HWOSJU) issued by the National Weather Service San Juan forecast office for details. SHORT TERM...Today through Friday... At the mid levels, a drier airmass embedded in a ridge will result in relatively fair weather conditions for the first part of the short term cycle. Satellite derived products indicate below normal PWAT values for today and tomorrow. However, satellite imagery from GOES-16 shows fragments of moisture that will result in a few isolated showers during the morning hours. Afternoon convection will be limited, however, local effects and diurnal heating could spawn showers for parts of interior and northwestern sections of Puerto Rico. Showers that do develop will be short-lived and produce light rainfall amounts. Current model guidance suggest an increase in moisture content by Friday due to the passage of a weak tropical wave. PWAT values are expected to briefly reach above-normal values around 1.70 inches in the afternoon. At the upper levels, a westward-moving Upper Level Tropospheric Trough (TUTT) will generate favorable conditions to support deep convection across the forecast area. Hence, expect a more seasonal weather pattern, with diurnal shower activity and isolated thunderstorms over parts of northwestern Puerto Rico in the afternoon hours. Satellite imagery together with aerosol transport models suggest another Saharan dust cloud filter in the local islands. Thus, hazy skies will return once again under a warm easterly wind flow for the latter part of the short term period. LONG TERM...Saturday through Wednesday... No significant changes were introduced to the long-term forecast period, with the most recent model guidance supporting a generally stable and dry weather pattern with mid to upper level ridging as the dominant feature. Model-estimated precipitable water (PWAT) suggests below normal values of 1.60 inches or lower, with driest conditions expected by Monday, when PWAT are forecast to fall around 1.00 inches. Despite the expected conditions, localized convective development is still possible, favoring the northwestern quadrant of Puerto Rico and downwind from the local islands and El Yunque each afternoon. A high concentration Saharan dust event is anticipated for Saturday and Sunday, though lower concentrations are anticipated thereafter. Daytime highs are forecast to peak into the lower 90s across lower elevations and urban areas, with heat index that could reach the lower to mid 100s each day. Thus, expect hot and hazy conditions with reduced visibilities throught most of the period. AVIATION...VFR conditions are expected across all terminals through the 24 hour forecast period. No significant impacts to operations is anticipated. Winds will be up to 10KT gusting to 15-20KT from the E with sea breeze variations. Winds will decrease after 25/23Z. MARINE...Small craft operators should continue to exercise caution due to choppy seas up to 6 feet and/or winds up to 20 feet expected across the Caribbean waters and Mona Passages. Elsewhere, tranquil marine conditions with seas up to 5 feet and winds up to 15 mph will continue. A moderate risk of rip currents continues for all north-facing beaches of Puerto Rico, as well as some beaches along the south and east coast of Puerto Rico, Vieques, Culebra, and Saint Croix. && .PRELIMINARY POINT TEMPS/POPS... SJU 90 79 89 79 / 10 20 20 20 STT 90 81 90 81 / 10 10 10 30 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. && $$ $$