Aikyam-Lab/Synoptic-Bench huggingface dataset:
233 PM MDT Fri Aug 20 2021 Satellite imagery shows dynamic trough axis over eastern Montana slowly shifting to the east/northeast. Most of the precipitation and brisk northwest wind will diminish through the evening as a short wave ridge of high pressure develops over our region in the troughs wake. For Saturday, another trough drops down through Idaho and is set to track over our region late Saturday through Saturday night.
/Bouts of showers and storms continue, alongside a flood risk/ In general the H5 pattern today and Saturday is comparable, featuring a ridge axis centered toward our west with a trough axis focused toward our northeast.
1229 PM CDT Fri Aug 20 2021 (Today and tonight) Most of the models are showing a drier forecast across West Central Texas, as the upper level ridge to the east builds westward into the area. GFS still shows a little more convection along the western and northwest border of the area late this afternoon and evening along the periphery of the ridge. Will continue the idea of isolated convection across the western Concho Valley and western Big Country for one more day before the ridge can completely build into the area. Otherwise, temperatures a little warmer than yesterday with highs mainly in the mid 90s.
Still expecting most of the thunderstorm activity to shift out of our west central MN counties by around 00Z along with the cold front.
The closed low pressure that brought the active weather is lifting out over the northern plains today. Lows tonight will be warmer than this morning and skies will be mostly clear. Tomorrow the next trough tracks over the Pacific Northwest and northern Great Basin. Although the better chances reside across the northern third of the CWA closer to the lift associated with the trough passing to our north. The trough will clip us tomorrow night so the precipitation will generally be confined up north overnight.
A weak upper level low/trough will be situated to our northeast and east through the period, with high pressure/ridging aloft to our west. In the lower levels, features over the local area will be weak and amorphous, with a moist air mass in place.
A weak upper ridge will provide mostly clear (but smokey) skies and dry conditions today. Forecast was updated for thunderstorm coverage tonight through Saturday as an upper low moves through the region.
A surface cold front will drop southeast through the central Plains with an area of thunderstorms developing along this front this evening. Once the storms clear by later Saturday morning, most areas should be dry for the rest of the day as a weak cold front shifts south and east across most of the area.
1141 AM MDT Fri Aug 20 2021 The H5 trough is currently centered roughly over Thermopolis this morning, slowly drifting eastward. The trough will continue ejecting NE through the next 12 hours, Slowly drying the atmosphere in its wake. With the trough departing, the wraparound activity will be more showery in nature, with smaller areas getting any measurable precipitation. This will be brief, as the next trough drops southward into the Pacific Northwest.
Weak ridging aloft has resulted in dry conditions today across South Central Texas.
Looking at current conditions, temperatures this morning ended up being slightly warmer than forecast by about 1-2 degrees across the CWA.
Ridging aloft and a lack of convergent winds along the lake breeze from 925mb through 700mb will likely limit thunderstorm activity this afternoon. As the mid level trough approaches from the west it lifts northeast and takes on a negative tilt.
Storms are expected to develop along an associated cold front across Eastern Nebraska and Western Iowa this afternoon. After the passage of the cold front from Friday, we should see some brief relief from the heat with temperatures in the lower 80s across northern parts of the area, and mid 80s across the south. Unfortunately that won't last very long as high pressure and ridging starts to build over the southern and central Plains.
However, an impulse riding through the ridge position at 5h in MO and AR will combine with increasing west-northwest flow at 8h to increase convergence and moisture transport across the lower OH and TN valleys.
SHORT TERM (Tonight through Saturday Night ): High pressure over the northern Gulf at both the mid level and surface will lead to subsidence across the region through the short term with east to southeasterly flow. Overnight lows tonight and Saturday night will range from the upper 70s across the northern ranchlands to the lower 80s near the coast.
256 PM CDT Fri Aug 20 2021 A strong cold front is quickly tracking southeast across the forecast area this afternoon. this front has already passed southeast of the Tri-Cities resulting in cooler temperatures, less humidity, and breezy northwest winds. The cold front is expected to exit our southeastern counties around 6 pm this evening. Thunderstorms should form along this cold front between 5 and 7 pm and quickly develop into a broken line or line of storms primarily to the east of our forecast area.
