• Member Statistics

    16,055
    Total Members
    7,904
    Most Online
    LostInSomers
    Newest Member
    LostInSomers
    Joined
WxWatcher007

Hurricane Sally

Recommended Posts

Latest VDM

 

Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 14th day of the month at 14:39Z
Agency: United States Air Force
Aircraft: Lockheed WC-130J Hercules with reg. number AF98-5308
Storm Number & Year: 19 in 2020
Storm Name: Sally (flight in the North Atlantic basin)
Mission Number: 6
Observation Number: 08 ( See all messages of this type for this mission. )

A. Time of Center Fix: 14th day of the month at 13:37:30Z
B. Center Fix Coordinates: 28.37N 86.83W
B. Center Fix Location: 143 statute miles (231 km) to the SSW (209°) from Panama City, FL, USA.
C. Minimum Height at Standard Level: 1,412m (4,633ft) at 850mb
D. Minimum Sea Level Pressure: 993mb (29.33 inHg)
E. Dropsonde Surface Wind at Center: From 295° at 20kts (From the WNW at 23mph)
F. Eye Character: Open in the northwest
G. Eye Shape & Diameter: Circular with a diameter of 12 nautical miles (14 statute miles)
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 42kts (48.3mph)
I. Location & Time of the Estimated Maximum Surface Wind Inbound: 37 nautical miles (43 statute miles) to the NW (306°) of center fix at 13:24:00Z
J. Maximum Flight Level Wind Inbound: From 79° at 50kts (From between the ENE and E at 57.5mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 68 nautical miles (78 statute miles) to the NNW (332°) of center fix at 13:13:00Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 18kts (20.7mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 23 nautical miles (26 statute miles) to the SW (232°) of center fix at 13:46:30Z
N. Maximum Flight Level Wind Outbound: From 301° at 19kts (From the WNW at 21.9mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 36 nautical miles (41 statute miles) to the SW (229°) of center fix at 13:50:30Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 17°C (63°F) at a pressure alt. of 1,516m (4,974ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 23°C (73°F) at a pressure alt. of 1,518m (4,980ft)
R. Dewpoint Temp (collected at same location as temp inside eye): 19°C (66°F)
R. Sea Surface Temp (collected at same location as temp inside eye): Not Available
S. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
S. Fix Level: 850mb
T. Navigational Fix Accuracy: 0.02 nautical miles
T. Meteorological Accuracy: 4 nautical miles

Remarks Section:
 

Maximum Flight Level Wind: 54kts (~ 62.1mph) which was observed 104 nautical miles (120 statute miles) to the NE (50°) from the flight level center at 12:37:00Z
  • Like 1

Share this post


Link to post
Share on other sites
23 minutes ago, Orangeburgwx said:

18,200 feet09a49b04595602c5ae7540ef2214301a.jpg3dd5fca1ec316efe082d6432f26a984b.jpg

Sent from my LML212VL using Tapatalk
 

I would caution taking samples from the range folding, as well as single pixels here or there that have no temporal continuity. It is not very representative of reality.

  • Like 2

Share this post


Link to post
Share on other sites

Excellent brief but informative thread about Sally by an expert atmospheric scientist who specializes in vortex evolution and center reformations in tropical cyclones:

Interesting comment as well:

Of note the decrease in the flash count after the peak is not necessarily a weakening sign, and it is due to the vortex alignment. While I hate to say this, further intensification is quite expected based on the current situation. Please stay safe!


  • Like 5

Share this post


Link to post
Share on other sites

That is one hell of a gravity wave that propagates out from the CDO beginning at 11:30Z and is still in progress as of 14:50Z. It's almost acting like a shock wave. You can see the density changes ahead of the wave on the southwest flank causing cloud clearing on the leading edge. This may also be causing the illusion that the outflow is stronger on the southwest flank than it really is. It looks like the bulk of the cirrus expansion in this quadrant is the outward push of the wave. Either way Sally looks pretty impressive right now relative to what it evolved from 12 hours ago.

