While the Atlantic basin remains quiet, the Pacific has exploded with a total of seven tropical cyclones active this evening, although all are fairly weak. Two are in the Eastern Pacific: Tropical Storm Greg and Tropical Depression Nine-E. One is in the Central Pacific – Tropical Storm Fernanda, which was previously a powerful Category 4 hurricane last week. Four are in the Western Pacific: Tropical Storms Noru and Kulap as well as Tropical Depressions 08W and 10W. A possible eighth tropical cyclone may join the “Pacific Seven” this weekend – Invest 99E in the Eastern Pacific is given an 80 percent chance of development within 48 hours, and a 90 percent chance within five days by the National Hurricane Center (NHC). Only 08W and 10W are imminent threats to land, and are expected to make landfall in China at only tropical depression strength.

Eastern Pacific: Greg not strengthening as anticipated, Nine-E likely to develop into a powerful Hurricane Hilary, 99E likely to become a tropical depression this weekend

Two tropical cyclones are currently active in the Eastern Pacific – Tropical Storm Greg and Tropical Depression Nine-E. Between the two tropical cyclones is Invest 99E, which is likely to develop into a tropical depression this weekend. None of the East Pacific systems are imminent threats to land.

Tropical Storm Greg, which was previously forecast to become a hurricane, has not strengthened as anticipated, and its low-level circulation has become exposed to the southwest of the  convective mass. As of 2:00 p.m. PDT (5:00 p.m. EDT), Tropical Storm Greg was centered near  14.9°N 120.7°W and was moving westward at about 13 mph. Maximum sustained winds were 45 knots (50 mph) with an estimated minimum pressure of 1003 mb. This is down from this morning’s intensity of 50 knots (60 mph) with a minimum pressure of 1001 mb, based on the fact that Greg’s low level circulation had become exposed. Greg could strengthen a little and hurricane strength cannot be ruled out, although it is no longer expected that Greg will strengthen into a hurricane.

Tropical Depression Nine-E, located south of the Gulf of Tehuantepec, is likely to gradually intensify into a hurricane by late this weekend or early next week. As of  2:00 p.m. PDT (5:00 p.m. EDT), Tropical Depression Nine-E was centered near  9.0°N 94.7°W and was moving westward at about 14 mph. While global models suggest that intensification over the next couple of days should be slow, statistical guidance shows the cyclone deepening faster. Nine-E is expected to be located over favorable conditions with low wind shear of less than 5 knots, a moist environment, and warm sea surface temperatures around 28-29°C (82.4-84.2°F) during the next few days. If Nine-E can quickly establish a core this weekend, rapid intensification seems likely, and major hurricane status is a strong possibility.

Invest 99E is located between Greg and Nine-E, and is given a high chance of development by the NHC. As of 18:00 UTC Friday, 99E was centered near 14.0°N 110.2°W with maximum sustained winds of 30 knots (35 mph). However, upper-level conditions are not as favorable for 99E to develop into a significant tropical cyclone in the short term. Regardless, global models indicate the potential for 99E to develop into a strong tropical cyclone in the long range.

Central Pacific: Fernanda likely to finally become a remnant low tomorrow night

Tropical Storm Fernanda emerged into the Central Pacific basin late yesterday and has slowly weakened due to unfavorable conditions of sea surface temperatures near 25°C (77°F) with wind shear stronger than 30 knots (35 mph). The Central Pacific Hurricane Center (CPHC) in Honolulu, Hawaii has taken over advisories on Fernanda as it has entered their area of responsibility. As of 11:00 am HST (5:00 p.m. EDT), Tropical Storm Fernanda was centered near 18.7°N 144.3°W and was moving westward at about 8 mph. Fernanda currently consists of an exposed low-level circulation with some deep convection to the northeast of the center. Fernanda is expected to weaken into a tropical depression overnight, and will likely to degenerate into a remnant low by the end of the day tomorrow. Fernanda is not expected to impact Hawaii as a tropical cyclone.

Western Pacific: Four weak cyclones, only one expected to strengthen much

Currently there are four tropical cyclones in the Western Pacific: Tropical Storms Noru and Kulap over the open western Pacific, Tropical Depression 08W in the South China Sea, and Tropical Depression 10W north of the Philippines. While Kulap, 08W and 10W are not likely to strengthen much, if at all, Tropical Storm Noru is predicted by the GFS and ECMWF models to become a strong typhoon far from land. The Joint Typhoon Warning Center (JTWC) predicts Noru will become a minimal typhoon equivalent to Category 1 on the Saffir-Simpson scale. Noru is likely to absorb Kulap as it is expected to be the stronger cyclone. The current high activity of the western Pacific is due to favorable upward motion as the result of the passage of the Madden-Julian Oscillation (MJO).

Tomorrow I will take a break from the Pacific and discuss the current conditions in the Atlantic, and will discuss when the next possible chance of Atlantic development may occur.