Aikyam-Lab/Synoptic-Bench huggingface dataset:
638 AM EST Fri Feb 12 2021 High pressure well northwest of the Ohio Valley will keep a cold, northerly flow over the region.
328 AM CST Fri Feb 12 2021 Early this Friday morning, temperatures were mainly in the 27-32 range with patchy freezing fog/drizzle. This will maintain our current setup of cold temperatures at the surface with warmer air several thousand feet up above the surface. We think freezing rain will be the result, but the big question is how much moisture and precipitation will occur.
Based on the hour precipitation rates, along with gauge data, the Sierra Nevada region is observing the higher rates. Based on the orientation of the channeled flow, will maintain the high wind for areas around Kern County that favor strong winds (mainly the mountains and desert).
Band of weak lift over the southern half of southern Montana and northern Wyoming is producing light snow and keeping temperatures warmer closer to -10F. Despite clear skies daytime temps will not rise above -5F in the lower elevations with wind chills keeping readings around -20 to -30F.
355 AM MST Fri Feb 12 2021 Broad cyclonic flow aloft continues this morning as deep/cold upper low persists across the central Canadian prairies. Embedded perturbations continue to stream eastward along the southern periphery of the low.
With a 1040 mb high pressure over head, max temps today will struggle to reach the single digits below zero.
904 AM EST Fri Feb 12 2021 High pressure well northwest of the Ohio Valley will keep a cold, northerly flow over the region.
There is a small window until 12/15Z that some light freezing drizzle may occur at KAEX. A strong cold front has moved into the gulf over the past day with an Arctic air mass spilling in. Moderate rain with embedded thunderstorms is currently moving east across the lower Atchafalaya Basin in response to a short wave aloft. Cold air advection is still ongoing as the front slowly sinks south and temperatures have fallen to near freezing from the Toledo Bend through Central Louisiana. Temperatures will fall to around freezing across interior southeast Texas and Central Louisiana and perhaps down to around Hwy 190.
936 AM EST Fri Feb 12 2021 Snow showers dwindle along the south of Lake Ontario today as high pressure builds back across the region. High pressure departs tonight as a weak system moves into the region Saturday through Saturday night with widespread light snow.
Radar continues to show rain and snow impacting portions of interior northern California this early Friday morning as an upper level low pushes southeast across the region.
720 AM EST Fri Feb 12 2021 Snow showers dwindle south of Lake Ontario today as high pressure build back in over the region. High pressure departs tonight as a weak system moves into the region Saturday through Saturday night with widespread light snow.
Looks like temperatures will remain below freezing for the vast majority of the area.
Surface analysis this morning places a quasi- stationary boundary located over Northern Georgia and South Carolina and a cold front from Southern Alabama back into the Northern Gulf of Mexico.
959 AM EST Fri Feb 12 2021 High pressure will remain in control through most of Saturday.
307 AM MST Fri Feb 12 2021 An Arctic cold front still remains along the Continental Divide trying to slowly push southwest into Sweetwater County early this morning.
A low pressure system will bring a chance of light rain and high elevation snow showers today.
405 AM EST Fri Feb 12 2021 High pressure well northwest of the Ohio Valley will keep a cold, northerly flow over the region.
1225 PM EST Fri Feb 12 2021 High pressure well northwest of the Ohio Valley will keep a cold, northerly flow over the region.
Elsewhere, a trace to one-half inch of snow is possible, with the lowest amounts south of Interstate 70.
Weak ridging has moved into the area which is bringing us a relative break in the action which is being supported by radar which is showing little to nothing over the area. The general consensus among the operational models and short range high resulution models is for precipitation to gradually increase, first along the coast and Douglas County around midday, then early afternoon along the Cascades as a warm front approaches. Later this evening and tonight precipitation will chances will increase just about everywhere, but especially west of the Cascades as a cold front approaches.
141 PM MST Fri Feb 12 2021 The upper level trough will move drop into central Arizona by 00z and continue to dig further to the southeast overnight. No changes to the Winter Weather Advisory at this time, with the highest amounts expected over the Park Range. On Saturday, the next Pacific Northwest trough will make its way into northern UT by 00z.
