Aikyam-Lab/Synoptic-Bench huggingface dataset:
/issued 1002 AM CST Fri Nov 29 2019/ Boundary layer moisture convergence situated along the coastal counties in close proximity to the returning warm front has continued to produce scattered showers in a narrow band this morning. This band of showers is expected to slowly diminish by late morning/early afternoon as the warm front lifts north of the CWA and boundary layer convergence weakens. Likely less fog tonight due to the warmer temps and stronger gradient flow from the S/SE. SCEC conditions are expected to develop by the afternoon across most of the coastal waters as the gradient continues to tighten with the warm front lifting rapidly northward.
1043 AM EST Fri Nov 29 2019 High pressure will prevail with dry weather through Saturday.
Elevated instability has steadily increased through the day and this trend will continue through the overnight hours as upper low moves into the Plains. Currently the sfc warm front remains across NE TX confining sfc based instability south of the region. This feature will also continue to lift northward, and it is likely portions of far SE OK realize the system warm sector late tonight through early morning Saturday before winds veer ahead of the approaching cold front. A brief lull in winds is expected by early evening before the polar cold front associated with the larger storm system moves into the region.
As the upper low lifts east through Saturday, strong winds will develop across central and eastern Kansas into western Missouri.
819 PM CST Fri Nov 29 2019 Sent out a quick update to change the timing a bit from freezing drizzle to snow. With the storm track being a little further south, the snow has been reluctant to develop on the northern end, therefore freezing drizzle continues. So, have backed off some on ice aloft needed for snow development, and kept the chances for freezing drizzle going for most locations until after midnight. The main change for the early evening update was to significantly increase precipitation chances for this evening as multiple locations are reporting freezing drizzle which is creating very slippery conditions.
The forecast will continue to be cloudy as we transition from an upper level ridge to more southwest flow this evening and then continue with southwest flow through Saturday evening/night.
A general improvement in ceilings will happen Saturday afternoon as a ridge slides over our forecast area.
807 PM EST Fri Nov 29 2019 Some isolated patchy ground fog possible near dawn, but otherwise lows on track to fall into the lower 50s north to the mid 50s- around 60 central and south.
Chattanooga Airport, TN 47 64 51 61 / 10 30 100 10 Knoxville McGhee Tyson Airport, TN 45 61 51 59 / 30 30 100 40 Oak Ridge, TN 44 59 50 58 / 30 50 100 40 Tri Cities Airport, TN 42 55 48 58 / 40 90 100 80.
Tonight, we will see a return of quite a cocktail of freezing and non-freezing precipitation in the form of rain and drizzle. Continuing the High Wind Warning. May have to extend the High Wind Warning's duration, as some of the local high-res guidance is dragging the event out longer. Less concerned with blowing snow as much of the snowpack has had additional non-freezing and freezing precip in sporadic intervals throughout today.
The Coastal Plains, south of the warm front, and the Rio Grande Plains are the only areas without visibility restrictions. The warm front is still slowly moving further inland from the Coastal Plains. With warm air advection behind the warm front, paired with overcast skies, overnight temperatures will increase slightly before staying almost constant overnight. Tomorrow will be quiet warm as we heat up before the next cold front has a chance to clear everything out Saturday afternoon.
There is a broad trof over the intermountain west. There is weak high pressure off the Washington/Oregon coastline, and west of that is another trof with a developing low pressure system.
Overnight lows to settle in the mid to upper 50s across the region, except in the low 60s along the Martin County coast.
Widespread LIFR/IFR conditions across the region this evening will continue overnight ahead of approaching short wave currently located over NM, as large area of isentropic lift over warm front across far N TX continues. Elevated instability has steadily increased through the day and this trend will continue through the overnight hours as upper low moves into the Plains. Currently the sfc warm front remains across NE TX confining sfc based instability south of the region. This feature will also continue to lift northward, and it is likely portions of far SE OK realize the system warm sector late tonight through early morning Saturday before winds veer ahead of the approaching cold front. A brief lull in winds is expected by early evening before the polar cold front associated with the larger storm system moves into the region.
During the evening areas near and N of Route 422, the Laurel Highlands, and the WV/MD ridges should see a changeover to freezing rain as surface temperatures drop to and slightly below freezing.
