Aikyam-Lab/Synoptic-Bench huggingface dataset:
Above-freezing surface temperatures through the evening and sufficiently warm ground temperatures should negate prospects for snow accumulation. As drier air aloft overspreads the area through the evening, precipitation should wane while temperatures fall into the lower 30s by late tonight. There is some indication that elevated warm advection, related to the amplifying trough, could increase tonight and support patchy drizzle. While a few spots of near-freezing surface temperatures could conditionally support freezing drizzle, forecast soundings suggest very shallow low-cloud depths -- casting considerable doubt on any precipitation opportunities. Moreover, antecedent above-freezing surface temperatures would limit any possible ice accumulation. As such, drizzle/freezing-drizzle mention has not been included in the forecast at this time.
427 PM EDT Tue Oct 31 2017 High pressure through late tonight. Moisture will quickly increase from the southwest, aided by developing llj, as upper trough deepens across central U. With warm moist air aloft, and drier cooler air near the surface, precipitation could start out as a wintry mix across parts of southeast Ohio. Temps will continue to warm nicely tomorrow across the region as low pressure across the plains lifts northeast, with all areas changing over to rain shortly after 12Z. Southwest flow continues to stream warm, moist air into the region with 850 temps reaching into the low teens (C) by the end of the period.
Low pressure starts to move into the region later this week, with rain at times mainly Thu through Sat. Expect a cooler and showery weekend, with snow levels between 2000 to 3000 feet.
An upper low has moved south of the Medford CWA, and the offshore ridge remains in place, thus low level flow is primarily easterly and will remain so throughout the day. Winds will be strong over the ridges, particularly the Coast Range and Siskiyous. The upper level ridge will remain offshore, but it will weaken Wednesday into the weekend and an upper level trough will dig along the west coast.
256 PM EDT Tue Oct 31 2017 High pressure will generally clear skies to the south of Lake Ontario tonight, with just a few showers lingering over north central New York this evening.
241 PM CDT Tue Oct 31 2017 High pressure at the surface promoting a beautiful All Hallows Eve, with a sunny sky and temperatures in the low to mid 60s. NNE winds have helped to keep temperatures in check somewhat today, but this will change heading into the overnight hours as winds veer back to the SE and eventually the SW by daybreak as a deepening broad upper trough amplifies over the Southern Plains into the Mississippi Valley. Additionally, cannot rule out a few very light showers overspreading the region underneath this low canopy of clouds after 06z, and have an isolated to widely scattered shower mention between 06-12z, generally west of I-65. Pattern change will take effect beginning Wednesday as the aforementioned upper-level trough will slowly move east into the Mississippi Valley.
isolated to scattered showers and isolated thunderstorms will develop across the lower TX coast through the rest of the afternoon into this evening. Otherwise, much warmer and rather tranquil for the most part overnight. This trough should help bring a weak cold front down into deep south Texas later today or tonight. Exactly how far south it moves is still questionable at least before it washes out or the remnants are swallowed up by the coastal trough. Out west we may dry out a little bit as dew points drop into the 50s behind the front, however, cloud cover and maybe some light shower activity/drizzle will be possible as the coastal trough remains over our area. Wednesday's forecast appears to be a little more uncertain all around depending on what exactly happens with the aforementioned trough.
306 PM MDT Tue Oct 31 2017 Upper level analysis has weak ridging off the West Coast with broad trof across the central CONUS. At the surface, high pressure has shifted into the mid-Mississippi valley with low pressure developing across north-central Montana. A cold front will arrive early Wednesday and move southeast across the CWA during the day. Snowfall will mostly be limited to the higher elevations of northeast WY, the Black Hills, and far northwest SD. The higher elevations of the northern Black Hills and WY Black Hills will likely see an inch or two of snowfall later tonight into Wednesday morning.
High pressure over the area today will result in dry, cool conditions. However, a cold front that passed through the area yesterday evening has ushered in a chilly airmass. With sfc air temps and road temps above freezing, no impacts are expected. Low temps tonight should range through the 30s with the low actually being reached before precip arrival and temps slightly warming toward sunrise. The boundary associated with this system will lift north late in the day as a warm front allowing high temps in the 50s to around 60 to occur toward evening.
