Aikyam-Lab/Synoptic-Bench huggingface dataset:
1247 AM EDT Fri Aug 20 2021 Persistent high pressure holding over the Western Great Lakes region provided Northern Michigan with another perfect late summer day and evening. High pressure remains centered over the southern lakes and northern OH Valley. With a humid airmass in place (dew points in the low-mid 60s), fog is again expected. High impact weather potential: Minimal Synopsis/Pattern: Upper level troughing across the lower Great Lakes Friday morning will close off into a cutoff low and sink southeast toward the mid-Atlantic through the day. Details/Forecast: We continue the quiet weather for Friday with dry low levels and surface ridging.
The chance of convection will continue into Saturday as weak mid level support will persist over the area east of a H5 s/wv ridge. A broad 500 mb ridge will encompass much of the southern two-thirds of the nation.
Friday night, rain chances remain limited statewide as high pressure aloft at 500mb moves into the region. Saturday, a 500mb ridge becomes the main player and northwesterly flow with moderate forcing in the northeastern and central expanse of the CWA could promote convection across northeastern Arkansas and central Arkansas later into the afternoon/evening timeframe. Saturday night, rain chances remain limited to northwesterly flow around the periphery of the high in the northeastern portion of the state.
421 AM EDT Fri Aug 20 2021 High pressure will lead to areas of dense fog this morning. The threat for showers and thunderstorms is forecast to be isolated today under this weak high pressure.
Subtropical Ridging settles in over our area today into Saturday. Deeper moisture on the far northern edge of Tropical Cyclone Grace briefly moves into areas along and east of the I-35 corridor to southern parts of the Rio Grande Plains.
1209 AM CDT Fri Aug 20 2021 (This evening through Friday) Showers and thunderstorms have developed to the west of the area over the higher terrain of the west Texas mountains. Lows tonight will be warm and muggy, likely only falling into the low to mid 70s with the higher than normal amount of moisture in the area.
By Saturday morning, a weak cut-off upper level low will be spinning near the Mid-Atlantic while an upper level ridge tries to nose into the Tennessee and Ohio Valleys. A weak cold front will be moving into the Midwest during this timeframe.
Deep layer ridging remains centered along the northern Gulf Coast, generally oriented west to east. A piece of the ridge extends northward through the Mississippi River Valley. Troughing exists on either side of this ridge axis, and the weather today and tomorrow will be driven by the trough over the eastern Great Lakes and Mid Atlantic region. The upper level trough extends southward along the Appalachians, keeping Central Alabama under a northwesterly flow pattern. A series of impulses will rotate through the western side of the trough and combine with an airmass characterized by PW values of 2.
Largely dry conditions are expected today and Saturday despite and upper low over the area as warm air aloft from h850 to h700 keeps convection capped. Long range deterministic models indicate that a large scale ridge should be prominent for the beginning of the week, reinforcing warm temperature. VFR will then prevail tomorrow after morning fog burns off soon after sunrise with few clouds and a light north wind due to Great Lakes high pressure. Periodic restrictions with mainly aftn convection is expected through the weekend under broad upper troughing.
The mid level ridge axis that was overhead today and likely contributed to the overall diminished shower activity is forecast to shift east overnight as the upper low over the Intermountain West begins to move across the central Rockies. Updated the forecast overnight to reorient POPs some with the highest chances across the eastern third of the area. Overall activity is expected to remain fairly isolated though a few clusters could develop where some locally heavy rainfall occurs within an anomalously moist airmass with a deep warm layer, especially within the highest PWATs from southeast OK into west-central AR.
The area of continued development will spread eastward through the afternoon and evening as the pattern shifts east and a short wave trough ahead of the main upper trough lifts out across the central High Plains region. A cold front moves through the area after midnight tonight with a few showers possibly lingering across the area into early Friday as the main upper trough moves across the central High Plain by mid-day Friday. Dry conditions will be in place late Friday through the day on Saturday with subsidence aloft, dryer air, and cooler temperatures on Saturday. Another short wave trough in the southwest flow aloft moves across the area Saturday evening for a slight chance of thunderstorms.
