FIJI
METEOROLOGICAL
SERVICE
Private Mail Bag (NAP0351)
Nadi Airport, Fiji
Ph: +679 6724888
Fax: +679 6724050
Email: [email protected]
Also online at:
http://www.met.gov.fj
Issued: June 6, 2017
1.
Fiji Climate Summary
May 2017
Since : August 1980*
ISO 9001:2008
certified Climate
Services
Volume 38 : Issue 05
IN BRIEF
The weather during May was dominated by easterly wind
flow and transient toughs of low pressure systems. As a
result, the windward facing coasts of the larger islands experienced Trade showers on most of the days, while the
leeward side experienced mainly fine weather.
in the Western Division, with Nadi to Tavua corridor recording below average rainfall. Moreover, Nadi Airport, Momi,
Lautoka Mill and Tavua recorded 5 or less rain days.
Overall, rainfall during the month varied across the country
with 6 out of 23 stations registering below average, 8 averAn active Madden Julian Oscillation contributed to the for- age and 9 above average.
mation of two off season tropical cyclones in the Southwest
Pacific during May 2017. Tropical cyclone Donna reached The maximum air temperatures were generally above normaximum intensity of Category 4 system, making it the mal during the month, with 18 out of the 20 stations recordstrongest May tropical cyclone on record in the Southern ing anomalies ≥0.5°C and 2 within ±0.5°C.
Hemisphere. It passed through Solomon Islands, Vanuatu
and New Caledonia. Tropical cyclone Ella traversed to the The minimum air temperatures were above normal across
far north of Fiji Waters without any significant direct effect the country, with all 20 stations registering anomalies ≥0.5°
on the land areas. Tropical cyclone Ella reached maximum C.
intensity of a Category 2 system.
The daily daytime temperature as high as 34.7°C was recth
A trough together with a shallow low pressure system re- orded at Yaqara thon the 13 , followed by Nacocolevu with
sulted in significant rainfall across the country on the 21st 34.5°C on the 11 .
and 22nd. Heavy rain was experienced especially over the
as low as 11.8°C was
eastern half of Viti Levu with RKS, Laucala Bay, Koronivia The daily night-time air temperatures
th
recorded
at
Nadarivatu
on
the
29
,
followed
by Monasavu
and Dobuilevu recording 199.0mm, 176.5mm, 151.0mm
th
and 150.5mm of rainfall over the 48-hour period. Conse- with 15.4°C on the 29 .
quently, parts of the Central Division were flooded. There A total of eleven new temperature records for May were
were also reports of flooding in the Northern Division.
established during the month (Table 1).
st
nd
Apart from the rainfall on the 21 to 22 , it was mostly dry
2.
WEATHER PATTERNS
The weather in May was mostly influenced by trough of
low pressure systems and the easterly Trade winds.
A trough of low pressure affected Fiji until the 3rd which
brought occasional showers over the country. Following
the trough, a strong southeast wind flow covered the group
till the 4th. From the 5th, another trough moved over the
country from the north and caused occasional showers until
the 7th. On the 8th, a ridge of high pressure extended onto
the group from the south and displaced the trough back
northwards keeping the strong Trade easterlies over Fiji
until the 10th. This prevailing condition brought Trade
showers mainly over the eastern parts and interior of the
main islands while the northern and eastern parts of Fiji
experienced occasional showers.
The second off-season tropical cyclone “Ella” was named
on the 9th and it indirectly affected the northern parts of Fiji
between 11th to 14th. Although TC Ella did not directly
affect Fiji, associated strong winds and rain bands affected
the northern parts of the group from time to time. TC Ella
moved north of Fiji and passed very close to Rotuma on
the 14th. Rotuma was affected by the strong winds on the
*Previously known as the Fiji Islands Weather Summary
14th.
A high pressure system to the far south of Fiji directed a
strong moist east to southeast wind flow over the group
until the 19th. However, on the 20th, a trough to the north of
Fiji drifted southwards over the group and affected the
whole country on the 21st. This coupled with a shallow low
pressure system just to the northwest of Viti Levu brought
continuous heavy rain which resulted in flooding in some
parts of the country over this period. The rain eased over
the group on the 23rd as the trough moved eastwards.
