Aikyam-Lab/Synoptic-Bench huggingface dataset:
A broad upper trough over the western states will help initiate scattered thunderstorms over south-central Montana later today that will move across our SE zones later tonight.
Thursday will be slightly cooler, but highs will still be near 100 in most places. Upper level ridging will gradually move off to the east by the weekend.
943 AM MDT Wed Aug 25 2021 Smoky skies cover most of the area this morning, and we will see little to no improvement today, but a cold front tonight into early Thursday will start to push the smoke off to the east.
Deep ridging continues to dominate across the southern Appalachian region this morning with abundant isolation favoring modest warming. CDG Chattanooga Airport, TN 72 90 71 89 71 / 10 40 10 20 10 Knoxville McGhee Tyson Airport, TN 71 92 70 91 70 / 20 40 10 20 0 Oak Ridge, TN 71 91 69 89 70 / 10 40 10 20 0 Tri Cities Airport, TN 68 91 66 90 66 / 30 40 10 20 0.
1132 AM MDT Wed Aug 25 2021 18Z TAF CYCLE Isolated -SHRA/TS will develop near the high terrain of southern NM from 22Z to 02Z.
Attention this evening is on a weak low pressure area/MCV exiting IA and entering IL.
The latest surface analysis shows high pressure over south central Canada with a ridge over much of our area.
247 PM MDT Wed Aug 25 2021 An upper trough is crossing the western CONUS, with WSW flow ahead of it moving into the Dakotas.
The upper-level ridge will shift east, but not enough (yet) to have any meaningful effect on our weather. The slight drop in afternoon high temperatures, along with (slight) continued drying of the lower atmosphere, should bring heat indices back down below advisory levels for tomorrow.
315 PM CDT Wed Aug 25 2021 Hot and humid conditions will continue through the weekend, but afternoon high temperatures will be slightly lower in the upcoming days as an upper ridge shifts east of the area.
Synoptically, there is limited support aloft, with the broad 500mb ridge axis still focused over the region, several weak short waves crossing NE/IA may provide some support. Highs will likely only push the lower 90s and heat index values will only reach the upper 90s. For the KC metro and locations to the south, heat index values are tempered as well, but still expected in the lower 100s.
Tranquil weather conditions across the Tennessee Valley this morning, with high pressure still promoting clear and calm conditions. Southwesterly flow will pick up this afternoon as the aforementioned ridge shifts east, allowing for the reinforcement of an already warm and humid air mass. Otherwise, we can expect yet another hot and humid day with highs in the low to mid 90s and heat index values peaking between 100 to 105 degrees. High pressure will allow another night of mostly clear skies and calm winds, with patchy fog possible again early Thursday morning. The upper ridge will weaken slightly and drift north-eastward across the Mid Mississippi Valley on Thursday, while a trough tries to build a little northward from the Gulf.
While precip chances for today are confined to mostly the Cumberland Plateau, tomorrow should see storms develop further west as the high located off the Carolina coast meanders westward and pushes a boundary through the midstate.
205 PM EDT Wed Aug 25 2021 High pressure will continue to build over the area through the end of the week. A large area of high pressure is located over the region this morning. The other over the higher terrain well WNW of the Richmond. Thunderstorms are expected to form over the Blue Ridge Mountains later this afternoon. though would not rule out an ISOLD stm both afternoons/early evenings INVOF a sea breeze or near the lee trough INVOF the higher terrain over the wrn half of VA.
1240 PM CDT Wed Aug 25 2021 After some morning isolated convection, ridging will allow for the hot and dry conditions to continue through the short term.
Otherwise, there no no concerns and VFR conditions will prevail as moisture is limited in the low levels of the atmosphere.
The low level jet will nose into the NE/SD/Southern MN area Thu afternoon, up to that outflow boundary and coincident with the right entrance region of an upper jet.
The 500 mb ridge does weaken just a bit, so maybe this is the reason for the uptick in convection. The forecast slight chance pop will continue, with the highest pops in the Pennyrile region of west KY.
The mean Westerlies remain well north of the forecast area with an anticyclone in control over the southern Plains. The forecast area resides on the northern periphery of this dome of high pressure. A Pacific trough is currently noted to be translating onshore over the Pacific northwest region.
