By: Jeff Masters and Bob Henson From Weather Underground 5:36 PM GMT on October 08, 2016

Hurricane Matthew made landfall near 11 am EDT Saturday about 25 miles northeast of Charleston, South Carolina as a Category 1 hurricane with 75 mph winds. During the past two high tide cycles, Matthew has pushed a historic and destructive storm surge to the coasts of northern Florida, Georgia and South Carolina, bringing coastal water levels that were the highest to third highest ever observed. The powerful hurricane, diminished to Category 2 strength with 105 mph winds early Saturday morning, nonetheless had a very large area of strong winds that were able to pile up a massive dome of water that was focused by the arc-shaped curve of the coast into a record-height storm surge. As of 8 am EDT Sunday, October 9, here were the approximate peak storm surges observed over the preceding 48 hours at all the tide gauges with a long-term period of record along the coasts of northern Florida, Georgia, South Carolina, North Carolina, and Virginia (storm surge is the added water produced by a storm atop the normal tidal cycles):

7.8’ Fort Pulaski, GA
6.4’ Fernandina Beach, FL
6.1’ Charleston, SC
4.5’ Mayport, FL
4.4’ Springmaid Pier, SC
4.1’ Wilmington, NC
4.1′ Money Point (Norfolk), VA
3.5′ Sewells Point (Norfolk), VA
3.3′ Chesapeake Bay Bridge Tunnel, VA
2.6’ Beaufort, NC
Figure 1. In Savannah, GA, a car is stranded in waist-deep water near Ogeechee Road and Stiles Avenue on Saturday morning, October 8. Image credit: Savannah-Chatham Metropolitan Police Department.

Five tide gauges with long-term historical records along this stretch of coast set all-time records on Friday through Sunday for their highest water level (also called the storm tide, or the water level measured relative to high tide, MHHW):

Fort Pulaski, Georgia: 5.06’
Previous record: 3.40’ during the October 15, 1947 hurricane (records since 1935.)

Sewells Point, VA: 5.86’ Previous record: 5.26’, during the August 23, 1933 hurricane (records since 1927.)

Chesapeake Bay Bridge Tunnel, VA: 5.69’ Previous record: 4.66’, during the 11/12/2009 Nor’easter (records since 1975.)

Wilmington, NC: 3.53’ Previous record 3.47’, during Hurricane Hazel on October 15, 1954 (records since 1935.)

Mayport, FL: 3.28’
Previous record: 2.47’, during Hurricane Jeanne on September 27, 2004 (records since 1928.)

Near-record high water levels were observed at three other stations:

At Charleston SC, the water level during the Saturday morning high tide was the third highest on record: 3.53’. The record: 6.76’ during Hurricane Hugo on September 21, 1989; second highest, 4.47’ during the August 11, 1940 hurricane (records since 1921.)

At Fernandina Beach, FL, the water level during Friday afternoon’s high tide was the second highest on record: 4.17’. The record: 6.91’ during the October 2, 1898 hurricane (records since 1897.)

At Springmaid Pier, SC the water level during Saturday afternoon’s high tide was the second highest on record: 2.66’. The record 3.65’, during the January 1, 1987 nor’easter (records since 1957.)

Figure 2. Hurricane Matthew radar at 11 am EDT Saturday, October 8, 2016, as seen on our wundermap with the storm surge layer turned on. A storm surge of 5.4’ was indicated near Georgetown, South Carolina, with 3.5’ at Wilmington, North Carolina.

More high storm surges coming to SC, NC
Matthew will continue to track right along the coast of South Carolina this afternoon, then turn more to the northeast and track just south of the North Carolina coast Saturday night through Sunday morning. This track will push a dangerous storm surge of near record-high proportions to the coast, with NHC predicting inundations of 5 – 7’ possible from Charleston, SC to Cape Fear, and lower heights of 2 – 4’ for the coast of southern North Carolina farther to the east.

You can track Matthew’s storm surge using our wundermap with the “Storm Surge” layer turned on, the NOAA Tides and Currents storm page for Matthew or storm surge expert Dr. Hal Needham’s U-SURGE page for Matthew. Dr. Needham has some excellent information on the storm surge history of the north Florida to southern South Carolina coast in a Friday morning blog post, The “Protected Coast” is Now the Most Dangerous Place of All.
Figure 3. Multi-sensor analysis of rainfall for the 24 hours ending at 8:00 am EDT Saturday, October 8, 2016. Image credit: NOAA/NWS Advanced Hydrologic Prediction Service.

Record atmospheric moisture contributing to Matthew’s deluge
Weakening winds and a track just offshore hasn’t impeded the ability of Hurricane Matthew to produce vast amounts of rain along and near the Southeast coast, as the storm took advantage of all-time record levels of atmospheric moisture. A special balloon sounding launched at 2 am EDT Saturday from Charleston, South Carolina, measured the highest amount of moisture in the air ever recorded there: a precipitable water level of 2.93” (previous record: 2.70” on August 15, 2010.) The Jacksonville, Florida upper-air station also set an all-time record for atmospheric moisture in their 8 pm Friday night balloon sounding: 2.85” of precipitable water, beating the previous record of 2.82” set on July 20, 1993. Precipitable water is the total amount of liquid water that would cover the ground over a given location if all the moisture in a column of air above was condensed. Balloon soundings of the atmosphere have records extending back to 1948.

