Aikyam-Lab/Synoptic-Bench huggingface dataset:
/DL/ Prior discussion below: In the wake of yesterday's low pressure system passing through, weak cold air advection will continue into the day today. This will help to reinforce the low stratus deck in place across the region and thus keep the diurnal temperature range "flattened" more than usual. Low-level clouds may begin to break up some by the evening as upper-level flow becomes southwesterly with a digging trough to our west, and as low-level begins to veer in advance of this system. slowly countering the cooler air in place currently.
847 AM MDT Sun Oct 25 2020 With the high pressure building in, things are relatively quiet this morning across the area, save for a few leftover upslope snow showers along and just north of the Little Belts. 520 AM MDT Sun Oct 25 2020 (25/12Z TAF Period) North to northeast flow aloft will prevail over Montana through this evening as the upper level trough continues moving southward.
After the cold start to the week, the EC and GFS continue to trend toward a more zonal configuration to the upper level flow for the later half - even ridging by the weekend (EC a bit quicker, stronger in this stead).
518 AM EDT Sun Oct 25 2020 A weak area of low pressure will track up the east coast later today and tonight. Behind this system, a weakening cold front will push in from the Great Lakes Monday, then stall out south of the state.
Under northerly boundary layer flow and socked in with clouds, most of us are going to struggle to get into the low 60s.
330 AM MDT Sun Oct 25 2020 Current surface analysis shows frontal boundary from the central Rockies to the southern Plains, with low pressure along it over western CO and cold high pressure centered over western MT. Upper level analysis shows large, positively tilted trough over the northern Rockies, with strong 100+ kt jet extending across WY, SD, and into NE. As the trough and associated upper level jet continue to track slowly south-southeast across the region today, snow will gradually shift southward as well into and through the central Plains. Highs Monday will be slightly warmer, upper teens and 20s, with lots of sunshine.
425 AM MDT Sun Oct 25 2020 Current surface analysis shows frontal boundary from the central Rockies to the southern Plains, with low pressure along it over western CO and cold high pressure centered over western MT. Upper level analysis shows large, positively tilted trough over the northern Rockies, with strong 100+ kt jet extending across WY, SD, and into NE. As the trough and associated upper level jet continue to track slowly south-southeast across the region today, snow will gradually shift southward as well into and through the central Plains. Highs Monday will be slightly warmer, upper teens and 20s, with lots of sunshine.
Based on that, went with the cooler CONSSHORT guidance for daytime highs, which is several degrees below the NBM.
615 AM CDT Sun Oct 25 2020 An upper level trough crossing the region early this morning will bring light snowfall to the CWA.
735 AM EDT Sun Oct 25 2020 A few scattered light lake effect rain showers are possible south of Lake Ontario this morning, otherwise high pressure will bring dry and cool weather for the rest of the weekend.
Low clouds, drizzle, and temperatures in the low to mid 50s are being reported areawide right now. 08Z Surface analysis places a cold front from the Carolinas back through Southern Alabama and into the Central Gulf of Mexico. Models continue to indicate the upper level flow transitioning back to the southwest later tonight into Monday with rain chances gradually increasing across Northeast Arkansas as a cold front approaches the Mid-South and then becomes quasi-stationary as it becomes nearly parallel to mid-level flow aloft.
After about a week of a rather active wintry pattern, things finally begin to trend quieter and warmer through the rest of the week.
With the high pressure building in, things are relatively quiet this morning across the area, save for a few leftover upslope snow showers along and just north of the Little Belts.
A positively tilted trough continues to dig across the Rockies and into the central plains, inducing an area of isentropic lift across the state. Snow will continue to spread into central and southern Iowa this evening and overnight as the trough continues to shift south and east. The longwave trough that brought today's snow will continue to dig into the southern plains with a well defined cut off low by the beginning of the week.