Following the passage of the trough, a high pressure system to the far south of Fiji directed strong east to southeast
Trade wind flow over the group from the 24th till the 31st,
allowing generally fine conditions over Fiji till month end
despite a weak trough lingering around the eastern part of
the country on the last day of the month.
Rotuma’s weather was mainly affected by a series of
troughs and the easterly Trade winds during the month.
1
Fiji Climate Summary - May 2017
3.
Volume 38 : Issue 05
RAINFALL
Rainfall during May varied and ranged from below average
to above average across the country (Table 2 & Figures 15). Six out of twenty three sites recorded below average
rainfall, eight sites recorded average rainfall and nine sites
recorded above average rainfall.
An active trough of low pressure resulted in significant
rainfall across the country on the 21st and 22nd. Heavy rainfall especially over the eastern half of Viti Levu resulted
rainfall in excess of 100mm over 24 hours at a number of
stations. RKS, Koronivia, Laucala Bay, Monasavu and
Nasinu registered 138.5mm, 116.0mm, 107.8mm,
101.2mm and 100.5mm of rainfall on the 22nd, respectively. Moreover, RKS, Laucala Bay, Koronivia and Dobuilevu recorded 199.0mm, 176.5mm, 151.0mm and 150.5mm
of rainfall over the 48-hour period from the 21st to the 22nd.
Consequently, parts of the Central Division were flooded.
There were also reports of isolated flooding in the Northern
Division.
338.0mm, Koronivia with 312.2mm and Laucala Bay with
285.2mm.
The driest station was Rarawai Mill with 46.4mm, followed by Nadi Airport with 55.2mm, Yaqara with 55.5mm
and Lautoka Mill with 65.8mm.
The number of rain days (rainfall ≥0.1mm) during the
month ranged from 3 to 30 days. Monasavu recorded the
greatest number of rain days with rainfall recorded on every day of the month, except for 28th. This was followed by
29 days at Koronivia, 26 days at RKS and 25 days at Laucala Bay.
On the other hand, Nadi, Momi, Lautoka Mill and Tavua
registered only 5 or less rain days.
No new rainfall record was established during May 2017.
Apart from the heavy rainfall on the 22nd, another notable
24-hour total rainfall was recorded at Lakeba with
103.4mm of rainfall on the 6th.
Monasavu was the wettest location during the month with a
total monthly rainfall of 534.1mm, followed by RKS with
Figure 1
Normal: Long term average from 1971 to 2000
Well Below Average: Rainfall less than 40% of normal
Below Average: Rainfall between 40 to 79%
Rain Day: Rainfall ≥ 0.1mm
Average: Rainfall between 80 to 119%
Above Average: Rainfall between 120 to 199%
Well Above Average: Rainfall greater than or equal to 200% of normal
2
Fiji Climate Summary - May 2017
4.
Volume 38 : Issue 05
AIR TEMPERATURES
A.
Maximum Daytime Air Temperatures
Generally above normal daytime temperatures were recorded during the month, with 18 out of the 20 stations recording anomalies ≥0.5°C and two within ±0.5°C (Table 2
& Figures 2-5).
The warmest days on average was experienced at Rarawai
Mill with 32.1oC, followed by Nacocolevu with 32.0oC and
Yaqara with 31.9°C. On the other hand, Monasavu recorded the coolest maximum temperature on average of 23.3°
C, followed by Nadarivatu with 24.4°C.
Daily daytime temperature as high as 34.7°C was recorded
at Yaqara on the 13th, followed by Nacocolevu with 34.5°C
on the 11th, and Keiyasi & Rarawai Mill both with 34.0°C
on 11th and 17th, respectively. On the other hand, the lowest
daytime temperature was recorded at Monasavu with
20.3°C on the 22nd, followed by 21.1°C at Nadarivatu on
the 22nd.
