Aikyam-Lab/Synoptic-Bench huggingface dataset:
328 PM EST Wed Dec 30 2020 Strong southerly flow has continued this afternoon, ahead of a cold front pushing its way across the Ohio river valley this afternoon. Temperatures have warmed into the lower 60s in most areas. The main focus for the short term is around the cold front as it pushes into and across the area tonight. The cold front will stall out along the VA/KY state line on Thursday, with low clouds hanging on north of the boundary through the day. By Thursday night, we will be watching s developing low pressure system take shape across the plains with the stalled frontal boundary eventually lifting back to the north as a warm front.
204 PM EST Wed Dec 30 2020 Upper ridging near Cuba extends northward over the Bahamas and along the eastern seaboard.
Short term guidance generally decreases midlevel frontogenesis over the next couple of hours so rates should decrease, and thus more rain rather than snow, especially as precipitation generally moves southeastward where temperatures are warmer.
Areas closest to the ridge axis from Highway 25 and west are seeing decreasing northwest flow, while locales east are still seeing northwest flow, but gusts 15-20 mph at times. Models show blocking upper ridges on the west coast and over the eastern third of the country. This ridge in combination with the blocking upper support, will keep the surface system over the southern Plains.
20z WV satellite shows a longwave upper trough extending from Wisconsin southwest to an upper low over Sonora.
Latest surface analysis places a cold front just north and of the I-40 corridor, demarcated by a line of heavier rainfall on radar. Temperatures will fall into the low to mid 30s across the far northern portions of the CWA by daybreak. There is the potential for a brief mix of sleet across extreme northwest portions of the forecast area, but temperatures at the surface will remain above freezing negating any impacts. Meanwhile, a potent upper level low will dig through northern Mexico tomorrow morning, with cyclogenesis occurring over south Texas.
Northern track = likely more snow, but also some threat for freezing pcpn. Model guidance suggests this tries to erode toward morning as a high pressure ridge works into the area, but this may be too fast given the time of year and trends will have to be monitored for possible adjustments. If low clouds do scatter out late tonight, there would be the potential for patchy fog developing in light winds underneath the ridge axis. Northwest winds should become light and turn more westerly overnight, becoming southerly by Thursday morning as high pressure moves east.
506 PM MST Wed Dec 30 2020 Upper trough extended from the western Great Lakes to the south central High Plains and a upper ridge reached from CA into ID. The passage of a weak trough late Thursday will enhance orographic flow for light snow over the southern WY mountains.
Didn't really make too many changes to tonight's lows with temps in the low teens to single digits expected over the plains.
A narrow swath of 1 to 2 inch snowfall occurred earlier with this band, however with temperatures above freezing most roadways will likely be clear shortly after the snow passes. The heavier rainfall will begin develop across far southeast Oklahoma late tonight into Thursday morning as the strong upper low approaches from the southwest.
323 PM CST Wed Dec 30 2020 High pressure over the mid-Missouri River Valley will drift east in the lower Great Lakes through Thursday.
Model soundings suggest that precipitation should fall as snow, unless surface temperatures are sufficiently above freezing for a change over to rain. Upper level low over the Great Lakes continues to push eastward with northwest flow in place over the Northern Plains. As this ridge continues to move eastward, low level stratus was eroding slightly with the back edge just about to Bismarck by mid afternoon. Thursday highs expected to range from the low 40s southwest to the mid 20s northeast.
A cold frontal passage tonight into Thursday morning will bring some light showers to mainly the Sierra from Yosemite to Kings Canyon.
The cold front is slowly inching its way across Middle Tennessee this evening. Have adjusted temperatures to account for the slow frontal passage with temperatures still in the low 60s in the southern most counties. Rainfall rates are light in the precip that is currently streaming across the western half of the area, but a few pockets of moderate rain could develop as we go through the night, with our northwestern counties seeing the highest amounts of rain overnight. Cold front has passed CKV and will move through BNA/MQY by 01-02Z, but stall and not reach CSV until late Thursday morning.
