Tropical Storm Daniel forms, expected to become a hurricane; Emilia to follow behind
The fourth named storm of the 2012 Pacific hurricane season, Tropical Storm Daniel, has arrived. As of the latest advisory from the National Hurricane Center, maximum sustained winds were up to 45 mph and the minimum barometric pressure was down to 1002 millibars. The system was moving towards the west-northwest at 12 mph. Visible satellite loops reveal that Daniel has become much better organized over the past 24 hours, with the center of circulation tucked deep within a circular Central Dense Overcast. Recent satellite intensity estimates were 3.7 from UW-CIMSS and 3.5/3.5 from NESDIS' Satellite Analysis Branch. Either way you slice it, Daniel is much stronger than indicated and will likely attain hurricane status by tomorrow morning.
Figure 1. Morning visible satellite imagery of Tropical Storm Daniel.
The forecast for Daniel
Nothing is new with the track forecast. Daniel is expected to continue towards the west northwest over the next 24 hours or so before turning towards the west as the ridge of high pressure responsible for the extreme heat over the United States begins to intensify and build towards the west. This motion is expected to continue through 120 hours out as the high remains strong. Model guidance continues to indicate that remnant moisture from the tropical storm may impact Hawaii thereafter, but Daniel is not expected to be a tropical storm at that time.
The intensity forecast has become a little more difficult today simply because Daniel has unofficially strengthened more than originally anticipated. Due to the fact that the intensity estimates aforementioned are unofficial, the initial intensity of 45 mph will be used below. The recent quick intensification will be noted afterwards. My forecast shows Daniel reaching Category 1 hurricane status by tomorrow morning and peak intensity by 48 hours out. A combination of slightly higher wind shear and dramatically cooler Sea Surface Temperatures after 48 hours out should allow for gradual weakening.
...FORECAST POSITIONS AND MAX WINDS...
INIT 05/1500Z 14.2N 110.5W 40 KT 45 MPH
12H 06/0000Z 14.6N 112.1W 60 KT 70 MPH
24H 06/1200Z 15.0N 114.3W 65 KT 75 MPH
36H 07/0000Z 15.3N 116.4W 70 KT 80 MPH
48H 07/1200Z 15.5N 118.6W 75 KT 85 MPH
72H 08/1200Z 16.0N 123.0W 70 KT 80 MPH
96H 09/1200Z 16.5N 128.0W 60 KT 70 MPH
120H 10/1200Z 17.0N 134.0W 45 KT 50 MPH
Elsewhere in the tropics
The Atlantic basin is quiet with no areas of interest in the National Hurricane Center Tropical Weather Outlook. Tropical wave is interacting with a TUTT, producing disorganized thunderstorm activity over the northeast Caribbean Sea. This area is no threat to develop as it heads west-northwest.
An area of low pressure several hundred miles south of the Mexican coastline is producing disorganized shower and thunderstorm activity. Models continue to indicate that this disturbance will eventually become a hurricane, but will pose no threat to land. The National Hurricane Center is currently giving this area a low chance, 20%, of becoming a tropical cyclone over the next 48 hours: I believe these chances are slightly higher at 30%.
Elsewhere, tropical cyclone development is not likely over the next 48 hours.