Hurricane Matthew. National Weather Service Wilmington NC. Steven Pfaff, WCM.

Transcription

1 Hurricane Matthew Threat Assessment for northeast South Carolina & southeast North Carolina National Weather Service Wilmington NC 515 PM EDT Monday October 3, 2016 Steven Pfaff, WCM Weather Forecast Office Wilmington, NC 1

2 New Information The official National Hurricane Center track has shifted to the west. As a result, the threat for the Southeast United States has increased. Maritime impacts are expected to be high to extreme later in the week. Southsouthwest swells from Matthew could begin impacting the beaches by Thursday combining with other easterly swells. Antecedent soil saturation from earlier heavy rainfall events could come into play later this week. Many areas between Lumberton, Florence, Georgetown, Myrtle Beach, and Wilmington are % above normal over the last 30 days. As a result, any heavy rainfall from Matthew could quickly lead to flash flooding. 2

3 Potential Impacts Given the uncertainty in the forecast it s too early to tell what specifically will occur after Hurricane Matthew moves north of the Bahamas. Other than a high confidence of dangerous maritime conditions developing later in the week flooding, surge, wind and tornado impacts will be highly dependent on the track of the storm. Three scenarios include: a direct hit with high impacts, a brush-by with some impacts especially along the coast, and a track staying farther off the coast with mainly marine impacts only. All interests in northeast SC and southeast NC are strongly encouraged to closely monitor this developing weather situation. Be prepared to act if it becomes apparent that direct impacts will occur. All marine interests off the Carolina coast should begin preparing for the development of dangerous winds and waves. Make plans to seek safe harbor and avoid being in or near the path of Hurricane Matthew. 3

4 Tropical Storm and Hurricane Probabilities The probability for Tropical Storm Winds has increased across southeast NC and northeast SC. Hurricane Force Wind Speed Probabilities are now showing up along the coast. These graphics are for a 120 hour period from 2 PM EDT Monday Oct 3 rd to 2 PM EDT Saturday Oct 8 th. 4

5 Official NHC 5 Day Forecast Track The official track has shifted to the west, placing the area firmly within the 5 Day forecast cone. Hurricane Matthew may move by as a strong to possibly major hurricane. Do not focus on the exact track of Matthew as it will shift overtime. Note, this is not an impact cone. Advisory #23 5 PM EDT Mon Oct 3, 2016 Position: 16.3N / 74.7W (225 Mi. SW of Port Au Prince Haiti) Movement: Toward the North at 7 mph Intensity: 140 MPH (Category 4) Min. Pressure: 940 MB or inches 5 PM NHC Advisory 23 Monday Oct 3, 2016 Hurricane Matthew 5 Day Forecast Cone *Note: statistically, one third of the time the storm can be outside of the 5 day error cone 5

6 Model Information Uncertainty increases over time with the models diverging some as the storm moves across the Bahamas. Overall, some of the operational models have shifted to the west compared to the previous run. Note: tropical cyclones can, and do, deviate from the model consensus. As a result, please refer to the official advisory from the National Hurricane Center. 6

7 Key Points The risk for receiving direct impacts from Hurricane Matthew has increased for the Southeast United States. Uncertainty in the track and intensity of Hurricane Matthew remains after the storm moves across the Bahamas. While specific flood, surge, and wind impacts are not known at this time for land areas, marine conditions will become dangerous with steep seas and strong winds later in the week. All residents should closely follow the progression of this storm and be prepared to take direct action in upcoming days. NEXT PDF BRIEFING: 8 AM EDT - Tuesday October 4,