The greatest mean monthly maximum temperature anomaly from the normal of +3.1°C was observed at Nacocolevu,
followed by +1.8°C at Viwa, +1.6°C at Lautoka Mill and
+1.5°C at Rarawai Mill, Penang Mill and Vunisea.
A new high daily maximum temperature record and a number of mean daily maximum temperature records for May
were established during the month (Table 1).
B.
Minimum Night-time Air Temperatures
The minimum air temperatures were above normal across
the country, with all 20 stations registering anomalies ≥0.5°
C (Table 2 & Figures 2-5).
The coolest night on average was experienced at Nadarivatu with 17.9°C, followed by Monasavu with 18.6°C, Rarawai Mill with 20.0°C and Keiyasi with 20.2°C. In contrast, Rotuma registered warmest nights on average with
25.8°C, followed by 24.6°C at Viwa, 24.5°C at Savusavu
Airfield and 24.4°C at Udu Point and Matei Airfield.
The lowest daily night-time temperature was registered at
Nadarivatu with 11.8°C on the 29th, followed by Monasavu
with 15.4°C on the 29th and 15.5°C at Navua and Rarawai
Mill on the 26th and 29th, respectively. On the other hand,
the warmest night was at Rotuma with 27.7oC on the 29th,
followed by Savusavu Airfield with 26.9oC on the 5th, and
Yaqara and Matei Airfield with both 26.4oC on the 11th and
15th, respectively.
The greatest positive mean monthly night-time air temperature anomaly from the normal of +2.9°C was recorded at
Tokotoko (Navua), followed by +2.2°C at Savusavu Airfield and +1.4°C at Nadi Airport.
A number of new high daily minimum temperature records
and new mean daily minimum temperature records for May
were established during the month (Table 1).
TABLE 1. CLIMATE RECORDS ESTABLISHED IN MAY 2017
Element
Station
Observed
(record)
Daily Maximum Temperature
Tokotoko
32.0oC
Daily Minimum Temperature
Tokotoko
Daily Minimum Temperature
On
Rank
Previous
(record)
Year
Records
Began
28th New High
31.7oC
1993
1992
25.0oC
5th
New High
24.8oC
2004
1992
Rotuma
27.7oC
29th New High
27.5oC
1997
1933
Mean Monthly Maximum Temperature
Nacocolevu
32.0oC
-
New High
30.1oC
2001
1938
Mean Monthly Maximum Temperature
Lautoka Mill
31.1oC
-
New High
31.0oC
2010
1930
Mean Monthly Maximum Temperature
Vunisea
28.8oC
-
New High
28.4oC
1958
1947
Mean Monthly Minimum Temperature
Laucala Bay
23.7oC
-
New High
23.6oC
2002
1942
Mean Monthly Minimum Temperature
Rotuma
25.8oC
-
New High
25.5oC
1998
1933
Mean Monthly Minimum Temperature
Savusavu Airfield
24.5oC
-
New High
24.4oC
2002
1956
Mean Monthly Minimum Temperature
Nausori Airport
22.9oC
-
New High
22.8oC
1975
1956
Mean Monthly Minimum Temperature
Matei Airfield
24.4oC
-
New High
24.2oC
1968
1956
Note: All comparisons in this summary are with respect to “Climatic Normals”. This is defined to be the average climate condition over a 30-year period. Fiji uses 1971-2000 period as its “climatic normal” period, unless otherwise stated.
3
Fiji Climate Summary - May 2017
Volume 38 : Issue 05
TABLE 2. DAILY CLIMATE REPORTING SITES: SUMMARY FOR MAY 2017
NADI AIRPORT
SUVA/LAUCALA BAY
NACOCOLEVU
ROTUMA
VIWA
UDU POINT
SAVUSAVU AIRFIELD
LABASA AIRFIELD
KORONIVIA
NAUSORI AIRPORT
NAVUA/TOKOTOKO
MONASAVU
LAUTOKA AES
BA/RARAWAI MILL
PENANG MILL
MATEI AIRFIELD
LAKEBA
VUNISEA
MATUKU
ONO-I-LAU
SEAQAQA
YASAWA-I-RARA
DOBUILEVU
RAINFALL
TOTAL RAIN MAX.