The combination of wind and broken clouds kept some spots in central Washington warmer than expected like Wenatchee at 28 and Omak at 25. With a good deal of sunshine expected this afternoon, high temps for Wenatchee, Moses Lake, and Ephrata should rebound into the low 40s. Areas that have snow on the ground will struggle to reach the low to mid 30s. /GKoch 18Z TAFs: Winds are relaxing this morning and will continue to decrease this afternoon as cold high pressure builds into the Inland Northwest. Bands of high clouds will thicken toward Monday morning and the north Idaho Panhandle and far northeast Washington may experience a few flurries on Monday, but no precipitation has been included at the TAF sites trough 18z.
217 PM CDT Sun Oct 25 2020 Positively tilted upper level trough will slowly push east of the forecast area overnight. With clearing skies and generally light westerly surface winds, expect lows to range from the low single digits below zero southwest to the 5 to 10 degrees above zero range elsewhere.
This will effectively keep all precip frozen across the CWA (snow/freezing drizzle), except for the far southeast reaches of the CWA for parts of southeastern Mitchell County in Kansas this afternoon.
Rain chances today look slim, even for the higher elevations today. AC Chattanooga Airport, TN 62 74 61 77 62 / 10 10 10 10 20 Knoxville McGhee Tyson Airport, TN 61 73 59 74 58 / 10 10 10 10 20 Oak Ridge, TN 61 72 58 74 57 / 10 10 10 10 20 Tri Cities Airport, TN 56 73 55 72 55 / 0 10 10 10 10.
For this reason, we'll be a little warmer tonight than last (blanketing affect) and I'm going to keep tomorrow's afternoon highs similar to today's.
High pressure ridging in and ceilings are expected to stick around at most TAF sites for most of the day. Southern flying areas will se a slight break with higher temperatures breaking the inversion, allowing some drier air aloft to mix down and dissipate some of the lower stratus.
We have has some patchy freezing drizzle in some locations, but for the most part, has not been all that impactful, it appears. The positive tilted upper trough is still sinking south. System midweek from closed low heading out of the southern Rockies into the southern Plains could paint some precip in our southern half of the CWA.
A deep mid/upper level low pressure system will drop south into the Four Corners region on Mon/Tue time frame, forcing the flow over our area to become more swly with time.
An upper level trough is located over the northern United States with base tilted towards the southwestern United States. An upper level ridge develops Monday over the eastern Gulf of Mexico, promoting southwesterly flow aloft over the area through the end of the period Monday evening. On Monday, expect a similar evolution to unfold with morning fog/stratus gradually eroding, giving way to partly to mostly cloudy skies and highs in the lower 80's nearer the coast with middle 70's inland.
Broad troughing is evident from the upper Midwest WSW to the Intermountain West. As the overnight hours progress, the trough will undergo a fracture as the base of the trough beings to close off near the Four Corners. This will allow the northern portion of the trough over the northern Plains and upper Midwest to progress eastwards. Looking a little closer to home, weak isentropic lift and the slightly sharper upper trough could allow for weak showers to develop especially lake effect showers approaching daybreak. Over the course of the day on Monday, the northern trough swings through to bring chances for showers across the area through the day. Monday evening a lobe of vorticity is forecast to lift across the mid-Mississippi Valley NE into the lower Ohio River Valley.
A cold upper level trough will rotate southeast across the Great Basin through Monday. Precipitation will concentrate south of the trough through tonight, with much colder temperatures and gusty northerly winds trailing the trough into early this week.
Winds will shift from the east-northeast to more of a north-northeast direction today into tonight as a low pressure system passes to our southeast. and a weak trough approaches.
Dry weather into early this week with an upper ridge offshore of the area.
Mostly cloudy skies to persist overnight as southerly flow of moisture condenses above the cooler airmass in place at the surface. Through Monday night, the highest rain chances will be across southeast Oklahoma and northeast Texas, mainly along and northwest of the frontal boundary.
332 PM EDT Sun Oct 25 2020 A weak area of low pressure will track up the east coast through tonight. Behind this system, a weakening cold front will push in from the Great Lakes Monday, then stall out south of the state.
Additionally, as the ice cloud is lost by late Monday afternoon, a transition to a wintry mix/light freezing rain/drizzle is expected into the evening hours. With temperatures just below freezing and warm ground temperatures, the highest accumulations will tend to reside on insulated/elevated surfaces such as grass and bridges.
