Aikyam-Lab/Synoptic-Bench huggingface dataset:
High pressure center continued to slide east acrs the MO RVR Valley and squeeze drying northwesterly boundary layer flow down acrs the region, with a lot of low to mid 50 sfc DPTs noted acrs the CWA. Model guidance depicts the evolution of a broad longwave trough across the central CONUS early to mid week.
/issued 237 PM CDT Sat Aug 29 2020/ Upper ridging continues over Texas and New Mexico but the upper ridge is flattened by upper troughs moving over the northern part of the country. A cold front is moving across the Texas panhandle but the cooler air isn't expected to impact this area today.
The rest of today will likely be dry and warmer, as a stout elevated mixed layer spreads east over the region. While a few isolated storms can't be ruled out along the dryline late this afternoon and evening across northwest Kansas, thinking better chances will arrive after midnight across generally northeast into eastern Kansas in the vicinity of the approaching cold front.
Some clouds and left over wind from yesterdays cold front will prevent most locations from cooling to previously forecasted low temperatures this morning. Additionally, cooler air will move over the N.
This will support a strong cold front through the region, supporting gusty NW winds, esp in the lee of the Black Hills where adv level winds are expected. Main sfc cold front will accelerate though the region, pushing the main instability axis east, with the severe threat expected east of the FA today. Much cooler and drier air will advect into the region, with lows in the 40s and some upper 30s. A cold front will cross the area on Sunday, followed by gusty northwest winds. A cold front will cross the area today, bringing strong northwesterly winds and cooler temperatures.
313 AM CDT Sun Aug 30 2020 A fairly strong late summer cold front will swing through this evening. One thing to note with this set up is that the shear, especially the lowest km or two, has strong speed and directional shear which may support some isolated supercells. The stronger winds aloft appear to lag a bit behind the surface cold front with the strong jet energy moving into the eastern Dakotas after 3z.
219 AM EDT Sun Aug 30 2020 High pressure over the Upper Great Lakes this morning will gradually push east and cross our forecast area tonight and early Monday. otherwise axis of high pressure over the Upper Great Lakes will push east across our forecast tonight and early Monday. High pressure shifts off to the east late in the day Monday and Monday night as the next system starts to arrive from the southwest, tracking from the Ohio Valley into Pennsylvania by Monday night.
During peak heating, the high resolution convection allowing models continue to show isolated convection across much of the area except the far west.
A dry cold front near the ID/OR border will move through southwest Idaho overnight, accompanied by gusty winds to 30 mph. Post-frontal cooling will occur with the arrival of the front as the highs on Sunday are only expected to be in the 60s mountains and 70s valleys. Northwest flow will provide our area with mostly clear skies as an upper trough and associated moisture moves through Montana. Cold front near KONO will move through KBOI/KEUL 03Z-04Z and KTWF/KJER 07Z-08Z. Warm conditions ahead of the approaching cold front. In addition, this disturbance will keep cooler conditions across the forecast area, and result in periods of breezy to windy conditions, especially across portions of the Treasure and Magic Valleys.
This should keep heat index values in the hazardous range, potentially reaching as high as the low 110s as we've seen over the past couple of days. Have maintained PoPs in the 30-40% range with the highest numbers remaining in the southeastern portion of the area.
Activity may wane a bit as the low level jet weakens this morning.
/Tonight through Sunday/ High pressure, scattered cloud cover, cooler temperatures, and lower humidity are the main weather stories for today into tomorrow. The cooler, but near-normal, temperatures and lower humidity will persist throughout much of the upcoming week. Precipitation returns to the forecast Sunday night into Monday with an approaching trough from the northwest. The associated cold front will still be arcing over eastern SD into central NE by early Sunday evening, but a narrow band of modest low-level moisture will advect northward in the pre-frontal warm sector providing sufficient means for development of instability beneath steep mid-level lapse rates. Associated storms will likely stay west of Iowa on Sunday evening and by the time the main cold front pushes east through the state, storms will likely be sub-severe, but will provide some much-needed rain to the state on Monday.
