511 
WTNT34 KNHC 272035
TCPAT4

BULLETIN
Post-Tropical Cyclone Helene Advisory Number  18
NWS National Hurricane Center Miami FL       AL092024
400 PM CDT Fri Sep 27 2024

...HELENE STILL PRODUCING CATASTROPHIC FLOODING OVER PORTIONS OF
THE SOUTHERN APPALACHIANS AND TENNESSEE VALLEY...
...FUTURE ADVISORIES WILL BE ISSUED BY THE WEATHER PREDICTION
CENTER...


SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...37.5N 85.5W
ABOUT 50 MI...80 KM SSE OF LOUISVILLE KENTUCKY
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 17 MPH...28 KM/H
MINIMUM CENTRAL PRESSURE...984 MB...29.06 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

For storm information specific to your area, please monitor 
products issued by your local National Weather Service forecast 
office.

DISCUSSION AND OUTLOOK
----------------------
At 400 PM CDT (2100 UTC), the center of Post-Tropical Cyclone Helene
was located near latitude 37.5 North, longitude 85.5 West. The
post-tropical cyclone is moving toward the north-northwest near 17
mph (28 km/h). A slowdown in forward speed is expected, and the 
system is forecast to stall over the Tennessee Valley late tonight 
and through the weekend.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Continued weakening is expected during the next couple of days.

The estimated minimum central pressure is 984 mb (29.06 inches).


HAZARDS AFFECTING LAND
----------------------
Key Messages for Helene can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC
and on the web at hurricanes.gov/text/MIATCDAT4.shtml

RAINFALL: Over portions of the central and southern Appalachians, 
Helene is expected to produce additional rainfall amounts of 1 to 2 
inches leading to widespread total rainfall accumulations of 6 to 12 
inches, with isolated totals exceeding 20 inches. This rainfall will 
result in catastrophic and potentially life-threatening flash and 
urban flooding, along with record level river flooding in many 
instances. Numerous significant landslides are expected in steep 
terrain across the southern Appalachians. Elsewhere, 1 to 3 inches 
of rainfall is expected across portions of the Ohio Valley through 
Sunday evening.

For a complete depiction of forecast rainfall associated with 
Tropical Storm Helene, please see the National Weather Service Storm 
Total Rainfall Graphic, available at 
hurricanes.gov/graphics_at4.shtml?rainqpf and the Flash Flood Risk 
graphic at hurricanes.gov/graphics_at4.shtml?ero. 

For a list of rainfall observations (and wind reports) associated 
this storm, see the companion storm summary at WBCSCCNS4 with the 
WMO header ACUS44 KWBC or at the following link:
www.wpc.ncep.noaa.gov/discussions/nfdscc4.html. 

TORNADOES: Isolated tornadoes are possible this afternoon and 
evening over southern Virginia and northeast North Carolina.

SURF: Swells generated by Helene will affect the coasts of Georgia
and the Carolinas during the next day or so.  These swells are
likely to cause life-threatening surf and rip current conditions.
Please consult products from your local weather office.


NEXT ADVISORY
-------------
This is the last public advisory issued by the National Hurricane 
Center on Helene.  Future information on this system can be 
found in Public Advisories issued by the Weather Prediction Center 
beginning at 1000 PM CDT, under AWIPS header TCPAT4, WMO 
header WTNT34 KWNH, and on the web at www.hurricanes.gov.

Rainfall forecasts for the United States can always be found at 
https://www.wpc.ncep.noaa.gov/qpf/qpf2.shtml 
and outlooks of flash flood risks can be found at 
https://www.wpc.ncep.noaa.gov/qpf/excessive_rainfall_outlook_ero.php
.

$$
Forecaster Cangialosi