Ceilings hover between 3000 and 5000 ft through the TAF period with the highest likelihood for any MVFR ceilings (and possible spotty light rain) between 04z and 09z. Large jet feature will progress into the area within the southwest flow regime that becomes established along the periphery of this upper troughing.
However, the clouds will hold temperatures steady in the upper 50s with a few places in the lower 60s. Deep upper level trough will dig in across the western CONUS and then slowly move east to start the work week. As a result, the flow becomes more southwesterly bringing warmer air into the area.
155 PM MDT Sun Oct 25 2020 The latest water vapor images and RAP model analysis shows a deep trough over most of the western/central CONUS with a large ridge off the West Coast. Upper low pressure was centered over the ID/UT/WY area with a strongly positive tilt.
As we head into the late afternoon/evening, snow will continue to push southeast toward the Highway 20 corridor. In regard to temperatures, upper level clouds combined with light winds and fresh snow will likely keep highs in the low to mid 20s, causing high cold temperature records to be in jeopardy.
Temps should mainly be limited to the low to mid 70s in the north and east and may even trend cooler if some areas never get much scattering of the stratus. Morning lows will settle into the low 60s. The forecast will depend heavily on the timing of a strong upper level low pressure system and the track of current T.
210 PM EDT Sun Oct 25 2020 A trough is in place across the area with a cold front to the west across the central panhandle and TS Zeta in the western Caribbean. Through Monday, the trough and front will gradually wash out over the area as easterly flow continues and drier air in place across the northern half of the area keeps isolated to scattered showers and isolated thunderstorms each afternoon.
Despite the light amounts, surface temperatures were below freezing cross the region, and this caused black ice to form on area bridges and overpasses.
Warmer air aloft will moderate some low temps in the mountains and foothills Monday night.
Higher pressure continues to ridge into the CWA increasing stability. Winds will continue to shift southeasterly through the afternoon as another cold front will approach early this week.
340 PM CDT Sun Oct 25 2020 Key message of the day: Patchy freezing drizzle will continue this afternoon before snow begins to increase in coverage, especially after dark. Changes from previous forecast: Added freezing drizzle mention and ice accumulations to areas that have yet to see any snowfall. Synopsis/Forecast: Large scale lift is expected to increase across Nebraska this evening ahead of an approaching upper trough. Before this, patchy freezing drizzle will continue and some light glaze is possible, especially on elevated surfaces. Record/near-record cold high pressure moves in behind this system with near-record lows tonight and again Monday night.
301 PM EDT Sun Oct 25 2020 A weak area of low pressure will track up the east coast through tonight. Behind this system, a weakening cold front will push in from the Great Lakes Monday, then stall out south of the state.
Heading into early Monday morning, temps will be near freezing along and northwest of the Illinois River Valley, allowing for the development of snow in the lower atmosphere. At this time, with the warm sfc layer, not expecting any freezing rain. This will be aided by upper level High pressure off the se coast of the US, lifting additional moisture to the region.
Cloud cover could be really problematic through the night, at least until the upper trough axis swings through. Trended sky cover toward a more pessimistic outcome through the evening, but some clearing ahead of the upper trough may still occur. Positively tilted upper level trough will slowly push east of the forecast area overnight. With clearing skies and generally light westerly surface winds, expect lows to range from the low single digits below zero southwest to the 5 to 10 degrees above zero range elsewhere.
It is a warmer forecast than the very cold bias corrected MAV guidance. Arctic high pressure moves overhead Monday and then slowly south through wrn KS Monday night.
500 PM MDT Sun Oct 25 2020 The latest water vapor images and RAP model analysis shows a deep trough over most of the western/central CONUS with a large ridge off the West Coast. Upper low pressure was centered over the ID/UT/WY area with a strongly positive tilt.
As the low level flow turns SW, low cigs should be able to build into the Tri-Cities area by 12Z. DGS Chattanooga Airport, TN 63 73 60 76 60 / 10 20 0 10 20 Knoxville McGhee Tyson Airport, TN 61 73 59 73 57 / 10 10 0 10 20 Oak Ridge, TN 62 72 58 72 57 / 10 20 10 20 20 Tri Cities Airport, TN 56 73 55 72 55 / 10 10 0 20 10.
