Barbara, the second named storm of the 2019 Pacific hurricane season, formed on Sunday morning, and is likely to become the second hurricane and possibly the first major hurricane of the season. It is possible that Barbara could enter the Central Pacific basin in about a week, but it remains too soon to tell if it will affect the Hawaiian Islands. Barbara formed about five days later than the climatological average for the second named storm in the eastern Pacific basin.

As of 9:00 a.m. MDT (11:00 a.m. EDT), Tropical Storm Barbara was centered near 10.6°N 110.4°W, and was moving west-northwestward at 16 mph. Maximum sustained winds were 35 knots (40 mph), with an estimated minimum pressure of 1006 mb. Barbara was named Sunday morning after the convective pattern became better organized and an overnight scatterometer pass showed wind barbs of tropical storm force. Barbara is not particularly well organized at the moment, with the center of circulation near the northern edge of the convective overcast. Shear is currently low to moderate (about 10-15 knots), but is expected to decrease to less than 10 knots in about 36 hours and remain low for the next several days. Intensification should be gradual today, but it is possible a more rapid intensification period could commence tomorrow. Barbara is currently located over warm sea surface temperatures (about 29°C/84.2°F) and is embedded in a moist environment (mid-level relative humidity values above 70 percent). However, by late this week, sea surface temperatures are expected to drop to around 26°C (78.8°F) while mid-level relative humidity values drop to around 55 percent, which should slow intensification after that point.

The global models disagree on Barbara’s intensity as it approaches the Central Pacific basin (west of 140°W), with the GFS significantly weakening Barbara as it enters the basin and the ECMWF maintaining a powerful hurricane for ten days. The GFS model is also north of the ECMWF and shows Barbara tracking over cooler waters. A few degrees in latitude could make a difference whether Barbara is a remnant low or a major hurricane entering the Central Pacific basin. As noted above, it remains way too soon to tell if Barbara will pose any threat to the Hawaiian Islands. Regardless, interests in Hawaii should continue monitoring the progress of Barbara.

Another system behind Barbara to watch for development

In a few days, another area of low pressure is expected to form south of Mexico. The National Hurricane Center (NHC) gives this system a near zero percent chance of development within 48 hours, and a 40 percent chance within five days. The next name on the eastern Pacific naming list is Cosme.

The Atlantic basin remains quiet with no tropical cyclones likely to form for at least during the next five days. For the second year in a row, no tropical cyclones will have formed in the Atlantic basin during the month of June. However, this is not necessarily a sign for a quiet season.