Marine Weather and Tide Forecast for Yankton, SD
July 3, 2024 5:29 AM CDT (10:29 UTC) Change Location
 | Sunrise 5:49 AM Sunset 9:12 PM Moonrise 2:23 AM Moonset 6:44 PM |
Area Discussion for - Sioux Falls, SD
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FXUS63 KFSD 030839 AFDFSD
Area Forecast Discussion National Weather Service Sioux Falls SD 339 AM CDT Wed Jul 3 2024
KEY MESSAGES
- Showers and thunderstorms are expected to develop this afternoon and move into locations west of the James River Valley. Some of these storms could be strong to severe with large hail to the size of quarters and damaging winds to 60 mph. Heavy rainfall is also possible west of the James.
- A second round of showers and thunderstorms is expected on Thursday/Independence Day. Heavy rainfall is possible, mainly east of I-29 but looks to be more localized then widespread. Severe weather chances are uncertain but funnels to perhaps a brief tornado is possible.
- Below normal temperatures continue tomorrow and into early next week with high temperatures on the order of near seasonable to 5 to 10 degrees below average.
DISCUSSION
Issued at 337 AM CDT Wed Jul 3 2024
Quiet conditions begin the day today as surface ridging continues to slide through the area. Given clear skies and light winds, patchy fog may be possible, most likely along river valleys. The surface ridge will slide past the forecast area through the morning hours.
With the center of the surface high sliding across the Nebraska, Iowa, Missouri, and Kansas state borders, southerly return flow will set up, setting the stage for the next chance for showers and storms. The return flow will not be impressive, especially for this time of year as dew points will only moisten to the upper 50s to low 60s across north central Nebraska and south central South Dakota.
This will result in lesser CAPE values only up to around 1,000 J/kg.
Some uncertainty regarding the magnitude of instability is in question for the afternoon hours as soundings show diurnal mixing reducing buoyancy. In terms of shear, an upper level jet streak will have the overall entrance region parked over the forecast area, providing strong speed shear via mainly straight hodographs with deep layer shear values on the order of 40-50 knots. Convection looks to fire on the warm front parked along the South Dakota/Nebraska border (west of the CWA) as a mid level wave hits the front this afternoon. With an overall more stable airmass over the forecast area, think convection will be on a downward trend as it moves into the Missouri River and James River Valley's. However, with some instability and sufficient shear to work with, think large hail to the size of quarters and damaging winds to 60 mph are possible.
The storms will push into the area during the late afternoon and evening hours before a second round of showers and storms will come in on its heels for the evening and overnight hours. This round will be forced by an upper level wave pushing into the Northern Plains.
This second round of storms will encounter the environment that the first round of storms developed in. Given the modified environment, do not expect this second round to be severe but will contribute to additional rainfall. Rainfall totals for Wednesday are expected to be between 0.25" to 0.75" with isolated higher amounts up to around an inch, with the highest amounts falling along and west of the James River. Aside from rain and storm chances, high temperatures will be seasonal in the 80s with low temperatures falling to the 60s.
The previously mentioned upper level wave will evolve into a closed low on Thursday/Independence Day. Abundant cloud cover and cooler mid level temperatures will result in cooler high temperatures with highs only warming to the 70s. The cooler mid level temperatures will also steepen mid level lapse rates a bit to generate some buoyancy. However, the amount of CAPE remains somewhat uncertain as it will depend on how the low levels can destabilize. If clouds are able to break up enough to allow adequate surface heating, then could see CAPE values up to around 1,000 J/kg during the afternoon hours. If not, then instability will be on the lower side, below 1,000 J/kg. Shear is also questionable as small pivots in where the upper low tracks could result in increased or decreased shear. If the low wobbles further north, then better jet energy will be brought northward and contribute to sufficient vertical shear. If the low wobbles further south, then weaker shear would be expected.
