Aikyam-Lab/Synoptic-Bench huggingface dataset:
Adjusted sky cover in northwest Wisconsin to account for the low clouds drifting southwest from Upper Michigan. Summary: Warmer temperatures expected with a return to normal by the weekend. The remainder of the week the jet stream will make a slow advance northward helping to bring warmer air to the north, but the Northland will still be 5 to 10 degrees below normal.
The arctic ridge will move east out across western and eventually central Kansas tonight. The return flow will only recirculate the arctic airmass (not a warming wind direction), and with an expected increase in stratus cloud cover by afternoon, we will likely not see afternoon temperatures much warmer than today, unfortunately.
516 PM CST Mon Feb 15 2021 Summary: Warmer temperatures expected with a return to normal by the weekend. The remainder of the week the jet stream will make a slow advance northward helping to bring warmer air to the north, but the Northland will still be 5 to 10 degrees below normal.
/issued 245 PM CST Mon Feb 15 2021/ WV imagery shows the upper trough that brrrrought beaucoup snowfall and bitterly cold temperatures/wind chills to West Texas and Southeast New Mexico is now pivoting up into the MS Valley. As sfc ridging moves into the Central Plains overnight, return flow will develop, and should bring temperatures above freezing Tuesday afternoon for much of the area for the first time in days. Changeover to liquid and warmer temperatures should start melting the snowpack, but this will be a double-edged sword as a hard freeze is expected in this area Tuesday night, turning anything liquid back into ice. Meanwhile, an upper trough will arrive Tuesday night, and dig down into the Big Bend Area overnight.
Then, look for another wave to arrive Tuesday afternoon which would have the highest chance of producing more significant travel impacts. Tuesday will see warmer temperatures in most areas as we really try and break the inversion over the plains with an increasing north to south pressure gradient. Most of the rest of the plains will see 20s and 30s, while the far northeast corner will likely stay locked in the teens and too far east of the lee trough.
Despite the snowpack, not seeing much if any indication of freezing fog development overnight so have left it out of this terminal package.
A broad region of generally light to locally moderate snowfall is wrapping around a mid-level low pressure cell lifting northeastward along the Kansas Turnpike This low continues to lift into Missouri tonight and should result in a rapid end to the snowfall this evening. Did extend the winter weather advisory through 6 pm given the potential impacts on any evening commuters, but the dearth of moisture, plate ice crystal structure, and lack of aggregation is keeping snow ratios on the lower side. While winds lessen with the approaching ridge, temperatures overnight are progged to plummet once skies clear.
Given the high snow to liquid ratio (20+:1), snow is expected to shift pretty easily through tonight. Low pressure will exit east towards New England Tuesday while expansive ridge spreads south from the Upper Midwest along the Mississippi River Valley. This ridge axis will shift across Illinois late Tuesday evening.
An Arctic cold front is moving south and east across the gulf and stretches from the Yucatan into the Florida Panhandle. Cold high pressure is located from Northeast Mexico to Central Canada. Temperatures under the ridge are running 20 to 40 degrees below normal for the date. The sun has been peaking out, however all of the area remains below freezing and covered in a sheet of ice and snow including the beaches. Temperatures will climb to around the freezing mark.
/Issued 237 PM CST Mon Feb 15 2021/ Some low cloud and light snow/flurries persist underneath the upper trough this afternoon. This could last into the evening before the upper trough lifts northeast away from the region. Snow will begin to spread east into the region during the late afternoon as warm advection strengthens north of a sharpening 850mb warm front just south of the Red River.
Current temperatures are in the lower to mid teens, with northerly winds of 10 to 15 mph. Otherwise, have held highs at or below freezing for most of the area with the snow pack in place. This is unlikely, and puts the chance for more freezing rain into the equation instead as the rain aloft falls on the sub-freezing surface. Some warmer conditions are likely, but may take until the weekend to see it.
Current temperatures are in the lower to mid teens, with northerly winds of 10 to 15 mph. Otherwise, have held highs at or below freezing for most of the area with the snowpack in place.
Scattered light precipitation, especially for the higher elevations, will continue through Tuesday as a weak disturbance moves through the region.
