Saturday, March17, 2018

Marine Weather and Tides
Holly Hills, CO

Version 3.4
What's New / NOTES
3/3/2018 - There is a new GOES Satellite for the east coast that required rewriting that part of the code. Please report any issues.
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.

Sunrise 7:05AMSunset 7:10PM Saturday March 17, 2018 10:25 AM MDT (16:25 UTC) Moonrise 7:30AMMoonset 7:29PM Illumination 1% Phase: New Moon; Moon at 1 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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7 Day Forecast for Marine Location Near Holly Hills, CO
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location: 39.71, -104.95     debug

Area Discussion for - Denver/Boulder, CO
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Fxus65 kbou 171001
area forecast discussion
national weather service denver boulder co
401 am mdt Sat mar 17 2018

Short term (today and tonight)
issued at 400 am mdt Sat mar 17 2018
sw flow aloft will be over the area through tonight as an upper
level trough is over the WRN us. Cross-sections show some mid
and higher level moisture embedded in the flow, however, lower
levels will remain dry. At this time will only mention low pops
over zn 31 late tonight with dry conditions elsewhere. Meanwhile
with sfc low pres developing along the front range will see gusty
southerly winds by early aftn across the plains. As far as highs,
readings will be in the upper 50s to mid 60s across nern co except
over the far nern corner where highs may only reach the lower

Long term (Sunday through Friday)
issued at 400 am mdt Sat mar 17 2018

Snow expected for much of the forecast area by Sunday

satellite analysis shows one significant shortwave associated with
the western u.S. Trough lifting northward into idaho early this
morning, while the next piece of energy was just beginning to
organize off the central california coast. This wave will move
inland today and be our weather maker starting Sunday afternoon
and Sunday evening.

Sunday will start off rather mild with warm and relatively dry southwest
flow aloft across the forecast area. We should see a fair amount
of sunshine with such southerly flow ahead of the deepening
trough. Moderate to strong surface pressure falls will occur ahead
of this system with daytime heating and increasing q-g lift. At
this time, expect the main surface low pressure system to
organize over southeast colorado Sunday afternoon, and then push
into southwest kansas or the ok tx panhandle region by Monday
evening. This is where the forecast gets tricky.

There are still a few model runs including the ec and canadian
which take the low and mid level circulation center a bit farther
south than the GFS and nam. That farther south solution would
keep the deeper and stronger upslope flow away from the front
range, with a more northerly component expected. However, even the
farther north GFS and NAM have a short-lived upslope event, and
also keep the developing trowal (trough of warm air aloft) farther
east across the plains. At this time, it looks like the bulk of
the precipitation across the mountains will be convectively
induced, starting Saturday afternoon and continuing into the
evening. As a result, most of the snowfall amounts are expected
to be in the advisory criteria, unless the location and intensity
of the upper low are off (and we'll need to monitor this today as
the main upper disturbance moves onshore). Then, we could still be
looking at more significant precipitation across the front range
mountains and foothills. At this time, we have pretty good
confidence for a moderate snow event of 4-10 inches across the
front range mountains and foothills, with locally higher amounts
possible due to convective bursts tomorrow afternoon early
evening. We could even see some thundersnow with a couple hundred
joules of CAPE and synoptic lift in play during peak daytime
heating. Will continue to adjust these amounts as necessary.

On the plains, the tricky forecast is in play here as well given
marginal temperature profile, convective nature, and position of
eventual trowal. We do think the convective character and heavier
precipitation rates will lend itself to a quicker changeover to
snow Sunday evening, and a difference of an hour or two could lend
itself to big changes in the total accumulation forecast. At this
time, the most likely scenario is for rain to change over to snow
by mid evening along the i-25 corridor, and across the eastern
plains after midnight. If that occurs, then we'd be looking at
1-3" of snow (outside of the strong downslope areas like greeley),
and up to 4-8" over the palmer divide. If the changeover occurs
just an hour or two earlier, then we could easily add on a couple
more inches in denver. The palmer divide is where the most concern
is now for solid winter weather advisory numbers, if not higher.

For now confidence is still not high enough in any of our
forecast area for a winter storm watch, and will let the later
shifts to see how the upper low track and confidence in any given
scenario plays out.

Snow will taper off and end from west to east across the plains
later Sunday night into Monday morning. Behind that, look for
scattered lighter snow showers to linger - mostly in the
mountains. Winds will become quite gusty across the plains in the
wake of the deepening surface low, with gusts of 35-45 mph Sunday
night through Monday. This may produce some blowing drifting in
areas that see colder temperatures and more snow (palmer divide).

Beyond that, upper level ridging and warming temperatures will
take hold for Tuesday and Wednesday. Then the next system which
has some subtropical characteristics to it will bring a return of
some wet but mainly light snow in warm neutral temp advection
Thursday into Friday. Plains should stay mostly dry through this

Aviation (for the 06z tafs through 06z Saturday night)
issued at 400 am mdt Sat mar 17 2018
a denver cyclone will develop by early aftn to the southwest of dia
with a convergence zone across the metro area. South winds early
this morning may become light west or southwest by 15z and then
transition to more northeast by midday. By 21z southerly winds may
move across the airport as boundary lifts north. If cyclone
becomes well defined could see a few hours of sustained winds in
the 15 to 20 mph range with higher gusts. By early evening denver
cyclone may move to the east northeast of dia with a northwest
wind shift for a few hours. By midnight winds will transition back
to drainage.

Fire weather
Issued at 400 am mdt Sat mar 17 2018
fire danger will become elevated over the palmer divide and across
lincoln county this afternoon as humidity levels drop down to 15%.

South winds of 15 to 20 mph will develop with a few gusts up to 25
mph at times.

Fire danger will be elevated again on Sunday across elbert and
lincoln counties where southerly winds gusting to 25 mph and rh
will drop under 15%.

Bou watches warnings advisories

Short term... Rpk
long term... Barjenbruch
aviation... Rpk
fire weather... Rpk barjenbruch

Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Buckley Air Force Base Airport, CO11 mi28 minSSW 1210.00 miFair49°F24°F38%1010.4 hPa
Denver - Centennial Airport, CO12 mi33 minS 1510.00 miA Few Clouds46°F25°F44%1011.2 hPa
Broomfield / Jeffco, CO16 mi41 minN 030.00 miClear41°F15°F36%1012.2 hPa
Denver, Denver International Airport, CO18 mi33 minSW 510.00 miA Few Clouds47°F27°F46%1010.5 hPa
Erie Municipal Airport, CO21 mi26 minN 010.00 miFair40°F16°F38%1014.2 hPa
Denver Nexrad, CO22 mi88 minS 1410.00 miA Few Clouds46°F26°F46%1012.5 hPa

Wind History from BKF (wind in knots)
Last 24hrW10W15
1 day agoW5W3NE10N14
2 days agoS7CalmCalmSW4S5SE4E9E9SE9SE12SE10S11S9S13S13S13SW11S10NE4N6CalmS7S4N3

Tide / Current Tables for
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Weather Map and Satellite Images
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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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Wind Forecast for Denver/Boulder, CO (12,3,4,5)
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Ground Weather Radar Station Denver/Boulder, CO
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The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerious of sources and is presented automatically. It is not checked for accuracy either by anyone at or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.