Aikyam-Lab/Synoptic-Bench huggingface dataset:
424 AM MST Sun Dec 11 2022 Early this morning, water vapor imagery shows a strong trough over the West Coast. Ahead of this trough, snow is breaking out across the west from a combination of diffluence aloft along with a moist southwest flow. Although the surface gradient is weak, there is enough of a lee side trough and 700 mb winds of 40 to 50 kts to produce the strong winds today. A cold front will push south across the region on Monday. As this occurs, snow will begin to breakout east of the Divide with isentropic lift over the cold front. There remains disagreement on how much moisture and lift will occur as the upper low jumps the Divide late Monday into Monday night.
Radar projections are in good agreement for showers to increase in coverage through the day as a low pressure center approaches the Northern Rockies. The ECMWF maintains a focus for snow on the west side of Idaho and Clearwater counties, and a winter storm watch remains in effect for the Highway 95 corridor above 2000 feet. There is less certainty on snowfall greater than 2 inches since the placement of a deformation band, associated with the low pressure center, is still in question. Lingering moisture in central Idaho and west-central Montana looks sufficient enough for snow to linger into Monday night, but overall a decreasing shower trend is expected as the low pressure system moves off to the east.
As the upper trough moves east, an upper ridge will begin to develop over the Plains, and bring northwest flow aloft which will give us a break from the rain this afternoon through Monday night. Fog will again be possible tonight into Monday morning, and temps will not warm up during the day Monday with highs in the low to mid 50s. The sun should peek out by the afternoon on Monday, hopefully as the upper ridge from the Plains slides eastward.
Early this morning, an upper trough was moving across central Indiana. Will trend toward the cooler side of guidance for highs today and toward the warmer side of guidance tonight with the expected higher cloud cover.
(Today through Monday Night ) Precip is beginning to come to an end across southern parts of the area this morning as a cold front continues to make southern progress across northern LA. Sfc ridging will remain in place just northeast of the area and with abundant cloud cover, temperatures will be fairly cool across much of the forecast area. H500 ridging will briefly move over the area Monday in advance of a deepening cyclone headed eastward across the western US. Sfc ridging will begin to shift eastward and low level flow will become easterly Monday then southerly Monday night.
627 AM EST Sun Dec 11 2022 Presently, a cold front is tracking across the forecast area. Upper-level ridging continues to build through this afternoon and evening and firmly establishing itself over the area for Monday. Temperatures are forecast to be slightly cooler for Monday but the area remaining dry. This ridge will keep the weather rather quiet for the remainder of the forecast period.
Dry conditions will then continue through Monday as high pressure builds over the area with the approaching upper level ridge.
344 AM CST Sun Dec 11 2022 Forecast Highlights: -Dense freezing fog is occurring for some this morning. Forecast Discussion: Dense freezing fog with visibilities less than a quarter of a mile is ongoing early this morning across eastern Kansas. In the meantime, temperatures will remain below freezing until after 15Z, so the fog could create some slick spots on sidewalks, driveways and area roadways.
Dewpoints are currently in the mid 60s and temperatures are generally in the lower 70s. Ridging will dominate the sensible weather elements. Lower-level ridging currently situated over the northeastern Gulf of Mexico will continue to shift eastward towards Florida, and generally northerly winds will become light and, at times, variable.
425 AM EST Sun Dec 11 2022 Presently, a cold front is tracking across the forecast area. Upper-level ridging continues to build through this afternoon and evening and firmly establishing itself over the area for Monday. Temperatures are forecast to be slightly cooler for Monday but the area remaining dry. This ridge will keep the weather rather quiet for the remainder of the forecast period.
515 AM CST Sun Dec 11 2022 (Today through Monday Night ) Precip is beginning to come to an end across southern parts of the area this morning as a cold front continues to make southern progress across northern LA. Sfc ridging will remain in place just northeast of the area and with abundant cloud cover, temperatures will be fairly cool across much of the forecast area. H500 ridging will briefly move over the area Monday in advance of a deepening cyclone headed eastward across the western US. Sfc ridging will begin to shift eastward and low level flow will become easterly Monday then southerly Monday night.
Offshore, a spinning low pressure system is presented nicely in visible satellite imagery, with bands of light showers wrapping around the periphery of this feature. (previous) Small low pressure area near Buoy 41010 is producing N/NW winds around 15 knots across the local Atlc waters.
It's possible light -shsn or flurries could linger into late morning at some north central locations in a developing northerly upslope flow on the backside of the departing low/trough. Expect max temp readings generally from around 30F to the lower 30s today.
238 AM MST Sun Dec 11 2022 Synoptic Setup: Current setup begins with a ridge exiting the northern Plains for the Mississippi Valley. Behind it lies a huge trough developing over northern California and digging southeast into the Four Corners. To the north an Arctic airmass and strong cold front are developing over central Alberta and beginning their march down the Front Range. The Alberta cold front should hit early Monday morning. Meanwhile, the base of the Cali trough will reach the Front Range of Colorado. 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.
