Aikyam-Lab/Synoptic-Bench huggingface dataset:
A sfc cold front will accompany the trough, and both are serving to spark a band of showers/storms currently. turning cooler (and even less humid) for Sunday with the passage of the cold front later tonight. Amplified upper level ridge holding over the western CONUS for the start of the new work week, with broad troughing/northwest flow persisting for the local area. Both the GFS and EC suggest bits of energy will top the ridge and drop across the western Great Lakes while at the sfc an area of high pressure slowly meanders east/southeast. Models moving the ridge eastward, breaking it down a bit. Flow becomes more southwest with warmer air returning. A cold front will drop south through the area this afternoon, triggering isolated to scattered showers and storms.
206 PM CDT Sat Jul 31 2021 206 PM CDT Skies are a bit hazy this afternoon as some of the wildfire smoke aloft is advected our way ahead of a cold front. The storms are along and ahead of a cold front that is working southeastward toward our area tonight. Sunday will feature more sunshine, and we will have a reinforcing shot of northeasterly winds and cooler dewpoint air. Highs will top out in the 70s with afternoon wind gusts near 20 mph inland, making for a somewhat seasonally cooler day. This high is expected to promote daily lake breezes and overall cooler than average conditions across the area, especially for the first half of the week.
Behind this activity, there is a cold front that will move into the area tonight. There will finally be a generous push southward tomorrow afternoon, as an upper low drops into the Ohio Valley and northwest flow develops across the region. Elsewhere, high temperatures are only expected to climb into the low to mid 80s as north winds persist. A few strong storms are possible, especially over north Mississippi where the highest instability is.
Relief is on the way though in the form of a cold front currently situated across central Kansas that will continue to slowly sag southward this afternoon and evening into northeastern Oklahoma. Cloud cover and areas of rain will keep temperatures down across most of the area, though the main surge surge of cooler/drier air won't arrive until Sunday night, so it will still feel quite muggy tomorrow afternoon especially where the sun peaks through.
CDG Chattanooga Airport, TN 74 89 68 86 66 / 30 50 20 20 20 Knoxville McGhee Tyson Airport, TN 71 84 66 86 65 / 50 50 10 20 20 Oak Ridge, TN 70 84 65 84 64 / 50 50 10 20 10 Tri Cities Airport, TN 67 82 61 83 62 / 50 50 10 20 20.
45 inches which in close to the highest value ever recorded by the Boise upper air station. In addition, surface observations of dew points in the low 60s in many valley location show the presence of abundant low level moisture.
202 PM CDT Sat Jul 31 2021 A cold front is dropping into our northern forecast area early this afternoon with scattered convection developing along and ahead of it.
Another cold front lays across southern South Dakota into northeast Wyoming into south central Montana this afternoon. Passage of cold front through the region early Sunday will usher closer to near-normal temperatures along with limiting moisture spread mainly to the southern elevated terrain in southeast Wyoming in the afternoon. High pressure builds once more across the American Southwest with continued influence over our region with pockets of vorticity advection leading once more to afternoon showers on the Wyoming side.
308 PM CDT Sat Jul 31 2021 High pressure should keep the area dry for the next several days.
An upper ridge will amplify along the west coast on Sunday, with troughing over much of the eastern CONUS expected to amplify as well.
Overnight temperatures in the upper 70s are likely (some isolated and urban areas may stay near the 80-degree mark) with dew points in the low-to-mid 70s keeping uncomfortable conditions in place overnight. That convection continues after sunset and overnight as the frontal boundary continues to slowly shift southward across the Ark-La-Tex, bringing rain-cooled air and temperatures down into the lower 70s when and where it arrives.
325 PM EDT Sat Jul 31 2021 High pressure will maintain fair skies and dry conditions until the approach of a Sunday cold front. High pressure under wnw flow aloft wl maintain dry and seasonably cool weather tonight. A very strong mid level trough will translate across the eastern Great Lakes and over New York on Sunday with sfc cold frontal passage acrs the Upr OH slated for afternoon/early eve. Given the magnitude of projected deep layer shear (~40Kt) and depth of the mid level thermal trough, severe storms are possible with inhibition coming from an overall lack of instability. The storms and severe threat wl be alleviate via fast trough/frontal progression, and likely clear the area by 8 pm. Large-scale troughing will dominate the eastern CONUS through the week.
