Monthly Weather Summary, October 2020

National Meteorological Service of Belize

October is typically a wet month for the country of Belize, signaling the secondary peak of the rainy season over most areas and coinciding with the peak of the Atlantic Basin Hurricane Season. The second largest amount of historical tropical cyclones have also affected the country during the month of October. Additionally, other systems such as tropical waves, Upper Level Troughs (UTLs), Surface Troughs (SfTs) and occasional early season cold fronts and frontal shear lines influences the month of October's rainfall.

Being in the peak of the Atlantic Basin Hurricane Season, the month of October started off rather active with the developement of two tropical depressions (#25 and #26) that would later develop into Tropical Storm Gamma and Hurricane Delta, respectively, within the first week of the month. Conditions over Belize were moist and unstable during the 1st to the 3rd due to the development of a broad area of low pressure over the western Caribbean sea, an inverted trough east of the country, and tropical depression 25 east of Belize, enhacing a divergent upper level pattern over the area, supporting the development of showers and thunderstorms over the country. These showers and thunderstorms gradually decreased on the 3rd into the 4th with most activity occuring over offshore areas and the northern districts that were being supported by a stationary front over the Yucatan Peninsula. Lingering moisture over the area supported cloudy skies with mostly layered clouds and no significant rainfall activity. The proximity of these tropical systems resulted in a light westerly surface flow across the country which later became strong and gusty due to the approach of hurricane Delta that had formed to the south-southwest of Jamaica on October 6th. A feeder band from hurricane Delta resulted in moderate to heavy rainfall over the northern and some central portions of the country late night on Octover 6th into early morning on the 7th with the highest rainfall amount being recorded at the Tower Hill Station. Hurricane Delta quickly moved on a northwesterly path and by October 8th, was over the northwestern Gulf of Mexico before making landfall in Louisiana, United States. An Upper Level Cyclone along with a Northeasterly to Southwesterly oriented Upper Level TUTT overnight thunderstorms concentrated over the southern districts started over the Toledo district and progressing northward late night on Octover 8th into early morning on 9th October with the Punta Gorda station recording 80mm of rinfall.

Drier conditions prevailed from the 9th though to the 14th in week two over most areas with only isolated showers or thunderstorms developing. This was supported by a dry east to southerly suface flow and over the area. The upper level pattern throughout the period was primarliy neutral coupled with a relatively dry mid-upper levels. The wet spots during this period occured in the southern parts of the country around the 12 to 14 October as a result of an approaching tropical wave which was east of Belize and a moist northeasterly airflow due to troughing over the area. This tropical wave enhanced shower and thunderstorm activity in the south leading to 68.7mm of rainfall in Melinda on the 12th and 119.7mm of rainfall in Savannah on October 13. A moist northeasterly surface flow prevailed over the area along with an upper level trough, producing a southwesterly upper level flow and divergent conditions across the country from Octover 14 to 18 October. The increase in moisture and instability led to the development of a few showers and thunderstorms around the country, especially over central and southern areas. A second tropical wave crossed the country on October 19 leading to a few showers and thunderstorms over most areas of the country, decreasing to light periods of rain on the 20th.

Moist conditions persisted in the latter quater of the month as a broad area of low pressure developed over the west-central Caribbean that progressed westward towards the country on the 21st and 22nd, however, this system supported only brief and isolated showers. A west to southwesterly surface flow prevailed over the area supporting keeping most of the showery activity offshore associated with the braod low. During the 22nd-23, this system has a low chance of developing into a tropical cylone as it moved slowly north or northwestward. On October 24, however, the system started to become better organized and had a high chance of developing into a tropical cyclone. This system supported some showers over most areas of the country. The surface flow had shifted to a more east to northeasterly flow and dry conditions prevailed at the upper levels with a neutral pattern, except for over the extreme south of the country. By the early morning on the 25th, the broad low had developed into tropical storm Zeta which formed over the NW Caribbean and Zeta continues to rapidly streghten as developed into a hurricane late on the night of 26 October. Between October 27 to October 28, skies were cloudy over the area due to lingering moisture from Hurricane Zeta but shower and thunderstorm activity over the country were minimal, except for over the south. The month ended with pre-frontal activiy over the area due to an approaching cold front over the Yucatan Peninsula which supported some showers and periods of rain along with severe thundestorms over the south late night on the 28th into early morning on the 29th, resulting in the Punta Gorda station recording 109mm of rainfall. Rainfall gradually decreased over the south October 30 to 31 and isolated showers and thunderstorms were recorded elsewhere. Additionally, Tropical Depression 29 formed over the Central Caribbean Sea.

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 southern districts with normal to below normal rainfall recorded over the remainder of the country. In terms of maximum temperatures, the stations sampled show near normal to 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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Rainfall Observed: October 2020 (mm)

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Rainfall Observed: October 2020 (% Above/Below Average)

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