XVII Climate Forum of Central America
(I FCAC - 2006)
Belize City, Belize, April 18 - 21, 2006
At the kind invitation of the National Meteorological and Hydrological Service of Belize, Ministry
of Natural Resources and the Environment, and with the support of the Republic of China
(Taiwan), the XVIII Climate Forum of Central America (I FCAC- 06) was held in Belize City,
Belize, during the period April 18 – 21, 2006.
The Climate Forum of Central America reviewed and analyzed the most recent oceanic and
atmospheric conditions, the global model forecasts and their implications on the rainfall and
temperature patterns in Central America, as well as the nationwide analyses contributed by
each Weather Service in the region, and by consensus, elaborated the foregoing Climate
Outlook for the May – June – July 2006 period across Central America.
Thus, the FCCA considering:
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The evolution of anomalies (deviation from the normal) in sea surface temperature
(SST) in the Tropical Atlantic and Pacific Oceans;
The trend in sea surface temperature for these oceans over the forthcoming months;
The predictions of several general atmospheric circulation models;
The historical rainfall records for years analogous to 2006 (see Annex);
The rainfall and air surface temperature scenarios, using contingency table analyses for
May, June and July 2006, based on the sea surface temperature values in the Northern
Tropical Atlantic and the El Niño 3 (CIGEFI-School of Physics/UCR); and
Rainfall probability estimates based on contingency analyses
The Atlantic Basin Hurricane Season 2006 forecasts
Recalling:
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That most global models agree on the persistence of near normal (neutral condition)
sea surface temperatures conditions in the Tropical Pacific Ocean for the next three
months;
That the above-normal surface temperatures will continue in the northern Tropical
Atlantic Ocean ;
The forecast of an above average hurricane activity during the 2006 hurricane Season
for the North Atlantic Basin, cognizant of the fact that at least one hurricane moved
through the western Caribbean during the trimester May- June- July of one of the
analogous years to 2006.
That some of the models are predicting positive surface pressure anomalies over the
extreme NW Caribbean, Yucatan, the eastern Gulf of Mexico, and the western Atlantic
during May, June and July 2006, which would favour a reduction in rainfall over some
areas of northern Central America.
The Forum estimated the probability that cumulative rainfall from May through July 2006 be
above normal (AN), within normal (N) or below normal (BN) range of the historical records.
Areas of Central America with a similar probability that rains will fit within each of these
categories are indicated by colours on the attached map. The following table indicates the
probability for each zone:
% Probability
Category
#
(A) Above Normal
#
N) Within Normal
#
(B ) Below Normal
Green Areas
Greater probability that cumulative rainfall during May, June and July 2006 will be above normal
(AN). These include:
The Boca Costa and Pacific coast of Guatemala, eastern and western coast of El Salvador, the
Pacific coastal areas of southwestern, central and southern Honduras, the Pacific coast of
Nicaragua and the northern and central Pacific coast of Costa Rica .
Gray Areas
Greater probability that cumulative rainfall for May, June and July 2006 will be within the normal
to above normal range or wet (N-AN). These include:
Central and southern regions of Belize including adjacent coastal waters, the central highlands,
the northern zone of El Peten and Caribbean coast of Guatemala, Western zone of Honduras,
and the central region of El Salvador.
Yellow Areas
Greater probability that cumulative rainfall from May-June -July 2006 will be from normal to
below normal or dry (N-BN). These include:
The northern region of Belize; east central Guatemala; northern inland region, eastern zone and
the Caribbean coast of Honduras; northern, central and Caribbean region so Nicaragua;
northern, central and southern Pacific coast of Costa Rica; and the entire Pacific Coast of
Panama.
Maroon Areas
Greater Probability that cumulative Rainfall during May-June-July 2006 will be within the below
normal range or dry (BN). These include:
The Caribbean coast and coastal plains of Costa Rica and Panama.
Perspective by Country
Belize
The Rainfall Outlook for May, June and July 2006 indicate that areas of the Corozal, Orange
Walk and Belize districts will have cumulative rainfall within the normal range (N) with a
tendency toward the below normal (BN) range. Across the remainder of the country and coastal
waters, cumulative rainfall will be above normal (AB).
The Wet Season is expected to start normally this year, in early June, and the August Maga
Season or mid summer drought is expected during the second ten-days of August and will be of
moderate intensity.
Honduras
Much wetter conditions than normal are expected over southern and central regions during
June, with a normal onset of the Rainy Season. The mid summer drought in these areas will not
be very pronounced.
Over western regions a late start of the rainy is expected and above normal rainfall is
anticipated during the month of July.
While, in the northern region the Rainy Season is expected to be earlier than normal. The first
two week of June will have rainfall above normal, with below normal rainfall expected during the
second two weeks.
Guatemala:
The onset of the Rainy Season is expected around April 20 through May 5 in the southwestern
region, around May 20 through June 5 over the greater part of the central highland, from May 10
through May 25 along the Pacific coast and between May 25 through June 10 in the eastern
areas and during the period June 10 – 25 over northern department of El Peten.
