Aikyam-Lab/Synoptic-Bench huggingface dataset:
1245 AM EST Tue Dec 26 2017 Strong ridge continues to build in from the north and as the center shifts northeast of the CWA, we will see the fetch mainly out of the east by morning. Fairly dense cirrus deck skirting across from the west which may limit min temps to a few degrees warmer than if we were under clear skies, though still expecting temps reaching upper 20s to low 30s for most locations. Should see no impacts as long as temps stay in the mid to upper 30s as forecast but with very dry low levels at onset could be some quick cooling to near freezing.
An area of low pressure and trough axis across Ontario is helping push some of this arctic air into Michigan. However that will not lead to any warm up, as high temperatures will still struggle to reach the lower teens.
There will be a few hours (03z-08z) where mid level moisture increases in conjunction with the moisture at the lower levels providing a seeder feeder scenario and producing categorical pops for snow and lower visibilities generally along and north of the interstate. With 850mb temperatures in the zone for favorable snow growth I added a chance of flurries and freezing fog.
Northwest flow aloft Tuesday with a weak ridge over the area.
At the surface, an Arctic high pressure ridge will remain in place over North-Central MT, while a front remains draped over Southwest MT and moves little through the period.
The weak trough will move along the Texas Coast today aiding in the isentropic lift/overrunning pattern that is in place. A weak cold front will also push south through the area between noon and 6pm tonight further enhancing the chance for showers. The front today will help reinforce the cooler air in place so lows tonight will dip into the mid to upper 30s, with highs only warming a few degrees for Wednesday, topping out in the upper 30s to mid 40s.
Some of the coldest air of the season will affect central Indiana this week as broad cyclonic flow and Arctic high pressure dominate the pattern. But again, accumulations will be minimal with these disturbances as well, maybe 1 to 2 inches on the high end. This is a high confidence forecast with a broad area of low pressure centered over Ontario and Arctic high pressure settling into the central U. Dry conditions will prevail throughout the period as Arctic high pressure strengthens over the area.
Light snow accumulations of up to 2 inches are expected in the higher elevations of Baker County, and in the West Central and Boise Mountains of southwest Idaho. Moisture spilling up and over the ridge anchored offshore will create chances of precipitation for our northern mountains for the start of the period.
Today through Wednesday: Front will dissipate over the area as high pressure builds over the eastern US and a ridge nosing into Florida from the northeast will allow a northeasterly flow today through mid week.
The dry air in the advancing ridge will keep our northern counties mainly dry, but enough forcing in our southern counties will be present to help produce precip reaching the ground. The high resolution models have varying amounts of forcing for precipitation, with a couple models barely producing any QPF in our forecast area. Regarding the temperatures, winds will be diminishing over the northern CWA overnight, as an axis of high pressure builds southeast into the area. Likely to see some sub-zero readings in the colder spots, but the lower winds should help keep wind chills above advisory levels (though still below zero as far south as I-70).
One unfortunate trend if you want widespread moisture is that deterministic and various ensemble model suites all show a persistent upper level long wave ridge over the west coast which will continue to steer any significant Pacific moisture into the Pac NW and over the northern Rockies.
Expansive Arctic high pressure ridge covers the CONUS east of the Continental Divide.
A few enhanced clouds remained over the high terrain along the northern divide and Wyoming border. RADAR and ASOS obs showed that snow has ended for all but the highest mountain peaks and passes. Northwest flow aloft will continue through the period with a large scale cyclonic trough over the northeastern CONUS.
250 AM MST Tue Dec 26 2017 Current surface analysis shows arctic front well south and west of the forecast area, with high pressure centered over far eastern MT. Upper level analysis continues to show low over western Ontario, with broad trough covering much of Canada and the US.
As a result expect a fairly isothermal day on Tuesday, with the where the high and low temperature may only be within 10 degrees of each other. And given that the high for the central and northeast Panhandles is forecast to be in the mid 20 up to about freezing, it will feel pretty cold out there all day Tuesday. At best this looks like freezing drizzle, not freezing rain. The majority of the forecast will still have the Panhandles under northwest flow, as a very large upper level trough engulfs the northern, central, and eastern CONUS.
