Aikyam-Lab/Synoptic-Bench huggingface dataset:
As upper trough moves into the eastern Tennessee today showers starting to increase from west to east. TD Chattanooga Airport, TN 87 68 90 71 92 / 40 20 10 0 20 Knoxville McGhee Tyson Airport, TN 87 66 90 70 92 / 60 20 10 0 20 Oak Ridge, TN 86 65 89 69 91 / 60 20 10 0 20 Tri Cities Airport, TN 85 62 88 66 90 / 50 20 20 0 20.
1217 PM PDT Sat Aug 7 2021 Above average temperatures this weekend due to high pressure aloft.
It appears there will be no lack of low level or deep layer instability around today/this evening for strong convection as this western NoDak upper level low moves across the region. It's the low level and deep layer shear that is the biggest question mark still looming out there. A well defined upper level trough will provide the necessary overarching forcing for storm development/maintenance. Meanwhile at the surface, a trough will set up. Most suggest a warm front extending out of far NE SD and across MN with a trailing cold front across central to eastern South Dakota. Very slow movement to the east with this trough and associated fronts.
Continue to analyze the cold front progression for Sunday. A cold front will pass through the area with showers and a slight chance of thunderstorms across the central Idaho mountains and Baker County Oregon.
These two areas of low pressure are forecast to work northeast toward the Great Lakes region over the next 12 to 24 hours, and would likely be the lift aloft that aides thunderstorm development across the far eastern CWA (on/near the surface warm front) by early this evening. And, large hail, damaging winds and heavy rainfall along and east of a line from Mobridge to Miller are all the primary threats with any strong to severe storms there.
402 PM EDT Sat Aug 7 2021 Showers and a few thunderstorms over mainly northern areas will diminish this evening, and moist, calm air overnight will support areas of fog in the wake of a weak cold front.
1141 AM MDT Sat Aug 7 2021 Current surface analysis shows cold front laying across central Colorado early this morning. Southeast Wyoming and Nebraska Panhandle on the cooler north side of this front. Nice day today expected across the area as high pressure builds slowly back into the area. Upper high continues to build back over the area SUnday with 700mb temperatures climbing from +8C this morning to +18C Sunday afternoon.
319 PM CDT Sat Aug 7 2021 This afternoon a midlevel trough was located from the western Dakotas into northeast Colorado at 1930Z. The mid level trough will gradually move east tonight increasing forcing for ascent across the Central Plains. The trough axis moves slowly across eastern Kansas later tonight and Sunday exiting in the afternoon. Little relief from the heat will be noted on Sunday with highs in the low to mid 90s common.
116 PM EDT Sat Aug 7 2021 Scattered showers and a few thunderstorms are possible today and Sunday with a passing trough. Upper trough will pivot across the region through tonight. While the CAMs are struggling with storm development early on, it does appear that a weakening vort max/area of deformation between the trough and the low over NC/VA may be the focus for a few storms adjacent to the higher terrain early before additional storms develop and transition into the Upper Ohio Valley this evening.
High temperatures are expected to be in the low to upper 90s with low temperatures in the low to upper 60s.
Showers and thunderstorms are ongoing across our southern Middle Tennessee counties associated with the upper-level trough moving through. Shower and thunderstorm activity should mainly be confined to the I-65 corridor eastward today as the trough moves off to the east.
Not out of the question pulse storms will occur, but this area in SE ND a tad cooler than northern RRV and not yet at convective temperature which is upper 80s. Northwesterly flow returns as a ridge flattens out in the west.
Latest water vapor imagery is showing the upper ridge moving across the area which is providing the dry day to the area. The increased ascent from the trough with along pockets of low level moisture convergence will be enough to cause shower and thunderstorm development tonight that will move eastward.
1202 PM MDT Sat Aug 7 2021 Current surface analysis shows low pressure over south central SD, with cold front extending to the south of the area. Upper level analysis shows positively tilted trough now across WY, eastern MT and into western ND. Upper trough will move east across the region through late today, with low pressure and front slowly moving east of the forecast area. High temperatures will be in the 80s to around 90 degrees over the plains, with 70s over the higher Black Hills. Much warmer air returns for Sunday, ahead of a stronger cold front moving across the Rockies.
