Aikyam-Lab/Synoptic-Bench huggingface dataset:
Shower chances will gradually diminish in northern areas during the afternoon and evening but will linger longer in southern areas as the trough axis slowly works south. The upper level trough will push south and east on Wednesday ushering in quieter weather. Short wave ridging will bring clearing skies Wednesday night. This will result in even colder low temperatures with mid 20s to lower 30s in the lower elevations.
254 AM MST Tue Feb 28 2023 Water vapor analysis shows upper trough axis centered from western British Columbia southward through WA/OR into NV. As the low pressure system develops over the forecast area, snow chances will increase after 19-20z this afternoon across the Black Hills and NW SD under broad large-scale ascent, strong low-level frontogenesis, and increasing isentropic ascent. Overall, expect 1-3 inches along the higher elevations of the Black Hills, although convective enhancement could result in locally higher amounts in spots. NBM snow probabilities support lower snowfall potential, with 15-25% probabilities of >2" of snow, primarily limited to the highest elevations. Looking ahead, ensemble means and cluster analysis highlight persistent western troughing in the 4-10 day timeframe, with potential for continued cool and active weather into the second week of March.
640 AM EST Tue Feb 28 2023 A cold front will move offshore early today. High pressure will build in from the Mid-Atlantic through mid-week.
522 AM MST Tue Feb 28 2023 Water vapor analysis shows upper trough axis centered from western British Columbia southward through WA/OR into NV. As the low pressure system develops over the forecast area, snow chances will increase after 19-20z this afternoon across the Black Hills and NW SD under broad large-scale ascent, strong low-level frontogenesis, and increasing isentropic ascent. Overall, expect 1-3 inches along the higher elevations of the Black Hills, although convective enhancement could result in locally higher amounts in spots. NBM snow probabilities support lower snowfall potential, with 15-25% probabilities of >2" of snow, primarily limited to the highest elevations. Looking ahead, ensemble means and cluster analysis highlight persistent western troughing in the 4-10 day timeframe, with potential for continued cool and active weather into the second week of March.
Water vapor analysis shows upper trough axis centered from western British Columbia southward through WA/OR into NV. As the low pressure system develops over the forecast area, snow chances will increase after 19-20z this afternoon across the Black Hills and NW SD under broad large-scale ascent, strong low-level frontogenesis, and increasing isentropic ascent. Overall, expect 1-3 inches along the higher elevations of the Black Hills, although convective enhancement could result in locally higher amounts in spots. NBM snow probabilities support lower snowfall potential, with 15-25% probabilities of >2" of snow, primarily limited to the highest elevations. Looking ahead, ensemble means and cluster analysis highlight persistent western troughing in the 4-10 day timeframe, with potential for continued cool and active weather into the second week of March.
Temperatures are ranging from the low to the upper 80s especially in our usual hot spot Big Pine Key. Deep layer ridging draped across Cuba continues to suppress convective development with stable thermodynamic profiles and unusually dry mid to upper levels. Just like last night, localized extremes that are sheltered from warmer marine waters may make it down into the lower 60s. Tomorrow, winds will freshen as an upper level trough starts its journey across the Southern Plains. These gentle to moderate breezes will persist for a few days until the trough reaches the Mississippi River Valley while dragging a cold front along behind it.
This will help push a cold front into Oklahoma tonight. The air mass behind this front will not be overly cold as daytime temperatures on Wednesday are expected to be in the lower 60s northern Oklahoma to lower 70s along the Red River.
338 PM EST Tue Feb 28 2023 An area of high pressure will drift east across the region tonight bringing up fair, tranquil weather. A weak area of low pressure and warm front will track west of Pennsylvania late Wednesday, with some clouds and isolated to scattered showers mainly over the northwest mountains of the state.
Overnight lows will be warmer than what we have experienced the last few mornings, with most locations dropping into the 50s and are far southeast counties only reaching the lower 60s. Highs on Wednesday will again be well above seasonal normals, but a little extra cloud cover should keep temperatures slightly cooler than what we are expecting today.
