Aikyam-Lab/Synoptic-Bench huggingface dataset:
After a chilling morning early Wednesday, southwest flow aloft develops with surface winds swinging south behind strong high pressure moving through the Plains. Wednesday will be a dry day with more sunshine, resulting in a slightly warmer feel than the previous few days.
An upper trough. An upper ridge in the Atlantic. High pressure south of the Canadian Maritimes drops southward to near Latitude 35 North/ longitude 60 West by late Wed while broadly ridging west. The ridging aloft and surface will be in command of the forecasts with warm.
224 AM EST Tue Feb 20 2018 Water vapor imagery and RAP analysis show a deep trof over the western CONUS (500mb height anomalies of 300m) and strong ridging over the eastern CONUS (500mb anomalies of 300m over the ne). probably closer to the lower end of that range. Upper air pattern consists of a 500 mb trough in the western U. and a strong 500 mb ridge over the sern U. The trough in the western U. In the extended, GFS and ECMWF show a 500 mb trough over the western U. 12z Fri extending up into the Canadian Prairies and a 500 mb ridge across the sern U. The trough ejects into the southern Rockies 12z Sat and into the Great Lakes Sat night. More troughing moves into the area 12z Mon into Mon night.
The proximity of a cold front which is currently stalled across Southeastern Kansas to Northeastern Missouri is expected to help provide a focus for lift and force thunderstorms today. Cold air will filter into the area behind the front which will allow for the potential for rain to change over to freezing rain along and behind the front. The short range models continue to show differences in rain amounts behind the front but the expectation is for a change over to freezing rain from northwest to southeast as the front moves through and cold air moves in behind the front.
1129 PM CST Mon Feb 19 2018 For the 06Z TAFs, based on some latest model guidance, have decided to speed up the cold frontal passage for all terminal sites for this fcst cycle. /Issued 550 PM CST Mon Feb 19 2018/ For the 00Z TAFs, a low confidence forecast with respect to cold frontal timing. This particular cold front has already moved thru much of the area nearly one day sooner than expected. Most computer models suggest the cold front may temporarily move back north into Kansas later tonight, then surge south again on Tuesday. Due to low confidence in cold frontal timing, amendments may become necessary later tonight.
1136 PM CST Mon Feb 19 2018 WV imagery was showing a longwave trof extending from central Canada to the southern CA coastline along with a subtropical moisture feed streaming northeastward from the southern Plains to New England. At the surface, low pressure was centered over southeast IA with a strong colds front extending into northern then to central OK. With the onset of precip, soundings show the dominate precip type will be light freezing rain over the central/southern CWA, with a mix of light freezing drizzle/sleet to the north before making a change over to all snow shortly after midnight.
This is producing a large band of freezing rain with embedded thunderstorms which themselves are producing some prolific sleet showers for brief periods. However, additional freezing rain will be expected in the southeast coincident with another wave moving northeast on the frontside of synoptic scale trof. Additional icing potential will now be greatest south of a line from Waterloo through Newton to Lamoni this morning with the exception of the far southeast corner of the forecast area which has temperatures currently near or slightly above freezing. Temperatures should plummet to below zero in the far northwest nearest the thermal trof with single digits above zero and teens farther southeast.
While the convergence in the mid levels exits pretty early this morning, the low levels remain fairly dendritic so may see some flurries through early afternoon. Cold high pressure settles into the area overnight so expecting some pretty cold lows on Wednesday morning. Wednesday will be a recovery day from the cold high pressure shifting southeast, but not expecting a whole lot of warming.
1225 AM EST Tue Feb 20 2018 A warm front moving northward in the forecast area tonight will lift north of the area Tuesday. High pressure will be off the coast coast this week and bring warm and moist air into the forecast area. However, the chance for showers remains low through the rest of the week because of strong upper ridging over the Southeast. Based on the NAM LI pattern a lingering warm front will be in the forecast area tonight. It will be drier aloft associated with upper ridging. Upper-level ridging into the Southeast will inhibit convective development. Mild temperatures will continue with lows in the low 60s. Models continue to show good agreement with the persistent upper level ridge over the region.