Cloud cover continues to clear out behind this system with smoke still blocking out the blue of the sky over most of the area. Conditions dry out for the day Sunday with hot temperatures returning and highs reaching the low to mid 90s for most of the forecast area.
No real good news at this point with poor air quality likely to persist as high pressure over the Great Basin continues to guide the dense smoke across the Great Basin and then driving it southeast across Eastern Utah and Colorado. The good news about the smoke is that it's helped to knock temps down a few more degrees off the already cooler forecast temps for today.
Broad, mid level ridging will persist over the area in the short term with high pressure dominating the Northwest Gulf.
Satellite imagery also showed the upper level trough axis east of of Mississippi with a rather dry northwest flow aloft across the region. Surface analysis has a weak ridge across our CWA. The forecast remains on track with a dry day topping out a few degrees warmer than yesterday.
(Sunday night through next Saturday) Typical summertime pattern expected across the region through the upcoming week, as the subtropical ridge dominates our weather.
Trough axis settles across Sunday night so this should keep the thunderstorm threat going.
A cold front was also pushing south through northeast Colorado into far northwest Kansas. while deep layer shear has also increased, the highest values (40 kts) are confined to northwest Kansas with values around 25-30 kts located over southwest Kansas. Latest satellite imagery is now starting to show some cumulus and isolated thunderstorm development off the higher terrain in eastern Colorado. The cold front will continue moving south and east tonight into Sunday morning and should be washing out over south central Kansas or northern Oklahoma by Sunday afternoon. Temperatures on Sunday should be similar to todays, if not a few degrees cooler in the mid/upper 90s.
Upper ridging now in place will help keep the remaining area rain free and warm, with temperatures nearing normal.
Temperatures will remain near climate normals with lows in the mid 70s inland to lower 80s along the coast and highs in the lower to mid 90s on Sunday.
151 PM EDT Sat Aug 7 2021 Ridging to the south has caused a south to southwest flow once again. The ridge will start to shift north on Sunday.
CD Chattanooga Airport, TN 68 90 71 92 72 / 20 10 0 20 20 Knoxville McGhee Tyson Airport, TN 66 90 70 92 71 / 20 10 0 20 10 Oak Ridge, TN 65 89 69 91 70 / 20 10 0 20 10 Tri Cities Airport, TN 62 88 66 90 67 / 20 20 0 20 20.
CNM and HOB may see an isolated thunderstorm late this afternoon and early evening, but confidence of eastward progression of this activity off the higher terrain and into those terminals is low at this time. Will amend for VCTS/TSRA should any thunderstorms move off the higher terrain towards those terminals. Winds will remain elevated tonight with the low-level jet. A disturbance associated with the upper trough will pass over New Mexico today, resulting in some convection across the Sacramento Mountains. Sunday will be slightly warmer than Saturday with highs in the upper 90s across the Permian Basin and 100s along the Trans Pecos and Rio Grande. Storms look to develop off the higher terrain of SE New Mexico and attempt to move into TX, but drier air in the mid levels will kill off storms fairly quickly.
1054 AM MDT Sat Aug 7 2021 Compared to recent days, today's weather should be fairly benign as a low-amplitude ridge builds over the region.
These storms are associated with an upper-level trough that is moving off to the east, therefore, we're not expecting any additional development across northwest Alabama or southern Middle Tennessee. As the upper-level trough continues to move off to the east, shower and thunderstorm activity should move out of Alabama by around sunset, leaving us with dry weather and clearing skies later tonight. With high pressure starting to build in behind the trough, expect temperatures to get a bit warmer with highs getting up into the upper 80s to lower 90s.
Attention remains focused on the stronger storm system and cold front set for tomorrow evening.
1034 AM CDT Sat Aug 7 2021 An upper trough is moving through Middle Tennessee this morning. As a result, some clouds are beginning to develop along the Tennessee River as this area remains on the western periphery of the trough. Highs will range in the mid 80s to the lower 90s. Warmer temperatures are on tap for the next several days. Today, a ridge will build in across the Mississippi River Valley.