"Cooler". Early afternoon temperatures were already in the lower to middle 90s with heat index values between 100-105. Persistence forecast for Thursday as the mid level ridge remains in place across the area.
211 PM EDT Wed Aug 25 2021 A combination of high pressure ridging over the southeast U.
It should better spawn thunderstorms across southeast OH if it makes its expected eastward progression, with the low potential for those storms to become severe with damaging wind the primary threat given high DCAPE values (related to dry air aloft) in the region.
Models shift better chances north and west tomorrow afternoon as the main upper trough axis shifts northwestward. Models continue to show broad swath of moisture over the eastern CONUS around the periphery of Bermuda ridge.
Highs on Thursday will be in the lower to middle 90s. An upper ridge begins to build into the Mid-Atlantic coast at the beginning of the period, then retrogrades to the west.
Early afternoon temperatures were already in the lower to middle 90s with heat index values between 100-105. Persistence forecast for Thursday as the mid level ridge remains in place across the area.
A cold front has pushed through the region today switching winds around to the northwest gusting at times to near 20 mph. RH values have dropped into the lower 30s leading to Near Critical Fire Weather conditions for the Arrowhead. Moving into Thursday the aforementioned cold front begins to lift northward as a warm front becoming quasi-stationary around northeastern NE to northern IA to southern WI. Additionally, a trough over the PAC NW will slowly move eastward which will put the CWA in southwest flow aloft. 5" along with strong theta-e advection will provide enough moisture for elevated showers to develop north of the warm front in an isentropic lift set-up.
Weak mean cloud layer flow (generally < 10kts) suggests some propagation out of the higher terrain is possible today, perhaps enhanced along any outflow boundaries that intrude through the valley amongst a very unstable airmass later in the afternoon/evening. Thus, did favor chance pops for the higher elevations, slight chances in the valley. As for Thursday, much the same as today however with slightly more shra/tsra coverage as the upper ridge weakens favoring gradual height falls and thus less inhibition. That being said, temperatures look to be a few degrees cooler (still above normal with heat indices nearing 100) given earlier cu formation, which could delay CI a bit, as well as reduce peak diurnal instability.
Another very hot and humid afternoon across the Tennessee Valley region again this afternoon, with temperatures in the low to mid 90s in most locations.
Temperatures should fall into the lower seventies tonight with the highest values in urban areas. Upper ridging moves further into the area on Thursday. The ridge over the area may also help limit any convection, and triggers for showers/storms may be limited until later in the afternoon, with some guidance indicating best chance for any rainfall may be further west across the upstate late in the day.
Otherwise dry but muggy conditions for the overnight with lows in the lower 70s.
Upper high will continue to dominate the overall weather pattern into the day Thursday with mostly clear skies and light east/ southeast winds. /Issued 315 PM CDT Wed Aug 25 2021/ Hot and humid conditions will continue through the weekend, but afternoon high temperatures will be slightly lower in the upcoming days as an upper ridge shifts east of the area.
A weak upper-level trough continues moving east across NRN CA early today. As that feature departs east, midlevel heights will rise slightly, and a warmer airmass will gradually develop across the WRN CONUS during the remainder of the week.
950 PM EDT Wed Aug 25 2021 A TUTT low is centered over the FL straits with a mid level trough extending from the SW Atlc into the NW Caribbean.
515 PM MDT Wed Aug 25 2021 An upper trough is crossing the western CONUS, with WSW flow ahead of it moving into the Dakotas.
This shower activity is being caused by a combination of a tropical wave bringing in moisture and a mid/upper level trough moving in combination with the wave. As the tropical wave and the mid/upper level trough continue to trek across our area overnight, widespread shower activity will continue, so have retained 60% PoPs.
Temperatures have fallen into the upper 80s to low 90s with heat indices just a few degrees warmer. Highs on Thursday will be in the lower to middle 90s. An upper ridge begins to build into the Mid-Atlantic coast at the beginning of the period, then retrogrades to the west.