Then, high pressure will lead to warming temperatures and lighter winds from Friday into next work week. Beginning Friday, strong high pressure will build across the western United States causing a return of above normal temperatures by the weekend.
535 PM CST Thu Dec 7 2017 This afternoon, the upper air pattern reflects a longwave RIDGE over coastal western North America and a TROF over much of the middle and eastern portions of North America, with the TROF axis extending from the western Great Lakes southwestward to southern New Mexico. The TROF axis aloft will work its way thru our region tonight but uneventfully, with clear skies expected to persist. Combined with the presence of a weak RIDGE at the surface, should allow temps to plunge into the teens by early Friday morning, with some single digits possible in sheltered valley areas. Thanks to SW surface winds in the wake of the RIDGE axis, temps will recover closer to averages for early December, but still about 5 degrees below--or in the upper 30s and lower 40s.
However, the lower atmosphere is quite dry and most of the precipitation on radar is likely not reaching the ground. Some light echoes noted on KSHV radar likely not reaching the ground in most locations, as the dry air continues to deepen ahead of the approaching upper trof. Despite freezing temperatures expected tonight, any precip that is able to fall will be too light to accumulate. Freeze warning remains in effect for tonight, as we haven't seen widespread freezing temperatures across the. Upper trof will continue ewd tonight and bring any precip to an end by around sunrise. Skies to continue clearing as the trof moves ewd, and another cold and dry December day will round out the standard work week.
The rip current risk may increase on the Gulf Coast this weekend, as a cold front turns winds to the northwest.
539 PM CST Thu Dec 7 2017 Upper level low pressure trough transitioning through at the start of the TAF forecast. /issued 224 PM CST Thu Dec 7 2017/ The slow-moving upper level trough that has brought precipitation to roughly the southern half of West Texas continues to shift slowly to the east and southeast, its axis along a line from northeastern Sonora across eastern New Mexico to the lower Missouri Valley. The cold start and a period of mid cloud will be more than offset by a rapid increase in thicknesses as the main upper trough accelerates quickly eastward.
A strong upper ridge will bring dry, or nearly dry, weather to Western Washington through next Thursday at least. A strong upper ridge remains over the Pacific Northwest this morning, with its 5860 meter high centered over southwest Oregon. Fog and freezing fog were limited to the most fog-prone spots this morning, mainly in the Puget Sound region and south interior lowlands, and it has largely dissipated for the day. 2 pm temperatures ranged from the upper 30s to the lower 50s.
Chattanooga Airport, TN 31 38 26 45 / 10 10 0 10 Knoxville McGhee Tyson Airport, TN 27 35 24 41 / 0 10 10 10 Oak Ridge, TN 27 38 24 41 / 0 10 10 10 Tri Cities Airport, TN 28 35 24 38 / 0 10 10 10 NC.
Enough moisture may arrive within a low level thermal ridge to produce stratus for Fri AM and possibly lingering into the afternoon. Overall, we are forecasting 1-3 inches with the higher amounts in ern WI. A 1 to 3 inch fluffy/powdery snowfall is forecast at this time, with the highest amounts in the far eastern portions of the area.
948 PM EST Thu Dec 7 2017 High pressure and drier air will build in tonight and Friday.
630 PM EST Thu Dec 7 2017 High pressure overnight and Friday.
A warmer day is anticipated with high temperatures warming into the low to mid 50s across the region. Further east, and away from the downslope conditions, temperatures will be cooler and generally in the 40s in locations in and east of Miles City/Broadus.
925 PM CST Thu Dec 7 2017 Had to make some drastic changes to overnight lows, as light winds clear skies and the ridge axis moving overhead has led to temps dropping like a rock late this evening, with optimal radiational cooling conditions. Models show some isentropic lift in the 285K-290K layer with this cloud deck behind the upper trough.
Northwest to west winds will keep driving temperatures down to the low 20s/upper teens. Expect a quiet and dry overnight as we remain in the dry slot ahead of an upper trough axis, and to the north of a persistent SW flow moisture stream. Some spots will be in the upper teens with some spots in the lower 20s. In fact, we'll be well below normal with highs only in the mid and upper 30s again tomorrow, and lows Friday night in the low to mid 20s.
