Aikyam-Lab/Synoptic-Bench huggingface dataset:
343 AM CST Mon Jan 27 2020 Early morning satellite imagery shows a compact closed low progressing southeast through Iowa, which prompted freezing drizzle and flurries across a portion of the region overnight. The latest surface observations and webcam images show that freezing drizzle and dense fog have developed across much of southwest MN with flurries and freezing drizzle across portions of southeast SD. in mainly northwest flow aloft, ahead of strong ridging off the west coast. On Tuesday and Tuesday night, a north-south oriented trough passing through the Northern and Central Plains is expected to develop light precipitation in the region.
Currently, the cool high pressure system with stratus entrenched extended from the high center in northern Manitoba with its axis extending into the eastern Dakotas and western Minnesota. At upper levels, a low center over southeastern South Dakota continued moving southeast out of our area with weak ridging over the Front Range.
A short wave trough moving across the region will provide some upper support but will have trouble producing much or any precipitation due to lack of moisture and low level warm advection and convergence. There may be enough lift and saturation in low levels to get some freezing drizzle or light snow but little or no accumulation is expected.
430 AM EST Mon Jan 27 2020 Occasional light snow and flurries, possibly mixed with some patchy freezing drizzle is possible into early this morning.
A freezing fog advisory has been issued for the county till 10 AM MST today. The narrow region of freezing fog coupled with low ceilings as shown on the latest GOES-E nighttime microphysics plus some of the high-res guidance suggests the spread of fog/freezing fog into more of Dawes and Morrill Counties that may warrant extensions later this morning. Current available webcams in the neighboring counties though still show unhindered visibility conditions though patchy fog may linger in some of the lower areas. Concern to watch will be the low elevations of Converse County and Niobrara County with the snow later today.
Expecting quiet weather during the day today, but cloudy and much cooler than yesterday, about a 10-15 degree difference, as the next disturbance begins to work its way into the area. Current QPF estimations are not very high and precip is expected to be mostly snow, with the highest amounts being only 1-2 inches west and southwest of a line from Lexington, NE to Osborne, KS.
The high will get pushed eastward late tonight ahead of an approaching broad low pressure system. With abundant cloud cover over the area, will only see temperatures rise a few degrees today, with highs ranging from the lower 20s east to the lower 30s west. A series of s/w troughs are progged to traverse through the area during this time which will aid in our precip chances.
As for high temperatures today, will vary from near freezing far north to around 50 degrees far south where there will be less cloud cover early on.
Gusts will subside after sunset at most TAF sites, however winds should remain elevated and slowly veer around to the northwest as a cold front approaches the region. A quick moving upper trough currently over AZ will deepen as it moves across the Southern Plains Tuesday. High winds now look likely across the Guadalupe and Delaware Mountains this afternoon and evening as the base of the upper trough moves overhead and higher winds aloft mix to the surface.
305 AM CST Mon Jan 27 2020 Areas of dense freezing fog will continue to reduce visibilities to a quarter mile or less at times, in addition to producing a glaze of ice on roadways, particularly elevated surfaces.
/issued 230 AM EST Mon Jan 27 2020/ A weak trough axis is propagating eastward across the southeast.
Patchy freezing fog is possible in some of the valley areas this morning.
Low pressure will move into eastern Arizona this afternoon with scattered rain and snow showers ending before sunset.
Forecast summary: Mainly cloudy and cooler weather returns to the region for most of the work week, but temperatures look to rebound for the weekend.
Low level flow will transition to more southerly tonight as high pressure advances east of the region. Clouds this morning over southeast Texas and southerly Louisiana along with dew points in the 50s is helping to keep the region a bit warmer.
519 AM EST Mon Jan 27 2020 Under mostly clear skies and light and variable winds in the lower and Middle Keys, but with north winds near 10 mph in the Upper Keys, temperatures range from the mid 50s to the mid 60s in the Upper Keys.
