Afternoon heating with a passing large upper level disturbance produced a thunderstorm that spawned a brief, weak tornado with no damage.
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The episode as NWS DVN wrote it up.
Afternoon heating with a passing large upper level disturbance produced a thunderstorm that spawned a brief, weak tornado with no damage.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Quad Cities, IA wrote its last area forecast discussion before the first event at May 23, 1:25 PM CST, 27 minutes earlier.
Area Forecast Discussion National Weather Service Quad Cities IA IL 225 PM CDT Tue May 23 2017 .SYNOPSIS... Issued at 224 PM CDT Tue May 23 2017 Showers have developed across the eastern and western CWA this afternoon as an upper level low slowly lumbers south. A vort max at H5 along with a weak surface front from Freeeport to Galesburg led to heavier rain showers across the far east. To the west, diurnal heating along with the upper level low has led to the development of isolated rain showers. This low, as it slowly lumbers out of the area will drive the short term weather. && .SHORT TERM...(This Evening through Wednesday) ISSUED AT 224 PM CDT Tue May 23 2017 Two main forecast concerns for the short term. The first, temperatures tomorrow as the upper level low will likely keep the area cooler than guidance. The other, the chance for rain tonight and into tomorrow associated with the upper low. Current forecast is for the heavier more persistent rain to be associated with the cold front as it slides to the east. As far as temperatures go, the MOS based guidance seems to be to high and the gridded guidance seems to be too broad brushed across the area. The current Canadian model appears to have nailed the temps for this afternoon. As a result have used the CMC blended with the Superblend for overnight lows and tomorrows highs. If we can break out in decent sun, we could see higher temps than currently forecast. As far as the precip goes, if you are follower of synoptic models, expect precip across the area. If you like the CAMs we will see widely scattered showers tomorrow afternoon across the area. Inclination is to go with the CAMs as the overall forcing will be mesoscale in nature. As a result, POPs decrease from west to east tomorrow as the low pulls out. .LONG TERM...(Wednesday Night through Tuesday) ISSUED AT 224 PM CDT Tue May 23 2017 The overall large scale picture indicates an unsettled weather pattern with temperatures at or below normal through the end of the month. Rain will end from west to east Wednesday evening with most areas being dry after midnight. The better chances for rain look to be east of the Mississippi. Dry conditions are expected on Thursday with temperatures in the lower 70s, which is slightly below normal. However, the proximity of the upper low over the Great Lakes raises questions regarding the amount of cloud cover across the area. If there are more clouds than expected, then temperatures may remain in the 60s for parts of the area. Thursday night into Friday the next storm system approaches from the Plains. Spotty rain will develop or move into the area Thursday night with a more widespread rain on Friday. Based on what the models are suggesting, the south half of the area has the better chance for rain. Temperatures should be near normal on Friday. Friday night on... The global models have the next storm system passing to the south of the area Friday night into Saturday night. However, the models disagree on the overall timing. As a result, the model consensus has slight chance to chance pops east of the Mississippi Friday night, chance pops across the entire area on Saturday, and slight chance to chance pops across the eastern two thirds of the area Saturday night. Depending upon the model solution, late Friday night and possibly Saturday morning might be dry. Sunday through Tuesday, the models diverge on their respective solutions. There is loose agreement that the next upper low will slowly drop into the Midwest and the Great Lakes. However, each model has a different timing, track, and strength of the upper low. As a result of these differences, the model consensus has slight chance pops Sunday/Sunday night, chance pops Monday, slight chance pops Monday night, and chance pops on Tuesday. Depending upon the timing and track of the upper low, the possibility does exist that Sunday/Sunday night may end up being dry. There may or may not be a period of dry weather late Monday night and Tuesday morning. