Aikyam-Lab/Synoptic-Bench huggingface dataset:
1042-1044 MB arctic high pressure is over our CWA, with very cold air mass lingering. Guidance indicates gradual moderation of the air mass as the mid/upper low over far southwest Ontario transitions east today through Monday, however it will remain bitterly cold with sub zero temperatures likely to continue. The deepest cold aloft will be transitioning east today, so it may not be a repeat of the convective streamers yesterday and soundings are a bit dryer with more of a subsident axis west of the upper low transitioning into our region.
Through Monday, this area of high pressure will slide southeast weakening to around 1032mb by 00Z.
and W Atlantic ridging to the east. Ridging persists through the week while a series of disturbances propagate through the flow bringing bouts of unsettled weather to our area as they interact with a lingering stationary surface frontal boundary into midweek. Activity will diminish during the evening as disturbance aloft pulls away leaving surface boundary across the Southeast, which will produce additional rounds of showers/storms during the first half of the week as additional disturbances swing across the area ahead of the main trough axis that remains across the central CONUS.
211 AM MST Sun Feb 14 2021 Dangerously cold air continues through the weekend as arctic high pressure resides over the region.
Looking at our regional synoptic pattern, the subtropical ridge remains anchored over the western Atlantic while a stationary front occupies the central Gulf of Mexico, extending across northern Florida and paralleling most of the United States east coast.
336 AM MST Sun Feb 14 2021 Dangerously cold air continues through the weekend as arctic high pressure resides over the region.
501 AM MST Sun Feb 14 2021 The upper level trough continues to move southeast from the Four Corners area this morning. The deeper clouds also weren't that solid as there were pockets of drier air, including a persistent one over most of the Denver area that was probably related to gentle downsloping above the low level cold air. Northwest winds will start to pick up over the higher elevations after midnight, with a little ridgetop snow starting again and beginning to push the cold air out of the higher foothills. The cold airmass and fresh snow will make Monday another cold day with single digits and teens across the lower elevations of eastern Colorado.
327 AM MST Sun Feb 14 2021 Eastward migration of a very potent upper level low over western Ontario is drawing the deepest core of the arctic high pressure eastward but still expect a very cold day. High temperatures today will be similar to previous days as approaching clouds across the western areas will limit the already limited solar warming but 850mb temperatures show a slow rise in the afternoon and evening hours and tonights lows look to be 10 to 15 degrees warmer as a result.
We may see a break or lessening of snow intensity this afternoon before it picks back up again this evening as a stronger upstream upper trough approaches. All in all, given the higher snow to liquid ratios we expect, will see a general 4 to 6 inches.
Compared to 24 hours ago, most Valley communities are running about 5 to 10 deg F cooler as of midnight. Best chance for any sort of light precipitation in the afternoon/evening hours will be far northern Sacramento Valley and the Coastal Range as a warm front approaches the region.
A series of weather systems will result in cooler temperatures and breezy to locally windy conditions through the middle of the week.
545 AM CST Sun Feb 14 2021 Arctic high pressure to the northwest will bring more frigid temperatures and bitterly cold wind chills to central and southeast Illinois, for today and Monday. 1043 mb Arctic high pressure was centered over the northern Plains early this morning. This should result in a widespread 2-4" snowfall, with the higher amounts southeast of the IL River.
Some potential for snow with warmer temperatures later in the week. Another quiet and cold night across the region this morning with a ridge of high pressure over North Dakota, with northwest flow across the area. The winds have kept us a little warmer than last night at this time, but they are also producing wind chill values as cold as 46 below.
942 AM MST Sun Feb 14 2021 Dangerously cold air continues through the weekend as arctic high pressure resides over the region.
We remain just on the western periphery of a subtropic ridge that extends westward across the Atlantic. To our northwest a broad low pressure sits over the central Gulf of Mexico, south of the mouth of the Mississippi River Delta. A cold front extends south-southward from the low into the southern Gulf. Current temperatures are near 80 degrees with dewpoints in the lower 70s. Due to fact that we sit on the western periphery of the subtropical ridge, our low level mean layer wind (1000-700 mb) remains from the south. This will transport relatively drier air from the northwest Caribbean and will act to suppress rain chances, especially for the Lower Keys. Again this would be most true for the Lower Keys.