High temperatures tomorrow are forecast in the low 80s near the coast and mid 80s inland.
There is a broad trough over the region today with several embedded smaller circulations. Minimal impacts from the showers are expected during the daytime due to the higher solar angle and more potent sunshine. Tomorrow, the energy associated with this embedded low circulates around the broader trough and moves into southern Oregon and southern Idaho.
(Rest of Today) Unamplified, westerly flow aloft will persist across the TN Valley today, as our region will remain along the northern rim of a strong 500-mb ridge centered across the northwestern Caribbean Sea. At the surface, winds will remain light/variable as an area of high pressure initially across IA shifts eastward into the eastern Great Lakes vicinity.
As the longwave trough continues to slide across the region today, banded snow showers continue across the south.
Clouds will increase overnight ahead of the upper trough digging across southern California and will help keep temps in the mid 30s to upper 40s. These clouds will remain through at least late morning as the upper trough transitions to a closed low and begins pushing eastward towards Arizona. The 700 gradient will begin to tighten ahead of the upper low and will result in a 40-50 knot jet over the FA. Conditions will be quieter across the Rolling Plains where a weak backdoor cold front will settle in during the morning before winds veer to the southwest once again by the afternoon.
933 AM MST Tue Feb 28 2023 Fog was gradually dissipating over southeastern areas, and down into Sheridan County, as an inverted trough gradually shifts north and east. STP Satellite imagery showed an upper trough deepening over the Pacific Northwest. A piece of the trough will kick across southern Montana and northern Wyoming and be the primary weather maker the next 36 hours. The inverted trough lingers through the night tonight. A splitting trough moves closer the western zones Wednesday afternoon and this will combine with lingering low level instability to leave a slight chance of snow showers going Wednesday, into Wednesday evening (mainly over western zones).
141 PM MST Tue Feb 28 2023 20z surface analysis had low near KECS with warm front into northern SD and cold front into southern ID. Low level southerly flow increases with significant frontogenetic forcing along warm front in far northwest SD. Expect snow to rapidly develop late this afternoon along warm front with potential convective elements and 1"/hour snowfall rates for 2-3 hours resulting in 2-5" of snow for the winter weather advisory area - locally higher amounts near the SD/ND border. As surface cyclone deepens, cold front is swept eastward with 3-5mb/3hr pressure rises behind it and modest cold air advection.
Generally zonal flow aloft continues through Wednesday with the influencing upper ridge continuing to nose into the northern Gulf. Clouds for the most part should diminish today as the slightly drier air moves into the area, and with this expecting some more record high temps to occur across the region this afternoon with temps climbing into the low 80s for most areas. On Wednesday, even with the increasing cloud cover, low level warm advection continues to aid in warmer highs ranging mainly in the low 80s.
A weak warm front will shift north through the region Wednesday, bringing some increase in moisture, and leading to a few showers.
a cold front moves through the area. Moisture in the 850-500mb layer steadily increases after midnight during the night in between an approaching upper level trough to our northwest and a closed upper level low near the Arizona/New Mexico border.
This Evening/Tonight Currently this afternoon, a fairly benign pattern is in place with zonal flow aloft and high pressure near the Great Lakes region. Overnight, high pressure will shift eastward with some height rises and strengthening of the upper jet to our north, where another low will move into the Northern Plains.
Deep layer ridging planted over Cuba controls our sensible weather. Temperatures across the island chain are currently near 80 and expected to rise to the lower to mid 80s this afternoon. From synopsis, Light to gentle south to southwest breezes are expected today, becoming variable and shifting to east to southeast tonight as high pressure retreats eastward over the western North Atlantic.
High pressure remains in control for most of the work week with mild evenings and warm afternoons expected.
The track of the low will determine the placement of the greatest snowfall, with some locations getting 2-3 inches of snow and others getting nothing. Surface winds: SE-SW 10-25 kt, becoming S to W 10-20 kt after around 06z/Tue behind cold front.
Issued by National Weather Service Little Rock AR 1136 AM CST Tue Feb 28 2023 Today will be a dry and sunny day with temperatures in the low to mid 70s.