Additional snow amounts today will remain light, with any accumulations approaching an inch likely confined to some of the ridgetops, although lake enhancement may allow for some slight bumps to coverage and amounts north of I-80. Isolated freezing drizzle throughout the day is also possible in the absent of ice crystal in the DGZ and ground temperatures near/below freezing. Will continue to hold HWO for freezing drizzle. The drizzle/freezing drizzle threat may continue into at least tonight as moisture remains shallow, but confidence remains low and will allow the day shift to evaluate this chance.
936 AM EST Mon Jan 27 2020 Upper low level pressure will keep skies mainly cloudy through Tuesday with snow showers possible in the mountains. The weekend may be fair also, but there is a chance that low pressure may affect the region later in the weekend. A short wave trough will pass across the region today keeping skies mostly cloudy. While the main short wave trough moves off to the east tonight and Tuesday, broad and moist cyclonic flow will persist over New England, allowing for clouds to persist. Under this regime southern stream energy will pass well to our south with high pressure building into the Northeast. High temperatures will be around seasonal averages mid week warming to above average by the end of the week as high pressure shifts to our east.
The cloud cover should hold afternoon highs in the mid to upper 60s across the Nature Coast counties, and around 70 to the lower 70s central and south. The higher sustained winds of earlier this morning have diminished so will let the Small Craft headlines for the Tampa Bay waters as well as the near and offshore waters between Englewood and Tarpon Springs out 60nm expire at 9 AM, otherwise the rest of the forecast is in good shape with no other changes planned in the next forecast update around 10 AM.
Removed freezing rain mention as temperatures are remaining above freezing most areas and daytime warming should further erode potential. Temperatures across the region will be a couple of degrees cooler. Drier weather expected this evening but winds will be stronger for gap flow areas as the upstream ridge strengthens surface pressure west of the continental divide. Like the current system the next ridge becomes infused with moisture and tracks into the area later on Tuesday.
Rain has departed to the east, and as the boundary layer mixes out today, the low clouds and drizzle should improve. High pressure in place over the region tonight and some lingering low- level moisture may allow for fog to develop across much of the area.
The only wrinkle in the forecast is a couple slight chances for freezing drizzle and light snow early this morning and late tonight. With low level moisture in place, a surface front moving through early this morning may spark off areas of freezing drizzle or light snow. This will be the best window for any freezing drizzle or light snow and could cause some slick spots on roads.
338 AM CST Mon Jan 27 2020 Currently, the cool high pressure system with stratus entrenched extended from the high center in northern Manitoba with its axis extending into the eastern Dakotas and western Minnesota. At upper levels, a low center over southeastern South Dakota continued moving southeast out of our area with weak ridging over the Front Range.
A quick moving upper trough currently over AZ will deepen as it moves across the Southern Plains Tuesday. High winds now look likely across the Guadalupe and Delaware Mountains this afternoon and evening as the base of the upper trough moves overhead and higher winds aloft mix to the surface.
May see some icy conditions develop though as temperatures will initially be above freezing so wet untreated surfaces will freeze creating slick conditions.
Clouds this morning over southeast Texas and southerly Louisiana along with dew points in the 50s is helping to keep the region a bit warmer.
SREF currently indicates better chances of the lower vsbys centered generally along the I-10 corridor.
524 AM CST Mon Jan 27 2020 Areas of dense freezing fog will continue to reduce visibilities to a quarter mile or less at times, in addition to producing a glaze of ice on roadways, particularly elevated surfaces.
Northwest flow in the mid levels with trof axis dropping south through the Ohio Valley today. Clouds will thicken and lower with the passage of this trof.
Visibility has been the lowest in the Missoula and Bitterroot valleys, so a Dense Fog Advisory has been issued. Snow has lingered in Lemhi County, Idaho and southwest Montana, and a few showers will linger elsewhere, causing snow, and the potential for freezing rain or drizzle. Mountain snow, and valley mixed precipitation will become widespread overnight tonight as a warm front brings increasing moisture. The higher terrain of central Idaho and along the Idaho/western Montana border (including Lookout and Lolo Passes) remain the most favored locations for 6 to 12 inches of new snow by Tuesday night. Valley locations will have rising snow levels during Tuesday, but snow levels will lower with cold front passage during Tuesday evening, so light valley accumulations are possible for Tuesday night.
