Aikyam-Lab/Synoptic-Bench huggingface dataset:
Heights continue to fall over northern Arizona today as a longwave trough continue to move eastward across the Great Basin and pass just to the north. Consequently, some surface gusts this afternoon, especially in the high terrain are expected to approach 30-35 mph. As the trough passes, much of the monsoonal moisture is sweep away resulting in a dry day today for much of the area. The exception being far northern Arizona near the Utah border where enhanced forcing from the trough and some remnant moisture will lead to scattered showers and thunderstorms this afternoon. In the wake of the trough, dry conditions are expected across much of northern Arizona Friday and into the weekend.
The closed low to the east of NorCal is presently centered near the NV/ID/UT border. Northerly wind gusts are currently mainly in the teens to low 20s mph along the western edge of the Sacramento Valley, while some local northeast gusts of 25-35 mph are present across the higher elevations of the northern Sierra and near southwest facing canyons in Butte County.
A cut off upper low will then drift southeast across the region late this week with unsettled conditions through the upcoming weekend. The remnants of tropical cyclone Fred continue to exit northeastward into upstate New York at 1330z. Based on expected cloud cover, have undercut NBM max temps just a bit, with forecast highs ranging from the mid 70s over the highest terrain of the Appalachians, to the mid 80s across the Lower Susq Valley. Upper level trough will still be over the area Friday and through the upcoming weekend, resulting in a daily chance for pop up showers or a few rumbles of thunder.
225 PM MDT Thu Aug 19 2021 Anomalous upper level low pressure centered over northern UT early this afternoon will move northeast over WY tonight with its major trough axis crossing eastern UT and western CO between midnight and early Friday morning. The atmosphere ahead of the trough is moderately unstable south of I-70. Short term high resolution models have handled the convection so far today pretty well and they show continued bands of showers/storms rolling northeast over the area through mid evening, before consolidating into one last band along the leading edge of the upper level trough and moving southeast of the area by Friday morning. Friday will be drier as precipitable water values drop to one half inch or less behind the trough. Temperatures will remain below normal under northwest flow aloft, but warmer than today with the abundant sunshine.
The weak upper level trough that has been the primary driver of weather the last few days is now over central Indiana, placing some relatively cool air aloft. With very light winds though the lowest 3km, these storms are not expected to move much, keeping the rain threat more local. For tomorrow, the trough should be well off to the east, leaving central Indiana in the same humid environment, but with no mid level lift apparent.
Dry conditions will continue for western Washington today as upper level ridging remains over the area.
High temperatures are expected to reach the lower 80s lower elevations to the 70s across higher elevations of the plateau and mountains of East Tennessee, southwest Virginia and southwest North Carolina.
/EC/ Tomorrow night through Thursday: The forecast period starts off tomorrow night with sub-tropical ridging building across the Lower Mississippi Valley while a closed low lingers over the Mid-Atlantic.
258 PM EDT Thu Aug 19 2021 High pressure remains centered over the southern lakes and northern OH Valley. With a humid airmass in place (dew points in the low-mid 60s), fog is again expected.
The first short wave trough lifting into the region from the southwest was showing shower and storm development into western Nebraska/western South Dakota this afternoon. Otherwise, the main upper level low pressure trough will make its way into and across the region Friday and Friday night. Therefore, expect storms to redevelop on Friday as the lift from this system moves in and a cold front sweeps quickly east. It will also be cooler on Friday with 70s and lower 80s for highs. With the upper level low/trough already well to our north, and southwesterly flow already by mid morning, expected limited additional chances for shower or thunderstorm activity.
With upper-level ridge forecast to build across the region on Friday, convection will be mainly confined to northeast Louisiana and southwest Arkansas.
Best forcing with this upper trough is expected to affect areas primarily along and south of US 30 later this afternoon/early evening. An anomalously deep upper level trof was digging into the Great Basin region early this morning.
Main concerns for this morning were with an unexpected cloud layer moving over the region as some upper level moisture moves across from the backside of the low in Utah. Beyond this, usual slight adjustments to temperatures occurred with some small 1-2 degree decreases as the morning clouds may help limit initial heating, along with some more medium term precipitation increases as the next trough moves into our region.
Showers or thunderstorms could last through most of the night, in an isolated state given the low level moisture and the development of a low level jet. Low level moisture will still be plentiful to the east of the trough so the instability may be there to produce a strong and possibly severe storm.
Most of South Central Texas is on the western periphery of a ridge aloft. Precipitable water values fall slightly over the region tomorrow and the ridge aloft noses slightly farther west into the area, contributing to mostly dry and warm conditions.
