Aikyam-Lab/Synoptic-Bench huggingface dataset:
320 PM CST Wed Dec 23 2020 Areas of light snow showers and flurries will impact locations mainly along and west/northwest of the Flint Hills corridor through late afternoon, in response to cold advection and steepening low- level lapse rates associated with an anomalously deep upper trough across the region. Otherwise, another chilly day is expected Thursday, as the influence of the expansive Mid-America upper trough will still be felt across Kansas.
Strong high pressure aloft will settle over the Great Basin through the end of the week.
The latest water vapor images show the strong upper low over northwestern IA moving toward the northeast. Upstream, ridging is over the western CONUS with some warm-advection clouds spilling toward the CWA. Currently, the gusty northwest winds continue to slowly diminish, with the high wind warning no longer in effect. After the system exists this evening, a ridge will build toward the CWA with warm advection through Christmas Eve and into Christmas Day.
358 PM MST Wed Dec 23 2020 The latest water vapor images show the strong upper low over northwestern IA moving toward the northeast. Upstream, ridging is over the western CONUS with some warm-advection clouds spilling toward the CWA. Currently, the gusty northwest winds continue to slowly diminish, with the high wind warning no longer in effect. After the system exists this evening, a ridge will build toward the CWA with warm advection through Christmas Eve and into Christmas Day.
Otherwise, clear conditions carry into Christmas Eve, as a transient ridge slides across the Great Basin. Temperatures will begin to rebound from yesterday's cold front, though, anticipate highs to continue running several degrees below normal. Expect slightly warmer temperatures by Friday morning thanks to mild WAA and increasing cloud cover ahead of this system. Weak high pressure will remain overhead early Friday before being punted to the east as a broad Pacific trough inches closer to the western coast.
Embedded shra this aftn within prefrontal trough should remain limited as better low level moisture return is delayed until evening. However better forcing lies within intense/strong cold frontal circulation through wrn IL and expect a more concerted band of primarily rainfall later this evening as it organizes further with ewd extent. Headlines needed nw late Thu aftn based on predicated better band organization timed with maximizing low level thermal trough, better flow veering and with time enhancing mid level moisture plume wrapping sewd out of WI. Prefer slower non- ncep inferred timing here with nrn cyclone track through the lakes Sun night and diminished precipitation response along swd trailing cold front given initial lagging moisture return into this sys. Low level jet focus also continues to shift eastward through the Lower Great Lakes this morning.
/issued 225 PM CST Wed Dec 23 2020/ Temperatures have warmed into the low to mid 70s across the area thanks to breaks in the cloud cover and an elevated southerly wind in advance of a strong strong cold front. Rain chances will increase ahead of the cold front with a threat for severe weather - including tornadoes, damaging winds, and hail. The cold front should arrive by these times: Woodville by 8 pm Beaumont. High pressure will settle in for Christmas with cold morning lows in the near 30 north to the lower 30s south.
Showers have increased dramatically across middle Tennessee ahead of mid level trough as intense low pressure area over the western Great Lakes moves into southern Canada and the associated cold front is now moving into west Tennessee late this evening. Strong south to southeast winds from the pressure gradient from higher pressure over western North Carolina to the lower pressure west of the eastern mountains was producing wind gusts already above 60 mph and winds to around 35 to 40 mph have occurred in isolated spots in the valley. Have sped up timing of the higher pops slightly with update from southwest to northeast and bumped lows up a degree or two over southern and central valley. or will occur around sunrise when cold front moves through western sections of the forecast area.
1224 AM EST Thu Dec 24 2020 Strong low pressure will bring rain Thursday, transitioning to snow Thursday night and continuing into Friday. Therefore, haven't made many adjustments to PoP timing as it will take some time for the low levels to saturate. The deepening and pivoting trough will maintain the residence time of precipitation across the region, supporting rather robust snow fall rates overnight into the morning hours of Christmas. Expect scattered snow showers and cold weather to continue Friday as the upper low/trough track across the Upper Ohio Valley region. Generally dry weather is expected for the weekend as the upper low exits and ridging builds in. Rain/snow chances return early in the week as a trough crosses the region. Another ridge should return dry weather by midweek in the amplified flow.
