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WxWatcher007

Hurricane Sally

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The radar presentation this morning is the best this storm has looked so far.  Essentially, the storm looks to have undergone an eye-wall replacement of sorts with the collapse of the once 4 mile wide eye that had drilled down with yesterdays insane convective blow up with a +- 25 mile wide eye that is nearly closed.  

Most models have long insisted that modest intensification would occur as the storm nears landfall, and with the friction effects common as storms near the coast, it would not be surprising at all to see the core tighten as it nears the coast.  Some modest strengthening along with the slow movement and rather large wind-field is trouble for Mobile Bay if the center landfalls near the Mississippi/Alabama border which is rather likely.  

The current stall is its biggest hurdle at this point. I suppose the fascination here lies in what condition Sally's core will be in by midnight regardless of any short-term intensity fluctuations. I'm just not sure it can maintain any stronger intensity long after any potential short-term strengthening at such a slow pace of motion, much less avoid another period of weakening prior to landfall. That's the question here. Can it maintain hurricane intensity into landfall, much less strengthen into landfall as late hour TC modeling suggest? We shall see. Meanwhile it continues to crawl.25491f209a87fa23d6259e9e9716b20c.gif&key=b7d4610c361965fbbc9af0fcbbeb5ad460f471f0217375d70e1e1867650ec793

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Are you talking about Teddy?
I think he's referring to Sally's circulation redeveloping off the SECONUS this weekend / early next week with a strong ridge overhead. It's in the mid-range so possible but who knows. Looks like the ECMWF wants to dig a positively tilted shortwave trough over the Eastern Seaboard. I'd imagine anything that might develop would get kicked out into the Maritimes.
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4 minutes ago, Windspeed said:

The current stall is its biggest hurdle at this point. I suppose the fascination here lies in what condition Sally's core will be in by midnight regardless of any short-term intensity fluctuations. I'm just not sure it can maintain any stronger intensity long after any potential short-term strengthening at such a slow pace if motion, much less avoid another period of weakening prior to landfall. That's the question here. Can it maintain hurricane intensity into landfall, much less strengthen into landfall as late hour TC modeling suggest? We shall see. Meanwhile it continues to crawl.25491f209a87fa23d6259e9e9716b20c.gif

Water temps still are running 81-83 at some of the buoy's I looked at north of the storm.  Not too shabby considering there has been tropical storm conditions over them for almost 24 hours.  But yep, no doubt, the slow movement will keep a lid on intensity.  I do doubt that absent some 15kts or better shear it weakens though.   

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I take a differing opinion and say I expect increased organization today. Most of the models have been showing today and lead up to landfall being the best time for an increase in intensity. How much is always up for debate. 

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Still sticking with a 70kt landfall. Calling card will be rain and surge. You can see that even though the overall organization of the eye structure has somewhat improved, echoes in the eyewall are not that strong. While there could be some ups and downs, I expect the overall trend to be downwards on approach. Still, a cat 1 crawling onto the shore will be plenty disruptive wind wise. We saw a similar situation with Florence in N.C. These two systems are not that dissimilar in terms of environment pre-landfall and impacts 

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Water temps still are running 81-83 at some of the buoy's I looked at north of the storm.  Not too shabby considering there has been tropical storm conditions over them for almost 24 hours.  But yep, no doubt, the slow movement will keep a lid on intensity.  I do doubt that absent some 15kts or better shear it weakens though.   

I'd consider those temperatures temporary. They were running 28-30°C (84-86°F) a mere 24 hours ago. Those SSTs between the mouth of the Mississippi River and the AL/FL coastal state line are going to continue dropping throughout the day though with such heavy rainfall training over the same locations mixing surface layers. I wouldn't be surprised to see 25-26C° surface buoy data by tonight. The upper tropospheric temperature profiles would not appear to be cold enough to maintain the kind of strong lapse rates to support a hurricane at that point. This isn't the upper eastern Atlantic basin where we can sometimes see cooler SSTs support strong lapse rates and lift due to a cooler upper-tropospheric regime. At any rate, we're going from a stall to merely a gradual N to NNE motion when Sally regains motion. We'll just have to wait and see what plays out.
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6 minutes ago, HKY_WX said:

I take a differing opinion and say I expect increased organization today. Most of the models have been showing today and lead up to landfall being the best time for an increase in intensity. How much is always up for debate. 

Might be fair. I was pretty down on it last night but recon and radar are both looking noticeably better. 

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4 minutes ago, the ghost of leroy said:

Might be fair. I was pretty down on it last night but recon and radar are both looking noticeably better. 

Though the pressure has fallen, SFMR and FL wind data supports a weaker storm still. Barely finding 65 kts. First pass but I see nothing to indicate strengthening. I think pressure falls may be related to a broadening circulation. Tropical storm force winds continue to expand. This will not help the surge situation 

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Pressure falling, better look on radar. so the HWRF forecast of about 967mb and close to cat 2 at landfall are not that far fetched IMO. Regardless still a pretty bad surge and a ton of rainfall. Some record flood stages already being forecast by the NWS.

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I think we’re going to see many areas east of the center easily exceed 24” of rain. The feeder band to the northeast has been barely moving for many hours and model guidance continues to poorly resolve this feature in terms of intensity vs real time radar....Pensacola to Panama City look like  potential jackpots...

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2 minutes ago, jbenedet said:

I think we’re going to see many areas east of the center easily exceed 24” of rain. The feeder band to the northeast has been barely moving for many hours and model guidance continues to poorly resolve this feature in terms of intensity vs real time radar....Pensacola to Panama City look like  potential jackpots...

Only question that remains to be seen is how easily these areas flood. Is it possible that since they're on the coast, a lot of the rainfall will run off into the ocean, as opposed to Florence and Harvey situation?

