2010 Hurricane Season Outlook and Considerations Jeff Garmon Warning Coordination Meteorologist David McShane Meteorologist in Charge NOAA – National Weather Service Weather Forecast Office Mobile, AL Jeff Garmon Warning Coordination Meteorologist David McShane Meteorologist in Charge NOAA – National Weather Service Weather Forecast Office Mobile, AL

National Weather Service Hurricane Forecasting Operations National Hurricane Center (Miami)National Hurricane Center (Miami) –Track and model forecast guidance –Broad-scale track and intensity parameters NWS Forecast Office (Mobile)NWS Forecast Office (Mobile) –Storm-scale impacts and timing Winds Surge Tornadoes Rainfall National Hurricane Center (Miami)National Hurricane Center (Miami) –Track and model forecast guidance –Broad-scale track and intensity parameters NWS Forecast Office (Mobile)NWS Forecast Office (Mobile) –Storm-scale impacts and timing Winds Surge Tornadoes Rainfall

The Good track forecast improvements

Changes to Tropical Cyclone Watch/Warning Lead Times in 2010 Lead time virtually unchanged while skill in track forecasting has improved NHC in fact frequently does issue watches and warnings at longer lead time than Directive indicates Key evacuation decisions now need to be made before 24 h and in some cases before 48 h Some jurisdictions, businesses, and schools still tag closure decisions to warning or watch Lead time virtually unchanged while skill in track forecasting has improved NHC in fact frequently does issue watches and warnings at longer lead time than Directive indicates Key evacuation decisions now need to be made before 24 h and in some cases before 48 h Some jurisdictions, businesses, and schools still tag closure decisions to warning or watch Coastal County Population, Texas to Maine Coastal County Population, Texas to Maine 53% of the U.S. population now lives within 50 miles of the coast Year Population

New for 2010 Tropical Storm / Hurricane Warnings will be issued for onset of Tropical Storm / Hurricane conditions 36 hours in advance. Tropical Storm / Hurricane Watches will be issued for onset of Tropical Storm / Hurricane conditions 48 hours in advance. Tropical Storm / Hurricane Warnings will be issued for onset of Tropical Storm / Hurricane conditions 36 hours in advance. Tropical Storm / Hurricane Watches will be issued for onset of Tropical Storm / Hurricane conditions 48 hours in advance.

The Bad Intensity no real gains

The Ugly – Un-forecasted Rapid Intensity Changes Even some of our best models miss the mark substantially

1932 – TS 180 miles south of GLS – Cat 4 at landfall less than 36h 1943, Alicia – both formed south of NOLA landfall less than 72h Audrey June 1957 – Cat 4 less then 72h after forming Anita (5), Celia (4), Camille (5) and Opal (4) all less then 96h 1932 – TS 180 miles south of GLS – Cat 4 at landfall less than 36h 1943, Alicia – both formed south of NOLA landfall less than 72h Audrey June 1957 – Cat 4 less then 72h after forming Anita (5), Celia (4), Camille (5) and Opal (4) all less then 96h Gulf of Mexico Rapid Intensifiers

1935 Labor Day Hurricane Category 1 to Category 5 in just 36h 7 am Sept 1 Cat 1 O O 1 am Sept 2 Cat 3 O 7 pm Sept 2 Cat 5

Storm surge uncertainty Extremely sensitive to errors in track, size, structure of wind field, angle of approach, and forward speed. Improvement in meteorological forecast over next decade will not negate the error function for surge forecast. Always expect enough track/intensity error to change the deterministic surge forecast...even 12 hours in advance. Extremely sensitive to errors in track, size, structure of wind field, angle of approach, and forward speed. Improvement in meteorological forecast over next decade will not negate the error function for surge forecast. Always expect enough track/intensity error to change the deterministic surge forecast...even 12 hours in advance.

Hurricane Advisory – Approximately 12 hr. before landfall NHC TRACK ERROR 12 hr. OUT 133 mph, 933 mb.

Rmax=25 mi (forecast) Surge Based on NHC -12 hr. Advisory

Actual Hurricane Track 30 mi. E of -12 hr. Advisory Forecast Track TRACK FORECAST ACTUAL TRACK 133 mph, 933 mb.