656 PM CST Thu Dec 7 2017 Weak high pressure remains over the area with a progressive northwest flow aloft. Current surface analysis places weak trough stretching through the northern plains into the central Rockies, while high remains over the southern plains. Upper level analysis places ridge over the west coast with trough stretching from the Great Lakes into the desert southwest.
521 PM CST Thu Dec 7 2017 Water vapor imagery this afternoon was showing a well defined ridge situated over the west coast with a deep positive tilt trof extending from southeast Canada to the southern Plains. high pressure was in control over the western half of the CONUS. Models in good agreement that large scale flow will not be too progressive into and through this weekend with a mean ridge west/trof east with a series of vort maxes dropping into the upper/mid MS region.
Meanwhile, a cold front is stalled across the central Gulf of Mexico. Short Term Update - Winds will remain light and turn more southerly overnight as the western end of the ridge retreats further east and surface pressures fall ahead of the cold front in the Gulf of Mexico.
522 PM CST Thu Dec 7 2017 A secondary frontal boundary pushed through last night bringing our temperatures to the lowest of the year so far this morning with a stiff breeze and single digit wind chills. A weak elevated warm front will pass through overnight helping to keep winds between 5-10mph throughout the night and shifting to the W-SW.
Current surface analysis shows warm front over central SD, with milder air building in behind it. Upper level analysis shows broad trough covering most of the central and eastern US, with high amplitude ridge along the west coast. The warming trend will continue through the weekend as ridge along the west coast nudges eastward.
1008 PM EST Thu Dec 7 2017 High pressure overnight and Friday.
High pressure will keep clear and dry weather in place the rest of this week and through the weekend. An upper level ridge remains parked over the West Coast, bringing plentiful sunshine and above normal afternoon highs region-wide. Forecast models continue to advertise much of the same for the foreseeable future as high pressure won't be going anywhere anytime soon. While the upper level ridge remains stationary over the West Coast, expect the dry conditions to prevail. Smoke from the southern California wildfires appears to have gotten swept up in the ridge bringing high level smoke to the area. SFO Bridge Approach. Strong high pressure will dominate the weather pattern through the forecast period. Lighter, variable winds will prevail for areas protected by coastal ridges, such as offshore of the Santa Cruz Mountains, Big Sur, and the Sonoma coastline.
549 PM MST Thu Dec 7 2017 Updated forecast to expand the freezing fog advisory into the upper Snake Highlands with satellite showing low stratus and fog over much of that area as well.
653 PM EST Thu Dec 7 2017 Aviation Lingering lake effect snow showers will taper off late this afternoon and evening as high pressure briefly builds in tonight into Friday.
Very few changes are in store for Northwest California for quite a while, as high pressure is firmly entrenched along the west coast. As a result, valleys will remain cold and will continue to fall below freezing in many areas, especially east of South Fork Ridge. Ridges will be a bit more mild, likely the 40s and even 50s, as these areas will be above the valley inversion and exposed to breezier east winds. A persistent strong ridge will continue to result in VFR conditions and clear skies at all terminals through tonight.
Expect the wintry mix to continue near CLL and UTS through 03Z and provide periods of IFR to MVFR ceilings and visibilities before shifting south between 03-06Z as drier air arrives and an upper level jet streak slides across the lower half of region from Mexico. /ISSUED 358 PM CST Thu Dec 7 2017/ Challenging forecast tonight with possibility of wet snow for many areas and freezing temperatures for northern half of the area. light rain is occurring with temperatures mainly in the lower to mid 40s. Sounding from UH and StormGeo showing mostly subfreezing conditions aloft with freezing level only 2500 feet. Surface wet bulbs also generally well above freezing attm. At the same time upper trough and jet streak with associated lift progged to migrate cross the area.
Area remains under a deep/cold mid-level trough extending from Hudson Bay Canada through WI into the central/southern Plains.