247 PM MDT Sat Aug 7 2021 Latest visible loop was showing the upper level trof continuing to spin over the Nebraska panhandle. It is interesting to see land cloud fire satellite loop that the majority of this smoke is trapped underneath this trof where the greatest amount of subsidence has been today. Would expect this trof to continue to pivot east out of the forecast area this evening. There is also some pockets of isolated showers and thunderstorms developing over the higher terrain, but this convection should dissipate fairly quickly as sunset approaches. We should see much better mixing on Sunday as the upper level ridge builds over the area. This should help the surface smoke disperse fairly quickly tomorrow morning, but will probably see elevated smoke which may tend to keep temperatures slightly cooler than the NBM.
234 PM EDT Sat Aug 7 2021 It would seem that Mother Nature is taunting us when looking at the BYX radar, especially the lower Keys. A few of these showers have managed to pass over portions of the middle and upper Keys, but just coming shy of the lower Keys. As the same time, the Bermuda high will slowly be gaining strength, which in turn will aid in pivoting the ridge axis further north. This is likely due to how each model is trying to resolve pockets of dry air in the lower to mid levels that may inhibit shower potentials.
Across northwest Montana, clouds have begun to increase; signaling a change to much cooler and wetter conditions expected for much of the region on Sunday.
1237 PM EDT Sat Aug 7 2021 Scattered showers and a few thunderstorms are possible today and Sunday with a passing trough. Upper trough will pivot across the region through tonight. While the CAMs are struggling with storm development early on, it does appear that a weakening vort max/area of deformation between the trough and the low over NC/VA may be the focus for a few storms adjacent to the higher terrain early before additional storms develop and transition into the Upper Ohio Valley this evening.
96" reflects a drier profile aloft as upper level high pressure builds into S. Meanwhile a low level high pressure over the Gulf Coast will lead to tighter gradients, and an increased South to Southeasterly flow tonight will advect low level moisture bumping up dewpoints slightly for tomorrow.
247 PM CDT Sat Aug 7 2021 As one trof departs to the east, another approaches from the west. We are sandwiched between the two, under a teleconnected ridge, for the first half of the forecast, before slowly giving way to the 2nd trof and its associated impacts, during the latter half of the forecast.
340 PM EDT Sat Aug 7 2021 An upper longwave trough was crossing the state this afternoon. The trough should continue to push eastward during the night with ridging taking place across the area on Sunday and Sunday night.
144 PM EDT Sat Aug 7 2021 Scattered showers and a few thunderstorms are possible this evening and Sunday with a passing trough. Upper trough will pivot across the region through tonight. Despite the trough, the forcing mechanisms present for organized convection are rather weak. As such, kept PoPs in the chance category, with the higher values coming as the axis approaches.
1122 AM MDT Sat Aug 7 2021 Compared to recent days, today's weather should be fairly benign as a low-amplitude ridge builds over the region.
Lows tonight expected to be in the lower 70s inland and mid to upper 70s near and along the coast. Highs on Sunday primarily in the lower 90s but a few upper 80s along the coast with the enhanced onshore flow off the Gulf resulting from the afternoon sea breeze.
Firstly, high-res CAMs suggest development along the weak cold front setting along our western periphery.
/issued 1034 AM CDT Sat Aug 7 2021/ An upper trough is moving through Middle Tennessee this morning. As a result, some clouds are beginning to develop along the Tennessee River as this area remains on the western periphery of the trough. Highs will range in the mid 80s to the lower 90s. Warmer temperatures are on tap for the next several days. Today, a ridge will build in across the Mississippi River Valley.
The weather may not be as tranquil for the rest of the weekend as an upper trough will move into the area Sunday afternoon.
Main upper trough axis swings through on Sunday allowing for a much drier mid level and far decreased coverage of thunderstorms, which will tend to favor the seabreeze but could occur with isolated coverage just about anywhere as the mid level trough still appears to offer a form of ascent. The short term period will be relatively quiet as mid mid level ridging slowly builds in from the Eastern Atlantic with Bermuda High Pressure at the surface. Certainly no change in air mass with the lethargic late summer time pattern with highs within 90 both days and seasonal lows in the lower 70s. Some slow changes will occur later in the period/week as a better defined inland trough develops increasing winds and seas slightly.
