Aikyam-Lab/Synoptic-Bench huggingface dataset:
Surface wise, a large ridge of high pressure covering the entire eastern United States and down the Sunshine State. With that said, the exiting mid and upper level disturbance will enhance large scale subsidence along with additional drier air to filter downward into the low levels later this afternoon.
However, some bridges and overpasses may have cooled off quickly enough last night to allow some ice to develop. So our main message is to be prudent and allow for some extra time for travel this morning, and be cautious on bridges and overpasses. At this hour we still have snow occurring across the higher north/east facing slopes of the Beartooths and Big Horns, and stretching out east across Powder River and Carter Counties. Most of the upper dynamics with this system have moved south and east and trough axis will exit our southeast corner early today.
High pressure will remain over the West Coast keeping the weather dry for the next several days. Cold and dry air in the wake of a frontal system will allow for the widespread frost and freezing temperatures over the next several nights and mornings. Temperatures continue to plummet overnight with several SJV and Kern County desert locations below freezing as of 230 am. Water vapor imagery shows drier air dropping southward into California as north the northeast flow around the periphery of a strong Western Canada high pressure system brings cold and dry air into the region.
Strong high pressure aloft will cover the western states through the week.
Winds will swing around to the west then northwest today as a pacific-type trough moves across the area. This will be followed by a cold front this evening which will bring a period of gusty northeast winds. Little to no accumulation is expected, and with surface temperatures likely at or above freezing, no impacts are anticipated on the roadways.
Surface ridging moving east of the Appalachians will allow for south to southwesterly winds to develop with gusts up to 15kts at CHA and TYS this afternoon.
The wind has kept current temperatures mainly in the lower to mid 40s through the valley while readings in the mountains are chilly with mainly teens and 20s. The strongest north winds in the Central Valley are expected today with gusts around 40 mph while easterly gusts are expected to top out tonight and early Tuesday across the northern Sierra with local gusts of 60 mph or greater possible along the crest and exposed ridges. Enough breeze is expected to linger overnight to keep much of the valley above freezing. However, winds will likely decrease enough over the northern San Joaquin Valley and along the eastern edge of the southern Sacramento Valley for freezing temperatures to occur there early Tuesday.
A dry cold front will finish moving through northern Arizona this morning.
647 AM CST Mon Dec 4 2017 Starting to get some freezing rain at Jamestown and have added a period of freezing rain in the James River Valley this morning. As the main low/trough shifts through southern ND and northern SD today, large scale ascent will increase and eventually overlap a strengthening low level frontogenesis field mainly across the James River Valley.
The low clouds will break up early this afternoon, and then mainly VFR through tonight. A cold front will move south across the area tonight, with gusty north winds behind the front. For tonight, the weather will be a little more active as a cold front moves south across the area, around the I-20 corridor by 03Z, along a San Angelo to Brownwood line by 06Z and south of the I-10 corridor or by 11Z. Expect gusty north winds behind the front and much cooler temperatures. Also, scattered showers and a few thunderstorms will be possible east of a Brownwood to Junction line due to weak mid to upper level ascent and the cold front.
Currently they vary between 20s where the clouds have failed to generate, to low 40s in the Watertown area, but as the winds increase and we get mixing/cold advection, they should stall in the low 30s (generally below freezing). Suspect 1-3 won't cut it, but the higher amounts may - so will leave the headlines in place which matches that line of thinking. Upper low pressure troughing remains over much of the central and eastern U.
419 AM PST Mon Dec 4 2017 Strong high pressure will build over the Pacific Northwest today and persist through the week.
Cooler near normal temperatures are also expected today.
Breezy south-southeast winds today in advance of an approaching cold front. There will be a slight chance for showers or an isolated thunderstorm through midnight tonight, and then rain chances will quickly increase for the northwestern half of the forecast area as the approaching cold front moves in.
WV imagery indicates a strong upper level trough of low pressure moving eastward across the Colorado Rockies. Near the surface, a strong cold front is pushing southeast across southwest and central Kansas.