622 PM EST Thu Dec 7 2017 High pressure and drier air will build in tonight and Friday.
701 PM CST Thu Dec 7 2017 Upper level flow was out of the north with a high amplitude ridge over western North America and trough over eastern Canada. Clouds and light winds to keep temps up overnight across the area with lows expected to be in the teens, warmest in the west and south and cooler in the north and east. Ahead of the system westerly SFC winds will again allow a quick temp rise into the upper 20s and even lower 30s along the valley and to the west before the cold front pushes through and winds shift to the north. Flurries and light snow is expected along and or in the wake of the cold front with some strong gusts from the NW.
423 PM MST Thu Dec 7 2017 Current surface analysis shows warm front over central SD, with milder air building in behind it. Upper level analysis shows broad trough covering most of the central and eastern US, with high amplitude ridge along the west coast. The warming trend will continue through the weekend as ridge along the west coast nudges eastward.
Upper level flow was out of the north with a high amplitude ridge over western North America and trough over eastern Canada. Clouds and light winds to keep temps up overnight across the area with lows expected to be in the teens, warmest in the west and south and cooler in the north and east. Ahead of the system westerly SFC winds will again allow a quick temp rise into the upper 20s and even lower 30s along the valley and to the west before the cold front pushes through and winds shift to the north. Flurries and light snow is expected along and or in the wake of the cold front with some strong gusts from the NW.
543 PM CST Thu Dec 7 2017 1031 mb high pressure over central KS and ridging into the mid MS and lower Ohio river valleys has clear skies over central IL at mid afternoon.
/issued 316 PM CST Thu Dec 7 2017/ This afternoon light rain and drizzle continues across much of the area with temperatures from the lower 40s in the rain to to lower 50s outside the rainfall. As far as accumulations the best guess with the deterministic forecast is for possible accumulations of less than 1 inch where temperatures will be near freezing or snowfall rates will compensate for warmer temperatures. Another concern is temperatures going below freezing across northern portions of the area. Any water on area bridges may have a chance to freeze across east Texas and West central Louisiana despite precipitation coming to an end. Temperatures will warm to above freezing across all areas by late morning Friday and precipitation will be coming to an end as well.
315 PM MST Thu Dec 7 2017 Current surface analysis shows warm front over central SD, with milder air building in behind it. Upper level analysis shows broad trough covering most of the central and eastern US, with high amplitude ridge along the west coast. The warming trend will continue through the weekend as ridge along the west coast nudges eastward.
815 PM EST Thu Dec 7 2017 A cold front continues to drift south over central and southwest Florida tonight and on Friday.
However, the lower atmosphere is quite dry and most of the precipitation on radar is likely not reaching the ground. Some light echoes noted on KSHV radar likely not reaching the ground in most locations, as the dry air continues to deepen ahead of the approaching upper trof. Despite freezing temperatures expected tonight, any precip that is able to fall will be too light to accumulate. Freeze warning remains in effect for tonight, as we haven't seen widespread freezing temperatures across the region for over a month. Upper trof will continue ewd tonight and bring any precip to an end by around sunrise. Skies to continue clearing as the trof moves ewd, and another cold and dry December day will round out the standard work week.
Did increase the valley temperatures a touch in the far southeast, given the current higher dew points and more gradual cold air advection in the low levels. A cold front is pushing across southeast Kentucky this afternoon with cooler and drier air working in from the northwest behind this front. The present frontal boundary will stall well to our southeast tonight with an area of low pressure tracking northward along this boundary tomorrow. With dewpoints running in the low to middle teens, combined with expected clearing, we should see temperatures tank Friday night. Lows in the valleys could easily reach the mid to upper teens with ridges holding in the lower 20s.
Snow packed roads are going to get icy as well as bridges. Temperatures will struggle to get above freezing until probably 9 am with all the snow on the ground there. AMDAR soundings (HOU/IAH) all showing the transition over to freezing around 1700ft with freezing profile above. Temperatures are forecast to remain at or above freezing to the south of the advisory including the Houston Metro area so the snow should melt on contact with roads. Expect the wintry mix to continue near CLL and UTS through 03Z and provide periods of IFR to MVFR ceilings and visibilities before shifting south between 03-06Z as drier air arrives and an upper level jet streak slides across the lower half of region from Mexico.
