Aikyam-Lab/Synoptic-Bench huggingface dataset:
A dry cold front will move through today into Tuesday, bringing strong northerly winds and much colder temperatures. Warmer temperatures and lighter winds are then expected through the rest of the week. Expect the strongest winds, with gusts of 40-50 mph, to be immediately along and just south/southwest of the higher terrain of the Mogollon Rim, Bradshaw Mountains, and San Francisco Peaks. Wind Chill values will be in the -5 to -15 range across the higher terrain. The ridge across the Pacific tries to reestablish itself but gets squeezed between the strong trough across the US and a nearly stationary low that is off to the west.
- Warmer conditions return for late week into the weekend. The combination of an upper level disturbance moving by and temperatures several degrees below freezing and an increase is moisture will result in a period of snow and a little sleet mainly late this evening and after midnight across these areas. The main impacts will be slick roads, especially bridges and overpasses by late tonight and Tuesday morning and motorists should be prepared to slow down.
632 AM EST Mon Jan 20 2025 Broad upper level trough will remain across the central and eastern U.
The combination of an upper level disturbance moving by and temperatures several degrees below freezing and an increase is moisture will result in a period of snow and a little sleet mainly late this evening and after midnight across these areas. The main impacts will be slick roads, especially bridges and overpasses by late tonight and Tuesday morning and motorists should be prepared to slow down.
549 AM EST Mon Jan 20 2025 Low pressure tracks into the Canadian Maritimes today, allowing high pressure to build in from the west through the middle of the week.
The local area remains on the western periphery of a robust long wave trough encompassing much of the eastern/central CONUS.
334 AM CST Mon Jan 20 2025 Cold air is locked in over the area with broad longwave troughing over the CONUS. Snow along the I-20 corridor is likely to come from the onset, predawn Tuesday morning as a subtle elevated cold front and northern stream short wave push in from the north.
502 AM CST Mon Jan 20 2025 - Light snow today with the highest probabilities across south central Kansas. A longwave trough continues to impact the CONUS with very cold air lingering across the Central Plains. Arctic high pressure will build southward tonight in the wake of the light snow event. A clipper system is progged to dig across the Northern Plains on Wed driving a cold front south over the area late in the period. This front will keep some cooler air in place across the area on Thu with highs mostly in the 30s.
The Arctic air has not yet reached the lower elevations in north-central Idaho, where current temperatures range from the mid-teens to low 20s. Locations in and around Elk City, Dixie, and Pierce are experiencing temperatures in the low single digits.
527 AM CST Mon Jan 20 2025 Cold air is locked in over the area with broad longwave troughing over the CONUS. Snow along the I-20 corridor is likely to come from the onset, predawn Tuesday morning as a subtle elevated cold front and northern stream short wave push in from the north.
KBYX/KAMX VWP data indicate that the shallow cold front has pushed through, but northerly flow extends up only a couple thousand feet, with moist SW flow overrunning above the shallow cool layer. Behind the front, a massive Arctic high pressure area sprawls from the Appalachians westward to the Rockies. Aloft, a huge trough covers the entire CONUS, anchored by a deep vortex near James and Hudson Bays. Today will see mostly cloudy, breezy and modestly cooler conditions, as moisture associated with the nearby front continues to linger across our area. The highly amplified pattern aloft, with a deep trough over the central and eastern CONUS, will persist through the upcoming work week.
Wind chills will not recover above -40 today, so today is the highest impacts of this extreme cold event.
However, a warm frontal boundary will allow conditions to improve through the night in western ND, and to a lesser extent, in central ND.
Discussion: In the upper levels, a deep trough is over the Central and Eastern U. At the surface, high pressure centered over the Great Plains extends over the Eastern U.
Very cold morning temps will recover into the teens and 20s (except 30s in the lowest valleys) this afternoon. The ridge of high pressure will continue to build along the West Coast, but higher diurnally driven winds will prevent extensive stagnant conditions through Tuesday.
