Marine Weather and Tide Forecast for Nora, IL
May 20, 2024 6:21 AM CDT (11:21 UTC) Change Location
 | Sunrise 5:30 AM Sunset 8:20 PM Moonrise 4:42 PM Moonset 2:54 AM |
Area Discussion for - Quad Cities, IA/IL
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FXUS63 KDVN 201033 AFDDVN
Area Forecast Discussion National Weather Service Quad Cities IA IL 533 AM CDT Mon May 20 2024
KEY MESSAGES
- There is a marginal risk (level 1 of 5) for severe weather today. Hail up to quarters and 60 mph winds will be the primary threats with the strongest storms if they occur.
- There is an enhanced risk (level 3 of 5) for severe weather on Tuesday. Large hail, damaging wind, and tornadoes will all be possible. Some significant wind gusts over 65 kts may occur.
- Drying out late Wednesday through Friday with more seasonable temperatures and humidity.
- Precipitation chances increase over the holiday weekend, but it will not be a wash out.
SHORT TERM /THROUGH TONIGHT/
Issued at 248 AM CDT Mon May 20 2024
Through sunrise two separate storm induced upper level disturbances will affect the area. The first will move into Wisconsin while the second rotates through eastern Iowa and northern Illinois. Forcing provided by both disturbances will keep convection going across the area. The very short term models are having difficulty handling the disturbances. However, trends from the HRRR/RAP suggest most of the areal coverage of the convection looks to be along and west of the Mississippi.
Storms along and west of the Mississippi will persist through mid- day Monday but gradually decrease in areal coverage as the second upper level disturbance moves into Wisconsin. The potential exists, albeit only a 20 percent chance, of much of the afternoon hours remaining dry as downward motion behind the departing upper level disturbance caps the atmosphere.
However, boundaries left over from the earlier storms combined with peak heating should allow isolated to scattered storms to develop mid to late afternoon. Any storm that develops may bring a hail/wind threat. The area favored looks to be south and east of a line from Dubuque, IA to Ottumwa, IA. The overall recovery of the atmosphere will dictate the severe potential for late afternoon and evening. The steep mid-level lapse rates that support storm development are actually over central and western Iowa. Thus activity over eastern Iowa and east of the Mississippi could remain isolated in nature.
Tonight will be interesting. Storms that fire in the Plains this afternoon will likely grow upscale into one or two lines that move east overnight. Steep mid-level lapse rates will initially help maintain the storms as they move east but cooling of the atmosphere with sunset should result in storms becoming weaker with time. Thus there are three possible scenarios.
Scenario 1 is the evening remains fairly quiet with little or no storms followed by an increase in storm coverage as the low level jet shifts east feeding moisture into the approaching storm system.
The HRRR is beginning to suggest this scenario and to a lesser extent the RAP.
Scenario 2 is the entire night remains mainly quiet due to decreasing mid-level lapse rates and the low level jet remains out in the Plains. The NAM suggests this scenario.
Scenario 3 is that isolated to low end scattered convection persists overnight while the stronger convection gets no further east than western Iowa. The NSSL WRF and to a lesser extent the FV3 suggest this scenario.
Scenario 1 is currently favored given the slightly better results the HRRR/RAP had with the Sunday night convection.
LONG TERM /TUESDAY THROUGH SUNDAY/
Issued at 248 AM CDT Mon May 20 2024
Tuesday...00z model solutions continue to show a very active severe weather day for the local area. Scattered showers and thunderstorms to be ongoing to start the period primarily in the northern half of the CWA in the WAA regime ahead of 996 surface low in northern KS aided by overnight LLJ. With some MLCAPE (1000 J/Kg), 30 kt deep layer shear, and PWs around 1.5" wouldn't be surprised to have an elevated hailer or two with penny/nickel hail during the morning hours along with heavy rain. This activity will lift north out of our area as the warm front lifts north near the IA/MN border in response of the surface low tracking into NW Iowa by 22z. This low location is further west and slower than previous model runs and makes sense with a negatively tilted trough. The question then becomes how quickly the atmosphere recovers in the warm sector.
Steeping mid level lapse rates in an elevated mixed layer (EML)
combined with a moist BL will allow for destabilization to occur ahead of cold front across the eastern 2/3rds of Iowa. RAP soundings in the afternoon show very high SBCAPE and MLCAPE values in excess of 2500 J/Kg, 55kt effective shear, and 25 kts of 0-1 km shear all supportive of supercells initially in the warm sector with large hail and tornadoes (possibly strong).
