Aikyam-Lab/Synoptic-Bench huggingface dataset:
With the central Atlantic ridge building into the region, we are also seeing fairly warm low and mid-level temperatures this afternoon. Either way, lows will be in the low 70s and skies mostly clear (outside of any fog/low clouds).
1235 PM CDT Thu Aug 26 2021 (Today and tonight) The mid-level ridge overhead begins to break down today, and hot/humid conditions are expected to continue with highs in the mid- to upper-90s.
With the center of the upper ridge well to our north this is allowing for some diurnally driven afternoon isolated to scattered showers and thunderstorms. Closer to daybreak there could be some activity in the Coastal Plains associated with a weak coastal trough. Highs tomorrow will be a bit cooler, in the lower to middle 90s with some extra cloud cover. Low rain chances will linger into tomorrow night with lows in the lower to middle 70s.
Isolated convection may occur again Friday afternoon in mainly the higher terrain areas, but will keep pops below mentionable levels.
A weak cold front is moving through the area this morning, and has already passed through much of eastern Oregon.
This afternoon's high temperatures will range in the low to mid 90s across the Permian Basin and the Pecos River Valley. Subsidence from an upper lvl ridge located over the Plains will aid in keeping precip minimal across much of the region.
As temperatures drop to the low 70s later tonight, will also have to watch out for the potential for fog, given low level moisture from the rainfall and due to slow moving flow. Guidance from models continues to suggest H5 ridge amplification over the Ohio Valley for the weekend. A stalled frontal boundary will lift northward into the Great Lakes region in response to the ridge aloft becoming more amplified.
Heat indices are forecast to peak around 100 degrees throughout the Lower Susquehanna Valley once again on Friday afternoon. Scattered convection continues early this evening over the Laurel Highlands as a slow moving 5h trough approaches from the WV panhandle. Expecting activity to dissipate by mid to late evening with the loss of daytime heating, but will likely hang on longest over my southwest invof forcing from the aforementioned upper trough.
This low potential is expected to end shortly after sunset.
Heat indices are forecast to peak around 100 degrees throughout the Lower Susquehanna Valley once again on Friday afternoon. Subtle upper trough flattening the amplified upper ridge is also providing a trigger, so additional isolated activity may survive past midnight in the aforementioned areas, and updated POPs to include this. An upper level ridge will stay over our area through the rest of the weekend.
Northwesterly flow behind the upper level trough will continue to help push much of the smoke out of the region. Temperatures will be a few degrees cooler overnight. Friday will be few degrees cooler than today with temperatures in the valley reaching the upper 70s.
CAM models note these should be exiting quickly to the east as the trough pivots more northeast across MT. This wave will drag a cold front southward across the northern half of the state Friday evening.
Heat indices are forecast to peak around 100 degrees throughout the Lower Susquehanna Valley once again on Friday afternoon. Subtle upper trough flattening the amplified upper ridge is also providing a trigger, so additional isolated activity may survive past midnight in the aforementioned areas, and updated POPs to include this.
Lows will drop into the upper 60s for portions of northwest Arkansas while everywhere else will see lows mainly in the low to mid 70s. It will be another hot day tomorrow, though it should be slightly cooler than previous days as the mid/upper ridge weakens a bit overhead.
/issued 225 PM CDT Thu Aug 26 2021/ SHORT TERM (Now through Friday Night): Seabreeze-induced convection continues develop along the coastal counties while midlevel ridging over the Southern and Central Plains slowly lifts northward. A similar setup for seabreeze convection can be expected on Friday, especially with the midlevel ridge weaker and moving farther northeast away from the BRO CWA.
656 PM CDT Thu Aug 26 2021 (This evening through Friday) The upper level ridge from the southwestern states across the southern Plains is on a weakening trend.
Overnight lows are expected to fall into the low to middle 70s. Temperatures should be slightly cooler tomorrow, but some heat indices may approach 105 degrees again. Otherwise, rain free conditions and mostly sunny skies prevail across the Mid-South this afternoon with temperatures as of 3 PM CDT in the lower to middle 90s at most locations. Few changes from earlier forecasts, as a broad upper level high pressure ridge brings clear skies and light winds. With little change in the upper ridge position and strength, 850mb temps and precipitable water values will change little on Friday.