With at least some overlap of shear and instability, scattered showers and thunderstorms are expected throughout the day. Ensembles point to locations north of I-90, mainly in southwest Minnesota, having the highest chances for additional heavy rainfall. The GFS, Euro, and Canadian ensembles all show a near 100% chance for exceeding a half an inch of rain and a 30-50% chance for exceeding an inch of rain. Hi-res guidance does depict scattered showers and thunderstorms throughout the day. This could result in more isolated heavy rainfall depending on where storms track rather then widespread rainfall. The questionable environment also keeps severe weather chances questionable. If better shear and instability can be realized, then severe weather may come to fruition. However, a cold front will be pushing through the area which could severe as a focal point for funnels or brief tornado. 03z RAP shoes sufficient surface vorticity along the cold front as it moves through the area. As of now, locations east of I-29 have the highest potential to see funnel clouds and a brief tornado but could see funnels potentially across a more widespread part of the forecast area given the upper level low overhead. Any chance for rain will come to an end during the evening and overnight hours as the low levels stabilize. Low temperatures will fall to the upper 50s and 60s overnight.
The upper level low will begin to push eastwards of the area on Friday, resulting in cooler northwest flow for the day. High temperatures will remain on the cool side only warming to the 70s.
Some wrap around moisture will contribute to another chance for scattered showers throughout the day. Low temperatures will fall to the 50s overnight.
Medium range guidance continues to be in agreement in an amplified upper level pattern developing for the weekend. An upper level ridge will be be parked across the western CONUS with troughing across the eastern half of the US. Latest guidance continues to pull the ridge a little bit further west, placing more troughing across the Northern Plains. This looks to keep cooler conditions going through the weekend and into early next week. Ensembles support this as they show near seasonable temperatures to temperatures 10 degrees below average during this period of time. With troughing over the area for a large part of this time frame, chances for rain will develop with any shortwave that passes through the upper level flow. Tough to say when any period may have higher chances for rain as of now. Although Saturday may have the best chance as of now as medium range guidance is in decent agreement in a shortwave passing through the upper level flow. Ensembles support this as they show a broad 40-80% chance for exceeding a tenth of an inch of rain.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
Issued at 1038 PM CDT Tue Jul 2 2024
Patchy fog remains the biggest aviation concern as we reach our cross over temperatures, with models continuing to indicate best chances (20-30%) for patchy fog should occur along the southern Big Sioux and other low-lying areas south of I-90. Would not be surprised to see chances for fog expand, but for now have kept chances for fog mention only for the KSUX terminal. Dry conditions continue into the morning hours, before chances for scattered showers and thunderstorms return throughout the afternoon hours well west of I-29.
FSD WATCHES/WARNINGS/ADVISORIES
SD...None.
MN...None.
IA...None.
NE...None.
Area Forecast Discussion National Weather Service Sioux Falls SD 339 AM CDT Wed Jul 3 2024
KEY MESSAGES
- Showers and thunderstorms are expected to develop this afternoon and move into locations west of the James River Valley. Some of these storms could be strong to severe with large hail to the size of quarters and damaging winds to 60 mph. Heavy rainfall is also possible west of the James.
- A second round of showers and thunderstorms is expected on Thursday/Independence Day. Heavy rainfall is possible, mainly east of I-29 but looks to be more localized then widespread. Severe weather chances are uncertain but funnels to perhaps a brief tornado is possible.
- Below normal temperatures continue tomorrow and into early next week with high temperatures on the order of near seasonable to 5 to 10 degrees below average.
DISCUSSION
Issued at 337 AM CDT Wed Jul 3 2024
Quiet conditions begin the day today as surface ridging continues to slide through the area. Given clear skies and light winds, patchy fog may be possible, most likely along river valleys. The surface ridge will slide past the forecast area through the morning hours.
With the center of the surface high sliding across the Nebraska, Iowa, Missouri, and Kansas state borders, southerly return flow will set up, setting the stage for the next chance for showers and storms. The return flow will not be impressive, especially for this time of year as dew points will only moisten to the upper 50s to low 60s across north central Nebraska and south central South Dakota.
This will result in lesser CAPE values only up to around 1,000 J/kg.
Some uncertainty regarding the magnitude of instability is in question for the afternoon hours as soundings show diurnal mixing reducing buoyancy. In terms of shear, an upper level jet streak will have the overall entrance region parked over the forecast area, providing strong speed shear via mainly straight hodographs with deep layer shear values on the order of 40-50 knots. Convection looks to fire on the warm front parked along the South Dakota/Nebraska border (west of the CWA) as a mid level wave hits the front this afternoon. With an overall more stable airmass over the forecast area, think convection will be on a downward trend as it moves into the Missouri River and James River Valley's. However, with some instability and sufficient shear to work with, think large hail to the size of quarters and damaging winds to 60 mph are possible.
