Aikyam-Lab/Synoptic-Bench huggingface dataset:
850 mb temps cooling enough with this second wave so that light snow is the predominate type, though some rain mix is psbl just due to enough warming in the lowest layers nr the sfc where temps are in the mid 30s. And believe this may be freezing rain to start with before changing to snow. The first round of colder air will move in as a cold front moves through.
1155 AM EST Mon Dec 18 2017 A frontal boundary will remain north of the region today as high pressure remains centered over the southeast US.
There is some shallow moisture trapped in the high country, so expect a bit more cloud cover there, while most of the cirrus should stay thinner over the plains barring significant mountain wave enhancement. Peak gusts may be able to reach 40-50 mph in some of the wind prone areas of the higher foothills this morning, but then gradually relax as shear profile becomes less favorable for significant mountain wave deflection today.
In addition to the low stratus, fog is expected to begin developing around 00Z at all TAF sites. /issued 530 AM CST Mon Dec 18 2017/ The subtropical jet continues to stream moisture in from the eastern Pacific as the warm front has push inland over the region.
The ridge is maintaining stable conditions over the area with temperatures in the upper 70s to lower 80s and dew points in the lower to mid 70s.
1018 AM CST Mon Dec 18 2017 Area of precipitation, mainly freezing rain, over far NW MN and moving ESE. And believe this may be freezing rain to start with before changing to snow. The first round of colder air will move in as a cold front moves through.
South of this boundary is an unseasonably warm and moist airmass with dew points in the mid 60s north to lower 70s elsewhere with temps as warm as the lower 80s near the coast. Low temperatures will be in the lower 60s.
233 PM CST Mon Dec 18 2017 An east to west oriented jet max will move through North Dakota tonight which will allow a cooler high pressure to drop south. Just a touch of a surface pressure gradient ahead of this high pressure should allow for mild Tuesday morning low temperatures, roughly mid to upper 20s in most locations. Even with the cooler air in place on Tuesday, high temperatures will be a good 10 to 15 degrees above normal.
As the upper level low becomes more of a wave and moves east-northeast into central Oklahoma, the western extent of the rainfall might get into parts of the far eastern TX Panhandle, in particular south of I-40.
350 PM EST Mon Dec 18 2017 A frontal boundary will continue to lift north of the region tonight with high pressure building into the region through Tuesday.
A cold front will move across the Panhandles late in the TAF cycle. /Issued 410 AM CST Mon Dec 18 2017/ A closed low currently resides over northwestern Mexico/southwestern AZ.
This will be the last day of high pressure before the change in pattern occurs with rain and snow coming into the Pacific Northwest. /Issued 405 AM PST Mon Dec 18 2017/ Fog and freezing fog has developed over the usual places this morning in the Umpqua valley and near the Illinois valley in Grants Pass.
Will need to watch thick mid-high clouds moving over the area, as temps may end up being a touch cooler than initially thought. On warmer southwest to west flow, 850mb temps will rise to 3C to 6C. Expect the cold front to sink across across our northern counties by 03Z, and exit to our south shortly after 06Z Tuesday. While a the 00Z and 06Z run of the GFS do indicate some light snow possible over the northwestern counties 00-06Z Tuesday, the main change will be increased cloud cover, a northwesterly turn to the winds, and cooler air.
Mid/high clouds are in place east of an upper low INVOF sw NM. For now we will omit including -SHRA in the TAFs, but they will probably be around between 09Z-18Z Tue depending on how fast upper low moves through.
337 PM EST Mon Dec 18 2017 A ridge will remain over the Upper Ohio Valley and Lower Great Lakes tonight, but a cold front will push across the forecast area late Tuesday. Dirty ridge remains over the Upper Ohio valley and Lower Great Lakes. A cold front move across the area late tomorrow ushering in more seasonal conditions.
Based on latest hi-res guidance, the higher rain chances were shifted back to the west into our far southwest zones in Deep East Texas. A warm front near the coast with dewpoints in the lower 70s over the gulf waters will begin pulling rich moisture onshore with pcpn water values nearing 2 inches, very unseasonally high. This slow movg warm front will reach near the interstate 20 corridor by Tue aftn with very heavy rain near this frontal boundary.
