Aikyam-Lab/Synoptic-Bench huggingface dataset:
330 AM MST Mon Dec 12 2022 Synoptic Setup: Current setup begins with a huge trough moving across the Four Corners and an Arctic airmass dropping down the Front Range through Montana. Farther west a highly amplified ridge is developing of the north american coast from the Gulf of Alaska to southern California. Prior to the snow setting in we are also expecting morning freezing fog and low stratus to be a menace to general visibility and aviation till the snow begins. Meanwhile, the base of the trough will form a Colorado Low and take it northeast across the Plains where Gulf Moisture will begin to wrap up and slowly get pulled into the northwest quadrant of the Low.
Very cold temperatures follow the front, with daytime highs lingering near freezing for the High Country Monday and Tuesday.
A deep trough with a strong low will push through the Great Basin today.
Moisture is wrapping into north-central Idaho and western Montana, around a low pressure circulation that has developed in southern Idaho. Snow showers associated with the low have been moderate at times and will continue to move through the region today.
415 AM MST Mon Dec 12 2022 Water vapor imagery shows two upper lows in the overall longwave trough. A cold front will push across the region today. Tonight and Tuesday, the forcing will transition to more upslope flow, and wrap around moisture from this slow moving upper low.
613 AM EST Mon Dec 12 2022 Dry and cool today under the influence of high pressure. High pressure Tuesday.
933 AM EST Mon Dec 12 2022 Dry and cool today under the influence of high pressure through Tuesday.
Dry and cool weather is on tap this week with high pressure and offshore flow.
Changes begin to take shape tonight into Monday as sfc ridging shifts east of the area and mid-level flow becomes swrly ahead of a deepening cyclone over the Central Plains.
557 AM EST Mon Dec 12 2022 High pressure will control our weather today and tonight.
Forecast Discussion: Early this morning, water vapor imagery shows two cyclonic circulations over the western CONUS within a highly amplified troughing pattern. An upper level ridge is noted over the central US with another trough over far eastern Canada and the northeastern US. Ascent will continue to increase over the region this evening and tonight with the approach of the western trough. The upper low will then become nearly stationary just north of the area through midweek before progressing toward the Great Lakes region late in the week.
Quieter and much colder weather with lighter winds will prevail this week with areas of freezing fog.
657 AM EST Mon Dec 12 2022 (Today through Tuesday) Latest model data and sfc analyses show a dissipating boundary still lingering over northern Florida, while high pressure over the east GOMEX extends across SoFlo and into the west Atlantic. There are little to no consequences associated with the boundary as ridging remains strong across the area during the short term.
The strong low pressure system responsible for yesterday's widespread precip across the region will continue to move east across the western CONUS. While snow levels are much lower with the low center overtop the region, moisture is far less to come by so no additional significant impacts are expected other than some minor amounts. What was an eyebrow raising Pacific wave break situation spawning a closed low off the coast of southern California is now a much more progressive.
Present surface analysis has the forecast area situated under the regime of high pressure that's centered well to the north of the area. High pressure will remain in place through the day today and into tomorrow. Temperatures rebound and warm up for Tuesday as southwesterly flow and WAA takes over ahead of a longwave trough digging on the lee of the Rockies. The period will start with a very deep, stacked low pressure system centered over Nebraska, embedded in a large upper level trough. Flow off the gulf ahead of the front will rise isentropically, and with the support of the advancing trough, produce a large area of rain and showers.
The setup has allowed for widespread low stratus to thicken and spread from the Gulf Coast to the Tennessee Valley and the Carolinas to the High Plains of western Kansas. A deep low pressure system developing over the Central High Plains today will gradually turn winds out of the southeast by tonight, and increase warm air advection heading into tomorrow. /NF/ By Tuesday, a potent closed low system will move across the High Plains into the upper MS valley, bringing the potential for impactful severe weather across the Ozarks, Southern Plains, and Lower MS valley regions.
