Aikyam-Lab/Synoptic-Bench huggingface dataset:
Rain chances will be non-zero but quite low through the weekend and the majority of the coming work week as ridging builds, pushing any subtle waves like today's a bit further to the east. Slightly better chances for precipitation and slightly cooler temperatures are possible by the end of the coming week, when longer-range models hint at a breakdown of the ridge ahead of a stronger trough that could move through the central CONUS in the 8-14 day outlook period.
459 AM EDT Fri Aug 21 2020 High pressure moving off the northern mid Atlantic coast will maintain dry weather to close the week, with temperatures trending above average into the weekend. Nearly stationary weak upper low over the central Gulf Coast states with an amplified upper ridge axis over the mid Atlantic states is directing thin cirrus over the southern 2/3 of PA this morning.
A weak ridge of high pressure will extend from the southern Great Lakes and OH Vly west to the Ozarks and southern Plains.
There is an upper level ridge over the desert southwest with northwesterly flow aloft across the central plains. Thunderstorms may form late this afternoon from the diurnal heating across the high plains.
SR Chattanooga Airport, TN 83 68 85 68 87 / 70 60 60 30 40 Knoxville McGhee Tyson Airport, TN 82 68 85 68 85 / 60 60 60 30 30 Oak Ridge, TN 82 67 85 66 85 / 60 50 60 30 40 Tri Cities Airport, TN 79 65 83 64 83 / 60 40 60 20 40.
151 AM EDT Fri Aug 21 2020 Scattered showers and thunderstorms are expected south of Pittsburgh Friday, and for the rest of the area over the weekend, with a crossing trough of low pressure.
Lows tonight will be much warmer than average due to cloud cover. Showers and thunderstorms will become more likely Saturday as a weak cold front approaches.
400 AM EDT Fri Aug 21 2020 High pressure will keep in dry and sunny weather for much of today and Saturday, with warming temperatures through the weekend.
Scattered showers and isolated thunderstorms return today south of Pittsburgh with warm, moist advection in increased southwesterly flow ahead of an approaching Midwestern/Mississippi Valley trough. Scattered shower and thunderstorm chances should expand north with continued diurnal instability and the aforementioned trough drifts northeast and temperatures aloft cool slightly.
/issued 236 PM CDT Thu Aug 20 2020/ Upper level high pressure remains to the west of the forecast area which will maintain northerly flow across the region today.
At the surface southerly flow should remain in tact through the night as a trough of low pressure develops to the west. CAPE values likely around 2000 J/kg but shear not very strong with the lowest km likely seeing stronger winds than the 1-10 km wind field. Upper level ridging gradually builds in from the west with upper level troughiness lagging into Saturday evening east of I-29.
331 AM CDT Fri Aug 21 2020 (Issued 330 AM CDT Fri Aug 21 2020) Today through Saturday: A near persistence forecast as high pressure exiting to the southeast slowly relinquishes control of our weather regime. Under a mainly sunny sky, temperatures will be a degree or two warmer than yesterday.
1043 PM CDT Thu Aug 20 2020 Message of the Day: The quiet weather continues with temperatures reaching the low 90s again by Saturday. The upper level high pressure remains out west, with a trough over the southern Mississippi River Valley. Winds have shifted to the south, which will allow temperatures to warm into the low to mid 80s, a couple degrees higher than yesterday.
108 AM EDT Fri Aug 21 2020 High pressure centered over northern Pennsylvania will continue to move slowly east and then off the New England Coast overnight. However a ridge of high pressure will persist across the region into the weekend.
This is thanks to a large scale upper trough being located over the Mid-South. However, expect at least isolated convection to continue through the overnight hours as an upper low pressure develops within the trough. The upper level low will slowly lift northward across the area through Saturday. Expect convection to blossom Friday afternoon over the Mid-South as the upper low interacts with daytime heating. By late Saturday afternoon, rain chances will begin to diminish as the upper low lifts off to the northeast.
This will do little to help combat the warmer temperatures, though will help to filter some drier air into western and north central Nebraska.
High pressure centered over Arizona will maintain a very warm airmass across the region through the upcoming weekend. Moisture rotating around this high will bring a threat for afternoon thunderstorms each day.
