AGROCLIMATIC INFORMATION FOR AGRICULTURAL PLANNING AND OPERATION IN ILOCOS NORTE PARTICULARLY BATAC AND SURROUNDING AREAS FOR THE MONTH OF JUNE

I. AGROCLIMATIC SUMMARY::

Generally cloudy skies with scattered to occasional rains is the normal weather in the area. Total rainfall amount averages 286.7 mm with 13 rainy days. Southwest monsoon rains prevail. Total evaporation of 153.8 mm are the normal values for the month.

Soil moisture is generally wet. Humid environment is felt during the month so drying condition is poor. Leaf wetness duration is from 6 to 12 hours. Daylight duration is 13 hours and 06 minutes with 45% total bright sunshine. This situation gives an amount of 19.9 MJ/m2of solar radiation during most days of the month. Southerly to southeasterly winds prevail.

The normal maximum air temperature is 33.1 °C. An extreme temperature of 36.0 °C was recorded on June 20, 1982. Minimum air temperature is 24.0 with an extreme coolness of 19.0 °C as what was recorded on June 18, 1977.

II. AGROCLIMATIC DATA (AVERAGE)::

Decade Rainfall Rainy P(W)* P(TC)** Tot AIR TEMPERATURE RH Solar Wind
(10 Day) (mm) days % % evap. Max. Min. (%) Rad. Speed
          (mm) (°C) (°C)   MJ/m2 (kpd)
June                    
1-10 96.2 4 55 10 53.1 33.2 23.9 81 20.0 47.3
11-20 70.3 4 60 14 52.5 33.3 24.1 81 19.9 42.6
21-31 120.2 5 65 33 48.2 32.9 24.1 82 19.7 47.8

Ten-day rainfall depth at different probability levels for June in Batac, Ilocos Norte

Decade Mean Rainfall Probable rainfall depth
    25% 50%
1-10 96.2 87.0 15.6
11-20 70.3 76.0 3.4
21-31 120.2 95.9 13.6

* Probability of wet decade (>50 mm per decade)

** Probability of having a Tropical Cyclone

Initial probabilities that a given decade is dry (D) or wet (W) and transitional probabilities that one, two or three days within a decade is dry or wet.

June Initial
(%)
Transitional %
D W DD WD DW WW DDD WDD DWD DDW WWD WDW DWW WWW
1-10 45 55 25 75 55 45 2 4 20 10 14 26 14 10
11-20 40 60 14 86 58 42 2 11 13 4 10 23 21 16
21-31 35 65 33 67 38 62 6 12 13 6 23 12 10 18
DD -- probability of a dry day given that the previous day was dry
DW -- probability of a dry day given that the previous day was wet
WD -- probability of a wet day given that the previous day was dry
WW -- probability of a wet day given that the previous day was wet
DDD -- probability that three consecutive days are dry
WWW -- probability that three consecutive days are wet
WWD -- probability that two consecutive days are wet and the third day is dry
WDW -- probability that within three days the second day is dry

III. TROPICAL CYCLONE

Northern Luzon which includes Ilocos Norte is within the normal tropical cyclone track. Historical record shows the following tropical disturbances that crossed or passed closed over the area (1981-2006).

TC Name Year and Date Occurrence
TS Bining June 12-14, 1981
T Kuring June 18-21, 1981
T Kuring June 21-23, 1985
TD Bining June 1, 1988
TD Akang June 13-15, 1990
TS Bising June 21-22, 1990
T Klaring June 25-28, 1990
T Asiang June 24-28, 1992
TD Daling June 22-27, 1997
T Etang June 4-6, 1999
TS Helming June 21-25, 1999
TD Darna June 17-19, 2001
TS Emong June 21-23, 2001
TD Florita June 28-July 3, 2002
TS Egay June 13-18, 2003
TS Frank June 6-9, 2004
T Igme June 27-July2, 2004
TS Domeng June 24-26, 2006

RAINFALL DEPTH AT DIFFERENT PROBABILITIES OF OCCURRENCE FOR JUNE 1-30

DATE RAINFALL DEPTH (mm)
25% 50%
1 21.6 0
2 14.2 7.8
3 7.0 0
4 10.6 5.0
5 7.0 2.4
6 3.0 0
7 2.8 0
8 11.8 0.4
9 5.2 0
10 3.8 0
11 1.0 0
12 0.6 0
13 14.6 0
14 13.0 0.2
15 4.2 0
16 4.4 1.0
17 8.2 0.8
18 15.2 1.0
19 10.0 0
20 4.8 0.4
21 13.0 0.4
22 12.0 2.4
23 10.9 2.6
24 9.8 0
25 10.2 2.0
26 4.2 1.4
27 14.2 0.2
28 8.8 2.2
29 6.6 0.4
30 6.2 2.0

DAILY RAINFALL PROBABILITY (GRAPH)