Around sunrise, the cold front currently over Nebraska will begin to move into the area, ushering in north winds and low stratus for the day. Frontogenesis to the north of this low will cause a large area of precipitation to develop Monday night across western Kansas and Oklahoma, spreading east on Tuesday. Snow will spread east across much of the area during the day on Tuesday, with an additional evening round of light snow possible across northeast portions of the area as a secondary vorticity maximum drops southwest into the upper trough.
However, the clouds should break enough this afternoon for temperatures to still warm into the lower to mid 60s.
The pattern for the week is dominated by upper level ridging, with a couple of week troughs coming in to bring slightly cooler--but still seasonably warm--temperatures during the work week.
High pressure aloft will move into Utah behind the upper level trough exiting the area this morning.
648 AM EST Mon Jan 27 2020 Upper low level pressure will keep skies mainly cloudy through Tuesday with snow showers possible in the mountains. The weekend may be fair also, but there is a chance that low pressure may affect the region later in the weekend. A short wave trough will pass across the region today keeping skies mostly cloudy. While the main short wave trough moves off to the east tonight and Tuesday, broad and moist cyclonic flow will persist over New England, allowing for clouds to persist. Under this regime southern stream energy will pass well to our south with high pressure building into the Northeast. High temperatures will be around seasonal averages mid week warming to above average by the end of the week as high pressure shifts to our east.
644 AM EST Mon Jan 27 2020 Occasional light snow and flurries, possibly mixed with some patchy freezing drizzle is possible into early this morning.
There could be some spots where freezing drizzle mix in. Slight chance for some freezing drizzle to mix in. Watching a slight chance for freezing drizzle and light snow between 06Z and 12Z Tuesday. The only wrinkle in the forecast is a couple slight chances for freezing drizzle and light snow early this morning and late tonight. With low level moisture in place, a surface front moving through early this morning may spark off areas of freezing drizzle or light snow. This will be the best window for any freezing drizzle or light snow and could cause some slick spots on roads.
Dry weather is expected for much of the week with weak high pressure in place. An upper level low pressure system will be approaching the area this weekend with a mixture of rain and snow possible.
Upper trough and associated light rain showers will move east of the region this evening, with high pressure building to the northwest through the night.
Temperatures were on track and provided there is some insolation this afternoon, temperatures are expected to top out slightly warmer than normal. Rain has departed to the east, and as the boundary layer mixes out today, the low clouds and drizzle should improve. High pressure in place over the region tonight and some lingering low- level moisture may allow for fog to develop across much of the area.
257 PM CST Mon Jan 27 2020 An upper level trough is bringing strong winds to the Guadalupe Mountains this afternoon that will continue for a few more hours before diminishing. This trough could also bring a few high based showers to southeastern New Mexico before moving east overnight. A cold front moves through the region tonight bringing windy conditions that will border on advisory level Tuesday for the Permian Basin.
158 PM MST Mon Jan 27 2020 Current surface map places warm front over eastern Montana into eastern Wyoming. Snow associated with upper trof is spreading into northeast Wyoming.
1125 AM CST Mon Jan 27 2020 Areas of dense freezing fog will continue to reduce visibilities to a quarter mile or less at times, in addition to producing a glaze of ice on roadways, particularly elevated surfaces.
Cold front is currently bisecting the cwa with cloudy skies, fog and a few showers over our eastern counties, but clearing skies and northwest winds over our west.
Temperatures have warmed nicely, with 2 pm temperatures in the lower to mid 50s. Clear skies will persist through the overnight hours, allowing temperatures to fall into the lower to mid 30s by daybreak. An upper ridge over the eastern Plains will build eastward on Tuesday, as a trough moves east of the Rockies. This ridge will generally break down as it nears the TN Valley, though weak height rises will combine with mostly clear skies to help temps warm into the mid to upper 50s. As the trough progresses eastward, a low will cut off over the TX Panhandle as the subtropical jet strengthens. As this low/trough propagates eastward and into the Mississippi Valley, southwesterly flow will result in moisture return over the region with clouds increasing Tuesday afternoon and into Tuesday night.