We are still east of the main trough axis aloft, but the perturbations that brought us the light snow have since passed through the area. Monday will remain very cold as we remain centered under the upper trough.
Temperatures remain in the low 20s to teens for many places, so the snow is a dry, light, fluffy texture which should easy fly about.
As the high has shifted ewd, return flow has begun over nern WY, maintaining very cold to dangerous wind chills into the aftn. Low-level thermal troughing will be slow to depart (slower than prior guidance suggested), so will likely see another morning or two of below zero lows for much of wrn/cntrl SD.
As described in previous discussions, tonight the high pressure will be centered over our forecast area. That being said, winds in the heart of a high pressure center are light to calm, which means wind chills (which are a combination of temperatures and wind speed) will likely be a tinge "warmer" than they were overnight and this morning. Some spots, particularly urban areas where more friction hinders winds slightly and temps have the potential to be a degree or two warmer, may only briefly touch warning-levels. By 10 AM Monday, wind chills should improve to the Advisory category or even warmer.
Radar observations show light snow is lingering over portions of our area, but this will dissipate over the next few hours as the upper level trough axis approaches and forcing for ascent diminishes. Surface observations indicate temperatures are ranging from -2 to +3 degrees at noon, with wind chills in the -15 to -23 degree range, and this bitter cold will not be going anywhere today as the low stratus deck and northeast winds reinforce the arctic air. Overnight tonight, the upper level trough will move over the central and southern plains, with large scale descent immediately behind it that will begin to erode the low stratus deck from west to east.
Most area road temperatures are below freezing. For central areas, a mixture of sleet(primarily) and freezing rain.
Arctic high pressure continues to push southeastward today, but with how large and prolonged the brutally cold airmass been it will take some time to scour out the cold.
The first round of snow will be tonight in a zone of increasing low/mid trop frontogenetical forcing positioned out ahead of the main upper trof, that by 12z Monday should be over the central and southern Plains.
Still getting reports of some patchy freezing drizzle and also some light flurry activity western half. As the warm nose develops it will not dislodge the subfreezing air through the 1st 3 kft or so.
On Monday, high pressure will hold over the region with continued southerly flow creating warm humid conditions, a sharp departure from the remainder of the CONUS.
A few of the highlighted areas (mainly across northern slopes / latitudes as well as portions of West Elk / Sawatch Mountains) sit on the low end of criteria as of early this morning. The trough axis and associated cold front is evident from surface and remote sensing observations this morning.
239 PM CST Sun Feb 14 2021 Cold, arctic high pressure will settle south tonight and should bring the coldest morning temperatures during this long stretch of cold weather that the area has been stuck in. High pressure will remain locked in place on Monday so temperatures will again remain below zero through the day.
With the trough axis currently oriented north to south from eastern New Mexico, to just east of El Paso, lift associated with the trough will continue to affect the area for several more hours. The heavier snowfall will move into areas southeast of an Abilene to Sonora line during the evening hours as the trough axis moves through our CWA, and then completely out of the area by Monday morning. Farther south, along the I-10 corridor, temperatures were in the 15 to 20 degree range with wind chill values ranging from the low single digits to around 15 degrees.
Models bring in some lower moisture into the mountains later tonight and Monday, so will get some "chance" pops in the high mountains after 06Z tonight, then some "likely"s by Monday afternoon. Concerning the winds and wind chills, will leave the highlights going through Monday at 18Z with the cold air mass in mind. Concerning fog tonight, the models, including the high res.
A weak Pacific trough has spread more clouds across Oregon this morning, with radar showing faint echoes in the Upper Weiser Valley indicating flurries. The clouds extend out into the Pacific to a stronger trough around 45/140. The stronger trough will bring snow again late tonight and Monday morning as it moves directly through our CWA. The system's warm front will pass through southern areas late Monday morning and temps will rise to the upper 30s. A cold front will pass through late Monday bringing slight cooling again.