Isolated showers and thunderstorms are expected again tomorrow southeast of Pittsburgh as an upper trough closes over PA. However, Hi-Res model soundings note warm air in the low-levels that could disrupt updraft development.
The area of continued development will spread eastward through the afternoon and evening as the pattern shifts east and a short wave trough ahead of the main upper trough lifts out across the central High Plains region. A cold front moves through the area after midnight tonight with a few showers possibly lingering across the area into early Friday as the main upper trough moves across the central High Plain by mid-day Friday.
1224 PM CDT Thu Aug 19 2021 (18Z TAFS) TSRA is possible across much of the area, the highest confidence occurring around KFST this afternoon. (Today through Friday afternoon) Summer usually means a relatively stagnant weather pattern, and our pattern is settling into a typical summer pattern with high pressure dominating the southern United States. The main difference is the high is weaker than normal and thus temperatures are lower than we might normally expect. Low pressure over the West Coast will send a couple of disturbances across West Texas and eastern New Mexico causing afternoon showers and thunderstorms to develop in the mountains in the Big Bend that will drift northeast into the Trans Pecos and Permian Basin both today and tomorrow. The highest PoPs will be in the Davis Mountains with shower activity diminishing farther east as instability decreases.
Also H5 troughing is still present over srn Lwr MI and the Ohio Valley Region into New England. However ridging and drier air aloft will be leaning in from the west so the risk should be lower.
The threat for showers and thunderstorms is forecast to diminish Friday under weak high pressure. Main area of rain has moved east following a mid level trough axis and band of low level convergence. Though weak high pressure should provide dry weather for most locations, isolated showers may pop up Friday afternoon in a humid regime containing marginal instability. This will allow heights to rise, although there will be a short wave riding over the top of the building ridge which will pass across the Great Lakes.
Clouds associated with an upper low to our east will continue across portions of southwest Idaho.
Overnight lows look to reach the low to mid 70s. Surface dew points are progged to remain in the low to mid 70s with temperatures surging into the low to mid 90s ahead of the front.
The trough will begin to accelerate east-northeast across the region Friday into Friday night, with relatively better chances for additional rainfall coming across northeastern portions of the CWA.
A Compact area of deep layer ridging centered along the AL/GA/FL border shifts to the central/western Gulf coast and spills southward by Fri as Tropical Storm Henri moves north off the southeast US coast. With the deep layer ridging sagging out into the Gulf the 1000- 700MB flow goes from northeasterly to northerly and northwesterly. Sat through next Thu: Ridging aloft meanders over the western Gulf coast/lower Mississippi Valley as it sprawls across much of the Gulf region. Although a trough/low tracks toward FL and the east Gulf mid to late week. The approaching upper trough/low may result in an increase showers and storms toward the end of the week. High pressure north of the waters shifts out over the Gulf Fri then is reinforced from the east during the weekend. This high pressure lifts north early to mid week.
Tonight and Friday Quiet and more humid weather continues through the short-term portion of the forecast High pressure is expected to continue drifting gradually to the east through this time period; however, it will remain in control of the weather through Friday.
The trough that has been digging into the Great Basin to our north will slowly shift into the front range over the next 24 hours. Temps will climb as we dry and a ridge builds in from the east.
On Friday, the forecast area will be situated in a northwest flow regime aloft between the building ridge to the west and trough over the Northeast. While the impetus for development will be less clear cut than today, the combination of the moist airmass as well as any weak perturbations working around the periphery of the trough will allow for the development of scattered thunderstorms again by Friday afternoon. 5-2") lingers across the area until the fringes of the high begins to push it off towards the Gulf, so a diurnally-forced convective pattern will be maintained through the weekend.
Temperatures will remain on the warm side with lows Friday morning in the low to mid 70s.
The upper low is currently located over northern UT and will slowly move northeast over the Cowboy State through the overnight hours. The low is expected to be over eastern WY by 12Z Friday. Scattered rain showers will occur over areas east of the Divide, including the Absarokas and Yellowstone through the morning, and continue across the north through Friday afternoon as the upper low exits over the Northern Plains.
(This evening through Friday) Showers and thunderstorms have developed to the west of the area over the higher terrain of the west Texas mountains. Lows tonight will be warm and muggy, likely only falling into the low to mid 70s with the higher than normal amount of moisture in the area.
232 PM CDT Thu Aug 19 2021 High pressure remains in control with warm and humid conditions over the Upper Mississippi Valley.
Minimal support aloft today given the mid-level ridge and convergent portion of the upper jet atop a weakly sheared environment (EBS of 15 knots or less) hinder narrow showers/storms of the pulse variety. Eastern upper low will gyrate and retrograde Friday as the PV anomaly releases through the Ohio Valley, arcing toward the Mid- Atlantic. Forecast soundings depict a subsidence inversion near H7 given ambient isentropic downglide associated with regional anticyclone.