Latest surface analysis places a cold front just north and of the I-40 corridor, demarcated by a line of heavier rainfall on radar. Temperatures will fall into the low to mid 30s across the far northern portions of the CWA by daybreak. There is the potential for a brief mix of sleet across extreme north and western portions of the area, but temperatures at the surface will remain above freezing negating any impacts. Meanwhile, a potent upper level low will dig through northern Mexico tomorrow morning, with cyclogenesis occurring over south Texas.
This snow will help keep temps low overnight as high pressure settles in. The low sun angle will be no match for the snow's high albedo. As the low closes tonight, it will take a sharp turn north, following the jet's path around a Caribbean high.
A high pressure to our northeast will keep a southeast wind flow tonight, bringing in a few light showers to the coastal waters but barely making it to the coast. Low temps are forecast to only drop to the upper 60s across the coastal counties but will cool down to the lower 60s across the interior. A nice weather day is forecast to end the year as temps climb to the lower 80s with a nice breeze from the southeast and no precipitation expected over land. As a high pressure to our northeast moves further east towards the central Atlantic, winds over our local waters will remain from the southeast.
Beyond that dry weather will be the rule with a shot of cooler and drier area to start the new year with a gradual warming trend through mid week.
Given the favorable conditions and fresh snow pack, low temperatures have been dropped to the lower end of guidance with single digits possible for much of the area east of the Missouri River. Light breezes and mostly sunny skies are expected for the rest of the area, as a warm front lifts northeast through the day.
Steady rain will overspread the region through tonight ahead of a cold front that will force a change over to light snow Thursday morning. Another storm system will move in quickly early New Year's Day, bringing some freezing rain in the early morning, before becoming widespread rain during the day as temperatures warm quickly above freezing. Light to moderate widespread rain forced by decaying frontogenesis will move in this afternoon as a cold front approaches from the northwest.
232 PM MST Wed Dec 30 2020 Upper trough extended from the western Great Lakes to the south central High Plains and a upper ridge reached from CA into ID. The passage of a weak trough late Thursday will enhance orographic flow for light snow over the southern WY mountains.
406 PM MST Wed Dec 30 2020 WV imagery this aftn depicts an upper low near the Pac NW coast and another in nrn MX. At the sfc, weak ridging is giving way to pressure falls as troughing develops in the lee of the Rockies.
208 PM MST Wed Dec 30 2020 The northern branch of the upper flow progresses east of the region with an upper short wave ridge moving over the forecast area tonight. As the northern branch continues east, the low at the base of the upper trough cuts off over northern Mexico and become less progressive until a kicker drops south through California on Thursday.
convection becomes widespread late, primarily in the form of a squall line associated with an approaching pre-frontal trof. Beyond that dry weather will be the rule with a shot of cooler and drier area to start the new year with a gradual warming trend through mid week.
227 PM MST Wed Dec 30 2020 WV imagery this aftn depicts an upper low near the Pac NW coast and another in nrn MX. At the sfc, weak ridging is giving way to pressure falls as troughing develops in the lee of the Rockies.
Winds will start to decrease as a trough axis cross the area and disrupts the pressure gradient. Temperatures overnight will stay a little warmer thanks to some mixing from the stronger winds, with lows in the upper 20s for most of the area. This trough will also bring a chance of snow to parts of the area. Mostly expecting the snow to be in the higher terrain. Temperatures tomorrow afternoon should be getting into the lower 40s. Precipitation will mostly be confined to the mountains in the form of light snow as downsloping flow will cause much of the precipitation over the mountains to evaporate before reaching the ground over the lower elevations.
353 PM MST Wed Dec 30 2020 The northern branch of the upper flow progresses east of the region with an upper short wave ridge moving over the forecast area tonight. As the northern branch continues east, the low at the base of the upper trough cuts off over northern Mexico and become less progressive until a kicker drops south through California on Thursday.
Previous model runs hinted at some snow flurries/light freezing drizzle later tonight, but fog now appears to be the main hazard that could bring MVFR to IFR ceilings and visibilities later tonight into Thursday morning due to low-level warm air advection developing. A brief period of gale-force winds is possible this evening along portions of the North Shore due to strong katabatic downsloping northwesterly winds behind a departing low-pressure system. Elsewhere, blustery northwesterly winds will continue this evening with gusts up to 25 knots will continue this evening along parts of the South Shore before decreasing in speed later tonight as high pressure passes by to the south.
