Seasonal Weather Forecast Talk Show on Capricorn FM and North West FM

abusivetrainerΔίκτυα και Επικοινωνίες

20 Νοε 2013 (πριν από 3 χρόνια και 4 μήνες)

180 εμφανίσεις

1





Season
al Weather Forecast Talk S
how on Capricorn

FM

and North
West FM


How
accurate

w
as

the
Seasonal Forecast

issued last month (October
)
?

Accuracy is an important
part

of forecasting
.

F
irstly
,

let me remind listeners about
last month’s
seasonal
rainfall
forecast
.

The seasonal
rainfall
forecast
shown
in
F
igure 1
indicated
high
p
robabilities for
below
-
normal
rainfall conditions over
Limpopo Province (LP)

and
continuing below
-
normal
conditions in
North West Province (NWP)

duri
ng the period

of
October
to

December
.

The forecast was correct for most days
in

the month of October. This
forecast highlighted one important aspect of weather forecast
ing

which is

the

continuous update
and evaluation of available forecasting products at different scale. For example
,

a weekly
forecast
,

in this case issued
i
n the last week of October
,

was more accurate than the seasonal
forecast issued
2

months earlier.


Figure
1
: Probab
ilistic above
-
normal

(left panel)

and below
-
normal

(right panel)

rainfall
forecast for three overlapping seasons valid for the period of

October

2013

to

February

2014



The maximum temperatures (day temperature
s
)
we
re forecast to
become

above
-
normal for
both LP and NWP

during

the period of October to
December
. The tendency of warmer
maximum temperatures
wa
s gradually expanded from the west of
N
WP during early spring
(Figure 2).
The minimum temperature (night temperature) forecast system indicat
ed

warmer
2


c
onditions than normal for most of LP and NWP
,
with the exception of the southwestern parts
of NWP
for which cooler conditions
we
re

expected
during
December 2013
to

February 2014

(Figure
2
)
. Above
-
normal minimum temperatures
we
re expected to continue during

the

October

to

December

2013
and
November 2013
to

January 2014

periods. These conditions
we
re expected
to worsen the current drought conditions experienced in NWP

if the expected November rain does
not come early
.


Figure
2
: Probabilistic maximum (left panel) and
minimum
(right panel) temperature
forecasts for the three overlapping seas
ons

valid for the period

October 2013

to

February
2014


Where can a farmer access the seasonal weather
forecast?

The
South African Weather Service
(SAWS) is
the authoritative supplier of
w
eather
f
orecasts and
information for South Africa
. There are also other institutions outside the borders of South Africa
issuing weather forecast
s
.
We also have universities

doing a lot

of research and improving the
models used for weather forecasting. Thirdly
,

we have private and public institutions developing
models to best f
orecast the weather.


Accessibility of seasonal weather fo
recast
s

is still a challenge in S
outh Africa, especially
for
subsistence
farmers
, and

lack of technology to access the information is a
key

factor.
One of the
ma
jor

challenges
is the understanding

of weather forecast

phenomen
a
.
The
project

on
seasonal
weather forecast dissemination
methods is relevant

because the ma
in

objective is to improve
weather information dissemination
methods
and the understanding thereof.




3


How
m
uch
r
ainfall was received in the month of

September 2013
?

Figure 3 indicates an

accumulation of 10
-
day rainfall su
rfaces created by a combination of ARC
-
ISCW and
SAWS

automatic weather station data with satellite rainfall estimates from NOAA CPC
(National Oceanic
and Atmospheric Administration

Climate Prediction Center) available through
FEWSNET (Famine
E
arly Warning
Systems Network).

During the month of

September

2013
most
parts of
LP and

NWP received 0
-
5mm of rainfall and the north eastern parts of LP

over
soutpansber
g received between 25 and 75mm.


Figure 3
:

Total rainfall for

September

2013




What

is the seasonal outlook for the coming season (August to October
)?

Figure 4 indicate the p
robabilities for
above
-
normal rainfall conditions over LP and NWP
duri
ng the period from

November 2013

to

January 2014
.

