Aikyam-Lab/Synoptic-Bench huggingface dataset:
Temps tonight will be borderline for a period of rain/freezing rain across our extreme northwest. A cold front moved through the area last night, now post-front low clouds are locked in place.
159 PM MST Wed Feb 23 2022 Upper level analysis and water vapor imagery depict two primary upper lows: one over the Hudson Bay and another centered over Nevada. A trough axis extends from the Hudson Bay low southwestward into the east-central MT southwestward into the southwest US. At the surface, high pressure is centered over northeastern SD and will remain fairly stationary before the southwestern low ejects eastward. As the southwestern low ejects eastward and the upper trough axis pivots through the forecast area, expect some light snow later this evening across the far southern portion of the forecast area.
1148 AM CST Wed Feb 23 2022 Arctic air continues to make its presence felt across the central Plains with a 1047mb high pressure system centered over the Dakotas. Later tonight and into Thursday, the large area of high pressure will move east into Minnesota, and a broad positively-tilted wave will move across the central Plains.
1022 AM PST Wed Feb 23 2022 Cold temperatures will continue today, but lighter winds and sunshine will help to make it feel warmer than yesterday.
Freezing rain and sleet will once again be possible tonight. Although dry air above this moist layer would usually suggest freezing drizzle, this air mass is cold enough to produce mostly sleet. As the high level clouds clear out this evening, low level moisture will come back with a vengeance on the caprock. A short wave trough will be approaching the area early Thursday leading to an increase in the jet level winds. Large scale lift will again increase from the increase in jet level winds but the atmospheric column will be extremely dry outside of the lowest 75-100mb. The resultant dry punch aloft will erode the stratus layer from southwest-to-northeast, with temperatures warming into the lower 50s to upper 30s across the southwestern South Plains and northeastern Rolling Plains, respectively.
Heavier precipitation will begin to shift east by late afternoon with a few lingering areas of very light snow across the north and a trailing edge of light sleet/freezing rain in far southeast Oklahoma/west-central Arkansas. Tonight, generally expect a lull in precipitation with the potential for mainly very light freezing drizzle as mid level dry slot moves in. (Tonight through Wednesday) As main upper trough axis approaches late tonight into Thursday morning. Areas of sleet and freezing rain will begin to increase again. Still the potential for Arkansas river valley to warm above freezing by early afternoon.
1057 AM MST Wed Feb 23 2022 Longwave trough remains idling in place across the Rockies through the next 36 hours, with lobes rotating through the region. Colder temperatures again keep snow production lower, with only an inch or two for the higher western mountains. Temperatures will remain very cold through the next 36 hours as the trough keeps the cold airmass in place.
McD Chattanooga Airport, TN 49 72 50 61 36 / 30 40 60 60 10 Knoxville McGhee Tyson Airport, TN 46 65 50 61 34 / 40 70 60 70 10 Oak Ridge, TN 44 63 47 59 33 / 50 80 70 70 0 Tri Cities Airport, TN 45 61 49 61 32 / 80 90 40 80 10.
1150 AM CST Wed Feb 23 2022 (Today and tonight) Certainly a much more convective morning than originally thought as storms with sleet, freezing rain, and even small hail at times continues to push north across the Big Country early this morning. Freezing line has continued south and will approach I- 10 by sunrise, meaning that most of the precipitation today will fall as some sort of wintry mix. Given the huge warm nose which isn't going anywhere, should be a mix of freezing rain and sleet for most areas. Again, freezing rain and sleet, with enough accumulation that the Winter Weather Advisory should remain in effect. Will need to keep a close eye on the northern and eastern Big Country, which will see the highest accumulation and will need to be monitored in case a Warning may be required.
1044 AM EST Wed Feb 23 2022 High pressure centered over the western North Atlantic supports moderate easterly breezes across the coastal waters of the Florida Keys. Skies are mostly sunny, aside from a small patch of clouds pressing northwest through the Lower Keys. The forecast calls for nil rain chance with highs in the lower 80s. High pressure centered over the western North Atlantic will stretch west across Florida into the Gulf of Mexico for the next several days.