Strong high pressure aloft will remain in place over the western states through the week. An upper trough remains in place over Utah this morning, but will slowly slide east of the area throughout the day. This cold air which arrived in conjunction with the upper trough axis helped increased shower activity late last evening. With the trough axis continuing to head east out of the area and temperatures beginning to warm aloft, showers will gradually decrease during the late morning through afternoon hours and end by evening as a ridge starts to build into northern Utah. For these areas, max temperatures are only going to be a few degrees warmer than the current morning temperatures. With the ridge continuing to build into Utah tomorrow, the cold air will become trapped in the valleys as inversions develop.
an upper level storm system is currently spinning over Wyoming with a trough south across Utah to western Colorado. the upper system will continue to push east through this afternoon with the trough sagging south across Colorado. Where exactly the ridge/trough axis sets up/evolves with time will control how cold we get.
401 AM MST Mon Dec 4 2017 Overnight water vapor imagery showed a compact but intense upper level low pressure system tracking east across central WY. Surface cold front which moved through the CWFA was located from eastern SD through western NE and central CO. 00Z short range model/ensemble solutions are in good agreement with the progressive nature of the WY upper level low today.
A strong cold front with a gusty northeast wind will blow through the area overnight. /issued 330 AM CST Mon Dec 4 2017/ One more day of much above normal temperatures Monday with a strong cold front poised just north of the forecast area with mainly zonal flow aloft with low level thermal ridging in place. It will turn much colder tonight and Tuesday as a large upper level trough amplifies across the western half of the nation and sends a strong cold front through the forecast area.
In addition, breezy east winds are expected along ridges Monday into part of Tuesday. An amplified ridge extended northward across the northeastern Pacific toward NWRN Canada Monday morning. Though any exposed ridge in NWRN CA could experience gusty conditions, the strongest winds are forecast to occur in SERN Mendocino county. This is supporting subfreezing temperatures for many area valleys early Monday morning.
Freezing low temperatures are expected across much of the region through Tuesday night. The main weather concerns the next couple days will be continued strong north winds along the lower Colorado River Valley and overnight temperatures near or below freezing of the region.
528 AM EST Mon Dec 4 2017 Dry weather continues today behind departing high pressure, with a warmer afternoon. A cold front brings rain late tonight and Tuesday. Warm advection ahead of the approaching pattern-changing cold front will provide high cloudiness of varying thickness today. Low pressure will become vertically stacked as it rides across the western Great Lakes and into Ontario. The cold front is still progged to cross the area on Tuesday.
However, some bridges and overpasses may have cooled off quickly last night to allow some ice to develop. So our main message is to be prudent and allow for some extra time for travel this morning, and be cautious on this bridges and overpasses. At this hour we still have snow occurring across the higher north/east facing slopes of the Beartooths and Big Horns, and stretching out east across Powder River and Carter Counties. Most of the upper dynamics with this system have moved south and east and trough axis will exit our southeast corner early today.
929 AM EST Mon Dec 4 2017 High pressure continues to ridge over the area producing rain-free conditions and east-northeast winds.
At the surface, low pressure is located in eastern SD, and high pressure is settling into central MT. A secondary wave associated with the upper trough will slide through the area tonight, bringing another round of upslope snow to the northern Black Hills, and a reinforcing shot of cold air. Strong north to northwest flow will persist through the week as the main trof sets up across the eastern CONUS, and a ridge builds over the west. The very cold airmass will stick around through midweek, with below average highs in the lower 30s. Towards the end of the week, a gradual warming and drying trend is expected as the western upper ridge shifts eastward.
Additional lift associated with a very weak short wave trough over Coahuila may assist convective development.
430 AM CST Mon Dec 4 2017 As the main low/trough shifts through southern ND and northern SD today, large scale ascent will increase and eventually overlap a strengthening low level frontogenesis field mainly across the James River Valley.
925 AM EST Mon Dec 4 2017 High pressure will shift east of the area today. A strong cold front will move through the area Tuesday night.
