking against wind.
  • Twigs break off road.
  • Cars veer on road.
  • Larger branches break off.
  • Slight structural damade occurs-roofing dislodged.

Stormy:

1 Storm

2 Violent Storm*

3 Typhoon*

 

88-102

103-117

118 or more

 

48-55

53-63

64 or more

 

  • Trees uprooted.
  • Considerable structural damage.
  • Widespread damage.
  • Widespread damage.




D. Sea Condition as affected by Wind Force (Based from the Beaufort Wind Scale)

 

WIND FORCEUNITS in (MPS)UNITS in (KTS)WAVE HT.(METERS)SEA CONDITION
 Calm 0-1.5 0-3.0 0.1
  • Ripples with the appearance of scales are formed but without foam crests.
 Smooth 1.5-4.0
 
3.0-8.0
 
0.1-0.5
 
  • Small wavelets, still short but more pronounced.

 

  • Crest have glassy appearance and do not break.
 Slight 4.0-8.0
 
8.0-16.0
 
0.5-1.25
 
  • Small waves, becoming longer.
  • Fairly frequent white horses.
 Moderate 8.0-11.0
 
16.0-22.0
 
1.25-2.5
 
  • Moderate waves taking a more pronounced long form.
  • Many white horses are formed-a change of some spray.
 Rough 11.0-16.0 22.0-32.0 2.5-4.0
  • Large waves begin to form.
  • Sea heaps up and white foam from breaking waves begin to be blown in streaks along the direction of wind.
 Very Rough 16.0-20.0

 
32.0-40.0

 
4.0-6.0

 
  • Moderately high waves of greater length.
  • Edges of crest begin to break into spindrift.
  • Foam is blown in well-mark streaks along the direction of the wind.
 High 20.0-26.0

 
40.0-52.0

 
6.0-9.0

 
  • High to very high waves with long overhanging crests.
  • The surface of the sea takes on white appearance.
  • The thumbling of the sea becomes heavy with visibility affected.
 Very High 26.0-34.0


 
52.0-68.0


 
9.0-14.0


 
  • Exeptionally high waves.
  • Small and medium size ships occasionally lost from view behind waves.
  • The sea is completely covered with long white patches of foam.
  • The edges of wave crest are blown into froth.
 Phenomenal >34.0

 
>68.0

 
>14.0

 
  • The air is completely filled with foam and spray.
  • Sea completely white with driving spray.
  • Visibility very seriously affected.