Late tonight into Tuesday morning, lift in the low levels along a lake convergence zone should increase the potential for light snow showers, though amounts will be light as cloud tops will be capped at 4000 ft / -10 C.
A cold front extending from the Appalachians through Middle TN is pushing to the southeast and is expected to progress through our region later this afternoon. Drier air pushing in ahead of the cold front will allow skies to gradually scatter late this morning into early this afternoon. Clear skies combined with a later arrival time of the weak cold front will result in high temperatures today reaching the mid 50s. Should the cold front continue to slow, temperatures may even reach the upper 50s in some places.
increasing low level moisture could keep the low ceilings around longer than expected. then cooler conditions will be possible.
Building high pressure will return dry weather and seasonable temperature by mid-week. Precipitation type will be dictated by surface temperature, and the best chance for freezing drizzle should be confined to areas north of the I-80 corridor and in the eastern ridges through tonight. Areas elsewhere, including the Pittsburgh metro area, should observe drizzle as surface temperature hovers above freezing through the remainder of this afternoon. Similarly, upslope in the ridges should yield enough ascent to maintain areas of freezing drizzle overnight. Such shallow moisture evident in forecast soundings may support the development of areas of drizzle / freezing drizzle again Tuesday but have opted to allow later shifts to refine precipitation type with updated guidance.
Road temps are running 4-5F warmer than air temps so only wet conditions should result. Thus will continue the small potential for drizzle/freezing drizzle and very light snow for tnt-Tue AM. Sct flurries and very light patchy drizzle/freezing drizzle may occur at times. Light wnwly winds will continue over Lake MI through Tue, then veer to enely for Tue nt-Wed as a broad area of high pressure moves ewd across srn Canada.
Radar and surface observations showing a few flurries and some drizzle or freezing drizzle across portions of the area as well. Although moisture remains at low levels, lack of deeper moisture and weak forcing will limit potential for light snow and more widespread areas of drizzle and freezing drizzle. With the clouds not budging tonight, leaned heavily toward the warmer guidance for low temps, which keeps most spots in the 20s.
The morning KEY sounding depicts a substantial amount of dry air in the lower levels of the atmosphere (below 700 mb) with a mostly saturated troposphere in the mid to upper levels. The main story today will be a gradual moistening of the low-levels and subsequent destabilization facilitated by both an ample amount of moisture transport from the southwest and evaporational cooling from stratiform precipitation aloft (in association with lift from the right entrance region of a jet streak). From the synopsis: A small low pressure center in the central Gulf of Mexico will move east-southeastward this afternoon, dragging a trough through our region tonight and Tuesday.
The low clouds stuck along these river valleys are showing little erosion as of 11AM and will likely hold well into the afternoon hours. A strong and very moist warm front moves in this evening and overnight bringing light to moderate precipitation. Winter Weather Advisory from 4 PM this afternoon to 5 AM PST Tuesday for the higher elevations around wenatchee and chelan for Waterville Plateau-Wenatchee Area.
Also watching some speckles of very light freezing drizzle working westward toward the Mississippi River. Per guidance trends, not as much of a freezing drizzle signal as existed this time yesterday as that wave passes, though still some hint for sufficient moisture depth to near 1. Temperatures look a little warmer today as shallow warm advection wraps in from the east, giving way to another slight cooling trend Tue-Wed, though still well above normal for the time of year. That setup will favor broad anomalous upper ridging developing over much of the western states, extending eastward through the Plains and Upper Midwest briefly through the weekend (per current trends, of course). In addition, some light freezing drizzle is expected again late tonight into Tuesday morning, mainly east of the Mississippi River.
Modest cold advection with this wave may be just enough to steepen up the low level lapse rates and increase cloud depths to generate flurries/very light snow showers. 850 MB temps around -10 C looks to be sufficiently cold enough for ice nuclei, so the prospects for freezing drizzle appears to be very low.