The forecasting system indicate
s

greater
probabilities for below
-
normal rainfall conditions over NWP during

January

to

March

2014
.




4


Figure
4
: Probabilistic above
-
normal

(left panel)

and below
-
normal

(right panel)

rainfall
forecast for three overlapping seasons valid for the period of
Nov
ember

2013

to
March

2014




Table 1
:

Climatic rainfall and temperature for Potchefstroom station
,

North West
P
rovince





JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
Max Tem
26.60
27.12
25.60
22.80
21.15
18.61
18.36
22.31
25.33
26.67
26.86
26.86
Min Temp
15.79
15.11
13.45
9.90
6.20
3.27
2.01
5.41
8.81
12.26
13.69
14.99
Rainfall
142.24
72.25
87.91
47.92
14.53
13.42
0.81
7.68
14.23
50.30
79.91
105.37
JFM
FMA
MAM
AMJ
MJJ
JJA
JAS
ASO
SON
OND
NDJ
DJF
Max Tem
26.44
25.17
23.18
20.85
19.37
19.76
22.00
24.77
26.29
26.80
26.77
26.86
Min Temp
14.78
12.82
9.85
6.46
3.83
3.56
5.41
8.83
11.59
13.65
14.82
15.30
Rainfall
100.80
69.36
50.12
25.29
9.59
7.30
7.57
24.07
48.15
78.53
109.17
106.62
Potchefstroom
5


Table 2
:

Climatic rainfall and temperature for

Malamulela weather

station

of the ARC
,

Limpopo
P
rovince



Table 3
:

Climatic rainfall and temperature for
Lephalale

station
,

Limpopo
P
rovince



The maximum
temperatures (day temperature
s
)
are forecast to
become

above
-
normal for both
LP and NWP

during

November

2013 to January 2014
. The tendency of warmer maximum
temperatures is gradually expanded from the west of
N
WP during spring

(Figure 5)
.
The minimum
temperature (night temperature) forecast system is indicating
warmer conditions than normal
for most of LP and NWP
,
with the exce
ption of the southwestern parts
of NWP
for which cooler
conditions
are

expected
during
November
to

December

(Figure 5)
. Above
-
normal minimum
temperature
s

are expected to continue during
the
November to December
p
eriod. These
conditions are expected to

wors
en

the current drought
conditions expe
rienced in NWP

during late
spring and
the e
arly summer months
.




Item
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEPT
OCT
NOV
DEC
MaxTemp
31.36
32.64
32.31
28.93
28.26
26.56
25.18
27.90
30.66
31.98
31.84
32.37
Min Temp
20.53
19.98
18.72
15.33
11.86
8.93
8.47
9.81
14.06
17.76
18.80
20.35
Rainfall
242.59
73.58
32.03
58.17
19.06
4.70
10.18
2.76
18.27
20.88
75.25
128.28
Item
JFM
FMA
MAM
AMJ
MJJ
JJA
JAS
ASO
SON
OND
NDJ
DJF
MaxTemp
32.10
31.29
29.83
27.92
26.67
26.55
27.91
30.18
31.49
32.06
31.86
32.12
Min Temp
19.74
18.01
15.30
12.04
9.75
9.07
10.78
13.88
16.87
18.97
19.89
20.29
Rainfall
116.07
54.59
36.42
27.31
11.31
5.88
10.40
13.97
38.13
74.80
148.71
148.15
Malamulela
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEPT
OCT
NOV
DEC
MaxTemp
31.98
32.58
31.26
28.48
26.70
24.45
23.95
26.68
30.43
31.79
31.40
31.78
Min Temp
20.60
20.04
18.60
14.07
9.12
6.07
5.04
8.70
13.69
17.84
18.86
19.86
Rainfall
144.50
214.96
37.12
35.90
7.56
13.22
7.01
9.96
14.90
64.05
71.89
63.23
JFM
FMA
MAM
AMJ
MJJ
JJA
JAS
ASO
SON
OND
NDJ
DJF
MaxTemp
31.94
30.77
28.81
26.54
25.03
25.03
27.02
29.63
31.21
31.66
31.72
32.11
Min Temp
19.75
17.57
13.93
9.75
6.74
6.60
9.14
13.41
16.80
18.85
19.77
20.17
Rainfall
132.19
95.99
26.86
18.89
9.26
10.06
10.62
29.64
50.28
66.39
93.21
140.90
Lephalale
6


