Friday, November 30, 2007

Weekend Update


Focus Region: NE Colorado and SW Nebraska
Short Range-
Models showing moisture filling in on western slope Friday night with southerly winds. Areas of Denver may see a trace of snow with this moisture fetch over the mountains. Models suggesting moisture will be advected North over KA and NE as well as NE CO by Saturday morning by a SE wind. The snow line looks to setup across the I-76 corridor around Ft. Morgan and get heavier the further to the East. Water equivalent around 0.01-0.10 inches which would equate to around 1 inch of snow in the Saturday morning hours. By 11 am all precipitation has moved E ahead of the Low pressure. Area of focus region temperatures around lower to mid 30's F. Any precipitation during the noon time looks to be in various forms, sleet, cold rain, wet snow, as the freezing line sits on Imperial, NE. 5pm Saturday light precipitation over the region with a SW wind changing to the North as a frontal boundary passes through bringing temperatures around the 30's. Saturday night a north wind dominates after frontal passage (FROPA) with temperatures around 30 F. Some radiational cooling from the surface from day time precipitation may occur which would drop the temperatures between 20's and 30's for Saturday night. Sunday morning a possible shower or two but otherwise looking to clear out as all precipitation has moved to the east. Sunday temperatures warming near 40's with strong NW wind around 15 mph. Travel home looks nice and clear but cool temperatures.

Thursday, November 29, 2007

Changes for the Weekend


Short Range-
Current storm from the Southwest still on track for the weekend. Moisture will be in place over western slope of CO Friday night. Surface Low pressure position now expected to be over Central CO and will bring moisture from south to north across eastern CO and southwest NE and also along I-76 corridor for Saturday morning. Saturday noon the Low will deepen over the Rockies continuing to push moisture eastward. Saturday night the Low will move northeastward taking most of the moisture with it. Sunday morning low level moisture still hanging around leaving a possible shower or two. Sunday mid-day partial clearing skies with colder temperatures.

Saturday morning precipitation will be in the form of rain/snow/mix, take your pick, and will turn towards snow Saturday night as the cold air moves over the area. Temperatures Saturday morning will be slightly above freezing and will warm towards the noon time then drop off for nightfall due to partial clearing. Saturday max temperatures will be around upper 30's giving a cool rain process. Precipitation form may switch between rain, sleet, freezing rain, and snow throughout the day as the temperatures fluctuate. Precipitation totals for the I-76 corridor are expected to be around 0.20 inches, which may equate to around 2 inches of snow. Sunday temperatures will warm slightly to around 32 F by noon but will remain cold with clearing skies. I will update this again tonight or tomorrow morning with more details.

Tuesday, November 27, 2007

Unsettled Pattern

Short Range-
Several waves are setup to come through the area during this unsettled period. The first wave or disturbance will pass with a cold front from the north on Tuesday night 11-27. Behind it NW flow will provide a drying atmosphere giving way to little moisture on the Eastern slope. Cold air with this front will remain for most of the week as we have a very weak ridge setting up behind the frontal passage.

Long Range-
The big storm setup for Colorado that I have been watching for over a week is beginning to decay in the models. On Friday the shallow ridge of high pressure weakens and moves eastward as the next system forms up over the Eastern Great Basin and Four Corners area drawing rich moisture fields from the Pacific/Baja California region. An upper level cutoff Low gets entrained into the flow and the Low pressure over four corners will intensify. By Saturday morning large moisture fields are in place over Western Slope of CO. Saturday afternoon as the Low pressure moves eastward over Southern CO, an upslope component will develop bringing light showers of rain/snow mix across eastern CO and SW Nebraska through late Saturday night. Light snow accumulation around 2-3 inches could be expected with this shower activity throughout the day. By Sunday morning the Low pressure system will eject eastward over the Midwest leaving showers possible across CO and NE. Sunday midday looks to be clearing out with high pressure beginning to build over the area. Temperatures for the weekend across eastern CO and southwest NE will struggle to get above freezing with the exception of daytime heating.

Monday, November 19, 2007

More Changes Coming...

Short Range-
Major changes this week with two snow storms on track to bring only light accumulations to the Front Range. A cold front associated with the first storm is expected to pass through Tuesday morning slowly dropping the temperatures from abnormal highs. Light snow is expected to follow and develop from N to S across the Front Range on Wednesday early morning and decrease intensity late Wednesday evening with possible lingering showers on Thursday morning. Upper level dynamics looking fairly weak for any extra enhancement on the snow accumulations. Accumulations projected at 2-3 inches and will stick around for awhile due to very cold air mass following this cold front. A short break in the weather chain on Thursday before another round of snow associated with storm #2. A leak L pressure will develop over four corners area on Fri morning with possible light snow showers moving from S to N from the mostly Southerly flow around the Low. As the Low moves over Southern CO a slight shift in surface flow from S to SE will continue the snow showers into Friday night. Accumulations around 2-3 inches with this storm. Increasing High pressure from the NW will eject this system out giving slightly warmer temperatures through Wednesday 11/28.