Wet and cloudy conditions will persist through Saturday morning as a low pressure system deepening over the eastern Rockies and central high Plains moves into our region. At the surface a warm front will advance northward from eastern Oklahoma into the MO Ozarks during the overnight hours, raising temperatures and dewpoints into the 50s. Rain should end during the mid to late morning hours on Saturday as the cold front moves across the region.
Warm frontal boundary is stretching along southeast Texas into the northwest Gulf.
Scattered showers will continue east into the morning hours on Saturday as the upper ridge axis steadily moves east. Temperatures are trending slightly warmer than previously forecast, so made minor adjustments to hourly temps.
Conditions should begin to improve from west to east late tonight with KCDS expected to hold onto the low CIGS the longest. /issued 218 PM CST Fri Nov 29 2019/ As expected, surface ridging held firm today with dense fog persisting until the early afternoon. However, winds will quickly turn to the southwest and then to the west early Saturday morning due to a Pacific cold front moving through the region. The upper level trough axis will pass overhead during the day on Saturday which will bring strong subsidence to the region. The aforementioned Pacific cold front may keep us from mixing up to 700mb but winds between 800 and 750mb are still around 50kt.
639 PM CST Fri Nov 29 2019 The main change for the early evening update was to significantly increase precipitation chances for this evening as multiple locations are reporting freezing drizzle which is creating very slippery conditions.
The weather system departing across Arizona tonight will be followed by a ridge of high pressure and tranquil weather for most of the region through the weekend.
323 PM MST Fri Nov 29 2019 Below normal temperatures are expected Saturday in the wake of the low pressure system that brought wet and windy conditions to the Desert Southwest.
309 PM CST Fri Nov 29 2019 Current water vapor imagery shows a 534 dam low over N Nevada and a deep negatively tilted trof sweeping through the southwestern CONUS with diffluent flow over the Central Rockies. After the front passes from W to E, dry air and light winds will cause temperatures to plummet tomorrow night into the low to mid 30s.
ABM Chattanooga Airport, TN 64 51 61 37 45 / 60 90 10 10 0 Knoxville McGhee Tyson Airport, TN 61 51 59 37 42 / 50 90 40 30 30 Oak Ridge, TN 59 50 58 35 42 / 60 90 40 30 30 Tri Cities Airport, TN 55 48 58 35 40 / 70 90 80 70 70.
745 PM PST Fri Nov 29 2019 Much cooler temperatures and dry weather will be in place through Saturday.
The trough of low pressure responsible for our winter weather covers the entire western United States this evening. A cold front has pushed east of northern AZ, and while winds behind this passage are not be as strong as along the front, they will still remain quite gusty this afternoon.
A cold front will move southeast across the area tonight with cooler temperatures Sunday. Gusty northwest winds will make it feel even cooler as wind chills will star the day in the 20s and 30s.
/Tonight through Sunday/ Warm front ahead of schedule and that may come out in the wash with the new 00Z runs and of course the cold front moving over our area on Saturday. Surprisingly the winds have dropped off some of the gust from the south as the low clouds fill back in overhead. Much cooler high pressure slowly arriving during all of our Sunday from midnight tomorrow becoming gusty from the NW with Lake wind criteria expected through the afternoon on Sunday after lows in the wind chilly 40s, our highs will keep to a range in the 50s.
A low pressure system will move through the region tonight. By Sunday, another low pressure will approach the California coast and stall out for early week.
Wind gusts of 55 to 65mph are likely in the High Wind Warning areas for this afternoon/early evening.
Can't rule out some isolated showers between now and late afternoon Sat, but for simplicity sake, will not mention much in the TAFs until the cold front approaches CLL ~22z and the coast closer to midnight. /ISSUED 1036 PM CST Fri Nov 29 2019/ Sea fog has not been an issue so far this evening and have no logical reason for this absence of fog other than the winds are southeast (compared to a more cooler easterly fetch last night). Another very warm, overcast and humid day tomorrow as we fall just downstream of the next cold front. Thus, December will actually start off on a cooler note as Sunday morning's minimum temperatures register in the mid/upper 40s north to lower/mid 50s closer to the coastline.