626 PM CDT Wed Aug 25 2021 Upper trough is currently swinging across the Pacific Northwest with a broad area of upper ridging from the Ozarks through the southern High Plains. At the surface, cold front extends from far northeast KS to north of KDDC and is nearly stationary or lifting slowly north. The exception will be southeast KS which will hold dewpoints in the low 70s. Unfortunately this wave is not expected to push the cold front far enough south to make it into our forecast area. Subtle mid-level thermal trof across east central Kansas early Thursday morning and waning/modest low level jet may support AC/ACCAS over a portion of the Flint Hills and southeast Kansas.
205 PM PDT Wed Aug 25 2021 High pressure to the east will continue the warm trend through the weekend.
FEW-BKN mid and high clouds through the period as an upper trough sweeps across the region.
An upper trough is crossing the western CONUS, with WSW flow ahead of it moving into the Dakotas.
Activity once again likely to pick up through the day tomorrow as a westerly moving inverted trough and associated energy slides through.
Another hot day in store tomorrow with mid/upper level ridge over us. Upper high will continue to dominate the overall weather pattern into the day Thursday with mostly clear skies and light east/ southeast winds. /Issued 315 PM CDT Wed Aug 25 2021/ Hot and humid conditions will continue through the weekend, but afternoon high temperatures will be slightly lower in the upcoming days as an upper ridge shifts east of the area.
This will push us close to needing to extend the advisory into Friday, but at this point will let the next shift see if guidance trends any warmer.
Dewpoints should be lower than previous days, but some areas could still get close to advisory criteria, especially the Highway 81 corridor and parts of northern Kansas.
A weak mid-level trough will continue to progress westward across the area Thursday into Friday while also gradually dissipating. At the sfc, high pressure will continue from the western Atlantic into the southeast states. Plenty of deep layer moisture combined with daytime heating and the presence of the mid-level trough will lead to scattered to numerous showers and thunderstorms developing each day. High temperatures will generally be in the low 90s depending on when a site receives rain. Lows will remain very muggy, in the low 70s inland to mid 70s along the coast.
1136 PM CDT Wed Aug 25 2021 Upper trough is currently swinging across the Pacific Northwest with a broad area of upper ridging from the Ozarks through the southern High Plains. At the surface, cold front extends from far northeast KS to north of KDDC and is nearly stationary or lifting slowly north. The exception will be southeast KS which will hold dewpoints in the low 70s. Unfortunately this wave is not expected to push the cold front far enough south to make it into our forecast area. Otherwise the warm front will lift north later tonight with brisk southerly flow across central Kansas on Thursday. Some moisture within the subtle mid-level thermal trof across east central Kansas Thursday morning on the waning/modest low level jet may support AC/ACCAS over a portion of the Flint Hills and southeast Kansas.
Near normal temperatures, though slightly "cooler" highs on Friday along with seasonally elevated afternoon heat index values are expected.
JB Chattanooga Airport, TN 90 71 91 71 91 / 40 20 20 10 30 Knoxville McGhee Tyson Airport, TN 92 71 91 71 91 / 50 20 20 10 20 Oak Ridge, TN 91 70 91 70 90 / 40 20 30 10 20 Tri Cities Airport, TN 91 67 90 67 92 / 60 20 20 10 20.
The low level convergence axis will be confined to areas north and northwest of our southwest Kansas region, thus any late afternoon/evening thunderstorm activity will be in the region(s) north of our area. Friday will be a similar day with continued breezy south winds as the leeside trough/low pressure area will remain fixed across eastern Colorado into the Nebraska Panhandle. The lack of any appreciable convergence in the low level wind field will most likely prevent thunderstorm activity, so both today and Friday's forecast will remain dry.
Heat indices are forecast to peak around 100 degrees throughout the Lower Susquehanna Valley Thursday and Friday.
Synoptically, there is limited support aloft, with the broad 500mb ridge axis still focused over the region, several weak short waves crossing NE/IA may provide some support. Highs will likely only push the lower 90s and heat index values will only reach the upper 90s. For the KC metro and locations to the south, heat index values are tempered as well, but still expected in the lower 100s. The ridge will begin to break down and shift east with the push of a western trough on Friday.
