september atlantic hurricane season update 06 september 2012 fred schmude stormwatch manager...
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September Atlantic Hurricane
Season Update06 September 2012
Fred SchmudeStormWatch ManagerImpactWeather, Inc. [email protected]
ImpactWeather helps our clients worldwide operate safely, effectively and efficiently in all weather conditions.
September Atlantic Hurricane
Season Update06 September 2012
Fred SchmudeStormWatch ManagerImpactWeather, Inc. [email protected]
• Review of the season through early September
• Why so many August storms (MJO, ENSO & CCKWs)
• Current Trends (Disturbance 45, Leslie and Michael)
• Forecast (ENSO, MJO and Kelvin)
• Seasonal update, including risk areas through October
Topics For Today
Today
Climatology suggests activity should increase significantly
soon
You are here
As of September 6th – 13 named storms
ErnestoFlorence
Gordon
Helene
Isaac Helene
Joyce
KirkLeslie
X
Isaac
6 Storms Formed after
the 15th!
Helene
IsaacX
X
August, 2012 Verification
Why so Active in August?
Favorable Geographic position for the MJO (Madden Julian Oscillation)
Madden-Julian Oscillation (MJO) a “pulse” of increased TC activity
originates in Indian Ocean and tracks eastward (40-day cycle)
Wheeler Diagram helps us track the position and strength of the MJO
Typically the MJO moves in a counterclockwise direction...from the Indian Ocean through the Pacific-Atlantic and Africa
MJO Position from Aug 17-31
IncreasinglyMore
Favorable
IncreasinglyLess
Favorable
UNFAVORABLE
UNFAVORABLE
FAVORABLEFAVORABLE
Regions 7 & 8 are unfavorable areas for TC development over the Atlantic Basin, mainly due to elevated wind shear
Regions 2 & 3 are favorable areas for TC development over the Atlantic Basin, mainly due to lowerwind shear
Why so Active in August?
Favorable Geographic position for the MJO (Madden Julian Oscillation)
El Niño development remained slow during August
El Niño Territory
Higher Wind Shear
La Niña Territory
Lower Wind Shear
Neutral
Slow increase into El Niño Territory
Why so Active in August?
Favorable Geographic position for the MJO (Madden Julian Oscillation)
El Niño development remained slow during August
Suppressive CCKW phase kept most of the tropical cyclones as either weak tropical storms or only brief category 1 hurricanes
New Term:Convectively Coupled Kelvin
Waves(CCKW)
• Somewhat Similar to MJO
• Period of 3-10 days
• Affect Tropics Mainly Between 0N-20N
• Development Occurs 1-2 Days After Passage of Wave Axis
• Suppressed Conditions Between Waves
Gulf Africa
Time
Longitude
Orange-Yellow Unfavorable
Current Trends
Current Tropics Summary
Disturbance 45 Hurricane Leslie
Hurricane Michael
Next Disturbance
SAL Remains Inactive
Disturbance 45: Satellite
Disturbance 45: Forecast Track
Disturbance 45: 5-day forecast
Disturbance 45: Cold Front Effect
5-Day Rainfall Projections (inches)
Leslie: Satellite
Leslie: 5-Day Forecast Track
Category 2 Hurricane
Category 1 Hurricane
Leslie: Scope of Winds
Leslie: Model Tracks
Michael: Satellite
Michael: 5-Day Forecast Track
L E S S
L IK E LY
T R A C K
LESS LIKELYTRACK
M O R E
L IK E LY
T R A C K
MORELIKELYTRACK
Forecast
Developing weak El Niño (Niño 3.4 already up to+0.9C)...More Shear?
El Niño Territory
Higher Wind Shear
La Niña Territory
Lower Wind Shear
Neutral
September / October Forecast
ENSO Forecast through October
Water Temperature Animation
Developing weak El Niño (Niño 3.4 already up to+0.9C)...More Shear?
MJO favors more neutral regions later in the month after the 20th
IncreasinglyMore
Favorable
IncreasinglyLess
Favorable
UNFAVORABLE
UNFAVORABLE
FAVORABLEFAVORABLE
MJO Forecasts
GFSECMWFUKMETCanadian
Developing weak El Niño (Niño 3.4 already up to+0.9C)...More Shear?
MJO favors more neutral regions later in the month after Sept 20 Unfavorable Kelvin phase over the next week to 10 days (suppressive phase west of 45W and favorable east of 45W)
Kelvin Wave Forecast
AfricaGulf
Non
Favorable
45W
Favorable
Sept 10
Sept 15
Sept 20
Current
UNFAVORABLE
UNFAVORABLE
UNFAVORABLE
UNFAVORABLE
FAVORABLE
FAVORABLE
FAVORABLE
• Developing weak El Niño (Niño 3.4 already up to+0.9C) = More Shear?
• MJO favors more neutral regions later in the month after Sept 20th
• Unfavorable Kelvin phase over the next week to 10 days (suppressive phase west of 45W and favorable east of 45W)
• Overall signals are mixed with either favorable to neutral MJO conditions, an uncertain ENSO effect and mixed KW signals
• Projecting 5 more named storms from September 6th through October (4 more in September and 1 more in October)
• Season Final Total Increased To: 18 - 10 - 3
Possible Development & Impact Regions Through October
H
o 18 Named Stormso 10 Hurricaneso 3 Intense Hurricanes (Cat. 3-4-
5)
Mean Flow Pattern
Monitor ForNear Shore
Activity
Slight C hance
Sept 12-22
Slight Chance Sept 12-22
Longer Track StormsStill Possible Through
Early October