Thermal ridging should then diminish any lingering precipitation chances by early eve. Upper flow is forecast to back to the southwest in response to a digging trough over the central CONUS. At the moment, frontal orientation and warm advection above the boundary layer indicate mixed precip for the area with some possible freezing rain south and east of Pittsburgh, including portions of SE Ohio.
944 AM MST Fri Feb 12 2021 Broad cyclonic flow aloft continues this morning as deep/cold upper low persists across the central Canadian prairies. Embedded perturbations continue to stream eastward along the southern periphery of the low.
812 AM PST Fri Feb 12 2021 A compact low pressure system moving southward through the area today will bring cooling with gusty west to northwest winds in the mountains and deserts and with scattered mostly light showers from the coast into the mountains. The next low pressure system moving southeastward across the area will bring strong gusty west winds for the mountains and deserts for Saturday into Saturday evening with a slight chance of light showers for the mountains in the late afternoon and early evening.
Extensive cloud cover and a cooler trend in temperatures this morning allowed for a very slight reduction in high temperatures for the day. Otherwise, the main question tonight into tomorrow will be if the combination of moisture and sub-freezing surface temperatures in the northern periphery of the area will be sufficient for additional products. CDG Chattanooga Airport, TN 45 41 47 38 47 / 20 80 80 20 30 Knoxville McGhee Tyson Airport, TN 43 38 45 37 46 / 20 60 70 40 30 Oak Ridge, TN 43 37 44 36 45 / 10 40 70 30 30 Tri Cities Airport, TN 44 38 47 38 48 / 40 30 60 40 30.
That combined with some light northwest winds, the highest our winds chills will get today is -10 to -15.
Temperatures have thus been steady or falling across most of north and eastern Georgia today as this wedge of cooler air builds in at the surface. As far as temperatures are concerned, the cooler side of guidance was favored tonight into tomorrow given the nature of the wedge with the NAM more heavily favored during the overnight based on temperature trends.
Models have trended a bit warmer than last night, but models were also too warm by about 5 to 8 degrees compared to last night's lows. Therefore, went toward the lower end of model guidance, especially across the north.
NBM shows a chance of freezing rain at Burns/OR overnight with above-freezing moist air moving over sub-freezing surface air.
Deep/cold upper level low centered over southern Manitoba through tonight will gradually shift east while filling this weekend.
In the lower levels, much of the area remains in northerly flow at the surface in the wake a surface cold front that remains parked off the coast through the period. An area of weak low pressure begins to develop along the stalled front off the coast south of the region through tonight into Saturday morning. Surface pressure troughing extending northwest from this low, in addition to synoptic ascent aloft, will help provide a focus for higher rain chances on Saturday with the highest PoP chances southeast of the I- 65 corridor. IFR/LIFR CIGs continue to overspread the region and are expected to prevail through the period as a cold front remains stalled off the coast.
IFR/LIFR CIGs continue to overspread the region and are expected to prevail through the period as a cold front remains stalled off the coast.
A closed low continues to spin over southern Saskatchewan, and will gradually meander towards the Manitoba/Ontario border by late tonight.
Cold upper low continues to reside over southern MB, but will slowly make progress eastward through the weekend. Wind chills will continue to be dangerously cold at night, and a little warmer during the day.
Not unlike last night, we cannot rule out entirely a flurry or trace freezing drizzle given some PVA will be moving across the area.
The upper level low is currently located west of Las Vegas and will continue to shift southeastward through the afternoon. Precipitation observations through about 9 AM this morning show the highest amounts in areas that favor upslope southwesterly flow, with the greatest snow totals across locations like Snowbasin and the northern Wasatch Mountains. Additionally, the surface/mid-level boundary associated with the previously mentioned upper level low is supporting the develop of relatively widespread precipitation across southern Utah.
/issued 524 AM CST Fri Feb 12 2021/ Surface analysis this morning places a quasi- stationary boundary located over Northern Georgia and South Carolina and a cold front from Southern Alabama back into the Northern Gulf of Mexico.
Temperatures did rebound as promised and across the island chain current temps are in the lower 80s and dew points are in the lower 70s. A deep layer ridge remains anchored between Bermuda and the Greater Antilles and extends westward into the central Gulf of Mexico. Meanwhile, to our west and aloft, there is a trough digging across the central U.