Soundings indicate the cold layer is deep enough to produce a mix of light rain and light snow over our southeast counties, but it will initially encounter a very dry air mass, thus the low chance POPs (20-30s) will continue in the southeast for later tonight. An active weather pattern seen during this period with models as the upper pattern over the lower 48 transitions back to a west to southwest flow.
254 PM EDT Tue Oct 31 2017 A weak dry cold front will move through from the north this evening and tonight.
A strong cold front is on track to move across the area this morning.
Increasing ridging and a bit of a downslope component off the ridges will support a nice warmup, with many afternoon readings in the 60s south of I-80. Upslope flow may also allow for light rain along east-facing ridges, with a relative PoP minimum in the immediate downslope region. The upper ridge begins to edge eastward Thursday night in response to digging energy into the lower Mississippi Valley. A wave riding up the back of the ridge will pass to the east of Pittsburgh.
The cold front was moving into central Iowa per latest surface analysis. No changes in the general thinking of precipitation types, with a warm layer around 850 mb favoring a period of freezing rain and sleet behind the front. First, forecast soundings hint at potential for some light freezing drizzle to linger for a few hours after frontal passage.
Fog could become locally dense at times before a warm front moves in from the south and/or a cold front sweeps in from the west. Southeast MN and northeast IA will have the higher impacts. Cold air returns for the upcoming weekend, post the departing cold front/storm system, and looks to hang around for the early part of the new work week. Conditions should improve to MVFR late Thursday afternoon into Thursday evening as high pressure builds in from the west.
As a result of the high winds, did issue a high wind warning earlier. It will be much colder across the eastern counties, under the cold high pressure center and associated negative 850-hPa temperatures.
60 inches, which would lead to an area of 5 to 8 inches of snow (given stronger winds snow ratios should be toward the lower end of the spectrum). High pressure overhead Fri night will offer optimum radiative cooling conditions and resultant low temps colder than 20 below throughout the forecast area. Some warm air advection Sun will allow for daytime highs edging over the zero degree mark as a trough swings down within the NW flow aloft. This will be followed by a second instance of potential snowfall for Sun, associated with the previously mentioned upper trough and modest warm air advection. By Wed western ridging will edge closer to our area, bumping temps up toward or beyond seasonal expectations.
Will continue highlights for the interior mountain zones of western Colorado with the main activity pushing southeast across the region behind the cold front. Then a ridge will build over the Great Basin and spread drier air in from the west.
A deep H5 trough over the central U. and a strong high pressure ridge off of the Carolina coast will continue to provide breezy southerly winds drawing up a warm and humid air mass from the Gulf. Rain chances will be gradually increasing ahead of the cold front that will cross the region Friday.
The mid level trough axis will exit our FA to the east around 00Z so only SChc PoPs will be possible through 06Z over SE OK. A secondary surge of cold, dry air is expected through the day Sat, as another polar trough digs into the upper Great Lakes region and strong northwest flow continues on the backside of the longwave trough.
In the upper levels there is a trough in the Central U. and a ridge in the Eastern U. As this system moves eastward a cold front will move through on Friday afternoon.
N winds assocd with the cold front will be near I-20 by 15Z and with an isallobaric high of 7-9mb/3hr gusty winds are expected, 20-35 mph sustained (BLDU across the PB). Winds will be stronger across the Lower Trans Pecos/Marfa Plateau/Alpine with a tighter MSLP gradient and we will issue a wind advisory there too from 12Z- 18Z. Models insist there is a secondary shrtwv trof within mid level flow that will generate light precip from SE NM into PB between 12Z-18Z this morning. Even though sunshine is expected by mid PM we will side toward the cooler MOS. NW flow persist into Wed-Fri, but warmer.