Florida remains in a rather weak pressure pattern aloft this afternoon with a ridge just east of the state and troughing well to our north. For tonight into Tuesday, the flow aloft becomes more southwest as the trough begins to deepen across the central/eastern part of the country. This will push a surface frontal boundary into the southeast through the day on Tuesday, with high pressure remaining to our northeast. The period will begin a mid/upper level trough moving across the eastern U. with its associated cold front moving into the southeast states.
Environment transitioning to SW moisture return off the Gulf ahead of an amplifying longwave trough and associated translated sfc cold front set to begin influencing the northern CWA by tomorrow afternoon.
313 PM EDT Mon Sep 4 2017 A strong cold front will approach the Ohio Valley late tonight bringing a broken line of showers/storms to southern IN/central KY late tonight through Tues morning. The cold front and storms should push through Tues morning with lingering post-frontal showers slowly moving out Tues afternoon. Tuesday highs should fall back into the lower 70s. Mainly dry conditions are expected Tue night with lows dropping into the lower 50s with a few upper 40s readings expected.
Low temperatures tonight should be a little warmer with lows in the middle 60s to lower 70s. Southerly flow and increasing dewpoints will be the cause for the slightly warmer night time lows. Highs should also be a degree or two warmer given the warmer start and persistent conditions. A deep trough moving through the Ohio Valley will send our first decent cold front of the season southward into our area beginning late Tuesday night.
A strong cold front located from the lower Great Lakes to southeast Kansas will drop quickly south overnight and be located from Paris to Jonesboro by 12z Tuesday. North Mississippi stands the best chance for seeing a few strong storms as the airmass destabilizes ahead of the front with SBCAPES greater 2000 j/kg and some marginal shear spreading south with broad upper trough.
A cold front will approach the area Tuesday, and slowly work its way through the Mid-Atlantic by the end of the week.
/Issued 716 AM EDT Mon Sep 4 2017/ Local area continues to be under the influence of high pressure from the mid atlantic states through North GA providing for a tranquil weather pattern. In general went on the high side of guidance, especially for NW corner late where PWs increase to 1.
242 PM CDT Mon Sep 4 2017 OVERVIEW: Primary change to the inherited forecast was to insert some smoke across our northern zones tomorrow morning following a cold front. Otherwise, the trend towards a highly amplified pattern remains intact with longwave ridging holding to our west and deep troughing over the eastern CONUS.
Fortunately, a cold front is blasting south across the region and was analyzed from near Rawlins, WY, to near Denver, CO. It will be cool, given H7 temps in the lower single digits C along/E of the Laramie Range, but winds should be on the light side with weak gradients. Dry weather persists through Wed as upper-level ridging slowly builds into the area.
Surface cold front pushed south through western Kansas today, and by 20z, this front had pushed all the way into the Oklahoma Panhandle. 850mb temperatures falling to 11-13C range will support much cooler temperatures with highs generally lower 70s after some sun finally peaks out around midday to early afternoon.
549 PM EDT Mon Sep 4 2017 After a warm Labor Day, A cold front will bring thunderstorms and rain overnight, and will usher in below average temperature for the remainder of the week. As the aforementioned upper trough amplifies over the Midwest/Great Lakes on Tuesday, eastward frontal penetration power will be compromised by southwest/semi-parallel flow aloft.
This represents the digging upper trough into WI. The main upper trough axis will then approach from the north for Tue afternoon.
While the airmass is much cooler than yesterday, it will also be significantly drier. With temps in the low to mid 70s, RH values should fall below 30 percent. Cooler temperatures are expected on Tuesday with highs only in the mid 60s to the mid 70s. With the center of a high pressure over the western CWA Tuesday night, winds will become light and variable.
Thanks to a rather robust upper trough, it will feel more like Fall as temperatures stay well below normal Tuesday night through the weekend. Overnight low temperatures will bottom out in the upper 40s for some along the Cumberland Plateau and in the low 50s for those of us in lower elevations.