255 PM EDT Sat Aug 7 2021 Current water vapor imagery reveals upper trough axis over the eastern half of the Commonwealth with visible imagery showing fair weather cu field popping up over the region as earlier mid-level clouds exit east of our CWA. KY Mesonet and regional observations show temperatures in the low 80s in our eastern counties due to cloud cover and in the mid 80s elsewhere. Clouds will clear overnight with Sunday morning min temps in the mid to upper 60s with Louisville Metro in the low 70s.
Over scentral SD, lingering instability ahead of a secondary trough may allow a shower or storm, but chances for this are not that great. Strong upper trough will push into the northern Rockies Sunday with front side WAA over the region. Upper trough will shift east with a strong cold front settling into the NW half Sunday night.
The focus then shifts to Sunday as an upper low moves east out of Washington into the Northern Rockies, pushing a strong cold front south and east through the area during the late afternoon and evening. Ahead of the cold front, pre-frontal conditions will allow temperatures to approach 100 degrees and RH values to drop well into the teens with gusty south to southwest winds. As the aforementioned low continues to move into Montana, showers and thunderstorms look to develop Sunday evening, mainly behind the cold front.
This afternoon a midlevel trough was located from the western Dakotas into northeast Colorado at 1930Z. The mid level trough will gradually move east tonight increasing forcing for ascent across the Central Plains. The trough axis moves slowly across eastern Kansas later tonight and Sunday exiting in the afternoon. Little relief from the heat will be noted on Sunday with highs in the low to mid 90s common.
Isolated storms will develop each day along the higher terrain, with the greatest chance in the White Mountains. High pressure aloft stretches from southern California through southern New Mexico this afternoon with a drier westerly flow encompassing Arizona.
Current water vapor imagery reveals upper trough axis over the eastern half of the Commonwealth with visible imagery showing fair weather cu field popping up over the region as earlier mid-level clouds exit east of our CWA. KY Mesonet and regional observations show temperatures in the low 80s in our eastern counties due to cloud cover and in the mid 80s elsewhere. Clouds will clear overnight with Sunday morning min temps in the mid to upper 60s with Louisville Metro in the low 70s.
A cold front will move through on Sunday. The passage of the cold front and upper trough on Sunday will push the smoke south of the area by Sunday evening. A cold front will pass through the area on Sunday with scattered showers and a slight chance of thunderstorms across the central Idaho mountains and in Baker County Oregon. Smoke layers aloft will decrease from northwest to southeast on Sunday evening behind the cold front.
The upper trough responsible for the convection today is moving east with showers/storms already dissapated with sky clearing. Surface ridging over the area will produce calm winds. For Saturday, upper ridging will build into the area helping to surpress convection development. Besides the fog, convection is slowly diminishing across the region as upper trough axis moves east and loss of daytime heating. Surface ridging will keep winds light and less than 10kts through the forecast period. Chattanooga Airport, TN 68 90 71 91 73 / 20 10 0 30 10 Knoxville McGhee Tyson Airport, TN 65 91 71 91 71 / 20 10 0 20 10 Oak Ridge, TN 65 90 69 91 71 / 20 10 0 20 10 Tri Cities Airport, TN 60 88 66 90 68 / 20 10 0 20 10.
459 PM PDT Sat Aug 7 2021 Updated Air Quality Issues section Above average temperatures this weekend due to high pressure aloft.
As one trof departs to the east, another approaches from the west. We are sandwiched between the two, under a teleconnected ridge, for the first half of the forecast, before slowly giving way to the 2nd trof and its associated impacts, during the latter half of the forecast.
Much warmer and humid airmass has settled into the Four State Region with the aid of a southerly boundary layer with much higher sfc dewpoints noted this evening compared to 24 hours ago. Temps are also a little warmer as well which is handled well in the current forecast. With a slightly warmer night forecast overnight across the Four State Region and with hourly temperatures running a degree or two above those last night at this time, no update to the forecast is necessary attm.