841 AM EST Sun Dec 11 2022 The region is between an area of low pressure to the southeast, and a frontal system just to the north this morning. Areas south of Gainesville have a chance at the lower 70s.
A cold upper trough will continue to bring showers with light snow accumulations above 2000 feet today through this evening.
Aloft, upper level flow became mostly zonal as the upper level trough flattened. At the surface, high pressure situated over the northeastern Gulf of Mexico should keep light winds, generally from the north and northeast. Then, a change in the pattern is expected by the other half of the week as a deep upper level low sets up over the central portion of the U.
615 AM CST Sun Dec 11 2022 Today and Tonight: A cold front associated with a low pressure system over the Great Lakes has been slowly pushing southward through our forecast area overnight. Trajectories of moist air along and over the cold frontal boundary will keep chances for rain and thunder in at least portions of the forecast area into this evening. The cloud cover and rain should dampen the temperature curve today, with highs expected to be only around 5-10 degrees warmer than current morning lows. Temperatures will be slightly cooler Monday (but still above climo) with highs in the middle low 60s to low 70s. Overnight lows will remain in the lower to upper 50s.
While dry air is slowly advecting into the region along the northwesterly flow on the eastern side of the low-level ridge, a strong inversion in the low levels will keep that air from making much of a dent on the cloud deck. A strong mid-level trough is coming onshore in the western CONUS on Sunday, and will steadily march eastward over the first half of the work week.
651 AM EST Sun Dec 11 2022 Aloft, upper level flow became mostly zonal as the upper level trough flattened. At the surface, high pressure situated over the northeastern Gulf of Mexico should keep light winds, generally from the north and northeast. Then, a change in the pattern is expected by the other half of the week as a deep upper level low sets up over the central portion of the U.
1217 PM EST Sun Dec 11 2022 The region is between an area of low pressure to the southeast, and a frontal system just to the north this morning. Areas south of Gainesville have a chance at the lower 70s.
Since the midlevel ridge axis will remain west of us through the diurnal mixing cycle tomorrow, and stratus will likely struggle to decrease, temperatures will probably be similar to today.
An area of heavier rain showers (probably with some graupel mixed in) has formed across much of Elmore County, with another smaller area in the Lower Treasure Valley.
(This afternoon through Monday night) WV imagery shows the next upper trough making landfall on the Oregon/California border, in turn developing southwest flow aloft over West Texas and Southeast New Mexico this afternoon.
115 PM EST Sun Dec 11 2022 Low clouds linger behind a cold front that has push south and southeast of the area. Presently, a cold front is tracking across the forecast area. Upper-level ridging continues to build through this afternoon and evening and firmly establishing itself over the area for Monday. Temperatures are forecast to be slightly cooler for Monday but the area remaining dry. This ridge will keep the weather rather quiet for the remainder of the forecast period.
1134 AM CST Sun Dec 11 2022 (Today through Monday Night ) Precip is beginning to come to an end across southern parts of the area this morning as a cold front continues to make southern progress across northern LA. Sfc ridging will remain in place just northeast of the area and with abundant cloud cover, temperatures will be fairly cool across much of the forecast area. H500 ridging will briefly move over the area Monday in advance of a deepening cyclone headed eastward across the western US. Sfc ridging will begin to shift eastward and low level flow will become easterly Monday then southerly Monday night.
The TROWAL from the occluding cyclone and its PW airmass of 1 inch will approach sw WI from 21-00Z, thus chances for showers at that time. Dry conditions will then continue through Monday as high pressure builds over the area with the approaching upper level ridge.
The axis of this trough is expected to reach our forecast area northwest of I-65 by late this afternoon, and then weaken while moving very slowly southeastward through Monday.
With dew points in the lower to mid 50s and cloud cover, overnight lows will fall near dew points.
In the mid to upper levels, the ridge has been squashed southward towards Central America as nearly all upper-air stations across Florida noted a decrease in heights. However, even though heights have fallen, there is no distinct sign of a trough moving into the area. Rather, this is probably more due to the ridge moving away from the area. In the low levels, not much change has occurred. The ridge remains in place over the northeastern Gulf extending northeastward over Georgia and into South Carolina. The center of this ridge was located approximately near Valdosta, Georgia.
As a result of the expected fog and stratus, kept a rather narrow diurnal curve with tonight's minimums on the high end of guidance (40s) and tomorrow's afternoon highs on the low end of guidance (50s).
The leading edge of a large low pressure system will continue moving away to the east tonight.
