BULLETIN
Hurricane Zeta Advisory Number 17
NWS National Hurricane Center Miami FL AL282020
400 PM CDT Wed Oct 28 2020
...ZETA MAKING LANDFALL IN SOUTHEASTERN LOUISIANA...
SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...29.2N 90.6W
ABOUT 65 MI...100 KM SSW OF NEW ORLEANS LOUISIANA
MAXIMUM SUSTAINED WINDS...110 MPH...175 KM/H
PRESENT MOVEMENT...NNE OR 25 DEGREES AT 24 MPH...39 KM/H
MINIMUM CENTRAL PRESSURE...970 MB...28.65 INCHES
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
None.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Warning is in effect for...
* Mouth of the Atchafalaya River to Navarre Florida
* Lake Borgne, Lake Pontchartrain, Pensacola Bay and Mobile Bay
A Hurricane Warning is in effect for...
* Morgan City Louisiana to the Mississippi/Alabama border
* Lake Pontchartrain, Lake Maurepas, and Metropolitan New Orleans
A Tropical Storm Warning is in effect for...
* Mississippi/Alabama border to Walton/Bay County Line Florida
A Storm Surge Warning means there is a danger of life-threatening
inundation, from rising water moving inland from the coastline in
the indicated locations. For a depiction of areas at risk, please
see the National Weather Service Storm Surge Watch/Warning Graphic,
available at hurricanes.gov. This is a life-threatening situation.
Persons located within these areas should take all necessary actions
to protect life and property from rising water and the potential for
other dangerous conditions. Promptly follow evacuation and other
instructions from local officials.
A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area. Preparations to protect life and
property should be rushed to completion.
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area.
For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.
DISCUSSION AND OUTLOOK
----------------------
Observations from an Air Force Reserve Hurricane Hunter aircraft
indicate that Zeta is making landfall near Cocodrie, Louisiana.
At 400 PM CDT (2100 UTC), the center of Hurricane Zeta was located
near latitude 29.2 North, longitude 90.6 West. Zeta is moving toward
the north-northeast near 24 mph (39 km/h) A faster north-
northeastward motion is expected through tonight followed by an even
faster northeastward motion on Thursday and an east-northeastward
motion early Friday. On the forecast track, the center of Zeta will
make a second landfall along the Mississippi coast this evening,
and then move across the southeastern and eastern United States on
Thursday.
Maximum sustained winds are near 110 mph (175 km/h) with higher
gusts. Weakening will occur while Zeta moves over the southeastern
United States on Thursday.
Hurricane-force winds extend outward up to 35 miles (55 km) from the
center and tropical-storm-force winds extend outward up to 150 miles
(240 km).
The estimated minimum central pressure is 970 mb (28.65 inches).
HAZARDS AFFECTING LAND
----------------------
Key messages for Zeta can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT3, WMO header WTNT43 KNHC, and
on the web at
http://www.hurricanes.gov/text/MIATCDAT3.shtml.
STORM SURGE: Along the northern Gulf Coast, the combination of a
dangerous storm surge and the tide will cause normally dry areas
near the coast to be flooded by rising waters moving inland from the
shoreline. The water could reach the following heights above ground
somewhere in the indicated areas if the peak surge occurs at the
time of high tide...
Mouth of the Pearl River to MS/AL border...7-11 ft
MS/AL border to Dauphin Island AL...6-9 ft
Port Fourchon LA to the Mouth of the Mississippi River...6-9 ft
Mouth of the Mississippi River to the Mouth of the Pearl River
including Lake Borgne...5-7 ft
Mouth of the Atchafalaya River to Port Fourchon LA...4-6 ft
Mobile Bay...4-6 ft
Lake Pontchartrain...4-6 ft
Dauphin Island AL to AL/FL border...3-5 ft
AL/FL border to Navarre FL including Pensacola Bay...2-4 ft
Intracoastal City LA to the Mouth of the Atchafalaya River including
Vermilion Bay...1-3 ft
Lake Maurepas...1-3 ft
Navarre FL to Yankeetown FL including Choctawhatchee Bay and Saint
Andrew Bay...1-3 ft
Overtopping of local levees outside of the Hurricane and Storm
Damage Risk Reduction System is possible where local inundation
values may be higher than those shown above.
The deepest water will occur along the immediate coast near and to
the right of the landfall location, where the surge will be
accompanied by large and destructive waves. Surge-related flooding
depends on the relative timing of the surge and the tidal cycle,
and can vary greatly over short distances. For information
specific to your area, please see products issued by your local
National Weather Service forecast office.
WIND: Hurricane or Tropical Storm conditions are expected within
the Warning area on the northern Gulf Coast later this afternoon,
with tropical storm conditions already occurring. Tropical storm
conditions are also likely beginning within the Tropical Storm
Warning area on the northern Gulf Coast.