229 PM PST Mon Feb 15 2021 Scattered light precipitation, especially for the higher elevations, will continue through Tuesday as a weak disturbance moves through the region.
Aside from stray showers Tuesday morning, high pressure will allow for a couple of dry days with some sunshine.
Despite temperatures remaining below freezing through the day, pockets of sunshine have allowed what frozen precip had stuck to paved surfaces to at least melt somewhat. An Arctic cold front is moving south and east across the gulf and stretches from the Yucatan into the Florida Panhandle. Cold high pressure is located from Northeast Mexico to Central Canada. Temperatures under the ridge are running 20 to 40 degrees below normal for the date. The sun has been peaking out, however all of the area remains below freezing and covered in a sheet of ice and snow including the beaches. Temperatures will climb to around the freezing mark.
The warm up has been very slow, however, as readings only reaching single digits to teens in most locations, with a little warmer air up off the surface with some 20s and 30s above 5000 feet. Model soundings don't have a great dendrite growth zone at the time of max lift (Tuesday morning) but may be over estimating the amount of warmer air near the surface. The higher terrain will see several inches of new accumulations, especially the west facing slopes.
As the lower atmosphere moistens, the light snow or snow showers are expected to reach the ground late tonight in the central zones, Tuesday morning over the SE zones. Remainder of the forecast period will see generally dry weather with a warming trend as an upper ridge builds over the west coast.
Much improved flight restrictions through this taf cycle as IFR gives way to MVFR and eventually VFR as drier high pressure builds into the region from the west. Winds will kick off slightly elevated in the 10-15kts range with 20-25kt gusts out of the west as the cold front advects through the region, however should weaken slightly and veer northwesterly through the late morning and afternoon hours as PGFs relax. CDG Chattanooga Airport, TN 32 22 48 38 50 / 10 0 20 100 90 Knoxville McGhee Tyson Airport, TN 31 21 45 35 47 / 10 0 10 100 90 Oak Ridge, TN 31 20 44 34 46 / 10 0 10 100 90 Tri Cities Airport, TN 34 20 47 34 49 / 20 0 10 90 90.
114 AM MST Tue Feb 16 2021 Overview: Deep troughing /cyclonic flow aloft/ will prevail over the CONUS throughout the short term period. as the MSLP gradient begins to tighten on the eastern periphery of a developing lee trough in Colorado.
Current temperatures are in the lower to mid teens, with northerly winds of 10 to 15 mph. Otherwise, have held highs at or below freezing for most of the area with the snow pack in place.
1226 AM CST Tue Feb 16 2021 Summary: Warmer temperatures expected with a return to normal by the weekend. The remainder of the week the jet stream will make a slow advance northward helping to bring warmer air to the north, but the Northland will still be 5 to 10 degrees below normal. High pressure remains in place across the Northland.
The arctic ridge will move east out across western and eventually central Kansas tonight. The return flow will only recirculate the arctic airmass (not a warming wind direction), and with an expected increase in stratus cloud cover by afternoon, we will likely not see afternoon temperatures much warmer than today, unfortunately. Wednesday will be more of the transition day, but the low 20s we have in the forecast will be a welcome return, as strange as that sounds.
Current temperature has already broken the record low for today and will shatter the low of 3 deg set in 1920 for Tuesday.
As the upper low tracks east to the north, colder air will filter into the region with the threat of freezing drizzle and light snow showers later through the coming day. With favorable wind direction, some lingering snow showers are likely for the first half of Tuesday night, especially in the ridges. High pressure associated with Arctic air will filter in tonight with temps dropping into the single digits for lows. Surface ridging will keep the region dry Wednesday as seasonably cool temperature persists.
Scattered snow showers will persist Wednesday, before warmer and drier weather arrives for the end of the week. A low-amplitude trough entering the Pacific Northwest will move southeast through the Great Basin tonight and into eastern Arizona tomorrow. Cooler air aloft, upslope flow and a cold frontal passage Tuesday will provide enough forcing for another round of rain and snow showers. The remainder of the week will feature dry and warmer weather, with a potential dry cold frontal passage over the weekend. A trough of low pressure will move from northwest to southeast across northern Arizona tonight and Tuesday.