* DAYS FALL
MM
% +
MM ON
55 62 4
45 22
285 106 25 108 22
106 124 9
41 22
216 73 21
46 15
137 122 11
94 22
170 101 19
34 18
114 58 13
40 22
151 131 10
61 22
312 126 29 116 22
249 100 23
77 22
263 92 22
59 22
534 179 30 101 22
66 79 5
63 22
46 49 6
43 22
163 101 15
76 22
213 92 20
72 6
183 137 17 103 6
246 132 18
95 22
117 76 16
39 23
142 138 13 103 22
136 106 11
91 22
77 88
6
62 22
193 148 20
91 22
AIR TEMPERATURES
AVERAGE DAILY
EXTREME
MAX. #
MIN. #
MAX.
MIN.
C
C
C
C
C ON
C
30.6 0.9 22.3 2.1 32.9 5 17.0
29.1 0.6 23.7 1.5 31.1 12 19.6
32.0 3.1 21.1 1.4 34.5 11 17.5
31.1 1.1 25.8 1.2 32.7 3 24.7
31.0 1.8 24.6 0.6 33.0 14 22.3
28.9 -0.3 24.4 0.9 29.9 4 21.5
28.8 0.3 24.5 2.2 30.0 16 20.7
31.2 1.0 21.0 1.1 32.6 13 17.0
29.2 1.1 22.7 1.7 31.5 13 18.8
29.1 1.2 22.9 1.7 31.1 13 18.5
29.4 0.8 22.6 2.9 32.0 28 15.5
23.3 0.7 18.6 1.6 26.5 13 15.4
31.1 1.6 22.3 0.8 33.5 14 20.0
32.1 1.5 20.0 0.9 34.0 17 15.5
30.0 1.5 23.3 1.2 32.2 5 19.0
29.7 1.2 24.4 1.5 31.6 14 21.5
28.7 0.7 24.0 1.2 30.5 13 19.9
28.8 1.5 23.2 1.7 31.0 27 19.9
28.5 0.9 24.1 1.6 30.5 13 20.5
28.1 1.4 23.1 1.0 33.4 13 19.6
ON
29
26
25
16
30
2
26
28
29
29
26
29
29
29
27
2
28
26
29
23
SUNSHINE
TOTAL
*
HRS
%
199 95
132 90
172 107
TEMPERATURE( C)HUMIDITY WIND SUN RAD
DRY WET RH% VP
%OF MJ/
MEAN
(AVERAGE AT 9AM)
KT POS SQ.M
NADI AIRPORT
SUVA/LAUCALA BAY
NACOCOLEVU
ROTUMA
VIWA
UDU POINT
SAVUSAVU AIRFIELD
LABASA AIRFIELD
KORONIVIA
NAUSORI AIRPORT
NAVUA/TOKOTOKO
MONASAVU
LAUTOKA AES
BA/RARAWAI MILL
PENANG MILL
MATEI AIRFIELD
LAKEBA
VUNISEA
MATUKU
ONO-I-LAU
26.4
26.4
26.5
28.4
27.8
26.6
26.6
26.1
26.0
26.0
26.2
21.0
26.7
26.1
26.7
27.1
26.5
26.0
26.3
25.6
27.0
26.8
26.3
29.0
28.8
27.2
27.1
27.9
26.8
26.2
26.1
20.6
28.4
27.6
26.8
27.6
27.1
25.7
26.9
26.3
23.4
24.4
23.8
26.5
25.7
25.3
24.6
24.8
24.4
24.2
24.0
19.7
24.2
24.8
24.2
24.7
24.3
23.8
23.6
23.2
73
81
80
82
77
85
81
77
82
84
86
91
70
79
80
78
79
85
75
76
26.0
28.6
27.5
32.7
30.5
30.7
29.1
28.8
28.7
28.5
28.4
22.2
27.0
29.2
28.1
28.8
28.3
28.1
26.5
26.0
5.4
59 12.9
39 12.8$
53 14.5$
4.3
MEAN TEMPERATURE IS (MAX+MIN)/2;
WIND IS MEAN SPEED AT 06,12,18,24 HOURS.
