Marine Weather and Tide Forecast for Calhan, CO
May 17, 2024 8:26 PM MDT (02:26 UTC) Change Location
 | Sunrise 5:42 AM Sunset 8:08 PM Moonrise 2:36 PM Moonset 2:54 AM |
Area Discussion for - Denver/Boulder, CO
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FXUS65 KBOU 172059 AFDBOU
Area Forecast Discussion National Weather Service Denver/Boulder CO 259 PM MDT Fri May 17 2024
KEY MESSAGES
- Warm through Sunday. Isolated to scattered high based showers and storms this evening, and then again Saturday.
- Breezier Sunday into Monday.
- Cooler, unsettled pattern with increasing precipitation chances across the region early next week.
SHORT TERM /Through Saturday/
Issued at 259 PM MDT Fri May 17 2024
Satellite shows shallow cumulus developing across the area. There is a little deeper growth noted over northwest Colorado, with a few showers starting to develop. With just enough destabilization but dry low levels, we expect isolated to scattered high based light showers/sprinkles in the high country/northern border area through this evening, with only a rumble or two of thunder possible. The rest of the plains and I-25 Corridor will only see some virga, but can't rule out some gusty outflow winds due to well mixed and relatively deep sub-cloud layer.
On Saturday, both moisture and instability build a little more with a weak shortwave noted in the QG fields. At the surface, a weak cold front backdoors across the plains late tonight/early Saturday morning. There is slight cooling noted in the boundary layer, but enough daytime heating still expected to weaken the cap and allow scattered showers/storms in the mountains to eventually spread onto part of the plains late in the afternoon. There is a little more MLCAPE with 200-400 J/kg noted, so expect a few more lightning strikes and rumbles of thunder. The most favored locations would stay generally south of I-76. Temperatures should be a few degrees cooler behind the front, but still a few degrees above normal. Southeast breezes will increase through the afternoon.
LONG TERM /Saturday night through Friday/
Issued at 259 PM MDT Fri May 17 2024
Scattered showers and thunderstorms should continue along areas south of Denver Saturday evening. It is likely areas will lack instability especially after the front thus leading to weak high based showers spreading into the plains through southerly flow until Sunday night. Low temperatures range between 45-55F for the Palmer Divide and plains. For the higher elevations, temperatures drop between 30-39F. Partly cloudy skies persist through Sunday.
Cross sections display drier air and weak mid-level moisture mainly in the high country Sunday. Zonal flow will increase resulting in wind gusts up to 25-35 mph for foothills below timberline through Sunday afternoon. NBM retains too much PoPs for weak mid-level moisture afternoon for the foothills and plains thus this forecast update reduced PoPs for likely (35-50%)chances of showers mainly in Jackson and northern Larimer counties.
Expect light rain and gusty winds up to 40-45 mph if a shower collapses.
High uncertainty lingers for Monday night and Tuesday synoptic pattern. 500mb heights across ensembles favor a shortwave trough entering no eastern Colorado mainly Monday through Tuesday. ECMWF seems to favor a less robust system with an open broad trough sweeping north of our region while the GFS favors a deeper trough entering the western mountains then pushing into the center of our CWA Timing seems to be delayed where majority of this system occurs Tuesday. Given this pattern, it is possible PoPs may have to be reduced Monday afternoon. Higher confidence remains in the general outcome of numerous showers and storms Monday night into Tuesday late morning. This pattern would likely lead to impacts such as brief heavy rainfall and small hail. Additionally, cooler temperatures are possible each afternoon Tuesday and Wednesday.
Overall, this cool down seems short lived as temperatures bounce back near normal Thursday.
AVIATION /18Z TAFS through 18Z Saturday/
Issued at 1153 AM MDT Fri May 17 2024
VFR through the TAF period. Winds will be the biggest challenge as usual. We're already seeing signs of channeling of west winds, which means some places will see northerly or even light easterly winds, while others in the channels will see gusts to 20-25 knots through the afternoon. We'll mention some of this variability in the TAFs for now, but then shoot for more dominating WNW winds after 21Z with further mixing. Some virga is also possible which could bring a few VRB gusts to 30-35 knots (20-30% chance) given the deep and well mixed sub-cloud layer.
Winds are expected to weaken again by about 02Z, and then return to fairly normal south/southwest flow. A weak cold front will try to push towards the terminals overnight with a shift to the north or northeast possible after 10Z, but there are equal odds of just variable winds until a stronger anticyclone develops 12Z-18Z with an increase in southeast winds to 10-15 knots. Southeast winds will likely strengthen further on Saturday afternoon with gusts upward of 25 knots possible. Isolated to scattered high based showers/storms will develop late in the afternoon and evening, warranting a PROB30 of VRB gusty winds and -TSRA after ~22Z.