Temps are still a tad bit warmer than previously forecasted, so have adjusted temps slightly to better align with latest observations.
Key message of the day: Patchy freezing drizzle will continue this afternoon before snow begins to increase in coverage, especially after dark. Changes from previous forecast: Added freezing drizzle mention and ice accumulations to areas that have yet to see any snowfall. Synopsis/Forecast: Large scale lift is expected to increase across Nebraska this evening ahead of an approaching upper trough. Before this, patchy freezing drizzle will continue and some light glaze is possible, especially on elevated surfaces. Record/near-record cold high pressure moves in behind this system with near-record lows tonight and again Monday night.
345 PM MDT Sun Oct 25 2020 A complex storm system and associated cold front continues to drop south across the forecast area. The Interstate 70 corridor has transitioned over to snow behind the cold front by late this afternoon. Expect the cold front to move through Montrose and Gunnison by the early evening, and through the southern valley locations around midnight. The elongated trough and associated closed-low will drop south near the Four Corners region by Monday morning. Expect snowfall to diminish from the northwest on Monday as the closed low drops south into Arizona with the best focus for snow across the southern half of the forecast area.
On Monday, the flow aloft decreases with the upper trough axis pushing slowly southeasterly. The low level wind and pressure fields keep north and northeasterly upslope surface winds going this evening and more easterly overnight into Monday morning. Will keep the high pops going overnight, then I will start to decrease them from north to south through the day Monday.
A cold front continues its southward movement through Nevada this afternoon.
540 PM MDT Sun Oct 25 2020 A complex storm system and associated cold front continues to drop south across the forecast area. The Interstate 70 corridor has transitioned over to snow behind the cold front by late this afternoon. Expect the cold front to move through Montrose and Gunnison by the early evening, and through the southern valley locations around midnight. The elongated trough and associated closed-low will drop south near the Four Corners region by Monday morning. Expect snowfall to diminish from the northwest on Monday as the closed low drops south into Arizona with the best focus for snow across the southern half of the forecast area.
Temperatures will be a little warmer Monday afternoon, but still 10-20 degrees below normal.
937 PM EDT Sun Oct 25 2020 High pressure will wedge across the Mid Atlantic states through tonight into early Monday.
/issued 210 PM EDT Sun Oct 25 2020/ A trough is in place across the area with a cold front to the west across the central panhandle and TS Zeta in the western Caribbean. Through Monday, the trough and front will gradually wash out over the area as easterly flow continues and drier air in place across the northern half of the area keeps isolated to scattered showers and isolated thunderstorms each afternoon.
A cold front continues its southward movement through Nevada.
Clear skies means that this second night of freezing is much more certain for widespread areas within the warnings. The one place were some small amount of uncertainty exists is in the Shasta Valley, where stronger surface winds overnight could make it a bit tougher to reach freezing. As a ridge builds into the region Monday introducing high pressure, the strong east winds will begin to subside. winds aloft will be conducive for downsloping in Brookings, where maximum temperatures could creep into the low 70s. Moderate thermal trough winds will keep winds over the coast range elevated through monday night, the impacts of which are discussed in the fire weather section below. Monday night will be the third consecutive night where freezing temperatures will be possible in west side valleys, while the coast warms back up above frost producing temperatures.
If temps fall near or below freezing, this may result in a light glaze on elevated surfaces. Latest model trends are a bit faster with the colder, freezing temps, and given our western areas have not warmed and are hovering near freezing already, the wintry precip transition to all snow should be brief overnight. Temperature profiles vary by a few degrees towards east central KS which may result in freezing rain or sleet mixing in with the snow.
Expect very windy conditions through sunset as a cold front approaches the region.
A ridge of high pressure just offshore will keep weather systems to the north of the area.
Locally, high pressure currently extends along the Canadian border with a lobe from northern Montana into northern Louisiana.