Meanwhile, high pressure centered just to the west across IA/MN continues to slowly meander east. The slow upward trend in temps begins today with 925 mb temps moderating appreciably from yesterday into the -13 to -18C range through the day, warmer east of the MS River. While another night of subzero temps is likely tonight as the ridge axis passes overhead, don't expect the temps/wind chills to be as low thanks to continued gradual warm advection, some increase in clouds and light winds.
Temperatures will be slightly warmer on Tuesday, however another cold front will move southward through the region on Wednesday, bringing back some cooler air and light snow. After slight warmer temperatures on Tuesday, a cold front will move southward through the region on Wednesday, bringing down some colder air for one day, along with light snow.
However, cold temps will linger overnight and not get above freezing during the day Tuesday as highs will only be in the upper teens to low 20s.
A broad region of generally light to locally moderate snowfall is wrapping around a mid-level low pressure cell lifting northeastward along the Kansas Turnpike This low continues to lift into Missouri tonight and should result in a rapid end to the snowfall this evening. Did extend the winter weather advisory through 6 pm given the potential impacts on any evening commuters, but the dearth of moisture, plate ice crystal structure, and lack of aggregation is keeping snow ratios on the lower side. While winds lessen with the approaching ridge, temperatures overnight are progged to plummet once skies clear. Weak isentropic ascent ahead of the H700 trough could fuel another round of light snow Tuesday night into Wednesday morning, with the highest probabilities along and southeast of the Turnpike.
Look for precipitation to spread into Middle Tennessee on Wednesday, with some accumulation of snow and ice possible Wednesday night as temperatures drop below freezing.
A lull under brief ridging is expected late week. Meanwhile as the flow has veered across northern Utah and cooler 500mb temps have pushed south steepening lapse rates across the area, precipitation has trended more convective with a fairly persistent band stretching across northwest Utah into the Ogden/Brigham City area. The passage of the upstream mid level trough should help push this band south through Davis and Salt Lake counties overnight, which is what the last few HRRR runs have suggested.
A weak upper level trough embedded in northwest flow aloft is crossing our forecast area this evening, with scattered rain showers at lower elevations and snow over the higher terrain. This will help keep snow going, especially in the higher terrain.
Tuesday night we see an increase in clouds as mid /high-level moisture increases ahead of a weak trough approaching from the west. Warmer temperatures will occur, it is just the magnitude of the warmth early in the forecast as models still remain slightly cooler than a few days ago on highs/lows.
For overnight, another line of showers and storms will move through all our forecast area ahead of a cold front. Temps will reflect the passage of a cold front as highs are expected to only reach the 70s. Otherwise, south winds will range 15 to 25 kt tonight and shift from the west with the cold front passage and shift from the northwest Tue afternoon.
West of I-25 will see lows in the lower teens with wind chills in the lower single digits dipping into the negatives.
928 AM EST Tue Feb 16 2021 High pressure and drier air will build over the region today in the wake of the departing low pressure system.
/issued Issued by National Weather Service San Juan PR/ SHORT TERM (Today through Wednesday): Sub-freezing temperatures are currently being reported across most of Deep South Texas, with readings in the lower to middle 20s due to the combination of generally clear skies and very light winds. High pressure is expected to remain in control through at least this afternoon with dry conditions expected. This will allow high temperatures to climb even higher than today, possibly into the lower to middle 60s.
Cold front has been a little slower than forecast but still several more degrees of cooling this morning to go before bottoming around noon out 3 to 6 degrees cooler than 6 AM temps. Loaded latest hires guidance for temps and seeing max temps a degree or two cooler than what was sent at 3 AM. QPF for the event has trended down a little as sfc warm front not quite as far north as previous guidance. Main threat for any strong/severe storms should be over middle GA between 3am and 3pm Thurs based on latest timing of pre-frontal trough.
We could see a few flurries tonight with some clouds and a passing upper trough, but nothing to worry about.
