BRAV/APC Meeting 06/23/2015

Mid Background Info, , Lightning and Safety, NWS Resources and More

Bill Sammler Warning Coordination Meteorologist – Wakefield, VA Tropical Cyclones Since 1870

Norfolk

Cape Hatteras Hurricanes Since 1870

Norfolk

1933 Hurricane

Cape Hatteras 2015 Hurricane Season Forecast

NOAA Forecast - Issued May 28th

“NORMAL” • 6‐11 Named Storms 12 storms

• 2‐5 Hurricanes 6 hurricanes

• 0‐2 Major Hurricane 2 major (Cat 3+) hurricanes

70% Chance of a Below Normal Season due to El Nino and relatively cool tropical Atlantic Ocean waters What Season is This?

1992 What Season is This?

1972 Hurricane Season Predictions The Seasonal Forecast Fallacy

Graphic Courtesy Steve Lyons What Season is This?

2010 Recent Improvements in Track Forecasts Have Resulted in Less Uncertainty 2005 Operational Cone

REMEMBER: 2015 Cone This Cone represents a 67% likelihood the storm will remain within that cone in the next 5 days. Up to 1/3 of the time, it won’t. Hurricane Threats STORM SURGE – The abnormal rise in water level directly associated with the wind and pressure forces associated with a hurricane

Storm Surge Example – hurricane makes at high tide

Storm Surge is highest in right forward quadrant near center as it crosses coast Storm Surge Storm Surge Factors • Storm Intensity and Size – Stronger = Higher Surge – Larger = Larger Area Affected • Storm Speed – Slower Often Means Higher Surge • Angle to Coast at Landfall – Perpendicular Maximizes Surge (Katrina) Storm Surge Example FACTOR = STORM INTENSITY

CAT 1 NNW 20 mph

CAT 3 NNW 20 mph Sandy vs. Irene

Sandy (2012)

Irene (2011) Storm Surge Example FACTOR = STORM SPEED

CAT 3 NNW 10 mph

CAT 3 NNW 30 mph Storm Surge Example FACTOR = ANGLE TO COAST

CAT 3 N 20 mph

CAT 3 WNW 20 mph Sandy vs. Irene

Sandy (2012)

Irene (2011) What About Evacuation?

Storm Motion Directions that Necessitate OBX Evacuation What About Evacuation?

Storm Motion Directions that Necessitate H.R. Evacuation

Storm Motion With significant Impact but Limited/No Evacuation Location of Impacts

• Favored region for tornadic development is the Eastern semi-circle

• Heaviest rainfall is often found on the western semicircle due to interaction with a frontal boundary and dry air entraining on east side of storm (northward moving storms)

• Winds generally strongest on the right (eastern) side of the storm after landfall, with friction lowering winds over land vs. water Fresh Water Flooding

Tropical Storm Debby – Sopchoppy, FL

Hurricane Irene – Vermont • Up to 43 inches of rain have fallen in 24 hours in a single (Alvin, TX – Claudette 1979). • TC rainfall potential depends most on the speed of motion. Slow- moving systems produce the most rainfall. • Tropical depressions or storms can produce more rain than hurricanes! Tropical Cyclone Rainfall - 1999

Floyd Track Tropical Cyclone Rainfall - 2011

Track Tropical Cyclone Rainfall Hurricane Irene – 2011 vs. Isabel - 2003

Track Tropical Cyclone Tornadoes

• Nearly 70% of landfalling hurricanes (1948‐2000) spawned at least 1 tornado • 40% spawn more than 3 tornadoes • Some hurricanes produce tornado “outbreaks” – Hurricane Beulah (1967): 141 – (2004): 117 – (2004): 101 – (2005): 90 – (1969): 80 – (2005): 43 Tropical Cyclone Tornadoes

All Tropical Cyclones Hurricanes

Tropical Depressions

Tropical Storms Tropical Cyclone Tornadoes Gaston, Frances and Ivan - 2004

Mainly Ivan – 9/17/2004

Mainly Gaston – 8/31/2004

69 Tornadoes in 3 weeks. Previous annual record – 31!! Hurricane Wind Examples Sandy vs. Irene

Sandy (2012)

Irene (2011) Irene –NHC vs. Reality

Irene (NHC) Irene (reality) Isabel –NHC vs. Reality

Isabel (NHC) Isabel (reality) Thunderstorm and Heat Safety Thunderstorm Hazards

Tornadoes Hail

Lightning Damaging Winds