Chapter 1: Defining the Mid-Summer Drought Chapter 2: Mid-Summer Drought Forcings Chapter 3: Predictability for mid-summer rainfall Chapter 4: The Sequel

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Mr. Joseph Occupation: cabbage farmer Location: Flagaman, Jamaica

Martin Hilton Occupation: tomato farmer Location: Potsdam, Jamaica

Leroy Dixon Occupation: tomato / cassava farmer Location: Potsdam, Jamaica

Earl Bent Occupation: melon farmer Location: Top Hill, Jamaica

Donovan Campbell Occupation: PhD student Location: UWI Mona

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Intra-Americas Sea “Mid-Summer Drought”

The early and late summer is wet, but the middle of my

summer is usually hot and dry. What do you call this?

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This is what we think, but can you tell us what causes our mid-summer

drought?

* Courtesy of Donovan Campbell from The University of The West Indies at Mona

El Nino composite precipitation time series

Some people tell me that the Pacific can influence our rainfall. Is this true?

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Sea level pressure (dry MSD composite)

Sea level pressure (wet MSD composite)

spring NAO pattern

Well, then does the Atlantic play a role

too?

North Atlantic Subtropical High

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Allen et al. 2010

Observed

A) Observed simultaneous and lagged covariance statistics are used to predict the future state of a dynamical system.

B) The state system described by the LIM is constructed based on physical mechanisms that govern the system.

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� �

*Alexander et al., 2008, Journal of Climate

( represents the best “forecast” for 𝑥(𝑡 + 𝜏 given 𝑥(𝑡 )

1.

2.

3.

4.

STATE SYSTEM

Simultaneous and lagged covariance matrix

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5 x 5

matrix

SST SST

SLP SLPd

NAO NAOdt

precip precip

zonal wind zonal wind

( the observed simultaneous and lagged covariance statistics matrix )

( these are the state variables that describe the physical system )

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• Investigate MSD “regionality”

within the IAS with farmer

interviews in the eastern

Caribbean (hopefully this

summer)

• Improve our MSD conceptual

model

• Exploit the LIM method to

forecast mid summer rainfall

anomalies within the IAS

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