Expect that there should a bit more clearing around this area in the next couple of hours before sunset before the low clouds and fog begin to form again where the RAP/NAM soundings continue to show low level moisture being trapped below an inversion through the day on Monday. Still expect dry weather through Monday night as the upper ridge seen in the water vapor over the Plains builds east tonight. The first chance of rain from the well advertised upper low currently digging into the West Coast will move into central Missouri by late Monday night when both the NAM/GFS are showing increasing low level moisture convergence and mid level ascent.
(Rest of Today) Mid-tropospheric westerly flow of 30-40 knots will gradually veer to northwest over the course of the afternoon, as a deepening northern stream cyclone tracks southeastward across the eastern Great Lakes and into NY. At the surface, a diffuse trough related to the lower-latitude disturbance will continue to spread slowly southeastward through the TN Valley today, likely not exiting our CWFA until close to 12/00Z.
Dry but cool weather will prevail this week with high pressure.
1120 AM EST Sun Dec 11 2022 Low clouds linger behind a cold front that has push south and southeast of the area. Presently, a cold front is tracking across the forecast area. Upper-level ridging continues to build through this afternoon and evening and firmly establishing itself over the area for Monday. Temperatures are forecast to be slightly cooler for Monday but the area remaining dry. This ridge will keep the weather rather quiet for the remainder of the forecast period.
Overall sunny skies with temperatures in the low 80s this afternoon. High temperatures will remain in the lower 80s across South Florida.
1202 PM CST Sun Dec 11 2022 (Rest of Today) Mid-tropospheric westerly flow of 30-40 knots will gradually veer to northwest over the course of the afternoon, as a deepening northern stream cyclone tracks southeastward across the eastern Great Lakes and into NY. At the surface, a diffuse trough related to the lower-latitude disturbance will continue to spread slowly southeastward through the TN Valley today, likely not exiting our CWFA until close to 12/00Z.
Latest analysis of the mid to upper levels continue to show the ridge over Central America with more of a westerly zonal flow across the Gulf of Mexico and over Florida. In the low levels, the ridge continues to slowly meander southward over Florida and the eastern Gulf while slowly weakening.
Temperatures may initially be near freezing, leading to isolated slick spots on roads.
A cold upper trough will continue to bring showers with light snow accumulations above 2000 feet through this evening. Areas farther north may continue to see some isolated showers, mainly over the higher terrain. Any inland valley areas that do manage to clear out will likely see fog or freezing fog and this may be dense at times. Temperatures will be chilly, but could stay slightly warmer than expected in areas that see fog. The coastal areas are more likely to stay clear, but still will likely drop into the low 30s. Monday morning there may be a few light showers lingering as the low slowly pulls out of the area. This will keep high temperatures cool, some areas may not make it out of the 30s if the low clouds and fog stick around until early afternoon.
A large upper level low will move into the western United States today then into the Central Rockies tomorrow. This will result in surface lee troughing across eastern Colorado to deepen bringing strong southerly winds to western Kansas through tomorrow. The higher dewpoints across the area overnight will keep temperatures from falling as we seen with previous nights and allow for lows ranging from the upper 20s across west central Kansas to upper 30s across central Kansas. Lee troughing will continue to deepen tomorrow as this system approaches leading to strong southerly winds across western Kansas.
934 PM EST Sun Dec 11 2022 Update One challenge for the night is whether we will see some patchy flurries or drizzle/freezing drizzle. A shallow cooler and moist airmass was filtering down from the northeast. But models are forecasting the low level convergence to increase slightly late tonight. Currently the surface temperatures were mostly above freezing.
The trough axis is over CA this afternoon and we will see a vort max dig down the coast later today. 60" with the highest totals in the southern Sacramento Valley and northern San Joaquin Valley.
High pressure will continue to push this boundary further south as drier and slightly cooler air moves over the area.
554 PM CST Sun Dec 11 2022 (This afternoon through Monday night) WV imagery shows the next upper trough making landfall on the Oregon/California border, in turn developing southwest flow aloft over West Texas and Southeast New Mexico this afternoon.
Freezing temperatures are likely in the San Joaquin Valley for much of this week.
543 PM CST Sun Dec 11 2022 (Tonight) Light rain showers associated with the slow-moving cold front have gradually tapered off for the most part, with only a few sprinkles left in southeastern portions of our CWA. Low temperatures will reside in the low to upper 40s with NNE winds.
This is being triggered by the return flow ahead of the core upper level low to our west. In fact, the low level moisture signature is stronger for Monday morning over what we saw this morning.
Quieter weather with lighter winds will prevail this week with much colder temperatures expected along with areas freezing fog. Quieter weather is expected for the upcoming week as a high pressure ridge attempts to nudge into the region.
Cool but drier weather is on tap for the rest of the week as a upper level ridge builds into Western Washington.