This could bring a shot of slightly cooler air, dropping lows back below zero for Wednesday night, and some snow to central Montana. Remainder of the forecast period will see generally dry weather with a warming trend as an upper ridge builds over the west coast.
Temperatures this afternoon are expected to recover into the mid to upper 20s for highs across the Big Country, and into the lower 30s across the southern half of our area. With the approach of this trough, an area of light snow is expected to overspread much of the Big Country this afternoon. The most likely precipitation is expected to be freezing rain in our southeastern counties, mainly after Midnight. Even without additional precipitation, limited melting today followed by re-freezing tonight will continue the concern for ice on roads.
A broken line of showers and isolated lightning storms along the leading edge of a cold front have made it to just south of Ft. Behind the front cooler, drier air has filtered in as most locations actually saw a drop in temperatures after sunrise.
257 AM PST Tue Feb 16 2021 Locally breezy north winds today will diminish a bit Wednesday as low pressure shifts slowly east out of the area.
335 AM PST Tue Feb 16 2021 Spotty light precipitation over the higher elevations will continue this morning as a weak disturbance moves out later in the day.
With favorable wind direction, some lingering snow showers are likely for the first half of Tuesday night, especially in the ridges. High pressure associated with Arctic air will filter in tonight with temps dropping into the single digits for lows.
Larger scale upper trough remains in place across the central US, and arctic high pressure is lingering over our northern MN. Temperatures tonight should be a bit warmer due to increased mixing and less clouds but many locations should still fall below zero and some parts of MN may still be close to 20 below zero. Temperatures could reach freezing by the time we start the work week. GEFS continues to be bullish with snow amounts, so confidence is on the lower end of the spectrum with regards to that.
440 AM EST Tue Feb 16 2021 Flurries will occur today in the cold air behind departing low pressure.
QPF for the event has trended down a little as sfc warm front not quite as far north as previous guidance. Main threat for any strong/severe storms should be over middle GA between 3am and 3pm Thurs based on latest timing of pre-frontal trough.
The quiet weather pattern will continue through the remainder of the week as strong high pressure and steep ridging remains across the western and central US.
439 AM CST Tue Feb 16 2021 Many locations in our western CWA will finally see temperatures warm above freezing this afternoon as westerly downslope winds kick in. If we fail to reach freezing in Midland today, it would be our 6th day in a row with a high temperature below freezing which is a new record. A cold front will arrive on the heels of the departing upper trof early Wednesday with Arctic air filtering back into the CWA.
An upper level short wave trough just taking shape over the 4-corners region and supported by 150+ kt jet streak nosing southeastward out of northern California and Nevada will sharpen as it moves southeastward, progged to cross the South Plains/Panhandle region tonight. Earlier indications suggest a potential for some freezing rain as precipitation begins. Focus for snow then shifts pretty quickly northward this evening as the upper trough moves across northeastern New Mexico and the dynamics focus across the Panhandle.
An additional weak disturbance will produce a few afternoon snow flurries on Wednesday, before warmer and drier weather arrives for the end of the week. The main focus of this system will continue to be over the Chuska Mountains, Black Mesa and the White Mountains areas with 3 to 6 inches of snow possible (higher amounts in locations such as Buffalo Pass and the highest peaks in the White Mountains where 8 to 10 inches could accumulate).
358 AM MST Tue Feb 16 2021 A short wave trough in the northwest flow aloft will move across Colorado today and this evening. Lift from the trough, orographic lift, and weak instability will help produce snow over the mountains today and tonight. Snowfall amounts across the lower elevations are expected to be light and less than an inch. The air just above the inversion in the lower foothills is in the lower 30s at this time. In addition, shallow upslope following the passage of a cold front that will back its way into the Front Range late Wednesday afternoon.
Some improvement, to MVFR, will be likely at the NE OK terminals in the last few hours of the valid TAF period as the higher intensity snows shift to the south and east.
Western parts of southeastern MO may get into the lower 20s as a result, but the majority of our region is in for another frigid day in the teens with plenty of snow cover in place, but with a gradually subsiding wind. However, for about a 12 hour period (06Z- 18Z Wed), most of southeastern MO has the potential to receive a quick 2+ inches of snowfall, especially west, and in the higher elevations. Pcpn type is expected to be mostly snow, but late Wed night/early Thu drier air aloft may interfere with the ice nucleation process and cause periods of freezing rain to occur for a time.