Several bouts of surface cyclogenesis will occur, pushing two cold fronts through the Keys (in addition to the front that pushed through yesterday and remains draped just to our south).
Current thinking is that temperatures should climb just above freezing in the next 1-2 hours for many, and possibly another 2-3 hours before the northern zones accomplish this, if at all.
- Warmer temperatures through the end of the week. (Rest of today and tonight) The cold front is moving through northern Oklahoma with the band of moderate snow near the front.
Afternoon highs are forecast to remain approximately 10 to 20 degrees below normal, with temperatures only reaching the 50s across Brevard to Osceola and counties northward and reaching the low 60s across the Treasure Coast. The old front to the south will return northward across south FL by Tue as weak waves of low pressure ride along the boundary. Another wave of low pressure is forecast to ride along the old front Thu-Thu night followed by a surge of N/NW winds bringing cold and dry air into the area. (18Z TAFs) Mostly VFR conditions at all terminals, with brief MVFR cig/vis south of KVRB this afternoon due to lingering showers from yesterday's cold frontal passage.
- Light snow today with the highest probabilities across south central Kansas. A longwave trough continues to impact the CONUS with very cold air lingering across the Central Plains. Arctic high pressure will build southward tonight in the wake of the light snow event. A clipper system is progged to dig across the Northern Plains on Wed driving a cold front south over the area late in the period. This front will keep some cooler air in place across the area on Thu with highs mostly in the 30s.
Gusty winds are ongoing across NOrthern California, mainly 20-35 MPH, up to 45 MPH over the higher terrain of the foothills and Sierra. After Tuesday, ridging remains the dominant weather feature with troughing much further east, reducing the gradient and relaxing our winds over the next several days. Valley lows are expected to be in the 30s through midweek with several sites at or near freezing, from roughly south of Yuba City or I-80 broadly. NBM chances show a 30-50% chance of temperatures below freezing tomorrow morning across parts of the Central Valley , highest along the eastern portions of the Valley and from the Delta to the Greater Sacramento Area. Valley highs will be in the upper 50s to low 60s each day with cooler temps as you increase in elevation.
1156 AM EST Mon Jan 20 2025 Deepening low pressure lifts north across the Canadian Maritimes today, allowing high pressure to build in from the west through the middle of the week.
Temperatures remain in the lower to mid 60s across the Island Chain. From synopsis, fresh to strong north to northeast breezes will prevail across the Keys coastal waters this afternoon into tonight in the wake of a cold frontal passage.
1251 PM EST Mon Jan 20 2025 Deepening low pressure lifts north across the Canadian Maritimes, allowing high pressure to build from the west through mid week.
Mid afternoon surface analysis had a >10136mb high centered over western Tennessee, a >1042mb high centered over the central Plains and an inverted trough along the southeast Texas coast. The northern stream trough will swing across our region Tuesday and Tuesday night helping the >1042mb high spread southeast over our CWA. The area south of Interstate 20 has been placed in a Winter Weather Advisory and the area along the Highway 84 corridor has been placed in a Winter Storm Warning.
- While "warmer" temps are anticipated after Tue, most locations will continue to see below normal readings for this time of year. Anomalously deep upper low remains over northwest Ontario and encompasses most of the Plains through the eastern half of the CONUS, providing widespread below normal temps. Ran with a short fused winter weather advisory mainly due to the low visibility with the heavier snow band. This feature will reinforce the upper trough and will allow below normal temps to remain in place on Wed. Not much is expected to change for Thu with upper troughing remaining from the Great Lakes through the Southern Plains and will once again allow for below normal temps on Thu, with highs in the 30s for most locations.
1153 AM CST Mon Jan 20 2025 Cold air is locked in over the area with broad longwave troughing over the CONUS. Snow along the I-20 corridor is likely to come from the onset, predawn Tuesday morning as a subtle elevated cold front and northern stream short wave push in from the north.
Some locations in the higher terrain areas of northeast AL could approach Cold Weather Advisory criteria of 5 degree wind chills, but confidence in this was not high enough to warrant an advisory at this time. Regardless, overnight lows will fall to the low to mid teens with single digit wind chills and will pose a significant threat to those outside without proper insulated clothing and shelter.
