Tuesday, October 11, 2016

Hurricane Matthew Floodwaters Slowly Recede; Hurricane Watch for Nicole in Bermuda

By: Jeff Masters , 4:45PM,GMT on October 11,2016



 
Multiple rivers continue rampage above major flood stage in North Carolina as the state reels from a multi-billion dollar flood disaster wrought by the torrential rains from Hurricane Matthew over the weekend. At least 14 deaths have been reported across the state, according to weather.com. More than 1,500 people were stranded by high flood waters in the town of Lumberton on Monday (some fleeing to rooftops), and had to be rescued by helicopter and boat. More than 650,000 customers remained without electricity on Tuesday morning in the Southeast U.S., with about half of those in North Carolina and Virginia.


Figure 1. A boat passes a church in Nichols, S.C., Monday, Oct. 10, 2016. (AP Photo/Rainier Ehrhardt) 

Several more days of flooding coming
Most rivers in North Carolina have crested and are gradually falling in the wake of Matthew’s torrential rains, but some will remain above major flood stage for several more days. The flooding is the state’s worst since catastrophic Hurricane Floyd in September 1999, and in some areas is the worst on record. Several of the peak crests on North Carolina rivers this week from Mathew:

The Black River near Tomahawk crested at a record 27.92’ on Monday evening. Old record: 27.1’ on Sept. 18, 1999.

The Neuse River at Smithfield crested at a record 29.09’ on Monday; it is expected to fall below major flood stage by Wednesday morning. Old record: 27.4’ on September 8, 1996.

The Little River at Manchester crested at a record 31.73’ on Monday; it fell below major flood stage on Tuesday. Old record: 29.0’ on Sept. 19, 1945.

The Cape Fear River at W.O. Huske Lock crested at 68.4’ on Monday; it is expected to fall below major flood stage on Wednesday. This was its 2nd highest crest on record, behind 75.5’ on Sept. 22, 1945.

The Lumber River at Lumberton crested at a record (and unknown) height above 24.39’ on Monday, and is not expected to fall below is previous record flood height until Sunday. Old record: 20.48’ on Sept. 11, 2004


Figure 2. The Lumber River is experiencing record flooding that is expected to last all week. Image credit: NOAA/NWS Advanced Hydrologic Prediction Service.

Matthew’s impact elsewhere
Recovery efforts continue in the other regions hard-hit by Matthew, including Haiti (over 1,000 dead), The Bahamas (most costly hurricane in their history), Cuba (severe wind and storm surge damage to the eastern tip) and the Southeast U.S. states of Florida, Georgia and South Carolina (twelve dead and billions in damage.) Matthew is the most expensive Atlantic hurricane since Hurricane Sandy of 2012, and the deadliest since 2005, when both Katrina and Stan killed over 1,000 people. See our post from Monday for much more detail on Matthew’s impacts and records.


Figure 3. Latest satellite image of Nicole.

A Tropical Storm Warning and Hurricane Watch for Bermuda for Nicole
A Tropical Storm Warning and Hurricane Watch are up for Bermuda as a strengthening Tropical Storm Nicole heads towards a Thursday morning encounter with the island. Satellite imagery late Tuesday morning showed that Nicole has become much more organized since Monday, with a symmetric cloud pattern and an eye beginning to appear. The latest SHIPS model forecast diagnosed that wind shear had fallen sharply to the low range, 5 - 10 knots, with mid-level relative humidity levels that were decent for development, in the 50 - 60% range. Nicole is passing over the near-record-warm waters of the subtropical North Atlantic, with sea-surface temperatures of 29°C (84°F)— roughly 2°C above average. Record warm waters in this region helped boost Hurricane Gaston to Category 3 strength at latitude 30°N in late August. The 00Z Tuesday runs of our top four track models--the GFS, European, HWRF and UKMET models--all brought Nicole 40 - 90 miles west of Bermuda on Thursday morning. Our top three intensity models, the HWRF, SHIPS and LGEM, all predicted Category 1 hurricane intensity for Nicole at that time, as did the official NHC forecast as of 11 am EDT Tuesday. The SHIPS model in its 12Z Tuesday run was giving Nicole a 22% chance of rapidly intensifying into a Category 2 or stronger hurricane by Wednesday morning. Given the low shear and record warm waters Nicole has to work with, I expect Nicole will be a Category 2 hurricane on Thursday morning when it make its closest approach to Bermuda.


Figure 4. Typhoon Songda as seen at 00:45 UTC October 11, 2016. Image credit: NASA.

Watch for development in the Southwest Caribbean early next week
A broad area low pressure is expected to form in the waters of the Southwest Caribbean off the coast of Nicaragua early next week. A tropical depression form could form there next week, according to a number of the 70 forecasts of the GFS and European model ensembles. It is too early to be confident of a direction of motion for this system, but a movement to the northwest over Nicaragua and Honduras appears to be the most likely track, with a possible motion to the north over the central or western Caribbean later in the week.

Ex-Typhoon Songda to drench Northwest U.S.
In the Northwest Pacific, Category 3 Typhoon Sonda is heading northeast at 13 mph towards Alaska, and is expected to transition to a very wet extratropical storm with 45 mph winds on Thursday, when it will be a few hundred miles south of Alaska’s Aleutian Islands. Ex-Songda will then catch a ride with the jet stream and arrive off the coast of Washington on Saturday, when the storm is expected to intensify into a powerful low pressure system with a central pressure near 960 mb, bringing strong winds and heavy rains to the coasts of Oregon, Washington, and British Columbia. Rainfall of 6 to 10 inches, with local amounts over 12 inches, is possible western Washington south to northwestern California this week, due to a series of heavy rainstorms which include ex-Songa this weekend. East of the Cascades, rainfall could total 1 to 3 inches in the valleys and 3 to 7 inches in the foothills of the northern Rockies.

Jeff Masters

Flooding on the Neuse River in Raleigh (santiago2274)
The Neuse River Trail which follows close to the river is flooded over after the rainfall of Hurricane Matthew.
Flooding on the Neuse River in Raleigh
Matthew vs Detour Signs (Skyepony)
Matthew vs Detour Signs

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