Marine Weather and Tide Forecast for Brighton, CO
March 29, 2024 6:04 AM MDT (12:04 UTC) Change Location
Sunrise 6:45 AM Sunset 7:22 PM Moonrise 12:00 AM Moonset 8:41 AM |
Area Discussion for - Denver/Boulder, CO
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FXUS65 KBOU 291034 AFDBOU
Area Forecast Discussion National Weather Service Denver/Boulder CO 434 AM MDT Fri Mar 29 2024
KEY MESSAGES
- Accumulating snow and minor travel impacts across the northern mountains through Friday night. More significant accumulations in the Rabbit Ears Pass and Park Range, and lighter accumulations in the I-70 Mountain Corridor.
- A few showers spill onto the plains today and tonight.
- Next storm system late Sunday into Monday night with mountain snow, and a mix of rain and snow likely for the plains. Mostly light precipitation amounts are expected but there could be some travel impacts for the mountains and higher elevation foothills.
SHORT TERM /Through tonight/
Issued at 434 AM MDT Fri Mar 29 2024
Well, we've been fiddling with trying to pin down the details of shortwaves riding along the weak mid level front west and north of Denver, and sure enough the result today isn't exactly what was expected. The showers are 6-8 hours late and it looks like they're going to be about 50 miles further south too. This means the best mountain snow from this round is happening now through about mid morning, and there will be a chance of showers on the plains that will probably start late this morning north of Denver, and a bit more of a chance around Denver this afternoon. The best lift might be in the middle of the day so not perfect timing to tap diurnal instability. Low levels on the plains remain dry, though cooler highs from the extra cloud cover will reduce evaporation a bit. So we'll stick with scattered PoPs on the plains due to evaporation. So the main adjustments for today were to raise/shift southward the PoPs, add clouds, and cool highs a couple of degrees.
For tonight there's another ripple in the jet producing a wave riding along that mid level front. Current expectations are that this will run a bit further north, but we'll see how that goes. In any event, it will keep showers going in the mountains with some chance of rain on the plains mainly north of Denver. Temperatures may bottom out close to freezing on the plains, but the snow level should stay above 6000 feet and probably closer to 7000.
LONG TERM /Saturday through Thursday/
Issued at 434 AM MDT Fri Mar 29 2024
On Saturday, moist southwest flow aloft continues with a potent trough just off the West Coast of the U.S. The moisture plume and upslope flow, combined with steep lapse rates, should result in light snow during the day, mostly across the Park Range and northern Front Range. The I-70 mountain corridor doesn't look great for accumulating snow given the less favorable wind direction and the best moisture remaining to the north. One thing to mention is the Euro ensembles crank out a tenth or two across the plains of Colorado during the late morning hours into early afternoon. This is a new development and we are scratching our heads how this is possible with significant downslope flow at 700 mb. There is some convective instability during the afternoon but low levels look too dry for much accumulation, so for now we are discounting the Euro model/ensembles for Saturday. However, along the Wyoming border PoPs will remain in the 20-40 percent range given the influence of the 120 kt jet overhead. There isn't any cold air around to generate snow below 6 kft in the morning, and with the near-April sun angle and warming temps, snow levels rise to around 8 kft by mid-afternoon. Travel impacts are expected to be limited on Saturday during the day due to the sun angle and light precipitation rates, even across Rabbit Ears Pass where a couple inches could fall, but the roads will most likely be wet into the early evening hours. Temperatures across the plains and urban corridor should reach the mid 60s, while the mountain valleys should be in the 40s.
On Sunday the West Coast trough splits into two, with one trough moving across the Great Basin, and the other diving south and remaining offshore of SoCal. Moisture in southwest flow, combined with lapse rates, should continue the light snow across the mountains and northward along the Wyoming border. There is better QG lift and overall moisture that there should be a little more snow falling across the higher elevations, this time extending further south to the I-70 mountain corridor but still not all the way into South Park. Temperatures Sunday will be similar to Saturday, limiting the impacts to travel during the day, even across the higher passes, but by Sunday afternoon convective instability is introduced and brief moderate snow may occur, and if it occurs late enough in the day slush/slick spots are possible across the mountain roads Sunday afternoon/evening. Several inches of snow are expected on Sunday along and north of I-70, especially above 9,000 ft. The previously mentioned jet and QG lift traverses the Wyoming border Sunday evening, increasing rain chances for the norther tier of Colorado Counties. Snow levels should remain above 6 kft once again while it is precipitating, but can't rule out a late change over with light snow by sunrise right along the border. Elsewhere across the I-25 corridor, light showers are possible (15-40 percent) but for now it looks too warm for snow, and precip accumulations should be light through Monday morning.