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon) ISSUED AT 1243 PM CDT Tue May 23 2017 MVFR to VFR conditions today across the area have the potential to turn into IFR and LIFR overnight as low pressure slowly moves across the area. Flying conditions should generally improve in the next 2 to 6 hours across the area with CIGs starting to reach VFR heights. Later tonight CIGs could drop to IFR and LIFR. Low confidence at this time has precluded them from being adding at this time. && .HYDROLOGY... Issued at 224 PM CDT Tue May 23 2017 Heavy rain fell across Minnesota and Wisconsin last week and will move down the Mississippi river over the next 14 days. Many tributary rivers are running higher than normal. An unsettled weather pattern will be seen across the Midwest through the end of the month with several chances for rain. The additional rainfall may result in changes to river forecasts so one should not lock onto a specific crest forecast. Mississippi River... Flood warnings are now in effect for LD11 and Dubuque. Flood warning continue for Gladstone and Burlington. The river is expected to rise at all locations over the next 7 to 10 days. Flood watches have been issued for the Mississippi river from LD13 south through Keithsburg with the river rising over the next 14 days. Iowa River... The Iowa river at Marengo is now expected to crest just below flood stage. Any additional rainfall across the basin in the next 7 days may push the river above flood stage. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && SYNOPSIS...Gibbs SHORT TERM...Gibbs LONG TERM...08 AVIATION...Gibbs HYDROLOGY...08
Hazardous Weather Outlook National Weather Service Quad Cities IA IL 419 AM CDT Tue May 23 2017 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-240930- Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson- Cedar-Clinton-Muscatine-Scott-Keokuk-Washington-Louisa-Jefferson- Henry IA-Des Moines-Van Buren-Lee-Jo Daviess-Stephenson-Carroll- Whiteside-Rock Island-Henry IL-Bureau-Putnam-Mercer-Henderson- Warren-Hancock-McDonough-Scotland-Clark- 419 AM CDT Tue May 23 2017 This Hazardous Weather Outlook is for portions of north central Illinois...northwest Illinois...west central Illinois...east central Iowa...northeast Iowa...southeast Iowa and northeast Missouri. .DAY ONE...TODAY AND TONIGHT There is a slight chance of thunderstorms today. The main threat is lightning, with a secondary threat of small hail. The Mississippi River is experiencing flooding, and other area rivers are on the rise. Please see the latest Flood Statements and Flood Warnings for details. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY There is a slight chance of thunderstorms on Wednesday. The next chance for storms will be Friday and Saturday as a warm front sets up over the area. It is too early to determine the severe weather potential with these late-week storms. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated this afternoon, and will not be needed tonight.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Quad Cities IA/IL
230 PM CDT TUE MAY 23 2017
IAZ041-042-ILZ001-232230-
Jo Daviess-Delaware-Dubuque-
230 PM CDT TUE MAY 23 2017
...Funnel clouds will affect Jo Daviess...northwestern Carroll...
northeastern Jackson...eastern Buchanan...Dubuque and Delaware
Counties this afternoon...
Funnel clouds of this nature are short lived and rarely touch the
ground. However, if you notice one approaching the ground, move
indoors to a place of safety.
The National Weather Service will continue to closely monitor the
situation. Please forward reports of funnel cloud sightings to the
nearest law enforcement agency for relay to the National Weather
Service.
LAT...LON 4264 9071 4251 9064 4251 8993 4220 8992
4219 9032 4225 9042 4233 9042 4238 9047
4238 9066 4230 9067 4230 9160 4264 9161
4265 9090 4267 9089
TIME...MOT...LOC 1929Z 267DEG 0KT 4254 9146
GibbsSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Quad Cities IA/IL
234 PM CDT TUE MAY 23 2017
IAZ041-042-ILZ001-232230-
Jo Daviess-Delaware-Dubuque-
234 PM CDT TUE MAY 23 2017
...Funnel clouds will affect Jo Daviess...Dubuque and Delaware
Counties...
Funnel clouds of this nature are short lived and rarely touch the
ground. However, if you notice one approaching the ground, move
indoors to a place of safety.
The National Weather Service will continue to closely monitor the
situation. Please forward reports of funnel cloud sightings to the
nearest law enforcement agency for relay to the National Weather
Service.
LAT...LON 4264 9071 4251 9064 4251 8993 4220 8992
4219 9032 4225 9042 4233 9042 4238 9047
4238 9066 4230 9067 4230 9160 4264 9161
4265 9090 4267 9089
TIME...MOT...LOC 1932Z 267DEG 0KT 4254 9146
GibbsThe Quad Cities radar (KDVN), 48 km away, was scanning. The volume nearest the first event began at 19:54 UTC.
1 tornado. Local standard time, as filed.
A brief EF-0 tornado touched down in open farmland as observed by 2 eyewitnesses. They stated they slowed down as it crossed the road with no damage observed by survey team.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2017Every state in 2017This day in weather historyThe tornado archive for Illinois, 2017Warnings in Illinois, May 2017
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 703396.