A cold front crossing the Mississippi has instigated a squall line of mature thunderstorms. Satellite derived moisture products indicate increasing moisture is just upstream, hinted by the increase in moisture and the subtle erosion of the low level stable layers (see KKEY RAOB). Small Craft Advisory likely will be required Thursday night for all coastal waters of the Florida Keys as a cold front produces a sharp blast of northwest to north winds. From synopsis, a high pressure cell east of the Delmarva will retreat slowly into the western North Atlantic tonight through Thursday. A strong cold front will blast through the Florida Keys very early Christmas Day.
The arctic airmass behind the strong cold front yesterday has already started to build into the region with the arctic front currently over northern Missouri. Winds will continue to remain relatively high for as the tighter pressure gradient will remain in place until tomorrow night, when high pressure slides into eastern KS. Those winds combined with the cooler temperatures will lead to the lowest wind chills of the season. The pattern will shift quickly on Christmas afternoon as ridging and southerly flow return to the region.
259 AM CST Thu Dec 24 2020 Early morning satellite depicts a large upper trof extending across the entirety of the Central Plains into the Ohio valley, as the storm that brought windy conditions and some snow to much of the plains lifts to the northeast. Cloud cover on the western periphery of the trof will move periodically through the forecast area today. This, along with incoming cooler high pressure, results in highs only in the 30s today that will feel a little cooler until the winds subside later tonight.
349 AM EST Thu Dec 24 2020 Strong low pressure will bring rain today, with a transition to snow by this evening. Snow showers should continue Friday with an upper level low. This low should track N along the front, reaching SW PA by evening. Will convert the Winter Storm Watch to a warning with increased confidence in 5-8 inches of snow expected as boundary layer flow becomes more optimal for upslope for a brief period tonight for the higher terrain SE of PIT. The upper low is expected to move across the Upper Ohio Valley region Friday, with scattered to numerous snow showers, and cold temperature.
Temps have stayed a little warmer than previously forecasted. The bulk of our precipitation will be out of the area by the time freezing temperatures arrive, which is why those west of I-65 have been left out of any snow discussion. Models are hinting at a very brief diurnal warm up with some temps creeping above freezing in the early afternoon. Still thinking the convective snow showers will occur later in the day, but if it comes earlier or these brief warmer temperatures hang around longer we may need to start talking mixed precip.
1126 PM EST Wed Dec 23 2020 Strong low pressure will bring rain Thursday, transitioning to snow Thursday night and continuing into Friday. Therefore, haven't made many adjustments to PoP timing as it will take some time for the low levels to saturate. The deepening and pivoting trough will maintain the residence time of precipitation across the region, supporting rather robust snow fall rates overnight into the morning hours of Christmas. Expect scattered snow showers and cold weather to continue Friday as the upper low/trough track across the Upper Ohio Valley region. Generally dry weather is expected for the weekend as the upper low exits and ridging builds in. Rain/snow chances return early in the week as a trough crosses the region. Another ridge should return dry weather by midweek in the amplified flow.
With an upper level ridge building over the region, expect drier and warmer air to move into the region through Christmas Day.
826 PM MST Wed Dec 23 2020 With an upper level ridge building over the region, expect drier and warmer air to move into the region through Christmas Day.
Warmer temperatures and lighter winds arrive for northern Arizona on Thursday. A s/wv ridge brings some warming and less wind for Thursday, after a very cold morning. A weak low moves through Christmas Day, this low may have enough moisture for a few flurries or light sprinkles. A weak area of low pressure will move across Arizona on Christmas Day with increasing clouds and slight chances for showers.
The airmass overhead will not be quite as cold tonight, but temperatures will be colder than this morning as high pressure comes in from the west. Went with the lower end of guidance, resulting in lows in the teens in most places.
High pressure will build into the region and winds will drop Thursday afternoon and evening. A ridge of high pressure moves through the area Thursday night with westerly flow expected to try to develop on Friday.