Have seen some relief from the smoke across the area this afternoon, as the cold front that pushed through this morning has allowed cleaner air into the area and increased visibilities over 6 miles. Aloft, upper trough axis is quickly dropping southeast across ND this afternoon (main energy approaching the MN arrowhead) and will sweep through the area this evening. This will put the area under northwesterly winds aloft, as we're between the upper ridge over the western Rockies and the upper trough that moves through the Great Lakes and then northeast U.
However, deep convection along a cold front from southern MO east to along the KY/TN state line is thriving on MUCAPES of 4000-5000 J/kg and decent convergence and increasing effective bulk shear values. An upper ridge will amplify along the west coast on Sunday, with troughing over much of the eastern CONUS expected to amplify as well.
Lower dewpoints and cooler temperatures work their way into the area by morning. Tomorrow will be breezy early, but gusts will start to diminish by mid to late afternoon as the high moves into the region. Some areas of smoke may also remain in place across the area, though current projections are for it to eventually push off to the southwest as the high approaches. Cool and comfortable Sunday into Sunday night with low level thermal trough in place.
A cold front in northern Lower is slowly moving south and should push the storms south of the cwa overnight.
642 PM CDT Sat Jul 31 2021 An upper-level trough is currently digging equatorward across the eastern United States. Tomorrow, the front will continue its southward push away from the CWA as high pressure and dry air moving into the Middle Mississippi Valley. This will lead to less clouds area-wide, allowing for temperatures to rise warmer than Saturday, but still remain on the cool side of climatological norms. Ensembles continue to hold the upper-level trough over the eastern United States, keeping the CWA in northwest flow.
A mid/upper trough and sfc cold front are fcst to move through the area on Sunday. SPC MRGL outlook for late in the day over mainly north of I-80 as a cold front sags into PA Sunday afternoon. NW wind kicks in and passage of the upper trough from the Great Lakes will generate plenty of stratus for the N and W. The start of the week will be dry as high pressure builds into the area.
Aside from this, all other terminals reporting VFR conditions, which are expected to prevail through the remainder of this TAF period as high pressure continues to dominate our airspace. Overnight temperatures in the upper 70s are likely (some isolated and urban areas may stay near the 80-degree mark) with dew points in the low-to-mid 70s keeping uncomfortable conditions in place overnight. That convection continues after sunset and overnight as the frontal boundary continues to slowly shift southward across the Ark-La-Tex, bringing rain-cooled air and temperatures down into the lower 70s when and where it arrives.
Still holding onto the heat warning over portions of east central Kansas but will likely be able to expire early as the front continues to sag south with cooler dewpoints filtering in behind. The upper air pattern continues to transition pointing to a cooler next few days ahead. This is helping to aid the push south of the cold front through the area this afternoon as well.
Storms have been sub severe, a report of dime size hail was recently received at white bridge TN.
649 PM CDT Sat Jul 31 2021 Surface outflow boundary moved south to along the highway 54 corridor before weakening at early afternoon and appears the effective cold front will be somewhere along this line at peak heating late this afternoon.
824 PM EDT Sat Jul 31 2021 High pressure will maintain fair skies and dry conditions until the approach of a Sunday cold front. High pressure under wnw flow aloft wl maintain dry and seasonably cool weather tonight. A very strong mid level trough will translate across the eastern Great Lakes and over New York on Sunday with sfc cold frontal passage acrs the Upr OH slated for afternoon/early eve. Given the magnitude of projected deep layer shear (~40Kt) and depth of the mid level thermal trough, severe storms are possible with inhibition coming from an overall lack of instability. The storms and severe threat wl be alleviate via fast trough/frontal progression, and likely clear the area by 8 pm. Large-scale troughing will dominate the eastern CONUS through the week.