427 AM EST Tue Feb 16 2021 Quieter weather in store today relative to the past few days as a cold front moves south of area later this morning with northwest winds in its wake bringing cooler, less humid conditions after the remaining showers over central/southern areas move out. Lows tonight will be noticeably cooler, ranging from the low/mid 40s over the Nature Coast to the upper 50s/low 60s south. The boundary lifts back north across the peninsula as a warm front on Wednesday, hastily ending our reprieve as southerly flow advects warmth and moisture back over the area with above normal temps and highs once again in the 70s/80s on Wed/Thu with a chance of showers and an isolated thunderstorm.
Expect the low cloud cover to persist into early this afternoon, before ceilings climb above 3000 ft. For tonight, our southern terminals could be affected by patchy fog and light freezing rain.
338 AM MST Tue Feb 16 2021 Some banding set up over southeast Utah into southwest Colorado last night into early this morning, resulting in a quick couple inches of snow along the Highway 491 and 160 corridor. This enhanced forcing is a result of an upper level trough passing through with the strongest forcing passing through the Four Corners as a modest QG forcing bullseye tracks near or just southwest of the Four Corners.
The upper-level pattern will shift from a NW flow to a W flow as the Tri-State area sits at the bottom of a trough extending from southern Quebec into the Plains. A weak upper-level trough will continue to move across the Intermountain West throughout the day, prompting the shift in flow aloft. Models seem fairly confident in a trough strengthening along the Rockies from Montana to New Mexico. Temperatures today are expected to warm, with the higher temperatures expected in eastern Colorado and cooler temperatures over the eastern half of the area. After sunrise, wind chill values are expected to gradually decrease and become warmer than warning criteria around mid-day. The upper-level trough will begin to move across the High Plains during the evening hours and continue to slowly shift east overnight as it deepens into central New Mexico and west-central Texas.
A deep full-latitudinal long wave trough extending from the Upper Great Plains southward into the extreme Southeast Gulf of Mexico early this morning will lift northeastward, resulting in most of the mid and upper level ascent remaining well north of our area.
700 AM EST Tue Feb 16 2021 Flurries will occur today in the cold air behind departing low pressure.
The Northern Rockies will remain under moist, northwest flow through Wednesday evening as Pacific moisture rides over a ridge of high pressure situated over the eastern Pacific Ocean.
For tonight, we'll see mid-upper clouds start to increase this evening as low level warm advection begins ahead of a weak trough approaching from the west.
SHORT TERM (Today through Wednesday): Sub-freezing temperatures are currently being reported across most of Deep South Texas, with readings in the lower to middle 20s due to the combination of generally clear skies and very light winds. High pressure is expected to remain in control through at least this afternoon with dry conditions expected. This will allow high temperatures to climb even higher than today, possibly into the lower to middle 60s.
519 AM MST Tue Feb 16 2021 Some banding set up over southeast Utah into southwest Colorado last night into early this morning, resulting in a quick couple inches of snow along the Highway 491 and 160 corridor. This enhanced forcing is a result of an upper level trough passing through with the strongest forcing passing through the Four Corners as a modest QG forcing bullseye tracks near or just southwest of the Four Corners.
249 PM EST Tue Feb 16 2021 High pressure and drier air will build over the region today in the wake of the departing low pressure system.
232 PM CST Tue Feb 16 2021 Summary: Getting warmer, but still cold enough for wind chill advisories before a little snow arrives.
An additional weak disturbance will produce a few afternoon snow flurries on Wednesday, before warmer and drier weather arrives for the end of the week. Expect a quick half inch to inch of snow from this band as it moves south, with the higher amounts on the east side. The main focus of this system will continue to be over the Chuska Mountains, Black Mesa and the White Mountains areas with 3 to 6 inches of snow possible (higher amounts in locations such as Buffalo Pass and the highest peaks in the White Mountains where 8 to 10 inches could accumulate).