Daniel further strengthens into a Cat 2; Emilia forms, expected to become a hurricane

By: TropicalAnalystwx13 , 3:44 AM GMT on July 08, 2012

Daniel has made the most out of its short time over warm water, and has unexpectedly strengthened into a Category 2 hurricane on the Saffir-Simpson Hurricane Wind Scale. As of the latest advisory from the National Hurricane Center, Daniel was located at 14.9 °N 121.2 °W (position accurate within 20 nm), or about 920 miles southwest of the southern tip of Baja California. Maximum sustained winds have increased to 105 mph and the minimum barometric has fallen to 969 millibars. Daniel is moving towards the west at 14 mph well away from land. Visible satellite loops over the past three hours have shown a well-defined, clear eye with cold cloud tops below -70 °C wrapping nearly 2/3 of the way around it. Recent frames however has shown hints of dry air entrainment in the southeast quadrant of the eyewall, and the eye has become increasingly cloud-filled. NESDIS' Satellite Analysis Branch (SAB) showed 4.5/90 mph at 00 UTC, with NHC's Tropical Analysis Forecasting Branch (TAFB) showing 5.0/105 mph, and UW-CIMSS ADT at 5.6/120 mph. Daniel has almost certainly peaked in intensity at this time.

Figure 1. Evening visible satellite imagery of Hurricane Daniel.

The forecast for Daniel
As aforementioned, Daniel is moving due west at 14 mph. This motion should continue over the next 5 days as the strong mid-level ridge of high pressure to the north of the cyclone builds westward. 00Z model guidance runs revealed a shift northward in track, showing a pass just south of the island of Hawaii by 144 hours out. The National Hurricane Center track forecast required a shift northward in the latest advisory, but still lies a bit farther south and west than the model guidance. Daniel may reach the Central Pacific Hurricane Center's area of responsibility by late Tuesday night, but the system is expected to be a minimal tropical storm at that time, and should not make a direct impact on the island of Hawaii. Regardless, increased rainfall chances are depicted in the local National Weather Service' warning area, and gusty winds over 20 mph can be expected by next weekend.

Daniel will be crossing the 26 °C isotherm overnight, meaning the storm has almost certainly peaked in intensity. The 00Z SHIPS file update revealed rapidly declining Relative Humidity values, indicative of an increasingly dry environment. In addition, Sea Surface Temperatures will begin to rapidly fall over the next day. A combination of these two factors reveals that Daniel should steadily weaken through the forecast period, falling below hurricane status within 48 hours and below tropical storm status within 120 hours. The official National Hurricane Center intensity forecast shows Daniel becoming a post-tropical cyclone or remnant low by 120 hours. Given the unexpected intensification this afternoon, Daniel may be able to sustain itself as a tropical cyclone for slightly longer, as depicted in the below forecast. This lies slightly above most of the model guidance.


INIT 08/0300Z 14.9N 121.2W 90 KT 105 MPH
12H 08/1200Z 15.1N 123.1W 85 KT 100 MPH
24H 09/0000Z 15.4N 125.7W 85 KT 100 MPH
36H 09/1200Z 15.7N 128.5W 70 KT 80 MPH
48H 10/0000Z 15.9N 131.4W 60 KT 70 MPH
72H 11/0000Z 16.1N 137.7W 45 KT 50 MPH
96H 12/0000Z 16.3N 143.9W 40 KT 45 MPH...CPHC AOR
120H 13/0000Z 15.8N 149.8W 35 KT 40 MPH

Tropical Storm Emilia forms
Later this evening, Invest 97E was reclassified as Tropical Depression Five-E. The tropical depression has just been upgraded to a tropical storm based on impressive banding features and a convective ring shown on geostationary and microwave imagery. As for specifics, Emilia was located at 10.7 °N 103.2 °W (position accurate within 45 nm), or about 580 miles south of Manzanillo, Mexico. Maximum sustained winds have increased to 40 mph and the minimum barometric pressure has fallen to 1003 millibars. The cyclone was moving towards the west-northwest at 16 mph. NESDIS' Satellite Analysis Branch (SAB) and NHC's Tropical Analysis Forecasting Branch (TAFB) showed 2.0/35 mph at 00 UTC and UW-CIMSS ADT is up to 2.6/45 mph as of 02:15 UTC. Continued strengthening is almost a certainty.

