Marine Weather and Tides
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.
6/2/2019. Many thanks to a user for reporting an error on one of the Edit pages. The switch to PHP 7.2 caused many pages that previously worked to quit working. I fixed many but I still depend on users to report ones I missed. Please report errors HERE or send an email to me at L-36.com. Allen
|Sunrise 7:06AM||Sunset 4:37PM||Monday December 9, 2019 12:08 AM MST (07:08 UTC)||Moonrise 4:14PM||Moonset 5:21AM||Illumination 93%|
7 Day Forecast for Marine Location Near Castle Pines, COHourly EDIT Help
Area Discussion for - Denver/Boulder, CO  (on/off)  Help NOTE: mouseover dotted underlined text for definition
FXUS65 KBOU 090323 AFDBOU
Area Forecast Discussion National Weather Service Denver/Boulder CO 823 PM MST Sun Dec 8 2019
UPDATE. Issued at 822 PM MST Sun Dec 8 2019
Water vapor satellite imagery is showing the best lift associated with the upper level system has shifted east of the mountains across northern Colorado. This has caused the snow to decrease for most areas. Orographic lift resulting from a west to northwest flow across the mountains combined with moisture will keep light to moderate snow going through the night in the mountains. An additional 2-6 inches will be possible into Monday morning. Will keep the Winter Weather Advisory in effect for the mountains. Across the lower elevations, a cold front will bring northerly winds and low clouds after midnight. Winds decrease after the frontal passage, but low clouds will linger into Monday morning.
SHORT TERM. (This evening through Monday) Issued at 245 PM MST Sun Dec 8 2019
As the main trough axis with the current storm system pushes into northwest Colorado this afternoon, starting to see an increase in precipitation coverage across eastern UT and northwestern CO in the wake of the dry slot which was over that region earlier this morning. Observation points in this region indicate showers of light to brief moderate rain across the lower elevations with light to moderate snow coverage over the higher terrain. Forecast soundings still indicate an increase in instability through tonight as mid-level temperatures cool 7-10degC while in a saturated to near saturated environment. Strong orographic westerly flow at mountain top along with a few hours of better instability will be the main drivers through the end of the event midday monday. With these features tonight, can't rule out a few brief bursts of moderate to heavy snow overnight across the higher terrain.
With northern Colorado under the gradient of 100-120kt jet riding across the CO/NM border this afternoon, weak mid-level QG fields indicate a fairly rapid transition over to strong subsidence behind the area of best lift later tonight. Snow will begin to taper off in the high country after 12z Monday with scattered snow showers persisting over the highest terrain through late morning and afternoon as flow aloft weakens and dries out.
Across the lower elevations tonight, dry conditions and mild temperatures are expected this evening ahead of a cold front expected in the 08z-09z timeframe. With strong net westerly flow aloft there's a good chance for a few showers to pull of the higher terrain and onto the Urban Corridor this evening and overnight. At this time, forecast sounding indicate precip should be in the form of rain or rain mixed with snow tonight as the column gradually moistens. Showers that develop after the frontal passage overnight will be in the form of snow. Soundings across the lower elevations mostly fail to fully saturate below 600mb overnight. With the meager saturation, frozen precip likely won't attain best dendrite growth, while in a fairly mild airmass. Soundings hint at a possible brief period of freezing drizzle overnight initially with the frontal passage. Cross sections also indicate that precipitation tonight will be banded, so there will be the likelihood for some locations to receive up to a half in inch of snow, while other locations remain dry. The atmosphere will begin dry in the 15-18z timeframe and this trend continues through the rest of Monday with temps remaining cool.
LONG TERM. (Monday night through Sunday) Issued at 340 PM MST Sun Dec 8 2019
Moderate zonal flow Monday night gives way to strong north- northwesterly flow aloft on Tuesday. Northwesterly flow aloft decreases Tuesday night with an upper ridge moving across the CWA Wednesday. The next, weak, upper trough moves across Colorado Wednesday night. Most of its energy is south of the CWA. Downward vertical motion dominates the CWA according to the QG Omega fields Monday night through Tuesday night. Upward energy is progged Wednesday and Wednesday evening, with subsidence after midnight. The low level winds look to adhere to pretty standard normal diurnal patterns all five periods. There isn't much moisture progged in the lower and mid levels through the periods; just some in the upper levels. There is no measurable precipitation on the QPF fields. There are fairly decent winds along and east of the divide, mostly up high, but not of highlight criteria. No pops. For temperatures, Tuesday's highs are 0.5-2.5 C warmer than Monday's highs. Wednesday's highs are 1-3 C warmer than Wednesday's. For the later days, Thursday through Sunday, models have north-northwesterly flow aloft on the increase Thursday. By Friday, a strong northwesterly jet maximum is progged over Colorado. This continues through Saturday and becomes more due westerly Saturday night and Sunday. Speeds at 250 mb are in the 120-150 knot range Friday afternoon into Sunday morning. Models are showing a broad mean upper trough developing across a good portion of North America later next weekend. There is decent moisture on the cross sections through the weekend.
AVIATION. (For the 06Z TAFS through 06Z Monday night) Issued at 822 PM MST Sun Dec 8 2019
Surface winds will remain from a west to southwesterly component ahead of a cold front expected 08Z-09Z. This cold front will bring a sharp switch to northerly winds. Areas of low clouds will develop behind the front after 09Z. The best chance for seeing low clouds will be along the foothills. Where low clouds form, ceilings will fall to around 1000 feet. Low clouds will linger into mid to late morning with the clouds clearing or scattering out by 18Z.
BOU WATCHES/WARNINGS/ADVISORIES. Winter Weather Advisory until 11 AM MST Monday for COZ031-033- 034.
UPDATE . Meier SHORT TERM . Fredin LONG TERM . RJK AVIATION . Meier
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.
|Denver - Centennial Airport, CO||8 mi||75 min||WNW 15 G 25||10.00 mi||Mostly Cloudy||43°F||16°F||34%||1005.6 hPa|
|Buckley Air Force Base Airport, CO||21 mi||70 min||W 5||10.00 mi||Mostly Cloudy||39°F||17°F||42%||1005.3 hPa|
|Elbert Mountain, Monument Pass, CO||21 mi||80 min||NW 15||10.00 mi||Fair||32°F||21°F||64%||1008.1 hPa|
Link to 5 minute data for KAPA
Wind History from APA (wind in knots)
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|2 days ago||S||SE||SE||S||S||S||Calm||S||SE||SE||SW||Calm||E||SE||Calm||Calm||S||S||S||S||S||S||S||S |
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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.
Link to Loop
Other links: Northern Pacific Contential US Full GOES-East
Wind Forecast for Denver/Boulder, CO (2,6,7,8)(on/off)  Help
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