Agro-Meteorological Bulletin for the Second Dekad (11th - 20th) of August, 2020



ISSUED AT: 07:53 AM

Date: Tuesday 11th of August 2020

Figure 1.

Figure 2.

Summary:

During the second dekad of August 2020, relatively wet days are expected on the 12th, 15th, 17th and 20th; while wet days are expected on the 11th, 13th, 14th, 16th, 18th and 19th. On relatively wet days expect intermittent cloudy patches with a moderate probability (55%) of brief showers and on wet days expect cloudy periods with a moderate probability (70%) of light to moderate showers.


Agro-Meteorological Bulletin for the Second Dekad (11th - 20th) of August, 2020



ISSUED AT: 07:53 AM

Date: Tuesday 11th of August 2020


Definitions used in the forecast and bulletin:

Term Meaning
Dekad 10 day rainfall measuring period
Rain Day A day with 1.0 mm or more of rainfall amount
Wet Day A day with 10.0 mm or more rainfall amount
Extremely Wet Day A day with 25.0 mm or more of rainfall amount
Normal Rainfall Between 75% and 125% of the average
Below Normal Rainfall Rainfall below 75% of the average
Above Normal Rainfall Rainfall in excess of 125% of the average
Much Below Normal Rainfall Rainfall below 50% of the average
Much Above Normal Rainfall Rainfall above 150% of the average
Scanty Rainfall Less than 1 mm
Moderate Rainfall 1-10 mm
Heavy Rainfall 10-50 mm
Very Heavy Rainfall Greater than 50 mm
Probability of 1-30 % Low Chance
Probability of 30-70 % Moderate Chance
Probability greater than 70 % High Chance
Term Amount of Rain Type of day
Scanty Rainfall Less than 1 mm Relatively dry day
Moderate Rainfall 1-10 mm Relatively wet day
Heavy Rainfall 10-50 mm Wet day
Very Heavy Rainfall Greater than 50 mm Excessively wet day

Weather Assessment for the period (1st –9th) of August 2020.

During the period 1st to 9th of August, mostly wet days occurred over Trinidad and Tobago. These wet days were due to the passage of tropical waves and a visitation of the Inter Tropical Convergence Zone. There were preliminary reports of flooding in northwestern Trinidad in areas such as Diego Martin. Rainfall totals’ maps for the period 1st to 9th of August are located below as figure 1 and figure 2.

 

Figure 1. Rainfall map of Trinidad showing measured rainfall totals for varying districts during period 1st to 9th of August 2020.

 

Figure 2. Rainfall map of Tobago showing measured rainfall totals for varying districts during period 1st to 9th of August 2020.

 

The observed temperatures (maximum/minimum), average relative humidity (maximum/minimum) and long-term 10-day (10dys) averages for Piarco International Airport and ANR Robinson International Airport during first dekad of August 2020.

Location

Maximum Temperature

0C/ Long term 10 dys average 0C

Minimum Temperature

0C /Long term 10 dys average 0

Average maximum Relative humidity

(%)/ Long term 10 dys average (%) 

Average minimum Relative humidity

(%)/Long term 10 dys average (%) 

Trinidad (Piarco International airport)

33.7/31.9

(1981-2010)

23.2/23.6

(1981-2010)

90/93

(1990-2010)

78/70

(1990-2010)

 

Tobago (ANR Robinson International airport)

32.9/30.8

(1981-2010)

24.4/24.4

(1981-2010)

89/91

(1990-2010)

71/69

(1990-2010)

 

Table 1 shows the expected weather conditions during the Second Dekad (11th –20th) of August 2020, for Trinidad and Tobago.

Table 1.

Days:

Expected weather:

11th     

Cloudy periods with a moderate probability (70%) of light to moderate showers.

12th

Intermittent cloudy patches with a moderate probability (55%) of brief showers.

13th

Cloudy periods with a moderate probability (70%) of light to moderate showers.

14th

Cloudy periods with a moderate probability (70%) of light to moderate showers.

15th

Intermittent cloudy patches with a moderate probability (55%) of brief showers.

16th

Cloudy periods with a moderate probability (70%) of light to moderate showers.

17th

Intermittent cloudy patches with a moderate probability (55%) of brief showers.