308 PM EST Tue Feb 28 2023 High pressure builds into the region tonight with dry weather returning.
330 PM EST Tue Feb 28 2023 High pressure will build overhead tonight. An area of low pressure will track to our north late Wednesday into Wednesday night.
330 PM EST Tue Feb 28 2023 High pressure shifts offshore Wednesday keeping benign weather in place across ENC through midweek.
(Rest of today through Wednesday) High pressure remains locked in across the region.
An upper level low off the Washington coast is still driving our weather today and Wednesday. Today a wave off this low is exiting our eastern areas. The current model run shows the upper level low off the Washington coast diving south over California/western Nevada this evening into tomorrow. As this low drops south it will spin off another wave coming into our area in southerly flow starting early this evening and continuing into early Wednesday morning. Late Wednesday afternoon into the evening high pressure starts building in bringing drier weather with northerly winds starting to drop over the divide.
Otherwise, quiet conditions for now this evening as high pressure remains in control across the area. High pressure remains in control for most of the work week with mild evenings and warm afternoons expected.
Forecast challenges continue to revolve around the low pressure system affecting the region through Wednesday. Still believe an east- west oriented, transient band will develop on the north side of this low in a deformation zone.
High-res models have been showing a band of frontogenesis in the Iron Range that will bring snow a little ahead of the low pressure system. However, as this system has shifted north, resultant higher totals along the Highway 2 corridor have caused all of Cass, Aitkin and Carlton counties as well as southern St.
Heading into Wednesday, drier conditions will prevail as flat ridging develops in the wake of the inverted trough. Snow begins to move into the western mountains during the afternoon and evening as a split trough moves east into the Rockies. Temperatures will be a few degrees cooler on Wednesday, with temperatures topping out into the 20s and lower 30s.
615 PM EST Tue Feb 28 2023 (Rest of today through Wednesday) High pressure remains locked in across the region.
307 PM CST Tue Feb 28 2023 Forecast challenges continue to revolve around the low pressure system affecting the region through Wednesday. Still believe an east- west oriented, transient band will develop on the north side of this low in a deformation zone.
Winds will likely be between 10 to 15 mph with higher gusts on occasion and the highs will once again be in the low to mid 80s areawide.
652 PM EST Tue Feb 28 2023 High pressure will gradually build over the region through mid week before a strong cold front is expected to affect the area late week. But with weakening/decoupling winds this evening and higher dewpoint air across the Georgia counties, some fog is certainly possible, particularly across the far southern counties where surface condensation pressure deficits will be the lowest.
254 PM MST Tue Feb 28 2023 Upper trof lifting out into Wyoming this afternoon with a drying and subsident airmass spreading over Northern Colorado. Weak ridging aloft moves in later tonight but this will be short lived in advance of next upper low dropping into the southern Great Basin by late Wednesday afternoon. Wednesday night, a trough and cutoff low moves east across the Desert SW. As the low moves east, SW flow aloft advects in modest moisture into the region along with QG ascent. This will keep snow showers going over the high country.
835 PM EST Tue Feb 28 2023 High pressure will build overhead tonight. An area of low pressure will track to our north late Wednesday into Wednesday night.
A high pressure ridge rebuilds northward toward ECFL on Wed with a weaker pressure gradient in place and SW winds 5-10 mph. High pressure builds back in from the southeast producing dry and unseasonably warm conditions.
451 PM MST Tue Feb 28 2023 20z surface analysis had low near KECS with warm front into northern SD and cold front into southern ID. Low level southerly flow increases with significant frontogenetic forcing along warm front in far northwest SD. Expect snow to rapidly develop late this afternoon along warm front with potential convective elements and 1"/hour snowfall rates for 2-3 hours resulting in 2-5" of snow for the winter weather advisory area - locally higher amounts near the SD/ND border. As surface cyclone deepens, cold front is swept eastward with 3-5mb/3hr pressure rises behind it and modest cold air advection.