Moisture actually increases in the lower levels which could actually support more flurries. This is generally in the middle of the model envelop of deterministic solns and slightly warmer than the rapid refresh models.
1253 AM EST Tue Dec 26 2017 High pressure will prevail through Tuesday. Weak low pressure may develop offshore mid week as strong high pressure builds from the north.
1023 PM MST Mon Dec 25 2017 A broad upper trough remain across much of the CONUS today with cold northwest flow across the northern Plains. Arctic high pressure sits across eastern MT through the Dakotas, with the frontal boundary just west and south of the CWA.
With just a weak front over SW MT and high pressure moving over the plains, winds will remain light at all locations. At the surface, an Arctic high pressure ridge will remain in place over North-Central MT, while a front remains draped over Southwest MT and moves little through the period.
The high and mid clouds are also in advance of a upper level disturbance. A cold period is indicated with a trough in the upper atmosphere anchored across Eastern North America.
High pressure strengthens midweek with a modest warming trend although nights will remain seasonably cool. Unfortunately upper level ridging remains off the coast keeping storms north of the area. The upper ridge will build up a little more later in the week bringing a few degrees of warming.
Today will actually be one of the warmer days with lows starting out in the 20s and highs reaching the upper 30s to lower 40s. A dry cold front will move across the area tonight, bringing much colder temperatures for tomorrow with lows in the upper teens and lower 20s Wednesday morning and highs only rising into the upper 20s to mid 30s.
Otherwise wind will generally be light and variable overnight then shifting to the NE as a cold front moves down into the area during the afternoon. A long-wave upper trough that has settled over much of the CONUS was responsible for very cold air across the eastern half of the U. Confidence is increasing that warm, moist air will override the cooler airmass just above the surface beginning Tuesday evening across the eastern Permian Basin. Temperatures will fall to or just below freezing over much of the Permian Basin by early Wednesday morning creating an opportunity for freezing drizzle for a few hours. Not expecting much to accumulate, but it doesn't take much of anything frozen to create problems on roads and bridges.
A secondary cold front will cause winds to shift from southeast to east to northeast during the forecast period. With clouds in place all day on Tuesday, expect a warmer start in the morning with lows in the 40s and highs in the 50s and 60s much areas.
Some cloud cover may persist through tonight and with 5 to 10 mph east winds, temperatures shouldn't fall below the lower single digits. A series of upper level troughs progressing southeastward out of Canada will bring renewed batches of arctic air through this weekend.
High pressure ridge axis remains in place from western Canada into the lower Missouri Valley at 20Z with H850 frontal zone from western Nebraska toward the Kansas southeast Nebraska border.
Temperatures struggled to warm out of the lower 30s as winds were light and variable. Canadian high pressure was directly over the area however, a speed max approaching from the west within the upper westerlies was forcing some echoes over Kansas and Oklahoma this afternoon.
1129 PM CST Mon Dec 25 2017 This Evening-Tue Night: This afternoon a STRONG upper-deck cyclone covered most of Ontario that is producing a few jet maxima that are, meteorologically speaking, breaking the sound barrier. The strongest upper-deck jet that is screaming ~140kts around the base of the cyclone stretched in a NW-SE manner across the Lower Great Lakes while a second max ~130kts stretched from Southeast MO to the Western Ohio Valley. The light snow may spread into Central KS late tonight & Tue morning as the lower decks slowly moisten.
Along and west of this front, snow has stopped and temperatures have climbed into the low to mid 30s.
Very persistent top-down saturation will have to occur over several hours for snow to be able to reach the surface without sublimating, but most hi- res models are indicating that by around 12z, the lower level atmosphere may finally saturate and allow for a few hours of very light snow.