Although there is a greater probability that rainfall will be in the normal range over eastern
Guatemala, it is expected that the rainfall during May and June will tend to be below normal
(BN) and above normal (AN) for the months of July and August.
The month of May will be the driest month over northern areas of the country, which will be
favourable for the outbreak of forest fires.
The region with greater probability of above normal (AB) is the southwestern area of the
country, while greater probability of normal to below normal (N-BN) cumulative rainfall is for
eastern territories
El Salvador:
Influenced by the relatively warm sea surface waters of the Tropical North Atlantic (TNA) and a
weak cool phase (La Niña) of ENSO in the Pacific, an early start of the rains is expected during
April 26 – 30 in the western region, especially in the elevated mountainous areas; while over the
remainder of the country, the onset of the rains will be during the first ten-days of May.
Cumulative rainfall for May will be above normal (AN), it will be normal (N) in June and
predominantly normal (N) in June, with a tendency of above normal (AB), especially along the
coastal zone, ending with above normal rainfall cumulative by the end of the first three months
of the rainy season.
Rainfall will also be predominantly in the normal range during August, and the dry spells or mid
summer drought during July and August won’t be extended or prolonged. During May and
August, it is expected that one or two “atemporaladas” or squally weather will develop, one in
early June and the other around the end of June.
Nicaragua
It is expected that the rainy season will become established during the third ten-day of May
around the country, and it is very probable that showers will remain generally isolated of
moderate intensity during the first two decades of May.
Along the Pacific coast it is expected that cumulative rainfall will be above normal (AN), while
over the rest of the country the scenario is for a greater probability of normal rainfall, having the
following characteristics:
Along the western Pacific, cumulative rainfall will range between 355 to 847 mm. In the Central
Pacific, it is probable that cumulative rainfall will be between 340 to 640 mm. Along the southern
Pacific zone cumulative rainfall will range between 420 and 680 mm. In the northern zone it is
very probable that cumulative rainfall will amount to 330 mm to 660 mm. Over central areas,
cumulative rainfall during the next three months will vary from 290 to 890 mm. Along the
Caribbean sector the most probable scenario will be rainfall ranging from 725 mm to 1430 mm.
Over the Pacific region and western zones of northern and central Nicaragua, it is expected that
the Mid Summer drought will be moderate or less intense.
It is important that within the Analogous years considered in the analysis of the Climate Outlook,
is the year 1996, the year when the country was affected by Hurricane Cesar; consequently, it is
possible that the region could be impacted by a similar system during the first three months of
the 2006 Hurricane Season.
Costa Rica:
The onset of the rainy season will occur during the first week of April in the southern Pacific
coast and along the north Pacific coast by the third week of May. In general these dates
represent about 5 to 10 days ahead of the normal start of the rains.
Only along the Pacific coast is the rainfall expected to be very variable, that is all three
scenarios could develop. According to the analysis, it is likely that April and May will have
rainfall deficits and June may be very wet. Over the rest of the Pacific region and the Central
Valley, rainfall conditions will vary From normal to wet conditions, with June and August will be
wet months In the North and the Caribbean region, especially along the coastal zone, rainfall
deficit is expected from June through August, only in May will there be normal to above normal
rainfall. This indicates a greater probability of lower frequency of temporales.
With respect to the “Veranillos” or Mid-summer droughts around mid year, the models are not
favouring a moderate or intense event. However, even though no intense or extended dry spell
is expected there will be a drop in rainfall for the Pacific north and the Central Valley. In
connection with the Hurricane Season, conditions in August will be wetter along all the coast of
the Pacific, with the possibility of a “temporal”
Panama:
Along the Caribbean coast of Panama, the cumulative rainfall is expected to be below normal
(BN) during May, June and July, 2006.
Along the Pacific coast cumulative rainfall will be within the normal range
The onset of the Rainy Season:
An analysis of the analogous years to 2006, the rainy season will commence around APRIL 26,
at Tonosí, Divisa, and Anton it will be around May 11, for Los Santos the rains will begin around
May 16, for the City of Panama and the Canal Watershed it will be after May 6, with the chance
of onset within one week of the indicated dates.
NOTES:
1. The Climate Forum of Central America (FCAC) is a working group coordinated by the Comité
Regional de Recursos Hidráulicos del Istmo Centroamericano (CRRH/SICA) (Regional Water
Resource Committee of the Central American Isthmus) that brings together experts in
meteorology, climatology and hydrology from the Meteorological Services, universities, and
private enterprise in Central America and Mexico
2. Additional information on the Climate Outlook, by country, can be found at the following sites:
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www.aguayclima.com/clima/foroclimatico
www.insivumeh.gob.gt
www.cengicana.org
www.hydromet.gov.bz
www.snet.gob.sv
www.flexpma.com
www.imn.ac.cr
www.etesa.com.pa
www.hidromet.com.pa
www.ineter.gob.ni