526 PM CST Wed Dec 30 2020 High pressure over the mid-Missouri River Valley will drift east in the lower Great Lakes through Thursday.
844 PM CST Wed Dec 30 2020 High pressure over the mid-Missouri River Valley will drift east in the lower Great Lakes through Thursday.
As an upper level low over TX starts to lift north in our direction, MVFR cigs and rain will begin to spread back north over the region during the day on Thursday. A narrow swath of 1 to 2 inch snowfall occurred earlier with this band, however with temperatures above freezing most roadways will likely be clear shortly after the snow passes. The heavier rainfall will begin develop across far southeast Oklahoma late tonight into Thursday morning as the strong upper low approaches from the southwest.
704 PM EST Wed Dec 30 2020 Upper air pattern consists of a 500 mb trough over the upper Great Lakes this morning which will head east and be exiting the area by this evening. trough will kick out the closed low over northern Mexico to the northeast into TX on Thu. Thursday night high pressure settles in over the Lower Great Lakes, resulting in an uneventful partly cloudy to clear evening for the region.
148 AM MST Thu Dec 31 2020 08z surface analysis had low over north central MT with warm front into western NE.
Previous model runs hinted at some snow flurries/light freezing drizzle later tonight, but fog now appears to be the main hazard that could bring MVFR to IFR ceilings and visibilities later tonight into Thursday morning due to low-level warm air advection developing. High pressure will work into the region tonight with winds slowly becoming southwesterly at 5 to 15 knots with a few gusts to around 20 knots along the Bayfield Peninsula. As the ridge axis moves east of the region Thursday, southwesterly winds will increase to 10 to 15 knots with gusts to 25 knots along the North Shore, mainly from Grand Marais to Grand Portage.
For today, a ridge of high pressure will drift across the area, setting up a light southerly wind flow by afternoon. Mixing in the lower layers should be enough to disperse stratus clouds with hopefully mostly sunny skies expected by afternoon. Quiet conditions tonight with a gradual increase in cloud cover ahead of low pressure moving northeast out of the Southern Plains.
104 AM EST Thu Dec 31 2020 Expect rain changing to snow tonight into Thursday as a cold front moves southeast.
939 PM MST Wed Dec 30 2020 The northern branch of the upper flow progresses east of the region with an upper short wave ridge moving over the forecast area tonight. As the northern branch continues east, the low at the base of the upper trough cuts off over northern Mexico and become less progressive until a kicker drops south through California on Thursday.
313 AM EST Thu Dec 31 2020 Deep return southeast flow from the surface to 50H is anchored over the Florida peninsula as the region is wedged between strong high pressure over the western Atlantic and a developing low pressure system over eastern Texas.
Flow becomes more zonal as the trough to our east pulls further away.
Upper level low moving onshore which will bring the next band of snow through the area tonight into early Thursday. Latest high-res models remain on the lower end of snowfall along with the NBM ensemble. Another round of snow showers is expected Thursday afternoon which could bring a dusting in the lower valleys to around an inch in the mountains.
An area of high pressure at the surface will slide east across the Central Plains and by daybreak the center of this high will extend from Missouri to central Oklahoma as a trough of low pressure at the surface begins to develop over eastern Colorado. An upper low, located over northern Mexico at 18z Wednesday, will be slowly moving towards southwest Texas. The upper low will deepen during the day on Thursday as it slowly moves east across south Texas.
Parts of northwest and northern AR will continue to see a mix of rain and wintry precipitation through Thursday morning, turning to all liquid by the afternoon as temperatures warm above freezing.
1151 PM EST Wed Dec 30 2020 Upper air pattern consists of a 500 mb trough over the upper Great Lakes this morning which will head east and be exiting the area by this evening. trough will kick out the closed low over northern Mexico to the northeast into TX on Thu. Thursday night high pressure settles in over the Lower Great Lakes, resulting in an uneventful partly cloudy to clear evening for the region.