A weak cold front continues to move through the rest of today. The upper level low will move out of the area later Friday. High pressure will build through the weekend.
Attention will turn to the NW for the remainder of the evening as clusters of storms are ongoing across portions of Iowa and expected to further expand in coverage as the low level jet ramps up this evening. While areas along I-74 should also have a heat index around 100, the cooler conditions there today has interrupted the duration string that is one of the issuance criteria. Upper level high pressure will be centered over the Carolinas this weekend, which should help drive much of the convective activity northward into the western Great Lakes.
922 PM CDT Thu Aug 26 2021 The TN Valley this evening lies on the western periphery of a broad subtropical ridge centered off the Carolina coast.
1010 PM EDT Thu Aug 26 2021 Cape wind profilers show deep E/SE flow across the area between high pressure to the northeast off the Carolina coast and T. It will be another warm and sultry day for east central Florida, with highs in the low 90s across the interior, and upper 80s along the coast. Pressure gradient will support E/SE flow 12 to 15 knots between high pressure along the Carolina coast and T. High pressure over the western Atlantic will drift towards the Carolina coast through the day on Friday.
Upper high that was firmly entrenched across the central plains yesterday has weakened considerably. Meanwhile, upper high development is now commencing off the southern Atlantic coast. A ridge weakness is now more apparent across the mid state and we are seeing some isol to sct convection across the Plateau area at this time. On Friday, that upper high off the Atlantic coast will strengthen with ridging stretching westward toward the mid state by afternoon.
Through 03Z, isolated mountain obscurations may be encountered over the higher peaks from NC and NW areas to the Gila region along with very localized MVFR cigs/vsby in the strongest storms.
Afternoon humidity falling to the low teens this afternoon as well. Front finally looks to move into the area this evening with winds shifting northeast and cooler air moving into the CWA after 06Z tonight. Upper high that has been in control of our weather shifts east and longwave trough over the west allows systems to move into the area. A stalled out cold front lays across central WYoming this morning.
1155 PM MDT Thu Aug 26 2021 Aviation Section Updated It will be a cooler day today, along with scattered rain showers or isolated thunderstorms, with most of the precipitation falling this afternoon.
(Today through Saturday afternoon) An upper trough extends from the Pacific Northwest to the northern Plains. This has resulted in the weakening of the upper ridge over West Texas and Southeast New Mexico. Isolated showers and thunderstorms are possible mainly across the Lower Trans Pecos, Big Bend, Davis Mountains, and Guadalupe Mountains.
Another hot and humid day ahead with max temps topping out again in the low 90s. A few isolated showers and storms expected across the high terrain this afternoon but valley locations should stay dry as subsidence increases as an area of high pressure moves into the Carolinas.
An upper level trough will traverse the northern plains Saturday evening. Other thunderstorms could develop in central Kansas Saturday night on the nose of the low level jet near the surface front.
Showers/thunderstorms associated with an approaching inverted trof have been expanding in coverage across our coastal waters tonight.
00z GFS/ECMWF/NAM continue to show upper level trough digging over the Northern Plains States Saturday into Saturday night and southwesterly flow aloft over the forecast area. With upper level trough well west of the forecast area. The forecast area will be on the eastern periphery of these pieces of energy Saturday and main surface front/upper level trough tracks over the forecast area Saturday night. expect the higher likelihood of convection chances to occur Saturday evening/night. With the main pieces of energy west of the forecast area and surface front/upper level trough moving over the forecast area during the night time hours.
312 AM CDT Fri Aug 27 2021 Southerly breezes underneath a broad upper level ridge was ongoing across much of the southern and central Plains overnight.
416 AM EDT Fri Aug 27 2021 High pressure off the coast of the Carolinas will remain in control through the short term period bringing waves of moisture out of the ESE today and into tomorrow into South and Central Georgia. Overnight lows will remain around 70 with cooler temps in the mountains.
temps will be 2-4 deg cooler than seen Thu afternoon. Highs on Sat will be a bit cooler as well due to the increased cloud cover and POPs.
