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Hurricane Nate Discussion Number 14
NWS National Hurricane Center Miami FL AL162017
400 PM CDT Sat Oct 07 2017
Nate is sending mixed signals on its organization this afternoon.
On one side, the hurricane has a ragged central dense overcast with
a good complex of outer bands in the northeastern semicircle, and
there are hints of an eye trying to form. On the other side, the
cloud tops near the center have warmed significantly during the
past several hours, and there are signs that vertical shear is
starting to affect the storm. In addition, the eye only has
deep convection in the eastern semicircle in land-based radar
data. The last reports from an Air Force Reserve Hurricane Hunter
aircraft indicated that the central pressure was near 981 mb, with
flight-level and SFMR winds supporting an intensity of 80 kt. A
new aircraft is just starting its investigation of the hurricane.
Between the developing shear and the imminent landfall, Nate is
about out of time to strengthen. While not explicitly shown in the
intensity forecast, there could still be some intensification to
category 2 status in the next few hours. After landfall, Nate
should weaken rapidly as it moves through the eastern United
States. The cyclone is forecast to become a remnant low by 48 h,
extratropical near the 72 hr point, and dissipate completely
by 96 h.
The initial motion is now 345/20. Nate is moving around the
western end of a low- to mid-level ridge over Florida and the
western Atlantic, and the cyclone is expected to enter the mid-
latitude westerlies during the next 12-24 h. This should cause
Nate to turn northward in the next several hours, then turn
northeastward after 12-24 h. The new forecast track is similar in
both direction and speed to the previous track and lies near the
center of a tightly clustered set of guidance.
1. Nate is expected to bring life-threatening storm surge flooding
near and well east of where the center makes landfall, and a storm
surge warning is in effect from Grand Isle, Louisiana, to the
Okaloosa/Walton county line in Florida. Maximum flooding of 7 to 11
feet above ground level is expected in portions of southeastern
Louisiana and along the Mississippi coast.
2. Nate will bring hurricane conditions to portions of the northern
Gulf Coast from Louisiana to Alabama, where a hurricane warning is
in effect. The strongest winds are expected to occur primarily to
the east of the track of the center.
3. Nate's fast forward speed after landfall will bring
tropical-storm-force winds well inland across portions of the
southeastern U.S. Tropical storm watches and warnings are in effect
for portions of southeastern Mississippi, much of Alabama, and
4. Nate will bring heavy rainfall of 3 to 6 inches with isolated
totals of 10 inches east of the Mississippi River from the central
Gulf Coast into the Deep South, eastern Tennessee Valley, and
southern Appalachians through Monday, resulting in the potential for
flash flooding in these areas.
5. Moisture from Nate interacting with a frontal zone will also
bring 2 to 5 inches of rain with isolated totals of 7 inches across
the Ohio Valley and central Appalachians Sunday and Monday, which
will increase the risk for flash flooding across these locations.
FORECAST POSITIONS AND MAX WINDS
INIT 07/2100Z 28.4N 89.1W 80 KT 90 MPH
12H 08/0600Z 30.8N 89.2W 75 KT 85 MPH...INLAND
24H 08/1800Z 34.1N 87.0W 45 KT 50 MPH...INLAND
36H 09/0600Z 37.9N 83.1W 30 KT 35 MPH...INLAND
48H 09/1800Z 41.1N 77.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 10/1800Z 46.0N 63.0W 25 KT 30 MPH...POST-TROP/EXTRATROP