Surface cold front is currently draped through central SD with the parent upper low emerging into the northern plains. These winds continue to be well advertised as on the high end of climatology in the ensembles. Shallow fog has developed ahead of a strong cold front and thus expect a couple hours of IFR/LIFR visibility/ceilings this morning.
Low temperatures tonight will fall into the upper 60s to the lower 70s. A strong cold front will surge into deep south Texas late Tuesday afternoon.
530 AM CST Mon Dec 4 2017 Water vapor imagery early today indicated an upper trough ejecting across the central Rockies. Will have to watch for the potential for a line of showers or low-topped storms to form later in the afternoon along the cold front as it sweeps eastward, especially across western Wisconsin. Strong low-level cold advection will quickly develop behind the cold front late today and this evening. There's good agreement in the general pattern evolution through the week into the weekend with a cold northwest flow pattern across the area in between an amplified western CONUS ridge and the eastern trough.
538 AM EST Mon Dec 4 2017 Near-term model guidance is coming in with more confidence in some light showers well out ahead of the cold front, moving into the Huntingburg, IN vicinity late this afternoon. That guidance shows a brief increase in coverage into the evening hours into the Louisville/Bowling Green area before that activity dissipates and the focus shifts farther west, closer to the cold front. A transition period will come today, after a sunny weekend, we will see increasing cloud cover and stronger winds ahead of a cold front progged to move through the region Tuesday. Rain showers will linger behind the front for a few more hours, but most models show a dry punch of air in the lower levels that should clear out further precip.
732 AM EST Mon Dec 4 2017 Dry weather continues today behind departing high pressure, with a warmer afternoon. A cold front brings rain late tonight and Tuesday. Warm advection ahead of the approaching pattern-changing cold front will provide high cloudiness of varying thickness today. Low pressure will become vertically stacked as it rides across the western Great Lakes and into Ontario. The cold front is still progged to cross the area on Tuesday.
For tonight, southerly flow in the low- levels will continue this evening. Big changes are in store early Tuesday morning for areas along and north of the Highway 90 corridor as a strong cold front moves in from the north. Much cooler temperatures, gusty north winds and an increase in rain chances are in store Tuesday as the strong front moves through.
A wind shift from the north/northwest, due to a cold front, will first impact GAG/WWR around 18Z. The cold front will move into central OK around 22-23Z. The cold front is currently in northwest Kansas and will move into the area a little before noon.
At the surface, low pressure is located in eastern SD, and high pressure is settling into central MT. A secondary wave associated with the upper trough will slide through the area tonight, bringing another round of upslope snow to the northern Black Hills, and a reinforcing shot of cold air. Strong north to northwest flow will persist through the week as the main trof sets up across the eastern CONUS, and a ridge builds over the west. The very cold airmass will stick around through midweek, with below average highs in the lower 30s. Towards the end of the week, a gradual warming and drying trend is expected as the western upper ridge shifts eastward. A strong cold front will cross the forecast area during the rest of the night.
Srly winds increasing today with a cold front set to move across area terminals this evening/tonight from NW to SE. Today Through Tuesday Night Quite the change taking place across not only Arkansas, but much of the nation as a deepening mid level trough makes its way across the Rockies and Great Plains this morning. The surface pressure gradient will tighten in response to the approaching cold front and winds will increase out of the south/southwest, but should stay below wind headline criteria. Timing and severe threat associated with the cold front hasn't changed.
High pressure will strengthen across the mid-Atlantic, and heights will rise as weak upper level ridging moves over the area. Weak coastal troughing will develop later today and a few coastal showers will likely develop offshore.
A weak short wave is passing us right now in the northerly upper flow ahead of a ridge building offshore. This trough may be disrupting fog over the Umpqua Basin and north coast, but otherwise will have little effect on our sensible weather. As soon as it gets out of the way (later this morning), the ridge will begin building strongly over us. Unseasonably strong upper level high pressure will then be in control of our weather through the remainder of this week and through the upcoming weekend. In addition to the low visibilities, temperatures are near freezing, so there is likely ice being deposited on some surfaces. However, as the ridge aloft strengthens and the air above us warms over the next couple of days, the fog will probably become more stubborn.