A cold front will move through the are late Tuesday morning into Tuesday afternoon, resulting in north winds of 6 to 12 knots. in response to lee side troughing across western Kansas and the Panhandle. During the day on Tuesday yet another cold front will move across the area resulting in temperatures in the lower to mid 40s in the Big Country with 50s across the southern half of the area. Another shallow arctic airmass will be over West Central Texas by Tuesday evening, with the cold front south of the area. Temperatures will probably be below freezing across the Big Country and northwest Concho Valley for possible patchy freezing drizzle Tuesday night. The main impacts will be slick bridges and overpasses. Otherwise, temperatures should remain above freezing for just light rain across the remainder of the area.
Cold day continues with high pressure across the region. Tuesday night through Wednesday night, dry and very cold, as strong high pressure, 1040+mb moves southeast from the Upper Midwest to the Great Lakes and Ohio Valley regions. Ridging will be seen all the way to the southern Plains and TX as well. The semi-permanent western Hudson Bay low and eastern Canadian low persisting this week an into the New Year, a very broad low amplitude trough will continue to usher in cold air east of the Rockies and through the WFO PAH forecast area. However, the combination of the low amplitude cyclonic upper flow, the persistent northwesterly flow near the surface, and the absence of deeper layer moisture and enhanced cyclogenesis in the flow almost guarantee minimal to non-existent chances for any significant snowfall development.
345 AM CST Tue Dec 26 2017 Wind chill headlines remain in place as center of 1045mb high pressure remains across eastern Montana with a ridge axis extending southeast into South Dakota/Nebraska. With this high overhead, and no high clouds evident, anticipate temperatures will again rocket down into the teens and 20s below zero tonight - though the low temperature forecast is again tempered by the lack of a complete snow cover. As the high begins to move off, we see a buckling of the cold air back to the east in return flow.
I went a tad cooler for highs Tuesday with fresh snow on snow and plenty of sky cover for most of the day, expecting highs near 10 for most of the area. Longest sub-freezing stretch in the Tri Cities in nearly 4 years?.
900 PM PST Mon Dec 25 2017 A ridge of high pressure along the West Coast will dominate our weather through the end of the year.
Cooler, but near normal temperatures in the 40s north to 50s central and south can be expected early this morning before warming into the 70s this afternoon. High pressure situated over the SE US will maintain the northeast-east wind across the area with limited layered moisture expected in the vertical which will support abundant sunshine today. Moisture advection develops on Wednesday ahead of a developing trough/frontal boundary over the northern Gulf of Mexico.
Winds continue out of the E, but back to NE during late Tuesday as a back door cold front arrives. Low clouds to maintain slightly warmer low temperatures in the mid 30s while the remainder of the ArkLaTex falls below freezing.
The exception will be as the high departs Wednesday morning allowing southerly return flow to increase.
02 UTC surface analysis shows an area of high pressure across the Cumberland Plateau of Middle Tennessee. From watching the trends since sunset, it seems as though it's more likely that areas from Southwest Georgia into Southeast Alabama and into the Florida Panhandle will have the best chance of reaching the freezing mark, with some areas in Southeast Alabama likely to drop into the upper 20s. Areas further east in the Florida Big Bend and South Central Georgia are less likely to reach freezing.
A broad upper trough and jet stream will persist over TN this morning, and will continue to keep broken to overcast midlevel cloud cover during that time. In the afternoon, the moisture should retreat as the jet lifts northward, and with scattered clouds and near neutral advection in a light low level flow, highs will be a warmer than yesterday, in the uppper 30s to mid 40s.
348 AM CST Tue Dec 26 2017 As of 09Z Tuesday morning, the stubborn ridge/trough mid-level pattern continues across the CONUS. At the surface a stout anticyclone continues to intrude on the central Plains with reinforcing CAA.
An east to west oriented stationary boundary now over the central gulf will gradually advance north as a warm front and stall once again over the northern gulf. Rains to continue into the overnight hours Wednesday ahead of a cold front that will push down from the north.
and occasional mostly cloudy for the coastal areas as low level convergence increases as a weak inverted trough develops offshore. Models are in disagreement in the development of a few showers with the trough offshore.