An upper trough dropping south from the Great Lakes into the Midwest will cause a break period of weak frontogenesis after midnight across southwest Nebraska. On Tuesday, clear skies and cooler 850mb temperatures of 10 to 14C support highs in the low to mid 70s.
The cold front will continue to march quickly south and east overnight into Tuesday morning, and will be south of the Red River by early afternoon. Model guidance (hi-res ARW/NMM, HRRRX, NAM, GFS, ECMWF) has trended much drier today over our area in the post-frontal regime, with the only decent signal being a band of showers along the low-mid frontal zone near the KS border Tuesday morning.
A large upper level trough will swing across the northern Plains/Great Lakes region tonight into Tuesday. This will send a cold front into the Big Country late Tuesday morning, then through the rest of the area by Tuesday evening. Highs will mainly be in the low to mid 90s. (Tuesday night through Monday) As a cold front continues to push through the region Tuesday night, the chance for showers and thunderstorms will persist.
300 PM CDT Mon Sep 4 2017 WV imagery shows the upper ridge anchored over NV, covering most of the wrn CONUS, and nosing down into Texas. To the north, a cold front is moving thru the Central Plains, and set to arrive in West Texas and Southeast New Mexico Tuesday. Models are in pretty good agreement in bringing the aforementioned cold front into the Wrn Low Rolling Plains after 18Z Tue. Models are stingy on developing QPF along the pre-frontal trough during the afternoon, yielding isolated chances at best.
The first slight chance for precipitation will come this evening as a cold front is moving through the area. Cooler air is already advecting into the area behind the front as temperatures across northern Missouri are in the upper 70s and out ahead of the front temperatures are in the upper 80s and lower 90s. This cold air advection will continue tonight into tomorrow with considerably cooler highs on Tuesday in the mid 70s.
A large upper longwave trough begins to dig south over the north-central CONUS and Midwest through the near term, pushing a strong surface cold front south into the Tennessee River Valley by Tuesday evening.
Forecast issues will be temperatures through the period along with the low chance of precipitation tonight. Broad and strong ridge is dominating most of the western half of the country with a trough over the eastern portion leaving a northwest flow aloft over the area. Cold front and easterly upslope winds look to be through the entire area by late morning. So did not make any changes to the high temperatures. Based on that and good collaboration I lowered the lows from what the blend gave me.
A mid/upper level low centered over northern Mexico just south of Big Bend is progged to get pushed south tonight through Tue as high pressure moves into the area from the NW. However, the weak baggy upper trough over E TX will move little tonight and Tuesday, then shift east Tue night. This pattern will lead to a more northeasterly flow aloft across S TX which will help push a cold front into N Central TX Tue. The higher pops then shift inland across the southern half of S TX during the day Tue. Models prog rain chcs to lower to a slight chc across S TX Tue night as PWAT's briefly decrease well ahead of the cold front.
A similar, albeit cooler day is in store for Tuesday with 850 mb temps in the 2 to 5C range.
06Z surface data has the cold front running from northern Wisconsin, to near KFSD, and then into southwest Nebraska. Dew points were in the 50s across the Great Lakes with 60 dew points from just ahead of the front into the lower Mississippi Valley. The cold front should enter the far northwest parts of the area around mid-morning and exit the far east and southeast areas by late afternoon. Well advertised much below normal temperatures still on track for a good portion of the week, as an upper level trough sharpens over the eastern U. while a large upper level ridge of high pressure builds over the western CONUS.
This, combined with east winds from the overnight passage of a strong cold front has resulted in very poor air quality across much of the Northern Rockies. Sadly little improvement is expected over the next 24 hours as additional smoke production today along with the existing smoke are likely to become trapped by increasing stability as high pressure builds over the area.
There was little backing of winds at low levels, but decent deep layer shear and some turning and considerable speed increases in the lowest 1-3 km would support organized convection and the continued threat of severe storms, mainly from wind and hail. - Lenning 129 PM CDT The upper air pattern will remain meridional with an expansive ridge across the west.