241 AM PST Mon Dec 4 2017 Strong high pressure will build over the Pacific Northwest today and persist through the week.
A coastal trough may keep winds backed a little more NE into the early afternoon over the Volusia/Brevard waters then becoming east by late in the day and SE by daybreak Tue.
413 AM MST Mon Dec 4 2017 Upper trough passing over Colorado this morning. Westerly winds have increased ahead of the cold front now entering southern Wyoming. Little change in the weather pattern over North America for the upcoming weak with a large upper level ridge along the Pacific Coast and an upper level low over the Great Lakes to Hudson Bay.
620 AM EST Mon Dec 4 2017 Dry high pressure over the region will move offshore late today.
Winter weather disturbance will move east of the state today allowing dry but cold conditions associated with high pressure to settle into the region.
The cold front is currently in northwest Kansas and will move into the area a little before noon.
These ceilings are likely to remain place ahead of cold front which will enter NE OK by early afternoon and clear western AR by late evening. /Issued 312 AM CST Mon Dec 4 2017/ A cold front is poised to sweep through eastern Oklahoma and western Arkansas late this Afternoon into Tonight. Temperatures will be much cooler on Tuesday in the wake of the cold front.
Another system moving through the larger scale trough late in the week may bring light snow to the area. Surface analysis late this morning shows strong low pressure over Minnesota and Iowa. A cold front was front stretching south across Eastern Kansas. Warm southerly gulf flow was in place ahead of the low across the Ohio Valley and Central Indiana. Models suggest Indiana will remain in the warm sector the rest of the afternoon as the cold front makes steady progress east. Expect widespread showers tonight as the cold front blasts through the area.
800 AM CST Mon Dec 4 2017 Have sent out a quick update to increase chances for freezing rain over the lower James River Valley. Starting to get some freezing rain at Jamestown and have added a period of freezing rain in the James River Valley this morning. As the main low/trough shifts through southern ND and northern SD today, large scale ascent will increase and eventually overlap a strengthening low level frontogenesis field mainly across the James River Valley.
Upper troughing will be over the area through Friday night, which combined with strong surface heating should help support scattered thunderstorms.
353 PM CDT Thu Sep 21 2017 A surface warm front will continue to lift north across the area tonight. The more concentrated activity looks to develop around/after 05z over central/northern MN/WI as the low level jet strengthens. Given the elevated dewpoints in the lower 70s, heat indices along and south of I-94 moderate into the 95 to 100 degree range. Given the breezy southerly winds, the true impact may be abated slightly, but Wet Bulb Globe temperatures still look to rise into the lower 80s across the metro area. The longer term concerns remain timing/evolution of the western conus trough and movement of the surface front.
This will help keep overnight temperatures much warmer than normal and probably only a few degrees shy of where our normal afternoon highs should be. Lows across eastern KS and western MO should be in the low to mid 70s and outlying areas near 70.
Reasoning is that the upper ridge tries to build back in a bit more on Friday and the moisture is a bit lower.
205 PM EDT Thu Sep 21 2017 Aviation A weakening cold front will drop down into the region this morning and dissipate by the afternoon.
Upper level ridge remains the main weather feature, keeping rain chances to our north and west. The warm and humid conditions will remain with us, although 850mb temperatures do indicate that Friday's highs will be a few degrees cooler than today, but still expect highs in the upper 80s to near 90 and lows tonight in the upper 60s to lower 70s.
Mid level high pressure over the Great Lakes and Northeast States will slowly slide east over the weekend, but will continue to contribute to our relatively dry weather and hot weather.
A few storms have popped up along the ridges of northeast Georgia but a weak flow aloft is limiting development/movement off the higher terrain.