High pressure will temporarily build across the area through tonight.
After a relative lull overnight, model consensus supports an additional zone of deformation snow rotating northeast across eastern/southeast KS, associated with the ejecting upper low, with additional light accumulations likely Monday morning into the afternoon.
High pressure continues to slowly slide southeast of the area. Currently, Arctic High pressure is situated over central portions of Lake Sakakawea. Upper level low is over southwest Ontario.
As a result, weak low level warm air advection will lead to slightly warmer temperatures than this past morning.
/Issued 156 PM CST Sun Feb 14 2021/ Some light snow will be possible for about the southeast half of the Texas Panhandle this evening as the upper trough moves across and east of the area.
We will be ending the highlights for all but the far southern tier of zones with the afternoon package.
The lead disturbance ejecting out of a deep low pressure trough over the southwest is already bringing snow from around the Illinois River westward in a frontogenetical region, while an additional disturbance currently heading into southern Missouri should arrive this evening and spread snow throughout central and southeast IL, becoming a bit heavier overnight.
Across our region, temperatures remain in the 30s with the freezing line from Fort Polk to Lafayette northward at this hour. With the cold surge of cold arctic air continuing to move slide southward, freezing rain mixed with sleet will begin this evening, with the bulk of this falling between Midnight and 9 AM Monday across Southeast Texas into Central and Southern Louisiana. 35 inches, which will most likely cause significant icing across all bridges, trees, and eventually roadways as the temperatures likely to remain in the 20s areawide Monday.
In addition the warm and moist air mass overriding the cooler Gulf waters will also support some sea fog development as well and a Dense Fog Advisory issuance may be required for portions of the forecast area and adjacent coastal waters by early Monday morning. On Monday another short wave trough will approach from the west. High pressure will hold over the region through Monday. A warm and moist air mass overriding the cooler Gulf waters may support some dense sea fog development the remainder of tonight with south winds around 10 knots. On Monday south winds will increase into the 15 to 20 knot range ahead of an approaching cold front and Cautionary headlines may be required by afternoon. The cold front will move across the waters Monday night with a further increase in winds and seas producing hazardous boating conditions.
Many many reports of heavy sleet west of I-65, along with freezing rain/drizzle east. Many roads and bridges already treacherous, and that will likely only get worse overnight.
Areas along and west of I-25 will remain slightly warmer with mild downsloping so have left them in an advisory. Models bring in some lower moisture into the mountains later tonight and Monday, so will get some "chance" pops in the high mountains after 06Z tonight, then some "likely"s by Monday afternoon. Concerning the winds and wind chills, will leave the highlights going through Monday at 18Z with the cold air mass in mind. Concerning fog tonight, the models, including the high res.
442 PM MST Sun Feb 14 2021 The trough that produced widespread snowfall yesterday and today is currently lifting out over the southern plains. The coldest areas will be along the highway 40 corridor where highs are struggling to get out of the single digits. The trough axis will still be centered over the Great Basin and so will the large-scale lift. The showers could reach some of the higher valleys, but with the lack of forcing rates may stay relatively light. Tomorrow night the trough passes over the area with the forcing becoming maximized between midnight and sunrise. Models have been showing that the trough will be gradually deepening as it tracks over the Four Corners region.
A cold front will move southward across the district on Presidents Day and bring light precipitation to mainly the mountains into Monday evening.
At 500 mb, the cold pocket associated with the low over southwest Ontario was at -45 C. An area of cold high pressure at the surface was centered over the border area of SD/ND/MN at about 1043 mb, but the high stretched from southern Canada down into TX.
Red River valley and E ND should maintain a light SW wind 5-8kts and therefore a bit "warmer" lows. Will begin to see the affect of the stronger sun now and black fields in the RRV, so high temps may err on the warmer side. However you look at it, warmer temperatures are ahead! As is expected, an occasionally breezy south-southwesterly wind will bring around normal temperatures by midweek, along with potential to see a rise up to above normal values by the weekend.
