Marine Weather and Tides
3/30/2021 -- ANZ330 has been split into ANZ331 and ANZ332. Click EDIT in Marine Forecast and select your new zone.
1/26/2021 -- The West Coast Satellite images havd been updated. They now use GEOS-17.
1/1/2021 -- The 7 day forecast are now working well. Thank you NOAA for your support.
|Sunrise 6:52AM||Sunset 7:01PM||Thursday September 23, 2021 1:49 PM CDT (18:49 UTC)||Moonrise 7:26PM||Moonset 8:27AM||Illumination 94%|
7 Day Forecast for Marine Location Near Sparta, WIHourly EDIT Help
Area Discussion for - La Crosse, WI  (on/off)  Help NOTE: mouseover dotted underlined text for definition
FXUS63 KARX 231730 AFDARX
Area Forecast Discussion National Weather Service La Crosse WI 1230 PM CDT Thu Sep 23 2021
SHORT TERM. (Today and tonight) Issued at 259 AM CDT Thu Sep 23 2021
Frost advisory for the bogs and northern counties as temperatures forecasted to reach the low and mid 30s. Patchy fog forecasted for the tributaries with a light wind layer (<5kts) up to 1000 ft. Not expected to be a widespread event with a dry boundary layer air mass maintaining fog-inhibitive dewpoint depressions. This dry air is a result of an upstream upper-level ridge which will provide similar weather today as the last couple of days. Likely more than just cumulus clouds in our eastern counties from the downstream low pressure system. Warm air advection tonight has 850 mb temps increasing by 5 deg C, ahead of our next disturbance on Friday. This keeps tonight's overnight lows in the high 30s to high 40s and removes likelihood of having another frost advisory.
LONG TERM. (Friday through Wednesday) Issued at 259 AM CDT Thu Sep 23 2021
Clouds build Friday morning ahead of an upper-level trough digging southeast across the Northern Plains into the Midwest. These clouds will likely limit surface instability from building for most of our area ahead of the favorable mid-level vorticity advection later in the afternoon. Highest chances of precipitation are for the afternoon into the early evening. Sounding data alludes to convective activity remaining elevated with tall and skinny CAPE for most of our area. Our southern-most counties will have a longer available window to build surface instability and have slightly more prominent thicker CAPE profiles. They may be able to reach convective temperatures and have included chance of thunder for the evening in those parts and only isolated farther northwest earlier in the day. Still do not expect anything to be severe with minimal instability and shear coming late to the scene, not building until the evening hours. That said, will need to watch our southern counties. The latest version of the HRRR does enhance development as it moves into MKX's area and would tap this better shear. All of the EPS members forecast measurable precipitation while only half of the GEFS members forecast similarly.
The surface frontal boundary eventually passes Friday night, reintroducing single digit 850 mb temps for Saturday and a temporary return to mid 60F surface temperatures. The NAM12 appears to be an outlier with stronger cyclonic flow southwestward Saturday into the area with even cooler temperatures. The upper-level trough passes Saturday night, ushering in upper-level ridging and northwest flow to our forecast area. Warm air advection increases 850 mb temps by 10C Sunday, placing them in the 90th percentile according to NAEFS and ENS for this time of year. In turn, surface temperatures become unseasonably warm for the beginning of next week. GEFS spread is high with a mean max temperature of low 80s deg F for Mon, Tues, and Weds. EPS is more reserved at high 70s, except for Tuesday at 83. The ECMWF even brings in the 20 deg C isotherm at 850 mb for a showing on Tuesday. Dry adiabatically mixing out a 20C 850 mb temperature would result in a max surface temperature in the mid 80s.
AVIATION. (For the 18Z TAFS through 18Z Friday afternoon) Issued at 1230 PM CDT Thu Sep 23 2021
A ridge of high pressure will continue to provide mainly clear skies and light surface winds into tonight. Unlike this morning, the winds just off the surface look to be in the 10 to 15 knot range. As a result, the potential for valley fog looks less. Due to this and MOS guidance showing that the temperature-dew point spreads still in the 2-4 F range at sunrise, did not include any fog or low ceilings at KLSE.
On Friday morning, high clouds will move into the TAF sites. This should occur at KRST around 24.15z and at KLSE around 24.16z.
ARX WATCHES/WARNINGS/ADVISORIES. WI . None. MN . None. IA . None.
SHORT TERM . JAR LONG TERM . Zapotocny/JAR AVIATION . Boyne
Weather Reporting StationsEDIT (on/off)  Help NOTE: Click on distance to see the station location on a map
Airport ReportsEDIT (on/off)  Help Click EDIT to display multiple airports. Follow links for more data.
|Sparta, Sparta / Fort McCoy Airport, WI||4 mi||1.9 hrs||N 0||10.00 mi||Fair||62°F||48°F||59%||1019.6 hPa|
|Black River Falls Area Airport, WI||22 mi||55 min||NNW 5||10.00 mi||Fair||67°F||44°F||43%||1017.6 hPa|
|La Crosse - La Crosse Regional Airport, WI||24 mi||57 min||N 5||10.00 mi||Fair||68°F||43°F||40%||1017.9 hPa|
Link to 5 minute data for KCMY
Wind History from CMY (wind in knots)
|1 day ago||NW||NW|
|2 days ago||S||S||SE||SE|
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