Marine Weather and Tide Forecast for Vermillion, SD
May 18, 2024 4:22 AM CDT (09:22 UTC) Change Location
 | Sunrise 5:58 AM Sunset 8:45 PM Moonrise 3:06 PM Moonset 2:46 AM |
Area Discussion for - Sioux Falls, SD
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FXUS63 KFSD 180344 AFDFSD
Area Forecast Discussion National Weather Service Sioux Falls SD 1044 PM CDT Fri May 17 2024
KEY MESSAGES
- Isolated thunderstorms may develop late Friday afternoon and evening over SW Minnesota and adjacent areas of Iowa and South Dakota. Non-severe storms could bring a few reports of hail or gusty winds.
- Thunderstorm chances return late Sunday into Monday, with a continued uncertain potential for severe weather.
- The highest focus for convection arrives Monday night into Tuesday bringing a risk for severe storms to the Tri-State area along with widespread potential for 1-2+ inches of rainfall. This rainfall could bring some rivers back into flooding levels.
- Cooler temperatures but continued unsettled weather remains through the rest of next week.
DISCUSSION
Issued at 236 PM CDT Fri May 17 2024
THIS AFTERNOON: A very warm day across the Tri-State area as temperatures have risen into the middle and upper 80s in most areas. Some areas will likely see a late day surge to 90, as mixing intensifies. There remains a narrow tongue of surface dew points in the lower to middle 50s in the CWA With the increased surface convergence this afternoon, it's not out of the realm of possibility to see a few high based thunderstorms form along a line from near Yankton to Sioux Falls to Marshall/Windom later today. MLCAPE may approach 500 to 900 J/KG along this line, and while the severe weather risk is low, given sharpening mid-lvl lapse rates some small hail or localized wind gusts could be possible.
TONIGHT: Lingering isolated thunderstorms may persist through mid- evening before dissipating. Additional convection is likely over the western Dakotas later tonight along an area of low pressure and surface front. This front will push eastward overnight with an area of elevated moisture likely developing into ACCAS overnight as it moves eastward. A few high based showers/virga are possible across most of the Tri-state area through 9am Saturday. Behind this front, CAMs all suggest potential for 35 to 45 mph winds moving into central South Dakota by 3-4am, and the James River valley by 7am.
Winds are expected to weaken as they travel east and the brevity of higher winds may be too short to issue an advisory for ATTM.
SATURDAY: Breezy west to northwest winds will prevail through Saturday, though wind gusts will fall into the 20 to 25 mph range by the afternoon. Fairly dry air is expected to both advect southeast and then mix down in the afternoon, and have also favored temperatures slightly above the NBM in the afternoon.
SUNDAY: High pressure slides through the Tri-State area Saturday night into Sunday, however broad warm advection and a subtle shortwave is likely to initiate convection over the Nebraska Panhandle and western Kansas overnight. Some sort of MCS may develop and track into eastern Nebraska and northwest Iowa early Sunday. The GFS/NAM/GEM all remain focused over the southern counties for heavier rain, while the ECMWF is shifted a few counties further north. If a larger scale MCS does develop, it could interrupt moisture and potential for any further north isolated development across the Dakotas. At this point morning activity will likely not be severe. We will however had to watch for some increased potential later in the evening and overnight though this remains highly uncertain. If further south tracks of morning activity verify, then more focus towards afternoon and evening activity develop along a boundary over the western Dakotas late in the afternoon. This activity would then track eastward overnight, it would likely continue eastward though a MUCAPE pool of 1500-2000 J/KG until weakening near the James River. Could see potential eastward expansion of SPC outlooks towards the James River Valley and further into the Dakotas.
MONDAY-TUESDAY: Broad southwesterly flow leads to a very complex and then potentially wet forecast for a large portion of next week.
By Monday morning a surface front will try to settle into Northwest Iowa. A cooler day is likely Monday with lingering clouds, and this will keep temperatures into the upper 60s to lower 70s. However, the pattern setting up would be favorable for sharply increasing PoPs by Monday evening into Tuesday. A deeper influx of moisture is expected to arrive late Monday, pushing PW values towards 1.5".