- A warming trend will kick off midweek with temps near or above freezing expected through the weekend.
Expect some increasing high clouds this afternoon as an upper trough, and associated reinforcing cold front, make their approach.
Warmer temperatures will arrive allowing for at least some relief from the dangerous wind chills. Areas in the colder sector can expect blowing snow impacts to linger much longer but still have impacts be fairly isolated without falling snow while the warmer side MAY see drifting at best.
- Warmer conditions return for late week into the weekend. (This evening through Tuesday) The cold airmass is persistent this afternoon across west central Texas, as shown by temperatures in the low to mid 30s, while a broad upper-level trough persists across most of the country. Forecast soundings continue to show a notable inversion and the entire saturated column below freezing in the low levels.
A dry cold front will move through today into Tuesday, bringing strong northerly winds and much colder temperatures. Warmer temperatures and lighter winds are then expected through the rest of the week.
713 PM EST Mon Jan 20 2025 A longwave trough axis is influencing weather across the entire E CONUS. The associated cold front is over the Florida Straights and northern Cuba, with a breezy northerly flow continuing to advect in a cooler and drier airmass across the Florida peninsula. Simultaneously, a new area of low pressure is beginning to develop in the Western Gulf of Mexico. Quickly beginning to organize this afternoon and evening, this will force the cold front to begin lifting back north as a warm front tonight, creating a setup favorable for warm, moist air to advect in above a cooler low-level airmass. As the low approaches the FL West Coast tomorrow evening, rain chances increase areawide. Overall accumulations look to be on the lower side, however, as the atmosphere will not be particularly conducive or saturated for heavy rain.
As the lee trough develops towards sunrise, the temps may climb a bit, but the southwesterly surface winds will also increase, and this will drag down the wind chill values to dangerous levels, with readings in the negative 20s widespread across the plains during the early AM hours tonight.
By later tonight, we'll likely see more valley stratus and freezing fog in the valleys. The MET and MAV guidance is predicting fog, and low temperatures will be well below freezing in many of the valleys tonight. The high clouds could throw a wrench in things, although we're thinking that the dry layer and inversion strength should usher in plenty of fog. No big pattern changes as high pressure remains in control, although the different wind direction could push some lower stratus into the coast Tuesday afternoon and evening.
A Cold Weather Advisory is in effect for portions of the Adirondacks and the Northeast Kingdom tonight, with wind chills as low as 25 below zero, with wind chills on the higher summits even colder with wind chills between 30 and 40 below zero.
High pressure will dominate the weather into the middle of this week, bringing dry conditions and cold overnight temperatures. Lows will fall below freezing over much of Western Washington at least into mid-week while daytime highs will remain below normal.
754 PM CST Mon Jan 20 2025 A broad, positively-tilted, upper-level trough is currently affecting the bulk of the CONUS this evening. The low- level water vapor channel (7.
A large positively tilted synoptic trough extending from the western Great Lakes into New Mexico will reach the Ohio valley into the southern Mississippi valley by Tuesday afternoon. The minor reprieve is short lived as a reinforcing cold front is shown by all of the models Tuesday night â plunging western and central Kansas back into 850 mb temperatures ranging from â 5 C to as cold as -10C near Hays and Great Bend. The overall synoptic pattern for the 3 major global spectral models continue t show a pattern of redeveloping west coast positively tiled troughs , spreading east across the CONUS promoting additional rounds of continental cold air to plunger into the high plains.
High pressure will remain stationed off the west coast of the United States through the short term.
135 AM EST Tue Jan 21 2025 (Today through Wednesday) The latest synoptic pattern features a positively tilted long- wave trough stretching into SW CONUS, with an active polar-front jet stream encompassing much of eastern CONUS. Gradual synoptic-scale forcing for ascent in the form of low-level convergence will allow for abundant cloud coverage and isolated (light) rain showers through much of the day today, keeping high temperatures on the cooler side today, and generally struggling to exceed the lower 70s today. By Wednesday, an upper level disturbance and attendant cold front will traverse the region, yielding brisk northerly winds, though quickly shifting out of the northeast towards the latter part of the day.