But we expect to see some recovery by early to mid afternoon allowing highs to return to near normal for late August with most areas seeing highs in the lower 90s. Seasonably cool low temperatures are anticipated once again with values bottoming out in the low to mid 60s for most areas. As we move through the weekend we expect to see an increasing influence from the mid/upper ridge with some subtle increase in thickness supporting slowly rising temperatures through the period. The mid/upper ridge is progged to slowly expand north and eastwards towards the area through the middle of the week.
334 AM EDT Fri Aug 21 2020 High pressure will keep fair weather and clear skies over New York and Pennsylvania through Saturday.
956 PM PDT Thu Aug 20 2020 The arrival of a vigorous cold front Friday afternoon will bring gusty winds to the Inland Northwest as well as rain to the Washington Cascades.
1112 PM EDT Thu Aug 20 2020 Water vapor imagery highlights an impressive mid-upper level trough across the Gulf of Mexico. The lift associated with this trough's eastern flank is well removed to the northwest of the Florida Keys. A small jet max is rounding the base this evening, so we will have to watch for any short wave undulations punching east into the subtropical ridge's real estate, which is entrenched across the Keys. The low-level ridging reaches west across the Straits of Florida. 8" PW) across the Cay Sal Bank and the Bahamas, and this air mass should advect our way overnight as the low-level ridge lifts north. A high pressure ridge will build westward across the Florida Peninsula and eastern Gulf of Mexico tonight through Saturday.
Large scale mid tropospheric pattern features a ridge centered over AZ, which extends up into MT, Alberta and Saskatchewan. A trough stretches from the Great Lakes region down to the western Gulf of Mexico. At the surface, high pressure was over the eastern US with low pressure out to our west. 2 pm temperatures locally were in the lower and mid 80s. Highs Saturday will be a few degrees warmer than those Friday at most locations in our area. The ridge to our southwest is forecast to expand into the central part of the Plains, and temperatures should turn warmer.
Strong upper ridge to remain centered over the SW CONUS, while a cut off upper low remains over the lower Mississippi Valley, providing our region with a SW upper flow. The air mass will not change much on Saturday, with the upper trough to the west weakening and lifting north some through the day. Lows at night will once again be around 70 or in the lower 70s.
Some convection is expected to top the ridge later tonight into Friday and potentially impact the north/east portion of the area tomorrow afternoon/evening. A better chance for more widespread shower and thunderstorm activity will come later Friday night (particularly the overnight time frame) as the low level jet strengthens across the region and we get much better moisture transport and deep layer moisture convergence. Showers and a few thunderstorms will likely be ongoing from late Friday night into early Saturday morning as a 500mb trough moves across northern Minnesota. This activity is expected to diminish from west to east by mid afternoon before a weak cold front pushes through the state, potentially sparking another round of showers and thunderstorms late Saturday evening.
1048 PM CDT Thu Aug 20 2020 Quiet conditions acrs the area this evening as the region remains beneath dry air on the backside of a low/trough aloft over the lower MS Valley.
342 AM CDT Fri Aug 21 2020 The forecast today and Saturday will be driven by an upper level trof of low pressure that will drift slowly north from MS/AL into the TN and OH Valley regions by Saturday afternoon. closest to the nw periphery of the upper low.
Surface analysis reveals broad high pressure sprawled out across much of the Northeast CONUS and Ohio Valley. A few showers and storms have managed to pop up in some of the higher terrain in Tennessee and Kentucky. A broad upper level low over the Gulf Coast states will slowly lift north- northeastward toward our region tomorrow. While individual convective activity will be short-lived and pulse-like given the low environmental shear, there will be some potential for storms to reform along boundaries and result in some training. Friday night and Saturday look fairly unsettled with the upper low opening up as it lifts from the Deep South toward the upper Ohio Valley.
1043 PM CDT Thu Aug 20 2020 Temperatures once again have topped out in the low to mid 80s today, with dew points in the 50s. Friday will continue the dry spell but will be 2-4 degrees warmer than today. VFR conditions will persist through this TAF period as a mid- level ridge remains anchored over the Ozarks. Surface winds will be light and variable with high pressure in place.
301 AM CDT Fri Aug 21 2020 06Z surface data has high pressure over the Great Lakes. The northwest flow on the edge of the upper level ridge and dome of hot air over the southwest U.