The lowest ceilings look to be in the southwest toward KSPS, KLAW and to some extent KHBR and KCSM. There is also a better signal of some drizzle by the NAM and the high-resolution models at KSPS and likely KLAW. Right now, it appears that the drizzle will most likely develop after temperatures warm to above freezing in the morning, but there is some potential for freezing drizzle to develop earlier before temperatures warm, although not enough probability to introduce FZDZ in the TAFs at KSPS or KLAW, but will watch trends. Cold front currently just near a KRSL-KGCK-KEHA-KCAO line will move southeast into and through the area this evening and overnight. The lowest ceilings are expected to be in the southwest, especially at KSPS with some potential of IFR ceilings Tuesday morning.
Soundings indicate good saturation in the lower levels overnight and cold enough for snow. This could take readings in those areas well above freezing by late in the day, while readings elsewhere remain below to well below freezing.
358 AM CST Tue Dec 26 2017 Broad upper level trough was located over central Canada and the Northern Plains. Water vapor loop indicated an upper level trough over southern SASK will move southeast over the area today. Ridge will move over the forecast area tonight. Upper level trough over the Yukon will rotate into southwest Canada by 12Z Wed. Downstream ridge will approach the area Wed morning.
Cold conditions will continue through the forecast period as broad cyclonic flow remains in place over much of the country and Arctic high pressure settles into the region. There will be a few chances for light snow late in the week and into the weekend as more substantial disturbances reinforce the larger scale troughing over the region.
High pressure at the surface will keep our weather cool and generally quiet through tonight. There is a fair amount of dry air in the low levels, but opted to include some isolated snow showers or flurries late today into tonight. High pressure just off to our southwest will keep us dry through the period. As the high pressure spreads eastward and the trough moves off to the northeast, temperatures will increase somewhat towards the end of the work week.
For tomorrow, cold high pressure will prevail over the Great Plains. Therefore, the highs we have might be a bit warm, particularly across the eastern zones.
100 AM PST Tue Dec 26 2017 A persistent ridge of high pressure along the west coast will provide a quiet and dry end to the year. Winds may become breezy along the Sierra ridgetops as 700mb winds brush the northern Sierra.
243 AM EST Tue Dec 26 2017 A trough of low pressure will drop south through the region today and tonight.
Winds will remain gusty over the higher passes so there will continue to be areas of blowing snow thru the day. Winds will remain gusty over the higher terrain with some blowing snow over the higher passes.
There will not be much relief today as temperatures are only expected to climb into the lower teens as wind chill values stay near or below zero.
1216 AM EST Tue Dec 26 2017 Low pressure moving through the Canadian Maritimes will continue to deepen as high pressure builds from the west. The high will dominate from mid to late week. Snow showers have ended across the area, and other than increasing cloud cover the main story will be the beginning of a cold stretch as arctic high pressure builds across the area. Dry but cold weather will prevail with high pressure building from the west. The 12z EC is a bit more amplified with the upper trough leading to intensifying low pres tracking just S and E of the 40N 70W benchmark Sat eve which is slightly earlier and farther S as compared to its 25/00Z run. High pressure builds south of the area today.
Winds will be westerly with sustained speeds in the low-mid teens and gusts in the upper teens to low 20KT range. Temps will only get into the teens for maxes in the NW Tuesday, and near freezing in the far SE.
A cold front will be pushing through Tuesday night so expect winds to increase from the NNE as this happens. Surface analysis has cold front stalled well into the central Gulf of Mexico this evening. High pressure stretches from the central Plains to the Mid-South.
A cooler/drier airmass has settled over the region and will continue through the night. In fact, a large area of high pressure will continue to our north for the next several days, likely resulting in moderate easterly surges each night.
Cold front which passed through the state early today has kept temperatures from climbing much during the day. Readings will fall into the evening as cooler commences with winds remaining modest into tonight. Also have extended the advisory another row of counties farther south with apparent temperatures around -20 along the highway 30 corridor by daybreak. Given the a good portions of the low level thermal profile will be in the dendritic layer overnight, anticipate at least some flurries or light snow across the southwest starting later this evening into the overnight. The clouds will also keep readings a bit warmer overnight as well despite the fresh snow cover. Generally sunny skies on Tuesday with only minor rebound of temperatures as thermal trof remains near the northeast corner of the state with neutral temperature advection.