18th 

Cloudy periods with a moderate probability (70%) of light to moderate showers.

19th

Cloudy periods with a moderate probability (70%) of light to moderate showers.

20th

Intermittent cloudy patches with a moderate probability (55%) of brief showers.

 

Table 2 shows the expected temperatures, humidity and dust haze days during the second dekad of August for Piarco, Trinidad.

Table 2.

Day

Maximum Temperature

0C

Minimum Temperature

0C

Average Relative humidity (%)

Dust Haze

Yes/No

11th

31.0

23.0

90

No

12th 

33.0

22.0

80

Yes

13th

31.0

24.0

90

No

14th

31.0

24.0

90

No

15th

33.5

22.7

70

Yes

16th

31.0

23.5

90

No

17th

33.9

24.0

75

Yes

18th  

31.0

24.0

90

No

19th

31.0

24.0

90

No

20th

33.5

23.8

75

Yes

 

Table 3 shows the expected temperatures, humidity and dust haze days during the second dekad of August for the ANR Robinson, Tobago.

Table 3

Day

Maximum Temperature

0C

Minimum Temperature

0C

Average Relative humidity (%)

Dust Haze

Yes/No

11th

31.0

23.0

90

No

12th 

32.0

22.0

80

Yes

13th

31.0

24.0

90

No

14th

31.0

24.0

90

No

15th

32.9

22.7

70

Yes

16th

31.0

23.5

90

No

17th

32.9

23.0

75

Yes

18th  

31.0

24.0

90

No

19th

31.0

24.0

90

No

20th

32.9

23.8

75

Yes

 

Trinidad’s Mean Daily Rainfall Forecast for the second Dekad of August (11th -20th) 2020.

Northern & Northwestern areas:

Moderate chance (65%) of mean daily rainfall up to 8.9 mm.

North-Eastern and Eastern areas:

Moderate chance (68%) of mean daily rainfall up to 12.6 mm.

Central, West-Central and inland areas:

Moderate chance (60%) of mean daily rainfall up to 6.4 mm.

South-Eastern areas:

Moderate chance (68%) of mean daily rainfall up to 12.8 mm.

Southern areas:

Moderate chance (65%) of mean daily rainfall up to 10.9 mm.

South-Western areas:

Moderate chance (65%) of mean daily rainfall up to 9.3 mm.

 

Figure 3. Rainfall map of Trinidad showing possible rainfall totals for varying districts during the second dekad of August 2020 and percentage probability of occurrence.

 

Tobago’s Mean Daily Rainfall Forecast for the Second Dekad of August (11th -20th) 2020.

Northeastern areas:

Moderate chance (68%) of mean daily rainfall up to 5.0 mm.

South-Western areas:

Moderate chance (68%) of mean daily rainfall up to 5.0 mm.

Figure 4. Rainfall map of Tobago showing possible rainfall totals for varying districts during the second dekad of August 2020 and percentage probability of occurrence.

 

Impacts on Agriculture:

During the second dekad of August 2020, relatively wet days are expected on the 12th, 15th, 17th and 20th; while wet days are expected on the 11th, 13th, 14th, 16th, 18th and 19th. There is a high (75%) probability that the anticipated rainfall will return significant soil moisture across Trinidad and Tobago. Due to the rainfall episodes of the last two consecutive dekads, rivers are likely to significantly increase in volume, water logged soils and pooling of water in low-lying areas are highly probable. Shrubs and grass-growth will continue at a fast pace. Additionally, with warm temperatures and routinely moist vegetation, there is a moderate (70%) probability for fungi spread, root rot, insects pests and warm weather diseases to develop.

Sun and Moon positions in the sky:

The sun is presently at a latitude of approximately 15.25 degrees North, and with this position, the day-length will 12.4 hours. As Trinidad and Tobago is in the heat and rainy seasons, regular cloud cover is possible, consequently, there is a moderate probability (60%) of intense solar radiation occurring during the second dekad of August 2020, when the sky is generally cloud free. There is also low probability (29%) of heat stress on young/sick/elderly animals from direct exposure to solar radiation and warm temperatures. Additionally, the moon’s third quarter phase will be on the 11th followed by new moon phase on the 18th of August 2020. As a result, there will be medium to low moon illumination over crop fields and livestock at night during the dekad.