Figure
5
: Probabilistic maximum (left panel) and
minimum
(right panel) temperature
forecasts for the three overlapping seas
ons valid for the period of
Nov
ember

2013

to
M
ar
ch

2014







7


Maize
p
roduction
requirements in
Limpopo and North West
P
rovince


Table
4
:

W
ater and temperature impacts on maize production



Water and temperature play a major role in ma
i
ze production. The minimum water requirements
for maize production under
dryland

range from 250
-
300mm of rainfall and under irrigation the
range is from 8.5
-
12mm

pe
r day during pollination stage.


Why is this explanation and
S
easonal
W
eather
F
o
recasts of c
ritical importance?

Climate largely determines the success or failure of food production.

More than 70% of food and
nutrition insecure people are rural and therefore directly or indirectly dependent on agriculture
for

their livelihood. Seasonal weather forecasts as a planning tool can largely change food and
nutrition insecurity to food and nutrition security.


Growth originating in agriculture is almost three times more effective in reducing poverty than
growth in any

other sector of the economy. This was reiterated during a 2013
I
nternational Food
Security Futures Conference. You are the farmers; you have the responsibility not only of food
production but of food security, poverty reduction and economic growth in Sout
h Africa.


The rural population is expected to peak between 2020 and 2050 which could mean intensified
and exponential rural poverty and food and nutrition insecurity. Only you, our food producing
farmers, ca
n prevent a future catastrophe!


Farmers would b
e wise to base their agricultural production planning on scientifically
-
based
seasonal weather forecasts
.


Disclaimer

The ARC
-
ISCW and its collaborators have obtained data from sources believed to be reliable and
have made every reasonable effort to ensure

accuracy of the data. The ARC
-
ISCW and its
collaborators cannot assume responsibility for errors and omissions in the data nor in the
documentation accompanying them. The ARC
-
ISCW and its collaborators will not be held
responsible for any consequence from

the use or misuse of the data by any organisation or
individual.


For further informatio
n please contact the following:

Obed Phahlane


012 310 2520


PhahlaneO@arc.agric.za

Pabalelo Radingoana


012 310 25
85


RadingoanaM@arc.agric.za

Mahlatse Phuthi


012 319 6668


MahlatseP@daff.gov.za

Kentse Setshedi


012 319 2967


KentseS@daff.
gov.za

Adri Laas



012 310 2518


ISCWinfo@arc.agric.za


Minimum
Range
Precipitation
Extreme
Extreme
Vegetative
Stage
Pollination
Soft and
Hard
Dough
Vegetative
Stage
Pollination
Soft and
Hard
Dough
Germination
All
Growth
Stages
Germination
All
Growth
Stages
Germination
Stage
Vegetative
Stage
Pollination
2-3% Crop
Damage
per
Wilting
Day
7-10% Crop
Damage
per Wilting
Day
4.5% Crop
Damage
per Wilting
Day
4mm per
day
8.5-12mm
5.7 mm
Below 10°C
26°C
13°C
30°C
Summer
Summer
Summer
Critical Growing Stage Water
requirements
Requirements During
Requirements During
Long Days
250-300mm
5-19°C
30-48°C
Maize
Water Requirements
Dry Land
Irrigation
Minimum Summer
Temperatures
Maximum Summer
Temperatures
Critical Growing Stage Crop
Damage During Drought
Day Length
Temperature Requirements (
°C)
Short Days
Drying of Kernels
Winter
Winter
Soft and Hard Dough
CLIMATIC IMPACTS