Monthly Weather Summary

NATIONAL METEOROLOGICAL SERVICE OF BELIZE

Climatologically, the Atlantic High Pressure ridge usually dominates the region during the month of April. Its orientation typically produces a dry southeasterly airflow across the country. At times heat-lows may develop across southern Mexico which causes pressure gradients to tighten over the area resulting in gusty winds. However, when the centres of these systems are over or very near the country, pressure gradients would instead slacken causing light winds and an excessively high heat-index. This overall synoptic pattern for the month normally corresponds with dry and warm weather. The only relief would come in the form of an occasional cold front. On average about two cold fronts would cross the country during the month. These may be accompanied by strong to severe thunderstorms and they are the main producers of the little rainfall for the month. April 2013 was characteristically warm and dry. In fact the dry was excessive with most stations recording far below their climatological norm (Table 1). This is likely due to the fact that only one relatively weak cold front crossed the country producing only minimal rainfall.

For the first three days in April the Atlantic high pressure ridge was the dominant low-level feature. It supported a dry and gusty east-southeasterly airflow with little to no rainfall over the country. By the 4^th a cold front was in the central Gulf of Mexico advancing southeastwards towards the country. Prefrontal activity resulted in isolated thunderstorms inland on this day and along some coastal areas and over the sea later in the night. The cold front crossed on the 5^th resulting in cloudy and cool weather with occasional light rain. By the following the day, the front was east of the country with a high pressure system in the Gulf extending a ridge southwards. This supported an east to northeasterly airflow with decreasing moisture and mainly fair and dry conditions.

The following four days (7^th to 10^th) would see mainly fair, warm, hazy and dry weather across the country as the Atlantic High Pressure Ridge coupled with heat/thermal lows over mainland Mexico supported a dry and sometimes gusty easterly to southeasterly airflow. A cold front would then approach once more on the 11^th but it only reached as far as the southern Gulf/ Bay of Campeche. The prefrontal activity, however, was enough to trigger off isolated showers and thunderstorms inland and an in the north. The front remained stationary in the Gulf the following two days (13^th and 14^th) while gradually dissipating.

The dominant synoptic pattern returned once more on from the 15^th to the 19^th of April. This translated in mostly fair, hazy, warm and dry weather with only an occasional afternoon thunderstorm inland.

Conditions became slightly moist on the 20^th as a cold front came as near as Northeastern Yucatan. This resulted in cloudy spells with a few showers affecting mainly inland and northern areas. Atmospheric conditions became mostly dry once more by the following day resulting in mainly fair, warm and dry weather. This lasted until the 25^th. On the 26^th the continental high behind a cold front north of the area produced a relatively moist East to Northeasterly airflow across the country. This produced cloudy skies at times with a few brief showers. These continued on the morning of the 27^th. By the 28^th the ridge had moved sufficiently eastward. This factor combined with thermal trofs redeveloping over Mexico supported a dry and warm east to southeasterly airflow which lasted until the end of the month. The only significant weather factor during this period was the development of isolated afternoon thunderstorms inland on the 30^th.

Table 1.