444 PM MST Tue Feb 28 2023 Upper trof lifting out into Wyoming this afternoon with a drying and subsident airmass spreading over Northern Colorado. Weak ridging aloft moves in later tonight but this will be short lived in advance of next upper low dropping into the southern Great Basin by late Wednesday afternoon. Wednesday night, a trough and cutoff low moves east across the Desert SW. As the low moves east, SW flow aloft advects in modest moisture into the region along with QG ascent. This will keep snow showers going over the high country.
So, it seems that darn groundhog may have been More snow will impact western WY early this morning, mainly before dawn as an upper low dives south from the PACNW into the Desert Southwest Region this morning through tonight. As the trough associated with this upper low passes through WY this afternoon into tonight; it will bring in some moisture with southerly/southwesterly flow and isentropic lift across southern portions of the area up into central portions of the area. Winds then quickly shift northwesterly as the trough axis passes overnight.
This could mean the main area of snow will stay north of the border as the low tracks east overnight, but any wobble could still result in accumulations south of the border as well. Forecast challenges continue to revolve around the low pressure system affecting the region through Wednesday. Still believe an east- west oriented, transient band will develop on the north side of this low in a deformation zone.
1021 PM PST Tue Feb 28 2023 The region will remain in an active and unsettled pattern through the week, with cooler than normal temperatures and several rounds of precipitation mainly in the form of snow. Expect slick road conditions from the combination of slush on the roads, refreezing of moisture on roads and freezing fog. /SVH 06Z TAFS: The Inland Northwest remains under a cold, unstable trough of lower pressure. Areas of freezing fog is expected to expand across the northern mountain valleys with a 40-60% chance of low IFR conditions due to freezing fog at KGEG-KSFF-KCOE late tonight into Wednesday morning.
Deep layer ridging remains in place with substantial subsidence and dry air aloft meaning that near nil rain chances will prevail through the overnight. Light to gentle variable winds will gradually clock around to the east and southeast late tonight as high pressure located over the western Atlantic recedes further eastward.
103 AM EST Wed Mar 1 2023 High pressure will gradually build over the region through mid week before a strong cold front is expected to affect the area late week. Weakening/decoupling winds tonight and higher dewpoint air across the Georgia counties, some fog is certainly possible, particularly across the far southern counties where surface condensation pressure deficits will be the lowest.
It may seem like the forecast for our area is stuck in a warm, rain free, fog-filled loop, that's thanks to high pressure remaining in control.
1014 PM EST Tue Feb 28 2023 High pressure shifts offshore Wednesday keeping benign weather in place across ENC through midweek.
1020 PM EST Tue Feb 28 2023 High pressure will gradually build over the region through mid week before a strong cold front is expected to affect the area late week. But with weakening/decoupling winds this evening and higher dewpoint air across the Georgia counties, some fog is certainly possible, particularly across the far southern counties where surface condensation pressure deficits will be the lowest.
Wednesday will be generally dry with high pressure over the area.
With Canadian high pressure diving into central and eastern North Dakota this afternoon and evening, winds will become light and variable in the central and east, while remaining relatively light in the west. Lows tonight are progged to range from within a few degrees of 10 below in the east to the lower teens above zero in the southwest.
Otherwise a weak cold front will be moving into the Big Country this morning, shifting winds to the north at 5 to 10 mph until mid afternoon, when they shift back south. It will be cooler in the Big Country with highs in the lower to mid 70s, with highs in the upper 70s to mid 80s farther to the south.
339 AM CST Wed Mar 1 2023 For this afternoon, high pressure will dominate the sensible weather, beginning with rapidly weakening winds already heading toward sunrise. A little cooler , fall-like highs in the 50s area- wide.
As the upper level forcing moves toward the Desert Southwest with the associated 500MB digging trough, these snow showers should continue to diminish in coverage and intensity this morning. Meanwhile, ridging in the Gulf of Alaska will weaken as it moves to towards the northwest US through Thursday. This puts Montana under northwest flow in anticipation of another trough developing over the Yukon.
