WEATHER SUMMARY 2011

Belize, Central America

National Meteorological Service, Belize

January 30, 2012

By

Catherine Cumberbatch

In January, a total of four cold fronts reached Belize. These frontal boundaries didn’t accompany any significant rainfall. Rainfall was below normal and no minimum temperatures were broken.

In February usually marks the start of the dry season, however two cold fronts, a surface trough and moist north-easterly airflow gave way to an increase in showers that resulted in rainfall at most stations to be above normal. The temperatures remain within the normal range during the month. The last few days ended with generally fair and dry weather as south-easterly airflow became the dominant feature affecting our weather.

In March, April and May for 2011, the most significant weather element that affected was rainfall. Table 1 below shows monthly rainfall in millimetre for March, April, May and June compare with their averages across the country.

Assessment of the monthly average rainfall for the country showed most rainfall station in March, April and May. They received rainfall below the normal especially in the months of April and May.

In March, a cold front that crossed the country caused certain parts of the country to received significant amounts of rainfall way above the normal, whiles the other station received near normal rainfall.

In April, only Central Farm and Chaa Creek, both received six (6%) percent above the normal. Gales point, La Democracia, Libertad and Rio Bravo received zero (0%) percent of the normal. Melinda and Philip Goldson International Airport received less than five (5%) percent of the normal. Savannah, Spanish Lookout and Tower Hill got less than thirty (30%) percent of the normal. All other stations got more than forty (40%) percent of the normal.

In May, Baldy Beacon, Rio Bravo, Hershey, Belize Zoo, Tower Hill and Libertad received under (5%) of the normal. Gales Point and Philip Goldson Int’l Airport got 5.7 and 8.9% respectively of the normal. Barton Creek, Big Falls Plantation, La Democracia, Savannah, and Spanish Lookout got under 20% of the normal. All other station received between 20-25% of the normal, except Melinda and Pomona who got 36.7 and 50.5% of the normal. All stations in the month of May got below normal rainfall.

In the Month of June, most rainfall stations got rainfall above their averages.

This summary also seeks to find out if the below normal rainfall result in a meteorological drought.

Meteorological Drought can be defined as an extended period of abnormally dry that resulted in less precipitation than the average.

Meteorological drought is determined by comparing the average rainfall over a period of two consecutive months with the average normal for a similar bi monthly period for each station. Table is calculated as follows:

Values=( ( Month1 +Month 2)/ (Normal month 1 + Normal Month 2 )X 100

The percent value that is generated is used to quantify the thresholds of the drought index that is presented in the Table 2 below.

This index is similar to that used by the Australian Meteorological Service.

Table 2 Meteorological Drought Index

Summary of the drought Conditions for the months of April to June 2011.

Drought Indies across Belize showed that for the months of March/April, Belize Zoo, Gales Point and Libertad experienced severe drought. La Democracia, Philip Goldson International Airport and Punta Gouda got normal drought. The rest of the country experienced no drought.

For the months April/May 2011, except for Central Farm, Pomona and Punta Gorda which got Normal Drought, the rest of the country experienced Severe to Extreme drought.

For the months May/June 201, only Gales Point experience severe drought, whiles Chaa Creek got normal drought.

The rainy season normally starts around the middle of May in southern Belize and June in the north and ends in November. This year in the month of May, the entire country received rainfall below the normal. However in June a lingering surface trough, two tropical waves and the nearness of Tropical Storm Arlene produce significant amounts of rainfall over Belize. That resulted in most stations receiving rainfall amounts above their normal as indicated in the Table 1.

The first 3 months of the rainy season June, July and August (JJA) indicated that all stations received above normal rainfall. In July persistence TUTT and a tropical Wave gave way to considerable amount of rainfall over the country. In August a Mid-Upper Level Trough, two tropical waves and Tropical Storm Harvey on the 20^th August causes rainfall to be above normal.

In the latter half of the season, September, October and November (SON), several synoptic feature such as tropical waves, low surface pressure, upper levels troughs, Cold Fronts, the nearness of a Tropical Depression and Tropical Storms gave way to rainy spells across the country, that resulted in most stations in the month of September and October to received rainfall well above their normal. In the month of November most stations across the country rainfall was slightly below the normal.

In December, the passage of two cold fronts cause cool temperatures to prevail over the country that resulted in temperatures dropping to the upper 50’s along the coast to lower 50’s over inland areas and upper 40’s in the higher elevations. No temperatures were broken. Rainfall was slightly normal over some areas of the country.

The 2011, Hurricane season was projected to be more active than normal, with 12 to 18 named storms and 6 to 10 becoming Hurricanes. This year saw the development of 19 name storms and 7 hurricanes. Three of these became major hurricanes achieving category three strength or higher, (Irene 3, Katia and Ophelia 4). The Western Caribbean (Belize) saw the development of two systems that cause the country to go into emergency. These systems were Tropical Storm Harvey and Hurricane Rina. In the middle of August a westward moving tropical wave entered the Caribbean Sea. On August 18, the wave eventually gained enough organization to be classified as Tropical Depression Eight. It was upgraded to Tropical Storm Harvey on August 19. By late August 19, the storm was intensifying and it was announced that it could become a hurricane just before landfall on southern Belize. However, by Saturday afternoon, August 20, Harvey made landfall on southern Belize, never reaching hurricane strength. Minimal damage was estimated with no death. In the middle of October, the tail end of an early cold front moved into the western Caribbean. This cold front along with an east-south-easterly trade wind produced a broad area of cyclonic circulation over the south western Caribbean. On the 23^rd October, the area of low pressure became Tropical Depression 18. Hours later the depression became Tropical Storm Rina. The storm continued to intensify and on the 24^th it became Hurricane Rina. Rina, a category 2 hurricane continued on a west northwest track and its closes point to the country was at Half Moon and San Pedro Ambergris Caye on the October 26. Damage, if any was minimal, and there were no reported deaths.

The year 2011 saw no temperature records broken, rainfall was slight below normal with the month of April/May experiencing severe to extreme drought. During the hurricane season the country had the passage of one tropical storm and the nearness of Hurricane Rina. Both systems caused the country to go into emergency.