1046 AM MST Fri Feb 12 2021 An Arctic cold front still remains along the Continental Divide trying to slowly push southwest into Sweetwater County early this morning.
315 PM CST Fri Feb 12 2021 WV imagery shows the next upper trough entering SW AZ, and this should dig to NE Sonora by 06Z Saturday. Closer to home, cold stratus/FZFG remains banked up against the higher terrain, keeping roads icy. After 06Z, large-scale ascent ahead of the incoming trough will develop precip centered over the Davis Mtns/Stockton Plateau, and spreading north and east Saturday morning as the trough moves through.
High pressure building in across the area will quickly clear skies out Saturday night, allowing low temperatures to plummet to around 20 below across the north, the teens below zero across central, and around 10 below across east- central and northeast Wisconsin.
There will be a short break during the day Saturday as we await the main trough moving in from the 4 corners region.
Any accumulations will be light, but overpasses and bridges could become slick.
Been getting reports of patchy freezing drizzle/fog in several areas, and even a few snow flakes across the extreme north. Looking at the latest temp structure, this PCPN will likely be freezing rain with good warm nose aloft. Freezing fog CSV thru 13/16Z. Freezing drizzle CSV developing 03/06Z will transition to potentially light snow 13/13Z-13/16Z. There is still some potential for mainly freezing precipitation at these sites, but not enough of a chance to warrant mention in a prevailing FM group.
Highs are mainly in the lower to mid 20s across the entire CWA, with wind chills in the teens. Otherwise, we've seen a lull in the freezing drizzle/sleet this afternoon. This would again be in the form of light freezing rain or drizzle with some sleet pellets mixed in as well. Any additional freezing rain or drizzle would obviously aggravate the poor driving conditions across the area. Afternoon highs tomorrow will remain below freezing, mainly in the 20s.
Snow is expected to ease slightly this afternoon, but will once again intensify tonight through Saturday for north central Idaho, including the Camas Prairie and the Highway 95 corridor.
Weak pressure rises could allow modest northerly winds to persist thru the night across the wrn SD plains, producing slightly cooler wind chills in some areas.
POPs ramp up 06Z 02/14 and with low temps north of the I-10 corridor falling to or below freezing, a chance of sleet and freezing rain are possible. The highest accumulation amounts for snow are expected 12Z 02/15.
The next low pressure system moving southeastward across the area will bring strong gusty west winds for the mountains and deserts Saturday.
Upper flow is forecast to back to the southwest in response to a digging trough over the central CONUS. At the moment, frontal orientation and warm advection above the boundary layer indicate mixed precip for the area with some possible freezing rain south and east of Pittsburgh, including portions of SE Ohio.
A closed upper level low is currently sitting over southern Manitoba, and it will slowly shift eastward through the weekend.
A couple of notable troughs embedded in this flow will influence our weather during the short term period. Temperatures will be important during the event, with readings expected to be below freezing much of the time. An SPS will be issued to highlight the potential for freezing drizzle. It's uncertain if there will be much impact, being that the precip totals will generally be very light, and most roadways are probably already treated due to the recent freezing rain.
This upper level trough is not expected to be all that robust over the plains. But the factors that could make this a significant event are the low liquid water equivalents (.
This will maintain our current setup of cold temperatures at/near surface with warmer air several thousand feet up above the surface. Highlights of that special weather statement issuance include that after midnight tonight, freezing drizzle will be possible mainly across locations around and east of I-65 Corridor with the possiblity of freezing drizzle lasting until Saturday mid morning hours. Patchy freezing fog could also develop late tonight and last until mid morning hours on Saturday mainly across Cumberland Plateau Region.
Based on model soundings, the cold air is rather shallow, so thinking the precip type will likely be freezing rain. Ice accumulations was introduced into the forecast but still really want to stress that there is a lot of uncertainty and depending on how far south the cold goes, areas could be impacted with at least a glazing of ice, or puddles freezing. Strong high pressure with arctic cold mass over the midwest draping down southward will bring quite a strong cold snap for the area with freezes likely across most of the area with some hard freezes possible.