324 AM CDT Sun Aug 30 2020 The cold front that brought severe weather to the region has moved well south of the Ozarks. A dense fog advisory has been issued for areas that were showing the lowest visibilities and potential to fall below a half-mile through this morning.
This combined with clear skies should make highs today noticeably warmer than yesterday. Monday a cold front will pass through western Kansas during the mid morning hours and winds behind the front will likely increase to 20-30 mph with gusts to 40 mph. As high pressure moves in during the afternoon we should see the skies quickly clear and sunshine return.
Temperatures on Sunday and Monday will be cooler with abundant cloud cover and precipitation across the area.
The upper ridge is currently centered over western Chihuahua, courtesy of a persistent trough off the CA coast. This southward positioning of the ridge allowed a line of convection to develop into a MCS yesterday afternoon/evening over northern NM, and is currently over north central Texas. Model H85 temps/thicknesses still say today should be a skosh warmer than yesterday, but not by much. Due to the incoming boundary, and increasing high clouds streaming of the west coast trough, we see no need to add to the Heat Advisory already in effect. Models are still in agreement in developing convection along a weak dryline over the higher terrain today and tonight, but this doesn't look to make it into the plains. Monday, H85 temps/thicknesses begin a downward trend and a cold front approaches the area.
354 AM EDT Sun Aug 30 2020 A dry and cooler air mass will take hold today. Rain chances return Monday, mainly southeast of Pittsburgh, as low pressure tracks into the central Appalachians. Dry and comfortable conditions today with high pressure in control. Remnant cooler air plus increasing cloud cover will provide near to below average temperatures Monday.
1100 PM CDT Sat Aug 29 2020 Pretty nice weekend to round out August with cooler and less humid air under the influence of high pressure building in from the northern plains. Surface cold front accompanies the trough, with the NAM/GFS/EC all on good agreement with sliding it across the local area between 12-18z. Looks like a decent shot for rain - better to the north under the influence of the upper level trough - but thunder chances look minimal.
Due to rain, cloud cover and advection of cooler and drier behind the boundary, today has been noticeably cooler than recent days with highs only expected to reach the upper 70s to around 80 degrees this afternoon. Rain and thunderstorm chances will, however, quickly return Sunday night into Monday as our next cold front moves into northeast KS. An active pattern will continue into midweek as a more amplified trough approaches from the northwest.
/issued 237 PM CDT Sat Aug 29 2020/ Upper ridging continues over Texas and New Mexico but the upper ridge is flattened by upper troughs moving over the northern part of the country. A cold front is moving across the Texas panhandle but the cooler air isn't expected to impact this area today. An upper trough broadens and moves over the Northern Plains and Rocky Mountains on Monday and may result in a cold front that brings cooler temperatures to most of the CWA.
1049 PM CDT Sat Aug 29 2020 (This evening through Sunday) Cold front continues to move slowly south/southeast through southern Oklahoma and north Texas this afternoon. Slightly cooler, or less hot conditions, expected as well Sunday.
355 AM EDT Sun Aug 30 2020 Trailing absolute vorticity max within sharp upper level trough was able to pivot across the southern Lake Huron basin between 00-06Z this evening. The differential height increases under substantial confluent flow aloft will support strong Canadian high pressure today and tonight. Rapid expansion of surface ridging down into the meat of Lake Huron is expected to result in loss of persistent nw gradient flow off of the Thumb.
123 AM EDT Sun Aug 30 2020 A dry and cooler air mass will take hold today. Rain chances return Monday, mainly southeast of Pittsburgh, as low pressure tracks into the central Appalachians. Dry and comfortable conditions today and tonight with high pressure in control. Remnant cooler air plus increasing cloud cover will provide near to below average temperatures Monday.
302 AM CDT Sun Aug 30 2020 Upper level ridge to our SW will begin to flatten today putting the area in NW to zonal flow. Nearly zonal flow aloft should be in place Monday morning though this will be short lived as another trough will rotate around a low located in northern Manitoba.
Lows tonight will fall into the lower 60s. Monday a cold front will pass through western Kansas during the mid morning hours and winds behind the front will likely increase to 20-30 mph with gusts to 40 mph. As high pressure moves in during the afternoon we should see the skies quickly clear and sunshine return.