After CI occurs, large scale ascent and forcing along the front will allow for rapid upscale growth into a QLCS moving across Iowa. 0-3 km shear vectors over 40kts become close to line normal with the surface front which supports hazards transitioning into a damaging wind/QLCS tornado threat. Some significant wind gusts over 65 kts not out of the question as this system grows upscale. In addition, some heavy rainfall will be possible with this event, with PWs around 1.5 to 1.7 inches, which would be near the daily max for this time of year per SPC climatology. Thankfully, storm motions will be quite fast (over 50mph!) leading to not much residence time of heavy rainfall at any one point.
Regarding timing...latest CAMs and RAP/NAM model progs suggest this would develop late afternoon Tuesday (4pm) through late evening (11pm). An interesting note from the new 00z MPAS model run from NCAR shows several members initiating convection slightly further west over western IA at 21z before quickly moving east, which may suggest a slightly later time of storms arriving here. In any case, be weather aware Tuesday and stay up-to-date with the newest information as it unfolds.
Wednesday On...surface low to continue to fill and weaken over western Lake Superior. This will bring comfortable humidity levels, seasonable temperatures, and dry conditions across the CWA to end the work week. 850mb temps to remain below 11C through Friday. Highs in the 70s and lows in the 50s will be seen. Going into the holiday weekend, the 00z models diverge on their respective solutions and forecast confidence in precipitation chances decreases. Will maintain slight chance/chance PoPs through Sunday night for now, but there will be dry hours and this will be further refined in later forecasts.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
Issued at 521 AM CDT Mon May 20 2024
VFR conditions will prevail, but residual showers and storms will bring brief MVFR conditions. Cigs may drop between 2000-3500 ft, with decreases in visibility to 3-5 SM, especially in heavier showers. BRL should mostly be clear of these restrictions, but the remainder of the terminals will have these impacts through the morning. Thus, a TEMPO is out to cover this until 16z. From there, we should start to see things clear out and cigs increase, as clouds start to scatter out. Winds are quite variable at the moment, as multiple rounds of showers/storms resulted in several outflow boundaries, impacting wind direction throughout. Overall, easterly winds will shift southeasterly early, and then most areas will be southwesterly by 18z. Gusts upwards to 25 KTs will be possible, especially with any showers/storms.
DVN WATCHES/WARNINGS/ADVISORIES
IA...None.
IL...None.
MO...None.
Area Forecast Discussion National Weather Service Quad Cities IA IL 533 AM CDT Mon May 20 2024
KEY MESSAGES
- There is a marginal risk (level 1 of 5) for severe weather today. Hail up to quarters and 60 mph winds will be the primary threats with the strongest storms if they occur.
- There is an enhanced risk (level 3 of 5) for severe weather on Tuesday. Large hail, damaging wind, and tornadoes will all be possible. Some significant wind gusts over 65 kts may occur.
- Drying out late Wednesday through Friday with more seasonable temperatures and humidity.
- Precipitation chances increase over the holiday weekend, but it will not be a wash out.
SHORT TERM /THROUGH TONIGHT/
Issued at 248 AM CDT Mon May 20 2024
Through sunrise two separate storm induced upper level disturbances will affect the area. The first will move into Wisconsin while the second rotates through eastern Iowa and northern Illinois. Forcing provided by both disturbances will keep convection going across the area. The very short term models are having difficulty handling the disturbances. However, trends from the HRRR/RAP suggest most of the areal coverage of the convection looks to be along and west of the Mississippi.
Storms along and west of the Mississippi will persist through mid- day Monday but gradually decrease in areal coverage as the second upper level disturbance moves into Wisconsin. The potential exists, albeit only a 20 percent chance, of much of the afternoon hours remaining dry as downward motion behind the departing upper level disturbance caps the atmosphere.
However, boundaries left over from the earlier storms combined with peak heating should allow isolated to scattered storms to develop mid to late afternoon. Any storm that develops may bring a hail/wind threat. The area favored looks to be south and east of a line from Dubuque, IA to Ottumwa, IA. The overall recovery of the atmosphere will dictate the severe potential for late afternoon and evening. The steep mid-level lapse rates that support storm development are actually over central and western Iowa. Thus activity over eastern Iowa and east of the Mississippi could remain isolated in nature.
Tonight will be interesting. Storms that fire in the Plains this afternoon will likely grow upscale into one or two lines that move east overnight. Steep mid-level lapse rates will initially help maintain the storms as they move east but cooling of the atmosphere with sunset should result in storms becoming weaker with time. Thus there are three possible scenarios.