A boundary that sets up first as a col then as a weak trough by morning is depicted in the GFS. The low level inversion north of the boundary should also help the high dewpoint air and cool water to form fog.
1242 AM EST Sat Feb 13 2021 A wedge of high pressure will persist inland through the weekend, while waves of low pressure pass along a stalled front lingering nearby.
107 AM EST Sat Feb 13 2021 Aviation - Brief burst of snow with localized impacts this evening - A period of light snow Saturday will coat the roads - Storm system could generate additional snow Mon into Tue The remnants of earlier lake effect that progressed into Western Lower Michigan has either dissipated or moved back out over Lake Michigan in light easterly flow in the lowest 5k feet. lake effect Sunday The moisture deepens up considerably on Saturday as the next wave of low pressure moves in. Colder air advects in from the northwest on the backside of the departing low pressure system The moisture is shown to become quite shallow.
While model soundings show the depth of this near surface layer trending a bit cooler and expanding modestly in depth Saturday night, no precipitation is expected with these conditions. Have updated lows tonight about 2 degrees lower based on the lowest trends which now range from the upper 30s over interior southeast Mississippi and interior southwest Alabama to the lower 50s over the easternmost portion.
There will be a short break during the day Saturday as we await the main trough moving in from the 4 corners region. Saturday should be slightly warmer.
Weak high pressure will quickly move across Arizona tonight. A quick moving weak ridge of high pressure will move across the state tonight with just some high thin clouds. A weak, fast-moving trough traversing northern Arizona today is bringing some light rain and high elevation snow shower activity to the area.
Saturday night into Sunday morning has a little more uncertainty as the high surface pressure appears to slightly deepen just before heading east Sunday afternoon.
Taking a quick look at water vapor imagery depicts a mid/upper lvl perturbation lifting NE into the lower Mississippi River Valley tonight. Additionally, temperatures have remained nearly steady-state across portions of the Cumberland Plateau, near or below freezing. This has caused light freezing drizzle and freezing fog in these locations. Most locations should stay above freezing across the area tonight, but those locations mentioned above may continue to see freezing drizzle and fog tonight. CDG Chattanooga Airport, TN 45 39 47 38 47 / 60 20 30 40 50 Knoxville McGhee Tyson Airport, TN 44 37 44 37 45 / 70 30 40 50 40 Oak Ridge, TN 43 36 43 35 42 / 60 30 30 50 30 Tri Cities Airport, TN 46 38 46 38 48 / 80 30 40 30 30 TN.
Upper flow is backing to the southwest in response to a digging trough over the central CONUS. Light freezing rain or drizzle is also possible though given the moist sfc layer, but confidence in problematic ice accumulation is low at moment, so no advisory will be issued for now.
1049 PM EST Fri Feb 12 2021 Update - Brief burst of snow with localized impacts this evening - A period of light snow Saturday will coat the roads - Storm system could generate additional snow Mon into Tue The remnants of earlier lake effect that progressed into Western Lower Michigan has either dissipated or moved back out over Lake Michigan in light easterly flow in the lowest 5k feet. lake effect Sunday The moisture deepens up considerably on Saturday as the next wave of low pressure moves in. Colder air advects in from the northwest on the backside of the departing low pressure system The moisture is shown to become quite shallow.
As temperatures have now fallen below freezing at Monroe County Airport, freezing rain is likely the main precipitation type. This area of freezing rain isn't currently captured well by the CAMS, but based on current trends the event could last a few hours or more. Light ice accumulations are possible, especially on elevated surfaces such as bridges and overpasses. Any accumulations will be light, but overpasses and bridges could become slick. By Sunday afternoon, light precipitation ahead of a potent upper trof will begin to spread into Eastern Arkansas. Precipitation would likely be in the form of freezing rain or sleet as a warm layer just above the surface is apparent in model soundings.
325 AM EST Sat Feb 13 2021 A warm front lifting north today brings some light snow over Central NY and mixed precipitation to NE PA late this afternoon through the overnight hours. A warm front lifts north into our region late today into the overnight hours providing some weak isentropic lift with QPF amounts amounting to a few hundredths of an inch. Right now NE PA will have the warmest clouds but still below freezing through the column with patchy freezing drizzle mixing with the light snow grains at times especially across some of the higher terrain.