Strong cold front affects NE OK sites ~15-16Z, SE OK/far NW AR around midday, and KFSM by 20 or 21Z. The timing of the cold front and associated wintry precipitation remains largely unchanged. Forecast soundings suggest that the precipitation will begin as all rain, with freezing drizzle possible initially given the dry air aloft. Precipitation should quickly transition to a mix of sleet/freezing drizzle, and eventually to snow, as the entire profile becomes saturated and cools below freezing. We think the onset of freezing precipitation should begin by late morning through early afternoon across northeast Oklahoma, mid afternoon across northwest Arkansas, and late afternoon for areas in western Arkansas through far southeast Oklahoma. It just takes a little freezing drizzle to create slippery driving conditions, and flash freezing is definitely a concern given the shallow cold air mass.
1128 PM CST Wed Jan 10 2018 IFR/LIFR conditions expected overnight into Thursday ahead of a cold front that will bring showers and isolated thunderstorms across the region on Thursday afternoon. /issued 1000 PM CST Wed Jan 10 2018/ Areas of very light rain and/or patchy drizzle continue to affect our southern and eastern zones this evening as warmer S/SW flow aloft continues to feed into the region and increasing the depth of moist layer below 5Kft, which is where the steep temperature inversion is location per the 00Z SHV sounding.
Main concerns going forward with today's forecast include the following: 1) Pre-frontal rainfall that may quickly freeze as cold air surges in behind the cold front this morning. This could lead to a flash freeze-type scenario, especially on area roadways and exposed surfaces such as bridges, overpasses, and sidewalks; 2) Light freezing drizzle and sleet resulting in a light glaze immediately behind the cold front; and 3) Deformation band snowfall across far northwest Missouri and northeast Kansas where totals could reach 5 inches in spots, especially across Atchison County, MO.
The very cold air of the last three weeks could allow for some roads and sidewalks to become slippery tonight even as air temperatures stay above freezing. The low clouds and fog may produce some air travel delays through early Thursday. Some sleet or freezing rain is possible for awhile before the change to snow, though think the precipitation will be largely rain or snow. Sub freezing temperatures may not reach the lakeshore until evening.
The main trough continues to shift eastward toward the plains states this evening, with Arizona in northwest flow on the back side of the system. Expect the highest elevations to pick up some additional light accumulations of 1-3" through around midnight, then look for activity to diminish. The taste of winter felt over the past 24 hours will be brief as a ridge of high pressure amplifies over the area and dominates weather for the next several days. A weak pressure gradient under the ridge will also promote light winds through the weekend. An exiting low pressure system will continue to bring isolated to scattered rain and snow showers over higher terrain tonight, greatest activity over far eastern zones. On Thursday and Friday, strengthening high pressure will lead to a warming and drying trend.
The cold frontal boundary swept through bringing intense north winds and gusts have averaged 35 to 45 mph, and a few locations have topped 50 mph including KHSI with a peak wind of 52 mph. Narrow frontogenetic snow bands associated with the progressing upper trough axis have been developing and working east across our region early this morning. The highest snow amounts we have heard of so far include amounts near 2 inches at the North Platte NWS office and around 4 inches at Thedford. In northwest flow aloft, energy associated with a Canadian trough will translate southeast through the Upper Midwest and Plains region, sending a reinforcing shot of cold air on Friday.
457 AM EST Thu Jan 11 2018 An upper-level composite analysis this morning reveals a deep anticyclone covering much of the western North Atlantic Ocean, with a deepening trough advancing eastward across the central United States. Locally, Key West Doppler Radar base reflectivity scans have been largely void of precipitation echoes over *most* of the service area, the exception being the lower Florida Keys between the Seven Mile Bridge and about Sugarloaf Key. The rain should end this morning over the lower Keys, with clearing and weather to follow. Temperatures will be mild, slightly above average, today through Friday, before the next cold front approaches.
This will in general mean a quick transition just before sunrise on Fri across western portions of the mid state from rain to freezing rain to light sleet/light snow and then all light snow, and this continuing eastward thru the mid morning thru early afternoon hours.