Temperatures early this morning are cooler than previously expected across much of central NV as skies have scattered out. An upper level low currently centered over NE Nevada will continue to bring snow to most of northern and portions of central NV today. As the upper level low drifts southeastward into Utah later this morning, snow showers will develop or intensify across most of Humboldt County, Northern Lander and Eureka Counties, along with most of Elko County. Guidance often does not handle QPF amounts very well when upper level lows bring wrap- around showers into northern NV, especially for N-NW facing slopes (such as the Lamoille and Spring Creek areas along the Ruby mountains). As the upper level low continues to exit to the SE, snow showers will diminish tonight, and taper off completely by Tuesday afternoon.
Temperatures will be warmer today as southerly low level flow ramps up. Meanwhile, water vapor imagery shows a potent upper level low spinning over the Great Basin. The low will move eastward across the southern Rockies tonight and into the Central Plains by Tuesday morning.
The Medford forecast area is under the back side of a deep long wave trough. Short waves diving down the trough are supporting light shower activity over the area. The showers will gradually diminish into Monday night, when the trough will move out to the east, taking the diving short waves with it. An offshore ridge will then approach the west coast. This will not be a strong ridge initially, but the upstream trough will shear and leave a cutoff low well offshore. The ridge behind that will build in strongly off the west coast around the middle of the coming week.
The large upper low is over southwest ID and will gradually travel to the south-southeast this afternoon. The low will be over NV/UT tonight, leaving the forecast area under a dry NNE flow aloft. Patchy freezing fog is forecast, but there is some uncertainty on whether dense freezing fog will return.
Weak surface ridging across the region will continue to shift eastwards, followed by another area of high pressure building into the area.
An upper level low currently centered over NE Nevada will continue to bring snow to most of northern and portions of central NV today. As the upper level low drifts southeastward into Utah later this morning, snow showers will develop or intensify across most of Humboldt County, Northern Lander and Eureka Counties, along with most of Elko County. Guidance often does not handle QPF amounts very well when upper level lows bring wrap- around showers into northern NV, especially for N-NW facing slopes (such as the Lamoille and Spring Creek areas along the Ruby mountains). As the upper level low continues to exit to the SE, snow showers will diminish tonight, and taper off completely by Tuesday afternoon.
926 AM EST Mon Dec 12 2022 High pressure will control our weather today and tonight.
Forecast Discussion: Early this morning, water vapor imagery shows two cyclonic circulations over the western CONUS within a highly amplified troughing pattern. An upper level ridge is noted over the central US with another trough over far eastern Canada and the northeastern US. Ascent will continue to increase over the region this evening and tonight with the approach of the western trough. The upper low will then become nearly stationary just north of the area through midweek before pivoting toward the Great Lakes region late in the week.
NorCal will be on the backside of the trough today as it moves to the south and east through the southwest. Cloud cover will clear from north to south today as upper level ridging builds. This will bring dry conditions through most of the week with cold overnight temperatures (around, or slightly below, the freezing mark in the Central Valley, and single digits and teens in the mountains).
237 PM CST Mon Dec 12 2022 A large and potent mid/upper trough over the Central Great Basin area today is progged to move into the Central Rockies tonight before emerging over the Northern Plains on Tuesday. A 130 knot upper level jet will round the base of this trough while nosing into the Central Plains this evening. Breezy but mild conditions are anticipated with above average highs topping out in the low 60s in southeast KS while some increasing clouds/low level cold air advection keep highs from reaching 50 over our central KS counties. The slow moving mid/upper trough over the Northern Plains will result in a prolonged period of low level cold air advection across the Central Plains through the upcoming week. Highs are expected to top out in the low to mid 30s on Thu.
235 PM CST Mon Dec 12 2022 Tonight and Tuesday: Mid afternoon surface analysis had a >1028mb high centered over the northern Great Lakes region that was ridging back across our CWA and providing a light northeast wind. Also by Tuesday morning a large closed low will become nearly stacked over the central Plains. This low pressure system will track north northeast and send a cold front toward our CWA. WAA will increase through the day ahead of the cold front including a breezy south by afternoon.
