Tropical weather analysis - July 6, 2012

By: KoritheMan , 4:25 AM GMT on July 07, 2012

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Daniel finally becomes a hurricane. Satellite images show a large and increasingly organized hurricane. As of the latest NHC advisory, the following was posted:

Wind: 75 mph, with higher gusts
Location: 14.5°N 117.1°W
Movement: W at 12 mph
Pressure: 988 mb
Category: 1 (Saffir-Simpson Hurricane Scale)

A faint eye tried to appear on geostationary satellite images a few hours ago, but has since been obscured by convection.

Figure 1. Latest infrared satellite image of Hurricane Daniel. Image credit: NOAA

Sea surface temperature analyses indicate that the hurricane does not have much time to strengthen, as Daniel is sitting underneath water temperatures right at 27C. Upper tropospheric shear remains light, and a continuation of this general trend is expected. The light shear conditions aren't expected to be enough to keep the cyclone from weakening, and the usual negatives -- cooling SSTs and their attendant dry airmass -- are expected to deliver the coup de grace to the hurricane. Daniel is expected to dissipate by the end of the forecast period. The hurricane still does not pose a threat to Hawaii, although it may pass about 150 miles south of the Big Island on Friday as a remnant area of low pressure. If so, it would likely only enhance local shower activity, and perhaps deliver some gusty winds. My intensity forecast mirrors that of the National Hurricane Center except at day five, when I am forecasting a 25 kt storm as opposed to a 30 kt one. This is out of respect for the ginormous shear wall I see depicted in the GFS.

Daniel is still forecast to gain latitude, but its westward motion as a whole is not expected to come to an abrupt halt. The global models remain in good agreement with this, and my forecast track continues to closely follow that of the National Hurricane Center for lack of a reason to adjust it. On a side note, I just love when a tropical cyclone is embedded within a large-scale pattern that is actually easy to predict. Saves me a headache or two.

5-day intensity forecast

INITIAL 0300Z 07/07 65 KT 75 MPH
12 hour 1200Z 07/07 70 KT 80 MPH
24 hour 0000Z 07/08 70 KT 80 MPH
36 hour 1200Z 07/08 65 KT 75 MPH
48 hour 0000Z 07/09 55 KT 65 MPH
72 hour 0000Z 07/10 40 KT 45 MPH
96 hour 0000Z 07/11 30 KT 35 MPH
120 hour 0000Z 07/12 25 KT 30 MPH...POST-TROP/REMNANT LOW

5-day track forecast

Figure 2. My 5-day forecast track for Daniel.

Invest 97E

The tropical disturbance south of the Gulf of Tehuantepec that has been under surveillance for the last several days was designated an invest today ("97E"). This low continues to organize, and could become a tropical depression over the next day or two. A small burst of convection has recently formed near the estimated low-level center, although there might be some weak easterly shear over the area.

Figure 3. Latest infrared satellite image of Invest 97E. Image credit: NOAA

Satellite and scatterometer data indicate a closed circulation. The depiction of this circulation on satellite images was not particularly impressive, certainly less so than the ASCAT data would suggest. That little trifle notwithstanding, environmental conditions appear conducive for additional development. I see little reason why 97E will not become our next hurricane.

As for track, global and dynamical model guidance suggests that the synoptic pattern will be fairly similar to what big brother Daniel is experiencing. However, the mid-level flow seems to be more southerly as the system approaches 140W this time next week, which could allow for a more northward motion than Daniel is expected to exhibit at that longitude. While long-range prognostications are riddled with uncertainty, as Debby so kindly showed us, I am concerned about a long-range threat to the Big Island.

Probability of development within 48 hours: 60%


Most of the global models anticipate the development of a third tropical cyclone behind 97E/Emilia in about seven days. This system presumably comes in response to the tropical wave moving across the central Atlantic. It is decidedly too early to predict exactly where this system will go.

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3. LakeWorthFinn
11:25 PM GMT on July 07, 2012
Have a great weekend Kori!
Member Since: October 6, 2005 Posts: 67 Comments: 7395
2. GeorgiaStormz
11:07 AM GMT on July 07, 2012

did you see the CMC and UKMET are now developing the bahamas wave?

i still say it wont happen
Member Since: February 11, 2012 Posts: 0 Comments: 9738
1. Civicane49
4:37 AM GMT on July 07, 2012
Thanks Kori. I will keep an eye on both Daniel and 97E.
Member Since: July 21, 2011 Posts: 83 Comments: 7167

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About KoritheMan

I'm just a 23 year old with an ardent passion for weather. I first became aware of this interest after Tropical Storm Isidore struck my area in 2002.