Strong high pressure aloft will keep things quiet through Friday. Clear and cold through Friday morning (except for patchy night and morning valley fog) with strong high pressure at the surface under northwesterly flow aloft. Meanwhile, high pressure aloft along the coast will come inland tonight, and over our area Thursday, then east of us Friday. This upper ridge will bring warmer air to higher elevations while valleys stay relatively cold, resulting in an inversion.
1231 AM CST Thu Dec 24 2020 Rapidly deteriorating conditions taking place! Gusty winds and a few showers here and there across the area ahead of deep low pressure and a strong cold front plunging into southeast MN and northeast IA. As of 2 pm, deep low pressure (~985mb) was located over Wabasha MN with a strong cold front extending southward through northeast IA. The low will continue to push northeast into northern WI/Lake Superior this evening and into Ontario by Thursday morning. Heaviest deformation snow axis with this low will be across south central into northeast MN with the eastern periphery edging into our northwest area. Some lingering snowshowers/flurries expected Thursday in cold cyclonic flow as the low pulls northeast into Ontario. Christmas Eve looks dry and cold as a ridge of high pressure build in from the west.
1137 PM CST Wed Dec 23 2020 Areas of light snow showers and flurries will impact locations mainly along and west/northwest of the Flint Hills corridor through late afternoon, in response to cold advection and steepening low- level lapse rates associated with an anomalously deep upper trough across the region. Otherwise, another chilly day is expected Thursday, as the influence of the expansive Mid-America upper trough will still be felt across Kansas.
222 AM CST Thu Dec 24 2020 Currently have a deep upper trough extending from the Upper Mississippi Valley, down into Central TX. At the surface, low pressure has now lifted into the Northern Great Lakes region with high pressure moving into the southern High Plains. Strong northerly upper flow will be in place today across the Plains as the sharp upper trough moves off to the east. At the surface, a weak ridge will slide over the area. As the upper trough moves off into the eastern CONUS for Fri, a weak upper impulse is expected to move out of the Desert Southwest and into West TX. This will result in some lee troughing, setting up some great downslope conditions for Fri. This will cause a cold front to surge south Sun into Sun night.
1046 PM CST Wed Dec 23 2020 A cold front will continue to progress eastward across eastern MO and southwestern IL this afternoon into early evening. Gusty westerly winds with the CAA will continue through tonight but should become slightly lighter with weakening pressure gradient as the cold front continues eastward, away from the forecast area. Pfahler On Friday, the upper-level trough will begin to depart the Midwest as it slowly propagates eastward toward the Northeast. Large-scale subsidence via mid-level height rises behind the trough should provide clearing of most clouds through the day.
The next question will be the longevity of the highest winds. Have trended towards the cooler end of guidance for lows as radiational cooling should be more than efficient. Surface ridging spills into the area tomorrow in the wake of today's system and should lead to a much quieter weather day. Heights build aloft as a ridge begins to translate into the Plains during the day Friday. H85 temps look to warm from below freezing to near 8-10C by Friday evening as warm downslope flow begins.
Well, the cold front has arrived. Those winds may be gusty this evening, with the initial push of this cold front; however, surface winds will diminish after midnight. As is usual, for this time of year, cold fronts bring colder air, and this one is no exception.
547 AM CST Thu Dec 24 2020 Updated for 12Z aviation discussion 12Z TAF discussion: Showers continue to bring IFR/MVFR conditions to PIB/HBG this morning as the cold front moves east of the area. VFR conditions are returning to the remaining TAF sites, as high pressure ridging builds in across the area. The tail end of a boundary briefly passes Friday and may bring a few clouds at the high drifts east.
Cooler daytime temperatures will occur today under increasing cloudiness, but a return to above normal readings is expected Christmas Day and this weekend. Otherwise, warmer temperatures will return to southeast Arizona this weekend.
308 AM MST Thu Dec 24 2020 Upper ridging settled across the western U. Looking beyond and into the weekend, upper ridging will flatten while the next trough digs into the Pacific Northwest.
/issued 318 AM CST Thu Dec 24 2020/ An upper level trough extends from over the Upper Midwest to over Texas. The upper trough will move eastward today with temperatures across the area staying cool with highs mostly in the 50s.