Long Range-
A big system is brewing in the Pacific and will need to watch the timing as it approaches. Long range models are suggesting a lee side Low pressure to form over Central CO on Thursday 11/29 that looks to stall and intensify and move S over Northern NM and very slowly move East on 11/30. The position of the Low will provide an excellent upslope flow over the Eastern Slope bringing light snow Thursday night. As the Low intensifies and pushes slightly south moderate rates of snow could be expected across Eastern CO and SW NE on Friday. Friday night and into Saturday morning the Low continues to intensify and begins to eject out eastward which will act to increase pressure gradients, increasing the N to NW winds slightly, and continue the moderate rates of precip. Low continues to move eastward over Great Lakes region tapering off the snow over the Colorado/Nebraska area by Sunday. At this point models are showing around 1.0 inches of water content, which could translate into 10 inches of snow depending on quality of dendritic patterns (snow/ice crystal pattern). This is a storm to watch future develops as the days continue. Much could change by 1 DEC. Stay tuned...

Friday, November 16, 2007

Possible Snow Coming for Turkey-Day

Short Range-
Should be a nice finish to our week with moderate temperatures under NW flow. Some moisture moves in at the mid levels giving a chance for some cloud development Saturday afternoon. We will be dominated by NW flow for the remaining part of the weekend acting to warm and dry the low level atmosphere. Monday returns with changing W to SW flow in advance of a major trough of Low pressure to move through on Tuesday.

Long Range-
Long range models are suggesting a major storm system to move through Tuesday bringing snow and some cold air to last through the week. A low pressure is expected to setup in W Kansas and move slightly south while losing strength. Frontal passage (FROPA) appears to be Tuesday morning with snow expected through the day on Tuesday and into Wednesday morning before the system ejects Eastward on Wednesday leaving very cold air in place under a high pressure. The position of the surface Low is favorable for upslope flow giving enhanced snow accumulations. Accumulations right now appear to be 3-4 inches but depend on the dynamics of the system. Jet stream is placing a decaying 100knot jet streak over southern CO which will enhance system dynamics and help drive the upslope flow even more. We'll keep watching the models to see more details as the system approaches. Stay tuned...

Monday, November 12, 2007

Nothing Special This Week

Short Range-
Well a great Pacific system sure gave way to high pressure and clearing clouds. A little short on precip for sure and clearing clouds by afternoon. Expect more of the same mild and unseasonable weather for Tuesday. A weak disturbance to our North will bring increasing clouds on Wednesday with no signs of any major precip for the Front Range. A fairly strong high pressure will return once again on Thursday with clearing skies and NW flow warming us through the end of the week.

Long Range-
Long range is looking pretty quiet with nothing too significant to speak of in terms of major storms. Another small disturbance will move to our north on Saturday giving increasing cloudiness Saturday. The next possible system looks to be around Thanksgiving holiday but right now not looking too impressive. Things could change and the jet stream could shift further south and bring something significant our way in terms of moisture. Stay tuned....

Thursday, November 8, 2007

A Slight Change


Short Range-
There is slight change in the forecast for the weekend. The remaining part of this week will be very nice and unseasonably warm under the High pressure dominating the West. Saturday a slight cool down is expected as we return to W to SW flow ahead of the advancing system. Winds should remain fairly calm but all in all a nice finish to our week.

Long Range-
Looking further into our weekend forecast, we should expect changing weather for Sunday as a strong Pacific system makes its way into Colorado. Unfortunately models are suggesting most of the moisture to stay in the mountains and be cloudy down in the Denver Front Range. This should be a great snow maker for the mountains on Sunday and Monday. Clouds are expected to increase on Sunday afternoon and remain over night into Monday mid-day. We could get a shot of rain/snow mix during this time but it is not looking favorable for heavy moisture as the Low pressure is setting up too far East. Skies should mostly clear out by Monday evening with possible lingering mid level cloud decks.


Tuesday, November 6, 2007

Quiet week ahead

Short Range-
Nothing much to speak of as far as weather concerns for the short range. Nice High pressure dominating our area will bring gradual warming through the week.

Long Range-
The next pacific storm system comes onshore in the NW US on Saturday. The dominant high pressure will be replaced by a lee side Low that sets up on Sunday morning over Eastern CO and will bring moisture along with a cold front for Sunday evening. Chances of snow look pretty good for Sunday evening and overnight and into early Monday morning, providing this system doesn't get pushed to our north like other systems have the past few weeks. This system looks to be a quick mover and clear skies return on Monday afternoon. We'll watch the development of this system through this week.