1042 PM EDT Sat Aug 7 2021 A weak trough of low pressure will slowly cross the area through the rest of the weekend, bringing a chance for scattered showers and thunderstorms mainly during the afternoons and evenings. A few showers may linger east of Lake Ontario Sunday morning as the trough axis lies on the eastern periphery of the area. Daytime highs will reach the low to mid 80s, though slowly climbing dewpoints will make it feel a bit more humid. A second mid level trough is seen over the Ohio Valley.
811 PM CDT Sat Aug 7 2021 The upper level trough axis is now to the east of the Tennessee Valley with a stalled frontal boundary along the northern Gulf Coast. Dry air is moving in behind the departing trough with PW values down around 1. With high pressure starting to build in behind the trough, expect temperatures to get a bit warmer with highs getting up into the upper 80s to lower 90s.
526 PM MDT Sat Aug 7 2021 Latest visible loop was showing the upper level trof continuing to spin over the Nebraska panhandle. It is interesting to see land cloud fire satellite loop that the majority of this smoke is trapped underneath this trof where the greatest amount of subsidence has been today. Would expect this trof to continue to pivot east out of the forecast area this evening. There is also some pockets of isolated showers and thunderstorms developing over the higher terrain, but this convection should dissipate fairly quickly as sunset approaches. We should see much better mixing on Sunday as the upper level ridge builds over the area. This should help the surface smoke disperse fairly quickly tomorrow morning, but will probably see elevated smoke which may tend to keep temperatures slightly cooler than the NBM.
653 PM EDT Sat Aug 7 2021 Scattered showers and a few thunderstorms are possible this evening and Sunday with a passing trough. Upper trough will pivot across the region through tonight. Despite the trough, the forcing mechanisms present for organized convection are rather weak. As such, kept PoPs in the chance category, with the higher values coming as the axis approaches.
As a low pressure system to our north pushes inland we will likely see increasing surface pressure gradients leading to increased onshore flow over the region.
936 PM EDT Sat Aug 7 2021 500mb analysis shows a longwave trough stretching from the eastern Great Lakes through the Middle Atlantic to the Gulf Coast. /Issued 340 PM EDT Sat Aug 7 2021/ An upper longwave trough was crossing the state this afternoon. The trough should continue to push eastward during the night with ridging taking place across the area on Sunday and Sunday night.
/Issued 340 PM EDT Sat Aug 7 2021/ An upper longwave trough was crossing the state this afternoon. The trough should continue to push eastward during the night with ridging taking place across the area on Sunday and Sunday night.
Marine observation platforms are recording winds ranging from 4 to 10 knots, with the low-level ridge axis remaining over South Florida. From synopsis, A ridge of high pressure stretches west across Florida, which is supporting light to gentle east to southeast breezes across the coastal waters of the Florida Keys. Breezes will freshen tonight through Sunday night as the ridge axis broadens and lifts northward.
946 PM CDT Sat Aug 7 2021 Wx map shows weak high pressure ridging across the Gulf, with light south to southeast winds across the region. Definitely higher dewpoints this evening, averaging in the mid to upper 70s, with temperatures in the lower 80s. Forecast has this highlighted well.
902 PM EDT Sat Aug 7 2021 Scattered showers and a few thunderstorms are possible again on Sunday with a passing trough.
Still expect activity will begin to weaken as storms approach the area late tonight as atmosphere continues to stabilize with nose of warmer air in the 900-850 MB layer remaining.
This activity will then converge toward the center of forecast area later in the day, but overall chances will be on the lower side due to drier air. The high will build more to the northeast on Monday, which will result in more of a flow from the east.
Monday is expected to hold even warmer temperatures, with areas near the South Dakota border reaching over 100 degrees.
Increasing southerly winds and warm air advection are expected ahead of the next low pressure system Monday afternoon. Cooler air will sweep in on Monday after a strong frontal boundary moves through, with more seasonal temps and mostly dry conditions to continue all week. The west CONUS ridge will slowly shift east by the weekend.
Upper trof moving through the Pac NW and brushing Norcal on Sun will eventually push the smoke Ewd, with clearing likely by or during the evening in the Srn half of the Vly as onshore flow increases. As a low pressure system to our north pushes inland we will likely see increasing surface pressure gradients leading to increased onshore flow over the region.