Slightly cooler conditions are expected through the weekend.
The TN Valley this evening lies on the western periphery of a broad subtropical ridge centered off the Carolina coast.
Otherwise today should be a warm with temperatures in the low 90s and heat indices reaching into the low 100s.
An upper trough approaching the area will be sending a couple upper disturbances through. The upper trough will lift to the northeast Saturday but NW winds may be strong enough on the backside for a Lake Wind Advisory.
Otherwise, ingested the last several hours worth of temperature and dewpoint observations and interpolated through to morning lows in the low to mid 70s areawide.
1243 AM CDT Fri Aug 27 2021 (This evening through Friday) The upper level ridge from the southwestern states across the southern Plains is on a weakening trend.
341 AM CDT Fri Aug 27 2021 The upper pattern remains largely unchanged from yesterday afternoon, with broad ridging across the Southern/Central Plains and into the northeastern seaboard. During the daytime hours, southerly winds become breezy as the lee trough deepens and tightens the pressure gradient, continuing to bring in plenty of warm air. By evening, the aforementioned upper trough swings through the Upper Midwest while the next one comes out of the Pacific Northwest.
Southerly winds will continue for much of today, resulting in additional moistening of the lower atmosphere and slightly cooler temperatures compared to yesterday.
We should see an uptick in afternoon convection across the region during this time with the highest storm chances across our Central and Eastern counties. A little more cloud cover should tend to hold temperatures into the lower 90s on Saturday.
Slightly cooler afternoon highs will follow for today.
Temps will warm quickly under mostly clear skies, with highs maxing out in the lower 90s. The upper ridge, anchored off of the coast of the Carolinas, with build to the west today, with flow aloft becoming more southeasterly. Moisture will be a bit less today given the more easterly component to the flow, and with more subsidence from the ridge, only isolated thunderstorms are expected this afternoon and these will mainly be south of the TN River. The upper ridge will move westward over the weekend, while Tropical Storm Ida approaches the LA coastline and strengthens to a hurricane.
Expect this will enhance convergence along synoptic scale warm front to serve as a focus for vigorous convection this evening into tonight. Storms are expected to move into eastern Nebraska with some lingering showers/thunder in elevated instability though the low level jet axis will be shifting to our east. An upper level trof will push a strong cold front through Nebraska on Saturday.
400 AM EDT Fri Aug 27 2021 Strong high pressure building in from Bermuda will bring hot temperatures through the weekend, along with relatively dry weather. There has been little change to this portion of the forecast - strong high pressure at the surface and mid levels continues to build west from the Atlantic Ocean over the Carolinas. With the location of the high, most moisture should rotate around (and away from) central North Carolina.
Meanwhile, back south in our part of the world, an elongated ridge of high pressure in the middle troposphere continued to prevail. it will essentially be more of the same as the broad leeside trough will remain in place across Colorado into southeast Wyoming/far western Nebraska. On Saturday, the setup does not look all that different as the entire southwest/west central Kansas region will remain in south surface winds with the leeside trough still holding out west across Colorado.
This will result in cooler temperatures Friday and Saturday (and I use that term loosely). Upper level ridging will start to break down.
Cloud cover around the Tri-Cities through much of the day has kept our temperatures just a few degrees cooler, but these clouds have finally started to erode and lift northeast. There will be some small chances for lingering thunderstorms, but the big story is that it will be much more pleasant with cooler highs only around 80 over southern Nebraska, to the lower and middle 80s over north central Kansas. The overall upper level pattern will start out fairly zonal, but we will see a building upper ridge across the southern plains that will push north into the central plains allowing for a decent warm up.
At the surface, an area of low pressure sits to our southwest, and a boundary stretches across southern SD. This afternoon, an approaching trough will skirt northwestern SD, and a cool front will begin crossing the CWA. More storms will be possible on Saturday, as another wave rounds the base of the upper trough.
CAM models note these should be exiting quickly to the east as the trough pivots more northeast across MT. This wave will drag a cold front southward across the northern half of the state Friday evening. On Saturday a trough will swing across the state, with a weak cold front dropping down from the north.
