Marine Weather and Tides
12/16/2019 NOAA is having trouble with requests that include wind gusts. I am posting graphs without wind gusts until it gets fixed.
10/9/2019 Updated the Marine Zones.
9/4/2019 Fixed the weather maps due to NOAA moving them.
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.
|Sunrise 6:18AM||Sunset 8:46PM||Tuesday August 4, 2020 9:24 AM CDT (14:24 UTC)||Moonrise 8:50PM||Moonset 6:10AM||Illumination 100%|
7 Day Forecast for Marine Location Near Yankton, SDHourly EDIT Help
Area Discussion for - Sioux Falls, SD  (on/off)  Help NOTE: mouseover dotted underlined text for definition
FXUS63 KFSD 041133 AFDFSD
AREA FORECAST DISCUSSION National Weather Service Sioux Falls SD 633 AM CDT Tue Aug 4 2020
SHORT TERM. (Today and Tonight) Issued at 400 AM CDT Tue Aug 4 2020
Surface ridge over far eastern CWA early this morning will slide east today, allowing for modest southerly return flow. This will begin to draw some near 60F dew points back into western areas, while our eastern counties enjoy one more day of dew points in the lower 50s.
Subtle 850mb warm advection works into our far western counties by 21Z-00Z as weak mid-level wave slides southeast into central SD. This could provide enough lift for scattered development as early as mid afternoon, though models differ on timing/location of initiation, with several CAMs leaning faster/farther east than coarser models like GFS/NAM.
MUCAPE peaks just over 1000J/kg in our far western counties, with weak mid-level lapse rates leading to tall/skinny CAPE profiles. However, stronger deep layer shear works into that area thanks to directional shear below 7kft, and increasing wind speeds above that level. The stronger shear could overcome the modest instability to support isolated organized cells capable of marginally severe hail or wind, though greater severe potential should be west/southwest of our area where instability is greater.
Stronger trailing wave drops southeast through North Dakota into eastern South Dakota later tonight, which along with eastward push of warm advection should support scattered convection working toward the I-29 corridor by daybreak Wednesday. Coverage/intensity should gradually wane overnight as the activity moves into less unstable air mass east of the James River.
LONG TERM. (Wednesday through Monday) Issued at 400 AM CDT Tue Aug 4 2020
Wednesday/Wednesday night remain unsettled as broad upper wave continues to slide across Minnesota. Several models indicate this wave inducing a surface wave in northeast South Dakota by mid-late afternoon, with a warm front stretching southeast into southwest Minnesota, and subtle dry line south into our South Dakota Counties. With the greater influence of the upper wave across Minnesota, will keep highest pops near the weak warm front in southwest Minnesota by late afternoon. However, could see isolated-scattered development farther south in the warm sector ahead of the dry line where MLCAPE values push toward 1500-2000J/kg during peak heating. Similar to today, mid-level lapse rates are rather weak with tall/skinny CAPE profiles, so severe potential will be more dependent on shear to sustain organized updrafts. While we still have some directional shear in the lower levels, mid-upper level speeds show more variance among different models, so severe potential is more uncertain. Still cannot rule out isolated stronger storms in the late afternoon/early evening if shear is strong enough to support.
Chance of storms will linger across southeast forecast area through later Wednesday night as the wave and associated boundaries continue to push east.
Latter part of the week into next weekend will become dominated by warmer and more humid air, with subtle waves sliding across the region as weak upper ridging becomes quasi-zonal as stronger trough moves across western/central Canada. Precipitation chances difficult to pinpoint with models showing little agreement on timing of the weak waves. However, with warm/humid air mass so prevalent, think tendency would lean toward isolated nighttime/early morning convection chances. Currently forecast heat indices holding just shy of heat advisory criteria Friday-Sunday, but will have to watch this period in case warmer and/or more humid air works into the region than current blends indicate.
AVIATION. (For the 12Z TAFS through 12Z Wednesday morning) Issued at 633 AM CDT Tue Aug 4 2020
VFR conditions are expected to prevail through the period, with light/variable winds early becoming south-southeasterly through the morning, possibly gusting near 20kts in areas near/west of the James River this afternoon.
While isolated-scattered convection may spread from the Missouri River Valley toward I-29 from mid-afternoon through the end of the TAF period, confidence in timing/coverage in areas along/east of the James River is very low. Thus have not included a mention of thunder in any of our TAFs at this time. Slightly higher confidence that storms will impact areas west of the James River toward south central South Dakota during the late afternoon/early evening.
FSD WATCHES/WARNINGS/ADVISORIES. SD . NONE. MN . NONE. IA . NONE. NE . NONE.
SHORT TERM . JH LONG TERM . JH AVIATION . JH
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|Yankton, Chan Gurney Municipal Airport, SD||2 mi||29 min||ESE 4||10.00 mi||Fair||61°F||55°F||84%||1022.1 hPa|
Link to 5 minute data for KYKN
Wind History from YKN (wind in knots)
|1 day ago||NW||NW||NW||N|
|2 days ago||NW||NW||N||N|
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GEOS Local Image of EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Other links: Northern Pacific Contential US Full GOES-East
Wind Forecast for Sioux Falls, SD (10,2,3,4)(on/off)  Help
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