Arktos schrieb:Das ist jetzt bisschen abgefahren, aber könnte es irgendwann möglich sein, dass es ein Hurrikan über Südspanien ins Mittelmeer schafft? Durch das warme Wasser würde er dann nochmal sehr an Stärke gewinnen.

Zitat:Hurricane Larry Discussion Number  14
NWS National Hurricane Center Miami FL      AL122021
1100 PM AST Fri Sep 03 2021

Larry has had a distinct but slightly ragged 15 n mi wide eye
during the past few hours, while convective cloud tops within the
eyewall have been gradually cooling.  Intensity estimates have
responded, somewhat significantly, to the improved structure, and
TAFB and SAB Dvorak fixes at 0000 UTC were T5.5/102 kt and T5.0/90
kt, respectively.  In addition, objective UW-CIMSS ADT and SATCON
estimates are near 105 kt.  Larry has become a major hurricane, the
third of the Atlantic season, with estimated 100-kt sustained winds.

The hurricane is located due south of a mid-tropospheric high
centered over the central Atlantic, and continues to move toward
the west-northwest (285/14 kt).  Larry is generally expected to move
around the southwestern periphery of the high, turning northwestward
at a slower speed by Sunday and then north-northwestward by
Wednesday as a deep-layer trough moves eastward across the eastern
United States.  There is fairly high confidence in the track
forecast, with model guidance showing a below- to near-normal amount
of spread through day 5.  The new NHC track forecast is right along
the forecast from the previous advisory through day 3, and then
nudged slightly westward on days 4 and 5.  It should be noted that a
few of the consensus aids, including HCCA, are still a little bit
west of the official forecast at day 5, which might portend
additional westward nudges in future advisories.

By strict definition, Larry hasn't quite rapidly intensified since
this time yesterday, but it has still strengthened quickly over
waters that are considered only marginally warm (26-27 degrees
Celsius).  For the next couple of days, low shear, higher oceanic
heat content, and a more unstable environment should favor
additional intensification.  However, there are still indications
that Larry could run into an environment of higher shear and less
upper-level divergence in 2-3 days as it approaches a
mid-/upper-level trough currently located north and northeast of
the Leeward Islands.  In addition, internal processes within the
hurricane's core itself, such as eyewall replacement cycles, could
affect the intensity.  In light of all these factors, the NHC
intensity forecast relies on persistence to show additional
strengthening during the next 36 hours, and then holds Larry steady
through 60 hours at an intensity that is near the upper end of the
guidance.  Very gradual weakening is anticipated on days 3 through
5 while Larry heads in the direction of higher latitudes, yet the
hurricane is forecast to remain at major hurricane intensity for
the entire 5-day forecast period.

Significant ocean swells generated by Larry's growing wind field
are expected to reach the Lesser Antilles on Sunday, and then
spread westward to portions of the Greater Antilles, the Bahamas,
and Bermuda on Monday and Tuesday.  These swells could cause
life-threatening rip currents and high surf conditions.  Large
swells are also likely to spread to the east coast of the United
States by midweek.


FORECAST POSITIONS AND MAX WINDS

INIT  04/0300Z 15.5N  43.3W  100 KT 115 MPH
12H  04/1200Z 16.2N  45.3W  110 KT 125 MPH
24H  05/0000Z 17.4N  47.6W  115 KT 130 MPH
36H  05/1200Z 18.7N  49.7W  120 KT 140 MPH
48H  06/0000Z 20.0N  51.7W  120 KT 140 MPH
60H  06/1200Z 21.2N  53.6W  120 KT 140 MPH
72H  07/0000Z 22.4N  55.3W  115 KT 130 MPH
96H  08/0000Z 25.4N  58.5W  115 KT 130 MPH
120H  09/0000Z 29.5N  61.5W  105 KT 120 MPH

$$
Forecaster Berg

Zitat:Hurricane Larry Discussion Number  24
NWS National Hurricane Center Miami FL      AL122021
1100 AM AST Mon Sep 06 2021

Larry currently has an annular structure, with a 60 n-mi diameter
eye and a relatively thick eyewall.  High-resolution visible imagery
shows several meso-vortices rotating within the eye, which is
typically observed in strong hurricanes.  The upper-level outflow
has become better defined over the western portion of the
circulation, indicative of decreased shear in comparison to
yesterday. The advisory intensity is kept at 105 kt, in reasonable
agreement with the latest Dvorak estimates from TAFB and SAB.

Larry has slowed its forward speed a bit, and is now moving
northwestward near 9 kt.  There are no important changes in the
track forecast or reasoning from the previous advisory.  During the
next few days, the hurricane is expected to move around the western
periphery of a subtropical anticyclone over the central Atlantic,
turning northward and northeastward.  At this time, Larry is
forecast to pass east of Bermuda and make its closest approach to
the island on Thursday.  Given Larry's large size, some impacts
could be felt even if the center remains well east of the island as
forecast.  In 3-5 days, the cyclone should accelerate northeastward
ahead of a large mid-tropospheric trough moving through the
northeastern United States.  The official track forecast follows the
latest dynamical model consensus, and remains close to the previous
one.  Since the model guidance is in good agreement, this continues
to be a high-confidence track forecast.

Vertical shear is expected to remain low and the system will
continue to traverse warm SSTs for the next few days.  However, the
presence of dry mid-level air and the broad nature of the
hurricane's inner core will probably mitigate against significant
restrengthening.  Some fluctuations in intensity are possible for
the next 48 hours or so.  In 3-5 days, cooler waters and increasing
shear should cause gradual weakening.  Around the end of the
forecast period, the global models show the system beginning to
merge with a frontal zone near Newfoundland.  The official forecast
is on the high side of the model guidance suite and close to the
latest Decay-SHIPS prediction.

Key Messages:

1. Large swells generated by Larry are affecting the Lesser Antilles
and will spread to portions of the Greater Antilles, the Bahamas,
and Bermuda today through Tuesday.  Significant swells should reach
the east coast of the United States and Atlantic Canada by midweek
and continue affecting these shores through the end of the week.
These swells will likely cause life-threatening surf and rip current
conditions, and beachgoers and other interests along these coasts
are urged to follow the guidance of lifeguards and local officials
this week.

2. Larry is forecast to approach Bermuda during the next few days as
a large and powerful hurricane, bringing a risk of strong winds,
heavy rainfall, and coastal flooding to the island by the middle of
this week.  While it is too soon to determine the magnitude of these
hazards and potential impacts on Bermuda, interests there should
closely monitor the latest forecast updates during the next several
days.


FORECAST POSITIONS AND MAX WINDS

INIT  06/1500Z 22.1N  52.9W  105 KT 120 MPH
12H  07/0000Z 23.1N  54.0W  110 KT 125 MPH
24H  07/1200Z 24.5N  55.3W  110 KT 125 MPH
36H  08/0000Z 25.9N  56.6W  105 KT 120 MPH
48H  08/1200Z 27.5N  58.0W  100 KT 115 MPH
60H  09/0000Z 29.3N  59.6W  100 KT 115 MPH
72H  09/1200Z 31.6N  61.2W  95 KT 110 MPH
96H  10/1200Z 38.6N  60.0W  85 KT 100 MPH
120H  11/1200Z 49.0N  49.0W  70 KT  80 MPH...POST-TROP/EXTRATROP

$$
Forecaster Pasch