The coldest apparent temperatures (as cold as around -20) will be late Tuesday night and early Wednesday over the higher terrain of the Alleghenies/Laurels. The passage of a mid-level trough could bring some light snow showers/flurries over the Alleghenies/Laurels Tuesday afternoon into the early evening, but accumulations will be minimal, if any.
At 19Z, a strong 1045+mb high pressure area was sliding southward through the Northern High Plains. Tonight, as that low pressure area moves across eastern KS and western MO, low temperatures will drop below zero for most, if not all, of the forecast area. With the center of the high moving across east central KS and western MO, areas to the north will continue to see some winds with the coldest temperatures. With that high pressure area quickly moving to our southeast, we'll see winds increase out of the south late Tuesday into Wednesday. But by Wednesday, temperatures climb into the low to mid 30s across the area. Wednesday into Wednesday night, broad but robust upper-level troughing within northwesterly flow will overspread the region.
312 AM EST Tue Jan 21 2025 High pressure will gradually build in from the west through midweek.
Little change in the dry stable weather pattern with an upper ridge off the west coast and a north-northwest flow aloft across our region.
By this evening a weak cold front with limited moisture is expected to move across the state. Calm and dry conditions will return by Tuesday morning and last through the rest of the period as high pressure takes control of the weather pattern.
- Warmer temperatures through the end of the week.
Throughout today the longwave trough that is across much of the central and eastern portions of the country will slowly move eastward as a trough moves through the western CONUS. It will still stay fairly cold in the east as the coldest air takes the longest to leave so highs will be in the lower 30s and temperatures will near 40 in the far west where the mildest air will be for the longest period of time. Overall the weather pattern should stay in a dry regime with ensembles showing the upper level winds staying mainly in a trough pattern in the eastern CONUS and a ridge in the west. A series of troughs will move through the central plains with little moisture and will mainly just bring in dry passages of cold fronts and increased post frontal winds.
- Temperatures finally return to above freezing today with milder weather for the rest of the week. As the arctic high departs to our south later this morning, light northerly winds will turn southwesterly and become breezy through the afternoon courtesy of a lee trough sharpening to our west.
However, a warm frontal boundary will allow conditions to improve through the morning hours in western ND, and central ND through the day.
The system the brought us the secondary shot of arctic air is moving into the Southern Plains leaving us under a subtle ridge. Tried to adjust lows to account for this clearing, so went with the lower end of guidance. Snow will favor the northern facing slopes with the highest totals in the Park Range and Flat Tops.
(Today through Wednesday Night) A new cold front is pushing SE through the state early this Tue morning.
Winds remain light though have mostly shifted to the west/southwest on the backside of the high pressure.
With the upper level thermal trof moving through on Tuesday, much of the area looks to remain in the single digits. Tuesday afternoon winds will increase as the high moves into the Great Lakes keeping wind chills low but generally below zero.
Breezy northerly winds will setup tonight bringing more cold air south and we could see a brief period of freezing rain over Levy County around and shortly after sunrise, but overall amounts look very slim as the precipitation will be coming to end here at around the same time.
Going later into the day today, it appears that most of the areas should be above freezing for high temperatures, topping out from the mid 30s to lower 40s. This is due to a "warmer" SW downslope sfc-H850 wind developing as H500 height rises upstream from the main departing mid level trough fills in across the Panhandles region. This will result in at least temperatures getting above freezing. We actually will be a few degrees warmer for tomorrow with highs ranging from the upper 30s to upper 40s.
Temperatures as of 10 PM were in the lower 60s with the "warmest" temperature observation coming in at 65 degrees. The occasionally gusty northeast breezes we have seen tonight near 15 mph will slowly diminish overnight, but don't get too used to it as the next cold front will be here before we know it. From synopsis, breezes will slacken somewhat from now through Tuesday evening, before another cold front pushes through the area late Tuesday night into Wednesday morning.