Share this post


Link to post
Share on other sites
ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM

Tropical Storm Sally Discussion Number  12
NWS National Hurricane Center Miami FL       AL192020
1000 AM CDT Mon Sep 14 2020

An intense burst of deep convection with cloud tops colder than -80
degrees Celsius has developed over and the to east of the center
this morning. A recent fix from an Air Force Reserve Hurricane 
Hunter aircraft indicates that the center has reformed to the 
east of the previous estimated location, beneath the burst of 
deep convection.  NWS WSR-88D radar imagery shows an increase in 
banding around the eastern and southeastern portion of new center 
found by the aircraft and it appears that an eye is in its formative 
stage. The aircraft has reported believable SFMR winds of 55 kt, and 
that is the basis for the initial intensity.  The most recent 
minimum pressure estimated from the aircraft data is 991 mb, down 
several millibars from the first fix on this flight. 

Sally is located within a conducive environment of low wind shear, 
warm waters, and a moist atmosphere.  These conditions are likely to 
lead to steady strengthening over the next 24 hours or so.  With the 
recent increase in organization of the inner core, there is more 
confidence that Sally will strengthen to a hurricane later today or 
tonight. Additional strengthening is possible on Tuesday while the 
storm moves slowly northwestward near the coast of southeast 
Louisiana.  Increasing westerly wind shear and land interaction will 
probably slow the intensification rate by late tomorrow.  The new 
NHC intensity forecast is similar to the previous advisory and is 
near the upper-end of the guidance envelope.  Since Sally is 
forecast to be moving very slowly around the time of landfall a 
slower rate of weakening is indicated since a large portion of the 
circulation will remain over water for some time.

Given the recent re-formation of the center, the initial motion is a 
somewhat uncertain west-northwestward at 5 kt.  Weak ridging over 
the southeastern United State should steer Sally slowly west- 
northwestward through tonight.  After that time, a northwestward to 
northward turn is anticipated but the exact timing and location of 
the turn remains uncertain.  The general trend in the guidance has 
been eastward for the past few cycles, and the NHC forecast has been 
nudged in that direction and lies between the GFS and ECMWF models 
but a little west of the various consensus aids.

Regardless of the exact forecast track and intensity of Sally,
the slow-moving storm is expected to cause a life-threatening storm
surge and freshwater flooding event.

KEY MESSAGES:

1. It is too early to determine where Sally's center will move
onshore given the uncertainty in the timing and location of Sally's
northward turn near the central Gulf Coast.  Users should not focus
on the details of the official forecast track, since NHC's average
forecast error at 48 hours is around 80 miles, and dangerous storm
surge, rainfall, and wind hazards will extend well away from the
center.

2. An extremely dangerous and life-threatening storm surge is
expected for areas outside the southeastern Louisiana Hurricane and
Storm Damage Risk Reduction System from Port Fourchon, Louisiana, to
the Alabama/Florida border, where a Storm Surge Warning is in
effect. Residents in these areas should follow any advice given by
local officials.

3. Hurricane conditions are expected tonight within the Hurricane 
Warning area in southeastern Louisiana and are expected by late 
Tuesday within the Hurricane Warning area along the Mississippi and 
Alabama coastline. Tropical storm conditions are likely to begin  
later today and this evening in these areas and preparations 
should be rushed to completion. 

4. Life-threatening flash flooding is likely, as well as widespread 
minor to isolated major flooding, on area rivers along and just 
inland of the Central Gulf Coast. Significant flash and urban 
flooding, as well as widespread minor to moderate river flooding is 
likely across Mississippi and Alabama through the middle of the 
week.  Flooding impacts are expected to spread farther across the 
Southeast through the week. Sally could continue to produce flash 
flooding across the Florida peninsula and prolong existing minor 
river flooding across west-central Florida through today. 