A slight increase in total moisture was observed from this morning's Key West sounding, with slight increase in the lower tropospheric moisture depth just above 850 mb beneath a weak 2C inversion, and a narrow moist layer above 500 mb. Otherwise, the trough appears to have insufficient amplitude for any rain for the Keys, although some mid-level cloudiness may be present this evening as the upper flow becomes more northwesterly.
130 PM EST Mon Dec 12 2022 Dry and seasonable weather is expected until a late week low pressure system provides chances for a wintry mix while dropping temperature below normal. More notable clearing is expected overnight as high pressure shifts east and looses lake fetch, causing clearing from the NE to the SW.
1209 PM CST Mon Dec 12 2022 (Rest of Today) A dreary and slightly chilly start this morning with temps currently in the lower 50s and overcast skies.
A few light showers from time to time will remain through Tuesday morning, with rain chances increasing southeast of a line from Waynesboro MS to Destin FL Tuesday afternoon due to a return flow of moisture from the Gulf and a warm front lifting northward.
Light to moderate snowfall to continue across southwestern Idaho and southeast Oregon through mid day today, with conditions lingering along the highway 95 corridor through mid afternoon.
1159 AM EST Mon Dec 12 2022 Dry and seasonably cold conditions are expected to last through midweek as an upper level ridge maintains.
Pronounced upper level ridge axis approaches and moves overhead on Tuesday. Tonight 850 mb flow changes direction, helping to bring in clouds south of I-40, keeping lows warmer in the south but daytime highs a few degrees cooler for Tuesday.
323 PM EST Mon Dec 12 2022 Dry and seasonably cold conditions are expected to last through midweek as an upper level ridge maintains.
1236 PM EST Mon Dec 12 2022 High pressure will control our weather today and tonight.
While there's still some disagreement in surface based CIN among models, the higher res models tend to show an area of reduced CIN, suggesting these initial (discrete) storms will be surface based.
A potent upper level low will track east from the southern Rockies tonight and into the central Plains on Tuesday. The severe threat will generally remain along and north of a Sterling City to Brownwood line, with the highest threat across the northern Big Country. Temperatures will be a little cooler tomorrow, with highs mainly in the low to mid 60s.
Forecast Discussion: An intense upper low continues to deepen over the Intermountain West region. Per 12Z upper level analysis charts, upper level ascent is on the increase over the area with a diffluent region ahead of the trough working overhead and strong mid to upper flow increasing and working into the region from the southwest. The cold front arrives by early morning tomorrow. After the cold front moves through Tuesday morning, skies should clear with the dry slot of the storm system moving overhead into the afternoon. An upper trough and storm system continues to organize as it emerges from the Rockies over the next 12 hours.
A WEAK AREA OF LOW PRESSURE IN THE NORTHEAST GULF OF MEXICO IS PRODUCING SOME ISOLATED SHOWERS OFF THE NATURE COAST.
Looking at radar this morning, showers have mostly ended across the area in the lee of the long wave trough as it moves off to the east. Following that, models continue to show ridging building in offshore, and there is strong agreement that the weather will be dry at least through this week. Valley fog and freezing fog are likely to develop this evening and overnight, especially west side valleys but also likely in the Klamath Basin.
Beyond the convective risks tonight, the westerly momentum Tuesday morning will lead to strong gusty westerly winds for the entire forecast area, probably falling below the High wind threshold, but at least making for a difficult north â south travel Tuesday morning.
Scattered showers are expected to develop across eastern Oklahoma this evening as isentropic lift increases as a potent upper level low organizes over the Rockies. Showers and thunderstorms will become more widespread late tonight as the upper level low emerges from the Rockies into the Plains and the associated Pacific cold front moves into Central Oklahoma. (Tuesday through Monday) The greatest chances of thunderstorms will occur Tuesday morning into early Tuesday afternoon as the cold front advances across eastern Oklahoma and western Arkansas. However, a few surface based storms may be possible late Tuesday morning/ early Tuesday afternoon across portions of southeast Oklahoma and western Arkansas in the warm sector in the vicinity of the advancing cold front. The sun will make its long awaited appearance in the wake of the Pacific cold front Tuesday afternoon as skies clear from west to east.
