On This Date in Iowa Weather History: Dunkerton, Iowa F3 Tornado – May 11, 2000

On May 11, 2000, severe thunderstorms produced large hail and at least seven tornadoes across northeastern Iowa including one that killed one person and injured 25 others as it produced F3 damage near Dunkerton, Iowa.  This would be affecting some of the same areas that would be struck by the EF5 Parkersburg tornado eight years later. The largest reported hail stones were the size of baseballs, falling near Dorchester in Allamakee County.

You can find more information regarding this event from the following sources:

http://www.silverliningtours.com/may-11th-2000-dunkerton-iowa-f3-tornado/

http://cbs2iowa.com/news/local/15-years-since-dunkerton-tornado

http://wcfcourier.com/news/top_story/five-years-later-dunkerton-remembers-tornado/article_c812a6b7-5378-57f8-b14e-f312e62955d9.html

 

 

Spring 2017 Weather Whisper Newsletter Navigation

Climate

February 2017 Warmth at Des Moines – By Jim Lee, Meteorologist

February 2017 Warmth at Waterloo – By Jim Lee, Meteorologist

Spring and Summer Outlooks for Iowa – 2017 – By Allan Curtis, Meteorologist Intern

Outreach and Education

Spotter Training – Spring 2017

Spring Fire Weather Update – by Frank Boksa, Meteorologist

NWS Des Moines Participates in the Girls in Science Festival – By Mindy Beerends, Senior Meteorologist

NWS Des Moines Decision Support Services – By Kenny Podrazik, Meteorologist

Cooperative Observer Awards

Science and Technology

New Weather Satellite Will Improve Forecasting and Warnings – By Andrew Ansorge, Meteorologist

 

NWS Des Moines Decision Support Services

The National Weather Service continues to provide decision support services (DSS) for specific events and/or incidents to partners and stakeholders throughout the year. Most DSS provided is for scheduled events such as county fairs, races, parades, concerts, and even RAGBRAI. Occasionally, the NWS will be asked upon to provide DSS for emergency incidents including one recent event that occurred in Graettinger, Iowa (Palo Alto County) when a train derailed on the morning of March 10, 2017.  A total of 27 cars where involved with the train derailment in which a few were loaded with alcohol and was unfortunately set ablaze (See image below).   The Palo Alto Emergency Management requested daily DSS briefings which included highlights of upcoming weather, hourly forecast graph, a detailed 5-day text forecast, and resources (See Figure 1).   The briefings finally ceased by Wednesday March 15th and this incident is just one of several examples on the DSS that the NWS provides to their partners. 
 
NWS Decision Support Services Include (but not limited to): 
  • Weather briefings provided at designated times and through requested formats including phone calls, emails, video conferences and on-site deployments
  • NWS maintains a constant weather watch for the event or incident
  • If hazardous weather is imminent, the NWS will contact the provided point of contact(s)
  • Support provided for your requested impact and decision making thresholds
  • Location specific situational awareness webpage
Last summer, the NWS deployed a new DSS Calendar Tool to aid in the NWS Des Moines partner support.   Requests can be made by NWS partners and once a request is received and details of the DSS is finalized, then the event/incident is listed in the DSS Calendar.  The NWS Des Moines also has several Decision Support Pages available for anyone to use:  NWS Des Moines Decision Support Page.  The DSS varies from severewinter, fire weather and flooding. Radar, satellite, current watches and warnings, webcams, road conditions, and the latest observations are all available on the aforementioned links.  
KCAU-TV/Nexstar Media Group

KCAU-TV/Nexstar Media Group

DSS-trainderailment

Figure 1: Example of the decision support services provided to the Palo Alto Emergency Management for the Graettinger, Iowa Train Derailment in March 2017.

Blog post by Kenny Podrazik, Meteorologist
 

 

Spring Fire Weather Update

The recent stretch of unseasonably warm and dry weather forced a slightly earlier start to the 2017 fire weather season for much of Iowa.  Fire weather planning forecasts and a daily Grassland Fire Danger map are displayed on the fire weather page of our website as is the current Annual Operating Plan. 

Late last fall there was a re-design of the spot forecast request page with a few additional tweaks being made over the winter.  The spot request page is Google based now and overall is easier to use than the old page. However, there are some things to keep in mind.  Since the spot request page is only used by government agencies and those with government contracts, most of these changes will not impact the majority of customers that use the fire weather page.  Training on the new spot page is provided by clicking on the link within the fire weather page.

spotrequest

In other fire weather news, there have been studies done on the Grassland Fire Danger Index in particular, how it relates to when we are issuing Red Flag Warnings based on fuels and meteorological parameters.  There was confirmation that the ranges for the categories, in particular the very high and extreme categories, needed some adjusting for the Plains.  Changes were made based on where tall grass, short grass and mixed grass prairies exists and a proposal is being worked on to not only adopt these changes but to have all central region offices run the Grassland Fire Danger Index for their areas and see if this is a better tool at determining a grassland danger threat.