A wedge-shaped deep, moist warm sector is in place off to the west across the eastern Plains and mid- Mississippi Valley ahead of a cold front. Temperatures are generally in the low to mid 80s, but relatively weak instability has kept the diurnal cu field in check. The cold front will push eastward over the Mississippi Valley tonight, and convection is likely to evolve southeastward from Missouri and Illinois across western KY and TN. Richer moisture ahead of the cold front tries to push into the western CWA Saturday afternoon.
While we will have elevated low- level moisture again tonight, the southerly flow, and approaching cloud cover associated with the cold front will likely keep widespread fog at bay. To our west this evening, a 500mb trough and some favorable 300mb jet dynamics will allow for thunderstorms to form along the cold front over Iowa and Minnesota. As the cold front and this line of storms moves eastward, some of the favorable upper lvl dynamics will lift north over Lake Superior, and these storms will likely weaken as they make their way into southern WI during the early morning hours. Highs tomorrow will be in the low 80 to mid 80s.
252 PM CDT Fri Aug 20 2021 An area of low pressure was located over the eastern Dakotas with an attendant cold front extending down into Nebraska and NW Kansas. A line of storms is expected to organize along a cold front over western Iowa this evening into the first part of tonight. Otherwise, expect decreasing humidity through the afternoon and highs in the low 80s northwest to mid/upper 80s elsewhere.
Isolated showers in Preston/Tucker county, prompted by trough over the ridges, will continue into the early evening. Dry conditions will likely stay near and to the west of Pittsburgh throughout the day tomorrow under high pressure. Temperature trends will remain at or slightly above average throughout this period under high pressure.
On Saturday, a cold front will be moving slowly south across the Panhandles.
There is a wide range in temperatures across the area early this afternoon, with areas that haven't received any rainfall in the lower 90s, but with many areas in the 80s and some areas that have seen the most rainfall even in the upper 70s. Otherwise, upper ridging continues over the southeastern states through Saturday, especially over the western half of the area. High temperatures will continue in the lower 90s outside of rain areas on Saturday, but cooler (upper 70s through 80s) in and near rain areas, and also vary during the afternoon as showers and storms come and go. Lows tonight in the low to mid 70s over inland areas, but upper 70s along the immediate coast.
123 PM EDT Fri Aug 20 2021 A broad upper level trough is expected to linger over the region through Saturday.
2) Warmer temperatures on Saturday with chances of scattered showers and thunderstorms focused across the southern Cumberland Plateau, and southern valley. H5 analysis places troughing from the Great Lakes and across the central/southern Appalachians. Tonight, an H5 impulse will move over the ridge centered over the Mississippi river and provide a focus for numerous showers and possibly embedded thunderstorms overnight across western and middle Tennessee. Highs on Saturday will be a couple degrees warmer with mid to upper 80's likely.
This afternoon through Saturday night The upper low is over northeast WY this morning and will track over the Northern Plains today. Gusty northwest winds will occur over the Wind Corridor, eastern portions of the Bighorn Basin and Johnson County, as a result of the low exiting the area. Precipitation amounts are not expected to be as high as this latest event, although the highest accumulations between 0.
The flow aloft will quickly turn back southwesterly tonight as the next upper trof drops into the Pacific Northwest region. Latest HRRR/NAM does show some of these showers developing later tonight and will leave the low chances already in the forecast.
A cold front will move into northern Missouri tonight. Temperatures will be seasonally warm tonight with lows Saturday morning in the low to mid 70s. As the cold front drops into southwest and central Missouri on Saturday, the chance for thunderstorms will increase across the region. As the cold front moves closer to the Mid-South from the north Saturday night, there will still be a chance of thunderstorms.
At 20Z, mid-level water vapor imagery shows the trough moving into the northern Plains. Brief backbuilding of storms could also cause concern for flash flooding as the cold front passes. The cold front will push through the area by Saturday morning ushering in dryer and cooler air.
