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KF5JRV > WX 09.10.18 13:40l 159 Lines 6725 Bytes #999 (0) @ NA
BID : 22770_KF5JRV
Read: GUEST
Subj: NWS NHC Atlantic WX - Oct 09
Path: IW8PGT<CX2SA<XE1FH<VE3UIL<VA7RBP<KF5JRV
Sent: 181009/1130Z 22770@KF5JRV.#NWAR.AR.USA.NA BPQ6.0.16
000
WTNT43 KNHC 090857
TCDAT3
Tropical Storm Leslie Discussion Number 52
NWS National Hurricane Center Miami FL AL132018
500 AM AST Tue Oct 09 2018
Leslie has been steady state overnight. The low-level center is
estimated to be on the southern side of a persistent area of deep
convection. The satellite intensity estimates are largely
unchanged, so the initial intensity is held at 55 kt for this
advisory.
The tropical storm is moving southeastward at 11 kt steered by the
flow on the southwest side of a broad mid- to upper-level trough.
This motion, but a slower pace, is expected during the next 24 to 36
hours as the trough pulls away. After that time, another trough is
expected to dig southward over the north Atlantic, which should
cause Leslie to accelerate east-northeastward. Although the models
are in fair agreement for the next few days, they remain in in poor
agreement on whether or not the trough will continue to carry Leslie
eastward or leave the storm behind around day 5. The GFS and ECMWF
have flip flopped, with the GFS now showing Leslie meandering over
the east Atlantic by day 5 and the ECMWF moving the system eastward
toward Morocco. The ensemble spread remains large in those two
global models and there has not been much run-to-run consistency
either. The NHC track forecast remains near the various consensus
aids, which is usually a good place to be when there is considerable
uncertainty like this.
Leslie should slowly strengthen during the next few days while
it moves over slightly warmer waters and into a more moist
environment. These favorable conditions should allow Leslie to
become a hurricane once again, likely within a day or two.
Weakening is expected to commence this weekend when Leslie is
forecast to move over cooler waters and into an atmosphere of
stronger shear and drier air, and the system is forecast to become
post-tropical by day 5. However, the long range intensity forecast
is strongly linked to where Leslie will be, so since the track
forecast is uncertain, the intensity prediction is likewise.
FORECAST POSITIONS AND MAX WINDS
INIT 09/0900Z 32.2N 43.9W 55 KT 65 MPH
12H 09/1800Z 30.8N 43.1W 55 KT 65 MPH
24H 10/0600Z 29.2N 42.5W 60 KT 70 MPH
36H 10/1800Z 28.1N 42.0W 65 KT 75 MPH
48H 11/0600Z 28.4N 40.5W 65 KT 75 MPH
72H 12/0600Z 31.2N 33.8W 75 KT 85 MPH
96H 13/0600Z 33.5N 23.0W 70 KT 80 MPH
120H 14/0600Z 34.0N 17.0W 55 KT 65 MPH...POST-TROPICAL
$$
Forecaster Cangialosi
000
WTNT44 KNHC 090857
TCDAT4
Hurricane Michael Discussion Number 11
NWS National Hurricane Center Miami FL AL142018
400 AM CDT Tue Oct 09 2018
Reports from an Air Force Reserve Hurricane Hunter aircraft a few
hours ago indicate that Michael's strengthening has paused, with
the maximum winds near 80 kt and a central pressure near 973 mb.
The aircraft also reported that the eyewall had become less
organized, which may be due to some dry air entrainment and shear.
The latest satellite imagery shows the convective banding becoming
better defined, and the next aircraft will shortly arrive in the
hurricane to provide better information on whether intensification
has resumed.
The initial motion is now 345/10. There is little change in either
the forecast philosophy from the previous advisory, as Michael
expected to remain caught between a deep-layer ridge centered off of
the U.S. east coast and a highly amplitude mid-latitude trough over
the U.S. Plains states and northern Mexico. This pattern should
steer the hurricane north-northwestward to northward for the next 24
h or so, followed by a turn to the northeast as Michael recurves
into the westerlies. Only minor tweaks have been made to the
previous forecast track, with Michael expected to make landfall in
the Florida Panhandle on Wednesday and cross the southeastern United
States Wednesday night and Thursday.
The large-scale models continue to forecast a decrease in the shear
later today, and thus Michael is forecast to intensify further
before landfall. The new intensity forecast follows the previous
forecast in showing Michael as a category 3 hurricane at landfall.
The cyclone should weaken significantly as it crosses the
southeastern United States, then it should re-intensify over the
western Atlantic as it undergoes extratropical transition between
72-96 h.
It should be noted that the location and magnitude of peak storm
surge flooding is very sensitive to small changes in the track,
intensity, and structure of the hurricane. Since there is still
uncertainty in all of these parameters, the official NHC storm surge
forecast and watch/warning areas includes various plausible
scenarios. Regardless of the eventual track and intensity of
Michael, life-threatening storm surge inundation is expected along
portions of the Florida Panhandle and Big Bend/Nature Coast, and the
storm surge watch has been upgraded to a storm surge warning for
parts of this area.
The NOAA G-IV aircraft is currently conducting a synoptic
surveillance mission over the Gulf of Mexico and dropsondes from
that mission will be assimilated into the 1200 UTC numerical models
runs.
Key Messages:
1. Life-threatening storm surge is likely along portions of the
coasts of the Florida Panhandle, Big Bend, and Nature Coast, and a
storm surge warning is in effect for these areas. Residents in these
areas should follow all advice given by their local officials.
2. A hurricane warning has been issued for portions of the Florida
Gulf Coast, and everyone in these areas should prepare for
life-threatening winds associated with the core of Michael.
Damaging winds will also extend inland across portions of the
Florida Panhandle, southern Georgia, and southeast Alabama as
Michael moves inland.
3. Heavy rainfall from Michael could produce life-threatening flash
flooding from the Florida Panhandle and Big Bend region into
portions of Georgia and South Carolina.
4. Tropical storm conditions will continue in portions of western
Cuba for a few more hours.
5. Michael is expected to produce heavy rainfall and flash flooding
over portions of western Cuba during the next day or so.
FORECAST POSITIONS AND MAX WINDS
INIT 09/0900Z 24.1N 85.9W 80 KT 90 MPH
12H 09/1800Z 25.7N 86.3W 90 KT 105 MPH
24H 10/0600Z 27.9N 86.4W 100 KT 115 MPH
36H 10/1800Z 29.9N 85.6W 105 KT 120 MPH
48H 11/0600Z 32.3N 83.4W 50 KT 60 MPH...INLAND
72H 12/0600Z 36.5N 75.5W 45 KT 50 MPH...OVER WATER
96H 13/0600Z 42.5N 60.5W 60 KT 70 MPH...POST-TROPTRATROP
120H 14/0600Z 49.0N 40.5W 55 KT 65 MPH...POST-TROPTRATROP
$$
Forecaster Beven
73 de Scott KF5JRV
Pmail: KF5JRV@KF5JRV.#NWAR.AR.USA.NA
email: KF5JRV@ICLOUD.COM
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