An 80-knot jet will rotate around this trough will combine with instability to generate ample lift for scattered to widespread shower and thunderstorm development on Thursday. A midlevel trough will swing across the Northern Rockies on Friday with its base extending to our southern borders that afternoon. However, as the better support will be centered to our north and with weak west-southwest flow aloft, we will primarily see increased mid and high level clouds passing overhead with isolated to scattered convection developing over the higher terrain of the San Juans. This will be the area most favored for activity as a weak pulse of subtropical moisture interacts with the trough's base.
The 500 mb ridge does weaken just a bit, so maybe this is the reason for the uptick in convection. The forecast slight chance pop will continue, with the highest pops in the Pennyrile region of west KY. High pressure aloft and the surface, centered over the mid-Atlantic coast, will ridge over the Quad State this weekend.
Best chances will be in the southeast, with the lowest in the northwest during the peak heating of the day and then begin to decrease in coverage close to sunset.
224 AM MDT Thu Aug 26 2021 Southwest flow aloft will prevail over the region today as an upper trough approaches the area from the west. The upper trough moves into the area on Friday with widespread showers along with some thunderstorms especially in the afternoon.
Tomorrow, the forecast remains on track with scattered showers and thunderstorms expected once again with the highest chances of rain currently along and north of the I-20 corridor. Models shift better chances north and west tomorrow afternoon as the main upper trough axis shifts northwestward. Models continue to show broad swath of moisture over the eastern CONUS around the periphery of Bermuda ridge.
Latest satellite imagery and model analyses shows a mid-upper level trough now moving across the area. That said, all models show better agreement in the final solution for the aforementioned trough, which is expected to move into the Gulf later today, with rain chances diminish from east to west. Despite the increased cloud cover, temperatures should remain on the warm side during the short term with most areas reaching the lower 90s in the afternoon.
314 AM CDT Thu Aug 26 2021 Water vapor satellite loop this morning shows upper high pressure centered over eastern Kansas at 0730Z while a trough was moving eastward across the Pacific Northwest. Temperatures at 07Z were in the upper 70s to around 80 degrees with dewpoints in the lower 70s. Today the upper high remains over eastern Kansas with another day of hot temperatures and heat indices in the 102 to 107 degree range this afternoon. On Friday the upper high moves gradually eastward as the upper trough moves into the northern PLains. Slightly lower heights are expected over eastern Kansas, but highs will only be a few degrees cooler with mid to upper 90s common.
Heat indices are forecast to peak around 100 degrees throughout the Lower Susquehanna Valley today and Friday.
The latest surface analysis shows high pressure over south central Canada with a ridge over much of our area. The period begins on Friday with an upper level trough moving into the Northern Rockies, with southwesterly flow over the CWA.
Weak upper troughiness over the region to shift farther to our NW today, as an upper high centered offshore builds west some into our FA. On Friday, the upper ridge will be centered just northeast of the forecast area. As for temperatures, highs each day will be in the upper 80s to low 90s, with overnight lows in the lower to middle 70s.
Temperatures have fallen into the upper 80s to low 90s with heat indices just a few degrees warmer. Highs on Thursday will be in the lower to middle 90s.
302 AM CDT Thu Aug 26 2021 An upper trough located over the Pacific Northwest will begin to dig and erode a ridge that is parked over the Central and Southern Plains. The cold front that is associated with this system is expected to retreat northward as the ridge flexes its muscles over the state during the day today. By this evening the trough located over the Pacific Northwest should begin to slowly erode the ridge and the ridge begins to lose its influence over the area.
Deeper southeast flow will develop on Friday as an U/L ridge builds along the mid Atlantic coast and potential tropical development occurs over the western Caribbean which is expected to move toward the central Gulf of Mexico.
1121 PM MDT Wed Aug 25 2021 High pressure building off to the north over the northern Great Plains, with a stationary frontal boundary draped across southern Wyoming and the Rockie Mountains. Red Flag warnings remain in effect west of the Laramie Range with RH values in the low teens and some gusty winds behind the stationary frontal boundary across our southern region. A blocking high pattern that is likely to build across the southern portion of the CONUS in the coming days is expected to weaken by the early part of the weekend. Once this feature fully weakens and pushes eastward, an upper level trough will begin to dig east/southeastward from the Pacific Northwest towards the Rockie Mountains.
