wxgeek's weather-Precip and Flood forecast-Update 5/8

Update May 9th

The grand finale will be on display today and tonight across our state. Upper low currently located just west of the 4 Corners, and is forecast to track east northeast through the day into southeast CO then turn northerly into northeast CO by Sunday morning. The proximity of the low will create a southeasterly flow aloft today, turning to easterly this evening then northeasterly tonight. A very active and dangerous weather day and night ahead for many in our state.

Rain, showers and thunderstorms persisted overnight across much of the state into this morning. Lots of flood advisories, watches and warning exists from the foothills into the plains. Precip will intensify through the day today as upper low tracks closer, with severe thunderstorms possible mostly east of I-25. Snow level will hang around 8000-9000 ft today with little accumulation expected below 9000 ft. Snow level will begin to lower by late this afternoon and evening down to 7000-8000 ft as heavy precip continues, so snow will begin to accumulate above 8000 ft after about 4-6 pm. Moderate to heavy precip will continue overnight, with snow level lowering to 5000-6000 ft after midnight. Areas below 7000 ft will see a dusting to a few inches of accumulation, mostly on grassy surfaces. Areas above 8000 ft in the foothills will see from 3-8 inches of snow, with higher elevations seeing up to a foot of snow by Sunday morning. NWS has issued a Winter Storm Watch for the foothills, while a Winter Storm Warning is in efect for mountain areas above 9000 ft for 8-16 inches of snow. Flooding will become a major issue during the day and overnight as many streams and rivers are expected to crest above flood stage, so prone areas will have minor to moderate flooding. If you live in such an area, stay very alert today and tonight and be prepared for immediate evacuations. Roads may become snow and ice packed above 8000 ft tonight into Sunday morning, so be prepared for winter driving conditions.

Good day and night to hunker down if you do not need to be out and about. Precip will diminish by Sunday morning and become showery the remainder of the day, with temps well below seasonal norms and snow level in the 7000-8000 ft range.

Next week continues to look drier and warmer with only isolated afternoon and evening showers and thundrestorms with temps at or above seasonal norms, and snow level above 12,000 ft.

The central and southern plains are also expecting a very active severe weather day today, so if traveling in this area, stay alert for severe weather with damaging tornadoes possible.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

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Nope, this is not normal CO weather for May, or any other time of year for that matter. 8 consecutive days of rain in May, and 3 more to go. Just keep reminding yourself it is better than fires everywhere, I think.

Another wet day ahead. Upper low currently spinning across southeast CA this morning, with a very moist southerly flow in place across CO. Showers have persisted overnight in may areas, and will increase in coverage and intensity through the day. Atmosphere unstable enough to support thunderstorms with the chance for some to become severe again today mostly along and east of I-25. Snow level looks to remain in the 9000-10,000 ft range today.

For Saturday, upper low is forecast to move near the 4 Corners region by morning and track into southeast CO by evening, then into northeast CO by Sunday morning. Models suggest more precip possible overnight Friday night, but we may see a slight break in precip Saturday morning, before the wild weather cranks up. By Saturday afternoon with upper low closer, more upslope flow and some cooler air aloft, precip will become widespread and the threat of severe storms will again be possible across eastern CO. Snow level looks to remain around 9000 ft during the day, but begins to lower to 8000 ft by late Saturday afternoon, then lowers to near plains level by midnight. Models suggest some very heavy precip from Saturday afternoon into Sunday morning east of the Divide. Some areas could see 1-2 inches of liquid equivalent in this 18 hour period. NWS has a Winter Storm Watch in place for mountain areas above 9000 ft, including the Front Range mountains for 10-20 inches of snow. I believe this will become a Warning today, and NWS may have to issue some winter type advisory to include foothill areas above 8000 ft as well. Still difficult to determine how much snow will accumulate in foothills areas, but with so much precip possible and snow level lowering below 8000 ft by late Saturday afternoon, higher foothills areas could see significant accumulations. Forecast of 2-6 inches still reasonable above 8000 ft, but I could see some areas above 9000 ft getting up to a foot of snow by Sunday morning, so some roads could be become slick at higher elevations Saturday night into Sunday morning. Models suggest showery type precip on Mothers Day with temps remaining well below seasonal norms, and snow level lingering in the 7000-8000 ft range. Gusty northerly winds may also be present Sunday, especially east of I-25.