149 AM EDT Fri Aug 21 2020 Scattered showers and thunderstorms are expected south of Pittsburgh Friday, and for the rest of the area over the weekend, with a crossing trough of low pressure.
The story continues to be a ridge in the west, zonal flow along the US-Canada border, and a ridge off the southeast US coast. Thereafter, the western ridge wobbles eastward as a trough dives in over British Columbia, expanding 90-degree heat further into our area.
Upper trough over eastern portions of the mid south will move little during this period.
Weak upper level trough will start to swing through overnight.
Current water vapor imagery shows a rather well-formed low pressure system along the Gulf Coast this morning. Activity from today should lessen overnight, but as the upper level system over the region continues to lift northward, the main trough axis will likely be overhead during the day tomorrow.
1151 PM CDT Thu Aug 20 2020 Late this afternoon, an upper level disturbance will move from Wyoming into Nebraska along a ridging pattern that is centered over the Four Corners. At the surface, a trough extends from North Dakota into Western Nebraska and the Front Range. Temperatures will be in the low to mid 90s and surface winds will be between 5 and 10 miles per hour. The upper level ridge currently over the Southwest U.
As the low-level jet ramps up, this should lead to the development of a few scattered showers and storms over southern Minnesota/northern Iowa. The heat and humidity returns for Friday as southerly winds continue to pull in warmer temperatures and more moisture. Another trough will approach later Saturday into Saturday evening with an associated surface boundary.
Low temperatures tonight will be in the 70s inland and in the low 80s along the coastal regions. With the upper level trough still lingering over the Lower MS Valley, a very similar weather pattern is to be expected Friday.
Northerly flow aloft will be maintained over the region as ridging remains to our west. Most locations will see highs above 100 today with advisory level conditions likely in the higher terrain and in the Big Bend.
Another mostly quiet late summer is underway thanks to high pressure centered over the Mid-Mississippi River Valley. Isolated showers are trying to push northwest into the far southeast Pennyrile as a trof axis moves towards Middle TN from the Gulf Coast. POPs increase Friday through Saturday as the trof axis lifts northward from the Gulf Coast and into the Ohio Valley. The highest POPs will be located over the southeast half of the CWA (MO Bootheel, far southern IL, western KY and southwest Indiana). Lows tonight will be a bit warmer than this morning's values, in the lower to middle 60s. High temperatures Friday and Saturday will reach the lower to middle 80s, with the higher values in our west/northwest where POPs and cloud cover will be less.
A strong upper ridge remains in place over the southwestern US with a trough over the southern Mississippi River Valley. This light southerly flow may enable a minor increase in moisture with slightly warmer temperatures this afternoon compared to the previous few days. Through the weekend, the upper ridge flattens out some but expands eastward in the process.
Inverted trough extends from eastern Kentucky into West Virginia early this evening. Moisture return from the Gulf advects into the Ohio River Valley ahead of an upper-level low, which will begin to interact with PVA from an upper trough. Highs will stay below normal generally in the lower 80s.
/issued 815 PM EDT Thu Aug 20 2020/ Early evening water vapor satellite imagery is showing a potent upper level trough over the northern Gulf coast, with deep moisture streaming across the Gulf of Mexico and into the Florida Peninsula.
Weak upper trough and plenty of moisture will result in scattered to numerous showers and storms developing Friday, possibly even before sunrise at CSV.
708 AM EDT Fri Aug 21 2020 High pressure moving off the northern mid Atlantic coast will maintain dry weather to close the week, with temperatures trending above average into the weekend. Nearly stationary weak upper low over the central Gulf Coast states with an amplified upper ridge axis over the mid Atlantic states wl continue to direct thin cirrus over the Commonwealth today.
06Z surface data has high pressure over the Great Lakes. The northwest flow on the edge of the upper level ridge and dome of hot air over the southwest U.
A persistent upper low will remain situated to the west of the forecast area through the day today. On Saturday, the upper low will begin migrating northeastward as the Bermuda high starts to build westward.
High pressure entered over Arizona will maintain a very warm airmass across the region through the upcoming weekend. Moisture rotating around this high will bring a threat for afternoon thunderstorms each day.
Forecast Summary: A few thunderstorms will remain possible through Saturday mainly in northeast Nebraska and west central Iowa around periphery of building upper level ridge.
