10-16-2014, 11:06 AM
3:00 pm Ana update
After a brief period of convection firing over the center of circulation, it is once again displaced to the east side. Dry air is shown surrounding Ana, as well as being wrapped into her circulation.
The feathery clouds that radiate from Ana on the north, east and south sides is outflow, or exhaust from the storm's engine. The lack of outflow on the southwest and west sides is due to shear. The dry air and and shear are getting in the way of strengthening.
The latest run of the SHIPS intensity model shows shear currently at 8kts and decreasing to 3kts over the next 18 hours. After that, and as Ana makes her closest approach to the Big Island, shear is forecast to increase to 17kts. That kind of shear would be a problem for a weak system like this.
With shear forecast to drop to near zero and the evening bringing diurnal maximum for convection, there is certainly the opportunity for some intensification tonight.
The latest GFS model run just came out. It forecasts the center of circulation to be 2 degrees west of our island when it passes by. That's around 130 miles. Which works just fine for me
We're down in Hawaiian Beaches and we just started to hear early rollers come ashore a couple of hours ago. Pohoiki should be quite large all day tomorrow, but especially in the late afternoon. Northeast facing shores, and Hilo, look to escape the worst of the high surf. Surf should be larger as you head towards South Point. Wind should also be higher on that end of the island.
Although Ana is not a large tropical system, her circulation is much larger than our island. She will be bringing up large amounts of moisture over the entire island. The south facing slopes will be hardest hit.
Looks like lots of good news, but we've still got 36 hours until she's north of us, so stay informed in case her path and/or intensity changes between now and then.
I'll do another update this evening or sooner if conditions warrant.
http://harrysserver.com/x.png <- this is a satellite image that shows the center of circulation, shear, and dry air.
After a brief period of convection firing over the center of circulation, it is once again displaced to the east side. Dry air is shown surrounding Ana, as well as being wrapped into her circulation.
The feathery clouds that radiate from Ana on the north, east and south sides is outflow, or exhaust from the storm's engine. The lack of outflow on the southwest and west sides is due to shear. The dry air and and shear are getting in the way of strengthening.
The latest run of the SHIPS intensity model shows shear currently at 8kts and decreasing to 3kts over the next 18 hours. After that, and as Ana makes her closest approach to the Big Island, shear is forecast to increase to 17kts. That kind of shear would be a problem for a weak system like this.
With shear forecast to drop to near zero and the evening bringing diurnal maximum for convection, there is certainly the opportunity for some intensification tonight.
The latest GFS model run just came out. It forecasts the center of circulation to be 2 degrees west of our island when it passes by. That's around 130 miles. Which works just fine for me
We're down in Hawaiian Beaches and we just started to hear early rollers come ashore a couple of hours ago. Pohoiki should be quite large all day tomorrow, but especially in the late afternoon. Northeast facing shores, and Hilo, look to escape the worst of the high surf. Surf should be larger as you head towards South Point. Wind should also be higher on that end of the island.
Although Ana is not a large tropical system, her circulation is much larger than our island. She will be bringing up large amounts of moisture over the entire island. The south facing slopes will be hardest hit.
Looks like lots of good news, but we've still got 36 hours until she's north of us, so stay informed in case her path and/or intensity changes between now and then.
I'll do another update this evening or sooner if conditions warrant.
http://harrysserver.com/x.png <- this is a satellite image that shows the center of circulation, shear, and dry air.
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