Twenty-four hour rainfall amounts from Matthew of 2” – 5” were common across the eastern half of north Florida, with much greater totals piling up toward the north. The calendar-day total of 6.28” at Jacksonville International Airport on Friday made for the city’s fifth wettest October day on record. In Savannah, Georgia, the 8.94” of rain recorded on Friday was the city’s second-largest calendar-day rainfall on any date, beaten only by 9.02” on September 16, 1924. Records in Savannah go back to 1871. Several more inches of rain fell early Saturday as the eyewall continued rolling over the city, and Savannah’s 24-hour total through 8 am EDT was 11.50”.

Some of the higher 24-hour totals reported on Saturday morning from the CoCoRaHS volunteer observing network:

13.86” – Garden City, GA
12.90” – Reevesville, SC
11.00” – Hilton Head Island, SC*
11.00” – 8 miles S of Manning, SC*
10.00” – Summerville, SC*
9.70” – 7 miles WSW of Santee, SC
9.70” – NWS/Charleston, SC
9.39” – 12 mi N of Jacksonville, FL
[* = minimum value, as the rain gauge overflowed]
Figure 4. Rainfall predicted for the two-day period from 8 am EDT Saturday, October 8, 2016 to 8 am Monday, October 10. Image credit: NHC, via NOAA/NWS/WPC.

Major flash flood threat over southeastern Carolinas this weekend
Residents of parts of North and South Carolina must be having deja vu this morning, as torrential rains from Matthew are arriving almost precisely one year after the catastrophic deluge that caused $2 billion in damage during the first week of October 2015. A swath from around Charleston to Columbia, SC, was especially hard hit during the 2015 deluge. As Matthew continues its track just offshore, heavy rains will continue to deluge areas within about 100-150 miles of the Atlantic, with the heaviest amounts closest to the coast (see Figure 4.) At midday Saturday, flash flood watches and warnings were plastered across coastal counties from Georgia to Delaware, including the Hampton Roads area of southeast Virginia. A flash flood emergency was issued for several counties near Fayetteville, NC, where Matthew has already produced more than 8” of rain. The stage for severe flooding was set by rains that topped 10” just west of Fayetteville over the prior 10 days. A separate flash flood emergency was in effect for areas near the Grand Strand series of beaches in South Carolina.

Larger-scale river flooding may become a serious concern by early next week in some areas, especially the coastal plain of North Carolina. The N.E. Cape Fear River near Chinquapin was projected to crest at 22.6 feet on Tuesday. That would tie the crest from January 1, 1928, and fall behind only the record 23.51 feet observed during Hurricane Floyd in 1999.

Forecast: Matthew will die Sunday night
Satellite loops on Saturday morning showed a quickly degrading hurricane, with a disheveled-looking area of heavy thunderstorms that were being distorted by high wind shear of 30 knots. Matthew will encounter steadily more unfavorable conditions for existence over the next three days. Wind shear will rise above 40 knots, the atmosphere will dry, and the ocean temperatures will cool. Matthew is now expected to get entangled with a front a few hundred miles south of Cape Hatteras, North Carolina on Sunday night, putting a final end to this long-lived tropical menace. The remnant non-tropical low pressure area that was Matthew may then loop to the south and southwest early next week, but will not be a high wind or heavy rain threat to The Bahamas.

Matthew was the 13th billion-dollar disaster in the U.S. this year
Insurance broker Aon Benfield, in an update sent out Friday evening, estimated that the total price tag for Matthew’s damages across the U.S., The Bahamas, Cuba and Haiti would run well into the billions of dollars, and would be the 13th billion-dollar weather-related disaster for U.S. so far this year. This is now the second-most number of such disasters (adjusted for inflation) in the U.S. in one year, behind 2011, which had seventeen. Property data firm CoreLogic is estimating $4 – $6 billion in insured U.S. losses from Matthew; total losses are typically double insured losses.
Figure 5. Women walking down the street in Jeremie, southwest Haiti, after the city was devastated by Hurricane Matthew. Foto: Logan Abassi UN/MINUSTAH.

Portlight and Lambi Fund of Haiti disaster relief charities need your help
The Portlight.org disaster relief charity, founded and staffed by members of the wunderground community, is responding to Hurricane Matthew. Portlight is working with their partners and stakeholder organizations throughout the affected region to ensure the needs of people with disabilities are well met. It’s important to note this includes people in directly impacted areas as well as the tens of thousands of evacuees. You can check out their progress on the Portlight Blog or donate to Portlight’s disaster relief fund at the portlight.org website.

A note from Jeff Masters: For over ten years, I’ve been a big booster of and donor to the Lambi Fund of Haiti, which is very active in disaster relief and disaster prevention, including promotion of reforestation efforts, use of alternative fuels, and infrastructure improvements at a grass-roots level to help avert future flood disasters.

What Lambi Fund is doing for their Hurricane Matthew response:
• Utilizing Regional Monitors and the active Partner Organizations (22 projects in portfolio) to survey the immediate needs in the South and Northwest in order to provide a primary response to these urgent needs
• Providing $150,000 for urgent relief during the first phase of their response while completing a needs assessment of the resources needed for the second phase, which will be to “Repair and Restore” the 22 active organizations’ projects that have been devastated
• Support the process of repairing the infrastructure damages (already established: 4 mills down in the Northwest, need to repair gardens, supply soil and nutrients essentially starting gardens over from scratch)

You can make your donation online at http://www.lambifund.org or send your funding support to:

Lambi Fund of Haiti
1050 Connecticut Avenue, Suite 500
Washington DC 20036

We’ll be back with our next update by Sunday afternoon.

Jeff Masters and Bob Henson

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