Dr. Jeff Masters' WunderBlog

Category 5 Super Typhoon Megi hits the Philippines
Posted by: Dr. Jeff Masters, 1:23 PM GMT on October 18, 2010 +5
Super Typhoon Megi hit northern Luzon Island in the Philippines near 3:30 UTC this morning as a Category 5 Super Typhoon with sustained winds of 165 mph and a central pressure of 914 mb, as rated by the Navy Research Lab in Monterey. Megi is the strongest Category 5 tropical cyclone to make landfall in the world since August 21 2007, when Hurricane Dean hit Mexico's Yucatan Peninsula with sustained winds of 175 mph and central pressure of 905 mb. We were fortunate to get precise measurements of Megi's intensity yesterday morning thanks to the Hurricane Hunters, who were investigating the typhoon in support of the Interaction of Typhoon and Ocean Project (ITOP), which is studying how the ocean responds to typhoon growth and movement in the Western Pacific Ocean. A C-130 hurricane hunter aircraft penetrated into Megi at 10,000 feet, and found an extraordinarily intense storm. At 9:05am EDT on Sunday (13:09 UTC), the aircraft recorded a central pressure in Megi of 890 mb. This is a phenomenally low pressure, ranking Megi (unofficially) as the 16th strongest tropical cyclone in world history. Only two Atlantic hurricane have been more intense than Megi--Wilma (2005) at 882 mb, and Gilbert (1988) at 888 mb. As they penetrated Megi's eyewall, the Hurricane Hunters performed the standard practice of maintaining a constant "pressure altitude"--the altitude one would expect to find a 700 mb pressure at in an atmosphere at standard conditions. In order to maintain a constant pressure altitude of 10,000 feet, the aircraft was forced to descend 3,000 feet in altitude as it entered Megi's eye. The aircraft entered the eye at 7,000 feet, so the pressure in Megi's eye was what one would normally find at an altitude 3,000 feet higher in the atmosphere. The aircraft recorded a remarkable increase in temperature of 12°C (22°F) as it crossed from the eyewall into the warm eye of Megi. A 12°C rise in eye temperature is extraordinarily rare in a tropical cyclone. Equally noteworthy were Megi's winds. The Hurricane Hunters measured winds at flight level of 220 mph, which normally translates to a surface wind speed of 198 mph, using the standard 10% reduction. The SFMR surface wind measurement instrument recorded surface winds of 186 mph in regions where heavy rain was not contaminating the measurement, but found surface winds of 199 mph in one region of heavy rain. Now, this measurement is considered contaminated by rain, but at very high wind speeds, the contamination effect is less important than at lower hurricane wind speeds, and it is possible than Megi's surface winds reached sustained speeds of 200 mph. However, data from a dropsonde in the eyewall at the time supported giving Megi just 180 mph sustained winds. This is still a ridiculously strong wind, equivalent to a violent EF-4 tornado on the Enhanced Fujita Scale.


Figure 1. Visible satellite image of Megi taken by NASA's Terra satellite at 2:25 UTC October 18, 2010. Image credit: NASA.

Passage over Luzon Island has weakened Megi to a still-formidable Category 3 typhoon with 125 mph winds, and Megi is pounding the northern portion of the island with torrential rains. We don't have many cities in the Philippines along Megi's path that report weather conditions, so it is difficult to know how strong the storm is. Tuguegarao, to the north of where Megi's eyewall passed, bottomed out at 978 mb pressure, had top sustained winds of 27 mph, and picked up 3.23" of rain thus far from the storm. Megi's rains, which will likely accumulate to more than a foot along a wide swath of northern Luzon (Figure 2), will create dangerous mudslides and life-threatening flash floods. Once Megi crosses Luzon, the storm is expected to re-intensify and hit the Chinese coast between Hainan Island and Hong Kong as a major typhoon on Friday.


Figure 2. Rainfall forecast for the 24 hours ending at 8pm EDT October 18, 2010, based on satellite estimates of Megi's rainfall rate. Rainfall amounts in excess of 12 inches (red colors) were predicted along a wide swath of Luzon Island. Image credit: NOAA/NESDIS.

Caribbean disturbance 99L
Heavy thunderstorm activity has increased over the past day over the southwestern Caribbean off the coasts of Nicaragua and Honduras in association with a tropical disturbance (Invest 99L). Recent satellite imagery does show this disturbance has some rotation, and wind shear is a moderate 10 - 20 knots, which is low enough to allow some slow development. However, the disturbance is headed west-northwest at 5 - 10 mph, and most of the computer models predict the storm will move over Nicaragua on Tuesday, which would not give 99L enough time over water to develop into a tropical depression. NHC is giving 99L a 30% chance of developing into a tropical depression by Tuesday. The storm will bring very heavy rains of 3 - 6" to northern Honduras and northeast Nicaragua over the next two days.

Next update
I'll have an update Tuesday morning.

Jeff Masters
Categories: Hurricane
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651. GeoffreyWPB 1:21 PM GMT on October 19, 2010    
Member Since: September 10, 2007 Posts: 0 Comments: 9248
657. IKE 1:26 PM GMT on October 19, 2010    
AL, 99, 2010101912, , BEST, 0, 165N, 833W

This buoy is at 16.8N and 81.5W....buoy 42057...