Temperatures will then trend back upward and reach warmer than average by midweek. Hazy skies due to smoke will continue until at least this evening before the flow aloft turns more westerly ahead of the next approaching trough of low pressure passing over Northern California and the Pacific Northwest.
The overnight period is expected to be rather warm and muggy, with overnight lows generally in the low-70s. This may allow afternoon highs to climb into the low-90s across the far western CWA. CAM members are in general agreement in placing a cold front along the I-35 corridor across central Kansas/northern Oklahoma by 00z Saturday. The cold front may ultimately slow or even stall out across portions of central Missouri during the day on Saturday.
High pressure stretching across the area will keep northerly winds in place today. Afternoon highs will be in the low to mid 90s with heat indices flirting near advisory levels through the weekend. Then, ridging builds back in and winds become more easterly. High pressure will continue to dominate across the Gulf waters keeping typical summertime conditions. Increasing moisture and light winds will prevail across fire districts, as high pressure dominates through the period.
Largely dry conditions are expected today and Saturday despite and upper low over the area as warm air aloft from h850 to h700 keeps convection capped. Long range deterministic models indicate that a large scale ridge should be prominent for the beginning of the week, reinforcing warm temperature. Periodic restrictions with mainly aftn convection is expected through the weekend under broad upper troughing.
An upper level trough will move over the southern Appalachians in the near term. Rain soaked areas may develop fog late tonight due to the higher moisture near the surface. Lows tonight will be in the low to mid 70s again. A weak upper level low pressure system develops over the Central Appalachian Mountains Friday through this weekend. Temperatures will be above normal with highs in the lower to mid 90s and lows in the lower to mid 70s. High pressure aloft builds over the Central U. Upper level trough will continue to dig southeastward into the forecast area today. There will be the chance for afternoon and evening convection again associated with the upper trough moving through the region but confidence in impacts at terminals remains limited.
Large upper level low/trough centered over the eastern Great Lakes. Good height fall center/700-500 MB low to track across northwest Ontario on Saturday, with 500 MB ridge holding over southeast Michigan through the day, maintaining dry conditions. The cold front over the Western Great Lakes will more or less wash out as it pushes into the Central Great lakes.
High pressure remains in control with warm and humid conditions over the Upper Mississippi Valley. The cold front will arrive in the western counties after midnight Friday night, and exit the eastern CWA late Saturday morning.
No major changes to the short term forecast, expecting overnight temps to bottom out in the low to mid 70s, with some areas across N GA making it down into the mid to upper 60s. On Friday, the forecast area will be situated in a northwest flow regime aloft between the building ridge to the west and trough over the Northeast. While the impetus for development will be less clear cut than today, the combination of the moist airmass as well as any weak perturbations working around the periphery of the trough will allow for the development of scattered thunderstorms again by Friday afternoon. 5-2") lingers across the area until the fringes of the high begins to push it off towards the Gulf, so a diurnally- forced convective pattern will be maintained through the weekend.
The persistent ridge across the southern CONUS remains anchored over the Lower Mississippi Valley, its western periphery edging into West Texas. Southwest flow aloft continues over the region as subtropical moisture is routed between the western edge of the aforementioned ridge and the southeastern periphery of an approaching trough, currently progressing eastward through the Rockies. High temperatures this afternoon will be similar to yesterday, in the lower to middle 90s across the plains, 80s in the mountains, and lower 100s through portions of the Rio Grande Valley. Saturday will see the start of a pattern shift as the ridge continues building westward and the trough progresses from the Rockies northeastward toward the Upper Midwest. Locally, a drying trend is expected as subsidence beneath the building ridge increases, with thunderstorm chances Saturday afternoon focused mainly across the higher terrain and adjacent plains.
327 AM EDT Fri Aug 20 2021 Latest analysis shows an upper level trough just to our east which is expected to become a closed low later today and meander over the Mid Atlantic through Saturday. To our west, upper level ridging extends from the mid west up through the upper Great Lakes. Afternoon high temps in the low to mid 80s. The large scale pattern across the CONUS in the extended will feature a large upper trough coming onshore in the Pacific Northwest to begin the period, with a ridge of high pressure sprawled across the the Great Plains, Great Lakes, and the Ohio and Tennessee Valleys. A ridge of high pressure will be in place over New England, while tropical cyclone Henri should be somewhere off the Mid- Atlantic coast.