Cold high pressure persists this morning, with sunny skies. Early this morning, the center of an Arctic high pressure extended from northeast Montana, through western North Dakota, and into central South Dakota, leading to clear skies and light winds across much of the forecast area. Aloft, flow across the state was zonal, with troughing digging across the southwest CONUS. Flow aloft across the region is expected to stay northwesterly in response to ridging building over the Pacific Northwest. As this ridging amplifies and the aforementioned Arctic high exits to our east, we begin a steady warming trend through the end of the week.
Although on Thu, the heavy rain band is expected to shift northward as this warm front moves, leaving areas largely around and north of I-40 with the highest threat of flooding. Another issue is our extreme northwest will be very close to some near freezing air tonight/early Thu. The temp structure does suggest a period of freezing rain but with SFC temps hovering around 32-33, not likely to have many impacts from this. Will however add at least chance of freezing rain up there.
***UPDATE*** A cold upper trough continues over the west with the low center in central NV. Temperatures will remain quite cool, maybe a degree or two warmer than yesterday at most. ***From Previous Discussion*** Chilly low temperatures will set in overnight with near freezing values spreading into the Central and Santa Barbara Coasts, Santa Clarita Valley, and eastern Ventura County Valleys. A change is in store for Thursday as flow shifts to offshore and temperatures begin to trend warmer.
The atmosphere is in a rather static state for this time of year with a strong upper-level ridge stretching from the Central Gulf, across Florida, and into the Atlantic. Above average temperatures, with the possibility for some records to be broken, remains likely with this high pressure.
254 PM CST Wed Feb 23 2022 18z data has high pressure over the northern Plains while a storm system continues to develop in the southern Plains.
Winds will lighten up through the day as high pressure builds in. This may not be the case across southeast MN where a slightly warmer column suddenly yields a considerably deeper DGZ (10-15 kft deep). QPF spread is still quite large considering the high snow ratios where only a few hundredths here or there could result in an inch of accumulation difference. Kept the QPF forecast very near WPC and the ensemble mean, resulting in accumulations of 1 to 3 inches and the highest amounts in the southeast where dendrites are most likely. Late in the morning, cigs lower (but remain VFR) with the highest threat for some -SN for southern terminals remaining just outside the forecast period.
154 PM CST Wed Feb 23 2022 The cold front has nearly stalled out along the I-20 corridor. Weak 5h ridging will continue over the southeast into Thursday within a wide expanse of southwest flow atop the shallow Arctic air across the south central states into the lower OH valley.
Currently, while there are still pockets of light freezing drizzle or light sleet, most of the precipitation from overnight has ended. Therefore, will keep the increasing chance of sleet and freezing rain in the forecast tonight, with the best chances in our Big Country area. We will again have a chance for light accumulations of this sleet and freezing rain of up to a tenth or two. For now, have gone generally cooler than the GFS, but not quite as cool as the NAM for highs.
921 AM PST Wed Feb 23 2022 It was a cold one last night, although a tad bit warmer than what was in the forecast 24 hours ago. We still have a freeze warning out for tonight along the coast as we're expecting temperatures to drop below freezing yet again in most areas. Areas like Brookings and Gold Beach have a 40% chance to remain above freezing tonight. Temperatures will also trend warmer through the end of the week; since days are starting to get longer and the sun angle is a bit higher in the sky.
Ridging over the Gulf of Mexico and Florida in the mid and upper levels will further stabilize the environment. More of the same but even warmer still.
1241 PM EST Wed Feb 23 2022 Much colder early today with patchy freezing drizzle ending as arctic flurries and light lake snow showers spread in from the west.
High pressure will meander east over our area this evening, dropping our winds to under 10 MPH.
118 PM EST Wed Feb 23 2022 Colder and drier air will filter into the region tonight behind the cold front.
/Updated at 1126 AM CST Wed Feb 23 2022/ High pressure over the southern Gulf will keep zonal westerly to southwesterly flow through the mid and upper levels through Thursday. High temperatures today will be in the upper 80's in the far southeast to the lower 50's in the far northwest. Southerly flow south of the front will keep warmer air in the south. with areas north of the front experiencing cooler temperatures from northerly flow and from the overcast clouds through the day. High temperatures on Thursday will be warmer than normal for this time of year.
