Weather Outlook

Weather OutlookWeather Outlook

March 9, 2004

presentspresents

The 2004 SeasonThe 2004 Season

Ed KieserEd Kieser

Global Weather Global Weather

South AmericaSouth AmericaSouth AmericaSouth America

Argentina soil moisture has Argentina soil moisture has improved.improved.

Southern Brazil has dry pockets, Southern Brazil has dry pockets, but many areas will receive rain but many areas will receive rain this week.this week.

Northern growing areas of Brazil Northern growing areas of Brazil remain way too wet. Yields have remain way too wet. Yields have been reduced.been reduced.

Highlights:

South AfricaSouth AfricaSouth AfricaSouth Africa

Crop conditions remain better than Crop conditions remain better than usual because of frequent rain of usual because of frequent rain of late.late.

Dry and warmer weather is needed Dry and warmer weather is needed for crop maturation.for crop maturation.

Highlights:

U.S. Weather U.S. Weather

U.S. MidwestU.S. MidwestU.S. MidwestU.S. Midwest

Concern about a possible wet start Concern about a possible wet start to the planting season.to the planting season.

A favorable start to crop A favorable start to crop development is expected once development is expected once plants are planted and established.plants are planted and established.

More uncertainty about later into More uncertainty about later into the summer.the summer.

Highlights:

U.S. DeltaU.S. DeltaU.S. DeltaU.S. Delta

The soil is saturated in many areas.The soil is saturated in many areas. Pre-planting fieldwork and early Pre-planting fieldwork and early

planting will remain slow.planting will remain slow.

Highlights:

Central PlainsCentral PlainsCentral PlainsCentral Plains

Drought continues in southwestern Drought continues in southwestern Nebraska, eastern Colorado, and Nebraska, eastern Colorado, and far western Kansas.far western Kansas.

Other areas not as dry.Other areas not as dry. Winterkill suspected in some areas.Winterkill suspected in some areas.

Highlights:

Northern PlainsNorthern PlainsNorthern PlainsNorthern Plains

Soil moisture generally favorable from Soil moisture generally favorable from melting snow and recent precipitation.melting snow and recent precipitation.

Some areas may be a little too wet in Some areas may be a little too wet in April and May.April and May.

Spring wheat planting may be slow, Spring wheat planting may be slow, but improved soil moisture has but improved soil moisture has prospects good for an improved crop prospects good for an improved crop this year.this year.

Highlights:

Climate Outlook - TemperatureMarch 2004


Long-Lead OutlooksLong-Lead OutlooksLong-Lead OutlooksLong-Lead Outlooks

EC – Equal Chances – Chances are EC – Equal Chances – Chances are 1/3 A, 1/3 N, 1/3 B.1/3 A, 1/3 N, 1/3 B.

A – Above Average.A – Above Average.N – Near Average.N – Near Average.B – Below Average.B – Below Average.

How to read them:

Long-Lead OutlooksLong-Lead OutlooksLong-Lead OutlooksLong-Lead Outlooks

Chance for “Above Average” Chance for “Above Average” increases to 40%, meaning:increases to 40%, meaning:

A – Odds for Above Average: 40%.A – Odds for Above Average: 40%.N – Odds for Near Average: 33 N – Odds for Near Average: 33

1/3%.1/3%.B – Odds for Below Average: 26 B – Odds for Below Average: 26

2/3%.2/3%.

Example: “40” around “A”:

Climate Outlook - PrecipitationMarch 2004

Climate Outlook - PrecipitationMarch 2004

Climate Outlook - TemperatureApril-June 2004

Climate Outlook - TemperatureApril-June 2004

Climate Outlook - TemperatureJune-August 2004

Climate Outlook - TemperatureJune-August 2004

Climate Outlook - PrecipitationApril-June 2004

Climate Outlook - PrecipitationApril-June 2004

Climate Outlook - PrecipitationJune-August 2004

Climate Outlook - PrecipitationJune-August 2004

Climate InfluencesClimate Influences

El NiñoEl NiñoEl NiñoEl Niño

Every 2-7 years. The interval Every 2-7 years. The interval between events is irregular.between events is irregular.

Maximum warming of the Pacific Maximum warming of the Pacific waters is generally observed waters is generally observed between December and February. between December and February.

When does it occur?

Normal ConditionsNormal Conditions

Convective LoopConvective Loop

EquatorEquator

120ºE120ºE 80ºW80ºW

El Niño ImpactsEl Niño ImpactsEl Niño ImpactsEl Niño Impacts

Bottom Line: There is little Bottom Line: There is little correlation between El Niño and correlation between El Niño and weather in Illinois, especially in weather in Illinois, especially in summer. summer.

Winters are often milder than Winters are often milder than average during a STRONG El Niño. average during a STRONG El Niño.

There is a good chance of less There is a good chance of less snowfall than average during a snowfall than average during a STRONG El Niño. STRONG El Niño.

Midwest:

Pacific Decadal OscillationPacific Decadal OscillationPacific Decadal OscillationPacific Decadal Oscillation

Know as the “PDO.” It’s a long-Know as the “PDO.” It’s a long-term ocean fluctuation of the term ocean fluctuation of the Pacific Ocean, with a cycle of Pacific Ocean, with a cycle of about 20 to 30 years.about 20 to 30 years.

What is it?


Evidence suggests that the PDO Evidence suggests that the PDO switched to the “cool” or “negative” switched to the “cool” or “negative” phase in the eastern Pacific Ocean in phase in the eastern Pacific Ocean in 1999. 1999.