220 AM MDT Fri Aug 20 2021 The H5 trough is currently centered roughly over Thermopolis this morning, slowly drifting eastward. The trough will continue ejecting NE through the next 12 hours, Slowly drying the atmosphere in its wake. With the trough departing, the wraparound activity will be more showery in nature, with smaller areas getting any measurable precipitation. This will be brief, as the next trough drops southward into the Pacific Northwest.
1135 PM EDT Thu Aug 19 2021 A cut off upper low will drift southeast across the region for the next few days with unsettled and occasionally showery conditions lasting through the upcoming weekend. Lows by daybreak should range from around 60 in the northern mountains, to near 70 in parts of the Lower Susquehanna Valley.
Minimal support aloft today given the mid-level ridge and convergent portion of the upper jet atop a weakly sheared environment (EBS of 15 knots or less) hinder narrow showers/storms of the pulse variety. Eastern upper low will gyrate and retrograde Friday as the PV anomaly releases through the Ohio Valley, arcing toward the Mid- Atlantic. Forecast soundings depict a subsidence inversion near H7 given ambient isentropic downglide associated with regional anticyclone. Saturday will be warmer as heights rise ever so slightly.
Snow levels were down around 11kft in some of the guidance over some parts of the San Juans, so there does stand a chance for some snow accumulation over the highest peaks tonight. Main upper trough is expected to pass through early on Friday, with the area on the back side of this system by midday and early afternoon. Slightly cooler air mass expected to be in place on Friday, with temps falling back towards more normal conditions. Cooler temps and mainly dry weather expected going into the weekend.
259 AM EDT Fri Aug 20 2021 Low pressure slowly pulls away to the east today while a warm and humid air mass remains in place across the area. Low pressure slowly moves east today with moisture lingering in its wake. Although the low lingers near the Midcoast or downeast Maine, model forecasts seem to favor southern NH and southwest Maine with the lingering cloud cover and if that's the case then the warmest areas will actually be near the Canadian border where mid 80s are possible. Cold front associated with the leading edge of high pressure moving southeast into the Canadian Maritimes gets hung up or washed out over the far northern parts of our area tonight into Saturday, so the cooler air doesn't really arrive.
The area will remain under the influence of an upper low/trough at least into early Sun. To start the workweek, upper high will be fairly strong over the area but by mid-week, it will retrograde a bit.
High pressure across the region with a dry airmass across South Florida. Not much changes as we end the week on Friday with easterly flow and high pressure in place with similar limited convective pattern. Temperatures in the low to mid 90s with triple digit heat indices once again today.
BW Chattanooga Airport, TN 87 71 87 72 90 / 40 30 50 20 30 Knoxville McGhee Tyson Airport, TN 86 68 88 71 90 / 30 20 30 20 30 Oak Ridge, TN 87 68 88 69 90 / 30 20 30 20 30 Tri Cities Airport, TN 84 64 86 65 89 / 20 20 20 10 30.
Temperatures will climb to the low 90s at the coast to mid 90s inland, reaching towards 95-97F in portions of Lake and western Orange counties.
932 AM EDT Fri Aug 20 2021 A broad upper level trough is expected to linger over the region through Saturday.
457 AM MDT Fri Aug 20 2021 Upper trof will be moving across the region today with widespread showers expected. This will fill in through the day as the trof moves east.
646 AM EDT Fri Aug 20 2021 Low pressure slowly pulls away to the east today while a warm and humid air mass remains in place across the area. Low pressure slowly moves east today with moisture lingering in its wake. Although the low lingers near the Midcoast or downeast Maine, model forecasts seem to favor southern NH and southwest Maine with the lingering cloud cover and if that's the case then the warmest areas will actually be near the Canadian border where mid 80s are possible. Cold front associated with the leading edge of high pressure moving southeast into the Canadian Maritimes gets hung up or washed out over the far northern parts of our area tonight into Saturday, so the cooler air doesn't really arrive.