FORECAST POSITIONS AND MAX WINDS

INIT  14/1500Z 28.4N  86.9W   55 KT  65 MPH
 12H  15/0000Z 28.7N  88.0W   65 KT  75 MPH
 24H  15/1200Z 29.2N  88.8W   75 KT  85 MPH
 36H  16/0000Z 29.8N  89.1W   80 KT  90 MPH
 48H  16/1200Z 30.8N  88.7W   60 KT  70 MPH...INLAND
 60H  17/0000Z 31.8N  87.7W   30 KT  35 MPH...INLAND
 72H  17/1200Z 32.6N  86.5W   25 KT  30 MPH...INLAND
 96H  18/1200Z 33.1N  84.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  19/1200Z...DISSIPATED

$$
Forecaster Brown

NNNN

 

095754_5day_cone_no_line_and_wind.png

Share this post


Link to post
Share on other sites

Impressive convective burst but still struggling to solidify upshear convection. If that doesn’t occur, the current rate of strengthening will continue. I think landfall may trend to AL/MS border due to extremely slow speed and center reformation East and models are correcting in that direction. Slower it goes, less westward progress will be made before the ridge moves east allowing the northward turn 

  • Like 1

Share this post


Link to post
Share on other sites

This storm is so deep its getting caught in upper level southerly steering flow. Radar and satellite suggests its heading due north towards the coast. Maybe a chance track forecast totally busts and it goes due north and makes landfall tonight in like Alabama or even Pensacola?

  • Weenie 3

Share this post


Link to post
Share on other sites
Core is really getting going now. 

7aae82e718cd0d2f82fe33148d735686.png&key=4c2e994e99afc26c084d7844d85245fa879f691f710b846f046ea41468647cfe

The low-level feeders into the developing eyeband on the northern and eastern semicircle are what have my attention. That is a sign of the vortex stacking as the southern semicircle of the low level circulation and low level southwesterly jet is healthy. Dynamics are increasing and divergence over the core is very high right now. I'd imagine pressure falls will continue and even ramp up if this internal structure can persist.

Share this post


Link to post
Share on other sites
5 minutes ago, Superstorm93 said:

Core is really getting going now. 

7aae82e718cd0d2f82fe33148d735686.png

Storm has a cat 1 appearance on radar. Velocities seem to suggest a hurricane as well. Bet we see an update, if not I believe it will be classified as such at 2pm

Share this post


Link to post
Share on other sites
7 minutes ago, turtlehurricane said:

This storm is so deep its getting caught in upper level southerly steering flow. Radar and satellite suggests its heading due north towards the coast. Maybe a chance track forecast totally busts and it goes due north and makes landfall tonight in like Alabama or even Pensacola?

I was surprised the NHC didn't adjust much further east. This clearly will be closer to Alabama/FL.

  • Like 1

Share this post


Link to post
Share on other sites

Is consensus still that this won’t be a major by LF? It’s slow pace should keep it over warm water for at least 30+ hours 

Share this post


Link to post
Share on other sites

Last AF recon was cool, pretty much documented the LLC relocating back under the MLC, rotating around the S part of the broader circulation. Don't think I've seen recon missions that were in at the exact moment of this.    NOAA in there now to continue.  Perhaps we'll get to see a wobbling top stand up in real time.  

  • Like 1

Share this post


Link to post
Share on other sites
Last AF recon was cool, pretty much documented the LLC relocating back under the MLC, rotating around the S part of the broader circulation. Don't think I've seen recon missions that were in at the exact moment of this.    NOAA in there now to continue.  Perhaps we'll get to see a wobbling top stand up in real time.  
AF308 did a U turn and is heading back in

Sent from my LML212VL using Tapatalk

  • Thanks 1

Share this post


Link to post
Share on other sites

This is not a fun forecast for the NHC when it comes to New Orleans over to Biloxi & Mobile Bay. A slow moving/strengthening (soon to be) Hurricane.

Share this post


Link to post
Share on other sites

12z GFS is an extremely slow crawl into Mississippi with pressure in the low 970's between hour 36-42. Not sure if this run initialized with the correct center position.

We're going to see some absurd rainfall amounts

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.