Another clipper system moves southeast through the Central Plains Tuesday night and Wednesday bringing another cold front through the area. Temperatures on Wednesday warm up into the lower to mid 30s ahead of the cold front.
By later tonight, we'll likely see more valley stratus and freezing fog in the valleys. The MET and MAV guidance is predicting fog, and low temperatures will be well below freezing in many of the valleys tonight. The high clouds could throw a wrench in things, although we're thinking that the dry layer and inversion strength should usher in plenty of fog. No big pattern changes as high pressure remains in control, although the different wind direction could push some lower stratus into the coast Tuesday afternoon and evening. High pressure will strengthen into Wednesday with the 500 mb ridge centered right over southern Oregon and northern California.
An upper level trough is moving through the region as well. As the trough axis swings to the east tomorrow, winds will turn to the west, then southwest, allowing the airmass to moderate and temperatures to warm.
We will be monitoring this period for another potential Cold Weather Advisory, primarily 9 PM tonight through 9 AM tomorrow, when wind chills dip the lowest.
Dangerous cold tonight 20z WV satellite reveals a positively tilted upper trough just to our northwest. With the trough departing to the east, expect skies to clear and winds to decrease a bit, leading to above average radiational cooling conditions. Light snow potential Tuesday night into Wednesday Wednesday, next upper trough arrives from the northwest, bringing a fair amount of mid-level moisture with it.
- Warmer conditions return for late week into the weekend. Quick development of a lee trough will shift winds to the south and southwest overnight, with gusty winds possible again by morning.
An uptick in snow intensity has been taking place this evening due to the approach of the upper trough axis and associated stronger lift.
The axis of a trough is expected to sweep across today with cloud cover approaching in both directions. Strong high pressure over us, though giving us frigid conditions, is to thank for blocking this system from getting any closer. The entire area is again expected to remain below the freezing mark for highs.
07Z water vapor showed an upper trough swinging through central North America with another upper wave digging south over Alberta. Surface obs showed high pressure centered over KS and the forecast area with a very dry airmass over the region. Will keep the cold weather advisory intact with some wind expected to pick up mid-morning with the ridge axis moving east.
- Warmer temperatures through the end of the week. (Rest of today and tonight) The cold front is moving through northern Oklahoma with the band of moderate snow near the front. Most areas should at least approach if not rise above freezing on Tuesday afternoon.
An instability trough swings through into this evening. With the cooler low level temperatures and some winds to work with, wind chills may be able to approach -25F values, especially in an area between Laporte and Elkhart. Winds then pick up on Wednesday as the trough vacates the area and warm advection ensues. The best chance see us tick back above freezing is this weekend.
Some locations along the plateau will drop into the single digits but the majority of the area should be in the 10-15 degree range for the low temperature.
This evening into the overnight has a band of WAA moves in, then again Wednesday afternoon and evening behind a secondary cold front and associated CAA and steep low level lapse rates that develop.
Tomorrow, the arctic high pressure that is moving into our area tonight will continue to move east into the Midwest and Ohio River Valley. This will allow southerly winds to return at the surface, advecting warmer temperatures and higher heights into our area. This will help those on the Nebraska side warm up into the low 20s, with upper 10s expected as highs in western Iowa. By Wednesday, another trough dives south into the central CONUS from south-central Canada.
933 PM MST Mon Jan 20 2025 -Bitterly cold temperatures and wind chills continue into Tuesday morning -Clipper will bring warmer weather to the region Tuesday, followed by wind and light snow Tuesday night through Wednesday night. Several inches of snow possible in the northern Black Hills Water vapor shows long wave trof covering much of the CONUS with upper ridge folding into the Pac NW. Arctic high will quickly push south/east of the area tonight, with upper ridge building into the Northern Rockies and lee trof moving eastward. On Tuesday, warm westerly flow will gradually scour out any remaining Arctic air, with flat upper ridge moving overhead ahead of an approaching clipper.