1007 AM EDT Fri Aug 20 2021 High pressure will lead to areas of dense fog this morning. The threat for showers and thunderstorms is forecast to be isolated today under this weak high pressure.
623 AM CDT Fri Aug 20 2021 (Today and tonight) Most of the models are showing a drier forecast across West Central Texas, as the upper level ridge to the east builds westward into the area. GFS still shows a little more convection along the western and northwest border of the area late this afternoon and evening along the periphery of the ridge. Will continue the idea of isolated convection across the western Concho Valley and western Big Country for one more day before the ridge can completely build into the area. Otherwise, temperatures a little warmer than yesterday with highs mainly in the mid 90s.
Temperatures this morning are in the low 60s to near 70. Generally a dry day for most areas today, but with an upper level trough and low over the region, a few scattered showers and thunderstorms will be possible. Showers will fill in more to the east (mostly out of the area), but as the trough tracks through the northern portion of the area, additional shower development will be possible toward Lake Ontario. Low temperatures tonight will be in the low to upper 60s. A closed upper level low across the mid-Atlantic states on Saturday will interact with tropical system Henri over the weekend.
Isolated showers in the ridges, prompted by orographic lift, will too dissolve throughout the day as winds shifting from the northeast. Largely dry conditions are expected Saturday despite and upper low over the area as warm air aloft from h850 to h700 keeps convection capped. Long range deterministic models indicate that a large scale ridge should be prominent for the beginning of the week, reinforcing warm temperature. Any isolated showers this afternoon should be limited to the vicinity of MGW and the ridges. Periodic restrictions with mainly aftn convection is expected through the weekend under broad upper troughing.
Latest analysis shows an upper level trough just to our east which is expected to become a closed low later today and meander over the Mid Atlantic through Saturday. To our west, upper level ridging extends from the mid west up through the upper Great Lakes. Afternoon high temps in the low to mid 80s. The large scale pattern across the CONUS in the extended will feature a large upper trough coming onshore in the Pacific Northwest to begin the period, with a ridge of high pressure sprawled across the the Great Plains, Great Lakes, and the Ohio and Tennessee Valleys. A ridge of high pressure will be in place over New England, while tropical cyclone Henri should be somewhere off the Mid- Atlantic coast.
607 AM EDT Fri Aug 20 2021 A broad upper level trough is expected to linger over the region through Saturday.
Upper ridging this morning across SE TX into SE LA will begin to slowly build northward today through tonight and should be centered across the heart of the Four State Region on Saturday. It makes sense given the amount of rainfall our region has seen lately to undercut NBM temps just a degree or two today and similarly for Saturday given the high soil moisture content.
A trough will bring stormy weather to the silver state on Saturday along with further smoke and haze.
GOES-17 Water Vapor Imagery depicts a broad upper level trough digging southward along the British Columbia coastline this morning. Model guidance is in good agreement with this trough moving into eastern Washington late this afternoon and evening, with another round of showers and thunderstorms developing area-wide. Shower and storm activity will expand across central Idaho late Friday night into early Saturday morning as the trough axis pushes eastward across the Northern Rockies. The low looks to track across central Idaho and west-central Montana near and along the I-90 corridor.
As the mid level trough approaches from the west it lifts northeast and takes on a negative tilt.
502 AM PDT Fri Aug 20 2021 A deeper marine layer will persist into Saturday with high temperatures for today a little warmer and Saturday a little cooler.
Pattern synopsis and forecast: Mid level ridge folding into the region early this morning. with high pressure dominating the low level environment. Lake breezes once again should develop this afternoon, helping keep those shoreline areas a few degrees cooler. Expect lows tonight to only drop into the lower and middle 60s. High Impact Weather Potential: Low Pattern Synopsis: Upper-level ridging stretching from the southern Great Lakes up into Hudson Bay will continue to slide east and amplify through the weekend as Henri works its way north along the Atlantic coast.
637 AM EDT Fri Aug 20 2021 High pressure will lead to areas of dense fog this morning. The threat for showers and thunderstorms is forecast to be isolated today under this weak high pressure.
Mean layer analyses place a deep ridge complex over Gulf of Mexico and Florida, while a TUTT lumbers to the southwest over Central Cuba.