Wherever the surface boundary falls, only modest inhibition may exist by the evening, increasing the potential for a few stronger surface based storms. MLCAPE between 1500-2000 J/KG along with a modest increase in effective shear towards 35 knots, could produce an increased severe weather risk in the evening. Greater convection risks develop after dark however as the LLJ and low-lvl frontal circulation increases, mid-lvl dPVA develops, and broad upper diffluence from an approaching upper jet moves into the area. This will produce the potential for a fairly large area of heavy rainfall potential. GEFS/ECE probabilities for >1" rain break the 70% range, with probabilities for >2" of rain already at 20%. Some initial severe weather risk may continue into the early overnight hours, mainly due to an elevated hail risk. Both the CSU Machine- learning probabilities along with the CIPS analogs both support the potential for further north expansions of the severe weather outlooks from SPC.
WEDNESDAY-FRIDAY: We're going to remain quite active through most of next week as a large trough remains centered over southern Canada.
This trough is going to keep a risk for showers and thunderstorms nearly every other day into next weekend, along with a drop in temperatures towards or even slightly below seasonal normals.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
Issued at 1043 PM CDT Fri May 17 2024
VFR conditions are expected for the TAF period. The low level jet (LLJ) has strengthened this evening, leading to low level wind shear (LLWS) across the area which will persist through the overnight hours. The LLJ will also keep gusty southerly winds through most of the night with gusts up to 20-30 knots. A cold front currently over central South Dakota will push eastwards through the area during the overnight hours. Sprinkles to very light rain showers are possible but confidence remains too low to put in a TAF. A small period of stronger gusts up 35-40 knots is expected west of I-29. Winds will swing to out of the northwest behind the front and remain gusty through the rest of tomorrow with gusts up to 20-30 knots expected.
Winds will slowly wane through the afternoon and evening hours.
FSD WATCHES/WARNINGS/ADVISORIES
SD...None.
MN...None.
IA...None.
NE...None.
Area Forecast Discussion National Weather Service Sioux Falls SD 1044 PM CDT Fri May 17 2024
KEY MESSAGES
- Isolated thunderstorms may develop late Friday afternoon and evening over SW Minnesota and adjacent areas of Iowa and South Dakota. Non-severe storms could bring a few reports of hail or gusty winds.
- Thunderstorm chances return late Sunday into Monday, with a continued uncertain potential for severe weather.
- The highest focus for convection arrives Monday night into Tuesday bringing a risk for severe storms to the Tri-State area along with widespread potential for 1-2+ inches of rainfall. This rainfall could bring some rivers back into flooding levels.
- Cooler temperatures but continued unsettled weather remains through the rest of next week.
DISCUSSION
Issued at 236 PM CDT Fri May 17 2024
THIS AFTERNOON: A very warm day across the Tri-State area as temperatures have risen into the middle and upper 80s in most areas. Some areas will likely see a late day surge to 90, as mixing intensifies. There remains a narrow tongue of surface dew points in the lower to middle 50s in the CWA With the increased surface convergence this afternoon, it's not out of the realm of possibility to see a few high based thunderstorms form along a line from near Yankton to Sioux Falls to Marshall/Windom later today. MLCAPE may approach 500 to 900 J/KG along this line, and while the severe weather risk is low, given sharpening mid-lvl lapse rates some small hail or localized wind gusts could be possible.
TONIGHT: Lingering isolated thunderstorms may persist through mid- evening before dissipating. Additional convection is likely over the western Dakotas later tonight along an area of low pressure and surface front. This front will push eastward overnight with an area of elevated moisture likely developing into ACCAS overnight as it moves eastward. A few high based showers/virga are possible across most of the Tri-state area through 9am Saturday. Behind this front, CAMs all suggest potential for 35 to 45 mph winds moving into central South Dakota by 3-4am, and the James River valley by 7am.
Winds are expected to weaken as they travel east and the brevity of higher winds may be too short to issue an advisory for ATTM.