245 PM EST Wed Feb 23 2022 Fortuitous switch from cyclonic to anticyclonic flow trajectories is now taking place at press time as a midlevel cold front pushes southward through Southeast Michigan. Cold drainage flow off the high will result in cold night time temperatures. Did lower mins tonight a degree or two with readings in the lower teens to upper single digits.
The southerly winds will take over again, pushing the now warm front back up and through the forecast area tomorrow. A deep upper trough then finally starts to eject out of the SW and across the region, pushing the front back to the south by late afternoon/evening. The only concern for a more active afternoon is that persistent southerly flow holding the front/cooler air to the north. though parameters are less impressive and temps even cooler.
238 PM CST Wed Feb 23 2022 A weak wave ahead of a developing trough in the Rockies will bring a small chance for snow to areas near the Missouri River this evening and early night time hours. Otherwise cold high pressure will be in place but with the main trough lifting onto the Plains overnight clouds will increase so radiational cooling will not be maximized. Instability does not look to play a major role with this system, but favorable temperatures aloft for snow as well as lighter winds in the lower 5000 feet or so of the atmosphere should help maximize snow ratios, which will likely be close to 20:1.
The first wave will be mainly all snow with a mix of sleet and possible freezing rain in the far southeast parts of the CWA. As warmer air lifts northward across a frontal zone, the sleet mix will push north of I-70 during the afternoon. This will cause the precip to fall as all liquid, resulting in freezing rain over eastern parts of the CWA. However, areas along I-55 could see a mix of freezing drizzle/rain and snow, making for a slippery commute Thursday evening. A winter weather advisory will be issued for the entire CWA, with freezing rain and sleet along and south of I-70, snow and freezing rain along and east of I-57, and all snow west of I-57. Temps will start on the cooler side but then warm back up.
Below average temperatures will persist through the week with sub-freezing overnight and early morning temperatures across the interior. Afternoon satellite imagery shows some of yesterday's snow on Bay Area peaks too, but it continues to dissipate with warmer temperatures. Satellite also shows afternoon cumulus popping over the higher terrain.
Initially, patchy freezing drizzle may develop, especially across southeast Oklahoma. Farther northwest, patchy freezing drizzle appears less likley due to colder temperatures in the subfreezing low-level layer (i. However, there are signs some warming may occur that could result in at least some chance of freezing drizzle. The highest chance for significant precipitation is southeast of I-44 and east of I-35. While most of the precipitation today has been sleet in our area, there is a chance freezing rain may occur or mix with sleet across far southeast Oklahoma tomorrow (there might be subtle warming aloft). Even so, there should not be enough freezing rain to cause significant tree damage or disruption to power.
529 PM CST Wed Feb 23 2022 A weak wave ahead of a developing trough in the Rockies will bring a small chance for snow to areas near the Missouri River this evening and early night time hours. Otherwise cold high pressure will be in place but with the main trough lifting onto the Plains overnight clouds will increase so radiational cooling will not be maximized. Instability does not look to play a major role with this system, but favorable temperatures aloft for snow as well as lighter winds in the lower 5000 feet or so of the atmosphere should help maximize snow ratios, which will likely be close to 20:1.
417 PM MST Wed Feb 23 2022 Upper level analysis and water vapor imagery depict two primary upper lows: one over the Hudson Bay and another centered over Nevada. A trough axis extends from the Hudson Bay low southwestward into the east-central MT southwestward into the southwest US. At the surface, high pressure is centered over northeastern SD and will remain fairly stationary before the southwestern low ejects eastward. As the southwestern low ejects eastward and the upper trough axis pivots through the forecast area, expect some light snow later this evening across the far southern portion of the forecast area.
Today and Tomorrow: Southwesterly flow is in place across the central CONUS ahead of a digging mid-level trough over the southwestern CONUS, with that trough being the main weather maker for the forecast period. The main show doesn't get started until tomorrow where the aforementioned trough out west pushes eastward into the Central CONUS, bringing widespread light snowfall to the area by mid-to-late morning. Snowfall guidance has been rather consistent with keeping amounts on the low end.
