• Member Statistics

    16,051
    Total Members
    7,904
    Most Online
    elYeti
    Newest Member
    elYeti
    Joined
WxWatcher007

Major Hurricane Laura

Recommended Posts

Just now, dan11295 said:

Lake Charles is a very bad position. Surge through the Lake plus likely the NE eye wall. The western eye wall is looking very vigorous as well. Hopefully that stays east of Port Arthur.

It should but Port Arthur is in for a good lashing. But much less surge affect than if this went 20 miles or so west. Lake Charles though.... :yikes:

Share this post


Link to post
Share on other sites

They finally released a dropsonde in the NE eyewall... 142 kt surface winds!  There's all you need for cat 5 status... confirms the last dropsonde from the previous aircraft as well. 

  • Like 1

Share this post


Link to post
Share on other sites
5 minutes ago, brianc33710 said:

There are tornado warnings all along the north border of the EWWs too. 

Yeah, the multiple tornado warnings are for "bands of severe storms capable of producing tornadoes".  This is in addition to the Extreme Wind Warning in effect associated with the northern eyewall of Laura.  This is insane.

  • Like 1

Share this post


Link to post
Share on other sites
Just now, brianc33710 said:

So far Lake Charles has the highest winds & lowest pressure of the obv stations I've seen, 29.50", winds 40 gusts to 58. I know that's all getting ready to change though. 

Another 45mb to go in the next 3 hrs, should be fun.

  • Weenie 1

Share this post


Link to post
Share on other sites

not that i'm complaining about the NWS doing what they're supposed to do but what even is a tornado in the context of the storm, this close to the core.  these are just tornado warnings on top of extreme wind warnings, probably no one is going to be able to tell if there's a tornado coming or if they're even in one.  low clouds, no visibility.  could these cells drop F3 damage that's actually meaningful relative to the overall hurricane?

  • Thanks 1

Share this post


Link to post
Share on other sites
Just now, PennyForYourThoughts said:

142 Kt dropsonde?  

Probably a caught in a gust. When it’s that much higher than SFMR it tends to be a gust.

Share this post


Link to post
Share on other sites

Probably a gust but impressive nonetheless 

 

Product: Air Force Temp Drop (Dropsonde) Message (UZNT13 KNHC)
Transmitted: 27th day of the month at 4:11Z
Agency: United States Air Force 
Aircraft: Lockheed WC-130J Hercules with reg. number AF96-5300 
Storm Number: 13
Storm Name: Laura (flight in the North Atlantic basin)
Mission Number: 25
Observation Number: 25 ( See all messages of this type for this mission. )

Part A...
 

Date: Near the closest hour of 4Z on the 27th day of the month
Highest Mandatory Level For Which Wind Was Reported: 700mb
Coordinates: 29.3N 93.0W
Location: 64 statute miles (104 km) to the S (169°) from Lake Charles, LA, USA.
Marsden Square: 082 ( About )
 
Surface and Standard Isobaric Surfaces
Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed
1000mb -421m (-1,381 ft) This level does not exist in this area of the storm above the surface level.
954mb (28.17 inHg) Surface (Sea Level) 25.6°C (78.1°F) 24.2°C (76°F) 95° (from the E) 142 knots (163 mph)
925mb 269m (883 ft) 24.0°C (75.2°F) 23.0°C (73°F) 100° (from the E) 157 knots (181 mph)
850mb 1,009m (3,310 ft) 21.4°C (70.5°F) 20.4°C (69°F) 140° (from the SE) 150 knots (173 mph)
700mb 2,683m (8,802 ft) 15.4°C (59.7°F) 14.6°C (58°F) 165° (from the SSE) 130 knots (150 mph)

Information About Radiosonde:
- Launch Time: 3:49Z
- About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction.

Remarks Section...
 
Dropsonde Location: Dropped in eyewall 45° (NE) from the eye center.

Highest altitude where wind was reported:
- Location: 29.33N 93.01W
- Time: 3:49:13Z

Lowest altitude where wind was reported:
- Location: 29.46N 93.14W
- Time: 3:53:56Z

Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding):
- Wind Direction: 105° (from the ESE)
- Wind Speed: 149 knots (171 mph)

Deep Layer Mean Wind (average wind over the depth of the sounding):
- Wind Direction: 135° (from the SE)
- Wind Speed: 134 knots (154 mph)
- Depth of Sounding: From 697mb to 953mb

Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding:
- Lowest 150m: 157 gpm - 7 gpm (515 geo. feet - 23 geo. feet)
- Wind Direction: 100° (from the E)
- Wind Speed: 151 knots (174 mph)

Sounding Software Version: AEV 30400
 

Part B: Data for Significant Levels...
 