A mid level s/wv ridge will extend from east TX to southern MO tonight. As additional mid level energy tops the ridge and moves southeast, more showers and storms will develop, after an evening lull.
A sprawling upper low will gradually shift its position over the region and subsequently interact with TS Henri over the next couple of days. A closed upper level low across the mid-Atlantic states on Saturday will interact with tropical system Henri over the weekend.
412 PM EDT Fri Aug 20 2021 The threat for showers and thunderstorms is forecast to be isolated today under this weak high pressure.
Isolated showers in Preston/Tucker county, prompted by trough over the ridges, will continue into the early evening. Otherwise, a mostly nice day north of Morgantown; stratocu should dissolve as mixing prevails in the low- levels. Dry conditions will likely stay near and to the west of Pittsburgh throughout the day tomorrow under high pressure. Temperature trends will remain at or slightly above average throughout this period under high pressure.
Current thinking is that despite the trough pulling away to the northeast, a stable layer right above mountain top height is allowing for mountain-wave-influenced winds at the surface. Dry weather is expected to start off the day on Saturday, however by afternoon our next trough will approach from the west. Some isolated showers are expected to develop off the higher terrain to the southwest and drift northeastward through the day.
High pressure will start to build in a bit stronger with deeper moisture returning through the weekend as the tropical systems continue to move away from the region. Light winds and seas will continue under high pressure through the period.
An area of low pressure was located over the eastern Dakotas with an attendant cold front extending down into Nebraska and NW Kansas. A line of storms is expected to organize along a cold front over western Iowa this evening into the first part of tonight. Otherwise, expect decreasing humidity through the afternoon and highs in the low 80s northwest to mid/upper 80s elsewhere.
Current obs with dewpoints in the mid 70s and even upper 70s west of the TN River suggest plenty of moisture with little needed to trigger showers and storms that will be very efficient rain producers thanks to high freezing levels near 15-16kft, PWATs over 2 inches, and MLCAPE around 1000 J/kg.
Saturday, a sprawling upper low will gradually shift its position over the region and subsequently interact with TS Henri over the next couple of days. A closed upper level low across the mid-Atlantic states will interact with tropical system Henri during this period. expect daytime highs to primarily range from the lower 80s across the higher terrain to the mid and possibly a few upper 80s across the lower elevations. while nighttime lows range from the low to mid 60s across the Southern Tier to right around 70 near the lakeshores.
Buoyancy was similar to this morning, although boundaries are scarce outside of any residuals from this afternoon's wet cloud line across the lower Keys.
This could be the prefrontal trough or a sudo dryline with higher dewpoints to the east. At 20Z, mid-level water vapor imagery shows the trough moving into the northern Plains. Brief backbuilding of storms could also cause concern for flash flooding as the cold front passes. The cold front will push through the area by Saturday morning ushering in dryer and cooler air.
Isolated showers in Preston/Tucker county, prompted by trough over the ridges, will continue into the evening. Dry conditions will likely stay near and to the west of Pittsburgh throughout the day tomorrow under high pressure. Temperature trends will remain at or slightly above average throughout this period under high pressure.
Temperatures remain in the 80s across most of the area with overnight lows expected in the low to middle 70s. Showers should decrease in coverage over the next few hours but may increase in coverage prior to sunrise as a weak trough moves across Missouri. Rain free areas may spike near 90 degrees while areas where rain is nearly continuous may remain in the low 80s. A cold front will move into northern Missouri tonight. Temperatures will be seasonally warm tonight with lows Saturday morning in the low to mid 70s. As the cold front drops into southwest and central Missouri on Saturday, the chance for thunderstorms will increase across the region. As the cold front moves closer to the Mid-South from the north Saturday night, there will still be a chance of thunderstorms.
714 PM EDT Fri Aug 20 2021 The threat for showers and thunderstorms is forecast to be isolated today under this weak high pressure.
628 PM MDT Fri Aug 20 2021 Southwest flow aloft persists over the Central High Plains today with an upper trough moving across the West River region of South Dakota this afternoon. A ridge remains to the east on Saturday with high pressure persisting over Texas and Louisiana. High temperatures this afternoon and tomorrow will range from the low to mid-80s.