A cold front slides in on Sunday, and brings gusty winds and temperatures near average for the start of the week. A ridge reaching in to the region by midweek brings quiet weather conditions, and high temperatures return to the 90s. Later tonight, a cold front starts to approach our region, and drops into the northern part of the state. During the day Sunday, it slides down the rest of the state, bringing cooler air and breezy conditions. Northwesterly flow on Monday allows more cooler air to pool in, and winds become even gustier.
This afternoon looks fairly quiet with the upper ridge anchored to our west across the Trans Pecos. Afternoon highs may be a touch cooler compared to yesterday so will not issue a heat advisory but nevertheless expect another day of triple digit heat.
High temperatures today should be the coolest (in the mid 70s) along the lake shores due to a persistent onshore wind, and a few degrees warmer (in the upper 70s) farther inland. Temperatures tonight will once again drop off into the 50s outside of Chicago, but temperatures should warm back up into the lower to middle 80s for Monday as the low-level flow shifts back out of the southwest. A cold frontal boundary is expected to approach parts of northwestern IL later in the day and this could act as the focus for some widely scattered shower and storm development.
The high will move east tonight as an upper level disturbance moves into the Ohio Valley. This disturbance will result in a weak wave of low pressure that will bring precipitation back to locations along and south of the Ohio River late tonight into Monday. Highs will range from the mid 70s to the lower 80s. This feature will perturb a wave of low pressure which is forecast to move across Kentucky. After lows in the upper 50s to the lower 60s, highs on Monday will warm into the upper 70s to the lower 80s. Period starts with a wave of low pressure moving east, resulting in a diminishing chance of showers Monday night.
A cold front with gusty winds moves into the Great Basin Sunday and Monday with cooler temperatures. And by cooler, we mean around normal for the date. Then another high pressure ridge builds in for the week and temps climb right back up to hot. An upper low over western Canada is dragging its trough across the interior American West. The associated cold front will cross the Great Basin Sunday and the cooler air and post frontal surface pressure gradient, Monday. Sunday will become breezy and cooler by about five degrees on the highs with lows about normal. Monday more windy, especially in northeast Nevada, and cooler by an additional few degrees. Isolated mostly dry thunderstorms may hap pop up in northeast Nevada Monday as the upper trough axis swings through.
/issued 344 PM CDT Sat Aug 29 2020/ This afternoon's convective coverage should be in waning phase as much of the area has become worked over from convection and outflowboundary flushing the lower moisture convergence. Bermuda ridge extension axis through the central gulf will first suppress nocturnal land breeze near shore and augment gulf breeze onshore flow for possible early onset of showers and thunderstorms along and near the coast Sunday morning. While rain chances will be indicated on the high side, should not be an all day rain, with wettest period in the early afternoon and some canopy debris rainfall lingering through the late afternoon before dissipation.
Tonight and Sunday The short term forecast will remain fairly quiet, as high pressure conditions keep the area dry. Breezy conditions in place this afternoon, with gusts in the 20 to 25 mph range, will come to an end this evening as the atmosphere begins to decouple and the center of the high moves overhead. Sunday, high pressure will be on its way east, but winds will remain light. Temperatures will be similar to today and fairly close to normal, with highs in the lower to middle 70s.
150 AM EDT Sun Aug 30 2020 High pressure will briefly return on Sunday providing warm and slightly drier conditions. Upper trough has shifted to our east. Lows will be in the lower to mid 70s. QPF amounts are forecast around a quarter to half an inch in most locations with the highest amounts north. Expect high temperatures on Sunday to be a couple of degrees warmer than on Monday with more clouds and rainfall around on Monday. High pressure ridge will be in place through the middle of the week with generally diurnally driven convection expected.
1258 AM EDT Sun Aug 30 2020 A dry and cooler air mass will take hold today. Rain chances return Monday, mainly southeast of Pittsburgh, as low pressure tracks into the central Appalachians. Dry and comfortable conditions today and tonight with high pressure in control. Remnant cooler air plus increasing cloud cover will provide near to below average temperatures Monday.
