National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Iowa Weather & Flood OutlookIowa Weather & Flood OutlookIowa Weather & Flood OutlookIowa Weather & Flood Outlook
February 10, 2010February 10, 2010
Jeff Johnson & Jeff ZoggJeff Johnson & Jeff Zogg
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
TopicsTopicsTopicsTopics
• Outlook at-a-glanceOutlook at-a-glance• DefinitionsDefinitions• Current conditionsCurrent conditions• Latest spring food outlookLatest spring food outlook• QuestionsQuestions
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Where We Stand Where We Stand Where We Stand Where We Stand
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Current Weather Situation Current Weather Situation Current Weather Situation Current Weather Situation
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Weather Map 6 AM Thursday, February 11th Weather Map 6 AM Thursday, February 11th Weather Map 6 AM Thursday, February 11th Weather Map 6 AM Thursday, February 11th
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Weather Map 6 AM Friday, February 12th Weather Map 6 AM Friday, February 12th Weather Map 6 AM Friday, February 12th Weather Map 6 AM Friday, February 12th
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Weather Map 6 AM Saturday, February 13th Weather Map 6 AM Saturday, February 13th Weather Map 6 AM Saturday, February 13th Weather Map 6 AM Saturday, February 13th
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Weather Map 6 AM Sunday, February 14th Weather Map 6 AM Sunday, February 14th Weather Map 6 AM Sunday, February 14th Weather Map 6 AM Sunday, February 14th
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Precipitation forecast for the weekend Precipitation forecast for the weekend Precipitation forecast for the weekend Precipitation forecast for the weekend
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
The Seven Day Forecast for Des MoinesThe Seven Day Forecast for Des MoinesThe Seven Day Forecast for Des MoinesThe Seven Day Forecast for Des Moines
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
How About Days 8-14?How About Days 8-14?How About Days 8-14?How About Days 8-14?
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Upcoming Events! Upcoming Events! Upcoming Events! Upcoming Events!
Spotter Training Starts Next Week Spotter Training Starts Next Week Schedule at: Schedule at:
www.weather.gov/desmoines/?n=spotterinfo www.weather.gov/desmoines/?n=spotterinfo
Spotter Training Starts Next Week Spotter Training Starts Next Week Schedule at: Schedule at:
www.weather.gov/desmoines/?n=spotterinfo www.weather.gov/desmoines/?n=spotterinfo
Severe Weather Awareness Week Severe Weather Awareness Week April 5-9 April 5-9
Test tornado drill Test tornado drill Wednesday, April 8Wednesday, April 8thth at 10:00 AM at 10:00 AM
Severe Weather Awareness Week Severe Weather Awareness Week April 5-9 April 5-9
Test tornado drill Test tornado drill Wednesday, April 8Wednesday, April 8thth at 10:00 AM at 10:00 AM
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Outlook at-a-glanceOutlook at-a-glanceOutlook at-a-glanceOutlook at-a-glance
• High risk of significant floodingHigh risk of significant flooding in northwest Iowa. in northwest Iowa.– Also concerned about flooding in southeast Iowa—Mississippi Also concerned about flooding in southeast Iowa—Mississippi
River and its tributaries.River and its tributaries.– At least near to above normal risk of flooding statewide.At least near to above normal risk of flooding statewide.
• Above normal risk of Above normal risk of flooding from ice jams.flooding from ice jams.• Higher than normal risk of flooding also in areas that Higher than normal risk of flooding also in areas that
have have little to no snow cover.little to no snow cover.• The flooding potential will be more sensitive than The flooding potential will be more sensitive than
normalnormal to the occurrence and timing of weather events to the occurrence and timing of weather events such as rapid warm ups and heavy precipitation.such as rapid warm ups and heavy precipitation.
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
DefinitionsDefinitionsDefinitionsDefinitions
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
DefinitionsDefinitionsDefinitionsDefinitions
• Stage / Gage heightStage / Gage height– The level of the water surface of a stream above an The level of the water surface of a stream above an
established datum at a given location. The established datum established datum at a given location. The established datum may be a local elevation or sea level.may be a local elevation or sea level.