$ :SOLAR RADIATION CALCULATED FROM SUNSHINE DURATION. # :DEPARTURE FROM LONG-TERM
AVERAGES (1971-2000).+ :NUMBER OF DAYS WITH 0.1 MM OR MORE RAIN. * :PERCENT OF LONGTERM AVERAGES. BLUE FONT– MISSING RECORDS OF LESS THAN OR EQUAL TO 5 DAYS.
4
Fiji Climate Summary - May 2017
Volume 38 : Issue 05
Figure 2
Figure 3
Figure 4
5
Fiji Climate Summary - May 2017
Volume 38 : Issue 05
Figure 5
6.
RELATIVE HUMIDITY AT 0900HOURS
The 9am average relative humidity (RH) ranged from 70%
to 91% during the month (Table 2). Generally normal RH
was observed across the country with RH anomalies ranging within ±5%. The only exception to this was Udu Point
where RH anomaly was +6%.
The monthly average RH in the Northern Division ranged
from 78% to 81%, with daily values from 55% to 99%.
Significant positive anomaly of +6% was recorded at Udu
Point, while the most significant negative anomaly of -4%
was recorded at Labasa Airport.
The monthly average RH in the Western Division ranged
between 70% and 91%, while the daily values ranged between 57% to 91%. The anomalies during the month
ranged from –5% to +2%. Negative anomaly of –5% was
recorded at Lautoka and Penang Mills, while positive
anomaly of +2% was recorded at Monasavu.
The Eastern Division mean monthly RH ranged from 75%
to 89%, while the daily values were between 63% to 97%.
The anomalies during the month ranged from 0% (Matuku)
to +5% (Vunisea).
The monthly average RH in the Central Division ranged
between 81% and 84%, while the daily values were between 60% to 99%. The RH anomalies ranged from –1%
(Koronivia) to +2% (Tokotoko).
7.
The mean monthly RH at Rotuma was 82%, with an anomaly of +2%.
SUNSHINE
Near normal sunshine was recorded at Nacocolevu, Nadi The total monthly bright sunshine at Nacocolevu was
Airport and Laucala Bay (Suva) with 107%, 95% and 90% 172.1 hours, with a daily mean of 5.7 hours. The station’s
of normal bright sunshine hours, respectively (Table 2).
highest daily bright sunshine of 10.0 hours was on the 4th,
followed by 9.2 hours on the 7th and 12th. On the other
Nadi Airport recorded 198.9 hours of the total bright sun- hand, overcast condition was experienced on 22nd with no
shine, with a mean of 6.4 hours/day. The station recorded bright sunshine and on the 14th with only 0.2 hours (12
more than 10 hours of bright sunshine on the 9th, 18th, 25th minutes) of bright sunshine.
and 29th. On the other hand, overcast conditions were experienced on the 1st and 22nd with less than an hour of bright NB: Rotuma’s sunshine analysis is not presented due to 3
sunshine recorded on 10th and 20th.
consecutive days of missing data.
Laucala Bay (Suva) recorded 131.9 hours of total monthly
bright sunshine, with a mean of 4.3 hours/day. The longest
duration of bright sunshine of 10.0hours was recorded on
26th. Cloudy and overcast conditions was experienced on
20th with less than one hour of bright sunshine recorded,
while no bright sunshine hours was recorded from 21st to
23rd.
6
Fiji Climate Summary - May 2017
8.
Volume 38 : Issue 05
WIND SUMMARY
The 10-minute average wind statistics recorded every three
hours at Nadi Airport during May showed that northeasterly winds were predominant, accounting for 44.4% of
the total observations, followed by northerly winds with
11.3% and easterly with 9.7% (Figure 6(a)). Calm conditions were recorded on 2.4% of the occasions. Generally,
10-minute average wind speeds were light to moderate in
strength (Figure 6a & 6b).