With many streams and rivers already close to flood stage, weekend rain may push many beyond flood stage, so if you live in a flood prone area, stay alert for flood messages and warnings today through Sunday.

Next week still looks drier and warmer. Isolated afternoon and evening showers and thunderstorms will be possible, especially with all the surface moisture from this week available, but the more typical CO pattern with activity diminishing after sunset.

Severe weather pattern across the central and southern plains will remain very active today into Saturday, with damaging to devastating tornadoes possible each day, especially Saturday.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

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In general, wet and stormy pattern will persists across CO through Sunday. Severe weather threat will persist across much of the southern and central plains as well as into eastern CO into Saturday. Violent tornadoes will be possible from TX north into NE through Saturday.

Another rainy and stormy day on track across CO. Atmosphere is very moist and will become unstable this afternoon, which will lead to another round of showers and thunderstorms. Some storms may become severe from the foothills east this afternoon and evening, with small to medium sized hail and strong wind gusts being the primary threat, but isolated tornadoes will be possible as well. Activity is likely to persist into the overnight hours east of I-25. Snow level expected to remain at or above 10,000 ft today. Storm motion today will be from the southwest at 10-20 mph.

Our stormy and wet pattern will continue on Friday, with renewed activity forming by late morning in the mountains and foothills and progressing onto the plains. Upper level low that is currently over central CA will move to near Las Vegas by Friday morning. Storm motion becomes south southwesterly on Friday at 15-25 mph. More severe thunderstorms will be possible across eastern CO from the foothills east on Friday as more favorable shear profile emerges, so more threat of damaging hail, strong winds and isolated tornadoes. Snow level may lower to 9000 ft by Friday evening and night, but any accumulations below 10,000 ft not expected to be significant.

On Saturday, upper low expected to be near the 4 Corners region and track into southeast CO by evening. This will produce a very soggy day across most of CO, with more steady type rain expected, although a few isolated thunderstorms will be possible across eastern CO, with some possibly becoming severe over the plains. Snow level expected to be in the 9000-10,000 ft range during the day, but colder air is expected to move south into eastern CO Saturday evening and night, snow level is expected to lower to 8000 ft by Saturday evening, and down to 5000-6000 ft overnight. Snow amounts difficult to predict, as much of the snow will melt initially. However, above 8000 ft, I would expect 2-6 inches of snow to be possible from Saturday evening into Sunday morning, mostly sticking on non-asphalt surfaces. Some slush and snow may stick to roads overnight, so some roads could become slick by Sunday morning. Models suggest precip will diminish during the day on Sunday becoming showery, but temps will remain well below seasonal norms with snow level remaining in the 7000-8000 ft range during the day.

Models continue to suggest from 1-4 inches of rain will be possible over portions of CO from today through Monday morning, with heaviest amounts along the I-25 corridor and foothills, so flooding will remain a concern through the weekend.

Models suggest a drying and warming trend next week, with the more typical isolated afternoon and evening showers and thunderstorms. heavier rain may be back in the forecast from next Friday into next weekend as another upper trough moves across CO. Upper level pattern in general has placed a long wave upper trough along the West Coast, something absent all winter and early spring. This type of pattern favors cooler and wetter than average conditions for CO. Models suggest this pattern to persist into mid to late May.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

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Our Pacific Northwest weather continues. Mostly cloudy day with showers remaining over the eastern plains in wrap around moisture from exiting upper low. New round of showers and isolated thunderstorms is forecast to develop today with best chances for precip from the foothills west today. Precip will develop over the mountains late this morning and afternoon and move east during the afternoon and evening hours. Storm motion today will be from the west to northwest at 10-20 mph. Snow level expected to remain above 10,000 ft, but small hail will be possible in thunderstorms.