With temperatures this low, frostbite may occur in less than 30 minutes on exposed skin and hypothermia is possible. If skies clear Monday we may warm up a bit up to the high teens and low 20s by the afternoon.
215 PM MST Sun Feb 14 2021 The trough that produced widespread snowfall yesterday and today is currently lifting out over the southern plains. The coldest areas will be along the highway 40 corridor where highs are struggling to get out of the single digits. The trough axis will still be centered over the Great Basin and so will the large-scale lift. The showers could reach some of the higher valleys, but with the lack of forcing rates may stay relatively light. Tomorrow night the trough passes over the area with the forcing becoming maximized between midnight and sunrise. Models have been showing that the trough will be gradually deepening as it tracks over the Four Corners region.
The high will continue to slowly drift southeast and this will allow the arctic air to gradually lose its grip on the area. The west will be warmer than the east with highs in the west reaching the 20s, while the east will stay in the single digits.
The warmer westerly flow will help to slowly mix out the entrenched arctic air and allow snow levels to rise. The lower elevations of north central Idaho will experience some accumulating snow tonight into Monday morning, but by the afternoon snow levels appear to climb above the Camas Prairie.
However, can't rule out freezing rain occurring and a change over to snow late Monday as the system moves out. For areas southeast of Tupelo, freezing rain will be the main threat with ice accumulations expected to be over a quarter of an inch.
513 PM CST Sun Feb 14 2021 Cold, arctic high pressure will settle south tonight and should bring the coldest morning temperatures during this long stretch of cold weather that the area has been stuck in. High pressure will remain locked in place on Monday so temperatures will again remain below zero through the day.
With temperatures at and above freezing for the southern terminals currently, carried VCSH. Areas near KAEX have already reported -FZRA and they are already below freezing. Across our region, temperatures remain in the 30s with the freezing line from Fort Polk to Lafayette northward at this hour. With the cold surge of cold arctic air continuing to move slide southward, freezing rain mixed with sleet will begin this evening, with the bulk of this falling between Midnight and 9 AM Monday across Southeast Texas into Central and Southern Louisiana. 35 inches, which will most likely cause significant icing across all bridges, trees, and eventually roadways as the temperatures likely to remain in the 20s areawide Monday.
1059 PM MST Sun Feb 14 2021 The trough that produced widespread snowfall yesterday and today is currently lifting out over the southern plains. The coldest areas will be along the highway 40 corridor where highs are struggling to get out of the single digits. The trough axis will still be centered over the Great Basin and so will the large-scale lift. The showers could reach some of the higher valleys, but with the lack of forcing rates may stay relatively light. Tomorrow night the trough passes over the area with the forcing becoming maximized between midnight and sunrise. Models have been showing that the trough will be gradually deepening as it tracks over the Four Corners region.
At KASD, KGPT, KNEW, KMSY, and KHUM, temperatures are expected to remain above freezing, and a moderate rain with prevailing IFR visibilities and LIFR ceilings is forecast through the end of the period. At KMCB, KHDC, and KBTR, a shallow pool of below freezing air will be in place in the lowest few thousand feet of the atmosphere. A mix of sleet and freezing rain is forecast for these terminals with significant icing concerns in place.
1043 PM CST Sun Feb 14 2021 Cold, arctic high pressure will settle south tonight and should bring the coldest morning temperatures during this long stretch of cold weather that the area has been stuck in. High pressure will remain locked in place on Monday so temperatures will again remain below zero through the day.
Seeing some light snow bands working across southeast Oregon and portions of southwest Idaho this evening along the leading edge of a warm front. A steadier and at times heavier snowfall will accompany the warm frontal passage Monday morning. Precipitation stays all snow to valley floors through mid- morning, with the lowest elevations along the Snake River possibly mixing earlier Monday morning. Surface winds mostly southeast 10 kts or less, increasing to 10-15 kts Monday morning, then becoming west to northwest 10-20 kts following a cold front Monday afternoon.
The Evening Update: Warm frontal precip is pretty light with weak radar returns moving SEwd over our CWA.