All is calm this morning under a weak weather pattern and ahead of a series of short wave troughs later today through Friday morning. The most impactful trough is expected during the overnight hours, from about midnight to 6 am, affecting all of SE Idaho in slightly different ways. First though, as the first trough passes through this afternoon and low snow levels are already in place; expect a period of snow showers before snow levels rise during the late afternoon/evening and precip transitions over to rain across the southern Snake River Plain.
155 AM MST Thu Jan 11 2018 Tonight, a cold front will start impacting our eastern counties by 18Z with entire CWA being impacted with rainfall by 00z. Along with the cold front, winds will pick up and shift with the passing fropa. Favored the GFS and the High Res ARW for winds.
Rain followed by small amounts of freezing rain, freezing drizzle, snow, and sleet are expected as temperatures fall well below freezing. While freezing rain or drizzle amounts are expected to range from a trace to just a few hundredths of an inch, a thin sheet of ice on roads will create impact.
The low levels will be within the dendritic zone so patchy light snow and flurries will remain possible, but the dry air should limit any potential.
The anticipated freezing drizzle has developed across portions of the area from Aberdeen to Miller. An area of low pressure and Arctic front will continue tracking across the region tonight through Thursday morning. Radar returns in central Nebraska will track northeast tonight with the upper level trough. A low pressure system clipping along in pattern on Friday may bring some light snow to the area (generally less than an inch is thought possible at this time).
Further southeast the rain will transition to a brief period of freezing rain then sleet to snow.
An arctic cold front situated over northern Nebraska will move rapidly southeastward and arrive tonight as an upper level storm system passes across western Kansas. Some light rain showers may develop this evening along an initial cold front. There could be a brief period of freezing rain before the changeover to snow. Snow amounts could reach as high as 1 to 2 inches in a few spots, and with the expected 50 mph winds behind the cold front, drifting and reduced visibilities at times can be expected. The main concern here is any freezing of the wet roads after the cold front passes, which would lead to slick spots and hazardous driving. Therefore, a winter weather advisory was expanded to include all of central and western Kansas for snow, blowing snow and freezing rain.
Short term guidance in good agreement on carrying strong cold front across southern WI during the morning and early afternoon. Freezing temperatures will lag behind by several hours as south central WI should drop below freezing by early afternoon and southeast WI by early evening. Road temperatures will lag surface temperatures by several hours, but should still fall below freezing in south central WI by mid to late aftn. This enhanced synoptic lift will coincide with low level temperatures falling below freezing and produce a more significant area of sleet and freezing rain.
Associated cold front currently through NW OK with impressive pressure rises noted across SW KS. The more progressive trend of the trough is maintained within the latest data, and while a secondary circulation center may develop near the Arklatex region, any enhance region of post frontal forcing is shown to be brief. As such, much of the precip type forecast falls in the rain to freezing rain to sleet transition with any snow potential remaining well into the cold air. Precip amounts also look to remain light given the brief shallow nature of the forcing and any frozen accumulation will be further limited by the timing of sub freezing sfc temps.
Increasing forcing from a prefrontal trough will result in scattered showers and MVFR ceilings developing near the terminals mid to late morning, with the arrival of an upper trough and associated cold front providing enough instability for isolated TSRA near CXO, IAH. /ISSUED 1009 PM CST Wed Jan 10 2018/ Warm front stalled near the coast just south of GLS. Some light fog north of the warm front around the GLS bay area but winds appear to be helping to maintain the stratus deck. Guidance split on where the warm front waffles to overnight. On a further note cold front racing south through KS with dryline/prefrontal trough in West TX slowly moving eastward. The prefrontal trough should swing eastward through the area Thursday afternoon with the cold front a 1-3 hours behind it.
1021 PM MST Wed Jan 10 2018 01z surface analysis showed cold front racing through NE, well south of the CWA. Current surface analysis shows cold front now exiting far southern and southeastern portions of the forecast area, with much colder air quickly pushing in behind it. Thursday will be cold and dry with highs ranging from the single digits over northwest SD to the 20s over the higher elevations of northeast WY and the Black Hills.