Figure 2. Evening un-enhanced infrared imagery of Tropical Storm Emilia.

The forecast for Emilia
The track forecast for Emilia is just as straightforward as it was for Daniel. The cyclone is expected to continue towards the west-northwest for the rest of the forecast period, before turning westward thereafter as the mid-level ridge to the north, the same one responsible for steering Daniel westward towards, or just south, of Hawaii builds westward. This is a higher-than-average confidence forecast due to excellent model agreement. The forecast below lies just north of the official National Hurricane Center track forecast, which lies on the south-central end of the model guidance.

The environment could not get much more favorable than the one Emilia will be within over the next 96 hours. Wind shear is expected to remain below 10 knots for a majority of the period, with Sea Surface Temperatures above 27 °C through 120 hours. Relative Humidity values above 70% are expected to continue through 96 hours before rapidly dropping off before then, which will likely induce weakening. Until then however, there is no reason to think that Emilia will not become a powerful hurricane over the next four days. The SHIPS model gave Emilia a whopping 90% chance of 25-kt rapid intensification, an amazing 73% chance of 30-kt rapid intensification, and an unheard of 63% chance of 35 and 40 kt rapid intensification. The current National Hurricane Center forecast remains extremely conservative given all of the intensity parameters, with a peak intensity of 100 mph in 72 hours with weakening thereafter. My forecast lies well above the NHC's and model guidance, showing the system reaching Category 4 intensity in 72 hours. This is a very low confidence forecast.


INIT 08/0300Z 10.7N 103.2W 35 KT 40 MPH
12H 08/1200Z 11.3N 105.1W 45 KT 50 MPH
24H 09/0000Z 12.1N 107.6W 65 KT 75 MPH
36H 09/1200Z 12.9N 109.9W 90 KT 105 MPH
48H 10/0000Z 13.5N 111.9W 100 KT 115 MPH
72H 11/0000Z 14.4N 115.3W 115 KT 135 MPH
96H 12/0000Z 15.1N 118.4W 110 KT 125 MPH
120H 13/0000Z 15.4N 121.8W 100 KT 115 MPH

Global models indicate that yet another tropical depression could form behind Emilia in the next week as a weak upward pulse of the MJO remains in place. A majority of the global models also reveal that this system may not get very strong due to high wind shear induced by upper-level outflow from Emilia. Just like Daniel and Emilia, this potential system is expected to move west-northwest parallel to the Mexican coastline and should not make landfall. Meanwhile, in the Atlantic, none of the models are showing any tropical development over the next 10 days as the basin remains in a downward pulse of the MJO pulse. Thereafter, it is possible that a weak upward pulse could enter the East Atlantic, and we may need to watch that region for potential development by the end of the month.


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4. WeatherNerdPR
4:02 AM GMT on July 08, 2012
"Daniel has almost certainly peaked in intensity at this time."

Daniel wants to prove you wrong. He's strengthening again.
Member Since: July 7, 2010 Posts: 0 Comments: 5726
3. PedleyCA
3:54 AM GMT on July 08, 2012
Nice Blog. Well Done.
Member Since: February 29, 2012 Posts: 0 Comments: 8459
2. Civicane49
3:52 AM GMT on July 08, 2012
Thanks for the update!
Member Since: July 21, 2011 Posts: 83 Comments: 7167
1. nigel20
3:48 AM GMT on July 08, 2012
It's getting pretty active in the E pacific...thanks for the update, TA!
Member Since: November 6, 2010 Posts: 14 Comments: 9410

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Small town USA guy. Politics nerd. Soccer fan. Interested in eyewalls, deformation zones, and hook echos.

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