It appears that this will act to steer the It appears that this will act to steer the jet stream farther north over the jet stream farther north over the western U.S.western U.S.

The “warm” or “positive” phase appears The “warm” or “positive” phase appears to have lasted from 1977-1998.to have lasted from 1977-1998.

What is happening?

Pacific Decadal OscillationPacific Decadal OscillationPacific Decadal OscillationPacific Decadal OscillationPDO Index:

Pacific Decadal OscillationPacific Decadal OscillationPacific Decadal OscillationPacific Decadal OscillationPDO Index:

+- - -+


The average national summer The average national summer temperature ranking tends to be temperature ranking tends to be lower than average. lower than average.

Annual precipitation tends to be less Annual precipitation tends to be less in the Midwest, Tennessee Valley, in the Midwest, Tennessee Valley, southern New England, and West.southern New England, and West.

Trend toward more precipitation in Trend toward more precipitation in the northern Rockies, Oklahoma, the northern Rockies, Oklahoma, eastern Texas, and the Mid-Atlantic eastern Texas, and the Mid-Atlantic Coast.Coast.

Impacts - Negative Phase:

North Atlantic OscillationNorth Atlantic OscillationNorth Atlantic OscillationNorth Atlantic Oscillation

Large scale oscillation of Large scale oscillation of atmospheric mass between the atmospheric mass between the subtropical high and the polar subtropical high and the polar low.low.

What is it?

North Atlantic OscillationNorth Atlantic OscillationNorth Atlantic OscillationNorth Atlantic Oscillation

The NAO occurs in the winter. It The NAO occurs in the winter. It varies from year to year, but can varies from year to year, but can remain in one phase for several remain in one phase for several years.years.

When does it occur?

NAO – Positive PhaseNAO – Positive PhaseNAO – Positive PhaseNAO – Positive Phase Stronger than usual subtropical high Stronger than usual subtropical high

pressure center and stronger than usual pressure center and stronger than usual Icelandic low.Icelandic low.

Increased pressure difference causes Increased pressure difference causes stronger winter storms, crossing the stronger winter storms, crossing the Atlantic on a more northerly track.Atlantic on a more northerly track.

Warm, wet winters in Europe and cold, dry Warm, wet winters in Europe and cold, dry winters in northern Canada and Greenland.winters in northern Canada and Greenland.

Mild and wet winters in the eastern U.S. Mild and wet winters in the eastern U.S.

NAO – Negative PhaseNAO – Negative PhaseNAO – Negative PhaseNAO – Negative Phase Weaker than usual subtropical high pressure Weaker than usual subtropical high pressure

center and weaker than usual Icelandic low.center and weaker than usual Icelandic low. Reduced pressure difference causes fewer Reduced pressure difference causes fewer

and weaker winter storms crossing the and weaker winter storms crossing the Atlantic on a more west-east pathway.Atlantic on a more west-east pathway.

Moist in the Mediterranean and cold in Moist in the Mediterranean and cold in northern Europe. northern Europe.

More cold air outbreaks and, thus, more More cold air outbreaks and, thus, more snow along the U.S. east coast. snow along the U.S. east coast.

Final ThoughtsFinal Thoughts

No Simple AnswersNo Simple AnswersNo Simple AnswersNo Simple Answers

The atmosphere operates on many The atmosphere operates on many time and space scales. They all time and space scales. They all influence the weather. influence the weather.

PDO, El Niño, NOA etc. do influence PDO, El Niño, NOA etc. do influence the jet stream (and the global scale), the jet stream (and the global scale), with the greatest impact on weather with the greatest impact on weather near the oceans and in and near the near the oceans and in and near the tropics. The impact is much reduced tropics. The impact is much reduced here. here.

Beware!

Decision MakingDecision MakingDecision MakingDecision MakingSome Advice: Listen to the weather rumors as they Listen to the weather rumors as they

impact the markets in the short term, impact the markets in the short term, but remember in the long term the but remember in the long term the actual weather is most important. actual weather is most important.

Follow the weather on a daily basis and Follow the weather on a daily basis and follow meteorologists that you can trust.follow meteorologists that you can trust.

All long-range weather forecasts have All long-range weather forecasts have little skill. Don’t make “all or nothing” little skill. Don’t make “all or nothing” decisions based on long-range forecasts.decisions based on long-range forecasts.

New WebsiteNew WebsiteNew WebsiteNew WebsiteIllinois State Water Survey: www.sws.uiuc.edu/warm www.sws.uiuc.edu/warm On left column, click on agriculture.On left column, click on agriculture. Has information about growing Has information about growing

degree days, 30 different pests, and degree days, 30 different pests, and more.more.

Tune toTune toIn-Depth Weather:In-Depth Weather: 5:35, 6:35, 7:35, 8:35, 9:35 AM5:35, 6:35, 7:35, 8:35, 9:35 AM 12:35, 4:33, 5:33 PM12:35, 4:33, 5:33 PM

Tune toTune toIn-Depth Weather:In-Depth Weather: 5:35, 6:35, 7:35, 8:35, 9:35 AM5:35, 6:35, 7:35, 8:35, 9:35 AM 12:35, 4:33, 5:33 PM12:35, 4:33, 5:33 PMSpecial Ag Weather Reports:Special Ag Weather Reports: 8:51 AM8:51 AM 2:32 PM2:32 PM

Tune toTune to

www.will.uiuc.eduwww.will.uiuc.eduOn the Web at:On the Web at:On the Web at:On the Web at:

Tune toTune to

Thank You!Thank You!

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Thank You!Thank You!

Questions?Questions?

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