Temperatures Sunday should again be in the 60s across the Plains, and maybe even 70s across Lincoln County where much less cloud cover should exist. There will be strong southwest winds gusting 30-35 mph during the afternoon, deep mixing across the far eastern plains of Colorado, and combined with RH dropping below 15%, we may need fire wx highlights for Lincoln County and maybe Washington County too. It's too early and marginal to issue anything just yet.
Forecast uncertainty increases with Monday's forecast, and I would be a fool if I was confident in what will happen at this stage of the game. Deterministic models and their ensemble output continue to be all over the place with the evolution of the cut off low ejecting east across the area, and thus with QPF and snow.
There are a few aspects of the forecast that at least seem to be a little more certain. One is a cold front. All models/ensembles have a pretty good cold front moving south across the plains, and a strong connection to a 700 mb front moving southeast across the mountains too. EC and members are quicker and weaker with the front, while GFS and members bring it through late morning Monday and it packs a punch. 700 mb temps drop to -10 degC and surface wet bulb temps drop below freezing by mid afternoon if not sooner.
There is also significant frontogenesis associated with the front as it sweeps across the plains, if you believe the GFS and some of it's ensemble members. Upslope potential across the east slopes is limited in the GFS with a deepening surface cyclone and 700 mb low across the NE panhandle. That results in strong northwest winds. However, the GEFS has several members crank out a bunch of QPF due to instability and frontogenesis. Every single member has some precip for the plains and urban corridor, and about half are cold enough for snow. The EC ensemble system on the other hand, despite it not deepening a surface cyclone and 700 mb cut off trough like the GEFS, has a better upslope component to the low level winds, and also has plenty of instability but less cold air and a weaker frontal passage. Every member of the EC also generates precipitation across the I-25 corridor and eastern plains. Snow accumulation across the lower elevations (below 6,500 ft) is not out of the question, though it's less likely with the EC ensembles. Instability is going to be the wild card here, because the synoptic/mesoscale pattern just doesn't look favorable for more than light QPF totals. With marginal temperatures and April sun angle, travel impacts should be limited to Monday evening and only with the higher elevation roadways, especially above 8 kft across the east slopes.
Aside from very low confidence in Monday's weather, confidence increases once again from Tuesday morning onward. It looks dry across the area with a rapid warming trend, going from the 50s Tuesday to near 70 on Wednesday, and over 70 on Thursday across the plains and I-25 corridor. Even the mountain valleys will see a significant warming trend, with temperatures going from the 40s on Tuesday to the low 50s the rest of the week. The NBM forecast looked reasonable after Monday next week.
AVIATION /06Z TAFS through 06Z Friday/
Issued at 1240 AM MDT Fri Mar 29 2024
VFR through Friday. There will be some variability in the light winds overnight, but S to SE winds should prevail at KDEN/KAPA.
More uncertainty at KBJC which may be on the edge of west winds coming off the foothills at around 10 knots and lighter southeast winds. A shift to northeast winds is expected between 10z-12z.
Isolated rain showers are expected after 18z, but ceilings are generally expected to remain above 6000 ft.
BOU WATCHES/WARNINGS/ADVISORIES
Winter Weather Advisory until 6 AM MDT Saturday for COZ031.
Area Forecast Discussion National Weather Service Denver/Boulder CO 434 AM MDT Fri Mar 29 2024
KEY MESSAGES
- Accumulating snow and minor travel impacts across the northern mountains through Friday night. More significant accumulations in the Rabbit Ears Pass and Park Range, and lighter accumulations in the I-70 Mountain Corridor.
- A few showers spill onto the plains today and tonight.