With the cold front well south of the area, so too are any storms previously forecast over southern KS - those are actually across southern OK. This should begin to shift south over the next 24 hours as a more significant Pacific trough translates into the northern Plains. As the system slows into the early morning hours, the cold front appears to stall over portions of the area while the upper flow pattern begins to transition to a southwesterly component. The question at this point is where initial storms form due to uncertainty in the position of the cold front in the afternoon period on Monday.
Should see the highest coverage across the Western Midlands and CSRA this afternoon where moisture and instability will be greatest. High temperatures will reach the low to mid 90s this afternoon with lows tonight in the low to mid 70s. Low to mid level trough expected across the area by afternoon with some enhanced convergence especially across the north Midlands. Air mass moderately unstable and short wave forcing expected as mid level trough moves east from Tennessee.
We will have a break from the showers and storms tomorrow but another cold front will push through again tomorrow night into Monday.
1140 PM CDT Sat Aug 29 2020 Cooler and less humid weather will continue the rest of this weekend over central and southeast IL as weak high pressure settles into IL late tonight and slowly drifts east on Sunday.
Overnight lows will range the mid 60s/low 70s for most locations, upper 50s cannot be ruled out for some of the highest peaks. Garuckas Chattanooga Airport, TN 88 72 85 72 86 / 60 70 80 20 40 Knoxville McGhee Tyson Airport, TN 86 70 83 70 86 / 20 50 80 30 20 Oak Ridge, TN 85 70 82 70 86 / 20 60 80 20 20 Tri Cities Airport, TN 83 66 80 68 84 / 10 50 80 40 20.
Timing tools indicate this lift should become juxtaposed with an approaching cold front across ncntl Nebraska this afternoon setting the stage for isolated to perhaps scattered strong to severe thunderstorms. The short term model blend suggested highs in the lower 90s and the blend of the two data sets produces highs in the mid 90s. In fact, the models are lighting up convection along a stalled cold front across Texas and Oklahoma Monday night.
157 AM MDT Sun Aug 30 2020 A cold front will approach today. Cold front arrives on Monday.
1226 AM CDT Sun Aug 30 2020 High pressure will move through the Northland tonight and depart Sunday. It will be a bit warmer Sunday with highs from the mid to upper sixties close to the lake to the seventies further inland. The cold front and upper trough will continue moving through the Northland on Monday with drying occurring from west to east through the day.
A deep trough will setup over the Rockies resulting in a quick transition to Southwest flow across the Southern Plains and over the Midsouth.
622 AM CDT Sun Aug 30 2020 A fairly strong late summer cold front will swing through this evening. One thing to note with this set up is that the shear, especially the lowest km or two, has strong speed and directional shear which may support some isolated supercells. The stronger winds aloft appear to lag a bit behind the surface cold front with the strong jet energy moving into the eastern Dakotas after 3z.
802 AM EDT Sun Aug 30 2020 Canadian mid level troughiness down to the northeast Gulf of Mexico and north FL along with a subtropical ridge axis near the Florida Keys will maintain a deep moist southwesterly flow today. We had one short wave trough embedded in the mid level trough that swept across the northern part of the state overnight with showers and storms from around Tampa Bay northward. These have pretty much cleared our area but a second short wave trough is expected this afternoon which along with the high moisture and daytime heating will support showers and thunderstorms. The ridge axis lifts north during the last half of the week with winds shifting to southeast and east.
This will support a strong cold front through the region, supporting gusty NW winds, esp in the lee of the Black Hills where adv level winds are expected. Main sfc cold front will accelerate though the region, pushing the main instability axis east, with the severe threat expected east of the FA today. Much cooler and drier air will advect into the region, with lows in the 40s and some upper 30s. A cold front will cross the area on later this morning, followed by gusty northwest winds. A cold front will cross the area today, bringing strong northwesterly winds and cooler temperatures.
Upper ridging extends inland over interior NorCal with closed upper low west of Point Conception.
High pressure in the middle layers of the atmosphere will remain positioned over Deep South Texas and the Rio Grande Valley.