605 PM CDT Sat Jul 31 2021 High pressure should keep the area dry for the next several days.
Further north, temps made it into the 70-75 range with afternoon sunshine, so lows will be a few degrees warmer toward Galesburg and Peoria. Northwest of the IL River, where the sun has been out for a few hours, temperatures have recovered into the low 70s as of 3pm, as opposed to mid 60s for areas still beneath the clouds. A secondary cold front, located across southern MN/central WI this afternoon, will bring a reinforcing shot of cool air tomorrow. The combination of north winds behind the cold front, partly cloudy skies, and haze, will result in temperatures only warming to near 80 tomorrow. Cooler, drier weather is expected to continue for much of the work week.
As a front crosses N to S tonight into Sun, SHRA/TSRA will increase with the highest confidence of terminal impacts by 01/09Z at HRO/BPK and between 01/18-20Z elsewhere.
722 PM CDT Sat Jul 31 2021 Overall scenario is that the cold front has cleared the CWA with some elevated showers in the south half of the CWA. These showers should wane toward sunset with lack of heating and the continued exit of the cold front. As the cold front moves farther south, the band of thickest smoke should follow. Noticeably drier air comes in with a second cold front tonight, helping to scour a lot of smoke we have around now.
A few showers and thunderstorms have managed to develop across the area early this afternoon, mainly over the higher terrain.
Primary cold front progd to move southward across Kansas this afternoon and continue to move into northern Oklahoma early this evening. Temperatures on Sunday, for at least the northern two-thirds of Oklahoma and portions of western north Texas, will be 15 to 20 degrees cooler than those seen this afternoon.
However, isolated to scattered showers and storms will impact area sites later tonight and into Sunday as a cold front works through the area. Relief is on the way though in the form of a cold front currently situated across central Kansas that will continue to slowly sag southward this afternoon and evening into northeastern Oklahoma. Cloud cover and areas of rain will keep temperatures down across most of the area, though the main surge surge of cooler/drier air won't arrive until Sunday night, so it will still feel quite muggy tomorrow afternoon especially where the sun peaks through.
Short wave energy expected to reach the northern Great Lakes around midnight then track southeast as it rounds the base of longwave trough toward eastern Great Lakes by Sunday afternoon. Quasi-stationary surface boundary over the southeast US will keep gulf moisture cut off and trailing cold front becomes more diffuse with time as it passes through Sunday. Not much change to the large scale pattern as both ensemble and deterministic models continue to feature troughing over the eastern US and ridging out west.
656 PM CDT Sat Jul 31 2021 A cold front is dropping into our northern forecast area early this afternoon with scattered convection developing along and ahead of it.
/issued 257 PM CDT Sat Jul 31 2021/ SHORT TERM (Tonight through Sunday Night): The large 500 mb ridge that is dominating the western U. As the ridging shifts westward through Sun Night, some weakness may build in the 500 mb flow over the western Gulf of Mex towards the lower TX coastline. Due to the high model confidence will go close to this consensus for the RGV.
Upper level ridging is weakening, with a little cooler onshore flow spreading in.
Today through Monday The ridge axis continues to shift, becoming more N-S orientated this morning, over the western half of the state. The ridge will begin to breakdown over the region Sunday night into Monday.
1202 AM CDT Sun Aug 1 2021 A cold front will drop south through the state through this TAF period. the upper level ridge will drop SW allowing a cold front to begin its progression into the state. A Heat Advisory may need to remain for the far southern counties of the area as the front is not projected to make it to the highway 278 corridor in southern Arkansas before the max heating of the day.
SHORT TERM (Now through Monday): Mid-level ridging over the West and a large scale trough over the East with high pressure over the Gulf of Mexico and a weak cold front pushing into North Texas. A weak cold frontal boundary will push into central and south central Texas today and tomorrow, but kept mentionable pops out of the fcst for now.
335 AM EDT Sun Aug 1 2021 Currently at the surface, the sub-tropical ridge axis continues to extend from the Atlantic across southern Florida. Relatively dry air will keep rain chances limited today with isolated showers and storms developing near the coast in the morning, then scattered showers and storms over the interior in the afternoon, with the highest rain chances expected over the Nature Coast where moisture is more favorable.
Initial thunderstorm outflow has pushed well ahead of the convection, and this boundary should become the effective cold front and sag south into southeast OK/western AR later this morning. Drier and cooler air will finally arrive this evening, as northwesterly upper flow develops.
322 AM CDT Sun Aug 1 2021 Skies were mostly clear across eastern Iowa and northwest Illinois as high pressure was taking hold over the Upper Midwest.
