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Monthly Weather Summary



JUNE 2015


            Moist and unstable conditions prevailed during the Monday 1st as a northeasterly surface - low level flow developed in advance of a tropical wave. At the upper levels a west-northwesterly flow prevailed with a trough over the Gulf of Mexico and a ridge from the Eastern Pacific across Central America supported a diffluent pattern aloft. A low developed along the wave over the Gulf of Honduras by Tuesday 2nd with the associated trough extending north to near western Cuba. Light winds and land breeze effects added to coastal convergence. Twenty-four hour rainfall amounts of two to five inches were recorded at some stations across the country during Monday 1st and one to two inches Tuesday the 2nd.  

By Wednesday 3rd as the low tracked northeast towards northeast Yucatan, an upper level trough positioned over the southeastern Gulf of Mexico and maximum divergence shifted east of our area. Twenty-four hour rainfall amounts were significantly reduced. However during the Thursday 4th and Friday 5th a deep layer southerly flow resulted in showers and thunderstorms developing in the south over-night with light showers spreading north across the country through the early morning. As the 1013hPa low drifted to western Cuba and upper level trough positioned along eastern Yucatan and Belize, some rainfall continued to affect some areas during the Saturday 6th and Sunday 7th and increasing while affecting most aread during the Monday 8th with 24 hour rainfall in the order of 1-3 inches.

As another tropical wave approached, the resulting northeasterly airflow got upper level support from a west-southwesterly flow aloft. The tropical wave crossed Central America by Tuesday 9th and the axis of the upper level trough reposition east of Yucatan and Belize with a ridge across the Western Caribbean. Showers and thunderstorms over-night and into the early morning the Wednesday 10th were accompannied by strong and gusty winds up to 40 knots over northern and coastal areas.  During the Thursday 11th and Friday 12th the surface trough / tropical wave near northern Belize and Yucatan deepened and then developed into a low by the Saturday 13th. A diffluent west-southwesterly flow prevailed aloft and showers and thunderstorms developed inland and spread east towards the coast. Light rainfall continued to affect some areas of the country the next few days. 

The low moved into the Gulf of Mexico and eventually developed into Tropical Storm Bill by the Tuesday 16th while a tropical wave crossed Central America south of 17N. Improved weather conditions developed the next few days with only isolated showers or thunderstorms. This was as a result of a relatively dry and dusty 900-550hPa layer and a gusty east-southeasterly flow along with a convergent northwesterly flow aloft.

A few showers and isolated thunderstorms affected mostly the south during Thursday 18th but mainly fair weather with only isolated showers prevailed during Friday 19th through the Monday 22nd. Showers and thunderstorms increase over-night Tuesday 23rd into the Wednesday 24th as a surge in low level winds and moisture preceeded an approaching tropical wave. An upper level low over northwestern Yucatan provided upper level support in the form of a diffluent southwesterly flow. Moist and unstable conditions persisted over-night Thursday 25th into the Friday 26th with showers and thunderstorms again accompanied by squally conditions.

Relatively dry and hazy conditions prevailed during Friday 26th and Saturday 27th as a dry layer developed at low levels while conditions continued moist and unstable at the upper levels. Low level moisture increased during Sunday 28th while at upper levels a ridge to the west and trough east of the area supported a convergent northwesterly flow. Showers and thunderstorms affecting mostly the south of the country during night-time / early morning hours with lighter activity over the remainder of the country during the daytime and these conditions continued through the final days of June.    



M.  Gentle