348 PM CST Wed Feb 23 2022 Back to the trough of the temperature wave we go as high struggle to reach just over 20 degrees. Areas north of US-50 are expected to see mainly snow with places south of US-50 potentially seeing a little bit of freezing drizzle and/or sleet mixed in. Model vertical profiles show a slightly favorable environment toward mixing freezing drizzle and/or sleet in with snow as the warm nose aloft approaches 0C and the vertical column resides between -1C and -12C, just warmer than the dendritic growth zone. If the 0C line shifts further north, more freezing rain and sleet will be mixed in the precipitation.
Surface ridging centered over eastern ND has been nosing eastward through the day. While light lake effect held on a little longer than expected across the west and central it has drastically waned over the last couple hours as the ridge pushes east, winds have become more disorganized and inversion lowers. Still a few more hours of disorganized lake effect to go over the east before the ridge wins out and that goes away.
Looking at model soundings, the northwest part of our area will likely see some sleet and freezing rain this evening with the onset of precipitation. An area of precipitation is currently making its way across the Tennessee River, and some of this precipitation is going to start off as freezing or frozen, especially at CKV.
The cold front has nearly stalled out along the I-20 corridor. Weak 5h ridging will continue over the southeast into Thursday within a wide expanse of southwest flow atop the shallow Arctic air across the south central states into the lower OH valley.
Scattered rain and snow showers will continue into this evening as the center of a cold low pressure center passes across southern Nevada. By the weekend, a high pressure ridge will build over the southwest causing temperatures to warm back to near normal levels. Early afternoon satellite imagery shows the base of the upper level trough moving across southern Nevada. Breaks in the clouds this afternoon are allowing for some surface heating, and given the cold air aloft associated the the trough, scattered instability showers have developed across Clark San Bernardino and Mohave counties. Snow levels have fallen to below 3000ft area wide so light low-elevation snow may mix in at times except in the lower Colorado River Valley where only liquid precip is expected. As the low lifts out later this evening and tonight the precip should come to an end.
Even areas adjacent to the coast will reach the low to mid 30s.
Along with the cold wind chills, light snow is expected to develop after midnight as the upper trough currently moving through the Intermountain West moves east of the Central Rockies tonight and across the central High Plains Thursday morning. The best lift associated with the upper trough occurs between midnight tonight and mid-day on Thursday, and will correspond to the highest snowfall accumulations across the area. Snow tapers off Thursday afternoon as the upper trough moves east of the area.
Cold air will slowly erode across the Northern Rockies Thursday through the upcoming weekend, with relatively warm high pressure overhead.
536 PM MST Wed Feb 23 2022 The deep upper level trough is beginning to push east across the Great Basin this afternoon. After this evening's wave, there should be one more wave late tonight/early Thursday morning associated with the upper trough/cold pool passage.
237 PM MST Wed Feb 23 2022 The deep upper level trough is beginning to push east across the Great Basin this afternoon. After this evening's wave, there should be one more wave late tonight/early Thursday morning associated with the upper trough/cold pool passage.
Lows of 5 to 15 are expected in the lower valleys, with a few degrees below zero possible for lower valleys with at least a few inches of snow cover remaining. Thursday looks to see a rebound in afternoon temperatures of around 10-15 degrees as some increase in afternoon mixing (especially northeast CA and far western NV) ensues with another cold front approaching from the north.
With temperatures forecast to warm above freezing after 12z in this area, opted to run this segment of the advisory through 15z. Given warm pavement temperatures here, travel impacts are most likely to occur on untreated bridges and overpasses.
532 PM EST Wed Feb 23 2022 Colder and drier air will filter into the region tonight behind the cold front.
444 PM MST Wed Feb 23 2022 Early afternoon GOES-W WV imagery showed a upper level trough centered over the Great Basin. The upper trough to the southwest will weaken as it tracks east through the Central/Southern Rockies tonight and Thursday morning. This system will increase the low level upslope to produce periods of light snow tonight, with snow tapering off from west to east Thursday morning.