Friday night, the deep eastern trough pivots away towards the western Atlantic, with significant 500 mb height recovery across the Ohio and Tennessee valleys.
Warmer temperatures and lighter winds arrive for northern Arizona by this afternoon.
522 AM CST Thu Dec 24 2020 Updated aviation section for 12z taf issuance In the wake of the strong cold front, temperatures have steadily dropped overnight. Highs will be around freezing. Since there probably will be another batch of low clouds and flurries over those areas, highs will be on the lower end of guidance. Forecast highs on Christmas will range from the lower 20s over sw Indiana to the upper 20s near the Mississippi River. The Ozark foothills will reach the lower to mid 30s due to lots of sunshine and some downsloping west winds.
419 AM EST Thu Dec 24 2020 A deep upper trough moving through the MS River Valley today into this evening will push a cold front across the forecast area today. 00 inches are possible at the highest elevations.
547 AM EST Thu Dec 24 2020 Strong low pressure will bring rain today, with a transition to snow by this evening. Snow showers should continue Friday with an upper level low. This low should track N along the front, reaching SW PA by evening. Will convert the Winter Storm Watch to a warning with increased confidence in 5-8 inches of snow expected as boundary layer flow becomes more optimal for upslope for a brief period tonight for the higher terrain SE of PIT. The upper low is expected to move across the Upper Ohio Valley region Friday, with scattered to numerous snow showers, and cold temperature.
Meanwhile, local radars are detecting a few patches of light showers, one near the Lower Keys and southeastward into the Straits, and the latter along the Upper Keys and adjacent waters. A deep full latitudinal trough extending from Central Canada equatorward to the south central Gulf of Mexico today will lift northward through Friday, with the majority of the large scale lift remaining well north of our region. Meanwhile, a spell of weak upglide will prompt low chance pops this morning, until a swath of high moisture associated with low level confluence preceding and accompanying a cold front which will blast through our entire region by very early Christmas day.
334 AM MST Thu Dec 24 2020 We will be in for a quiet stretch of weather the next few days as a transitory ridge works out of the West and across the spine of the Rockies. The 24/00Z hand analysis chart as closed low sitting off the California coastline. The arrival of the ridge and warmer air aloft will lead to prime inversion conditions to end out the week. especially in the high country.
645 AM EST Thu Dec 24 2020 A deep upper trough moving through the MS River Valley today into this evening will push a cold front across the forecast area today. 00 inches are possible at the highest elevations.
(Today and tonight) Calmer conditions are expected throughout the day today as the upper level trough and associated surface cold front continues to exit the region into the southeastern US.
An upper level ridge will continue to slide eastward over the rockies through tonight with northwesterly flow over the Central High Plains. Lows tonight are progged to dip into the low to mid 20s. Dry conditions continue Christmas Day through the weekend as the aforementioned ridge of high pressure slides through the area.
425 AM MST Thu Dec 24 2020 Updated Aviation Discussion An upper level high pressure ridge moving into the region will maintain dry and relatively mild conditions through Christmas Day.
306 AM MST Thu Dec 24 2020 An upper level high pressure ridge moving into the region will maintain dry and relatively mild conditions through Christmas Day.
Mostly clear to partly cloudy skies on Friday under the upper ridge and with the decent mixing could see highs climb into the 30s and 40s.
418 AM MST Thu Dec 24 2020 Strong high pressure aloft will settle over the Great Basin through the end of the week.
Early morning satellite depicts a large upper trof extending across the entirety of the Central Plains into the Ohio valley, as the storm that brought windy conditions and some snow to much of the plains lifts to the northeast. Cloud cover on the western periphery of the trof will move periodically through the forecast area today. This, along with incoming cooler high pressure, results in highs only in the 30s today that will feel a little cooler until the winds subside later tonight.
So maybe we will have a white Christmas after all! But first, high pressure reigns supreme today and continues through much of Christmas Day.
454 AM CST Thu Dec 24 2020 (Today and tonight) Cooler conditions will be in place across West Central Texas following a recent cold frontal passage.
This trend will continue as we head into the overnight period, so be sure to bundle up if heading outside! Upper level ridge will move overhead the region Christmas Day, allowing afternoon highs to rebound into the upper 20s to 30s, with the warmest temperatures forecast to occur west of the James River.