Arctic high pressure continues to build into the region. An upper trough will cross the mid Missouri Valley today. Behind the upper trough axis, skies will become mostly sunny all areas as the day progresses.
The 10 pm EST surface analysis showed a rather strong high pressure system centered off the New England coast, providing east winds across our forecast area. Upper air data showed a vigorous southern stream trough moving into west TX, and Q-G forcing in advance of this system will begin over western portions of our forecast area later this afternoon.
An upper level trough pushes into the Southeast U. An associated cold front sweeps across the region on Friday with showers and thunderstorms.
Timing is everything this morning as the upper trof lifts northeast over the area and strong cold advection to support the changeover to snow slides southeast. The next concern is with some freezing rain/drizzle and ice accum potential along and east of the KS turnpike corridor as the surface cold front and colder sub-freezing surface air looks to outrun the colder air aloft and cloud ice for a time.
The ones that were made included smoothing the qpf amounts in southern IL, where the blend created a dearth between the higher qpf to the south and east, and the upper Low influenced snowfall to the northwest. Another impact factor is wind/gusts, which will sharpen late Thursday night-early Friday, just after the initial burst of freezing/frozen pcpn.
1102 PM EST Wed Jan 10 2018 Temperatures have dropped off even more in some of the sheltered valleys with ridge/valley temperature differences currently near 20 degrees across portions of the coalfields. These locations should remain largely decoupled for the remainder of the night with high pressure centered to the east of the area dominating. Elsewhere overnight lows will be downright balmy with temperatures only falling to the lower 50s.
909 PM PST Wed Jan 10 2018 High pressure aloft will build over California through the weekend. This will bring a return to dry and warmer conditions. After a chilly night, temperatures will begin a nice rebound on Thursday with highs some 5-15F degrees warmer compared to highs today (greatest change will be inland). High pressure aloft will continue building over the area through the weekend. Scattered to broken clouds along and west of the mountains this afternoon will gradually clear through Thursday as high pressure builds in from the west. The highest amount was 8.
Approaching Canadian cold front definitely means business this afternoon. Continued breezy to windy, and a bit warmer as the air mass moderates. Little change gleaned from the 12Z medium range models/ensembles depicting a fairly strong northwest flow aloft this weekend as a stout upper level ridge translates east into the western CONUS.
236 AM MST Thu Jan 11 2018 Latest upper analysis shows a trough over central North America with the trough axis currently moving eastward and away from the forecast area. At the surface, cold high pressure is moving into the region from the northwest. The winds will diminish some this afternoon but cold temperatures will remain, with the afternoon highs ranging from the lower 20s over parts of northeastern Wyoming and the Black Hills, the the single digits above zero over northwestern South Dakota.
As a cold front approaches from the north, a stratus deck is expected to develop late tonight with MVFR to IFR conditions possible through early Thursday morning. Thursday afternoon as winds shift to the north and increase behind the cold front, conditions will improve to VFR, but winds will become strong with gusts to near 35 knots at times late in the day. Trailing cold front from this feature will move across Deep South Texas on Thursday afternoon. Behind the front, west to northwest winds will become elevated and moderately gusty, with drier and cooler air moving in.
317 AM CST Thu Jan 11 2018 For today arctic cold front will move quickly east through the area. However, there may be a brief period of freezing drizzle at the onset of this precipitation. The second area of 800 to 500 mb frontogenesis (associated with the mid level trough moving out of the Dakotas) will bring another round of accumulating snow to southeast Minnesota and along and north of Interstate 90. On Friday night, another arctic cold front will move quickly southeast through the area.
Drier weather will return to the region Thursday as high pressure builds back over the area. H5 ridging and heights in a 580-584dm range will quickly spread into the area by Thursday afternoon with corresponding anomalous warmth only lagging these higher heights to the effect that temperatures Thursday result in a near normal range.
High pressure will maintain very warm and dry conditions for inland areas through Monday.
An upper level ridge will continue to strengthen over the region today and Monday. At the surface a thermal trough will remain along the coast, then will push inland on Monday.