An upper trough will move through Thursday and Friday for precipitation chances and cooler weather.
The main player in the short term forecast will be mid-/upper-level high pressure positioned just off the NC/SC coast. Over the last 24 hours or so, a disturbance riding along the periphery of this high passed over the CWA from southeast to northwest. Models indicate another mid-/upper-level wave drifting northwestward around the high and across the CWA through the day Friday, bringing with it another surge of tropical moisture.
Tomorrow, the forecast remains on track with scattered showers and thunderstorms expected once again with the highest chances of rain currently along and north of the I-20 corridor. Models shift better chances north and west tomorrow afternoon as the main upper trough axis shifts northwestward. Models continue to show broad swath of moisture over the eastern CONUS around the periphery of Bermuda ridge. Mid-level to high clouds are scattered across north and central GA tonight, but starting to see patchy LIFR cigs develop where there are breaks in the higher clouds.
Mid level ridge retrogrades to Carolinas this weekend in deference to strong northern stream wave progressing eastward through southern Canada.
The upper level ridge that has been centered across the area will shift to the east during the period, weakening across Arkansas. This will allow the upper level flow to become more southeasterly as the ridge sets up across the mid-Atlantic seaboard.
Highs will remain in the low to mid 90s across the area with dew point temps in the low 70s.
(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.
The southeast ridge will creep slowly northward through the weekend in response to a trough dipping into the northern Great Plains. Drier and cooler conditions should develop eventually with a strong enough trough passage and attendant cold front.
VFR conditions will prevail beneath high pressure aloft. Another hot day in store tomorrow with mid/upper level ridge over us. Upper high will continue to dominate the overall weather pattern into the day Thursday with mostly clear skies and light east/ southeast winds. /Issued 315 PM CDT Wed Aug 25 2021/ Hot and humid conditions will continue through the weekend, but afternoon high temperatures will be slightly lower in the upcoming days as an upper ridge shifts east of the area.
Weak upper troughiness over the region to shift farther to our NW today, as an upper high centered offshore builds west some into our FA.
216 AM MDT Thu Aug 26 2021 Broad upper ridging covers the eastern 2/3 of the CONUS, while an upper trough is over the west coast. Some low ceilings may linger across northwestern/central SD through the day, and temperatures there are expected to be noticeably cooler (70s) than areas farther south (80s). As the main trough crosses the region, most of its energy will be to our north.
323 AM CDT Thu Aug 26 2021 Latest 07z surface analysis shows high pressure over northern Minnesota/northwest Wisconsin and boundary extending from central Wisconsin into central Iowa. the GFS/NAM indicate the nose of the low level jet/axis of stronger moisture transport to be over north central Iowa/south central Minnesota tonight. where the higher rainfall amounts are forecasted. 00z deterministic models indicate the higher chances for showers/storms will be over the northern sections of the forecast area. This would allow for the higher rainfall amounts over the northern forecast area.
Upper ridging breaks down today with a deeper easterly flow developing. This will bring a couple of changes to us; slightly cooler afternoon highs and even a few storms to portions of the area. Temperatures will come down a few degrees with most locations in the low to mid 90's this afternoon. The lower atmosphere is pretty dry so not sure much will make it to the ground.
908 PM PDT Wed Aug 25 2021 High pressure will build into Southern California the next several days, supporting above average temperatures through the weekend.
The low level jet will nose into the NE/SD/Southern MN area Thu afternoon, up to that outflow boundary and coincident with the right entrance region of an upper jet. We should remain in this unsettled pattern until a stronger wave and associated cold front moves through.
Other sub-severe showers and storms will also continue to develop further north and east along the nose of the low level jet. Storms will mainly move out of the area by late morning, giving way to a cloudy and cool afternoon with highs in the lower 60s to lower 70s.
Early afternoon temperatures were already in the lower to middle 90s with heat index values between 100-105. Persistence forecast for Thursday as the mid level ridge remains in place across the area. The upper level pattern begins to shift starting Friday with the upper ridge beginning to suppress to the south and east. Temperatures on Friday may be 2-4 degrees cooler however with ample sunshine and drying conditions, may not see much change versus previous days.