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26 minutes ago, NorthHillsWx said:

Though the pressure has fallen, SFMR and FL wind data supports a weaker storm still. Barely finding 65 kts. First pass but I see nothing to indicate strengthening. I think pressure falls may be related to a broadening circulation. Tropical storm force winds continue to expand. This will not help the surge situation 

I just mean pressure falls and a visibly better eye. It looks better than last night when I was headed to bed. I still don’t have high hopes for all the reasons I have been harping on. 

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44 minutes ago, NorthHillsWx said:

Still sticking with a 70kt landfall. Calling card will be rain and surge. You can see that even though the overall organization of the eye structure has somewhat improved, echoes in the eyewall are not that strong. While there could be some ups and downs, I expect the overall trend to be downwards on approach. Still, a cat 1 crawling onto the shore will be plenty disruptive wind wise. We saw a similar situation with Florence in N.C. These two systems are not that dissimilar in terms of environment pre-landfall and impacts 

Umm Florence was piling up water as a cat 4 and had a huge sustained wind field of hurricane force winds.. Not sure I'd compare the 2 in that way.

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3 minutes ago, Dunkman said:

Umm Florence was piling up water as a cat 4 and had a huge sustained wind field of hurricane force winds.. Not sure I'd compare the 2 in that way.

Florence was also east coast, deep shelf, much more difficult to sustain a surge. 

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Subtle, but not insignificant east trending in the mesoscale and even global models in the last couple runs.

Wouldn't surprise me to see a landfall closer to Pensacola than Mobile. 

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4 minutes ago, beanskip said:

Subtle, but not insignificant east trending in the mesoscale and even global models in the last couple runs.

Wouldn't surprise me to see a landfall closer to Pensacola than Mobile. 

Yeah or atleast increasing their surge threat.

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After having one of the best eye presentations this morning that Sally has ever had, it now is back to a really junky look. Doesn’t look like recon has found any hurricane-force SFMR this morning either... 

COC is filled in with convection and all sorts of precip with a notable dry slot on the western side.

Probably a tropical storm ATTM. Not to say it can’t restrengthen, but definitely has been on a weakening trend.

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1 hour ago, MJO812 said:

Are you talking about Teddy?

No, Ted is a goner. I mean a storm that will form in the  bahamas.

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Latest VDM. Noting to say that hasn't been said already. The core is better than it was late yesterday, but still struggling in the face of shear and some upwelling. 

 

Product: NOAA Vortex Message (URNT12 KWBC)
Transmitted: 15th day of the month at 15:44Z
Agency: National Oceanic and Atmospheric Administration (NOAA)
Aircraft: Lockheed WP-3D Orion (Reg. Num. N43RF)
Storm Number & Year: 19 in 2020
Storm Name: Sally (flight in the North Atlantic basin)
Mission Number: 11
Observation Number: 13 ( See all messages of this type for this mission. )

A. Time of Center Fix: 15th day of the month at 15:16:32Z
B. Center Fix Coordinates: 29.14N 88.16W
B. Center Fix Location: 103 statute miles (166 km) to the SSE (148°) from Gulfport, MS, USA.
C. Minimum Height at Standard Level: 2,971m (9,747ft) at 700mb
D. Minimum Sea Level Pressure: 983mb (29.03 inHg)
E. Dropsonde Surface Wind at Center: From 130° at 14kts (From the SE at 16mph)
F. Eye Character: Open in the southwest
G. Eye Shape & Diameter: Circular with a diameter of 30 nautical miles (35 statute miles)
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 55kts (63.3mph)
I. Location & Time of the Estimated Maximum Surface Wind Inbound: 15 nautical miles (17 statute miles) to the SE (137°) of center fix at 15:13:02Z
J. Maximum Flight Level Wind Inbound: From 228° at 61kts (From the SW at 70.2mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 28 nautical miles (32 statute miles) to the SE (139°) of center fix at 15:09:40Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 54kts (62.1mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 19 nautical miles (22 statute miles) to the NW (312°) of center fix at 15:21:11Z
N. Maximum Flight Level Wind Outbound: From 42° at 63kts (From the NE at 72.5mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 18 nautical miles (21 statute miles) to the NW (312°) of center fix at 15:21:09Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 14°C (57°F) at a pressure alt. of 3,064m (10,052ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 19°C (66°F) at a pressure alt. of 3,061m (10,043ft)
R. Dewpoint Temp (collected at same location as temp inside eye): 10°C (50°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: 700mb
T. Navigational Fix Accuracy: 0.01 nautical miles
T. Meteorological Accuracy: 1.5 nautical miles

Remarks Section:
 

Maximum Flight Level Wind: 71kts (~ 81.7mph) which was observed 27 nautical miles (31 statute miles) to the SW (225°) from the flight level center at 14:26:51Z

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34 minutes ago, Dunkman said:

Umm Florence was piling up water as a cat 4 and had a huge sustained wind field of hurricane force winds.. Not sure I'd compare the 2 in that way.

I meant the atmospheric conditions leading up to landfall, not the storms themselves. Both are experiencing moderate shear, intrusions of dry air, and collapsed steering currents over shelf waters. I’d expect similar difficulty in predicting landfall and a steady state/slightly weakening system. Surge in this case will be worse due to location 

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Radar showing the misaligned centers pretty well.  MLC is to the ESE of the LLC  They have an overlap in the middle kind of like a venn diagram.

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This was and will always be more of a hydro issue with surge probably secondary. The Gulf is already high with the building seas, so you figure any river or stream feeding into it, will be backed up a bit. Add on top of that, all that water. 

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4 minutes ago, Seminole said:

12Z HMON has COC of Sally in Mobile Bay 6Z Wed. 

 

Most models keep it moving though, 12z GFS brings it inland about 12z tomorrow

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