Presentation on theme: "Jim Noel Service Coordination Hydrologist March 2, 2012"— Presentation transcript:
1 Jim Noel Service Coordination Hydrologist March 2, 2012 NOAA/NWS Ohio River Forecast Center Climate Trends, Risk and Impacts on the Ohio Valley Ohio State University Severe Weather SymposiumJim NoelService Coordination HydrologistMarch 2, 2012
2 Climate Trends – Annually and Seasonally Today’s DiscussionClimate Trends – Annually and SeasonallyRisk from Cyclone Frequency ENSO, NAOClimate Impacts on Ohio2012 Seasonal OutlookQuestions/Comments
3 Temperature/Rainfall Annual Trends Trend in Ohio has been for warming from 1976 to recentlyTrend in Rainfall has been for increased rainfall from 1976 to recentlyMuch of the increase has been in late summer through autumn
4 Temperature/Rainfall Winter Trends Most significant warming has occurred in the winter seasonOnly minor increases in winter precipitation
5 Temperature/Rainfall Spring Trends Some warming in spring in OhioOnly slight increase in peak flood season rains
6 Temperature/Rainfall Summer Trends Little change in overall summer temperaturesSome increase in summer rainfall
7 Temperature/Rainfall Autumn Trends No change in autumn temperaturesMost significant increase have come in fall low flow season and harvest season
8 Temperature/Rainfall Autumn Trends Ohio fits composite of United States generallyGreatest warming in cool seasonGreatest increase in rainfall in autumn
9 Climate Trends in Hydrology Most trends are up especially from Deep South to Ohio Valley and Northeast.For Ohio, streamflows trends are up in 2-3 of the 4 seasons for minimum and median flows, especially autumn and late summerLittle change to all seasons in Ohio for maximum flowsUSGS Median Daily FlowsJust as temperatures and rainfall has been increasing across much of the U.S. the last 20 years, so too are streamflows. All categories are showing increases except the peak category which has seen a small decline. Regionally, most areas have increased but some have seen decreases.USGS Maximum Daily FlowsCredit: USGS
10 Cyclone Frequency Trends and Risk Natural variability in the system does account for some of the change, climate system is always changing, but we can’t explain all the change through natural processes1900 to 1950s was very active then less active period from 1960s to 1990sWe have now returned to a more active period with INCREASED RISK!
11 Climate Impacts on Ohio – La Nina Risk La Nina is the cooling of the eastern Pacific Ocean waters near the equatorThunderstorms in the western Pacific Ocean create downstream impacts into North AmericaCommonly wet in Ohio ValleyLa Nina is the cooling of the eastern Pacific Ocean equatorial waters shifting climate patterns and favoring wet weather in Ohio Valley and Kentucky.
12 Climate Impacts on Ohio – La Nina Risk Typically La Nina events have their best relationship during the winter and early springThe stronger the La Nina the better the relationshipHeavy rain along the Ohio River and adjacent areas is common
13 Climate Impacts on Ohio – El Nino Risk Typically El Nino events have their best relationship during the winter and early springThe stronger the El Nino the better the relationshipIt tends to be drier in Ohio
14 Climate Impacts on Ohio – NAO Risk North Atlantic Oscillation – relationship between low pressure near Greenland and high pressure in the AtlanticPositive phase tends to be warm and wet wintersNegative phase is colder, not as wet but snowierNAO has been more negative since early 2000sCredit: Columbia University
15 Climate Impacts on Ohio – NAO Risk Typically late winter and spring are wet with a positive NAOTypically late winter and spring are drier with a negative NAOHard to predict NAO past 2-4 weeks but climate models are getting better
16 2011 Rainfall – La Nina, NAO Risk There was a significant La Nina in early 2011The risk was > 1.5 times the normal for extreme rainfall events in the big La Nina eventsNorth Atlantic Oscillation switched from negative (colder/dry) phase in winter to positive (warmer/wet phase in springMany other reasons too as climate/weather is quite complexNorth Atlantic OscillationMuch weaker La Nina this winter means more influence by other climate factors like NAO.
17 Current NAO Strong Negative NAO fall and early winter 2010/2011 Strong Positive NAO fall and early winter 2011/2012Generally staying neutral to positive for rest of January supportingIf NAO stays positive it supports warmer weather through spring then near normal for summer still warmer in western corn belt
18 Climate Impacts on Ohio - Example NAO a FactorPositive NAO at least a contributing factor in warm weather in the East.
19 Ohio Corn Production Historical Yield Data, 1930-2007
20 Climate Impacts on Ohio - Example When NAO is negative, corn yields 10% below normal in OhioWhen NAO is positive, corn yields up 8% above normal in OhioNAO does change over time and is influenced by many factorsResearch: Joint Ohio State University and NOAA/NWS/Ohio River Forecast Center
21 Climate Impacts on Ohio - Example Crop yields fall typically 10-12% below normal when a La Nina or El Nino event occurs in the Pacific Ocean.More fluctuations in our climate will yield greater fluctuations in ENSO which will have an impact on Ohio agricultureResearch: Joint Ohio State University and NOAA/NWS/Ohio River Forecast Center
22 U.S. Climate Forecasting System Temperatures Warm winter linger into spring with temperatures trending to normal by later spring and summer
23 U.S. Climate Forecasting System Rainfall Wet winter lingers into part of spring then turning drier than normal by June and summer
24 Japan Climate Forecasting System WinterSpringSummerGoal from climate models is can we gather an overall risk. Not from individual events!
25 Positive NAONAOWinterPDOSpringLa NinaSummerNAO forecast to remain positive, La Nina to end, PDO to remain negative. Look for trends and need to know biases
27 Water Resources Outlooks Subscribe to the Ohio River Forecast Center Water Resources OutlookMonthly Outlook talking about flood and drought risk and rainfall and temperature risksProbability mapsWebsite:Subscribe:Discussion:
28 Summary Climate System is complex (no silver bullet) ENSO and NAO impact our weather, more so when events are strongMany other climate regimes impact the weather as well2012 will be different than 2011,likely fewer extreme eventsIt is all about risk management! What is the risk of events occurring!The risk appears to shift from active to inactive from spring into summer.
29 SummaryEven though risk for extreme events may be less overall in 2012 than 2011, “RISK” will be elevated for at least the next years overall.
30 Questions! James.Noel@noaa.gov NOAA/NWS/Ohio River Forecast Center Service Coordination HydrologistTHANKS!