BOU WATCHES/WARNINGS/ADVISORIES
None.
Area Forecast Discussion National Weather Service Denver/Boulder CO 259 PM MDT Fri May 17 2024
KEY MESSAGES
- Warm through Sunday. Isolated to scattered high based showers and storms this evening, and then again Saturday.
- Breezier Sunday into Monday.
- Cooler, unsettled pattern with increasing precipitation chances across the region early next week.
SHORT TERM /Through Saturday/
Issued at 259 PM MDT Fri May 17 2024
Satellite shows shallow cumulus developing across the area. There is a little deeper growth noted over northwest Colorado, with a few showers starting to develop. With just enough destabilization but dry low levels, we expect isolated to scattered high based light showers/sprinkles in the high country/northern border area through this evening, with only a rumble or two of thunder possible. The rest of the plains and I-25 Corridor will only see some virga, but can't rule out some gusty outflow winds due to well mixed and relatively deep sub-cloud layer.
On Saturday, both moisture and instability build a little more with a weak shortwave noted in the QG fields. At the surface, a weak cold front backdoors across the plains late tonight/early Saturday morning. There is slight cooling noted in the boundary layer, but enough daytime heating still expected to weaken the cap and allow scattered showers/storms in the mountains to eventually spread onto part of the plains late in the afternoon. There is a little more MLCAPE with 200-400 J/kg noted, so expect a few more lightning strikes and rumbles of thunder. The most favored locations would stay generally south of I-76. Temperatures should be a few degrees cooler behind the front, but still a few degrees above normal. Southeast breezes will increase through the afternoon.
LONG TERM /Saturday night through Friday/
Issued at 259 PM MDT Fri May 17 2024
Scattered showers and thunderstorms should continue along areas south of Denver Saturday evening. It is likely areas will lack instability especially after the front thus leading to weak high based showers spreading into the plains through southerly flow until Sunday night. Low temperatures range between 45-55F for the Palmer Divide and plains. For the higher elevations, temperatures drop between 30-39F. Partly cloudy skies persist through Sunday.
Cross sections display drier air and weak mid-level moisture mainly in the high country Sunday. Zonal flow will increase resulting in wind gusts up to 25-35 mph for foothills below timberline through Sunday afternoon. NBM retains too much PoPs for weak mid-level moisture afternoon for the foothills and plains thus this forecast update reduced PoPs for likely (35-50%)chances of showers mainly in Jackson and northern Larimer counties.
Expect light rain and gusty winds up to 40-45 mph if a shower collapses.
High uncertainty lingers for Monday night and Tuesday synoptic pattern. 500mb heights across ensembles favor a shortwave trough entering no eastern Colorado mainly Monday through Tuesday. ECMWF seems to favor a less robust system with an open broad trough sweeping north of our region while the GFS favors a deeper trough entering the western mountains then pushing into the center of our CWA Timing seems to be delayed where majority of this system occurs Tuesday. Given this pattern, it is possible PoPs may have to be reduced Monday afternoon. Higher confidence remains in the general outcome of numerous showers and storms Monday night into Tuesday late morning. This pattern would likely lead to impacts such as brief heavy rainfall and small hail. Additionally, cooler temperatures are possible each afternoon Tuesday and Wednesday.
Overall, this cool down seems short lived as temperatures bounce back near normal Thursday.
AVIATION /18Z TAFS through 18Z Saturday/
Issued at 1153 AM MDT Fri May 17 2024
VFR through the TAF period. Winds will be the biggest challenge as usual. We're already seeing signs of channeling of west winds, which means some places will see northerly or even light easterly winds, while others in the channels will see gusts to 20-25 knots through the afternoon. We'll mention some of this variability in the TAFs for now, but then shoot for more dominating WNW winds after 21Z with further mixing. Some virga is also possible which could bring a few VRB gusts to 30-35 knots (20-30% chance) given the deep and well mixed sub-cloud layer.
Winds are expected to weaken again by about 02Z, and then return to fairly normal south/southwest flow. A weak cold front will try to push towards the terminals overnight with a shift to the north or northeast possible after 10Z, but there are equal odds of just variable winds until a stronger anticyclone develops 12Z-18Z with an increase in southeast winds to 10-15 knots. Southeast winds will likely strengthen further on Saturday afternoon with gusts upward of 25 knots possible. Isolated to scattered high based showers/storms will develop late in the afternoon and evening, warranting a PROB30 of VRB gusty winds and -TSRA after ~22Z.
BOU WATCHES/WARNINGS/ADVISORIES
None.
Pueblo, CO,
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