524 AM MDT Fri Aug 20 2021 The H5 trough is currently centered roughly over Thermopolis this morning, slowly drifting eastward. The trough will continue ejecting NE through the next 12 hours, Slowly drying the atmosphere in its wake. With the trough departing, the wraparound activity will be more showery in nature, with smaller areas getting any measurable precipitation. This will be brief, as the next trough drops southward into the Pacific Northwest.
BW Chattanooga Airport, TN 85 70 86 72 89 / 60 30 50 20 30 Knoxville McGhee Tyson Airport, TN 85 68 88 71 90 / 30 20 30 10 20 Oak Ridge, TN 86 68 87 69 89 / 20 20 30 20 20 Tri Cities Airport, TN 85 64 87 66 88 / 20 10 10 10 20.
/issued 323 AM CDT Fri Aug 20 2021/ A plethora of cyclones highlights the water vapor loop this morning. The most impressive is the deep trough over the Rockies, while another wave is moving slowly east across the Great Lakes. Looking to the south and east of the ridge, we find Tropical Storms Grace and Henri, which pose no threat at all to the Mid-South. We should see a lull in convective activity this evening but nocturnal showers/storms are expected to develop after midnight as the low-level jet/warm advection enhanced lift across the region.
A few northerly gusts of around 15-20 mph are occurring across the northern Sacramento Valley and surrounding foothills, and local northeast gusts of 20-30 mph are present again across the higher elevations of the northern Sierra. The highest concentrations of wildfire smoke are over the northern half of the Sacramento Valley and across the northern Sierra and foothills. The remainder of the Central Valley is expected to see improvement on Saturday as stronger westerly flow associated with the trough pushes much of the smoke off to the east. This trough is forecast to slide east through the PacNW over the weekend with less digging than the last system. The higher elevations of the northern Sierra and southern Cascades will see gustier southwest winds over the weekend which could pose problems for the Dixie Fire.
Temperatures across the area should trend a bit cooler as the first upper level trough exits the region today, with little change on Saturday as the next trough passes overhead.
This will continue to be the trend through the morning until more cumulus develops as the lower atmosphere destabilizes by noontime. Generally a dry day for most areas today, but with an upper level trough and low over the region, a few scattered showers and thunderstorms will be possible. Showers will fill in more to the east (mostly out of the area), but as the trough tracks through the northern portion of the area, additional shower development will be possible toward Lake Ontario. Low temperatures tonight will be in the low to upper 60s. A closed upper level low across the mid-Atlantic states on Saturday will interact with tropical system Henri over the weekend.
1226 PM EDT Fri Aug 20 2021 A broad upper level trough is expected to linger over the region through Saturday.
The low and wave will continue to move northeast this afternoon and evening, allowing for the rain to come to an end.
Diegan Chattanooga Airport, TN 70 86 72 89 72 / 30 50 20 30 10 Knoxville McGhee Tyson Airport, TN 68 88 71 90 70 / 10 30 10 20 10 Oak Ridge, TN 68 87 69 89 69 / 10 30 20 20 0 Tri Cities Airport, TN 64 87 66 88 66 / 10 10 10 20 10.
120 PM EDT Fri Aug 20 2021 High pressure will lead to areas of dense fog this morning. The threat for showers and thunderstorms is forecast to be isolated today under this weak high pressure.
Otherwise, a mostly nice day; stratocu should dissolve as mixing prevails in the low-levels. Dry conditions will likely stay near and to the west of Pittsburgh throughout the day tomorrow under high pressure. Temperature trends will remain at or slightly above average throughout this period under high pressure.
The low level air mass remains quite moist, indicative of dewpoints in the mid 70s to near 80 degrees as of 15Z. 1 inches across the area, only minimal mixing is expected for the afternoon, with dewpoints hard pressed to mix much below the mid 70s, as max temps climb into the lower/mid 90s. Meanwhile, flat upper ridging remains centered over S LA/SE TX, with the short term progs suggesting that it will gradually build back N into E TX/N LA later tonight. Given the flat cu field as of mid-morning, have dropped pops this morning across all but SE OK/SW AR/NE LA, where a weakness aloft lingers atop the ridge axis.