Valid Time: Monday–Sunday July 11 – July 18, 2011
Feature(s) of Interest: A tropical wave (TW) interacting with an upper level low is producing widespread convection and intense thunderstorms in the quadrant west of 80W and south of 20N to the coast of Central America and Belize this morning. The active TW was located near 81-82W heading west at 10 mph (see Fig. 2 and Fig. 3 below). This TW is forecast to reach the coast of Belize and Yucatan on Tuesday evening, just ahead of a surge in the low level easterly flow in the western Caribbean (see Fig. 4 below). Precipitable water values are high over Belize and the NW Caribbean, ranging from 50-55 mm this earlier morning. Consequently, the excess moisture and instability generated by the approaching tropical wave will continue to produce widespread outbreaks of showers and thunderstorms over Belize during the next 48 hours, with a slight decrease in the convection on Thursday. However, the unsettled weather will return on Friday through the up-coming weekend induced by a surface low pressure system over the NW Caribbean near Belize, interacting with an upper level trough.
Daily rainfall totals will range from 1–2 inches especially along coastal areas and the South at first. The rains will become more concentrated in the North and NW on Friday through the weekend. Orography will enhance the daily rainfall amounts in the Cayo, Stann Creek and Toledo districts during the next 48 hours, with daily totals near 2-3 inches is some areas. River levels over the Toledo and Stann Creek districts are already at flood stage, and additional runoff lead to floods and flash floods in some localities. Residents in low lying communities should remain vigilant and motorists should be aware of localized flooding of some feeder roads.
We continue to monitor a vigorous TW in the Atlantic, some 600 miles east of the southernmost Windward Islands this morning. This system is generating some intense thunderstorms as it drift westwards at 15-20 mph. The NHC is giving this disturbance a 10% chance of becoming a tropical cyclone during the next 48 hours.
Elsewhere over the North Atlantic Basin, tropical cyclone formation is not expected during this working week, as conditions in the atmosphere remain unfavourable!