To view the fire weather forecasts, fire weather planning tools and the 2017 Annual Operating, please visit the National Weather Service website at: http://www.weather.gov/dmx/fire

Blog post by Frank Boksa, Meteorologist

February 2017 Warmth at Des Moines

February of 2017 was remarkably warm across Iowa, including at Des Moines where it was the warmest February on record and continued a streak of 18 consecutive months in which the average temperature has been above normal, dating back to September of 2015. Several daily records were established for warm temperatures in February, including maximum temperature records on the 17th (75°F), 19th (73°F), 21st (68°F) and 22nd (73°F), and a warm minimum temperature record on the 22nd (47°F). During the 28 days of February there were only 4 days with an average temperature below normal, while there were 16 days that were 10+ degrees above normal and 8 days that were 20+ degrees above normal. Here is where the month stacked up in various Des Moines records (going back to 1879):

Warmest February’s on record

  1. 39.2°F (2017)
  2. 38.1°F (1930)
  3. 37.7°F (1954)
  4. 36.9°F (1931)
  5. 36.4°F (2000)

Warmest February days on record

  1. 78°F (2/24/1930)
  2. 75°F (2/17/2017), 75°F (2/15/1921)
  3. 73°F (2/22/2017), 73°F (2/19/2017), 73°F (2/29/1972)

Most 70+ degree days in February

  1. 3 (2017)
  2. 2 (1930)
    (All other years 1 or 0)

Most 60+ degree days in February

  1. 8 (2017)
  2. 7 (1981, 1930)
  3. 6 (2000)
  4. 5 (1999, 1932)

DesMoinesFeb2017Temps

Blog post by Jim Lee, Meteorologist

New Weather Satellite Will Improve Forecasting and Warnings

On November 19, 2016, the GOES-R weather satellite was successfully launched into space from Cape Canaveral, FL. After reaching geostationary orbit a little over a week later, GOES-R was renamed GOES-16.  While GOES-16 is still undergoing testing, once fully operationally later this year it will provide your National Weather Service meteorologists along with many other users with faster updates, higher resolution images, and more (spectral) channels than any GOES satellite ever before. This satellite will also provide continuous monitoring of lightning activity. It’s essentially like going from standard definition, black and white television to high definition, color television.

GOES-16 will boast 5 times faster updates. With the current satellites, images are typically received every 15 minutes. With GOES-16, images will be received every 5 minutes and during high-impact weather they can be received every minute or even every 30 seconds! This means that we’ll be able to view thunderstorms in near real-time as they develop and before they are even detected on radar.

Images from GOES-16 will be high resolution. The current GOES satellites provide 1 kilometer visible images with infrared and water vapor images at 4 kilometer. With GOES-16, visible image will be at 0.5 kilometers with infrared and water vapor images at 2 kilometers. Along with faster updates, this means we’ll view finer features important to forecasting and warning operations.

Finally, GOES-16 will have 3 times the number of spectral channels. Basically, a spectral channel is able to ‘see’ different features better than another spectral channel. For example, one of the new satellite channels can differentiate between land and water while another channel will be able to monitor high-level cirrus clouds.

What this all means locally to the public and the partners we serve is increased lead time for thunderstorm and tornado warnings, enhanced general and commercial aviation forecasts, better detection of grass and cropland fires, and improved fog formation and dissipation forecasts.


Check out the high resolution image comparing GOES-13 to GOES-16 imagery: https://www.nesdis.noaa.gov/sites/default/files/assets/images/goes_16_and_goes_13_comparison_from_the_same_day_Jan_15_2017_high_res.jpg

Blog post by: Andrew Ansorge, Meteorologist

Spring and Summer Outlooks for Iowa – 2017

Introduction

Now that we’re finally exiting the winter months and well on our way to spring, you’re probably wondering what might be in store for the remainder of spring and summer.  While seasonal forecasting is far from perfect, we can often times get a feel for what may occur based on teleconnections.  What is a teleconnection you ask?  Good question.  In atmospheric sciences, teleconnections are anomalies that have shown a relation to each other.  A great example of a teleconnection that many have heard about is El Nino, or more properly, El Nino-Southern Oscillation (ENSO).  For those that have seen previous seasonal outlooks from our blog, you are probably already familiar with what ENSO is.  For those that are not, take a peek below.

