Cristina in Eastern Pacific no Threat to Land; TC 2 in Arabian Sea a Threat to Oman

The Eastern Pacific's third named storm of 2014 is here, as Tropical Storm Cristina spun into life late Monday night about 150 miles south of Mexico's Pacific coast. Satellite loops show that Cristina is still in the formative stages, but the combination of low wind shear and water temperatures that are a very warm 30°C (about 0.5°C above average) should allow Cristina to intensify into a Category 1 hurricane later this week. Cristina is headed away from Mexico, and it is unlikely that any watches or warnings will be required for this storm.

The formation of the Eastern Pacific's third storm of the season on June 10 comes nearly a month before the climatological average of July 5 for the usual appearance of the third storm. We've already had one hurricane in the Eastern Pacific this year (Category 4 Amanda, the strongest May hurricane ever observed in the Eastern Pacific), and the usual formation date for the second hurricane of the season is July 14. The 1981 - 2010 averages for the Eastern Pacific hurricane season are 15 named storms, 8 hurricanes, and 4 major hurricanes. NOAA's pre-season prediction for the Eastern Pacific hurricane season, issued on May 22, is calling for an active season, with around 17 named storms, 9 hurricanes, and 4.5 major hurricanes. This year is shaping up to be an El Niño year, and El Niño conditions typically increase the seas surface temperatures and decrease the vertical wind shear over the tropical Eastern Pacific, favoring the development of more and stronger tropical cyclones.


Figure 1. Latest satellite image of Cristina off the Pacific coast of Mexico.

Tropical Cyclone Two a threat to Oman
The North Indian Ocean has some activity today in the form of Tropical Cyclone Two, a tropical storm with 45 mph winds that has formed in the Arabian Sea. Tropical Cyclone Two is expected to head west-northwest toward Oman and intensify into a Category 1 storm later this week, though the intensity forecast is a difficult one, due to moderate wind shear of 15 - 20 knots and the presence of dry air. The North Indian Ocean has two tropical cyclone seasons--one in May and June before the Southwest Monsoon arrives, and one in October - November after the Monsoon has departed.


Figure 2. True-color MODIS image from the Terra satellite of Tropical Cyclone Two over the Arabian Sea taken at approximately 6:30 am EDT June 10, 2014. The storm appears to be pulling in a plume of dust or pollution from the north, flowing off the coast of India (some sunglint reflecting off the water is making it difficult to tell for sure.) The coast of Oman can be seen at the left side of the image. Image credit: NASA.

Quiet in the Atlantic
There are no tropical cyclone threat areas in the Atlantic to discuss today, and none of the reliable models for forecasting tropical cyclone genesis are predicting development over the coming five days. Strong upper-level winds, associated with the subtropical jet stream, are bringing high levels of wind shear over the tropical Atlantic and Gulf of Mexico, and these high winds are forecast to persist for at least the next six days. The GFS model continues to predict that about 7 - 10 days from now the upper level winds over the Western Caribbean will relax and low-level moisture will build, potentially allowing a tropical disturbance with heavy rains to develop there. However, the European model keeps the wind shear high over the Western Caribbean early next week, so any development in the region remains in doubt. Arguing against any development in the Atlantic is the anticipated strengthening next week in the West-Central Pacific Ocean of the Madden Julian Oscillation (MJO), a pattern of increased thunderstorm activity near the Equator that moves around the globe in 30 - 60 days. An active MJO in that part of the tropics tends to bring large-scale sinking motion to the tropical Atlantic and increased wind shear, which puts a damper on the chances of tropical storm formation in the Atlantic. The MJO is predicted to drift slowly eastwards into the Eastern Pacific by late June, which will tend to keep odds of tropical storm formation lower than average in the Atlantic into late June.

Jeff Masters