This cold front will stall and retreat northward on Thursday as deep southerly flow increases ahead of a dynamic upper trough. Made minor adjustments to hourly grids and increased temperatures a couple degrees across northern zones due to cloud cover and winds keeping temperatures a few degrees warmer than forecast. Proximity of surface cold front, which will likely be aligned with the I-75/I-81 corridor by midday or early afternoon, would give confidence in continued MVFR conditions through the day. CD Chattanooga Airport, TN 60 54 68 47 60 / 40 90 90 10 20 Knoxville McGhee Tyson Airport, TN 58 50 66 49 59 / 30 70 80 20 20 Oak Ridge, TN 56 49 66 47 57 / 30 80 80 10 20 Tri Cities Airport, TN 56 47 59 47 58 / 20 60 80 30 20.
The cold front is slowly inching its way across Middle Tennessee this evening. Have adjusted temperatures to account for the slow frontal passage with temperatures still in the low 60s in the southern most counties. Rainfall rates are light in the precip that is currently streaming across the western half of the area, but a few pockets of moderate rain could develop as we go through the night, with our northwestern counties seeing the highest amounts of rain overnight. Cold front is now southeast of CKV/BNA/MQY and looks to reach CSV in a few hours.
357 AM EST Thu Dec 31 2020 Rain showers will change to snow showers overnight as colder air moves in behind a cold front.
An upper low over TX will lift north into the region, causing the spread of rain and lower cigs (MVFR then IFR) across the region from south to north tomorrow into tomorrow night. Also added mention of FZRA at KBVO where sfc temps will drop to near freezing toward the end of the forecast. was filtering into Eastern Oklahoma and far Northwest Arkansas behind the cold front that pushed through the region last night/this morning. A few radar echoes remained on the northern edge of the deeper moisture within the higher terrain locations of far Northwest Arkansas which could be in the form of a light rain/freezing rain. rain/freezing rain. potential within the higher terrain of Southern Le Flore co if surface temps can cool enough. tonight looks to be a somewhat lull in overall precip chances before the upper level low.
1045 PM MST Wed Dec 30 2020 Upper trough extended from the western Great Lakes to the south central High Plains and a upper ridge reached from CA into ID. The passage of a weak trough late Thursday will enhance orographic flow for light snow over the southern WY mountains.
was filtering into Eastern Oklahoma and far Northwest Arkansas behind the cold front that pushed through the region last night/this morning. A few radar echoes remained on the northern edge of the deeper moisture within the higher terrain locations of far Northwest Arkansas which could be in the form of a light rain/freezing rain. rain/freezing rain. potential within the higher terrain of Southern Le Flore co if surface temps can cool enough. tonight looks to be a somewhat lull in overall precip chances before the upper level low.
Winds remain light across the region, with temperatures in the lower teens.
The upper level trough moving across the Great Basin will weaken as it arrives over western Utah Thursday.
Complicated scenario setting up across the region this morning as a dirty ridge passes overhead. Improvement to VFR is expected by late morning as the low levels mix out. High pressure will work into the region tonight with winds slowly becoming southwesterly at 5 to 15 knots with a few gusts to around 20 knots along the Bayfield Peninsula. As the ridge axis moves east of the region Thursday, southwesterly winds will increase to 10 to 15 knots with gusts to 25 knots along the North Shore, mainly from Grand Marais to Grand Portage.
1236 AM EST Thu Dec 31 2020 Rain showers will change to snow showers overnight as colder air moves in behind a cold front.
1120 PM CST Wed Dec 30 2020 High pressure over the mid-Missouri River Valley will drift east in the lower Great Lakes through Thursday.
1004 PM MST Wed Dec 30 2020 WV imagery this aftn depicts an upper low near the Pac NW coast and another in nrn MX. At the sfc, weak ridging is giving way to pressure falls as troughing develops in the lee of the Rockies.