Aside from high snow rates which could exceed 1"/hr, impacts will be augmented by strong north winds as we lie between 1010 mb low pressure tracking up the Appalachians and 1040 mb Arctic high over MN.
Back door cold front associated with the arctic blast across the central part of the CONUS has pushed into southeast Arizona this evening. The cold front will likely not make it as far as Tucson overnight, but still looking at much colder lows area wide, likely the coldest of this month so far for most areas. Last freezing low at TIA was back on Jan 10th when the low was 30.
In contrast, the Florida Keys are on the other side of the cold front over the Central Gulf, with the 00z KEY sounding showing deep S-SW flow aloft. Then by Monday evening, we will be watching the slug of moisture that is currently rounding the subtropical ridge near the Cayman Islands. With such rich moisture, and a cold front trying to push into the eastern Gulf, there should be quite a blossoming of showers and perhaps thunderstorms on late Monday and Monday night. Satan Shoal buoy only shows 1-foot seas, but Pulley Ridge (88 NW of Fort Jefferson) is showing 4-foot seas from the southwest. Through Monday, the waters will lie between high pressure south of Bermuda and low pressure over the western and central Gulf.
With the trough and associated jet remaining largely overhead through midweek, a long duration winter storm will bring somewhere on the order of 20 to 30 inches (potentially more) to portions of the northern and central Utah mountains.
235 AM CST Mon Feb 15 2021 A mid/upper trough across the Southern Plains is progged to lift east and northeast towards the area early this morning. We continue to sit under the H85 thermal trough within an arctic airmass that spans across the central CONUS. Arctic high pressure will remain wedged in across eastern Kansas tonight and with a few breaks in the clouds we are expecting a continuation of record setting cold with lows in the ten to 15 below range for most areas. Accumulating snow appears likely once again although the highest probabilities are expected to remain just south of the area.
/issued 543 PM CST Sun Feb 14 2021/ A winter mess will best describe this TAF forecast as we transition from periods of freezing rain mixed with sleet to all snow later this evening and through Monday from west to east across our airspace.
Many many reports of heavy sleet west of I-65, along with freezing rain/drizzle east. Many roads and bridges already treacherous, and that will likely only get worse overnight. Middle Tennessee is going to be divided between snow and freezing rain for the remainder of tonight and tomorrow, with freezing rain initially occurring across Nashville Metro and areas east, and more snowfall occurring west of Nashville. However, CSV may see a brief period of rain tomorrow afternoon as temperatures rise above freezing for a few hours.
However, some light freezing rain/drizzle will be possible in Morgan/Scott/Campbell with a couple hundredths of ice accumulation possible. The Warning/Advisory areas will remain unchanged, as will the Freezing Fog Advisory in SW VA. CDG Chattanooga Airport, TN 42 28 39 25 51 / 90 80 10 0 20 Knoxville McGhee Tyson Airport, TN 43 31 37 25 47 / 90 90 20 0 20 Oak Ridge, TN 40 28 36 23 46 / 90 100 10 0 20 Tri Cities Airport, TN 52 35 37 24 49 / 60 90 20 0 20 TN.
I am going to bet that we see some thunderstorms develop south of the warm front that stretches across North Florida this morning. That is especially the case late this afternoon as the cold front in the Central Gulf gets closer. Fog is pooling just to the south of a warm front and it is impacting TPA.
Currently, High pressure is situated over northeast South Dakota with a southerly return flow over eastern Montana and extending into the western Dakotas.
Northerly winds should relax with a fair amount of sunshine returning, but the frigid air and snow-pack will likely keep all counties below freezing for a max and northeast counties struggling to get out of the teens. For tonight, models have trended lower on cloud cover and the lower bounds of temperatures with mostly light winds for tonight will lead to possibly the coldest low temperatures since the 1989 Arctic blast event.
505 AM CST Mon Feb 15 2021 An unusual high impact winter weather event is underway for the forecast area with a mix of accumulating freezing rain, sleet, and snow, along with bitter arctic cold.
Conditions do not look particularly favorable for strong downslope winds along the lower eastern Sierra slopes and Owens Valley, but will continue to monitor.