The storms will push into the area during the late afternoon and evening hours before a second round of showers and storms will come in on its heels for the evening and overnight hours. This round will be forced by an upper level wave pushing into the Northern Plains.
This second round of storms will encounter the environment that the first round of storms developed in. Given the modified environment, do not expect this second round to be severe but will contribute to additional rainfall. Rainfall totals for Wednesday are expected to be between 0.25" to 0.75" with isolated higher amounts up to around an inch, with the highest amounts falling along and west of the James River. Aside from rain and storm chances, high temperatures will be seasonal in the 80s with low temperatures falling to the 60s.
The previously mentioned upper level wave will evolve into a closed low on Thursday/Independence Day. Abundant cloud cover and cooler mid level temperatures will result in cooler high temperatures with highs only warming to the 70s. The cooler mid level temperatures will also steepen mid level lapse rates a bit to generate some buoyancy. However, the amount of CAPE remains somewhat uncertain as it will depend on how the low levels can destabilize. If clouds are able to break up enough to allow adequate surface heating, then could see CAPE values up to around 1,000 J/kg during the afternoon hours. If not, then instability will be on the lower side, below 1,000 J/kg. Shear is also questionable as small pivots in where the upper low tracks could result in increased or decreased shear. If the low wobbles further north, then better jet energy will be brought northward and contribute to sufficient vertical shear. If the low wobbles further south, then weaker shear would be expected.
With at least some overlap of shear and instability, scattered showers and thunderstorms are expected throughout the day. Ensembles point to locations north of I-90, mainly in southwest Minnesota, having the highest chances for additional heavy rainfall. The GFS, Euro, and Canadian ensembles all show a near 100% chance for exceeding a half an inch of rain and a 30-50% chance for exceeding an inch of rain. Hi-res guidance does depict scattered showers and thunderstorms throughout the day. This could result in more isolated heavy rainfall depending on where storms track rather then widespread rainfall. The questionable environment also keeps severe weather chances questionable. If better shear and instability can be realized, then severe weather may come to fruition. However, a cold front will be pushing through the area which could severe as a focal point for funnels or brief tornado. 03z RAP shoes sufficient surface vorticity along the cold front as it moves through the area. As of now, locations east of I-29 have the highest potential to see funnel clouds and a brief tornado but could see funnels potentially across a more widespread part of the forecast area given the upper level low overhead. Any chance for rain will come to an end during the evening and overnight hours as the low levels stabilize. Low temperatures will fall to the upper 50s and 60s overnight.
The upper level low will begin to push eastwards of the area on Friday, resulting in cooler northwest flow for the day. High temperatures will remain on the cool side only warming to the 70s.
Some wrap around moisture will contribute to another chance for scattered showers throughout the day. Low temperatures will fall to the 50s overnight.
Medium range guidance continues to be in agreement in an amplified upper level pattern developing for the weekend. An upper level ridge will be be parked across the western CONUS with troughing across the eastern half of the US. Latest guidance continues to pull the ridge a little bit further west, placing more troughing across the Northern Plains. This looks to keep cooler conditions going through the weekend and into early next week. Ensembles support this as they show near seasonable temperatures to temperatures 10 degrees below average during this period of time. With troughing over the area for a large part of this time frame, chances for rain will develop with any shortwave that passes through the upper level flow. Tough to say when any period may have higher chances for rain as of now. Although Saturday may have the best chance as of now as medium range guidance is in decent agreement in a shortwave passing through the upper level flow. Ensembles support this as they show a broad 40-80% chance for exceeding a tenth of an inch of rain.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
Issued at 1038 PM CDT Tue Jul 2 2024
Patchy fog remains the biggest aviation concern as we reach our cross over temperatures, with models continuing to indicate best chances (20-30%) for patchy fog should occur along the southern Big Sioux and other low-lying areas south of I-90. Would not be surprised to see chances for fog expand, but for now have kept chances for fog mention only for the KSUX terminal. Dry conditions continue into the morning hours, before chances for scattered showers and thunderstorms return throughout the afternoon hours well west of I-29.
FSD WATCHES/WARNINGS/ADVISORIES
SD...None.
MN...None.
IA...None.
NE...None.
Link to 1 hour of 5 minute data for KYKN
Terminal Aerodrome Forecast (TAF) for KYKN
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Terminal Aerodrome Forecast (TAF) for KYKN
Wind History graph: YKN
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Sioux falls, SD,
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