Significant Temperature And Relative Humidity Levels
Level Air Temperature Dew Point
954mb (Surface) 25.6°C (78.1°F) 24.2°C (76°F)
850mb 21.4°C (70.5°F) 20.4°C (69°F)
700mb 15.4°C (59.7°F) 14.6°C (58°F)
 
Significant Wind Levels
Level Wind Direction Wind Speed
954mb (Surface) 95° (from the E) 142 knots (163 mph)
952mb 95° (from the E) 146 knots (168 mph)
951mb 95° (from the E) 141 knots (162 mph)
948mb 100° (from the E) 152 knots (175 mph)
940mb 105° (from the ESE) 153 knots (176 mph)
929mb 105° (from the ESE) 147 knots (169 mph)
923mb 100° (from the E) 158 knots (182 mph)
922mb 105° (from the ESE) 156 knots (180 mph)
919mb 110° (from the ESE) 148 knots (170 mph)
916mb 110° (from the ESE) 153 knots (176 mph)
911mb 110° (from the ESE) 153 knots (176 mph)
905mb 115° (from the ESE) 135 knots (155 mph)
888mb 120° (from the ESE) 165 knots (190 mph)
883mb 125° (from the SE) 160 knots (184 mph)
878mb 125° (from the SE) 164 knots (189 mph)
875mb 135° (from the SE) 145 knots (167 mph)
874mb 135° (from the SE) 142 knots (163 mph)
860mb 135° (from the SE) 155 knots (178 mph)
850mb 140° (from the SE) 150 knots (173 mph)
718mb 165° (from the SSE) 124 knots (143 mph)
697mb 165° (from the SSE) 137 knots (158 mph)
  • Like 1

Share this post


Link to post
Share on other sites
Just now, JasonOH said:

Probably a caught in a gust. When it’s that much higher than SFMR it tends to be a gust.

Awfully odd that the only two that have been dropped in the eastern section of the eye wall in the last 3 hours were "caught in gusts".  Could be a coincidence I  guess.

Share this post


Link to post
Share on other sites

Some weird gusts happen when the eyewall first starts interacting with land. Convective downdrafts weaken the storm in the long run but can probably increase winds locally.

Share this post


Link to post
Share on other sites

SFMR has been at least 15kt lower than the dropsonde value. Dropsondes measure instantaneous wind. Sustained winds are somewhere in the middle, probably ~130kt. NOAA drop 31 never reached the surface so it’s not too useful of a drop.

Share this post


Link to post
Share on other sites

A few final comments before I sleep...

1. Radar is looking better at the moment than it has looked in the last 1-2 hours. Very robust SW through N to E. The one concern, visible from both KLCH and KHGX radars is a more open portion of the spiral in the south. This appears to be filling in with the last couple radar images.This is likely what is leading to #2:

2. IR is showing some slight non-symmetry to the eyewall (not mesovorticies) that is generally indicative of a slightly weaker (but still major) hurricane.

3. Time is running out before landfall. Both recon (SFMWR and dropesondes) and radar is showing very powerful winds aloft, though mixing to the surface is still not fully occurring. Center pressures are falling again, indicating to me that the south issue with the eyewall may be closing up again. I am not sure there is enough time to strengthen, but it doesn't need much to meet the Category 5 threshold. I never discount any storms in the Gulf from doing crazy stuff since I've seen too many storms break every rule in the book before. My guess is at most 5-10 mph strengthening left before landfall, and likely little change, depending on how much winds at altitude are able to mix to the surface.

4. Landfall location often is slightly clockwise of the radar depicted path. This is due to drag on land vs open water. Doesn't always happen, but I've seen it enough to know that west of the hurricane is going to be "safer" than east of the hurricane from sudden last minute wobbles.


Laura_Aug27_1223est.gif

  • Like 1

Share this post


Link to post
Share on other sites
8 minutes ago, Will - Rutgers said:

not that i'm complaining about the NWS doing what they're supposed to do but what even is a tornado in the context of the storm, this close to the core.  these are just tornado warnings on top of extreme wind warnings, probably no one is going to be able to tell if there's a tornado coming or if they're even in one.  low clouds, no visibility.  could these cells drop F3 damage that's actually meaningful relative to the overall hurricane?

Sometimes they do. Many times there are actual tornadoes spun from the mesovortices within the eyewall. The tell-taling sign of these occurrences with long pathes of twisted trees and brush.  

  • Like 3

Share this post


Link to post
Share on other sites
11 minutes ago, Will - Rutgers said:

not that i'm complaining about the NWS doing what they're supposed to do but what even is a tornado in the context of the storm, this close to the core.  these are just tornado warnings on top of extreme wind warnings, probably no one is going to be able to tell if there's a tornado coming or if they're even in one.  low clouds, no visibility.  could these cells drop F3 damage that's actually meaningful relative to the overall hurricane?

Yeah, but if you're 40+ miles from the track and getting 75 mph winds or less, a tornado is a big deal...

  • Like 5

Share this post


Link to post
Share on other sites

Last pass through the NE quad from AF300 revealed 148kt FL winds-- ~170mph...

  • Like 1
  • Thanks 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.