Fall knocks on the door this weekend
Monday, August 15, 2016
A couple of week circulation centers currently located in Nevada and just off the northern California coast will keep the threat of afternoon showers for the Steamboat Springs area through midweek as they meander around the Great Basin. The chance for afternoon showers will increase for Tuesday and more so for Wednesday as the airmass gradually moistens. Due to the still dry lower atmosphere though, we may see more wind than rain.
Some cool air from the North Pole will break away from the Polar Vortex and travel southwards across western Canada, bringing an unseasonably cool airmass southward in several pieces. The first minor front is timed for Thursday afternoon or evening and may phase with some of the Great Basin energy and allow for a good chance of wetting rains through Thursday afternoon and evening.
The strongest push of cool air looks to occur around Friday afternoon or evening as a well-defined wave travels from the north-northwest over northern Colorado. As with the Thursday wave, more Great Basin energy will be pulled over our area contributing to more wetting rains with possibly strong storms Friday, especially in the afternoon and evening.
Saturday should be noticeably cooler with possible light showers in the cool and unstable northwest flow. A trailing wave will reinforce the cool air with the third and final front timed for Saturday evening, and again this may increase the chances for showers that may last into the overnight hours.
The flow backs to the west by early Sunday bringing in dry air and allowing temperatures to warm and the skies to clear. This trend looks to continue into the beginning of the next work week.
Beautiful weekend followed by gradually increasing moisture next week
Friday, August 12, 2016
Cooler and very dry air has invaded the Steamboat Springs area after the cool front passed through last night leading to a beautiful weekend forecast with cool nights and seasonably warm days. A trailing wave in the current northwest flow may produce some clouds Saturday afternoon and perhaps even a stray high-mountain shower, but Sunday looks to be mostly cloud-free with warming temperatures as the western ridge rebuilds behind the departing front.
A trough of low pressure crossing the West Coast on Sunday will split, with pieces of the southern portion traveling across the Great Basin on Monday and Tuesday. Some upward motion and limited moisture will allow for the chance of afternoon showers over our area those days under warmer temperatures.
Another splitting Pacific storm approaches the coast around Wednesday with the southern portion forecast to take up residence off the central California coast for the rest of the work week. The southwesterly flow ahead of the lingering trough will once again allow deeper southern moisture to travel over the region, increasing the chance of wetting rains for Wednesday and Thursday.
The northern portion of the split will be slowed as additional Pacific energy reinforces the cool air in the storm and looks to eventually bring another cool front through the area late in the work week or early the following weekend.
Drying trend interrupted midweek and still followed by cool front
Monday, August 8, 2016
A storm currently located in in Washington state will first move east through the Idaho panhandle tomorrow and then northeast to the north of Montana by Wednesday. Energy ejecting from this storm earlier today gave us a couple of rounds of much needed early-morning thunderstorms today.
Additional Pacific energy will travel southwards along the West Coast and keep a trough of low pressure extending from the eventual north-of-Montana low back towards northern California. Ahead of this trough, the drying southwest flow evident this afternoon will continue Tuesday, though there is still a threat of late afternoon storms as lingering moisture is heated by the sun.
The dry Wednesday promised in last Friday’s forecast is in jeopardy as moisture from Tropical Storm Javier, currently located near southern Baja, is drawn northeastward ahead of the California trough. It again looks like the best moisture will remain south of northern Colorado, but there may be enough in proximity to Steamboat Springs to allow for a round of afternoon and evening storms in more humid conditions.
This moisture plume will be quickly shunted to our east as the California trough moves inland and then across the Great Basin on Thursday. Pieces of energy ejecting from this Great Basin trough will likely induce more afternoon storms for Thursday before a cool front moves through the area late Thursday night or early Friday morning.
There is some Pacific moisture within this trough, the first of this late-summer season, and there may be enough upward motion to induce some Friday storms in the relatively cool and unstable northwest flow behind the front.
Though there is mid and upper-level drying behind this trough, trailing energy in northwest flow looks to move over the area on Saturday and may spark another round of weaker afternoon storms. Temperatures should return to normal to above normal by Sunday and heading into the next work week as a flat western ridge builds behind the departing system.
Wet start to weekend followed by modest drying
Friday, August 5, 2016
A Pacific Northwest storm and associated trough of low pressure extending southward along the West Coast continues to draw monsoonal moisture over Colorado and southern Utah in the southwest flow ahead of the storm. While Steamboat Springs is on the northern edge of the moisture plume and heavier rain, ill-defined waves of energy either ejecting from the West Coast storm or embedded in the southwest flow will keep good chances of wetting rains around through Saturday.
A wave of energy traveling along the southern end of the West Coast trough will nudge the entire storm eastward around Saturday night, shifting the highest moisture to the east as well. Though a significant drying trend starts then, a weak ejecting wave looks to travel close enough to our area on Sunday to continue the threat of afternoon storms, possibly strong, that may continue into the evening.
Additional Pacific energy keeps parts of the storm to our west, with continued southwest flow keeping the driest air to our west through at least Tuesday. The remaining moisture will keep the threat of afternoon storms around for Monday and Tuesday under noticeably drier conditions.
Much drier air looks to finally intrude by Wednesday as what remains of the West Coast trough moves bodily inland. Though the storm will stay mostly to our north, it will be close enough to create dry and breezy weather for Wednesday and part of Thursday. The southern part of the storm is forecast to drag a cool front over our area by later Thursday or early Friday, and may be the focus for thunderstorms for the end of the work week, especially Friday.
Wetting rains more likely for the end of the work week
Monday, August 1, 2016
A Pacific Northwest storm will cross the coast Tuesday morning and travel well north of the Steamboat Springs area along the US-Canadian border on Wednesday. Drier air ahead of this storm has spread through northern Colorado in westerly flow and will reduce, but not eliminate the threat of afternoon storms for Tuesday.
As the northern storm swings north of our area on Wednesday, winds will increase ahead of a weak cool front forecast to move through northern Colorado late Wednesday or early Thursday. The storm will be drier than I thought in the last forecast, so the meteorological concern will be wind rather than rain for Wednesday and Wednesday night.
Though Thursday will start cool and dry, a relatively well-defined wave from the southwest will travel across the Four Corners later Thursday and western Colorado by Thursday night into Friday. Moisture will rapidly increase ahead of this wave, increasing the chance of locally heavy rainfall by Thursday afternoon and possibly extending into the night.
By Friday, another Pacific Northwest storm carves out a trough of low pressure off the West Coast, keeping the moist southwest monsoonal flow going for the weekend. A currently ill-defined wave may move over our area on Friday, again increasing the threat of locally heavy rainfall that may last into the evening.
Earlier forecasts had dry air overspreading our area for most of the weekend, but current forecasts have the West Coast trough deeper and more persistent, keeping the still moist, but drying, monsoonal moisture plume over our area through Monday. This will continue the threat of afternoon storms through Monday before the Pacific Northwest storm moves inland, bringing dry air and likely eliminating the chance of afternoon storms for the rest of the next work week.