SHORT TERM (Today through Saturday):South Texas remains between a large hot high pressure ridge to the west and a deep upper trough over the Lower Mississippi Valley.
An upper level low spinning across southeast Louisiana through central Mississippi will stream SCT to BKN high clouds across the region through the day with SCT fair weather CU developing during the afternoon. Similar to yesterday, small rain chances remain for late afternoon today, primarily over the Atchafalaya Basin in better proximity to the low aloft. Saturday looks like a return of more seasonal rain chances as the trof continues to lift newd, leaving behind a weakness aloft.
Today Through Saturday Night Upper lvl trof/shear axis rmns situated just to the E of the FA this mrng. Predawn temps were mainly in the 60s to the lower 70s. This wl keep AR under the influence of the aforementioned upr trof to our E, and the persistent strong upr ridge ovr the Wrn States. Diurnal convection wl be primarily be confined to the Ern part of the FA, where an axis of higher PW values and weak instability wl be situated in close proximity to the trof. Areal coverage wl be somewhat less on Sat vs today as the trof weakens and shifts a bit further Ewd.
/issued 321 AM CDT Fri Aug 21 2020/ Weak cyclonic flow at the surface and a highly amplified mid level trough centered just East of the Mississippi River Valley is helping to maintain an area of showers and thunderstorms on the East side of the trough over North Mississippi. As storms approach the Mississippi River/trough axis they should move into a less supportive environment and weaken. Over the next 24 hours or so the Trough will remain nearly stationary then broaden and shift slightly farther East tonight into Early Saturday. More cloud cover today may keep temperatures slightly cooler than yesterday.
Due to the cloud cover and precipitation chances across this area, expect the higher temperatures today to generally be across the northwestern half of the region. Tonight the H5 low will slowly open up and the trof will start to lift up. Low temperatures will range from the lower 60s in the far northwest to the mid 60s in the Scioto Valley and southern counties. On Saturday the ejecting H5 trof will lift into the Ohio Valley. Highs will range in the lower to mid 80s on Saturday, with the warmer temperatures possibly in the north, Deep moisture remains Saturday night as a weakening trough sits over the Ohio Valley.
640 AM EDT Fri Aug 21 2020 High pressure will keep in dry and sunny weather for much of today and Saturday, with warming temperatures through the weekend.
Any showers or thunderstorms should remain well offshore east of the Lower Texas coast. /issued 418 AM CDT Fri Aug 21 2020/ SHORT TERM (Today through Saturday):South Texas remains between a large hot high pressure ridge to the west and a deep upper trough over the Lower Mississippi Valley.
542 AM MDT Fri Aug 21 2020 A combination of outflow from storms across NW SD and a cold front has produced gusty northwest winds across portions of the area this morning.
An Excessive Heat Warning continues for the lower elevations of the Grand Canyon and Glen Canyon through Friday evening.
Support for lift will be provided by a trough approaching the Ohio Vally and right entrance region jet support. Scattered shower and thunderstorm chances should expand north with continued diurnal instability and the aforementioned trough drifts northeast and temperatures aloft cool slightly. Scattered shower and thunderstorm chances should expand north with continued diurnal instability and the aforementioned trough drifts northeast and temperatures aloft cool slightly.
Similar to yesterday, small rain chances remain for late afternoon today, primarily over the Atchafalaya Basin in better proximity to the low aloft. Saturday looks like a return of more seasonal rain chances as the trof continues to lift newd, leaving behind a weakness aloft.
But this amplification of high pressure will be brief as a dry cold front is forecast to clip the Northern Rockies on Saturday. Widespread breeziness is expected with the front and this, plus cooler air behind the weak front, will lead to near normal temperatures.
The forecast today and Saturday will be driven by an upper level trof of low pressure that will drift slowly north from MS/AL into the TN and OH Valley regions by Saturday afternoon. closest to the nw periphery of the upper low.
549 AM CDT Fri Aug 21 2020 (Today through Saturday) Moderate to strong northerly flow will continue for a few more days, with gradient of upper high over intermountain region and upper trough/upper low across the lower and mid-MS valley region. Before the mentioned upper low gets kicked northeast over the weekend, the northerly flow will allow a weak s/wv trough to progress out of the central plains and over Oklahoma/northern Texas late today through early Saturday.