Unlike today, the low clouds/fog should lift by mid/late morning allowing for sunshine and warm temperatures.
An upper level ridge will maintain fair weather through midweek. High pressure sfc and aloft will control things for the next few days. NW wind and slight CAA will result in temps staying slightly cooler Mon than Sun in the W, but close (40F) in the SE. A sharp and progressive upper ridge will crest over the region late Wed. However, it appears that wet bulb temps will gradually rise late Wed night as the precip and warmer air aloft moves in from SW to NE.
Drier conditions expected Monday through Tuesday as a large area of high pressure builds into the Great Lakes area for the first half of the week.
The 00Z FL RAOBs sampled meager height falls from 925 to 700 mb, adding evidence to the erosion of the low-level ridging. The steep lapse rates above the 800 mb inversion corroborate the lower heights aloft. Temperatures range from 65 in Big Pine (the radiational cooling capitol of the Keys) to the lower 70s.
(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.
A short wave trough is moving across the region with some light precipitation over southeast Georgia. High pressure building in from the north will reinforce the northeaster with overcast skies continuing across most of the area today.
1230 AM EST Mon Dec 12 2022 (06Z TAFS) Light showers due to an upper trough which will be exiting the area over the next 12-14 hours.
A large upper level low will move into the western United States today then into the Central Rockies tomorrow. This will result in surface lee troughing across eastern Colorado to deepen bringing strong southerly winds to western Kansas through tomorrow. The higher dewpoints across the area overnight will keep temperatures from falling as we seen with previous nights and allow for lows ranging from the upper 20s across west central Kansas to upper 30s across central Kansas. Lee troughing will continue to deepen tomorrow as this system approaches leading to strong southerly winds across western Kansas. Strong winds continue overnight curling to the southwest before shifting to the northwest Tuesday behind a cold front. Cold air advection behind this system will bring much cooler temperatures to western Kansas.
- Windy and cooler temperatures will be expected the remainder of the week.
1242 AM EST Mon Dec 12 2022 Aviation One challenge for the night is whether we will see some patchy flurries or drizzle/freezing drizzle. A shallow cooler and moist airmass was filtering down from the northeast. But models are forecasting the low level convergence to increase slightly late tonight. Currently the surface temperatures were mostly above freezing.
The TROWAL from the occluding cyclone and its PW airmass of 1 inch will approach sw WI from 21-00Z, thus chances for showers at that time.
240 AM EST Mon Dec 12 2022 High pressure will control our weather today and tonight.
Southeast Michigan will hold position well downstream over the next 48 hours, with conditions marked by building high pressure beneath weakly confluent northwest flow. Lowering inversion base under strengthening subsidence as upper ridging encroaches increases the probability for breaks in the cloud or a window of clearing Tuesday in advance of the next round of system related high cloud. Elongated ribbon of moist isentropic ascent will materialize within an expanding region of elevated warm air advection within the eastern flank of the central plains closed low. This process initially driven by increasing magnitude and depth of southwest flow, anchored by a 125 knot upper jet arcing through the trough base.
With a cold Canadian high to the north, and two adjacent lows in the Great Plains and Canadian Maritimes, a high pressure axis will develop over the northeast. Tuesday will maintain subsidence and high pressure with continued northeast flow.
151 AM EST Mon Dec 12 2022 Dry and cool today under the influence of high pressure. High pressure Tuesday.
After mid week, a change in the weather pattern is expected as a deep upper level low sets up over the central portion of the U.
129 AM EST Mon Dec 12 2022 While high pressure centered WELL to our north will build into the region today. the low clouds south of Lake Ontario will be slow to dissipate.
With a cold Canadian high to the north, and two adjacent lows in the Great Plains and Canadian Maritimes, a high pressure axis will develop over the northeast. This has allowed for, and will continue to provide chances of, freezing drizzle in the ridges with the aid of orographic lift in maintaining shallow saturation. Drizzle chances for the ridges will taper off by morning with diminishing 850mb CAA and veering surface winds. Tuesday will maintain subsidence and high pressure with continued northeast flow.
1240 AM EST Mon Dec 12 2022 High pressure builds in from the north through Tuesday before weakening.
346 AM EST Mon Dec 12 2022 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.
Light rain and snow showers on the back side of an upper low may occur near the North Coast and across Del Norte county this morning. Freezing temperatures are expected again for coastal areas and may briefly dip below 30F late tonight into early Tuesday morning for some coastal valleys. Interior valleys will be even colder, but it is winter and freezing temperatures are not that unusual for mid December. Northerly winds will gradually diminish today as high pressure builds across the area.
428 AM EST Mon Dec 12 2022 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.
More notable clearing is expected overnight as high pressure shifts east and looses lake fetch, causing clearing from the NE to the SW. Tuesday will maintain subsidence and high pressure with continued northeast flow.