Have added low chance of light freezing rain to this area overnight into early Saturday morning, however the minor icing/glazing should be limited to mostly elevated surfaces. Based on model soundings, the cold air is rather shallow, so thinking the precip type will likely be freezing rain. Ice accumulations was introduced into the forecast but still really want to stress that there is a lot of uncertainty and depending on how far south the cold goes, areas could be impacted with at least a glazing of ice, or puddles freezing. Strong high pressure with arctic cold mass over the midwest draping down southward will bring quite a strong cold snap for the area with freezes likely across most of the area with some hard freezes possible.
Freezing drizzle around the area now is light icing some cars, etc. But this pcpn coming up a bit more apt to cause bigger issue on roads, bridges. Thus put out an Advisory for freezing rain through the morning for a light glazeacross the south. Light freezing pcpn will also affect CSV and most likely BNA/MQY on Saturday as well.
For Saturday, upper flow is forecast to back to the southwest in response to a digging trough over the central CONUS. At the moment, frontal orientation and warm advection above the boundary layer indicate mixed precip for the area with some possible freezing rain south and east of Pittsburgh, including portions of SE Ohio.
A closed low continues to spin over southern Saskatchewan, and will gradually meander towards the Manitoba/Ontario border by late tonight. The coldest air aloft will be exiting the region by Sunday morning, but arctic high pressure at the surface will be present.
Taking a quick look at water vapor imagery depicts a mid/upper lvl perturbation lifting NE into the lower Mississippi River Valley tonight. Additionally, temperatures have remained nearly steady-state across portions of the Cumberland Plateau, near or below freezing. This has caused light freezing drizzle and freezing fog in these locations. Most locations should stay above freezing across the area tonight, but those locations mentioned above may continue to see freezing drizzle and fog tonight. Diegan Chattanooga Airport, TN 38 45 38 47 38 / 60 70 30 30 40 Knoxville McGhee Tyson Airport, TN 35 44 37 44 37 / 50 60 30 40 50 Oak Ridge, TN 35 43 36 43 35 / 50 60 30 30 50 Tri Cities Airport, TN 38 46 38 46 38 / 60 70 50 40 30 TN.
This split also captures the higher rain chances through Saturday morning over the eastern Straits, along with the potential for isolated thunder.
Another round of snow is set to move in from the west late this evening through Sunday, mainly affecting the southern portion of the CWA as mid-level troughing begins digging south and east from the Intermountain West.
339 AM MST Sat Feb 13 2021 Cold upper low continues to slowly meander south and east across southern Canada. Broadly cyclonic flow persists across the upper half of the US with embedded perturbations streaming along the southern periphery of this low.
Freezing drizzle the result, keeping roadways slick and hazardous. As the wave passes the area today, some patchy light freezing rain, more freezing drizzle, and some sleet will likely continue.
Currently, Arctic high pressure is situated over southern Saskatchewan and Manitoba, with a closed upper low over southern Manitoba. This high will slowly drift southwest today and will be situated over western and central North Dakota by 12 UTC Sunday. Even though the core of the coldest air aloft is moving to the east, it's still just a few degrees warmer than it is this morning. Would like to see the center of the high a little farther to the southeast for a record setting low at Bismarck.
444 AM EST Sat Feb 13 2021 The weather pattern across the Florida Keys remains stuck between a high pressure system over the western Atlantic and a weak stationary front over the central Gulf of Mexico. Temperatures and dew points across the island communities are in the mid 70s, which is much warmer than average for mid February. Scattered showers are in the forecast for the Middle and Upper Keys for this morning, and only a slight chance of rain for the Lower Keys.
Drier sir in the lower levels will limit snow across northern portions of the state with little or no accumulation forecast there.
330 AM MST Sat Feb 13 2021 Latest WV/IR imagery showed the polar vortex over south-central Canada with its associated trough extending south through the Plains. A weakening upper low was moving east over far northern Mexico. With snow the primary hazard to travel, opted not to issue Wind Chill Advisories and mention the lowest wind chill temperatures in the Winter Weather Advisory products.