Given the cooler model solutions today, have backed off some on temperatures through Saturday. As the low continues to propagate eastward, these winds and wrap-around snow chances will decrease rapidly throughout the day Sunday.
No rain is expected in the near term thanks to persistent ridging aloft. Upper ridging will be in place Saturday allowing dry and mild weather for Saturday with highs in the mid 70s. That ridging flattens Saturday night ahead of the next cold to move through Sunday. Lows Saturday night will be in the low 60s with low 40s for lows Sunday night.
At the sfc a shallow cool and stable layer remains but terrain effects have mixed some of the warmer air down across NW AR and SE OK, where temps/dew points have jumped into the mid 50s-lower 60s with gusty south winds. Still appears that the true warm sector remains just south of the Red River with broad corridor of 65-70 dew points, but this warmer intrusion may increase the risk of a sfc-based storm farther north within a strongly sheared environment. Otherwise the overall forecast thinking remains about the same as incoming 00z model data supports continued shower and thunderstorm development within moist axis with likely increase in coverage by late tonight with the approach of Pacific cold front.
Fortunately, most areas warmed to freezing or above, thus the impacts have been minimal today. Northeast NE was still 32, with an area of heavier rain up to one quarter inch in an axis from Albion to Wayne, but numerous reports from spotters, law enforcement, and the public have indicated that the rain was not freezing on roads, despite the cold temperatures. , moisture could wrap around on the back side and fill back in across the remainder of eastern NE, which will actually be under the closed cold core of the upper low. With the colder air wrapping around the low, this would be a a rain/snow mix in northeast NE.
Surface temperatures are currently around freezing. They should climb above freezing as this light precipitation moves in during the day. Trends in the recent model runs support a slight southward shift to the impactful freezing rain. Thus the row of counties just south of the current Winter Weather Advisory are now expected to see a steady period of freezing rain tonight. Impacts may be limited as much of the area will see above freezing temperatures and the colder air wrapping around the storm system is not that cold.
/issued 303 PM CST Fri Nov 29 2019/ (Tonight through Saturday) Isolated shower and thunderstorms possible tonight mainly in eastern zones as upper trough moves east. Winds were finally shifting to the south this afternoon as the warm front moves through, but with a moist boundary layer in place, patchy fog possible.
Upper ridging will remain in place but will begin to deamplify by this evening as an upper trough and surface cold front moves into the Lower Mississippi River Valley.
Below normal temperatures are expected Saturday in the wake of the low pressure system that brought wet and windy conditions to the Desert Southwest. High pressure will build across the southern Rockies Sunday, resulting in a warming trend and a return to above normal temperatures.
A dry upper level trough will continue to reside over the region through Saturday.
935 PM PST Fri Nov 29 2019 Much cooler temperatures and dry weather will be in place through Saturday.
Satellite imagery showing upper low along the OR/ID border near Weiser this evening. While showers continue to wrap around the low, coverage and intensity has decreased with the loss of daytime heating.
320 AM EST Sat Nov 30 2019 Broad upper level ridging extends from the northeast Gulf of Mexico northward through the Ohio River Valley and into Ontario Canada.
/issued 807 PM EST Fri Nov 29 2019/ Some isolated patchy ground fog possible near dawn, but otherwise lows on track to fall into the lower 50s north to the mid 50s- around 60 central and south. Light winds and seas through early Sunday, then winds increasing ahead of a cold front.
Much of the snow will be concentrated along the Continental Divide in southwest Montana, where southeast flow above the ridges will continue to feed the deep dendritic snow producing layer. Clouds are anticipated to break up a bit by this afternoon, with temperatures noticeably warmer than recent days for much of the Northern Rockies through the weekend.
And a Pacific Cold Front will also become more apparent around daybreak with flow veering to the west-northwest with cold advection prevalent throughout the day. But we may adjust the High Wind Warning further south if the trends indicated above for 50+ knots near the top of the mixed layer continue in the next few hours. Cooler air will continue advecting overnight, and Sunday will see another below normal temperature day with much lighter winds, though still breezy over the northern Rolling Plains. Beyond Sunday, little has changed as an upper level ridge will bring near-normal temperatures for most of the early to mid part of the week.
