Hurricane Debby

[NorthHillsWx]

Recon should provide a well timed pass here in a bit

[dbullsfan]

Maybe it’s a wobble but seems to be back in more of a NW direction as well, moving further from the coast. May only be an hour or two difference but the further west it goes the more time over water if/when it turns to the east.


.

[wthrmn654]

Wrong storm lol

[Jtm12180]

6 hours ago, WxWatcher007 said:

Yeah I’m not really sure what to think. The ensembles were split between the op and a more progressive track. 

That would be an absolutely catastrophic scenario for my neck of the woods…damn

[dan11295]

No question the potential for excessive rainfall over coastal GA/SC in particular is a major concern. Still not entirely clear Debby gets back over the Atlantic, which could impact level of flooding threat.

[weatherCCB]

First visible shows towers blowing near and around the center.

only a matter of time now

[WxWatcher007]

22 minutes ago, NorthHillsWx said:

Yep it’s just continued to look more and more impressive since I posted too. This looks like a very clear attempt at an eyewall

It tried very early this morning and failed, but it looks like it’s getting further along in this attempt. We’ll see if the radar look is reflected in a tighter RMW on the next recon pass. Still a fair amount of work to do on the western and southern side.

8 minutes ago, Jtm12180 said:

That would be an absolutely catastrophic scenario for my neck of the woods…damn

Hope your area ends up ok. The most consistent signal with this one continues to be rainfall.

5 minutes ago, dan11295 said:

No question the potential for excessive rainfall over coastal GA/SC in particular is a major concern. Still not entirely clear Debby gets back over the Atlantic, which could impact level of flooding threat.

It seems like the global models get it into the Atlantic even though the longer range tracks diverge. 
 

 

The Euro with a more progressive track (less prone to fully collapsing the steering pattern) keeps it offshore longer before a second landfall.

Not only is this important for the longer range track and intensity, but also coastal flooding. 

[wthrmn654]

Poor thing is only half looking hurricane. 

 

[WxWatcher007]

Sorry if I’m late but we have a D3 High risk for excessive rainfall in coastal SC and GA.

[BooneWX]

27 minutes ago, wthrmn654 said:

Poor thing is only half looking hurricane. 

 

Classic pre-boom shrimp look 

[hawkeye_wx]

The surface center is still weak and displaced to the wsw of the nice mid-level center we see on radar.

[TPAwx]

Starting up here in South Tampa.  Impressive rainfall rates in this band. 

[mob1]

Looks like recon flew into the relocated center now and extrapolated pressure is near 997 mb. 

[Windspeed]

Debby's lopsided look this morning is a little deceiving. Certainly, the eastern half of the larger circulation is more convectively active on satellite and radar; however, keep in mind that Debby's RMW is still relatively small despite the circulation being large with a large wind field. It's an organizing tropical cyclone, not a reorganizing former hurricane with a sloppy spread out RMW. As pressures begin to fall, it should tighten rather significantly. The core also now has multiple CBs rotating around that should aid in pressure falls and an increase in gradient. 24 hours remaining over very hot SSTs is plenty of time to reach hurricane intensity, and I am confident Debby will become a Category 1 prior to landfall along the Big Bend of Florida. Hopefully, there isn't enough time for RI to begin, but unfortunately, it can't be ruled out. A category 2 is quite possible here, and certainly any higher category potential made worse in that Debby will be undergoing intensification through landfall versus being a TC that is weakening.

[dbullsfan]

Starting up here in South Tampa.  Impressive rainfall rates in this band. 

Haven’t seen a drop here all morning, storm just too far west. I’m sure we will get a few bands or light rain but this is pretty much a northern Florida and up event. Really surprised Reed Timmer came to Tampa opposed to further up the coast


.

[BooneWX]

High winds and surge or not, Debby is already going to be one for the record books across the southeast. SC and Georgia - likely portions of NC as well, are going to see historic levels of flooding. This storm is looking like it’ll be a less sexy version of Hurricane Floyd. 

[Prospero]

54 mph gust at Egmont Channel:

[Ed, snow and hurricane fan]

USAFR flight suggests the center is still elliptical N to S (LLC and MLC not quite aligned.  I do see on radar (using Werathernerds site) that the center is making attempts at an eyewall, not quite getting there.  If the center does tighten up it should have more than a day of 30* + water to strengthen.

[TradeWinds]

13 minutes ago, dbullsfan said:

Haven’t seen a drop here all morning, storm just too far west. I’m sure we will get a few bands or light rain but this is pretty much a northern Florida and up event. Really surprised Reed Timmer came to Tampa opposed to further up the coast


.

You'll see decent squalls especially as it lifts north. Areas of central and north central peninsula probably will see their worst conditions Monday instead of today as it gets a more easterly movement and the plume drags with it.  