At Nausori Airport, calm conditions accounted for 37.5%
of the total three hourly observations. Easterly winds were
predominant with 31.5% of the observations, followed by
south easterly winds with 19.8%. The 10-minute average
wind speeds were light to gentle (Figure 7a & 7b).
The wind anomalies map on the NOAA website show persistence of variable winds of up to 2m/s in the Fiji region
(Figure 13).
Note:
light air: 1-3 knots, light breeze: 4–6 knots, gentle breeze: 7-10 knots,
moderate breeze: 11-16 knots, fresh breeze: 17-21 knots, strong breeze: 22
-27knots, near gale: 28-33 knots; gale: 34-40 knots; strong gale: 41-47
knots
Figure 6(a) Surface Wind Direction for Nadi Airport, Fiji. (WMO 91680 Figure 6(b) Surface Wind Speed for Nadi Airport, Fiji. (WMO 91680 Lat
Lat 17°45'35"South Long 177°26'42"East Height above MSL 22m)
17°45'35"South Long 177°26'42"East Height above MSL 22m)
Figure 7(a) Surface Wind Direction for Nausori Airport, Fiji. (WMO Figure 7(b) Surface Wind Speed for Nausori Airport, Fiji. (WMO 91683
91683 Lat 18°02'47"South Long 178°33'33"East Height above MSL 3m) Lat 18°02'47"South Long 178°33'33"East Height above MSL 3m)
7
Fiji Climate Summary - May 2017
9.
Volume 38 : Issue 05
EVAPORATION
Figure 8
Daily Evaporation for May 2017
Nadi
6.0
6.0
6.0
5.8
5.6 5.6
6.0
5.8
5.9
5.3
Evaporation (mm)
5.0 4.9
5.0
4.5
5.0
4.3 4.3
4.0
3.8
3.4
3.2
3.1
2.9
4.0 4.0
4.0 4.0
3.4
2.0
2.0 2.0
1.9
2.1 2.2
2.4
2.0
3
0.7
4
5
6
7
8
9
2.2
2.0
1.4
0.2
2
4.0
1.4
0.6
1
3.8
2.7
2.5
1.8
1.5
5.2
3.5
3.4
2.9
2.3
2.0
4.0
3.7 3.8
Suva
0.5
0.0
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Date
The total monthly raised pan evaporation at Nadi Airport was 119.8mm, while Laucala Bay recorded 89.5mm. Nadi Airport recorded the highest daily evaporation of 6.0mm on the 8th, 13th, 18th and 28th, with Laucala Bay registering the
highest of 5.8mm on the 18th & 28th.
10.
RADIATION
Radiation (MJ/m 2 )
May 2017 Daily Radiation at Nadi Airport
Figure 9:
The mean daily solar
radiation at Nadi
Airport during May
2017 was 12.7MJ/
m2, compared to
14.9MJ/m2 over 30
year average (19712000).
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
NB: Missing Radiation data on the 20th.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
Days in May
11.
SEA SURFACE TEMPERATURE (SST)
Figure 10:
SSTs were above
normal in the Fiji
region during May
2017 (base period:
1981-2010).
http://
www.esrl.noaa.gov/
psd/map/clim/
sst.shtml
8
Fiji Climate Summary - May 2017
12.
Volume 38 : Issue 05
CLOUD COVER
Figure 11:
OLR anomalies indicate presence of below normal cloud
cover in the Fiji region (Fiji: ~17ºS,
180º) (base period:
1981-2010).
http://
www.esrl.noaa.gov/
psd/map/clim/
olr.shtml
13.
SEA LEVEL
Figure 12:
Near normal sea level
persisted in the Fiji
Waters (base period:
1981-2010).
http://
www.cpc.ncep.noaa.g
ov/products/
analysis_monitoring/
ocean/
weeklyenso_clim_8110/wksl_anm.gif
14.
WIND ANOMALIES
Figure 13:
Reanalysis data show
variable wind direction of up to 2m/s in
the Fiji region during
May
2017
(Fiji:
~17ºS, 180º) (base
period: 1981-2010).
http://
www.esrl.noaa.gov/
psd/map/images/rnl/
sfcwnd_30a.rnl.gif
9