While southern Missouri will once again climb a bit above freezing.
A ridge of high pressure will remain stationed along the west coast of the United States into the coming weekend.
With the jetstream just to the north and a broad upper trough over the region, high and midlevel clouds will be predominantly broken through the period. At the surface, high pressure to the northwest will provide a light northeast wind that should not exceed 10 kts.
Temperatures will remain cold over the next few days with highs struggling to reach the freezing mark again today. Lows tonight will feature a rather sharp gradient as a cold front drops in with the second wave passing by tonight.
/issued 423 PM EST Mon Dec 25 2017/ Synopsis and near term (through this evening): A weakening surface cold front continues to move farther south into South Florida late this afternoon. A ridge of high pressure builds into the southeast states and winds behind the boundary veer to a more northeasterly direction with time.
Clouds have kept temperatures in the lower to mid 30s thus far, but some clearing is expected by sunrise. /issued 338 PM CST Mon Dec 25 2017/ Cold temperatures and uncertainty with regard to a couple of potential rounds of Wintry weather are the highlights of this forecast update. Current temperatures are in the low to middle 30s across the Midsouth. A very broad trough is currently in place across the entire United States, centered over the Mississippi River. A reinforcing Arctic cold front will move across the Midsouth tomorrow ushering in a bitterly cold Arctic Airmass.
Away from the big lake, skies expected to be mainly clear early this evening as ridge of high pressure continues to nose in and across southern half of area. Lake aggregate thermal troughing will hold firm this period resulting in continued IFR/MVFR threshold flight rule invof KSBN. Somewhat better odds of more sustained IFR conditions similar to this past evening late this aftn in response to swd sag of mid level trough axis across the lakes and abt 20 degrees of veering in low level flow trajectories.
High pressure at the surface will keep our weather cool and generally quiet through tonight. There is a fair amount of dry air in the low levels, but opted to include some isolated snow showers or flurries late today into tonight. Strong Canadian high pressure dominates the short term, anchoring cold air in place and continuing the period of below freezing weather across the entire CWA.
A high-pressure ridge is forecast to persist along the US west coast through this week by deterministic and global ensemble model suites. This ridge will be associated with heights exceeding the 90th climatological percentile across the southwest U.
Cold air and upper troughing remain over the area this forecast period with lake effect snow continuing as well. In the extended, GFS and ECMWF show a broad 500 mb trough with cold air over the central U. The arrival of the arctic air mass will also result in periods of heavy freezing spray late tonight into mid week. Heavy Freezing Spray Warning until 7 AM EST Wednesday for LSZ249>251-266-267. Heavy Freezing Spray Warning until 7 PM EST /6 PM CST/ this evening for LSZ241>245-248-263>265. Heavy Freezing Spray Warning until 7 AM EST /6 AM CST/ this morning for LSZ162-240-246-247.
Next cold front turns winds northeasterly and increase during day Tuesday. High pressure building south will shift any precip potential south Tuesday night and Wednesday with colder air.
West to northwesterly flow will continue at 500mb through the period with a large trough fully entrenched across much of the central and eastern U. 00Z Wednesday will start with high pressure at the sfc, which will slowly exit to MN/IA by daybreak Wednesday.
A longer wave length upper level trough will remain nearly stationary and amplify across the Hudson Bay region of Canada, extending southward across the east central US.
But 700mb temperatures forecast to warm about 4C over yesterday, so would expect slightly warmer temperatures over yesterday. Start to see the effects of a low pressure system moving into Colorado Thursday as guidance begins to paints some light QPF over our western mountains.
In fact, readings were around freezing in portions of Boone and Newton Counties, with some freezing rain reported. Given that ice amounts will be spotty/light, opted to issue a Special Weather Statement to address the possibility of slick spots on bridges/overpasses. Precipitation will be along/north of a cold front that will stall in far southeast Arkansas or northern Louisiana.