Much of the guidance is pegging the intensity on the higher end, and the Gulf is currently very favorable conditions with warm SST, moist air and little wind shear, so there is very little to impede Ida. A inverted trough axis will continue to push across the Gulf South tonight through tomorrow.
Southeastern areas have the highest chance of precipitation, mainly across the Hill Country and Heartland, or areas southeast of a Brownwood to Sonora line. High temperatures across the area today will peak in the lower to mid 90s, with overnight lows in the upper 60s to low 70s.
204 AM EDT Fri Aug 27 2021 TS Ida in the NW Caribbean Sea will begin to influence the local weather today as pressure gradient tightens and easterly steering flow increases with the highest scattered showers and storms coverage along the coast this afternoon.
A midlevel jet streak will round the base of the trough to our immediate west this afternoon, initiating thunderstorms off the higher terrain in northeastern Wyoming and southeastern Montana before moving into the western Dakotas. Temperatures will remain on the cool side today with highs in the lower 60s northeast to the upper 70s southwest. Precipitation chances linger through the early part of the day on Saturday, especially central and east, as the base of the upper trough moves overhead and eventually off to the northeast by Saturday night.
SHORT TERM (Now through Saturday): A weak inverted 500 mb trough will approach Deep South Texas and the Rio Grande Valley from the east and then linger over the area. These two features, combined with daytime heating, will result in isolated to scattered showers and thunderstorms through the period, with the best chances generally over the eastern portion of the BRO CWFA, especially the lower Texas coastal waters.
Afternoon highs are expected to top out in the low to mid 90s, with heat indicies in the low 100s, just shy of Heat Advisory criteria.
High pressure will build for the weekend for sunshine.
The HRRR continues to be on the more aggressive/farther north solution, with the potential of storms mainly near the Missouri River around 05-06Z (mainly south of Mobridge). To start the period, an upper trof will be advecting across the Dakotas Saturday and Saturday night. The main low level boundary associated with the upper trof will stretch from ne-sw across eastern South Dakota by afternoon.
High pressure building in from the east and weak subsidence inversion will keep PoPs to slight chance this afternoon across the Midlands. Upper level ridging will increase overnight with clearing skies late in the evening.
606 AM CDT Fri Aug 27 2021 The Heat Advisory continues today with upper level ridging over the region along with south-southwest winds. Maximum heat indices of 100 to 105 can be expected this afternoon with highs in the low to mid 90s and dew points in the low to mid 70s.
The upper high/ridge will continue to expand west over the Carolinas today, and although drier air is in place this morning, slightly better moisture will arrive later this afternoon. The upper ridge will move westward over the weekend, while Tropical Storm Ida approaches the LA coastline and strengthens to a hurricane.
Persistent ridging aloft and weak low-level pressure gradient will result in weak flow through a deep layer of the atmosphere. Max temps will run in the lower 90s for most, with the urban heat island of Louisville likely to reach the mid 90s.
916 AM EDT Fri Aug 27 2021 High pressure over the Atlantic and extending southwest along the Mid Atlantic coast combined with Tropical Storm Ida over the northwest Caribbean Sea is supporting an increasing east southeast wind flow over the region early this morning as the pressure gradient slowly tightens over the region. A tightening pressure gradient between high pressure over the Atlantic and extending southwest along the Mid Atlantic coast and Tropical Storm Ida over the Northwest Caribbean Sea will support an increasing east to southeast wind flow and slowly building seas over the Gulf waters the remainder of today.
/Issued 416 AM EDT Fri Aug 27 2021/ High pressure off the coast of the Carolinas will remain in control through the short term period bringing waves of moisture out of the ESE today and into tomorrow into South and Central Georgia. Overnight lows will remain around 70 with cooler temps in the mountains.
High pressure building in from the east and weak subsidence inversion will keep PoPs to slight chance this afternoon across the Midlands. Temperatures around climatology in the low 90s. Upper level ridging will increase overnight with clearing skies late in the evening.