• ReachReach– A section of stream between an upstream and downstream A section of stream between an upstream and downstream
location, for which the stage or flow measured at a point location, for which the stage or flow measured at a point somewhere along the section (e.g., gaging station or forecast somewhere along the section (e.g., gaging station or forecast point) is representative of conditions in that section of river point) is representative of conditions in that section of river or stream.or stream.
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
DefinitionsDefinitionsDefinitionsDefinitions
• Bankfull stageBankfull stage– An established gage height at a given location, above which a An established gage height at a given location, above which a
rise in water surface will cause the river or stream to rise in water surface will cause the river or stream to overflow the river bank somewhere in the corresponding overflow the river bank somewhere in the corresponding reach.reach.
• Flood stageFlood stage– An established gage height for a given location at which a rise An established gage height for a given location at which a rise
in water surface level begins to create a hazard to lives, in water surface level begins to create a hazard to lives, property or commerce. The issuance of flood (or in some property or commerce. The issuance of flood (or in some cases flash flood) warnings is linked to flood stage. Not cases flash flood) warnings is linked to flood stage. Not necessarily the same as bankfull stage.necessarily the same as bankfull stage.
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
DefinitionsDefinitionsDefinitionsDefinitions
• Minor floodingMinor flooding– Minimal or no property damage, but possibly some public Minimal or no property damage, but possibly some public
threat.threat.• Moderate floodingModerate flooding
– Some inundation of structures and roads near stream. Some Some inundation of structures and roads near stream. Some evacuations of people and/or transfer of property to higher evacuations of people and/or transfer of property to higher elevations.elevations.
• Major floodingMajor flooding– Extensive inundation of structures and roads. Significant Extensive inundation of structures and roads. Significant
evacuations of people and/or transfer of property to higher evacuations of people and/or transfer of property to higher elevations.elevations.
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
DefinitionsDefinitionsDefinitionsDefinitions
• Record floodingRecord flooding– Flooding which equals or exceeds the Flooding which equals or exceeds the
highest stage or discharge observed at highest stage or discharge observed at a given site during the period of record a given site during the period of record keeping. The highest stage on record is keeping. The highest stage on record is not necessarily above the other three not necessarily above the other three flood categories – it may be within any flood categories – it may be within any of them or even less than the lowest.of them or even less than the lowest.
Stage – flood category Stage – flood category relationshiprelationship
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Current conditionsCurrent conditionsCurrent conditionsCurrent conditions
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Winter average temperaturesWinter average temperaturesWinter average temperaturesWinter average temperatures
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Winter precipitationWinter precipitationWinter precipitationWinter precipitation
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Winter snowfallWinter snowfallWinter snowfallWinter snowfall
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Snow pack—nowSnow pack—nowSnow pack—nowSnow pack—now
Snow depth—Snow depth—2/9/20102/9/2010
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Snow pack—nowSnow pack—nowSnow pack—nowSnow pack—now
Snow depth vs. normal—Snow depth vs. normal—2/9/20102/9/2010
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Snow pack—nowSnow pack—nowSnow pack—nowSnow pack—now
Snow water equivalent—Snow water equivalent—2/9/20102/9/2010
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Snow pack—historicalSnow pack—historicalSnow pack—historicalSnow pack—historical
Snow water equivalent—Snow water equivalent—2/9/20092/9/2009
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Snow pack—historicalSnow pack—historicalSnow pack—historicalSnow pack—historical
Snow water equivalent—Snow water equivalent—2/9/20082/9/2008