Temperatures will see a downward trend, from above seasonal norms on Sunday (topping out in the low to mid 90s over the majority of the forecast area), to below on Monday (with mid to upper 80s expected) due to increased rain and cloud coverage. The risk for both decrease on Monday, with cooler temperatures bringing decreased instability (MLCapes rising into the 1500-2000J/kg range) along with lower Heat Indices (topping out in the upper 90s).
310 AM CDT Sun Aug 1 2021 Convection has died across the region as the cold front and outflow boundaries that were previously along our southern border have been pushed southward by an advancing low-level anticyclone. Aloft a mid-level trough has dropped southward into the eastern US, throwing the region back into northwest flow. The cold front will also help advance the low-level anticyclone further into the region, clearing clouds out of the area tonight.
This will bring a much anticipated break from the heat, with high temperatures in the lower to middle 80s and lower humidity. For tonight, overnight lows will fall into the lower to middle 60s. Temperatures will remain below normal with highs in the lower to middle 80s and overnight lows in the upper 50s to lower 60s.
Dewpoints in the lower 50s are expected by morning. Winds will be fairly light during this period as well, helping with the cooler lows. Dewpoints are expected to run in the 50s, so the humidity on Monday will continue to be on the lower side. As drier high pressure prevails over the greater region, pops will continue to remain at zero percent during this period.
An upper level ridge over the western CONUS and trough over the eastern CONUS continue to dictate our weather pattern. Initial highs in the mid 80s on Monday will likely begin to creep up toward the low 90s yet again by midweek. The primary shift in the weather pattern is then expected to occur later in the week as an upper trough over the Gulf of Alaska pushes southward toward the Pacific Northwest. This should act to weaken the upper ridge and catapult the Plains into a zonal to southwesterly flow regime. General ensemble guidance and cluster analysis are all in agreement on this solution, with slight variances with respect to timing and magnitude of the weakening ridge.
ABM Chattanooga Airport, TN 89 68 86 66 87 / 50 20 20 10 20 Knoxville McGhee Tyson Airport, TN 84 66 86 64 87 / 40 10 10 10 30 Oak Ridge, TN 84 65 84 63 86 / 40 10 10 10 30 Tri Cities Airport, TN 82 61 83 62 81 / 40 10 10 20 50.
00Z upper air analysis places an upper level ridge axis over the Central/Southern Plains and portions of the Lower Mississippi Valley with the Mid-South being located on the eastern periphery of the upper level ridge axis. Meanwhile, at the surface a cold front stretches from Southern Kansas east through Southern Missouri and into Western Kentucky. Behind this activity, there is a cold front that will move into the area tonight. There will finally be a generous push southward tomorrow afternoon, as an upper low drops into the Ohio Valley and northwest flow develops across the region. Elsewhere, high temperatures are only expected to climb into the low to mid 80s as north winds persist. A few strong storms are possible, especially over north Mississippi where the highest instability is. Expect highs in the low to mid 80s and comfortable humidity.
1138 PM MDT Sat Jul 31 2021 06Z TAF CYCLE A backdoor cold front continues to slide south and west through the region. A backdoor cold front has dropped into northeastern New Mexico, triggering storms that are capable of heavy rainfall, mainly along and east of the central mountain chain. With high pressure aloft reorganizing over SE AZ, storms will move slowly off NM's high terrain at speeds up to 10 mph toward the south and southeast on Sunday.
The day should see mostly to partly sunny skies with diurnal cu development and highs reaching a bit higher than yesterday with afternoon max temps in the low to mid 80s. There is excellent model and ensemble agreement on the large-scale pattern for the upcoming work week, with broad scale troughing dominating most of the eastern U.
326 AM CDT Sun Aug 1 2021 (Issued 326 AM CDT Sun Aug 1 2021) Today through Monday: With the cold front through the area, expect cooler temperatures today compared to yesterday with highs in the low to mid 70s.
357 AM CDT Sun Aug 1 2021 Limited weather concerns are expected in the near-term as upper level ridging builds across the western US. This will help to keep diurnal heating to a minimum and with cooler air filtering in with northwest flow, will keep daytime highs in the 80s for today. Regardless of smoke, temperatures will begin to rise on Monday with afternoon highs ranging from the low 90s in western and southwest Nebraska to the mid 80s in north central Nebraska.