/issued 927 AM EDT Mon Sep 4 2017/ A fairly weak pattern is in place aloft this morning with ridging to the east and troughing well to our north, setting up a westerly flow in the mid and upper levels. At the surface, the ridge axis is centered north of the forecast area, with a weak low-level southeasterly flow across the region. High pressure to our north with a relatively weak pressure gradient in place over the region will keep light winds and seas in place through mid-week.
A cold front will move across the TAF sites Tuesday morning which will swing the wind to the northeast and could be gusty at times through the afternoon. Although wind speeds will remain fairly modest (5-15 mph), there will be enough downslope component on top of the minor thickness increase to see highs today about 3-5 degrees warmer than yesterday. A cold front is still progged to move through the forecast area early Tuesday ushering in cooler temperatures.
302 PM CDT Mon Sep 4 2017 Another fairly warm day across the Panhandles with much cooler weather on the horizon. A pre-frontal trough is already on our northern border which has switched winds out of the north across southwestern Kansas. We've also seen a denser cloud of smoke moving south behind the trough. As the cold front pushes south of the area Tuesday daytime will bring much cooler temperatures to the area.
328 PM EDT Mon Sep 4 2017 A cold front will approach from the northwest tonight and will gradually stall over the area on Tuesday.
Much cooler temperatures the next several days is the main highlight of the forecast through mid week. Current northwest flow from western Canada into the Mid Atlantic will buckle, with a deep longwave trough extending from Hudson Bay into the southeastern U.
Lighter winds and cooler than average temperatures are then expected tonight into Tuesday as northwest flow prevails on the backside of a deepening upper trough over the Great Lakes and a prevailing ridge over the western U. Fairly quiet period expected with the upper ridge in control over the area through most of the period.
334 PM CDT Mon Sep 4 2017 Wx map shows weak high pressure over the SE US through TX, giving light and variable winds. Across the upper levels, a significant trough will deepen across the Central and East U.
Canadian cold front has dropped through the region, bringing cooler temps. Rh values are slightly higher than previous days due to cooler temps.
216 PM EDT Mon Sep 4 2017 A cold front and associated showers and some gusty thunderstorms will move across the northwest third of the state tonight, then progress east across the state during the day Tuesday, focusing the severe weather threat across the southeast half of the state on Tuesday.
The air mass still appears capped over the lower deserts, per the SPC mesoanalysis page, but further heating should erode most CIN by late afternoon. Similar to earlier analysis, the environment remains conditionally favorable for strong multicellular convection to move off the higher terrain over the lower deserts, amidst 15-20 kt of easterly midlevel flow. Still some uncertainty about if/how widespread thunderstorms will be across the lower deserts, with the relatively higher chances across northern/eastern portions of the Phoenix area, but strong to marginally severe wind gusts and blowing dust will be possible with any thunderstorm.
/issued 331 AM CDT Mon Sep 4 2017/ Slightly faster arrival and exit of the Cold front and associated rainfall is the only significant change in the forecast this morning. One more warm day today before we see a much cooler temperatures arrive across the Midsouth.
A cold front currently entering the Texas Panhandle will move south over the next 24 hours and enter our northern CWA around midnight tomorrow night.
A weak cold front will ease into the region Tuesday. /issued 300 PM CDT Mon Sep 4 2017/ WV imagery shows the upper ridge anchored over NV, covering most of the wrn CONUS, and nosing down into Texas. To the north, a cold front is moving thru the Central Plains, and set to arrive in West Texas and Southeast New Mexico Tuesday. Models are in pretty good agreement in bringing the aforementioned cold front into the Wrn Low Rolling Plains after 18Z Tue. Models are stingy on developing QPF along the pre-frontal trough during the afternoon, yielding isolated chances at best.
A cold front will bring a surface wind shift to Oklahoma and north Texas 23 UTC Monday through 13 UTC Tuesday. /issued 338 AM CDT Mon Sep 4 2017/ Veered flow ahead of cold front will yield quite the warm up this afternoon. High temperatures across northwest parts of Oklahoma yesterday reached the upper 90s, so temperatures slightly above 100 appear reasonable over a large portion of northern and western Oklahoma as lower level thermal ridge spreads east. Influence of upper level ridge near frontal boundary as strongest flow and height falls stay well north of the boundary, along with veered flow and meager moisture, PoPs were reduced most areas for late Monday night through Tuesday.