A cold front remains on track to drop into northeast and east-central plains on Monday while afternoon storm chances remain possible across mountain ranges south of Interstate 40.
Trailing absolute vorticity max within sharp upper level trough was able to pivot across the southern Lake Huron basin between 00-06Z this evening. The differential height increases under substantial confluent flow aloft will support strong Canadian high pressure today and tonight. Rapid expansion of surface ridging down into the meat of Lake Huron is expected to result in loss of persistent nw gradient flow off of the Thumb.
This combined with clear skies should make highs today noticeably warmer than yesterday.
747 AM EDT Sun Aug 30 2020 Dry and seasonable weather today will be replaced by increased rain chances Monday, mainly southeast of Pittsburgh, as low pressure tracks into the central Appalachians. Clearing sky and dry conditions will persist overnight as high pressure moves over the region, resulting in seasonable overnight temperature. Remnant cooler air plus increasing cloud cover will provide near to below average temperatures Monday.
Main timing concern impacting elevated these conditions will be the cold frontal passage in the early evening mainly after 6 PM MDT. While the NAM and GFS trend a touch warmer above freezing given the chance for upslope airflow, NBM and ADJMEX have been fairly dominate the last several days to warrant trending to them with WPC guidance to go colder for MinTs.
Otherwise expect cooler temperatures today and especially tonight. Upper ridging is expected to become more established across the western U. with northwest upper flow setting up across the northern High Plains as the current trough shifts further downstream.
This afternoon should not see any storms develop within the area thanks to the atmosphere being stabilized by morning storms and the passage of the cold front yesterday.
This is a result of South Texas being positioned under a general weakness in the mid-levels with ridging to the west and east.
/issued 302 AM CDT Sun Aug 30 2020/ Upper level ridge to our SW will begin to flatten today putting the area in NW to zonal flow. Nearly zonal flow aloft should be in place Monday morning though this will be short lived as another trough will rotate around a low located in northern Manitoba.
346 AM MDT Sun Aug 30 2020 A trough will sweep across the northern Rockies today. The associated cold front at 09Z looks to be from extreme northwest Yellowstone to Billings. Wyoming by 12Z and then begin to stall out briefly along the Bridger/Owl Creek Mts. On Monday, a quick moving trough in the northwest flow will push across the area. Another cool morning is expected behind the front, with freezing temperatures across western valleys and basins.
With precipitation ongoing through the day over much of the region and lingering cloud debris, temps over the Natural State will see some much needed relief from Sat, with highs in the low to mid 80s over Cntrl and Nrn AR, and Srn AR just breaching the 90s.
Latest GOES-16 mid-level water vapor imagery indicates WNW flow aloft ahead of ridging over Texas/northern Mexico. In the longer-term portion of the forecast, modeling consistent in holding influence of the mid-level subtropical ridge across the northern Gulf. Will say that ECMWF was stronger with this ridging vs. the 00Z GFS, though even GFS holds its pretty strong through Tue and Wed, as it's squeezed between a sharp trough in the Southern Plains and an upper low over the NW Gulf.
The high will move east tonight as an upper level disturbance moves into the Ohio Valley. This disturbance will result in a weak wave of low pressure that will bring precipitation back to locations along and south of the Ohio River late tonight into Monday. Highs this afternoon will range from the mid 70s to the lower 80s. This feature will perturb a wave of low pressure which is forecast to move across Kentucky. After lows in the upper 50s to the lower 60s, highs on Monday will warm into the upper 70s to the lower 80s. Period starts with a wave of low pressure moving east, resulting in a diminishing chance of showers Monday night.
333 AM PDT Sun Aug 30 2020 It will continue to be cooler through Monday with marine layer clouds at times along the coast and into some valleys. WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO * Few thunderstorms mountains and deserts Monday afternoon * Cooler start to the week before heat builds mid-late week An upper level trough is the dominant weather feature across the region currently. Temps will continue cooler than we've felt of recent today. Hi-res consensus points to the highest probabilities of thunderstorms along the desert mountain slopes and into parts of the deserts.