Mild and breezy conditions continue today as an upper disturbance moves across the region, with light snow ending by afternoon over the higher elevations of southwest Montana, while continuing toward Marias Pass. Upper ridging moves over the area overnight tonight and then flattens Friday with westerly flow increasing, resulting in another breezy and mild day with increasing cloud cover through the day as the next system approaches from the west. A pair of strong and fast-moving disturbances with jet stream energy will move across the region both days in the wake of the high pressure ridge, both resulting in periods of mountain precipitation and potentially strong downsloping winds over the plains.
Very complicated forecast tonight into Friday as strong area of low pressure is expected to move from central and eastern Texas towards southern Missouri. 00Z Models have trended farther south and east with this system, shifting the warmer air aloft south and east and thus adjusting the icing potential accordingly. As upper low moves into the Southern Plains this evening, expect precipitation shield to expand north. May see surface temperatures fall a few degrees as upper trough moves in and the precipitation begins. However, with deep (~8-10K feet) isothermal layer right at freezing, small changes in trajectory could have large changes in precipitation type. Precipitation is expected to wind down across the area Friday afternoon as low pressure system lifts towards the Great Lakes region.
As the ridge axis centers over central UP this aftn, skies should be clear, leading to a beautiful UP day for much of the western interior. SW winds will start to bring some light downsloping winds into Marquette proper, which will likely make them a couple degrees warmer than up the hill in the highlands. Tonight, the slightest of ridges begins to move overhead as weak WAA will likely bring in some cloud cover as the night goes on. Sat-Sun, mid level ridging over the area with sunshine during the afternoon will boost temps into the low to mid 30s. Tue-Wed, Mid level and sfc ridging is expected to give way to increasing WAA and low level moisture as a trough approaches from the Plains.
/issued 312 AM CST Thu Dec 31 2020/ The upper level low was churning across Durango early this morning but is still expected to undergo a sharp turn to the northeast later this morning. Moisture and lift will wrap around the system into the Rolling Plains as the center of the low moves through central Texas. A secondary 500 mb closed low will rotate into the Big Bend region by Friday afternoon as a belt of potent meridional flow digs in over central Mexico.
The cold front has stalled south and southeast of the state. An additional 1 to 2 inches of rainfall is forecast through late Thurs, with the highest amounts expected over southern and western AR. A winter weather advisory has been issued for those areas late Thursday evening and into the overnight hours, when temperatures will be near and just below freezing. Temperatures will begin increasing over southern AR overnight, and over the rest of the state by Friday morning, as the system brings warmer air into the region. Above freezing temperatures are expected by morning, allowing precipitation to transition to all liquid rain. Wind direction will shift from NNEerly Thursday to Serly by Fri morning as the low moves through the state to the NE.
Temperatures tonight are expected to gradually fall into the low to mid 30s across all of the Ozarks. For locations that drop below freezing, some freezing rain accumulations are likely. We have the most confidence that areas from west central Missouri to central Missouri will experience temperatures below freezing, and could accumulate ice amounts ranging from a glaze to two tenths of an inch. As the upper low shifts to the northeast on Friday morning, some light snow will be possible.
The evolution of the splitting trough remains the same. The end result? Some snow for the eastern Uintas through the day and maybe some flakes at the higher elevations of the San Juans Friday morning as wind flow may allow orographics to squeeze out a bit of moisture. Friday brings another transitory ridge to our CWA as the next system edges into the PacNW. The New Year's closed low will continue to lift into the Southern Plains Friday night, leaving the region under northwest flow.
Freezing fog leading to reduced visibility and isolated slick roadways will be a concern on Friday morning for valley locations that experience partial clearing.
A closed upper low over northern Mexico will take a sharp left turn northward over Texas today, while a ridge holds firm over the Bahamas. With the trough quite far to our west, 500 mb flow over our area will have a slight anticyclonic curvature. As the upper low moves from Texas into Oklahoma, deep-layer southerly flow will strengthen across Alabama tonight. Isentropic lift will accompany the northward advancement of a warm front, with rain becoming widespread. Somewhat better organization may occur later Friday morning over our southeastern counties as a moisture and instability gradient becomes better defined along the cold front, but low-level directional shear may become less favorable with time.