The tropics are coming to life in the Northern Hemisphere this weekend. At 5:00 PM EDT (4:00 PM CDT local time), Tropical Depression Three-E was designated in the East Pacific. Three-E is the third tropical cyclone of the 2017 Pacific hurricane season. In addition, Tropical Storm Merbok was named by the Japan Meteorological Agency (JMA) in the South China Sea, making it the second named storm of the 2017 Pacific typhoon season.

TROPICAL DEPRESSION THREE-E (EAST PACIFIC)

The National Hurricane Center (NHC) initiated advisories on Tropical Depression Three-E Sunday afternoon. The designation was based on an ASCAT pass that revealed the presence of a well-defined circulation and winds just under 30 knots (35 mph). At 4:00 PM CDT (local time), Three-E was centered near 14.5°N 95.0°W, and was moving northwest at 5 mph. The official intensity from the NHC was 30 knots (35 mph), but this afternoon’s ASCAT pass showed maximum winds just over 25 knots (30 mph) and the official intensity could be a bit generous. The estimated minimum pressure was 1007 mb. Three-E’s convective activity is somewhat limited, though, and has actually decreased this afternoon. The official NHC forecast only predicts slight strengthening, although the cyclone is forecast to become Tropical Storm Calvin by tomorrow. I think that Three-E might not even manage to make landfall in Mexico as a tropical cyclone due to its proximity to land. The GFS and ECMWF models both show Three-E/Calvin dissipating by Tuesday afternoon. Three-E is expected to continue the East Pacific’s active, but weak, start. The primary threat from Three-E, much like Tropical Storm Beatriz earlier this month, is heavy rains.

TROPICAL STORM MERBOK (WEST PACIFIC) 

Saturday evening, Tropical Depression 04W was designated in the South China Sea, and was named Tropical Storm Merbok this morning. At 18:00 UTC Sunday afternoon, Merbok was centered near 19.5°N 115.9°E, and had 1-minute maximum sustained winds of 35 knots and 10-minute maximum sustained winds of 40 knots. The estimated minimum pressure from the Joint Typhoon Warning Center (JTWC) was 999 mb.  Much like Three-E, Merbok is not likely to strengthen much at all, since landfall is likely in Southeastern China on Monday. Merbok is the second named storm of the 2017 Pacific typhoon season, which has had a slightly below average beginning to the season.

ATLANTIC ABOUT TO GET ACTIVE? 

The 12z Sunday GFS, ECMWF, CMC and NAVGEM runs all continued to indicate the possibility of the Atlantic’s next tropical cyclone forming in a week or so, in either the Western Caribbean or Gulf of Mexico, as a result of a large monsoon gyre. However, the models have backed off intensity a bit from last night’s runs, and have also begun to suggest development may not occur until the low reaches the Gulf of Mexico. The future track of this tropical cyclone, if it develops, is way too soon to forecast, with models showing both a Bay of Campeche and Northeast Gulf of Mexico track. I continue to give a 40 percent chance of Tropical Storm Bret forming in this region during the next ten days. Like I said yesterday, if something does develop, I expect it to be “big and messy” due to moderate to strong wind shear – more of a rainmaker than a traditional tropical cyclone. A hurricane is unlikely with this system if it does develop.

I will be back for another blog post tomorrow on these systems – the tropics are really beginning to heat up globally. The Atlantic should be next.