ENSO refers to a phenomenon that exists along the equatorial Pacific Ocean.  It is categorized as El Nino or La Nina depending on the type of anomaly or Neutral if there is no anomaly or a very weak one.  More specifically, El Nino is characterized by anomalously warm seas surface temperatures that propagate eastward towards the South American coast.  Conversely, La Nina is characterized by anomalously cool sea surface temperatures off of the coast of South America that propagate into the central Pacific Ocean.  The oscillation between the two is ENSO.  Do determine whether or not El Nino or La Nina conditions exist, the Oceanic Nino Index (ONI) is used.  The ONI is a measure of above and below normal sea surface temperatures within specific regions of the equatorial Pacific.  For an event to be declared, 5 consecutive over-lapping 3 month periods must be anomalous one way or another by 0.5 deg C or more.  El Nino would be for positive anomalies and La Nina for negative ones.  Anything that does not meet the 5 consecutive period criteria or is within +/- 0.5 deg C is declared Neutral.  Note the difference between conditions and event.  Conditions exist during any 3 month averaging period, while an event takes the 5 consecutive over-lapping 3 month periods mentioned previously. 

At this point, you may be wondering what Pacific Ocean sea surface temperatures have to do with weather in the in the United States, let alone Iowa.  The atmosphere is constantly in flux, responding to various inputs such as ENSO conditions in the Equatorial Pacific in an attempt to reach equilibrium.  Phenomena that last long periods of time and occur regularly can affect atmospheric conditions in ways that lead to tendencies in other areas, teleconnections.  A number of phenomena across the globe have been researched and found to correlate to weather patterns in other locations across the globe, and ENSO is the most researched and well known teleconnection for the United States.  We’ll proceed to take a look at the tendencies for forecasted neutral to El Nino conditions in Iowa for the upcoming Spring and Summer seasons.

For more detailed information about El Nino and La Nina, atmospheric conditions, thresholds, U.S. impacts, global impacts, and more, check out: https://www.climate.gov/enso

For more detailed information about the Oceanic Nino Index, check out: http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml

Spring

Currently, Neutral conditions exist within the Nino 3.4 region, having just come out of relatively weak La Nina conditions through winter.  Official ENSO probabilistic forecasts indicate a likely transition towards El Nino conditions within the Nino 3.4 region as spring and summer progresses.  Though focusing on Spring alone, forecasts heavily favor Neutral conditions, which makes sense in the short term considering the region just came out of La Nina conditions.

(Image 1: Official probabilistic ENSO Forecast from the Climate Prediction Center and International Research Institute for Climate and Society)

Noting the heavy lean to neutral conditions within the forecast, we will focus strictly on historical Neutral events for Iowa and surrounding areas during Spring.  It should be noted that with conditions freshly coming off of a La Nina event, atmospheric response, especially as it pertains to the United States, may be in transition throughout Spring as neutral conditions set in.  Historically, temperatures during Neutral conditions have leaned on the cooler side of average for the Upper Midwest and Upper Mississippi Valley’s with Iowa on the southern edge and with only minimal cool departures (Image 2: Temperature Anomalies (F) for previous Neutral events during the Spring).  The analysis for precipitation points towards above average precipitation throughout much of the Mississippi Valley and Upper Midwest, including the entire state of Iowa.  Once again, though, the state finds itself on the lower end of the departures (Image 3: Precipitation anomalies (in) for previous Neutral events during the Spring). For both temperature and precipitation, the largest departures are well away from Iowa, predominantly centered on the south and west. 

Comparatively we’ll take a quick look at the official Climate Prediction Center (CPC) outlooks for Spring as well.  As it pertains to temperatures, the CPC suggests a slightly better opportunity for above normal temperatures versus normal or below normal through Iowa (Image 4: Spring temperature outlook from the Climate Prediction Center).  Looking at precipitation, the CPC indicates a slightly better opportunity for above normal precipitation over northern Iowa, while central and southern Iowa has equal chances for above, below, or normal precipitation (Image 5: Spring precipitation outlook from the Climate Prediction Center).  While the CPC precipitation forecast roughly resembles a nod towards the Neutral analysis, temperatures do not.  Which possibly indicates lingering La Nina influence as the atmosphere continues to respond to incoming Neutral conditions or the influence of other phenomena and atmospheric patterns being taken into consideration.

Summer

Now with summer a couple of months away yet, a bit more uncertainty comes into play for the ENSO forecasts.  Recall the forecast at the beginning showed increasing likelihood of El Nino conditions setting in, but hovered around 40-50%, with Neutral conditions taking up much of the remaining likelihood.  With that in mind, we’ll take a quick look at what both Neutral and El Nino conditions have resulted in historically.  