333 PM CDT Mon Sep 4 2017 Much cooler temperatures are heading our direction as a longwave trough deepens from the Hudson Bay into the Mississippi River valley region. This leaves our region under strong north/northwesterly flow as a strong ridge of high pressure over the western states continues to build north into Canada. Brisk northerly winds are also expected the next couple of days, as high pressure pushes out of the Dakotas.
Northerly flow and below normal temperatures are anticipated to start the extended periods as an amplified area of high pressure stretches into the Pacific Northwest. This ridge is anticipated to give way to an upper level disturbance late in the week.
Regardless of rain, today marked a big change in the weather as temperatures were 10 to 20 degrees cooler compared to yesterday.
1233 PM CDT Mon Sep 4 2017 Cold front extended from southeast Iowa into northwest Missouri late this morning. Do not expect much activity along the fnt, other than cooler temps and some clouds, until late this afternoon. While storm motion shud be ESE, development shud spread swwd with the approach of the upper trof and low level cooling. Prev mdl solns suggested a frontogenetical band of precip behind the fnt as the main trof digs into the area.
We'll see a highly amplified synoptic pattern around the middle of this week with strong ridging in the Western US and a deepening trough across the Eastern US. On Tuesday, the trough digs southward into the Southeastern US and pushes a significant cold front into Central AL. Any convection should be elevated with the anafrontal boundary, and while elevated instability will help in the development of some thunderstorms, I don't expect to see a solid line of thunderstorms that is typical with cold fronts in this region.
A band of altostratus has settled across N-central MT associated with a continuing push of a cooler and more humid airmass. Forecast soundings continue to suggest the cooler air could mix out with gusty north winds and afternoon relative humidity dropping near 20 percent east of a line from Havre to Lewistown.
A moist tropical pattern persists over South Florida on this Labor Day, with temperatures reaching into the lower 90s over most of the area and heat index values rising into the 100s.
Expect a slow increase in shower and thunderstorms activity for the remainder of the week, as high pressure weakens and southerly flow develops. The remainder of the week will see a shift in the pattern with the ridge over the Great Basin weakening and shifting to the east. We will also see the development of low pressure off the southern California coast.
/issued 322 AM EDT Mon Sep 4 2017/ A strong ridge of high pressure to the northeast should keep the easterly flow across the region for the next couple of days. With the higher PWATs there could be some urban street flooding, especially along the Gulf coast. Otherwise, should be garden variety type thunderstorms, although if the 500mb temps are a little cooler than models indicate, there could be some stronger storms as well.
Cold pool with southward digging 500 mb trough combined with just enough heating to create steep lapse rates in the lowest levels with 500-1000 j/kg.
331 PM CDT Mon Sep 4 2017 Cold front currently extends from northern Illinois into west central Missouri. Would expect thunderstorms to develop in the next 1-2 hours as mid level ascent increases slightly on the tail end of a mid level trough that will move through the Great Lakes.
314 PM CDT Mon Sep 4 2017 Another fairly warm day across the Panhandles with much cooler weather on the horizon. A pre-frontal trough is already on our northern border which has switched winds out of the north across southwestern Kansas. We've also seen a denser cloud of smoke moving south behind the trough. As the cold front pushes south of the area Tuesday daytime will bring much cooler temperatures to the area.
Cold front working into northwest IA at 08z, and have seen a small- scale blossom of lower clouds immediately around the advancing front from near KMWM and KOTG toward KSHL where lower level moisture has pooled. The story for the day will be the transition to cooler, breezy and drier conditions. Despite drying of the lower levels, the sharp cooling in the mid-levels steepens up lapse rates a touch and allows enough surface-based instability to start thinking a few showers around southwest MN by early to mid afternoon. In the intermediate term, the upper pattern is meridional with a large trough of low pressure carved out over eastern North America, and upper ridging throughout the intermountain west.