In its wake weak isentropic lift combined with the low level jet across west Texas could produce a few isolated showers/storms over the Edwards Plateau and Rio Grande Plains through the night. Friday will see the typical summertime sea breeze showers and storms as high pressure continues to sit over the ArkLaTex region.
Highly amplified upper trough will remain rather stationary on Friday with the axis across the Great Basin. Temps will be around 10-15 degrees cooler on Friday over the CWA, ending fire weather concerns. With increasing large scale ascent ahead of the trough during the aftn/evening, scattered showers and isolated thunder will be possible over mainly southeast Wyoming.
/Tonight through Friday/ Warm front making nice progress across Iowa. Lows tonight will be around what normal highs are for this time of year with readings in the low to mid 70's. we will remain stagnant with a low and front parked out west in South Dakota and Nebraska bringing rainfall to those areas while over Iowa we will be in between the low to the west and the high to the east, while under the influence of an upper ridge.
341 PM EDT Thu Sep 21 2017 High pressure will continue to bring warm temperatures and mostly sunny days through the weekend. A large dome of high pressure along with a very warm air mass.
Another night of very warm lows ranging from the mid 50s in central SD to the lower 70s in northwest IA.
A few showers and thunderstorms are approaching the Tennessee River from the east in association with an elongated trough of low pressure extending from Tropical Storm Jose.
A weak mid to upper level trough builds southwest from Tropical Storm Jose into the northeastern Gulf through Friday, squeezed between a large area of high pressure over the Midwestern U. and the broad area of low pressure around Hurricane Maria east of the Bahamas. At the surface, a weak ridge extends southwest from the Great Lakes into the lower Mississippi River Valley, maintaining a generally light easterly flow across our area.
Surface wise, our region lies on the southern periphery of a continental anticyclone centered over the southeast United States.
210 PM EDT Thu Sep 21 2017 A moist easterly flow will be developing on Friday followed by drier and stronger high pressure this weekend. As of 155 PM: The sfc pattern remains somewhat stagnant, with high pressure extending from eastern Canada down the Appalachian chain, while Tropical Storm Jose remains over the western Atlantic. The high is associated with a sharp upper ridge.
The building ridge and strengthening cap will be the limiting factor for any convection to develop.
High pressure currently located over the Gulf of Mexico will begin to weaken on Friday as a trough of low pressure digs into the southeastern portion of the country.
258 PM CDT Thu Sep 21 2017 Expansive area of high pressure dominates the eastern half of the CONUS this afternoon as southwesterly flow stretches from the southern California coast into the Upper Midwest. The ridge is compressed slightly as it starts to break down. Another deep wave moves across southern Canada, bringing slightly cooler air behind a weak cold front midweek. Central IL then comes under the influence of the deep SWrly flow as the ridge shifts to the east coast and breaks down.
/issued 337 AM EDT Thu Sep 21 2017/ HIGH RISK OF RIP CURRENTS EAST COAST BEACHES THROUGH WET WEATHER POSSIBLE THROUGH EARLY THIS WEEKEND BEFORE DRIER High pressure will remain over the Gulf of Mexico and extend east into the Florida Peninsula today. The high will then weaken over the gulf of Mexico this weekend, as a trough of low pressure moves east through the southeastern United States.
Despite clear skies and southerly winds overnight do expect warmer temps for the lows. to the lower and mid 90s east of the boundary.
The Pacific Northwest remains under an elongated upper level trough that stretches all the way from Hudson Bay to the central California coast. Cold but drier air is streaming into the area in a northeasterly flow from Canada and this will keep temperatures cool again today with upper 50s to mid 60s in the lower elevations and in the upper 40s to mid 50s in the mountains. Temperatures are still warm enough that most of the snow will melt except in the higher mountains. An upper level trough of low pressure will remain over the area with northerly flow producing clouds and a few showers mainly along the higher terrain.
This is associated with the low level jet and warm advection. Tonight the low level jet will crank up once again, with decent focus into the southern Red River Valley and west central MN, not so much further north.
Lingering weak frontal trough that has extended from the Treasure Coast northeast into the Atlantic will break up into tonight.