(Rest of Today) A dreary and slightly chilly start this morning with temps currently in the lower 50s and overcast skies.
Aided by low-level warm air advection, high temperatures will peak in the low to mid 50s on Tuesday.
1155 AM EST Mon Dec 12 2022 Dry and cool today under the influence of high pressure through Tuesday.
The weakening is due to another s/wv that is currently entering the base of the trough north of KLAX.
425 PM EST Mon Dec 12 2022 Dry and seasonably cold conditions are expected to last through midweek as an upper level ridge maintains.
456 PM CST Mon Dec 12 2022 A large and potent mid/upper trough over the Central Great Basin area today is progged to move into the Central Rockies tonight before emerging over the Northern Plains on Tuesday. A 130 knot upper level jet will round the base of this trough while nosing into the Central Plains this evening. Breezy but mild conditions are anticipated with above average highs topping out in the low 60s in southeast KS while some increasing clouds/low level cold air advection keep highs from reaching 50 over our central KS counties. The slow moving mid/upper trough over the Northern Plains will result in a prolonged period of low level cold air advection across the Central Plains through the upcoming week. Highs are expected to top out in the low to mid 30s on Thu.
Snow storm totals of 3 to 5 feet from the weekend storm are impressive over the mountains, with amounts approaching 6 feet over the higher Sierra. 20" The lingering cloud cover over the mountains and foothills will clear tonight as upper level ridging builds in. This will bring dry conditions through most of the week with cold overnight temperatures (around, or slightly below, the freezing mark in the Central Valley, and single digits and teens in the mountains).
I did increase the low temperatures slightly as the surface temperature have only dropped a degree or two so far this evening.
Forecast Discussion: An intense upper low continues to deepen over the Intermountain West region. Per 12Z upper level analysis charts, upper level ascent is on the increase over the area with a diffluent region ahead of the trough working overhead and strong mid to upper flow increasing and working into the region from the southwest. The cold front arrives by early morning tomorrow. After the cold front moves through Tuesday morning, skies should clear with the dry slot of the storm system moving overhead into the afternoon.
Inland frost and sub-freezing temperatures across the interior valleys expected each morning. Meanwhile, day time temperatures will warm into the low to mid 50s for most urban areas while upper 30s to 40s will persist in the mountains. SFO Bridge Approach.
Cool but dry weather will continue into the week as a high pressure builds into the region and light offshore flow persist.
- Much cooler temperatures are expected in the coming days. This has enhanced southerly 850mb winds across the center of the CONUS which in turn has pulled warmer and more moist air into the region. This has resulted in the dissipation of low level fog, but has added thickness to the low level stratus. As it does so, isentropic ascent across and ahead of the warm front initiates a broad area of rain showers. The warm front is expected to pass through around midday. The cold front on the back side of the storm will kick this cloudy, drizzly, and dreary pattern we have been experiencing the past couple of days and replace it with much colder temperatures.
Mostly clear skies have settled over Middle Tennessee as high pressure ridging is present both at the surface and aloft.
As the low pressure responsible for the recent snow across the Northern Rockies moves eastward toward the High Plains, northerly flow will develop locally.
912 PM EST Mon Dec 12 2022 Dry and seasonable weather is expected until a late week low pressure system provides chances for a wintry mix while dropping temperature below normal. More notable clearing is expected overnight as high pressure shifts east and looses lake fetch, causing clearing from the NE to the SW.
(This afternoon through Tuesday night) After days of stratus and fog over the lowlands, the boundary layer is finally scouring out as surface flow veers to south and southwest and increases. This is in response to leeside troughing over the Front Range, which in turn is in response to a massive upper trough digging ESE into the central Rockies. Latest model data and the slow progression of the trough suggest high winds likely through Tuesday night at least, including advisory conditions eastern Culberson County. Over the higher terrain out west, surface winds will veer over the next few hours to westerly, sharpening up a dryline in the east.
