TS Katia | peak 60mph 998 mb | fish and ships | done

[StretchCT]

Starting this one to a TD/TS is eminent.  

Yesterday there was support for it, so now I'd be very surprised if they didn't upgrade it at the 11am 

 

Edited September 5, 2023 by StretchCT

[StretchCT]

Not a lot going for this one.  Dry air west/NW of it and shear in it's immediate path. Though the shear is from the SW, which could help it for a bit. 

Edited September 1, 2023 by StretchCT

[StretchCT]

TD 12 is official at the 11am advisory.  It is forecast to be named. There is 28c water in the area so it should strengthen before it reaches colder water as it heads N.  It also faces shear as mentioned earlier.  No threat to land, just fish and ships. 

 

 

Spoiler

WTNT44 KNHC 011448
TCDAT4

Tropical Depression Twelve Discussion Number   1
NWS National Hurricane Center Miami FL       AL122023
200 PM CVT Fri Sep 01 2023

The area of low pressure over the far eastern Atlantic to the 
northwest of the Cabo Verde Islands has developed a well-defined 
surface circulation with sufficiently organized deep convection to 
be classified as a tropical cyclone.  Dvorak classifications from 
TAFB and SAB are a consensus T2.5, but since the convection is 
loosely organized around the center, the initial intensity is 
started at 30 kt.

Sea surface temperatures of 27-28 degrees Celsius and low vertical 
shear during the next day or so should allow the depression to 
strengthen to a tropical storm later today or on Saturday.  However, 
the cyclone will be reaching marginally warm waters in 24-48 hours, 
and southerly shear is forecast to increase at about that same time. 
 The NHC forecast therefore shows weakening beginning in 48 hours, 
and the system is likely to degenerate into a remnant low by 60 
hours due to a loss of organized deep convection.  The remnant low 
is shown dissipating by day 4, following the majority of the global 
model fields.

The depression is moving toward the north-northwest (340 degrees) at 
7 kt between a mid-level ridge over western Africa and a mid- to 
upper-level low located over the eastern Atlantic.  The steering 
environment changes little during the next couple of days, and the 
depression is therefore expected to move toward the north-northwest 
or northwest, at a slightly faster speed, through 48 hours.  After 
the cyclone becomes a shallower remnant low, lower-level flow is 
expected to turn the system toward the west-northwest until it 
dissipates.  The track guidance is tightly clustered for the next 4 
days, and the NHC track forecast is very close to the HCCA consensus 
aid.

FORECAST POSITIONS AND MAX WINDS

INIT  01/1500Z 19.6N  28.3W   30 KT  35 MPH
 12H  02/0000Z 21.0N  29.0W   35 KT  40 MPH
 24H  02/1200Z 22.8N  30.2W   35 KT  40 MPH
 36H  03/0000Z 24.3N  31.4W   35 KT  40 MPH
 48H  03/1200Z 25.5N  32.8W   30 KT  35 MPH
 60H  04/0000Z 26.0N  33.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  04/1200Z 26.4N  34.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  05/1200Z...DISSIPATED

$$
Forecaster Berg

[StretchCT]

Peaking

FORECAST POSITIONS AND MAX WINDS

INIT  02/1500Z 23.9N  29.7W   45 KT  50 MPH
 12H  03/0000Z 25.1N  30.8W   45 KT  50 MPH
 24H  03/1200Z 26.2N  32.1W   40 KT  45 MPH
 36H  04/0000Z 27.0N  33.5W   35 KT  40 MPH
 48H  04/1200Z 27.6N  34.7W   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  05/0000Z 28.5N  35.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  05/1200Z 29.1N  36.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  06/1200Z...DISSIPATED

$$
Forecaster Blake

[1816]

I love this thread title

[StretchCT]

Overachieving storm, imagine that

[StretchCT]

3:00 AM GMT Mon Sep 4
Location: 27.1°N 33.4°W
Moving: WNW at 6 mph
Min pressure: 1007 mb
Max sustained: 35 mph

[StretchCT]

A little dramatic license from NHC

...KATIA HAS COME TO THE END... ...THIS IS THE LAST NHC ADVISORY...

9:00 PM GMT Mon Sep 4
Location: 28.0°N 34.4°W
Moving: NW at 2 mph
Min pressure: 1010 mb
Max sustained: 35 mph

Post-Tropical Cyclone Katia Discussion Number  14
NWS National Hurricane Center Miami FL       AL122023
900 PM GMT Mon Sep 04 2023

The convection clock has run out on Katia with no organized 
thunderstorm activity for most of the day.  No additional organized 
convection is expected either due to very dry air aloft and 
continued shear. Thus, the system is declared post-tropical, and 
this is the last NHC advisory. The winds are set to 30 kt in 
accordance with an earlier scatterometer pass.

Katia isn't moving much now, and it is forecast to drift in a small 
clockwise loop over the next day or two within the subtropical 
ridge.  The remnants of the system should move a bit faster 
southward on Wednesday, gradually weakening due to the unfavorable 
environment, and open up into a trough within 3 days.

[StretchCT]

Remnants of Katia in front of the next system to form today.