H85 temps continue to creep up, and thus highs will be a few degrees warmer than yesterday, with most areas returning to the low 90s. The Ozarks will stay a little cooler as usual, in the upper 80s.
123 PM PDT Fri Aug 21 2020 Hot weather will continue today, except at the coast and in the higher elevations.
12Z upper air analysis shows a well defined upper trough from the TN River Valley to the central Gulf. Embedded in the trough axis, forecasters find a cyclonic gyre spinning in place over the southern half of MS. The upper trough remains in a nearly fixed position tonight and Saturday with the upper level low lifting more to the northeast over the OH River Valley where it also fills/weakens by Saturday afternoon.
Highs will be above average in the lower to mid 90s. This means we will continue to remain in north and northwesterly flow aloft (till about Mon) and the primary concern is the potential for ridge runners.
Best PoPs lie along the southeast ridges where low-level convergence will also come into play. Upper troughing will continue to linger over the Ohio Valley through this period.
247 PM CDT Fri Aug 21 2020 Temperatures continue to rise into the lower 90s this afternoon, once again challenging forecast highs. Any multicellular development should track along the edge of the +10C 700 mb isothermal, moving into western Minnesota and along the Buffalo Ridge late in the evening.
113 PM EDT Fri Aug 21 2020 Ridge of high pressure will remain over the region into Saturday.
An Excessive Heat Warning continues for the lower elevations of the Grand Canyon and Glen Canyon through this evening.
An upper level trough dominating the region will begin to lift to the northeast this weekend. At the same time, a broad ridge axis will begin to extend eastward across the eastern Gulf of Mexico. A mid-level dry slot will continue to wrap around the base of the trough across the Gulf South tonight into tomorrow, and this will keep precipitable water values on the lower end at 1.
Aloft, stout upper ridge continued to reign acrs the southwest CONUS and up the Rockies, with northwest upper flow spilling down to the lee of it acrs the northern plains and upper MS RVR Valley.
Northerly to northwesterly flow is expected to reside over the forecast area through at least mid-week as a strong upper ridge remains in place over the southwestern US.
1055 AM CDT Fri Aug 21 2020 An upper level low is centered over MS this morning. /issued 321 AM CDT Fri Aug 21 2020/ Weak cyclonic flow at the surface and a highly amplified mid level trough centered just East of the Mississippi River Valley is helping to maintain an area of showers and thunderstorms on the East side of the trough over North Mississippi. As storms approach the Mississippi River/trough axis they should move into a less supportive environment and weaken. Over the next 24 hours or so the Trough will remain nearly stationary then broaden and shift slightly farther East tonight into Early Saturday. More cloud cover today may keep temperatures slightly cooler than yesterday.
An upper level low is situated over MS this afternoon. Overnight the upper low will track into Middle TN with chances for showers and thunderstorms continuing mainly along the TN River in West TN. The upper low will weaken over Middle TN and maybe inch a little east. Temps will range from the lower 80s east to upper 80s across parts of eastern AR.
332 PM EDT Fri Aug 21 2020 Ridge of high pressure will remain over the region into Saturday.
Otherwise, expect morning low temperatures to again be in the low to mid 60s with more seasonable temperatures over the weekend with near zero chances for any measurable precipitation as well. Chances for precipitation look to be slim to none through the end of the work week staying dry even not seeing any thunderstorms make it across from Colorado as the monsoonal trough looks to be on its downward trend off the foothills of the Rockies along the I-25 corridor. Morning low temperatures will be in the low to mid 60s with afternoon highs in the low to mid 90s, with warmer readings westward toward the Colorado state line. A cold front will push through suppressing the heat Friday with winds turning more north to northeasterly as well.
252 PM MDT Fri Aug 21 2020 Short term weather forecast will be dominated by the ridge to the south and the continued influx of smoke from the fires in California. The H5 ridge remains anchored on the UT/AZ border, and will wobble only slightly through the next 36 hours. Models are picking up on a weak vort trying to wrap through the state during the day tomorrow trying to spark a few showers for the highest elevations of the Wind and Absarokas, but the smoky atmosphere is strongly stabilizing the atmosphere, keeping convection to a minimum.