5-day plot - Wind Direction Wind Direction (WDIR): ESE ( 110 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 9.7 kts
5-day plot - Wind Gust Wind Gust (GST): 13.6 kts
5-day plot - Wave Height Wave Height (WVHT): 3.0 ft
5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 6 sec
5-day plot - Average Period Average Period (APD): 4.6 sec
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.90 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): +0.06 in ( Rising )
5-day plot - Air Temperature Air Temperature (ATMP): 78.8 °F
5-day plot - Water Temperature Water Temperature (WTMP): 83.3 °F
5-day plot - Dew Point Dew Point (DEWP): 74.5 °F
5-day plot - Heat Index Heat Index (HEAT): 82.2 °F
Member Since: June 9, 2005 Posts: 23 Comments: 37070
658. robert88 1:26 PM GMT on October 19, 2010    
Shear is going to be destructive in the GOM for days to come. Even if 99L makes it into the GOM it gets beheaded like Paula did. Anything between 20 and 25N is doomed. Conditions have not been favorable in the GOM for the majority of the season and looks like it will continue to stay that way through November. Link
Member Since: May 22, 2010 Posts: 0 Comments: 877
660. surfmom 1:27 PM GMT on October 19, 2010    
Quoting stillwaiting:
...heard they caught a 4-5 footer that was about 2-3 months ago at big pass...no wet roads in your neckof the woods????,we've had light rain here near the village for the last hour or so...nothing heavy though,***fingers crossd the precip in gom makesit ashore***
Got a fine light mist - glorious to get some moisture - my fruit trees are singing!!! (but they are also begging for MORE - been a long spell between rains) did not hear about that shark catch -- thanks for the information (well sort of - ignorance is not bliss in this case)maybe if we both concentrate, we can get that rain to come on shore!!!! getting ready to run & I love RAINRUNNING - com ON R A I N!!!!!!!
Member Since: July 18, 2007 Posts: 30 Comments: 26538
662. mcluvincane 1:30 PM GMT on October 19, 2010    
Quoting robert88:
Shear is going to be destructive in the GOM for days to come. Even if 99L makes it into the GOM it gets beheaded like Paula did. Anything between 20 and 25N is doomed. Conditions have not been favorable in the GOM for the majority of the season and looks like it will continue to stay that way through November. Link


Not so bad in a weeks time. Shouldn't b a problem for it with a anti cyclone overhead
Member Since: June 2, 2010 Posts: 0 Comments: 1315
663. Orcasystems 1:30 PM GMT on October 19, 2010    
Member Since: October 1, 2007 Posts: 77 Comments: 26110
664. Dakster 1:30 PM GMT on October 19, 2010    
Stillwaiting - I hope you are able to keep your handle through next season to. (You will still be waiting...)
Member Since: March 10, 2006 Posts: 0 Comments: 5266
665. BLee2333 1:31 PM GMT on October 19, 2010    
Morning folks!

Been out for two weeks for surgery and I see very little has changed as far as the atmosphere of the blog goes!

Wish I could have been on board with Paula. I bet this place was hopping!!
Member Since: January 6, 2009 Posts: 0 Comments: 217
667. FSUCOOPman 1:33 PM GMT on October 19, 2010    
Quoting cat5hurricane:

Agreed. GOM is a death trap for anything even thinking about it.


towards the VERY end of that model run (last frame) it almost looks like some lower shear is trying to make it's way into the Gulf across Mexico...
Member Since: August 29, 2008 Posts: 0 Comments: 343
669. stormpetrol 1:33 PM GMT on October 19, 2010    
San Andres, CO (Airport)
Updated: 8:00 AM COT on October 19, 2010

27 °C
Scattered Clouds
Humidity: 84%
Dew Point: 24 °C
Wind: 7 km/h / 2.1 m/s from the West

Pressure: 1012 hPa (Rising)
Heat Index: 30 °C
Visibility: 10.0 kilometers
UV: 2 out of 16
Clouds:
Few 487 m
Scattered Clouds 6096 m
(Above Ground Level)
Elevation: 2 m
Member Since: April 29, 2007 Posts: 0 Comments: 6493
671. ShenValleyFlyFish 1:36 PM GMT on October 19, 2010    
Vietnam is a very wet place today.
Member Since: September 9, 2007 Posts: 36 Comments: 4684
673. stormpetrol 1:37 PM GMT on October 19, 2010    

Puerto Cabezas, NK (Airport)
Updated: 36 min 12 sec ago

23 °C
Scattered Clouds
Humidity: 94%
Dew Point: 22 °C
Wind: 7 km/h / 2.1 m/s from the WNW

Pressure: 1011 hPa (Falling)
Visibility: 8.0 kilometers
UV: 2 out of 16
Clouds:
Scattered Clouds 487 m
(Above Ground Level)
Elevation: 20 m
Member Since: April 29, 2007 Posts: 0 Comments: 6493
674. ShenValleyFlyFish 1:37 PM GMT on October 19, 2010    
BBC Typhoon Megi report.
Member Since: September 9, 2007 Posts: 36 Comments: 4684
675. robert88 1:40 PM GMT on October 19, 2010    
Quoting cat5hurricane:

Agreed. GOM is a death trap for anything even thinking about it.


I would of thought this season with such a strong La Nina in place the GOM would have some amazing conditions out there for the 4th quarter. It will be interesting to hear what the experts explanation might be on this over the off season.
Member Since: May 22, 2010 Posts: 0 Comments: 877
677. Neapolitan 1:50 PM GMT on October 19, 2010    
Member Since: November 8, 2009 Posts: 4 Comments: 11306

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About JeffMasters
Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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