412 AM MST Sat Nov 30 2019 Impressive lee side cyclone developing this morning in the High Plains with all three distinct conveyor belts showing up nicely in water vapor. Temperatures in the wake of this system will be quite chilly and with cold air in the low layers locked in by WAA and subsidence aloft. This land feature looks like it will absorb or deflect much of the moisture with a broad ridge in place over the Intermountain West.
Passing upper level trough will allow for some gusty west winds to mix down to the surface, mainly north of a San Angelo to Brownwood line. Not terribly warm today so may not maximize heating like we might on a warmer day, but still looking at gusty west winds at least into the 15 to 25 mph range and probably stronger at times. Otherwise, sunny and drier conditions in store with highs in the low to mid 60s north of I-20, to the mid 70s across the southeast counties in the Hill Country. Much cooler tonight with the dry air mass in place with overnight lows in the 30s.
Strong llvl WAA is occurring out ahead of the low this morning. Evidence of this already showing up on regional radar mosaics early this morning as a decent e/w oriented band of moderate to heavy snow(possible 1-2 inch/hr accum) working nwd between the highway 14 and 212 corridors in our CWA. This would promote a round of some freezing drizzle or a wintry mix for a time primarily the latter half of the morning into the afternoon.
304 AM MST Sat Nov 30 2019 The latest MRMS Reflectivity showing the upper low circulation over central Nebraska with some wrap around moisture still producing showers over the far northeast corner from Logan County eastward. Strong winds will continue in the afternoon but stronger gusts should start shifting more the the higher foothills by that time. Will keep the timing of the highlights in place at this time.
336 AM CST Sat Nov 30 2019 A strong upper low rotating across the Rockies onto the plains this morning will continue to roll east reaching the MS valley by Sunday. As it does a ridge will build across the west and result in mild wx for the region.
At the surface, a warm front has surged northward to near I-40 across southeast Oklahoma with a Pacific cold front across northeast Oklahoma into south-central Oklahoma. The shower and thunderstorm activity is expected to continue in advance of the cold front overnight into Saturday morning as the front moves to the east. The showers and thunderstorms are expected to exit the area by mid-morning as the cold front exits the region. Temperatures will be noticeably colder on Sunday as a reinforcing cold front is expected to move through eastern Oklahoma and western Arkansas Tonight.
/issued 336 AM CST Sat Nov 30 2019/ A strong upper low rotating across the Rockies onto the plains this morning will continue to roll east reaching the MS valley by Sunday. As it does a ridge will build across the west and result in mild wx for the region.
Broad upper level ridging extends from the northeast Gulf of Mexico northward through the Ohio River Valley and into Ontario Canada.
521 AM CST Sat Nov 30 2019 Early morning GOES water vapor imagery showed a deep upper low over western Nebraska. The upper low will track east across Nebraska today, gradually deepening and reaching south central Iowa by midnight. The Midsouth will remain in the low level warm sector, south of a frontal occlusion point likely near St Louis at 18Z/Noon CST. The upper low center will move to near Chicago by midday Sunday.
A cold front moves across the sites this afternoon turning the flow to north-northwesterly. At KDRT, LIFR conditions erode to FEW VFR mid morning as the cold front moves across that site with southeasterly winds at 5 KTs shifting to northwesterly at 7 to 15 KTs. An upper level trough is moving across the Rockies and the flow over Texas is southwesterly. At the surface, a warm front has moved north of our CWA and winds are from the southeast. A cold front is stretched from the Panhandle border with Oklahoma to near Dryden.
Sfc map at 08z showed a 992MB low centered across southwest NE with a diffuse warm front extending southeast across the area. The effective dry slot will push sfc dewpoints down into the 20s into parts of central KS this afternoon before the pacific cold front surges southeast and actually acts to increase dewpoints somewhat later this afternoon at least for parts of central KS. Minimum relative humidities should fall into the 30-40% range with the lowest in the Dickinson/Morris/Geary CO vicinity.
Warm and Dry Through Sunday, Followed By a Strong Cold Front.