For Thursday, flow aloft becomes southwesterly as upper low digs along the west coast. Showers and thunderstorms expected to develop in the afternoon and evening hours, with heaviest precip expected to be from the foothills east.

By Friday, upper low will be centered somewhere near Las Vegas, with a moist southerly flow over CO. In addition, a weak cold front is expected to move into northeast CO from the north which will help focus precip along the Front Range. Friday looks to be yet another soggy day for most of CO with isolated thunderstorms possible. Snow level could dip down to 9000 ft on Friday, so higher elevations may see snow, although accumulations below 10,000 ft probably not likely. By Saturday, upper low should be near the 4 Corners region, keeping CO under a moist southerly flow. Snow level could dip down to 7000-8000 ft Saturday morning with precip persisting overnight Friday into Saturday morning. Saturday looks to be another rainy day statewide with snow level hovering in the 8000-9000 ft range, so some accumulations will be possible above 9000 ft. Precip likely to persist again Saturday night into Sunday with snow level lowering to 5500-6500 ft Sunday morning. Accumulations above 7000 ft possible, with several inches of snow possible above 8000 ft. Showers likely to persist during the day on Sunday with snow level remaining in the 7000-8000 ft range, so temps to remain well below seasonal norms for Mothers Day. Not quite the major snow event we had last Mothers Day (20 inches on Conifer Mountain), but a cool and unsettled day that will limit outdoor celebrations.

For flood concerns, models forecast somewhere from 1 to 4 inches of precip from today through Monday morning across much of CO, with heaviest amounts along the I-25 Corridor and foothills. Thus, localized flooding may become an issue over the next 5 days, especially over the weekend. The cooler temps and snow may help reduce the initial flood threat, but melting snow early next week will keep local streams and rivers at very high levels.

For next week, temps look to return to or exceed seasonal norms and precip will be much more isolated. Looks like much more typical afternoon and evening showers and isolated thunderstorm chances Monday through Friday next week. Models suggest better precip chances next weekend as an upper trough once again skirts across CO.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

---

Made it back from Alaska yesterday, always fun to visit the northern frontier, even if it was for work.

Upper trough currently near the 4 Corners region and will move northeast across CO today. This will increase precip chances for nearly all areas of CO today. Some heavy rain will be possible across eastern CO today under southeast flow aloft. Models suggest from 0.5 to 2.0 inches of rain will be possible through Wednesday morning, so areas with high stream flows will be prone to local flooding, as NWS has issued a Flash Flood Watch for today. Heaviest rain looks to be this afternoon and evening, with precip diminishing after midnight as upper tough axis moves through. Snow level looks to remain at or above 10,000 ft through the remainder of the week, but higher mountain areas could receive significant snowfall.

For the rest of the week, precip will remain in the forecast. Afternoon and evening showers and isolated thunderstorms will persist Wednesday through Friday with action developing in the mountains and moving east during the afternoon and evening hours. Some heavy showers will be possible each day, but more localized than today.

Next significant system will move south along the West Coast this week, then bottom out over AZ and move northeast across CO this weekend. This system, similar to today, will increase precip Saturday and Sunday, with some very heavy rain again possible. Models suggest another 1-3 inches of rain will be possible across much of CO from Friday afternoon through Monday morning. Snow level appears to lower with this next system, with snow level Saturday lowering to 9000 - 10,000 ft, and could lower further on Sunday down to 7000-8000 ft, which could produce several inches of snow at higher elevations in the foothills.

For next week, models suggest a warmer and drier pattern, with just some typical afternoon and evening showers and thunderstorms, bit not the organized precip we have seen/will see this week. This unusually heavy precip for May will certainly help keep fire danger low, but too much will cause flooding issues, so stay alert for flood warnings today and over the weekend if you live in a flood prone area.

_________________
"Climatology is what you expect, Weather is what you get".

"It is better to be roughly right than precisely wrong".

Bump for 5/6 update

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Bump for 5/9 update