Marine Weather and Tides
8/26/2020 The 7 day forecast is taking about 5 seconds to load but it will eventually load. NOAA is still working on it.
8/18/2020 NOAA continues to have trouble. Wind guest will occasionally be left off graphs. I am working with NOAA to resolve the issue.
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 7:05AM||Sunset 4:49PM||Saturday November 28, 2020 2:30 AM CST (08:30 UTC)||Moonrise 4:02PM||Moonset 5:19AM||Illumination 96%|
7 Day Forecast for Marine Location Near Columbia, MOHourly EDIT Help
Area Discussion for - St. Louis, MO  (on/off)  Help NOTE: mouseover dotted underlined text for definition
FXUS63 KLSX 280453 AFDLSX
Area Forecast Discussion . Updated Aviation National Weather Service Saint Louis MO 1053 PM CST Fri Nov 27 2020
SHORT TERM. (Through Late Saturday Night) Issued at 240 PM CST Fri Nov 27 2020
An upper-level trough amid the northern jet stream is passing through the Great Lakes region of the CONUS. As expected, a portion of that energy near the base of the trough cut off from the main circulation and stalled across the southwestern CONUS earlier this morning. Low/mid-level cloudiness associated with a surface cold front passing through the Upper and Mid-Mississippi Valley dissipated by the early afternoon, leaving mostly clear skies and sunshine to take hold across the area today. Despite the CAA in the wake of the front, sunshine should bolster temperatures to near or slightly above-normal.
The closed low should get caught on the periphery of the southern stream across the southern CONUS and begin to slide eastward. What is interesting is how fast the closed low is modeled to move. Generally, closed circulations need upstream "kickers" to shunt them downstream, but the vorticity maxima orbiting the circulation may be propelling it forward. Winds in the lower atmosphere back to the west-southwest ahead of the low across the central Plains, but northwest flow and some semblance of CAA should stay in place overnight across our area. A broad surface ridge builds into the region this evening from the west and the resultant weakening pressure gradient will weaken winds. A clear sky, light northwest winds, and non-zero CAA aloft will keep temperatures around or slightly below freezing across the area. Fog may return to low- lying areas and river valleys tonight, but dry air should limit the extent of any fog that does develop.
Weak southerly flow finds its way back to central MO by tomorrow morning, and by early afternoon the entire CWA will be under the influence of weak return flow on the backside of the surface ridge. While weak winds within the boundary layer should not lend to any robust temperature advection, there likely will be a small temperature gradient from west to east (with warmer highs in central MO where winds back first). Other than a few high clouds in advance of the closed low (positioned in the southern Plains by this point), very dry air aloft will keep Saturday mostly clear.
High clouds stemming from the approaching closed upper-level low drawing Gulf moisture northward should overspread the bi-state area tomorrow night. Southerly BL winds and high clouds will act to warm temperatures slightly compared to the night before. By early Sunday morning, the ULL in the southern stream will begin interacting with a deepening northern stream trough entering the central CONUS from Canada. The center of the attendant surface low should be suppressed along the Gulf coast. Despite indication in the short- term deterministic guidance of an inverted surface trough bringing showers to southwestern MO Sunday morning, dry air from the incoming northern trough should hold precipitation until later in the morning and shunt the southern system east.
LONG TERM. (Sunday through Next Friday) Issued at 240 PM CST Fri Nov 27 2020
The main focus for the extended forecast centers around the chance for rain and snow across southern/eastern MO and southwestern IL early next week.
PVA and diffluent flow in the mid levels stemming from the southern stream system will override a broad area of isentropic lift in the low-level warm sector, leading to more robust upward vertical motion Sunday afternoon. While the bulk of the precipitation should remain to our southeast, showers are still possible in the southern half of the CWA Sunday afternoon north of the warm front. Boundary layer temperatures appear too warm to support snow, and the coldest air associated with the northern system will not have settled in.
Deterministic and ensemble guidance is converging on the specifics of how the upper-level closed low to our south will phase with the northern stream trough entering the area Sunday afternoon. How, when, and where they interact is crucial to what precipitation type(s) can be expected. Consensus is strong among guidance that the northern trough, bringing along considerably cold 850mb temperatures (2-4 std. dev. below climatology according to NAEFS guidance), will intercept the closed low and and shunt it to the east. In the process, the closed low tilts negatively and the constructive interference between the two disturbances will result in a much deeper upper-level trough and stronger surface low by Monday morning. Until then, the best chances for rain will follow the track of the low accordingly and slide northeast through the day into west- central IL.
By this time, the deepened surface low should be in the southern Ohio River Valley. The very cold air in place behind the system should support snow, but by that point the best forcing appears to be too far east for most of the area to receive any impactful snow. SREF guidance and deterministic models do suggest a deformation zone forming northwest of the surface low. A weak TROWAL and hints of weak frontogenesis east of the Mississippi River exist to varying degrees in deterministic and ensemble guidance, providing marginal forcing in a possibly-favorable environment for snow. Another source of uncertainty is how much of this precipitation will make it to the ground. Model soundings differ in regards to how much wetbulbing will occur late Sunday to saturate the column and allow snow to fall. Regardless, by the time evaporative cooling has a chance to prime the lower third of the atmosphere for snow, a very small window for snow actually exists before very dry air ends any precipitation chances. It appears that this event will be mostly rain, with a brief changeover to flurries or light snow in western IL.
Monday will feature unseasonably-cold high and low temperatures, struggling to reach the mid 30s and falling to the upper teens respectively amidst strong northwesterly flow. Temperatures should moderate to around normal Tuesday, however, thanks to strong downsloping upstream in the Rocky Mountains. The warmer BL temperatures that result from the adiabatic warming will act to cut off the cold air mass from its Canadian source region. Westerly flow across the western CONUS should also send a wave of warmer 850mb temperatures through the central US.
The forecast beyond Tuesday becomes incredibly uncertain. While guidance agrees on the presence of a broad longwave trough across the eastern two-thirds of the CONUS, several shortwaves and cutoff lows pass through and interact with each other. There are hints that another robust system will pass through the CWA sometime late in the week, but timing, positional, and intensity differences are still massive. Attention for this forecast was given to the more imminent storm, so the National Blend of Models output was left untouched for precipitation chances late in the period.
AVIATION. (For the 06z TAFs through 06z Saturday Night) Issued at 1052 PM CST Fri Nov 27 2020
Patchy radiation fog could develop late tonight at KSUS and KCPS with MVFR flight conditions possible. Any fog should mix out by mid- Saturday morning. Otherwise, prevailing VFR flight conditions are anticipated across all terminals through the end of the period with only upper-level clouds entering the area Saturday night.
LSX WATCHES/WARNINGS/ADVISORIES. MO . None. IL . None.
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.
|Columbia, Columbia Regional Airport, MO||8 mi||37 min||W 6||9.00 mi||Fair||36°F||28°F||76%||1024.6 hPa|
|Jesse Viertel Memorial Airport, MO||21 mi||36 min||N 0||10.00 mi||Fair||33°F||32°F||99%||1024.7 hPa|
|Jefferson City, Jefferson City Memorial Airport, MO||24 mi||38 min||N 0||10.00 mi||Fair||33°F||28°F||85%||1024.4 hPa|
Link to 5 minute data for KCOU
Wind History from COU (wind in knots)
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|2 days ago||SE||E||E||SE||SE||SE||Calm||S||W|
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