946 PM EDT Fri Aug 20 2021 The threat for showers and thunderstorms is forecast to be isolated today under this weak high pressure.
706 PM CDT Fri Aug 20 2021 For the 00Z TAFs, a surface trof will slowly move southward across the region tonight into Saturday morning with winds becoming north to northeast. On Saturday, a cold front will be moving slowly south across the Panhandles.
Decided to allow the High Wind Warning to expire on time for WYZ 110. Current thinking is that despite the trough pulling away to the northeast, a stable layer right above mountain top height is allowing for mountain-wave-influenced winds at the surface. Dry weather is expected to start off the day on Saturday, however by afternoon our next trough will approach from the west. Some isolated showers are expected to develop off the higher terrain to the southwest and drift northeastward through the day.
305 PM MDT Fri Aug 20 2021 Expect cooler than normal temperatures across the region, today, with a few afternoon thunderstorms possible. An upper level trof currently located over eastern Montana continues northeastward out of the area. Continuing cloudy skies aid in keeping temperatures cooler than normal, with todayâs low elevation highs generally ranging in the 60s, across the region. Expect lingering rain showers to decrease during the evening and overnight hours under a brief, weak upper level ridge. Tomorrow morning, an upstream upper level trof begins to dominate The Treasure State.
310 PM MDT Fri Aug 20 2021 Southwest flow aloft persists over the Central High Plains today with an upper trough moving across the West River region of South Dakota this afternoon. A ridge remains to the east on Saturday with high pressure persisting over Texas and Louisiana. High temperatures this afternoon and tomorrow will range from the low to mid-80s.
A strong cold front is quickly tracking southeast across the forecast area this afternoon. this front has already passed southeast of the Tri-Cities resulting in cooler temperatures, less humidity, and breezy northwest winds. The cold front is expected to exit our southeastern counties around 6 pm this evening. Thunderstorms should form along this cold front between 5 and 7 pm and quickly develop into a broken line or line of storms primarily to the east of our forecast area.
Expect cooler than normal temperatures across the region, today, with a few afternoon thunderstorms possible. An upper level trof currently located over eastern Montana continues northeastward out of the area. Continuing cloudy skies aid in keeping temperatures cooler than normal, with todayâs low elevation highs generally ranging in the 60s, across the region. Expect lingering rain showers to decrease during the evening and overnight hours under a brief, weak upper level ridge. Tomorrow morning, an upstream upper level trof begins to dominate The Treasure State.
Northern Sacramento Valley is running anywhere from 6 to 11 deg F cooler compared to this time 24 hours ago, whereas the southern Sacramento and northern San Joaquin Valleys are running +/- 4 deg F from yesterday. Forecast highs for this afternoon range from the middle 80s to near 90 in the Delta to Sacramento City, up to the low/middle 90s in northern Sacramento Valley. Dry, northwest flow aloft remains overhead as an upper level low quickly ejects east from the Rockies.
250 AM MDT Sat Aug 21 2021 Current surface analysis shows cold front well south and east of the region, with weak high pressure over eastern MT into WY. Upper level analysis shows trough moving northeast into Canada. Some 30s are noted across the highest elevations of the Black Hills. Cooler conditions will continue today, with high temperatures in the 70s to around 80 degrees under mostly sunny skies. Most of the activity should move east of the forecast area by Sunday afternoon as the trough moves quickly east-northeast and a Pacific cool front pushes through. Breezy conditions will develop behind the frontal passage, with highs ranging from the 70s over the Black Hills to the lower 90s toward south central SD.
On Sun, and upper ridge finally builds, and holds largely into Tue night. Upper ridge does weaken mid-week and on Thu a weak frontal boundary sets up across the southern OH valley. This pattern will bring a good increase of shower/storm activity back to the area for late week, especially if a weak upper low forms over the deep south which a few models suggest.