245 AM MDT Sun Aug 1 2021 At the upper levels this morning, upper ridge is situated over the rockies, with the upper trough over the great lakes region, and northwest flow aloft over the forecast area. As the ridge shifts eastward towards the northern plains, temps warm back up for this week, with highs generally in the upper 80s and low to mid 90s all week long.
1128 PM CDT Sat Jul 31 2021 Surface outflow boundary moved south to along the highway 54 corridor before weakening at early afternoon and appears the effective cold front will be somewhere along this line at peak heating late this afternoon.
The region is still being influenced by the broad area of high pressure that has held us in the same pattern for the last few days. There is an upper level trough centered over the Gulf thats helping to fire up this activity however it may be limited to the coastals and immediate coastal Counties / Parishes. Tomorrow the upper level ridge will still influence the area leading to yet again hot conditions, however this will be the last day as the ridge shifts off to our west and a trough continues to move southward.
1235 AM CDT Sun Aug 1 2021 (This evening through Sunday) At this hour, West Central Texas remains under an upper level ridge, providing one last opportunity for relatively benign weather this afternoon. This should help to push a surface cold front into our region by midday.
The concern will again be near ground level smoke and air quality within the weak wind regime of the high pressure with HRRR wind streams suggesting the most dense smoke plumes will move into NW MN and spread to the south before shifting west over the valley this afternoon. Upper pattern will feature troughs out over Pacific and close to the Eastern seaboard, as ridging continues to hold over the Rockies and High Plains. Some guidance indicates that troughiness entering the Pac NW midweek will act to flatten the ridge and allow for precipitation chances over our forecast area by the mid to late week period.
1138 PM EDT Sat Jul 31 2021 Weak high pressure builds across the ares overnight and then passes to the east in the morning. Low pressure developing along the Mid Atlantic coast in the afternoon will track just south and east of the area Sunday night. High pressure builds into the region Monday and settles over the area Monday night, then remains into midweek. Meanwhile, a nearly stationary frontal boundary south and east of the area will have waves of low pressure moving along the front.
The Evening Update: Cloud cover from the Desert SW has been shifting Ewd this evening as the Ern Pac trof moves inside 130W. Weakening of the ridge has allowed virtually the entire CWA to enjoy some cooling. Save for KSMF at 05z, the other sites were running from 1 to 11 degrees cooler, albeit the Delta Breeze is weaker and the marine layer just slightly deeper. Forecasts suggest energy within the Ern Pac trof W of 130W will be dropping Swd on Sun which should slow the Ewd progression of the trof allowing for warmer temps away from the Delta influence. JHM Upper level ridging is weakening, with a little cooler onshore flow spreading in.
But with how poorly the high resolution Convective Allowing Models (CAMs) have performed over the past few days it's worth keeping an eye on the southern TN valley this afternoon.
Under the persistent high pressure pattern, light winds and sunny skies are expected today. Through the first half of the week the western CONUS ridge remains in place, though with gradual height reductions.
This high pressure should back into wrn and ncntl Nebraska presenting cooler temperatures and a continued decrease in humidity. The temperature forecast leans on the cooler short term model blend plus bias correction. This forecast factors in the effects of smoke aloft which could keep high temperatures a few degrees cooler than the very warm MET and MAV guidance which suggest highs closer to 90. The official forecast is close to the cooler ECM guidance. The models are in good agreement showing an upper level ridge of high pressure across the Rockies this afternoon.
With the persistent high pressure aloft beginning to weaken today and an approaching upper-level weakness and a late season "cold" front from the north sagging further south and into TX, this convective activity will be more widespread today and push further north than we have seen over the last few days. For tomorrow, with the help of rainfall and increased cloud cover, heat index values will drop slightly to the low-to-mid 100s.
Fog has developed across central Illinois early this morning, with 07z/2am obs showing the lowest visbys concentrated along/southwest of a Quincy to Taylorville line. After the fog dissipates, SCT-BKN diurnal clouds will develop along and ahead of a cold front dropping southward through the region.