Monthly Weather Summary, August 2018
National Meteorological Service of Belize
Monthly weather summaries are prepared by the climate section of the National Meteorological Service of Belize. The NMS of Belize maintains a network of over 25 weather stations that are situated primarily in the agricultural regions of the country. Temperature and rainfall are read at 9 am each morning and the rainfall total read at this time represents the accumulated rainfall for the previous day.
Climatologically speaking, August is known for its two weeks dry spell known locally as the "maga season". As a result, a marked drop in rainfall can be seen around August when looking at the annual rainfall distribution for the country. Weather systems that typically affect Belize during the month of August are Tropical Waves (TWs), Tropical Upper Tropospheric Troughs (TUTTs) and an occasional Tropical Cyclone (TCs) (tropical depression, tropical storm or hurricane).
August 2018 was unusually wet over central coastal areas (Belize District) and southern areas (southern Toledo district). The north and northwestern portions ( Corozal, northwest Orange Walk and Northwest Cayo) were dryer than normal while the remainder of the country saw rainfall totals within their normal range.
Although a couple tropical waves crossed the country during the first five days (2nd and 4th) of August 2018, rainfall was typically less than 1 inch per day for most areas. One exception was southern Belize where some showers and thunderstorms on the night of the 1st through early morning on the 2nd produced up to 87 mm of rainfall in Punta Gorda. However, in general upper level conditions supported a generally convergent and subsident pattern at the mid to upper levels during this period. This was produced by ridging to the west of the area and the axis of a TUTT east of the country. Overall showers and thunderstorms were generally isolated. Activity was diurnal with slightly more affecting the south during the nighttime and inland areas during the afternoon hours.
Upper level conditions changed gradually during the period from the 6th to the 8th of August as the axis of the TUTT slowly shifted north and west of the area. The south was first to experience divergent conditions aloft. This resulted in showers and thunderstorms on the 6th which produced up to 57.0 mm of rainfall in Punta Gorda. The activity shifted northward during the next couple of days with the airport receiving 40.4 mm on the 7th and 51.6 mm on the 8th. The activity on the 8th was due to the passage of a tropical wave under the aforementioned favourable upper dynamics resulting in deep-layered moisture and instability over the area. Moisture decreased gradually on the 9th.
Conditions were generally fair across the country between the 10th and 12th of August. However, nighttime showers and thunderstorms continued affecting the south producing approximately 1 inch of rainfall per day during this period.
Conditions became more moist and unstable on the 13th with a few showers and thunderstorms across the country. Highest amounts were once again recorded in Punta Gorda with 80 mm of rainfall. This activity decreased on the 14th and generally fair weather was experienced on the 15th. A weak tropical wave crossed that day but did not produce any significant rainfall across the country.
The upper levels became gradually more divergent during the next few days from the 16th to the 18th resulting in some showers, thunderstorms and periods of rain over most areas by the 18th. Activity was once again highest over the south where Punta Gorda recorded 67.8 mm and 47.0 mm of rainfall on the 17th and 18th, respectively.
Relatively moist conditions persisted for the following few days from the 19th to the 24th. Tropical waves crossed the country on the 19th, 21st and 23rd of the month. However, activity over the country was generally diurnal with showers occurring mainly over southern and coastal areas during the late night to early morning hours and inland areas during the afternoon hours with peak daytime heating.
A stronger tropical wave crossed the country on the 25th under very favourable upper level conditions supporting a further increase in moisture over the country. This resulted in torrential rainfall over the south on the night of the 25th which caused flooding and road closures. Records from Punta Gorda show a total of 174.6 mm of rainfall on the 24th and an additional 87.6 mm on the 25th. This activity then moved up to central areas of the country (Belize City/ Ladyville area) on Sunday 26th August where a total of 160.5 mm of rainfall was recorded at the airport. It is worth noting that this single amount of rainfall, which fell within a few hours, is just over an inch short of the typical August average for the airport which is 193.7 mm.
A couple tropical waves crossed the country during the period from August 27th to 29th causing relatively moist conditions to persist over the area and producing a few showers and thunderstorms across the country but mostly over the south. Conditions, then, became generally fair during the last two days of the month.
Based on analyses from the National Hurricane Center a total of 10 tropical waves crossed the country during the month of August 2018. The strongest of these was the wave that crossed on the 25th with a moisture plume trailing behind causing intense activity through to the 26th (see the discussion above).
The graph and maps below summarize the total rainfall and average maximum and minimum temperature recorded during the month of August 2018. They also give an indication of how these readings compare to the normal for the month across the stations sampled. As can be seen, August 2018 was unusually wet over central coastal areas (Belize District) and southern areas (southern Toledo district). The north and northwestern portions ( Corozal, northwest Orange Walk and Northwest Cayo) were dryer than normal while the remainder of the country saw rainfall totals within their normal range. In terms of maximum temperatures, most of the stations sampled here saw slightly below normal maximum temperature in August 2018. The only exception was Pomona. Meanwhile nighttime temperatures were slightly warmer than normal for most stations except for Pomona and Punta Gorda.
Monthly Rainfall Summary
Monthly Maximum Temperatures
Monthly Minimum Temperatures