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Snow pack—now (repeat)Snow pack—now (repeat)Snow pack—now (repeat)Snow pack—now (repeat)
Snow water equivalent—Snow water equivalent—2/9/20102/9/2010
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Stream levels—nowStream levels—nowStream levels—nowStream levels—now
14-day average flow—14-day average flow—as of 2/8/2010as of 2/8/2010
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Stream levels—historicalStream levels—historicalStream levels—historicalStream levels—historical
14-day average flow—14-day average flow—as of 2/8/2009as of 2/8/2009
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Stream levels—historicalStream levels—historicalStream levels—historicalStream levels—historical
14-day average flow—14-day average flow—as of 2/8/2008as of 2/8/2008
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Stream levels—now (repeat)Stream levels—now (repeat)Stream levels—now (repeat)Stream levels—now (repeat)
14-day average flow—14-day average flow—as of 2/8/2010as of 2/8/2010
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Ground frostGround frostGround frostGround frost
Frost depth—Frost depth—2/9/20102/9/2010
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Soil moisture—nowSoil moisture—nowSoil moisture—nowSoil moisture—now
Percentile keyPercentile key
~1: near record low~1: near record low<10: much below normal<10: much below normal10 -24: below normal10 -24: below normal
25-75: normal25-75: normal
76-90: above normal76-90: above normal>90: much above normal>90: much above normal~99: near record high~99: near record high
Soil moisture percentiles—Soil moisture percentiles—2/8/20102/8/2010
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Soil moisture—recentSoil moisture—recentSoil moisture—recentSoil moisture—recent
Percentile keyPercentile key
~1: near record low~1: near record low<10: much below normal<10: much below normal10 -24: below normal10 -24: below normal
25-75: normal25-75: normal
76-90: above normal76-90: above normal>90: much above normal>90: much above normal~99: near record high~99: near record high
Soil moisture percentiles—Soil moisture percentiles—January 2010January 2010
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Soil moisture—recentSoil moisture—recentSoil moisture—recentSoil moisture—recent
Percentile keyPercentile key
~1: near record low~1: near record low<10: much below normal<10: much below normal10 -24: below normal10 -24: below normal
25-75: normal25-75: normal
76-90: above normal76-90: above normal>90: much above normal>90: much above normal~99: near record high~99: near record high
Soil moisture percentiles—Soil moisture percentiles—December 2009December 2009
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Latest spring flood outlookLatest spring flood outlookLatest spring flood outlookLatest spring flood outlook
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Assumptions / notesAssumptions / notesAssumptions / notesAssumptions / notes
• This outlook assumes near normal temperatures and This outlook assumes near normal temperatures and precipitation (i.e., climatology) during the outlook precipitation (i.e., climatology) during the outlook period.period.– If conditions are not near normal then the probabilities in is If conditions are not near normal then the probabilities in is
outlook may not be valid.outlook may not be valid.• For example, if above normal precipitation is expected For example, if above normal precipitation is expected
during the outlook period, then the probabilities in this during the outlook period, then the probabilities in this outlook may be too low.outlook may be too low.
– Outlook assumes near normal through late April.Outlook assumes near normal through late April.• Official temperature outlook Official temperature outlook near to above normal. near to above normal.• Official precipitation outlook Official precipitation outlook no strong trend signal. no strong trend signal.
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Assumptions / notesAssumptions / notesAssumptions / notesAssumptions / notes
• Ice jamsIce jams– Any ice jams which do occur may result in locally higher river Any ice jams which do occur may result in locally higher river
stages and rapid river rises. This outlook does not take into stages and rapid river rises. This outlook does not take into account potential flooding from ice jams. Any flooding from account potential flooding from ice jams. Any flooding from ice jams would be above and beyond the flooding potential ice jams would be above and beyond the flooding potential indicated in this outlook.indicated in this outlook.