- Next storm system late Sunday into Monday night with mountain snow, and a mix of rain and snow likely for the plains. Mostly light precipitation amounts are expected but there could be some travel impacts for the mountains and higher elevation foothills.
SHORT TERM /Through tonight/
Issued at 434 AM MDT Fri Mar 29 2024
Well, we've been fiddling with trying to pin down the details of shortwaves riding along the weak mid level front west and north of Denver, and sure enough the result today isn't exactly what was expected. The showers are 6-8 hours late and it looks like they're going to be about 50 miles further south too. This means the best mountain snow from this round is happening now through about mid morning, and there will be a chance of showers on the plains that will probably start late this morning north of Denver, and a bit more of a chance around Denver this afternoon. The best lift might be in the middle of the day so not perfect timing to tap diurnal instability. Low levels on the plains remain dry, though cooler highs from the extra cloud cover will reduce evaporation a bit. So we'll stick with scattered PoPs on the plains due to evaporation. So the main adjustments for today were to raise/shift southward the PoPs, add clouds, and cool highs a couple of degrees.
For tonight there's another ripple in the jet producing a wave riding along that mid level front. Current expectations are that this will run a bit further north, but we'll see how that goes. In any event, it will keep showers going in the mountains with some chance of rain on the plains mainly north of Denver. Temperatures may bottom out close to freezing on the plains, but the snow level should stay above 6000 feet and probably closer to 7000.
LONG TERM /Saturday through Thursday/
Issued at 434 AM MDT Fri Mar 29 2024
On Saturday, moist southwest flow aloft continues with a potent trough just off the West Coast of the U.S. The moisture plume and upslope flow, combined with steep lapse rates, should result in light snow during the day, mostly across the Park Range and northern Front Range. The I-70 mountain corridor doesn't look great for accumulating snow given the less favorable wind direction and the best moisture remaining to the north. One thing to mention is the Euro ensembles crank out a tenth or two across the plains of Colorado during the late morning hours into early afternoon. This is a new development and we are scratching our heads how this is possible with significant downslope flow at 700 mb. There is some convective instability during the afternoon but low levels look too dry for much accumulation, so for now we are discounting the Euro model/ensembles for Saturday. However, along the Wyoming border PoPs will remain in the 20-40 percent range given the influence of the 120 kt jet overhead. There isn't any cold air around to generate snow below 6 kft in the morning, and with the near-April sun angle and warming temps, snow levels rise to around 8 kft by mid-afternoon. Travel impacts are expected to be limited on Saturday during the day due to the sun angle and light precipitation rates, even across Rabbit Ears Pass where a couple inches could fall, but the roads will most likely be wet into the early evening hours. Temperatures across the plains and urban corridor should reach the mid 60s, while the mountain valleys should be in the 40s.
On Sunday the West Coast trough splits into two, with one trough moving across the Great Basin, and the other diving south and remaining offshore of SoCal. Moisture in southwest flow, combined with lapse rates, should continue the light snow across the mountains and northward along the Wyoming border. There is better QG lift and overall moisture that there should be a little more snow falling across the higher elevations, this time extending further south to the I-70 mountain corridor but still not all the way into South Park. Temperatures Sunday will be similar to Saturday, limiting the impacts to travel during the day, even across the higher passes, but by Sunday afternoon convective instability is introduced and brief moderate snow may occur, and if it occurs late enough in the day slush/slick spots are possible across the mountain roads Sunday afternoon/evening. Several inches of snow are expected on Sunday along and north of I-70, especially above 9,000 ft. The previously mentioned jet and QG lift traverses the Wyoming border Sunday evening, increasing rain chances for the norther tier of Colorado Counties. Snow levels should remain above 6 kft once again while it is precipitating, but can't rule out a late change over with light snow by sunrise right along the border. Elsewhere across the I-25 corridor, light showers are possible (15-40 percent) but for now it looks too warm for snow, and precip accumulations should be light through Monday morning.
Temperatures Sunday should again be in the 60s across the Plains, and maybe even 70s across Lincoln County where much less cloud cover should exist. There will be strong southwest winds gusting 30-35 mph during the afternoon, deep mixing across the far eastern plains of Colorado, and combined with RH dropping below 15%, we may need fire wx highlights for Lincoln County and maybe Washington County too. It's too early and marginal to issue anything just yet.
