Monthly Weather Summary, January 2021

National Meteorological Service of Belize

January is climatologically the coolest month of the year and falls at the middle of the cool transition period of the dry season for Belize. Rainfall during the month is normally attributed to the passage of frontal systems that progresses southward from the continental United States and upper and surface troughs. Typically, an average of twelve cold fronts, two stationary fronts and one warm front would crosses Belize for the month but in January 2021, an average of one front every 14 days crossed the country, with a few weak fronts passing north of the area.

The first week in the month started off relatively dry due to limited low and upper level moisture, supported by a strong high pressure ridge, extending into the Caribbean basin from the Bermuda high. This pattern suppressed rainfall activity over Belize between January 1 and 2 and 6 and 7, resulting in generally isolated showers across the country, despite a divergent upper level pattern. The slightly moist period was between January 3 to 5 as a result of the approach of a frontal system that saw a slight increase in low level moisture over the area supporting isolated showers and thunderstorms, mostly over inland areas. Little to no rainfall was observed elsewhere with a predominantly east to south-easterly low level airflow which became east to north-easterly as the front approached and passed north of the country. A persistent upper level anti-cyclone supported a south-westerly wind component in the upper levels.

On January 8, in the second week, a strong, fast moving front approached and crossed the country before becoming stationary over the Gulf of Honduras, with a strong ridge building behind the front and persisting over the north-west Caribbean. The passage of the front led to a cool, dry and light north and north-westerly airflow though to January 14. Upper level conditions continue to be relatively dry with a south-west wind component during this week and an anticyclone as the main upper level feature. Neutral conditions prevailed during the period, inhibiting any significant convection over the area with only isolated thunderstorms developing over inland areas during the passage of the front. Low level moisture increased further between January 11 and 14 due to the presence of a surface trough over the country. This surface trough supported an increase in cloudiness, a few showers and periods of light rain in the latter part of the week.

A dry period followed in the third week, with no significant rainfall activity reported and a few cloudy spells between January 15 and 18. Most of the moisture continued to be concentrated in the low levels as a stationary front passed north of the country on January 16. On January 18, however, moisture over the area began to increase in both the low and upper levels due to a moisture north-easterly surface airflow, supported by a another stationary front over the Yucatan Peninsula. This increase in moisture supported cloudy to overcast skies across the country with multilayered clouds producing periods of rain over most areas through to the 20th before becoming isolated. A neutral to weakly convergent upper level pattern was observed during the period, thus no significant deep convection was noted, coupled with a light and variable upper level wind component. At the end of the week, a drying out of the upper levels was observed and only isolated showers was noted over southern districts.

Conditions became even drier over the area in the last week, with little to no moisture available for rainfall or cloud development. This decrease in moisture lasted until January 28 as a result of a strong Bermuda high pressure ridge extending into the Caribbean and over the north-west Caribbean. The pressure gradient over the area was tight due to a low pressure system over Columbia interacting with the Bermuda high pressure ridge. Over Belize, the tight gradient supported a moderate to occasionally gusty east to southeast surface airflow. A ridge pattern was also analyzed at the upper levels supporting a south-westerly component between January 22-28 before veering and becoming north-westerly to zonal in a neutral to weakly divergent environment. Weather conditions during this week was fair and relatively dry with only isolated showers being observed up until January 27, then a few showers and periods of rain affected most areas on January 28, with cloudy spells and periods of light rain persisting through to January 30. Fair and dry conditions returned to end the month on January 31.

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, rainfall was above normal over the northern and some central locations of the country due to the passage of one strong cold fronts across the country and the approach of several other frontal systems that passed north of the area and a surface strong that persisted over the area in the third week. Below normal rainfall was also observed over the southern areas of the country. In terms of temperatures, most of the stations sampled show below slightly above normal maximum/daytime temperatures, while minimum/nighttime temperatures were above normal for all the stations except for Punta Gorda in the south.

Monthly Rainfall Summary

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Monthly Maximum Temperatures

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Monthly Minimum Temperatures

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