On top of the 1 to 3 that has already fallen, seeing some very impressive totals for today in the lower elevations. Broad upper low now centered over northern Utah still shifting east through tonight. As upper low shifts east, broad band of new snow looks to develop across southeast highlands, stretching into the Lower Snake Plain late this afternoon into early evening. Snowfall totals look better over the highlands south and east of Pocatello, so will keep current Winter Weather Advisory in place through tonight. Upper low sags quickly southeast overnight, so snowfall should tail off rapidly to isolated/scattered snow showers into Tuesday, with minimal additional accumulations.
Dry conditions will be continuing through the week as a ridge builds offshore. With the high amounts of moisture present from the recent precipitation, and strong nighttime inversions and low wind speeds resulting from increasing ridging, we'll see morning fog in our sheltered valleys and chilly overnight lows elsewhere with the good radiational cooling, especially where snow is present on the ground. Over the west side, we expect temperatures below freezing in non- coastal areas, with lows in the 20s in some of the sheltered valleys. Another consequence of increased ridging is poor mixing during the day, leading to air stagnation in the area valleys.
At this time the path of this Low is taking a more northeasterly than northerly track which means the start time for this event will be a few hours later than originally thought.
After a few lingering mountain showers this evening, dry and cooler than normal conditions will continue through the end of the week. Freezing temperatures are likely in the San Joaquin Valley for much of this week. After these lingering showers, a dry forecast is in store for all of the central California interior throughout the week, as high pressure builds over the region. A few areas in our northern San Joaquin Valley zones will see overnight lows around freezing tonight, then, probabilities of minimum temperatures of 32 degrees or below are as much as 50 to 70 percent across most Valley locations outside of the larger urban areas.
By Tuesday, a secondary low will develop and move into the Canadian Maritimes, allowing the trough axis to shift towards the Bahamas.
Broad upper low now centered over northern Utah still shifting east through tonight. As upper low shifts east, broad band of new snow looks to develop across southeast highlands, stretching into the Lower Snake Plain late this afternoon into early evening. Snowfall totals look better over the highlands south and east of Pocatello, so will keep current Winter Weather Advisory in place through tonight. Upper low sags quickly southeast overnight, so snowfall should tail off rapidly to isolated/scattered snow showers into Tuesday, with minimal additional accumulations.
318 PM MST Mon Dec 12 2022 The center of the low is now over the Great Basin. With models now better able to resolve the low track. The higher amounts have now pushed farther to the east, mostly in to Big Horn County.
316 PM PST Mon Dec 12 2022 After a few lingering mountain showers this evening, dry and cooler than normal conditions will continue through the end of the week. Freezing temperatures are likely in the San Joaquin Valley for much of this week. After these lingering showers, a dry forecast is in store for all of the central California interior throughout the week, as high pressure builds over the region. A few areas in our northern San Joaquin Valley zones will see overnight lows around freezing tonight, then, probabilities of minimum temperatures of 32 degrees or below are as much as 50 to 70 percent across most Valley locations outside of the larger urban areas.
526 PM EST Mon Dec 12 2022 Dry and seasonable weather is expected until a late week low pressure system provides chances for a wintry mix while dropping temperature below normal. More notable clearing is expected overnight as high pressure shifts east and looses lake fetch, causing clearing from the NE to the SW.
700 PM EST Mon Dec 12 2022 Dry and seasonable weather is expected until a late week low pressure system provides chances for a wintry mix while dropping temperature below normal. More notable clearing is expected overnight as high pressure shifts east and looses lake fetch, causing clearing from the NE to the SW.
High pressure has started to build into the region today. Tuesday an upper level low well out in the pacific is expected to bring a few high clouds to the area. This keeps the ridge over the west coast and brings a very persistent pattern.