An upper-level trough makes way across southern portions of western CONUS, brining an increase of south and west winds to the region. This will quickly propagate eastward, allowing for a relatively weak upper-level ridge to take its place. Primary concern is the strengthening pressure gradient from the aforementioned trough and incoming ridge, which will lead to increased winds, particularly along the Rocky Mountain Front and adjacent plains, the Montana Hwy 200 Corridor, and portions of Southwest Montana south of the I-90 Corridor. Given the latest probabilistic data and the enhancement of mountain wave turbulence over the Rocky Mountain Front, have opted to upgrading the High Wind Watch to a High Wind Warning for southwesterly winds of 30 to 50 mph, gusting upwards of 85 mph along the Rocky Mountain Front, and upwards of 70 mph along the adjacent plains.
Cold mornings, otherwise dry and warmer the second half of the week. Increasing gusty southwest winds today out ahead of approaching cold front will continue overnight. Wind advisory in effect for the lower elevations with higher winds in the mountains that is covered in the Winter Storm Warning product.
Going into today, high pressure over the region will provide the area with another decent day in advance of an approaching low pressure system late tonight through Thursday, that will bring accumulating snows to the area. Overall the low complex will shift south of the cwa, across Oklahoma and northern Texas. Easterly flow from the surface to 850mb due to the low south of the cwa and high pressure north, will provide a persistent upslope/orographic fetch over the region.
At the surface, a very weak cold front/trough stretches from eastern Nebraska into the OK Panhandle and is associated with some gusty northwest winds across central and south central KS. Powerful west coast upper low is expected to continue tracking into the Desert Southwest tonight into Thu morning and out into the Southern High Plains for Thu afternoon. The transition from rain to snow will be solely dependent on the thermal profile in the lowest few thousand feet where temps may get warm enough to melt any snowflakes falling through the column. Upper low will quickly track east, and by Fri afternoon will be moving into the Ohio/Tennessee Valleys. A weak cold front is then expected to move through for the start of the work week, knocking temps back to seasonal normals.
Depending on how much clearing occurs early Thu AM, both very cold temps (single digits above/below zero everywhere outside of the ern Magic Valley/Raft River region/lower Snake Plain) and freezing fog will be possible. any low stratus may keep the sfc warmer and take the edge off fog, but plenty of snow cover could also drive sfc cooling.
Radar shows lingering snow showers across the northern Sierra early this morning as the deep trough closes off to our south over central California. Current temperatures are a little cooler compared to 24 hours ago and range from mainly the single digits and teens in the mountains to the 30s across the Central Valley.
a cold front moves through the area. Moisture in the 850-500mb layer steadily increases after midnight during the night in between an approaching upper level trough to our northwest and a closed upper level low near the Arizona/New Mexico border. Low temperatures are forecast to be in the lower to middle 20s. the forecast area will be under wraparound snowfall during the day and into the evening as the upper low moves east into northern Texas during the afternoon, lifting slightly northeast into Arkansas overnight.
631 AM EST Wed Mar 1 2023 (Today through Thursday) Models continue to show strong and deep high pressure remaining across much of the region, with the warmer than normal weather pattern prevailing through the short term.
Any remaining shower activity will move out of the area by around sunrise this morning with skies clearing behind the upper low, allowing overnight temperatures to dip lower in some places. Expect Thursday morning lows a couple of degrees cooler than this morning, with the exception of coastal areas, the bay shoreline, and the North Bay where temps are expected to be similar to this morning. Slight warm up late Thursday with temps a few degrees warmer but still below normal. Highs generally in the upper 50s with morning lows in the lower 40s.
The last scattered showers associated with the upper level trough are fading over the Cascades early this Wednesday morning. A period of calm is expected across southern Oregon and northern California as an upper ridge becomes the defining atmospheric feature through Wednesday and into Thursday morning. Thursday morning, a weak cold front will approach from the Pacific, bringing significant precipitation chances to coastal ranges and the Cascades.
922 AM EST Wed Mar 1 2023 Weather stays dry and hot under the influence of high pressure today. (Today through Thursday) Models continue to show strong and deep high pressure remaining across much of the region, with the warmer than normal weather pattern prevailing through the short term.