18z data has high pressure over the northern Plains while a storm system continues to develop in the southern Plains.
High pressure remains overhead this afternoon with clear skies and light winds across the Northland.
Cold front is SE of all TAF sites, with the exception of the Acadiana terminals, although recent satellite/sfc obs indicate the boundary is nearly over LFT.
150 PM PST Wed Feb 23 2022 Cool and dry into the weekend with widespread freezing low temperatures in the early morning hours. Temperatures trend warmer towards the end of the week. Temperatures this afternoon are trending a near or a few degrees cooler than yesterday, with highs expected to reach into the mid 50s across the Valley, and into the 20s and 30s in the mountains. High pressure returns over the area tonight bringing clear skies and light winds, leading to the coldest overnight lows of the week for much of the area. The dry weather and cooler weather continues into the weekend with a few more nights of near or below freezing temperatures in the Valley.
918 PM EST Wed Feb 23 2022 Colder and drier air will filter into the region tonight behind the cold front.
Tonight, the base of the upper trough will advance from srn CA and AZ to across the Four Corners. As the upper trough moves over CO and NM after midnight, snowfall is forecast to develop northeastward across much of western NE later tonight ahead of an H7 trough axis. On Thursday, the upper trough will move eastward, with light snow ending from west to east in the afternoon. All deterministic and ensemble guidance is showing a strong signal for upper level ridging with a much warmer, though continued dry, pattern.
230 PM MST Wed Feb 23 2022 Early afternoon GOES-W WV imagery showed a upper level trough centered over the Great Basin. The upper trough to the southwest will weaken as it tracks east through the Central/Southern Rockies tonight and Thursday morning. This system will increase the low level upslope to produce periods of light snow tonight, with snow tapering off from west to east Thursday morning.
We have already seen thunder snow, thunder sleet, and thunder freezing rain across eastern Arkansas. We have seen reports up to half an inch of sleet in 30 minutes, which has accumulated on the bridges. This would reduce the amount of sleet drastically, but result in freezing rain accumulations approaching a half an inch by tomorrow morning across the winter storm warning area.
Wind speeds will start to pick up, especially in the northwest CWA after midnight in response to a strengthening low pressure system in southern Colorado. An upper level closed low in southern Nevada is expected to open up and weaken as it moves east northeast across the 4-corners by early Thursday morning and into the central Plains by Thursday afternoon. The cold air will try to erode over the southwest Texas Panhandle Thursday afternoon in the form of a warm front. At this point, have gone with a compromise between the warmer and cooler models.
733 PM EST Wed Feb 23 2022 During the next 24 hours or so an upper ridge centered in the Gulf of Mexico and covering most of the Gulf region will ease to the northeast. 3 inches and confined to the low levels. High pressure stretches across the waters with a relaxed gradient.
Although we'll switch on some weak downslope warming tonight, lingering cold and high pressure will still let temperatures drop into the negative teens. The main weather of concerns outside of lingering cold is blowing snow potential along the foothills west of Billings as high pressure lingers over eastern Idaho and low pressure lee-side of the Rockies moves into area area, creating a pressure gradient, albeit a weak one, to bring some wind speeds into the upper teens.
In addition to the strong winds and precipitation, much cooler temperatures can be expected tomorrow with readings remaining below average through the weekend.
949 PM EST Wed Feb 23 2022 The forecast remains on track this evening, with a high pressure ridge axis continuing to stretch into the Florida peninsula from the Atlantic. Onshore flow continuing, with lows in the low 60s, with upper 50s possible in rural areas. High pressure and dry conditions continuing over the local waters.
Brisk northerly winds will make for a cold day, with highs struggling to reach the freezing mark. Brisk northerly winds will make for a cold day, with highs struggling to reach the freezing mark. Today through Thursday night Trof continues to move across the Great Basin today, bringing isolated to scattered snow shower activity this morning, tapering off this afternoon. Ridging will try to push in from the West on Thursday but a slider trof will prevent that from happening as it quickly clips northeast Nevada. The system's cold front, however, will bring another reinforcing shot of cold air, and therefore the lows on Thursday night are expected to remain in the single digits.