Scenario 1 is the evening remains fairly quiet with little or no storms followed by an increase in storm coverage as the low level jet shifts east feeding moisture into the approaching storm system.
The HRRR is beginning to suggest this scenario and to a lesser extent the RAP.
Scenario 2 is the entire night remains mainly quiet due to decreasing mid-level lapse rates and the low level jet remains out in the Plains. The NAM suggests this scenario.
Scenario 3 is that isolated to low end scattered convection persists overnight while the stronger convection gets no further east than western Iowa. The NSSL WRF and to a lesser extent the FV3 suggest this scenario.
Scenario 1 is currently favored given the slightly better results the HRRR/RAP had with the Sunday night convection.
LONG TERM /TUESDAY THROUGH SUNDAY/
Issued at 248 AM CDT Mon May 20 2024
Tuesday...00z model solutions continue to show a very active severe weather day for the local area. Scattered showers and thunderstorms to be ongoing to start the period primarily in the northern half of the CWA in the WAA regime ahead of 996 surface low in northern KS aided by overnight LLJ. With some MLCAPE (1000 J/Kg), 30 kt deep layer shear, and PWs around 1.5" wouldn't be surprised to have an elevated hailer or two with penny/nickel hail during the morning hours along with heavy rain. This activity will lift north out of our area as the warm front lifts north near the IA/MN border in response of the surface low tracking into NW Iowa by 22z. This low location is further west and slower than previous model runs and makes sense with a negatively tilted trough. The question then becomes how quickly the atmosphere recovers in the warm sector.
Steeping mid level lapse rates in an elevated mixed layer (EML)
combined with a moist BL will allow for destabilization to occur ahead of cold front across the eastern 2/3rds of Iowa. RAP soundings in the afternoon show very high SBCAPE and MLCAPE values in excess of 2500 J/Kg, 55kt effective shear, and 25 kts of 0-1 km shear all supportive of supercells initially in the warm sector with large hail and tornadoes (possibly strong).
After CI occurs, large scale ascent and forcing along the front will allow for rapid upscale growth into a QLCS moving across Iowa. 0-3 km shear vectors over 40kts become close to line normal with the surface front which supports hazards transitioning into a damaging wind/QLCS tornado threat. Some significant wind gusts over 65 kts not out of the question as this system grows upscale. In addition, some heavy rainfall will be possible with this event, with PWs around 1.5 to 1.7 inches, which would be near the daily max for this time of year per SPC climatology. Thankfully, storm motions will be quite fast (over 50mph!) leading to not much residence time of heavy rainfall at any one point.
Regarding timing...latest CAMs and RAP/NAM model progs suggest this would develop late afternoon Tuesday (4pm) through late evening (11pm). An interesting note from the new 00z MPAS model run from NCAR shows several members initiating convection slightly further west over western IA at 21z before quickly moving east, which may suggest a slightly later time of storms arriving here. In any case, be weather aware Tuesday and stay up-to-date with the newest information as it unfolds.
Wednesday On...surface low to continue to fill and weaken over western Lake Superior. This will bring comfortable humidity levels, seasonable temperatures, and dry conditions across the CWA to end the work week. 850mb temps to remain below 11C through Friday. Highs in the 70s and lows in the 50s will be seen. Going into the holiday weekend, the 00z models diverge on their respective solutions and forecast confidence in precipitation chances decreases. Will maintain slight chance/chance PoPs through Sunday night for now, but there will be dry hours and this will be further refined in later forecasts.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
Issued at 521 AM CDT Mon May 20 2024
VFR conditions will prevail, but residual showers and storms will bring brief MVFR conditions. Cigs may drop between 2000-3500 ft, with decreases in visibility to 3-5 SM, especially in heavier showers. BRL should mostly be clear of these restrictions, but the remainder of the terminals will have these impacts through the morning. Thus, a TEMPO is out to cover this until 16z. From there, we should start to see things clear out and cigs increase, as clouds start to scatter out. Winds are quite variable at the moment, as multiple rounds of showers/storms resulted in several outflow boundaries, impacting wind direction throughout. Overall, easterly winds will shift southeasterly early, and then most areas will be southwesterly by 18z. Gusts upwards to 25 KTs will be possible, especially with any showers/storms.
DVN WATCHES/WARNINGS/ADVISORIES
IA...None.
IL...None.
MO...None.
Quad Cities, IA,
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