502 AM CST Sat Nov 30 2019 Chances for SHRA/TSRA will become likely this morning as a cold front moves into the state from the NW. Today Through Sunday Night Temps continue to warm across the CWA early this Sat morning as the warm front to the south lifts north towards the state. Expect this warm front to lift north across the CWA this morning ahead of an approaching cold front. This will allow temps to warm into the 60s to near 70 before the cold front moves SE into the CWA by around midday across the NWRN counties. Expect the aforementioned cold front to move SE through the CWA by late this afternoon into the early evening hrs before exiting to the SE tonight. especially in the higher terrain.
With temps mostly above freezing, treacherous travel is limited. Temperatures closer to freezing in the northern CWA could create slippery spots on area bridges. As the powerful closed low pressure system responsible for these winds wraps colder air into the area, rain will change to snow.
An expansive region of high pressure stretching from Eastern Canada southward into the Southeast United States, and down the Sunshine State today will slide into the western Atlantic Ocean and splinter tonight. The southern portion of the anticyclone will extend a ridge axis across the southern half of the Sunshine State and into the Straits of Florida by late Sunday.
An upper level trough is moving across the Rockies and the flow over Texas is southwesterly. At the surface, a warm front has moved north of our CWA and winds are from the southeast. A cold front is stretched from the Panhandle border with Oklahoma to near Dryden.
/issued 521 AM CST Sat Nov 30 2019/ Early morning GOES water vapor imagery showed a deep upper low over western Nebraska. The upper low will track east across Nebraska today, gradually deepening and reaching south central Iowa by midnight. The Midsouth will remain in the low level warm sector, south of a frontal occlusion point likely near St Louis at 18Z/Noon CST. The upper low center will move to near Chicago by midday Sunday.
Wood/Portage/Waushara will be okay as sub freezing temps will result in a mix of SN/FZDZ/-FZRA so travel will likely become hazardous. East of there, temps are a little warmer so precip will likely be a mix of SZ/DZ, which likely won't have as much impact on travel.
Dry high pressure dominates area. A cold front approaches the waters on Sunday with rainshowers likely.
Cold air advection will still allow temperatures to fall into the lower 20s in the southwestern Texas Panhandle and lower 30s in the southern Rolling Plains. Upper ridging will build in for the first half of the week leading to continued dry conditions.
Otherwise, warmer and sunny this afternoon with highs in the upper 50s and 60s. A cold front will move southeast across the area tonight with cooler temperatures Sunday. Gusty northwest winds will make it feel even cooler as wind chills will star the day in the 20s and 30s.
The cold front still sits to our north and has been crawling as of this morning. By the time the front eventually makes it through the area, winds will shift out of the north, bringing in cooler and much drier air. Tomorrow will be clear and cooler with highs in the 60s and tomorrow nights lows in the mid to upper 30s, reminding us briefly, that it is December.
A period of more widespread/moderate rain will likely accompany this strongly forced boundary, with perhaps just enough theta-e ridging and strong enough forcing to generate an isolated rumble of thunder and heavier convective elements. System dry slot will provide a lull in shower chances/coverage Sunday morning with temps likely edging up into the low-mid 40s for most locations. Stacked/closed low, with 500 mb temps down to near -30C, then follows into the local area Sunday afternoon- evening with numerous showers and cooling temps anticipated.
Precipitation could start out as a little snow Sunday morning before changing to rain in the lowlands.
A weak upper ridge will bring dry conditions to southeast Oregon and southwest Idaho this afternoon.
Ridging builds in tomorrow, followed by southwest flow aloft Sunday night with the arrival of a Pacific jet and Atmospheric River.
Mid/High level clouds increase Sunday afternoon ahead of a cold front that moves south through forecast area Sunday night.
230 PM CST Sat Nov 30 2019 Main forecast concern today is the ongoing gusty west to southwest winds and the nonzero potential for another round of advisory criteria gusts tomorrow following tonight's cold frontal passage. Warmer and much drier conditions have prevailed areawide for much of today, resulting from the arrival of the strong downslope west to southwest flow behind last night's frontal passage. A much stronger cold front will move through the area tonight, bringing another round of strong winds from the northwest and much cooler temperatures.
Areas of light freezing drizzle and snow are still possible KXWA-KMOT this afternoon with IFR conditions, turning to all snow during the late afternoon.