SATURDAY: Breezy west to northwest winds will prevail through Saturday, though wind gusts will fall into the 20 to 25 mph range by the afternoon. Fairly dry air is expected to both advect southeast and then mix down in the afternoon, and have also favored temperatures slightly above the NBM in the afternoon.
SUNDAY: High pressure slides through the Tri-State area Saturday night into Sunday, however broad warm advection and a subtle shortwave is likely to initiate convection over the Nebraska Panhandle and western Kansas overnight. Some sort of MCS may develop and track into eastern Nebraska and northwest Iowa early Sunday. The GFS/NAM/GEM all remain focused over the southern counties for heavier rain, while the ECMWF is shifted a few counties further north. If a larger scale MCS does develop, it could interrupt moisture and potential for any further north isolated development across the Dakotas. At this point morning activity will likely not be severe. We will however had to watch for some increased potential later in the evening and overnight though this remains highly uncertain. If further south tracks of morning activity verify, then more focus towards afternoon and evening activity develop along a boundary over the western Dakotas late in the afternoon. This activity would then track eastward overnight, it would likely continue eastward though a MUCAPE pool of 1500-2000 J/KG until weakening near the James River. Could see potential eastward expansion of SPC outlooks towards the James River Valley and further into the Dakotas.
MONDAY-TUESDAY: Broad southwesterly flow leads to a very complex and then potentially wet forecast for a large portion of next week.
By Monday morning a surface front will try to settle into Northwest Iowa. A cooler day is likely Monday with lingering clouds, and this will keep temperatures into the upper 60s to lower 70s. However, the pattern setting up would be favorable for sharply increasing PoPs by Monday evening into Tuesday. A deeper influx of moisture is expected to arrive late Monday, pushing PW values towards 1.5".
Wherever the surface boundary falls, only modest inhibition may exist by the evening, increasing the potential for a few stronger surface based storms. MLCAPE between 1500-2000 J/KG along with a modest increase in effective shear towards 35 knots, could produce an increased severe weather risk in the evening. Greater convection risks develop after dark however as the LLJ and low-lvl frontal circulation increases, mid-lvl dPVA develops, and broad upper diffluence from an approaching upper jet moves into the area. This will produce the potential for a fairly large area of heavy rainfall potential. GEFS/ECE probabilities for >1" rain break the 70% range, with probabilities for >2" of rain already at 20%. Some initial severe weather risk may continue into the early overnight hours, mainly due to an elevated hail risk. Both the CSU Machine- learning probabilities along with the CIPS analogs both support the potential for further north expansions of the severe weather outlooks from SPC.
WEDNESDAY-FRIDAY: We're going to remain quite active through most of next week as a large trough remains centered over southern Canada.
This trough is going to keep a risk for showers and thunderstorms nearly every other day into next weekend, along with a drop in temperatures towards or even slightly below seasonal normals.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
Issued at 1043 PM CDT Fri May 17 2024
VFR conditions are expected for the TAF period. The low level jet (LLJ) has strengthened this evening, leading to low level wind shear (LLWS) across the area which will persist through the overnight hours. The LLJ will also keep gusty southerly winds through most of the night with gusts up to 20-30 knots. A cold front currently over central South Dakota will push eastwards through the area during the overnight hours. Sprinkles to very light rain showers are possible but confidence remains too low to put in a TAF. A small period of stronger gusts up 35-40 knots is expected west of I-29. Winds will swing to out of the northwest behind the front and remain gusty through the rest of tomorrow with gusts up to 20-30 knots expected.
Winds will slowly wane through the afternoon and evening hours.
FSD WATCHES/WARNINGS/ADVISORIES
SD...None.
MN...None.
IA...None.
NE...None.
| Airport | Dist | Age | Wind kt | Vis | Sky | Weather | Temp | DewPt | RH | inHg |
| KYKN CHAN GURNEY MUNI,SD | 21 sm | 26 min | SSW 15G20 | 10 sm | Clear | 72°F | 54°F | 53% | 29.52 |
Sioux falls, SD,
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