Monthly Weather Summary, June 2021
National Meteorological Service of Belize
June marks the start of the 2021 wet/Atlantic hurricane season and is typically the month where most stations observe their fist rainfall peak in the annual cycle. By June, the rainy season had officially started across the country. Despite the early start of the 2021 rainy season which started around mid-May for most areas, the month of June saw a dry spell across most areas. Rainfall is typically attributed to Upper Level Troughs, Surface Troughs, Tropical waves, Tropical storms and Hurricanes which moves westward through the Caribbean and. An average of two upper-level troughs, four surface troughs, one mid to upper level low and fifteen tropical waves would pass over the country in June, however, only two surface troughs and four tropical waves crossed the country with two of the TW being weak.
After the early start of the 2021 rainy season, the country began to go through a dry spell as ridging dominated the area. Low and upper level moisture was minimal with subsidence for the first two days of week one and this supported mainly fair weather and isolated showers. Despite a slight increase in low level moisture for the remainder of the week, ridging and continued subsidence at the upper levels kept showers and thunderstorm activity isolated and brief over the country. The ridge supported a light to moderate easterly surface flow while a TUTT low over the central Cuba extending to the southwest Caribbean produced a north-westerly wind component at the upper levels.
An increase in low level moisture continued in week two due to a surface trough over the Yucatan and southern Mexico, however, the North Atlantic Ridge was the dominant feature over the Caribbean Basin. At the upper levels, conditions also became moist and neutral to weakly divergent leading to an increase in showers and thunderstorm activity overnight and early mornings over most areas of the country, especially over southern areas. This activity was enhanced by an anti-cyclone over the area giving upper level outflow and a tropical wave advecting moisture over the country as it approached the area. The upper levels winds were primarily north-westerly during this period becoming west to south-westerly at intervals.
Moist and unstable conditions continued into week three over the country as a low-pressure system developed over southwestern Mexico, west of Belize, which later became potential tropical cyclone number three. The passage of a tropical wave across the country on June 15 to 16 further enhanced instability and moisture over the country. This moisture and instability extended through to the upper levels with an upper-level anti-cyclone producing a north to north-westerly flow. Divergent conditions at the upper levels provided outflow and supported the development of deep convection over most areas from June 15 to June 19 leading to the development of showers and thunderstorms, especially over the Orange Walk, Cayo, Stann Creek and Toledo districts due to the tropical wave. As potential tropical cyclone three which became tropical depression Claudette moved further away from our area and impacted south-eastern United States and the tropical wave continued westward, moisture levels in the upper levels decreased with only some residual low-level moisture, resulting in drier conditions across the country. The upper levels also became neutral to weakly convergent. Riding supported an east to south-easterly airflow over the area and only isolated showers and thunderstorms prevailed on June 20 and 21, despite another weak tropical wave crossing on June 20th.
During the last week of June, two weak tropical waves traversed the area and crossed over Belize on June 22 and June 27. Relatively moist conditions prevailed in the low levels during this period with a dry spell om June 23 and 24 as the North Atlantic High-Pressure Ridge extended over the Caribbean. The ridge pattern over the area supported an east to south-easterly moderate to occasionally gusty surface flow. At the upper levels, the anticyclone over Mexico supported a north to north-westerly wind component, except for June 27 where the flow was south-westerly, and conditions were mostly moist through to the end of the month. The upper-level pattern was neutral to weakly convergent supporting only isolated showers and thunderstorms across the country, except for a few more over some southern and central locations. With the passage of a tropical wave on June 27 and a mid-level low which was reflected near the surface over the Honduras/Nicaragua border, a few showers, thunderstorms, and periods of rain were observed over most areas starting in northern and central locations early morning and spreading to inland and southern areas by the afternoon. A divergent pattern at the upper levels provided outflow for these thunderstorms to develop. The moist and unstable conditions persisted to the end of the month.
The graph and maps below summarize the total rainfall and average maximum and minimum temperatures. They also give an indication of how these readings compare to the normal for the month across the stations sampled. As can be seen, the country suffered from several dry spells with rainfall being mostly attributed to low levels moisture and a few tropical waves/surface troughs. Thus, rainfall was below normal over most areas. In terms of temperatures, most of the stations sampled show near normal to slightly above normal maximum/daytime temperatures, while minimum/night-time temperatures were near normal to slightly above normal for most the stations except for the Towerhill, Belmopan and Punta Gorda stations were below normal night-time temperatures was observed.Monthly Rainfall SummaryMonthly Maximum TemperaturesMonthly Minimum TemperaturesRainfall Observed: June 2021 (mm)Rainfall Observed: June 2021 (% Above/Below Average)