A high pressure overhead will provide quiet weather conditions with moderating temperatures for Christmas day. This will allow a surge of warmer 850mb temperatures to move through. Skies should remain mostly sunny thanks to the subsidence of the high pressure.
419 AM MST Thu Dec 24 2020 Western NOAM ridge will shift east and allow for mild and dry conditions through the end of the week. Much warmer conds can be expected today in the western 2/3 with even warmer temps Friday as the ridge shifts east.
537 AM CST Thu Dec 24 2020 (Today and tonight) Calmer conditions are expected throughout the day today as the upper level trough and associated surface cold front continues to exit the region into the southeastern US.
351 AM CST Thu Dec 24 2020 Latest water vapor imagery is showing longwave trough extending from the Upper Midwest into the southern Plains. Winds are slowly decreasing early this morning as this low moves northeast further relaxing the pressure gradient over the area. There was also a secondary cold front extending from southern Iowa northwestward into the northern Plains. So with some sun, highs will range from the lower 30s over central Missouri to the mid 20s over south central Illinois. Britt EPS and GEFS mean continue to show the upper flow becoming more zonal over the weekend as the longwave lifts out of the area and the longwave ridge over the western CONUS flattens out as it moves east into the Midwest.
/issued 331 AM CST Thu Dec 24 2020/ It is chilly and dry early this morning with 08Z temperatures ranging from the lower and middle teens across southwest Texas Panhandle and western South Plains to the lower and middle 20s off the Caprock. This very dry airmass will linger over the region today as the upper trough that opened the door for this colder air to spill into the region yesterday shifts eastward and evolves into a large closed low over the Ohio River Valley tonight. Dry downslope flow and full insolation will allow temperatures to rebound to near average, in the lower to middle 50s, this afternoon.
317 AM CST Thu Dec 24 2020 Cold front barreling through the area, near a Slidell to New Orleans to Houma line at 3 AM CST. Seeing about a 15 degree drop in temperatures behind the front, with mid-upper 60s ahead of the front, and already into the lower 50s in northwest sections of the area.
An upper level ridge begins to move into the area on Christmas with high temperatures reaching the 40s and 50s.
331 AM CST Thu Dec 24 2020 It is chilly and dry early this morning with 08Z temperatures ranging from the lower and middle teens across southwest Texas Panhandle and western South Plains to the lower and middle 20s off the Caprock. This very dry airmass will linger over the region today as the upper trough that opened the door for this colder air to spill into the region yesterday shifts eastward and evolves into a large closed low over the Ohio River Valley tonight. Dry downslope flow and full insolation will allow temperatures to rebound to near average, in the lower to middle 50s, this afternoon.
207 AM MST Thu Dec 24 2020 Western NOAM ridge will shift east and allow for mild and dry conditions through the end of the week. Much warmer conds can be expected today in the western 2/3 with even warmer temps Friday as the ridge shifts east.
After a frigid start this morning with some of the coldest temperatures so far this winter season, an upper level ridge will shift east toward New Mexico, brining sunny skies, warmer temperatures and much less wind than yesterday. The upper level low will likely amount to nothing more than increased cloud cover as it fills and opens up by the time it reaches the AZ/NM border late day.
302 AM CST Thu Dec 24 2020 In the wake of the strong cold front, temperatures have steadily dropped overnight. Highs will be around freezing. Since there probably will be another batch of low clouds and flurries over those areas, highs will be on the lower end of guidance. Forecast highs on Christmas will range from the lower 20s over sw Indiana to the upper 20s near the Mississippi River. The Ozark foothills will reach the lower to mid 30s due to lots of sunshine and some downsloping west winds.
/issued 305 AM CST Thu Dec 24 2020/ A potent cold front has pushed through the Mid-South this morning. Expect highs to range from the lower 30s to lower 40s. Can't rule out some scattered flurries occurring this afternoon as an upper trof moves through the region. Arctic high pressure will settle over the Mid-South for Christmas day. Highs will struggle to get above freezing across much of West Tennessee.