The Atlantic is finding its footing this week with three systems expected to organize in the days ahead while Hurricane Hilary in the eastern Pacific is poised to unleash torrents of rain across parts of Southern California early next week as a weakened but still potent storm system.
The two areas farthest east in the Atlantic – now designated Invest 98L and 99L by the National Hurricane Center – both have greater than 50/50 odds at becoming a tropical depression by the weekend. As we discussed in Wednesday’s newsletter, these two low pressure systems are embedded within an broader strip of low pressure extending from Africa southwestward to the central Atlantic. It’s unclear where within this broader region of low pressure and storminess each will form, but the system farthest east (Invest 98L) will be limited by dust-laden air as it curls northwestward toward open Atlantic waters.
Interests in the Lesser Antilles of the eastern Caribbean will want to monitor the progress of Invest 99L, the westernmost disturbance. Our forecast models show a small chance of it or another disturbance to its west slipping far enough west to impact parts of the Leeward Islands by late weekend. Development, if it occurs, should be slow and for now we’re not anticipating a significant threat.
Meanwhile, we’ll be keeping an eye to the Gulf of Mexico this weekend as the northern edge of a tropical wave currently moving through the central Caribbean gets tangled up with a washed-out cold front. The interaction could produce a short-lived tropical system in the north-central or northwestern Gulf next Monday or Tuesday.
Regardless of development, the system will be headed toward Texas where rain and rain-cooled air are desperately needed. We’ll want to monitor the forecast trends since waters are especially warm right now, but the threat remains low.
The big tropical story next week won’t be in the east, but rather across parts of Southern California and the desert southwest.
Hurricane Hilary – quickly on its way to becoming a powerful storm – will be traveling up the coast of the Baja California peninsula of northwestern Mexico and is expected to accelerate toward Southern California by late Sunday into Monday. The much cooler waters near the coast of California are expected to rapidly shut off Hilary’s tropical engine, but it will remain a potent storm system, bringing boatloads of tropical air and rainfall to Southern California, western Arizona and Nevada through next week.
The rainfall totals suggest the potential for a high-impact event, with extensive flooding across the region, especially in the hilly terrain and along east-facing mountains which can worsen the heavy rain.
Regardless of Hilary’s status as a tropical system, gusty winds will be a compounding issue, with winds amplified through the valleys and passes. Residents across the region should monitor the forecasts closely in the coming days.