Damaging winds, especially in gusts, will spread well inland across
portions of southeastern Mississippi, Alabama, and northern Georgia
this evening through early Thursday morning, and into the Carolinas
and southeastern Virginia on Thursday. Wind gusts could be
especially severe across the southern Appalachian Mountains on
Thursday.
RAINFALL: Areas of heavy rainfall, both in advance of Zeta and
along the track of Zeta, will impact areas from the central Gulf
Coast to the Mid-Mississippi and Ohio Valleys, and eastward into
the southern to central Appalachians and Mid-Atlantic today through
Thursday. Rainfall totals of 2 to 4 inches with isolated amounts
of 6 inches are expected across these areas, resulting in flash,
urban, small stream, and minor river flooding.
TORNADOES: A few tornadoes are expected this afternoon through
tonight over southeastern parts of Louisiana and Mississippi,
southern Alabama, and the western Panhandle of Florida.
NEXT ADVISORY
-------------
Next intermediate advisory at 700 PM CDT.
Next complete advisory at 1000 PM CDT.
$$
Forecaster Pasch
Hurricane Zeta Discussion Number 17
NWS National Hurricane Center Miami FL AL282020
400 PM CDT Wed Oct 28 2020
The center of Zeta is in the Terrebone Bay area of Louisiana and
is making landfall near Cocodrie. Somewhat surprisingly, Zeta has
rapidly intensified this afternoon. Although the hurricane has been
moving over marginally warm SSTs and relatively low heat content
waters, it has intensified from 80 kt to 95 kt in about 6 hours. It
is possible that this intensification can be at least partly
attributable to a conducive interaction with with an upper-level
trough located a few hundred miles to the west-northwest of Zeta.
The 95-kt intensity estimate for Zeta is based on a blend of
flight-level, SFMR and dropsonde winds from an Air Force Reserve
Hurricane Hunter aircraft.
Since the center will either be interacting with land or moving over
land from this point, a weakening trend should begin tonight. The
official intensity forecast is close to the Decay-SHIPS guidance,
which should handle the exponential decay of wind seed for tropical
cyclones moving over land. In 24 hours or so, the global models
depict the system as being embedded in a front while it approaches
the United States east coast. Thus the official forecast shows an
extratropical cyclone at that point and beyond. After 48 hours, the
models show the low becoming elongated and absorbed into the frontal
zone.
Zeta has turned toward the north-northeast and the forward speed is
increasing, with the motion now 025/21 kt. The cyclone should
accelerate north-northeastward ahead of a 500-mb trough through
tonight. The system should then move even faster toward the
northeast, ahead of the trough, and across the southeastern and
eastern United States on Thursday. Post-tropical Zeta should move
east-northeastward, in the mid-level westerlies, into the Atlantic
Friday morning. The official track forecast follows the correct
model consensus, HCCA, rather closely.
Given Zeta's acceleration after landfall, strong winds are likely
to spread well inland over the southeastern U.S. overnight and
early Thursday.
KEY MESSAGES:
1. A life-threatening storm surge is beginning along portions of the
northern Gulf Coast, with the highest inundation expected to occur
somewhere between Port Fourchon, Louisiana, and Dauphin Island,
Alabama, especially along the Mississippi coast. Overtopping of
local, non-federal levee systems is possible within southeastern
Louisiana outside of the Hurricane and Storm Damage Risk Reduction
System.
2. Extremely dangerous hurricane conditions are spreading across
portions of the Hurricane Warning area along the southeastern
Louisiana coast and will spread to the Mississippi coast this
evening. Tropical storm conditions will spread into portions of the
Tropical Storm Warning area along the Alabama and far western
Florida Panhandle coasts in the next few hours.
3. Strong, damaging wind gusts, which could cause tree damage and
power outages, will spread well inland across portions of
southeastern Mississippi, Alabama, northern Georgia, the Carolinas,
and southeastern Virginia tonight and Thursday due to Zeta's fast
forward speed. Wind gusts could be especially severe across the
southern Appalachian Mountains on Thursday.
4. Through Thursday, heavy rainfall is expected from portions of
the central U.S. Gulf Coast into the Mid-Mississippi Valley, Ohio
Valley, southern to central Appalachians, and Mid-Atlantic States
near and in advance of Zeta. This rainfall will lead to flash,
urban, small stream, and minor river flooding.
FORECAST POSITIONS AND MAX WINDS
INIT 28/2100Z 29.2N 90.6W 95 KT 110 MPH...ON THE COAST
12H 29/0600Z 32.8N 87.0W 55 KT 65 MPH...INLAND
24H 29/1800Z 37.5N 78.8W 40 KT 45 MPH...POST-TROP/INLAND
36H 30/0600Z 41.0N 68.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
48H 30/1800Z 44.0N 57.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
60H 31/0600Z...DISSIPATED
$$
Forecaster Pasch