Examining Neutral conditions first, there is no strong tendency for above or below average precipitation within the state, let alone the surrounding states (Image 6: Precipitation anomalies (in) for previous Neutral events during the Summer). Conversely temperatures do show a tendency to be above average throughout most of Iowa and much of the United States for that matter (Image 7: Temperature anomalies (F) for previous Neutral events during the Summer).   The best tendencies for precipitation reside through the Appalachian region and for temperature the southwest US.  

On the El Nino side of the equation, precipitation tendencies show up within the state and surrounding areas, however they are a bit of a mixed bag of both above and below average (Image 8: Precipitation anomalies (in) for previous El Nino events during the Summer).  On the temperature side, history favors below average temperatures throughout Iowa and surrounding areas, which opposite that of historical Neutral conditions (Image 9: Temperature anomalies (F) for previous El Nino events during the Summer).  In the El Nino case, it is hard to pinpoint the best tendency for precipitation within the United States given the mixed responses, whereas the northern Great Lakes region shows the best tendency for temperatures.   

Once again to give some perspective, we’ll take a quick look at the Climate Prediction Center forecast for the summer months.  At first glance, both the precipitation and temperature summer outlooks from the Climate Prediction Center loosely resemble the Neutral conditions depicted above versus the El Nino ones (Image 10: Spring precipitation outlook from the Climate Prediction Center) (Image 11: Spring temperature outlook from the Climate Prediction Center).  Recall once again that the atmosphere takes time to respond to changes such as ENSO.  Should El Nino make an appearance it will have to traverse through Neutral conditions first, remember we just came out of La Nina, on its way to El Nino.  So void of other influences, it would make a degree of sense that the atmosphere may still be responding to Neutral conditions even if El Nino creeps in.  Of course, ENSO is not the only teleconnection that influences our weather conditions.  Others that have been and are continuing to be researched include the North Atlantic Oscillation, the Madden-Julien Oscillation, the Pacific Decadal Oscillation, and more.  In future editions we may explore how some of these other teleconnections can affect Iowa and the United States.  Until then, we will see how spring and summer play out and whether or not ENSO tendencies appear.

Blog post by: Allan Curtis, Meteorologist Intern

Spotter Training – Spring 2017

Severe Storm Spotting classes are underway this spring.  Classes are available for central Iowa communities through the end of April and we hope you’re able to find one near you.  You can find a listing of upcoming classes here: 2017 Spotter Training Schedule.  If you can’t make a class, you can find plenty of storm spotting resources on our homepage. Below is a quick review on the importance of severe storm spotting and the different avenues to report severe weather to the National Weather Service. 

Reporting Severe Weather

Reporting severe weather is essential! Regardless of the reporting method, each report must include the time & location of the event (and direction looking if applicable). Pictures tell a thousand words, but remember to include when and where the weather occurred! If you do send photos, please let us know if you grant permission for us to use them in future spotter talks and outreach presentations.


How to Report:

Online: Use our online weather reporting form! For reporting tornadoes, please use our 1-800-SKYWARN telephone line.

Email: dmx.spotterreport@noaa.gov – A great way to include pictures & video.

Text Message: (515)-240-5515 – Text us reports and your phone photos/videos.

Telephone: 1-(800)-SKYWARN – Must have been through severe weather spotter training and belong to a spotter network to use this line! Refer to materials received during spotter training.

Facebook: Visit our Facebook page and post a severe weather report to our wall.

Twitter – Tweet us your reports by including the #iawx or #nwsdmx hashtag or send them directly to @NWSDesMoines.

Amateur Radio – The National Weather Service group amateur radio call-sign is KØDMX.

February 2017 Warmth at Waterloo

February of 2017 was remarkably warm across Iowa, including at Waterloo where it was the 4th-warmest February on record (going back to 1895). Daily record maximum temperatures were established on the 17th (69°F), 19th (67°F) and 22nd (69°F). During the 28 days of February there were only 5 days with an average temperature below normal, while there were 15 days that were 10+ degrees above normal and 5 days that were 20+ above normal. Here is where the month stacked up in various Waterloo records:

Warmest Februarys on record
1. 35.2°F (1954)
2. 34.9°F (1931)
3. 34.4°F (1998)
4. 33.6°F (2017)
5. 33.0°F (1930)

Warmest February days on record
1. 71°F (2/15/1921)
2. 69°F (2/22/2017)
    69°F (2/17/2017)
4. 67°F (2/19/2017)
5. 66°F (2/17/1981)
    66°F (2/25/2000)

Most 60°F+ degree days in February
1. 7 (1930)
2. 5 (2017)
3. 4 (1981)
4. 3 (2000)
5. 2 (1921)

WaterlooFeb2017Temps

 

Blog post by Jim Lee, Meteorologist