635 AM EDT Fri Aug 27 2021 Strong high pressure building in from Bermuda will bring hot temperatures through the weekend, along with relatively dry weather. There has been little change to this portion of the forecast - strong high pressure at the surface and mid levels continues to build west from the Atlantic Ocean over the Carolinas. With the location of the high, most moisture should rotate around (and away from) central North Carolina.
428 AM CDT Fri Aug 27 2021 The Heat Advisory continues today with upper level ridging over the region along with south-southwest winds. Maximum heat indices of 100 to 105 can be expected this afternoon with highs in the low to mid 90s and dew points in the low to mid 70s.
The upper pattern remains largely unchanged from yesterday afternoon, with broad ridging across the Southern/Central Plains and into the northeastern seaboard. During the daytime hours, southerly winds become breezy as the lee trough deepens and tightens the pressure gradient, continuing to bring in plenty of warm air. By evening, the aforementioned upper trough swings through the Upper Midwest while the next one comes out of the Pacific Northwest.
405 AM MDT Fri Aug 27 2021 Aviation Section Updated It will be a cooler day today, along with scattered rain showers or isolated thunderstorms, with most of the precipitation falling this afternoon.
The cooler air and increased cloud cover associated with this feature will keep temperatures well below normal for this time of year.
With weak high pressure above, moisture looks to sneak back into the region increasing thunderstorm chances.
407 AM CDT Fri Aug 27 2021 A weak area of low pressure will track from north central Nebraska this morning to northwest Iowa by this afternoon. This will drag a weak cold front across the area this morning, but that front pretty much washes out by this afternoon as it moves into eastern Nebraska. The low will migrate east-northeast through the day and be located across far southeast South Dakota by late Saturday afternoon. Appears there is some threat for scattered late afternoon surface based convection along the cold front, which should extend from near O'Neill to Thedford to Sidney by late afternoon.
LFT and ARA have the highest chances for storms today.
Did make some minor updates to PoPs for the afternoon with slight chances residing across the higher terrain most likely. SR Chattanooga Airport, TN 92 72 90 72 90 / 20 10 20 10 30 Knoxville McGhee Tyson Airport, TN 92 71 92 71 92 / 10 10 10 0 20 Oak Ridge, TN 91 71 92 71 91 / 20 10 10 10 20 Tri Cities Airport, TN 91 67 92 67 91 / 20 10 10 10 30.
/issued 252 AM CDT Fri Aug 27 2021/ SHORT TERM (Now through Saturday): A weak inverted 500 mb trough will approach Deep South Texas and the Rio Grande Valley from the east and then linger over the area. These two features, combined with daytime heating, will result in isolated to scattered showers and thunderstorms through the period, with the best chances generally over the eastern portion of the BRO CWFA, especially the lower Texas coastal waters.
636 AM CDT Fri Aug 27 2021 A weak area of low pressure will track from north central Nebraska this morning to northwest Iowa by this afternoon. This will drag a weak cold front across the area this morning, but that front pretty much washes out by this afternoon as it moves into eastern Nebraska. The low will migrate east-northeast through the day and be located across far southeast South Dakota by late Saturday afternoon. Appears there is some threat for scattered late afternoon surface based convection along the cold front, which should extend from near O'Neill to Thedford to Sidney by late afternoon.
/issued 204 AM EDT Fri Aug 27 2021/ TS Ida in the NW Caribbean Sea will begin to influence the local weather today as pressure gradient tightens and easterly steering flow increases with the highest scattered showers and storms coverage along the coast this afternoon.
343 AM MDT Fri Aug 27 2021 The back edge of the upper trof axis now moving across central Colorado with a drier and more subsident airmass expected across the entire area this morning. Temperatures will be warmer today as 700mb temperatures rise to around +17c. This will result in readings back into the lower to mid 90s across the plains. At the same time, there will be moistening of the low levels, but the airmass should remain largely capped off with the slightly cooler boundary layer.
359 AM MDT Fri Aug 27 2021 It will be a cooler day today, along with scattered rain showers or isolated thunderstorms, with most of the precipitation falling this afternoon.
600 AM CDT Fri Aug 27 2021 Southerly breezes underneath a broad upper level ridge was ongoing across much of the southern and central Plains overnight.