Carolinas brace for Hurricane Florence; summery weather in Minnesota

Powerful Hurricane Florence is heading toward the Carolina coastline.

Here’s the view from above:

National Oceanic and Atmospheric Administration, via tropicaltidbits

National Weather Service radar was already showing bands of thunderstorms and heavy rain hitting portions of the North Carolina coast Thursday morning:

NWS radar, via College of DuPage

Florence’s maximum sustained winds were 110 mph Thursday morning, making Florence a Category 2 hurricane, but just barely. Florence is just 1 mph below Category 3 hurricane status.

The National Hurricane Center uses the Saffir-Simpson hurricane wind scale to categorize hurricanes:

NWS National Hurricane Center

Florence may reach low-end Category 3 status at times Thursday.

This note from the National Hurricane Center:

Here’s the Thursday morning update on Florence, from the National Hurricane Center:

Hurricane Florence Intermediate Advisory Number 56A

NWS National Hurricane Center Miami FL AL062018
800 AM EDT Thu Sep 13 2018

…SQUALLY RAIN BANDS WITH TROPICAL-STORM-FORCE WINDS MOVING ONSHORE
OF THE OUTER BANKS OF NORTH CAROLINA…
…LIFE-THREATENING STORM SURGE AND RAINFALL EXPECTED…

SUMMARY OF 800 AM EDT…1200 UTC…INFORMATION
———————————————-
LOCATION…33.1N 75.1W
ABOUT 170 MI…275 KM ESE OF WILMINGTON NORTH CAROLINA
ABOUT 220 MI…355 KM E OF MYRTLE BEACH SOUTH CAROLINA
MAXIMUM SUSTAINED WINDS…110 MPH…175 KM/H
PRESENT MOVEMENT…NW OR 315 DEGREES AT 12 MPH…20 KM/H
MINIMUM CENTRAL PRESSURE…956 MB…28.23 INCHES

WATCHES AND WARNINGS
——————–
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for…
* South Santee River South Carolina to Duck North Carolina
* Albemarle and Pamlico Sounds, including the Neuse and Pamlico
Rivers

A Storm Surge Watch is in effect for…
* Edisto Beach South Carolina to South Santee River South Carolina
* North of Duck North Carolina to the North Carolina/Virginia border

A Hurricane Warning is in effect for…
* South Santee River South Carolina to Duck North Carolina
* Albemarle and Pamlico Sounds

A Hurricane Watch is in effect for…
* Edisto Beach South Carolina to South Santee River South Carolina

A Tropical Storm Warning is in effect for…
* North of Duck North Carolina to Cape Charles Light Virginia
* Chesapeake Bay south of New Point Comfort

Interests elsewhere in the southeastern and mid-Atlantic states
should monitor the progress of Florence.

A Storm Surge Warning means there is a danger of life-threatening
inundation, from rising water moving inland from the coastline. 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 Storm Surge Watch means there is a possibility of life-
threatening inundation, from rising water moving inland from the
coastline.

A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area, in this case within the next 12
to 24 hours. Preparations to protect life and property should be
nearing completion.

A Hurricane Watch means that hurricane conditions are possible
within the watch area. A watch is typically issued 48 hours
before the anticipated first occurrence of tropical-storm-force
winds, conditions that make outside preparations difficult or
dangerous.

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
———————-
At 800 AM EDT (1200 UTC), the center of the eye of Hurricane
Florence was located by an Air Force Reserve reconnaissance aircraft
and NOAA Doppler weather radars to be near latitude 33.1 North,
longitude 75.1 West. Florence is moving slower toward the northwest
at about 12 mph (20 km/h). This general motion, accompanied by a
further decrease in forward speed, is expected to continue through
today. A turn to the west-northwest and west at an even slower
forward speed is expected tonight and Friday, and a slow
west-southwestward motion is forecast Friday night and Saturday. On
the forecast track, the center of Florence will approach the coasts
of North and South Carolina later today, then move near or over the
coast of southern North Carolina and eastern South Carolina in the
hurricane warning area tonight and Friday. A slow motion over
eastern South Carolina is forecast Friday night through Saturday
night.