1035 PM EDT Sun Oct 25 2020 Trough axis extends NE-SW from near Buoy 41009 to Punta Gorda (KPGD). Scattered showers SE of the trough axis will persist across our southern counties until instability is exhausted then gradually diminishing overnight. Lows will fall into the low 70s tonight.
Surface temperatures may cool enough at KBVO to support light freezing rain at times this afternoon. The freezing line was located back to the west from near Amarillo through Northwest Oklahoma to just northwest of Wichita. Temp profiles northwest of I-44 would suggest that below freezing surface temps could be possible along and northwest of a line from near Oilton to Bartlesville. With surface temps possibly at/below freezing combined with a mid level warm nose. wintry weather in the form of freezing rain will be possible along and northwest of this line. There is a hint that far northwest Osage county could maybe see some patchy sleet as temps just above the surface near -3C could possibly allow for some refreezing of the precip.
A small chance of freezing drizzle remains possible across southeast portions of the CWA.
Currently, a broad and elongated positively tilted trough extends from the Desert Southwest into the northern Plains and upper MS Valley. Cold Canadian high pressure continues to be responsible for persistent low level CAA into the area. As the upper low lifts out of the Desert Southwest, another period of a wintry mix looks possible from south to north across the area.
We will remain in a rather moist regime with southwest flow aloft for the short term period, as we remain under the influence of the upper ridge with its axis to our east.
Cold front is oozing eastward down the 160 corridor and likely to reach Durango in the next hour or so. A complex storm system and associated cold front continues to drop south across the forecast area. The Interstate 70 corridor has transitioned over to snow behind the cold front by late this afternoon. Expect the cold front to move through Montrose and Gunnison by the early evening, and through the southern valley locations around midnight. The elongated trough and associated closed-low will drop south near the Four Corners region by Monday morning. Expect snowfall to diminish from the northwest on Monday as the closed low drops south into Arizona with the best focus for snow across the southern half of the forecast area.
The freezing line was located back to the west from near Amarillo through Northwest Oklahoma to just northwest of Wichita. Temp profiles northwest of I-44 would suggest that below freezing surface temps could be possible along and northwest of a line from near Oilton to Bartlesville. With surface temps possibly at/below freezing combined with a mid level warm nose. wintry weather in the form of freezing rain will be possible along and northwest of this line. There is a hint that far northwest Osage county could maybe see some patchy sleet as temps just above the surface near -3C could possibly allow for some refreezing of the precip.
Several weak waves of low pressure will move along the front, producing occasional showers.
That said, the EC trended warmer about 4 runs previous, and has stayed a bit more optimistic. After the cold start to the week, trends in the models continue to favor moving to a more zonal upper level pattern, with long wave ridging even building in for the end of the weekend. The EC has been trending this way for the past couple days, and the GFS may be catching on to more aggressive warming/ridge building too.
307 AM CDT Mon Oct 26 2020 Latest water vapor loop has a digging mid level trough over the southwest US. Ample moisture being pushed out ahead of the trough over the central and eastern US. At the surface a cold front was over the deep south. This is where the highest PoPs and QPF will be through Tuesday afternoon.
There is another strong closed low system that moves out of the southwestern CONUS mid week.
Otherwise, warmer highs compared to today are expected Monday from a few degrees in the Basin to exceeding 10-15 degrees and more in central OR. High pressure continues to influence the area tomorrow with light winds prevailing (less than 10 kts).
Also, some locastion along the highline are just barely making wind chills criteria.
The upper trough that has brought bitter cold to the forecast area over the weekend will move to the east this morning. The coldest air will also be moving to the east today which will allow for somewhat warmer temperatures. After the wave moves to the east tonight, flow aloft becomes a much warmer WNW flow aloft with chinook warming developing off the Rockies. This will bring warmer temperatures into the forecast area on Tuesday.
After a chilly morning, high pressure building in over the Pacific Northwest will bring dry weather through midweek with temperatures slowly warming back to normal.
An upper level trough digs into the Desert Southwest on Monday, which causes the ridge draped across the Gulf to become anchored over the Southeast and western Atlantic. Ridging aloft and drier air over the region in the wake of the recent front will suppress any convection on Monday.