The front is expected to stall along the coast early Sunday before washing out and giving way to a return to much warmer air during the day on Sunday.
900 PM CST Sat Feb 17 2018 The main update with the forecast tonight is to account for a farther south progression of a cold front than previously advertised. Onshore winds will strengthen Sunday afternoon as low pressure over eastern Wyoming deepens.
Slightly less active weather is expected tomorrow as the frontal boundary continues to weaken and high pressure becomes more prom- inent. The persistent upper troffing to our west should allow for a series of disturbances to move across the region these next several days.
If fog were to develop, would need to keep in mind that surface temps will be near or below freezing in many locations by morning. High pressure scoots rapidly east Sunday allowing winds to become more southerly.
603 PM CST Sat Feb 17 2018 Clouds are slowly clearing from west to east this afternoon with the clearing line just moved through the Highway 65 corridor as of 3 pm. A large upper level trough will develop and dig across the western U.
Slightly less active weather is expected tomorrow as the frontal boundary continues to weaken and high pressure becomes more prominent. The persistent upper troffing to our west should allow for a series of disturbances to move across the region these next several days.
535 PM CST Sat Feb 17 2018 Expect some improvement in conditions this evening, as high pressure passes by to the north of Arkansas.
Chattanooga Airport, TN 39 65 53 69 / 60 20 50 30 Knoxville McGhee Tyson Airport, TN 37 62 49 68 / 70 10 60 40 Oak Ridge, TN 37 62 48 67 / 50 10 60 40 Tri Cities Airport, TN 34 61 42 68 / 80 10 60 40 TN.
As our CWA will be in the transition zone between the lowest RH values and the area of higher wind speeds, some of the area within the Red Flag Warning may be a bit marginal in meeting the hard criteria. But after coordinating with surrounding offices and SPC, have decided to include the marginal areas in the Red Flag warning since those areas are currently covered by a critical Day 2 FWX outlook area and they could very easily meet critical fire weather criteria, even if only for a brief time, and that it would be better if those areas were covered by the highlight since such warm temperatures with corresponding low RH values and gusty winds are not a regularly occurring event in mid February.
High pressure currently over the central US will slowly drift south and east of the region by Sunday morning. Arctic high pressure, currently over Alaska, has strengthened to around 1044 mb. This high will move south into nrn Neb late Sunday afternoon.
934 PM CST Sat Feb 17 2018 Latest surface analysis indicates high pressure centered over Arkanas this evening with light and variable wind across much of our forecast area. Deepening trough through the Plains will result in veering low level wind overnight then strong southerly wind Sunday.
The low clouds will remain across the area on Sunday, with ceilings improving to MVFR at the southern terminals by 19Z. Overnight tonight, we should see lee trough developing to the west, which will shift winds around to the southeast, with low level moisture surging north. We kept high temperatures tomorrow a few degrees cooler than today across the south due to increased cloud cover, but we should climb into the 70s.
High pressure will ridge across the area through the period. Lows tonight will be in the mid 50s to mid 60s, and highs Sunday will be generally in the lower to mid 80s.
A cold front will move through the area Sunday night, bringing big changes to the weather forecast. At the same time, low-level moisture will remain trapped below 800mb, which will bring a good chance for drizzle and freezing drizzle to the area.
Couple of Periods of Freezing Drizzle and Light Snow Sunday Forecast concerns over the next few days will be temperatures, winds, precipitation type and coverage, and if headlines will be needed. Visible satellite imagery shows a few patchy cloud spreading into northeast Nebraska about 1500 to 3500ft and some cooler temperatures in the 30s. This will feed into an area of low pressure from South Dakota into Minnesota with accumulating snow for those regions.
Sunday, upper flow transitions to a more southwesterly regime which will activate the lee trough. Along with high pressure sliding east and strengthening, return flow will be on the increase along with a LLJ overnight into Sunday morning.
658 PM EST Sat Feb 17 2018 Low pressure will move off the coast by midnight.
The low for tonight, with gradual partial clearing, will be in the 30s.