ATL: KARL - Post-Tropical - Discussion

[Hammy]

Both Gonzo and Miss Piggy are flying towards Karl.

Are these going to be a combination of surface/upper air data?

[Hammy]

Models are backing off significantly on intensity, I think the likelihood this gets any higher than Cat 1 has gone out the window with the shear forecast.

[cycloneye]

Both Gonzo and Miss Piggy are flying towards Karl.

Are these going to be a combination of surface/upper air data?

Yes.

[cycloneye]

[cycloneye]

[Alyono]

looks like a weak TD based upon the preliminary aircraft data

[cycloneye]

TROPICAL STORM KARL DISCUSSION NUMBER 26
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122016
ISSUED BY THE NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
500 PM AST TUE SEP 20 2016

Karl's center had lost some definition throughout the day, but deep
convection has redeveloped near the center late in the afternoon.
Dvorak Current Intensity estimates were lowered to 2.5 from TAFB and
2.0 from SAB, and the latest UW-CIMSS ADT estimate is T3.2. A NOAA
P-3 flight currently conducting a research mission into Karl has
not yet found tropical-storm-force winds, but it has not sampled
the entire circulation yet. The initial intensity is therefore held
at 35 kt pending additional data from the P-3. The minimum pressure
is lowered to 1005 mb based on dropsonde data from the NOAA G-IV
jet, which is also flying near Karl.

Little to no change is expected in the strength of Karl over the
next 24 hours as the influence of an upper low continues to shear
out the western side of the storm. The global models indicate that
the shear should relax in the next 24 to 36 hours allowing a slight
strengthening in that period. As Karl rounds the mid-level ridge
it will find itself in a more favorable environment with warm
SSTs and lower shear. An increased rate of intensification should
take place in the 48 to 72 hour time frame, and Karl is expected to
reach hurricane strength by the end of that period. The official
intensity forecast has been nudged slightly downward based on the
latest guidance, however it is still on the upper end of the
guidance spread.

The center of Karl continues pushing west near the 20th parallel
with an initial motion of 275 at 12 kt. Karl is expected to make a
turn toward the west-northwest shortly and should reach the western
edge of the subtropical high during the next 48 hours, turning to
the northwest by day 2 and to the north by day 4. Karl will then
accelerate to the northeast as it gets picked up by the westerlies
ahead of an upper level trough. Global model guidance continues to
show considerable spread into the day 5 period. The ECMWF is
significantly slower than the other models because the upper level
trough does not pick up Karl. The official track forecast follows
close to the previous forecast and remains near a consensus of the
GFS and ECMWF.

FORECAST POSITIONS AND MAX WINDS

INIT 20/2100Z 20.1N 55.2W 35 KT 40 MPH
12H 21/0600Z 20.8N 57.0W 35 KT 40 MPH
24H 21/1800Z 22.3N 59.2W 40 KT 45 MPH
36H 22/0600Z 24.1N 61.4W 45 KT 50 MPH
48H 22/1800Z 25.6N 63.5W 55 KT 65 MPH
72H 23/1800Z 28.5N 65.5W 70 KT 80 MPH
96H 24/1800Z 32.5N 61.5W 85 KT 100 MPH
120H 25/1800Z 38.5N 51.0W 80 KT 90 MPH

$$
Forecaster Krekeler/Berg

[Kazmit]

They expect it to turn WNW shortly, so the westward motion will not affect the long term track of Karl that much.

The center of Karl continues pushing west near the 20th parallel
with an initial motion of 275 at 12 kt. Karl is expected to make a
turn toward the west-northwest shortly and should reach the western
edge of the subtropical high during the next 48 hours, turning to
the northwest by day 2 and to the north by day 4. Karl will then
accelerate to the northeast as it gets picked up by the westerlies
ahead of an upper level trough. Global model guidance continues to
show considerable spread into the day 5 period. The ECMWF is
significantly slower than the other models because the upper level
trough does not pick up Karl. The official track forecast follows
close to the previous forecast and remains near a consensus of the
GFS and ECMWF.

[emeraldislenc]

what does it mean " that it doesn't pick it up.?"

[AutoPenalti]

what does it mean " that it doesn't pick it up.?"

Essentially Karl doesn't sniff the weakness to its north, and turn poleward. Trough doesn't pick up Karl = Karl continues to the west.

A weaker Karl would be less inclined to feel the weakness, whereas a stronger Karl would move poleward.

[floridasun78]

what does it mean " that it doesn't pick it up.?"

time will tell it depend how strong it get if high forecast weakening allow move nw and north and ne remember this moement to west was not forecast was forecast keep moving wnw and nw by thur

[floridasun78]

other thing keep player is ull to west keeping weak

[Emmett_Brown]

what does it mean " that it doesn't pick it up.?"

Essentially Karl doesn't sniff the weakness to its north, and turn poleward. Trough doesn't pick up Karl = Karl continues to the west.

A weaker Karl would be less inclined to feel the weakness, whereas a stronger Karl would move poleward.

Actually, the ECMWF still shows Karl being captured by the trough, just 12-24 hours later than the GFS, which accounts for the spread in positions. EC still recurves it and passes it south of, but close to, Bermuda.

[Emmett_Brown]

Recon not finding much wind per the graphic on Tidbits. Seems like a TD as others have mentioned.

[Hammy]

Karl is headed towards dissipation within 24 hours given the low-level structure--it's even worse than I expected based on satellite. No way is this becoming a hurricane.

[ScottNAtlanta]

There is some really strong bursting to the east of the LLC. I would not be surprised to see the center reform there.

[abajan]

Karl is headed towards dissipation within 24 hours given the low-level structure--it's even worse than I expected based on satellite. No way is this becoming a hurricane.

Why am I getting a strong sense of déjà vu?

[Hammy]

Karl is headed towards dissipation within 24 hours given the low-level structure--it's even worse than I expected based on satellite. No way is this becoming a hurricane.

Why am I getting a strong sense of déjà vu?

If you're referring to Hermine, it was not under increasing 40-50kt wind shear when the forecasts had originally been for a decrease. The shear has been handled terribly with this, and based on recon there is no longer a circulation at the moment.

[floridasun78]

still moving west i cannot tell looking sat pic?

[gatorcane]

Looks west to me. Also 00z best track has it moving 270 at 12 knots

http://rammb.cira.colostate.edu/ramsdis ... display=12