[wthrmn654]

 

 

[wthrmn654]

Recon analysis: 

 

[Windspeed]

USAFR flight suggests the center is still elliptical N to S (LLC and MLC not quite aligned.  I do see on radar (using Werathernerds site) that the center is making attempts at an eyewall, not quite getting there.  If the center does tighten up it should have more than a day of 30* + water to strengthen.

Downshear LLC reformation was occurring while reconnaissance was sampling the vortex. The LLC is now currently aligned, at least temporarily. We'll just have to see if the improving structure holds. If it does hold, intensification should be underway. Webb and Hazelton both recently made posts about this evolution of the vortex. It's also not uncommon in slightly sheared systems that are moving in a vector of the upper-level flow. Debby is a well-ventilated system even if there is shear to contend with, and there is net gain within the environment to support intensification (i.e. divergence aloft versus vortex tilt). We've seen this too often with northward moving systems in the GOM. The hope is that the presence of dry air in the western circulation in the mid-levels might get advected into the core circulation. But we're not dealing with strong shear either. Debby could close off and protect its core if these intense CBs keep wrapping it.

Here's a few posts about the vort evolution mentioned above.

[yoda]

Tropical Storm Debby Advisory Number   9
NWS National Hurricane Center Miami FL       AL042024
1100 AM EDT Sun Aug 04 2024

...DEBBY LIKELY TO STRENGTHEN RAPIDLY BEFORE LANDFALL IN THE
FLORIDA BIG BEND REGION...
...MAJOR FLOOD THREAT LOOMS OVER THE SOUTHEASTERN UNITED STATES...


SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...27.0N 84.3W
ABOUT 130 MI...210 KM WSW OF TAMPA FLORIDA
ABOUT 160 MI...260 KM SSW OF CEDAR KEY FLORIDA
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...992 MB...29.30 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

A Storm Surge Warning has been issued from the middle of Longboat
Key to Aripeka, Florida including Tampa Bay.

The Tropical Storm Warning for the Florida Keys east of the Dry
Tortugas is discontinued.

The Tropical Storm Watch for the Florida Keys north of the Seven
Mile Bridge to the Channel 5 Bridge is discontinued.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for...
* Florida coast from the middle of Longboat Key northward to Indian
Pass including Tampa Bay

A Storm Surge Watch is in effect for...
* Florida coast from Bonita Beach northward to the middle of
Longboat Key, including Charlotte Harbor
* Georgia and South Carolina coast from the Mouth of the St. Mary's
River to South Santee River South Carolina

A Hurricane Warning is in effect for...
* Florida coast from the Suwannee River to the Ochlockonee River

A Hurricane Watch is in effect for...
* Florida coast west of the Ochlockonee River to Indian Pass
* Florida coast south of the Suwannee River to Yankeetown

A Tropical Storm Warning is in effect for...
* Dry Tortugas
* Florida coast south of the Suwannee River to East Cape Sable
* Florida coast west of the Ochlockonee River to Indian Pass

A Tropical Storm Watch is in effect for...
* Florida coast west of Indian Pass to Mexico Beach
* Georgia and South Carolina coast from the Mouth of the St. Mary's
River to South Santee River South Carolina

A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area.  A warning is typically issued 36
hours before the anticipated first occurrence of
tropical-storm-force winds, conditions that make outside
preparations difficult or dangerous.  Preparations to protect life
and property should be rushed to completion.

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within 36 hours.

A Hurricane Watch means that hurricane conditions are possible
within the watch area. A watch is typically issued 48 hours before
the anticipated first occurrence of tropical-storm-force winds,
conditions that make outside preparations difficult or dangerous.

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

A Storm Surge Warning means there is a danger of life-threatening
inundation, from rising water moving inland from the coastline,
during the next 36 hours in the indicated locations. For a
depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
hurricanes.gov.

This is a life-threatening situation.  Persons located within these
areas should take all necessary actions to protect life and property
from rising water and the potential for other dangerous conditions.
Promptly follow evacuation and other instructions from local
officials.

A Storm Surge Watch means there is a possibility of life-
threatening inundation, from rising water moving inland from the
coastline, in the indicated locations during the next 48 hours.
For a depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
hurricanes.gov.

Interests elsewhere in Florida and the southeastern coast of the
United States should monitor the progress of this system.
Additional watches and warnings will likely be required later today.

For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.

[yoda]

Tropical Storm Debby Discussion Number   9
NWS National Hurricane Center Miami FL       AL042024
1100 AM EDT Sun Aug 04 2024

Hurricane Hunter aircraft observations indicate that Debby
continues to intensify over the eastern Gulf of Mexico.  Satellite
imagery shows that the cloud pattern is becoming better developed
with increasing deep convection near the center of circulation, and
WSR-88D radar data indicate that an eyewall is beginning to form.
The current intensity estimate is estimated to be 55 kt based on a
significant drop in central pressure reported the aircraft. 