A synoptic pattern chance is already underway with the subtropical ridge building over the Lower MS Valley. This ridge will become the dominant feature over the central CONUS by tomorrow, keeping the impressive cyclones near the US/Canadian border well to our north. The ridge will be the main player tomorrow through midweek, limiting rain chances and pushing temperatures into the mid 90s.
The Subtropical Ridge remains dominant over South Central Texas this weekend with a mostly subsident airmass.
329 AM EDT Sat Aug 21 2021 Tropical cyclone Henri will move north, well off the Atlantic coast today through Sunday.
Highs will be a little cooler with upper 70s to upper 80s across the area.
1224 AM CDT Sat Aug 21 2021 A strong cold front is quickly tracking southeast across the forecast area this afternoon. this front has already passed southeast of the Tri-Cities resulting in cooler temperatures, less humidity, and breezy northwest winds. The cold front is expected to exit our southeastern counties around 6 pm this evening. Thunderstorms should form along this cold front between 5 and 7 pm and quickly develop into a broken line or line of storms primarily to the east of our forecast area. The upper trough will bring with it stronger winds aloft to create favorable wind shear, while return southerly flow will allow for increasing low level moisture and increasing instability.
Not only will temperatures be cooler (afternoon highs near 80 degrees), but dewpoints will fall back into the upper 50s! Expect this to cut down on the muggyness and bring a crisper feeling to the northerly breezes today. Ahead of the trough our winds will become gusty from the south (gusts 25 to 30 mph in the afternoon), ushering moisture back into the region (PW values near 1. The highest severe risk is expected in northeast Nebraska, though storms could creep towards the Metros (Lincoln and Omaha) after sunset.
414 AM EDT Sat Aug 21 2021 Similar to yesterday, the CWA is situated between an upper trough over the Mid-Atlantic States and an upper ridge centered over TX and LA. A similar synoptic setup is on tap for Sunday, although the upper ridge will amplify a bit across the central U. and flatten the upper trough, pushing it further up the Eastern Seaboard.
A bowing cold front, currently dropping south along western Iowa and curving westward through the Oklahoma panhandle, is traveling slowly to the east. By Sunday morning, a very weak/diffuse cold front could be approaching northern portions of the region. A strong upper level ridge centered over the southern Plains and ArkLaTex region will then influence our weather through at least midweek. We start to see some changes in our weather by the late-week period as a cold front moves into the Midwest and a weak upper level wave with tropical origins drifts toward our region.
320 AM CDT Sat Aug 21 2021 A strong, negatively tilted trough was moving through the Northern Plains and Upper Midwest early this morning. Its associated cold front was pushing through the forecast area with the line of convection now slowly pushing south and east of the forecast area. A slightly cooler but noticeably drier air mass will settle over the area today.
Thunderstorms were ongoing across the southeast zones as of midnight on the cold side of a weak cold front that has pushed through our area into OK, and this activity will pose little threats outside of periodic heavy rain and lightning as it moves gradually eastward.
VFR expected for the rest of the package tomorrow with light winds continuing across the area where high pressure prevails. with high pressure in control. An upper level ridge that began to build into the region today limited activity this morning and this afternoon as well.
However, recently some showers did develop in the vicinity of the lower Keys and in fact a brief shower managed to move over the Key West Airport. This high pressure is slowly becoming absorbed by a ridge axis extending westward from the Bermuda High currently across the central North Atlantic. As this ridge axis continues to build in across the region, additional moisture will gradually filter into the area. In addition, due to the strengthening of the high, expect breezy conditions to develop.
A large area of upper level low pressure is over WV.
High pressure aloft wl gradually bld into the region fm the S, with far Nrn and Ern AR staying on the periphery of this feature. This wl keep convective chcs in the fcst thru much of the weekend, with the higher PoPs mentioned in the vcnty of the sfc bndry.
BW Chattanooga Airport, TN 86 71 90 71 93 / 40 30 40 10 10 Knoxville McGhee Tyson Airport, TN 89 70 90 70 92 / 10 20 30 10 10 Oak Ridge, TN 89 69 90 69 91 / 20 20 30 10 10 Tri Cities Airport, TN 86 64 88 65 90 / 10 10 20 10 10.