Maximum sustained winds are near 110 mph (175 km/h) with higher
gusts. Little change in strength is expected before the center
reaches the coast, with weakening expected after the center moves
inland.

Florence is a large hurricane. Hurricane-force winds extend outward
up to 80 miles (130 km) from the center and tropical-storm-force
winds extend outward up to 195 miles (315 km).

The estimated minimum central pressure based on reports from the
the aircraft is 956 mb (28.23 inches).

HAZARDS AFFECTING LAND
———————-
STORM SURGE: 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 has the
potential to reach the following heights above ground if peak surge
occurs at the time of high tide…

Cape Fear NC to Cape Lookout NC, including the Neuse, Pamlico,
Pungo, and Bay Rivers…9-13 ft
North Myrtle Beach SC to Cape Fear NC…6-9 ft
Cape Lookout NC to Ocracoke Inlet NC…6-9 ft
South Santee River SC to North Myrtle Beach SC…4-6 ft
Ocracoke Inlet NC to Salvo NC…4-6 ft
Salvo NC to North Carolina/Virginia Border…2-4 ft
Edisto Beach SC to South Santee River SC…2-4 ft

The deepest water will occur along the immediate coast in areas of
onshore winds, 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.

RAINFALL: Florence is expected to produce heavy and excessive
rainfall in the following areas…

Coastal North Carolina into far northeastern South Carolina…20 to
30 inches, isolated 40 inches. This rainfall would produce
catastrophic flash flooding and prolonged significant river
flooding.

Rest of South and North Carolina into southwest Virginia…6 to 12
inches, isolated 24 inches.

WIND: Hurricane conditions are expected to reach the coast within
the hurricane warning area this evening or early Friday. Winds are
expected to first reach tropical storm strength by later this
morning or early this afternoon, making outside preparations
difficult or dangerous. Preparations to protect life and property
should be nearing completion.

TORNADOES: A few tornadoes are possible in eastern North Carolina
through Friday.

SURF: Swells generated by Florence are affecting Bermuda, portions
of the U.S. East Coast, and the northwestern and central Bahamas.
These swells are likely to cause life-threatening surf and rip
current conditions. Please consult products from your local weather
office.

The projected path of the center of Hurricane Florence, from the NHC:

NWS National Hurricane Center

Florence is a very significant hurricane:

Minnesota is summery

Most of Minnesota will see highs in the 80s Thursday afternoon, with some 70s in the far north.

Dew points will rise into the 60s across much of the southern half of Minnesota.

Highs will be in the 80s in about the southern half of Minnesota on Friday, but it’ll be cooler up north:

Saturday will feature a lot of 80s in central Minnesota, while some spots in the south touch 90 degrees:

Most of Minnesota will top out in the 80s on Sunday:

If these temps are too warm for you, you’ll be happy to know that Twin Cities metro area highs will retreat to the lower 70s by Tuesday.

Rain chances

Northwestern Minnesota has a chance of scattered showers and thunderstorms this Thursday, then the shower-thunderstorm chance expands to include about the northern half of Minnesota overnight and Friday.

Friday evening into early Saturday, there is a chance of scattered showers and thunderstorms in central and northern Minnesota.

The National Oceanic and Atmospheric Administration’s North American Mesoscale forecast model shows the potential rain pattern Friday evening through Saturday evening:

NOAA NAM simulated radar from Friday evening through Saturday evening, via tropicaltidbits

The color chart to the right of the loop refers to the strength of the signal that returns to the radar, not to the amount of rain.

Programming note

You can hear my live weather updates on Minnesota Public Radio at 7:49 a.m. Thursdays and Fridays, and at 7:35 a.m., 9:35 a.m. and 4:35 p.m. each Saturday and Sunday.