The cyclone has been turning gradually to the right and the initial 
motion is north-northwestward or 330/11 kt.  Over the next day or 
so, Debby should move through a weakness in the mid-level 
subtropical ridge over the southeastern United States and reach the 
northeast Gulf of Mexico coast in the Florida Big Bend region on 
Monday.  After the system makes landfall, the steering currents are 
likely to weaken as a trough over the northeastern U.S. moves 
eastward from the area, which should result in a decrease in forward 
speed.  There is significant uncertainty in the track of Debby in 
the 2-5 day time frame.  Much of the track guidance keeps the center 
over the southeastern U.S. for the next several days as a ridge 
builds in over the Carolinas.  The official track forecast is 
similar to the previous one and close to the HFIP corrected 
consensus prediction.  This keeps the slow-moving center near the 
Georgia and South Carolina coast in the 3 to 5 day time-frame. 

Debby will be moving over very warm waters and in a low-vertical 
shear environment prior to landfall.  Therefore significant 
strengthening is likely through tonight, especially if the cyclone 
forms a well-defined inner core The official forecast is near the 
high side of the objective guidance and calls for the system to 
become a hurricane within 12 hours.  The cyclone will weaken after 
it moves inland, but since the system will not be far from the 
coastline for the next few days, it is not predicted to fall below 
tropical storm strength through 72 hours.

Key Messages:

1. Heavy rainfall will likely result in considerable flooding
impacts from the Florida Big Bend region through southeast GA and
the Coastal Plain of the Carolinas through Friday. Potentially
historic heavy rainfall across southeast Georgia and South Carolina
through Friday morning may result in areas of catastrophic 
flooding. Significant river flooding is also expected. 

2. There is a danger of life-threatening storm surge along portions
of the Gulf Coast of Florida, with 6 to 10 feet of inundation above
ground level expected somewhere between Ochlockonee River and
Suwannee River on Monday. Residents in the Storm Surge Warning area
should follow any advice given by local officials.

3.  Hurricane conditions are expected Monday along portions of the 
Florida Big Bend region where a Hurricane Warning is in effect, with 
tropical storm conditions beginning this evening. Tropical storm 
conditions are expected through Monday farther south within the 
Tropical Storm Warning along Florida's west coast, including the 
Tampa Bay area.

4. Impacts from storm surge and strong winds are possible along the
southeast coast from Georgia to North Carolina through the middle of
the week, and storm surge watches and tropical storm watches have
been issued for portions of these areas. Additional watches and
warnings will likely be required later today.


FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 27.0N  84.3W   55 KT  65 MPH
 12H  05/0000Z 28.3N  84.5W   65 KT  75 MPH
 24H  05/1200Z 29.9N  84.1W   80 KT  90 MPH
 36H  06/0000Z 30.9N  83.4W   60 KT  70 MPH...INLAND
 48H  06/1200Z 31.6N  82.5W   40 KT  45 MPH...INLAND
 60H  07/0000Z 31.9N  81.5W   35 KT  40 MPH...INLAND
 72H  07/1200Z 32.2N  80.5W   45 KT  50 MPH...OVER WATER
 96H  08/1200Z 33.5N  79.5W   40 KT  45 MPH...INLAND
120H  09/1200Z 35.5N  78.0W   30 KT  35 MPH...INLAND

$$
Forecaster Pasch

[Windspeed]

I completely missed there was a 993 mb reading on that last splashdown.

[southmdwatcher]

There are some healthy circulations with CC drops in the band approaching Tampa area.

[WxWatcher007]

 

[Jebman]

2 hours ago, WxWatcher007 said:

It tried very early this morning and failed, but it looks like it’s getting further along in this attempt. We’ll see if the radar look is reflected in a tighter RMW on the next recon pass. Still a fair amount of work to do on the western and southern side.

Hope your area ends up ok. The most consistent signal with this one continues to be rainfall.

It seems like the global models get it into the Atlantic even though the longer range tracks diverge. 
 

 

The Euro with a more progressive track (less prone to fully collapsing the steering pattern) keeps it offshore longer before a second landfall.

Not only is this important for the longer range track and intensity, but also coastal flooding. 

That's ridiculous, 20 to 30 inches of rain potentially. 

[TPAwx]

12z GFS op slightly east for landfall Mon AM

[dbullsfan]

8 minutes ago, TPAwx said:

12z GFS op slightly east for landfall Mon AM

Are you getting anything yet? Radar looking like some bands might start coming through shortly but it has been looking like that for a couple hours now and still waiting on first sign of rain. Even getting some blue skies popping through the breaks in clouds. Maybe its a dome over my area but just seems to break apart before it gets here each time.