Flurries or patchy freezing drizzle is likely tonight, mainly on the ridge tops along and to the west of Route 219.
255 PM CST Mon Jan 27 2020 20Z water vapor imagery shows a upper trough over the Rockies. Surface observations indicate high pressure centered over eastern ND with the ridge axis extending through the central plains. An area of low pressure was slowly deepening in the lee of the southern Rockies. Eventually forecast soundings become saturated as the upper level trough axis passes overhead late Tuesday afternoon and Tuesday night. There looks to be some modest frontogenesis with the trough axis and better vertical motion for light snow. Models show the low clouds hanging on strong through Tuesday night. So have lows tonight and Tuesday night in the mid and upper 20s with Highs on Tuesday in the lower 30s.
Cold front is currently bisecting the cwa with cloudy skies, fog and a few showers over our eastern counties, but clearing skies and northwest winds over our west. A cold front has made it through most of Middle Tennessee, with earlier light rain already gone and only some patchy fog and low clouds along the Cumberland Plateau and areas just west.
This cloud cover would likely remain in place through the day on Tuesday and keep high temperatures down considerably from model guidance, and have gone much cooler than the GFS/NBM and closer to the NAM for highs.
352 PM EST Mon Jan 27 2020 Chances for a wintry mix of snow, drizzle, and freezing drizzle is possible overnight into Tuesday, with the best chances near Lake Michigan and west of interstate 69.
256 PM CST Mon Jan 27 2020 A mid-level trough of low pressure/weak pv-advection drops south out of Canada into the region tonight. Patchy light freezing drizzle or snow grains is anticipated as a result of this lift. Will have to keep an eye on how widespread/intense the freezing drizzle will be -possibly leading to some slick roadways. The mid-level trough/lift moves southeast of the area by daybreak Tuesday which should shut down freezing drizzle/light snow threat. For the rest of the day a ridge of high pressure will build into the region. Short wave troughs will continue to come onshore from the northern Pacific, top the weak ridging over the Rockies and then cross the central part of the country.
Highs will reach well into the 50s as weak high pressure nudges into the area. /issued 340 AM CST Mon Jan 27 2020/ Temperatures and dew points are both in the low to middle 40s across most of the Midsouth under clearing skies.
233 PM EST Mon Jan 27 2020 Low pressure passes south of the area early this morning.
High pressure aloft will move into Utah and southwest Wyoming behind the upper level trough exiting the area this morning.
934 AM MST Mon Jan 27 2020 Pacific cold front moving across the area this morning. As this precipitation spreads eastward it will encounter some pockets of sub-freezing air in the eastern river valleys that could result in locally slick travel conditions. This threat will diminish as the morning goes on and road temperatures warm above freezing. Removed freezing rain mention as temperatures are remaining above freezing most areas and daytime warming should further erode potential. Temperatures across the region will be a couple of degrees cooler. Drier weather expected this evening but winds will be stronger for gap flow areas as the upstream ridge strengthens surface pressure west of the continental divide. Like the current system the next ridge becomes infused with moisture and tracks into the area later on Tuesday.
Model guidance seems to be in reasonable agreement in regards to the path of this system however surface temperatures are a bit in flux depending on how quickly the cold front can push through the area. While there is the potential for some wet snow flakes to fall during the early morning hours Tuesday expect surface temps to remain at or above freezing so accumulations should be non existent. As the cold front moves through, northerly winds will ramp up into the 25-30 mph range behind it and remain elevated through at least early Tuesday afternoon.
Temperatures are holding in the teens and 20s, with readings a bit closer to the freezing mark throughout and west of the Missouri River valley this afternoon. Guidance depicts the warm front aiding forcing for this banded light snow event may work for enough east into the CWA to see the edge of the stratus field erode/dissipate across the west river zones of this CWA Tuesday afternoon. Likewise, on Tuesday, the low level waa may help nudge the mercury up some across the Missouri River valley and points west where there could be some sunshine.