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Temp & precip outlook through late AprilTemp & precip outlook through late AprilTemp & precip outlook through late AprilTemp & precip outlook through late April
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
El Nino—nowEl Nino—nowEl Nino—nowEl Nino—now
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
El Nino—forecastEl Nino—forecastEl Nino—forecastEl Nino—forecast
Decreasing El Nino with Decreasing El Nino with timetime
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Median (50% chance) flood categoryMedian (50% chance) flood categoryMedian (50% chance) flood categoryMedian (50% chance) flood category
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Risk of Risk of minorminor flooding floodingRisk of Risk of minorminor flooding flooding
West 1/3 of Iowa (Missouri River basin)West 1/3 of Iowa (Missouri River basin) East 2/3 of Iowa (Mississippi River basin)East 2/3 of Iowa (Mississippi River basin)
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Risk of Risk of moderatemoderate flooding floodingRisk of Risk of moderatemoderate flooding flooding
West 1/3 of Iowa (Missouri River basin)West 1/3 of Iowa (Missouri River basin) East 2/3 of Iowa (Mississippi River basin)East 2/3 of Iowa (Mississippi River basin)
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Risk of Risk of majormajor flooding floodingRisk of Risk of majormajor flooding flooding
West 1/3 of Iowa (Missouri River basin)West 1/3 of Iowa (Missouri River basin) East 2/3 of Iowa (Mississippi River basin)East 2/3 of Iowa (Mississippi River basin)
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Final thoughtsFinal thoughtsFinal thoughtsFinal thoughts
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Final thoughtsFinal thoughtsFinal thoughtsFinal thoughts
• Most homeowners’ insurance policies do not cover Most homeowners’ insurance policies do not cover flood-related losses.flood-related losses.– To cover flood-related losses, flood insurance must typically To cover flood-related losses, flood insurance must typically
be purchased. This is in addition to homeowners insurance.be purchased. This is in addition to homeowners insurance.– Disaster assistance, if it’s available, is typically a loan that you Disaster assistance, if it’s available, is typically a loan that you
must repay with interest.must repay with interest.– In most cases, flood insurance requires a 30-day waiting In most cases, flood insurance requires a 30-day waiting
period before it becomes effective.period before it becomes effective.– Visit http://www.floodsmart.gov/ for more information.Visit http://www.floodsmart.gov/ for more information.
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Final thoughtsFinal thoughtsFinal thoughtsFinal thoughts
• Will we see another “2008”?Will we see another “2008”?– A big factor in 2008 was the heavy rainfall from May-June.A big factor in 2008 was the heavy rainfall from May-June.– High-end events such as the 2008 floods typically result from High-end events such as the 2008 floods typically result from
a sequence of additive factors. While one factor by itself may a sequence of additive factors. While one factor by itself may not lead to a high-end event, the combination of factors not lead to a high-end event, the combination of factors elevates the risk of a high-end event.elevates the risk of a high-end event.
– Factors which contribute to significant flooding this spring are Factors which contribute to significant flooding this spring are lining up.lining up.
– This does NOT automatically mean that we’ll have a repeat of This does NOT automatically mean that we’ll have a repeat of 2008 though. We could luck out this spring—the flooding 2008 though. We could luck out this spring—the flooding may be less severe than our outlook indicates. But, the risk may be less severe than our outlook indicates. But, the risk of flooding is elevated so we need to watch things closely.of flooding is elevated so we need to watch things closely.
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
Final thoughtsFinal thoughtsFinal thoughtsFinal thoughts
• Spring flood outlook scheduleSpring flood outlook schedule– 1st Outlook: Friday, January 29, 2010.1st Outlook: Friday, January 29, 2010.– 2nd Outlook: Friday, February 19, 2010.2nd Outlook: Friday, February 19, 2010.– 3rd Outlook: Friday, March 5, 2010.3rd Outlook: Friday, March 5, 2010.– 4th Outlook (Optional): Friday, March 26, 2010.4th Outlook (Optional): Friday, March 26, 2010.
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
National Weather ServiceNational Weather ServiceDes Moines, IADes Moines, IA
QuestionsQuestionsQuestionsQuestions
Contact information:Contact information:[email protected] or [email protected]@noaa.gov or [email protected]
515-270-4501515-270-4501http://www.weather.gov/desmoineshttp://www.weather.gov/desmoines
Top Related