Rmax=40 mi Surge Based on NHC Storm Best Track

SLOSH Storm Surge (MEOW Cat 3 High Tide)…

L L H H L L H H 5,000 ft/850 mb 40,000 ft/200 mb HeatHeat HeatHeat HeatHeat HeatHeat Typical cruising altitude of commercial airplane Surface Effect of Vertical Wind Shear

El Nino – La Nina effects the position of the Jetstream Stronger southern stream upper jet = more wind shear over Gulf

What can we expect in 2010? El Nino is gone. Weak La Nina possible by mid to late summer. Decreased wind shear values will very likely mean a marked increase in activity compared to last year.Decreased wind shear values will very likely mean a marked increase in activity compared to last year. Significant wind shear due to a strengthening El Nino in 2009 resulted in a below average number of storms in the Atlantic Basin in 2009.Significant wind shear due to a strengthening El Nino in 2009 resulted in a below average number of storms in the Atlantic Basin in El Nino is gone. Weak La Nina possible by mid to late summer. Decreased wind shear values will very likely mean a marked increase in activity compared to last year.Decreased wind shear values will very likely mean a marked increase in activity compared to last year. Significant wind shear due to a strengthening El Nino in 2009 resulted in a below average number of storms in the Atlantic Basin in 2009.Significant wind shear due to a strengthening El Nino in 2009 resulted in a below average number of storms in the Atlantic Basin in 2009.

Model-Based El Niño/ La Niña (ENSO) Forecasts for the Niño 3.4 region The ENSO forecast models are predicting either ENSO-Neutral or La Niña conditions during the Atlantic hurricane season. The forecasts are increasingly indicating La Niña during Aug-Oct (ASO) 2010 (Figure courtesy of the International Research Institute). El Niño La Niña ENSO-Neutral

Pacific Ocean Conditions are favorable for La Niña to Develop 12 Weekly SST ( o C) Centered on 12 May 2010 El Niño has dissipated. Negative SST anomalies are now present in the equatorial Pacific. Subsurface Temperatures ( o C) 5-day Mean Centered 13 May 2010 Sub-surface temperatures are below average across the eastern half of equatorial Pacific. Equatorial Upper Ocean (0-300m) Heat Content 180 o -100 o W Since March 2010, the oceanic heat content has decreased markedly.

Expected Atlantic Basin Conditions During August-October Much Warmer Atlantic SSTs The predicted set of conditions forAugust-October 2010 mainly reflects the expected continuation of the tropical multi-decadal signal, above-average Atlantic Ocean temperatures, and a possible La Niña-related reduction in vertical wind shear.

Vertical Wind Shear (m s -1 ) 850-hPa Winds (m s -1 ) Tropical low-level westerly wind anomalies across eastern Pacific and Atlantic (Blue circle). Reduced vertical wind shear across heart of the MDR (Blue shading in green box). 200-hPa Winds (m s -1 ) Tropical upper-level easterly wind anomalies across eastern Pacific and Atlantic (Blue circle). Anticyclonic anomalies across tropical Atlantic in both hemispheres (Blue circle). 200-hPa Streamfunction 10 Recent Circulation Anomalies (Last 30 days) Typically Associated With Active Atlantic Phase of Tropical Multi-decadal Signal

SST departures in the MDR increased sharply during February-April 2010 (Top), and reached record levels in March and April. These departures are much larger elsewhere in the global Tropics (Bottom), indicating a local warming rather than global warming. Warmer SSTs in the Tropical Atlantic Latest Weekly SST Departures ( o C) Monthly SST Departures ( o C) The Main Development Region (MDR) for Atlantic hurricanes (Green Box) is currently experiencing record warm SSTs, with departures exceeding +1.5 o C nearly everywhere east of the Caribbean Islands.

The 2010 Atlantic Outlook in a Historical Perspective NOAA’s 2010 Atlantic hurricane season outlook indicates a 70% probability of an ACE range of 155%-270% of the median. An ACE value above 175% of median reflects an extremely active (also called hyperactive) season.

Based on this forecast, I will: A) Plan for more impacts than last year B) Cry “Holy &^%$” and move to Canada C) Do the same as every year A) Plan for more impacts than last year B) Cry “Holy &^%$” and move to Canada C) Do the same as every year 32

Seasonal Forecast 2010 …it only takes one… 33 Andrew

Track Map Tropical cyclones are born, live, and die in a variety of ways H

Oil Spill and Gulf Storms Direct hit of major storm – big surge more damaging than oil (life threatening and mix of toxic material from damage caused by surge) Weak storm or large storm passing well to south raises water levels 2 to 5 feet bringing oil to places previously untouched. Direct hit of major storm – big surge more damaging than oil (life threatening and mix of toxic material from damage caused by surge) Weak storm or large storm passing well to south raises water levels 2 to 5 feet bringing oil to places previously untouched.

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