Forecast uncertainty increases with Monday's forecast, and I would be a fool if I was confident in what will happen at this stage of the game. Deterministic models and their ensemble output continue to be all over the place with the evolution of the cut off low ejecting east across the area, and thus with QPF and snow.
There are a few aspects of the forecast that at least seem to be a little more certain. One is a cold front. All models/ensembles have a pretty good cold front moving south across the plains, and a strong connection to a 700 mb front moving southeast across the mountains too. EC and members are quicker and weaker with the front, while GFS and members bring it through late morning Monday and it packs a punch. 700 mb temps drop to -10 degC and surface wet bulb temps drop below freezing by mid afternoon if not sooner.
There is also significant frontogenesis associated with the front as it sweeps across the plains, if you believe the GFS and some of it's ensemble members. Upslope potential across the east slopes is limited in the GFS with a deepening surface cyclone and 700 mb low across the NE panhandle. That results in strong northwest winds. However, the GEFS has several members crank out a bunch of QPF due to instability and frontogenesis. Every single member has some precip for the plains and urban corridor, and about half are cold enough for snow. The EC ensemble system on the other hand, despite it not deepening a surface cyclone and 700 mb cut off trough like the GEFS, has a better upslope component to the low level winds, and also has plenty of instability but less cold air and a weaker frontal passage. Every member of the EC also generates precipitation across the I-25 corridor and eastern plains. Snow accumulation across the lower elevations (below 6,500 ft) is not out of the question, though it's less likely with the EC ensembles. Instability is going to be the wild card here, because the synoptic/mesoscale pattern just doesn't look favorable for more than light QPF totals. With marginal temperatures and April sun angle, travel impacts should be limited to Monday evening and only with the higher elevation roadways, especially above 8 kft across the east slopes.
Aside from very low confidence in Monday's weather, confidence increases once again from Tuesday morning onward. It looks dry across the area with a rapid warming trend, going from the 50s Tuesday to near 70 on Wednesday, and over 70 on Thursday across the plains and I-25 corridor. Even the mountain valleys will see a significant warming trend, with temperatures going from the 40s on Tuesday to the low 50s the rest of the week. The NBM forecast looked reasonable after Monday next week.
AVIATION /06Z TAFS through 06Z Friday/
Issued at 1240 AM MDT Fri Mar 29 2024
VFR through Friday. There will be some variability in the light winds overnight, but S to SE winds should prevail at KDEN/KAPA.
More uncertainty at KBJC which may be on the edge of west winds coming off the foothills at around 10 knots and lighter southeast winds. A shift to northeast winds is expected between 10z-12z.
Isolated rain showers are expected after 18z, but ceilings are generally expected to remain above 6000 ft.
BOU WATCHES/WARNINGS/ADVISORIES
Winter Weather Advisory until 6 AM MDT Saturday for COZ031.
Airport Reports
EDIT (hide/show)  Help Click EDIT to display multiple airports. Follow links for more data.Airport | Dist | Age | Wind kt | Vis | Sky | Weather | Temp | DewPt | RH | inHg |
KDEN DENVER INTL,CO | 7 sm | 71 min | NE 10 | 10 sm | Mostly Cloudy | 37°F | 27°F | 65% | 29.77 | |
KCFO COLORADO AIR AND SPACE PORT,CO | 16 sm | 29 min | E 09 | 10 sm | Clear | 37°F | 25°F | 60% | 29.80 | |
KEIK ERIE MUNI,CO | 16 sm | 29 min | SW 04 | 10 sm | A Few Clouds | 36°F | 28°F | 75% | 29.80 | |
KBKF BUCKLEY AFB,CO | 17 sm | 66 min | ENE 07 | 10 sm | Mostly Cloudy | 39°F | 23°F | 52% | 29.76 | |
KBJC ROCKY MOUNTAIN METROPOLITAN,CO | 19 sm | 29 min | NNE 03 | 10 sm | Clear | 39°F | 28°F | 65% | 29.81 |
Denver/Boulder, CO,
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