Upper low to our east will slowly lose impact over our area tonight.
The overnight period is expected to be rather warm and muggy, with overnight lows generally in the low-70s. This may allow afternoon highs to climb into the low-90s across the far western CWA.
(18Z TAFS) TSRA is possible across much of the area, the highest confidence occurring around KFST this afternoon. (This afternoon through Friday night) An upper lvl trough over Western CONUS will continue to progress eastward into this weekend. Therefore, thunderstorms are likely this afternoon as result of daytime heating, orographic ascent (over the mountain areas), and the progression of the aforementioned trough. Temperatures will sit in the low 90s this afternoon and tomorrow afternoon with upper 90s to 100s along the Rio Grande.
A weak ridge extends across the North Atlantic, interrupted by Tropical Storm Grace in the vicinity of the Yucatan Peninsula as well as Tropical Storm Henri west of Bermuda.
Deep ridge across the area will keep convection scattered this evening with the best chances over the interior. The mid-upper ridge starts to shift to the west late Friday as a trough digs south near the east coast.
Currently, an upper level ridge over the northern Gulf coast continues to shift west, eventually building north along the Mississippi River Friday as an upper level low over the northeastern Conus shifts south. Low temperatures in the low to mid 70s inland, mid to upper 70s along the coast. The highest chance of any strong to marginally severe storms shifts to over our coastal counties, with the best daytime heating and instability.
A couple lightning strikes have been observed, but the tropical atmosphere still remains with a high freezing level near 14kft.
915 PM EDT Thu Aug 19 2021 A cut off upper low will drift southeast across the region for the next few days with unsettled and occasionally showery conditions lasting through the upcoming weekend. Lows by daybreak should range from around 60 in the northern mountains, to near 70 in parts of the Lower Susquehanna Valley. Temperatures will be similar to Thursday and generally range from the upper 70s to the lower 80s throughout.
940 PM EDT Thu Aug 19 2021 An upper level low will head eastward from the Great Lakes tonight, which will bring more showers and thunderstorms on Friday. An upper level trough just east of the Great Lakes is proving enough lift and moisture to spark showers and thunderstorms this evening. Meanwhile, the upper level trough will close off into a low across western Pennsylvania by Friday evening. Temperatures on Friday will be a little cooler compared to Thursday as the cloud cover should become prevalent tonight before eventually breaking up by Friday afternoon.
Overnight lows will be seasonable for this time of year, with lows in the low to mid 70s.
(This afternoon through Friday night) An upper lvl trough over Western CONUS will continue to progress eastward into this weekend. Therefore, thunderstorms are likely this afternoon as result of daytime heating, orographic ascent (over the mountain areas), and the progression of the aforementioned trough. Temperatures will sit in the low 90s this afternoon and tomorrow afternoon with upper 90s to 100s along the Rio Grande.
519 PM MDT Thu Aug 19 2021 Anomalous upper level low pressure centered over northern UT early this afternoon will move northeast over WY tonight with its major trough axis crossing eastern UT and western CO between midnight and early Friday morning. The atmosphere ahead of the trough is moderately unstable south of I-70. Short term high resolution models have handled the convection so far today pretty well and they show continued bands of showers/storms rolling northeast over the area through mid evening, before consolidating into one last band along the leading edge of the upper level trough and moving southeast of the area by Friday morning. Friday will be drier as precipitable water values drop to one half inch or less behind the trough. Temperatures will remain below normal under northwest flow aloft, but warmer than today with the abundant sunshine.
702 PM EDT Thu Aug 19 2021 High pressure remains centered over the southern lakes and northern OH Valley. With a humid airmass in place (dew points in the low-mid 60s), fog is again expected.
Increasing cloudiness through the period as an upper low approaches from the northwest.
High pressure remains in control with warm and humid conditions over the Upper Mississippi Valley.
Weak high pressure will continue across the area through the weekend as moisture returns with scattered afternoon thunderstorms and light winds. Light winds and seas in weak high pressure is expected over the coastal waters through the period.
Weak ridging builds into the region by Friday morning, which should lead to a generally dry day in the wake of Fred.
As a mid-level ridge continues to shift over the area on Friday, it'll be hot and humid across all of North and Central Texas.
Cooler temperatures are expected again tonight with lows in the 30s in some locations.
Temperatures are into the upper 70s to low 80s and will cool off into the low 70s overnight. Temperatures will remain on the warm side with lows Friday morning in the low to mid 70s.
914 PM EDT Thu Aug 19 2021 A cut off upper low will drift southeast across the region for the next few days with unsettled and occasionally showery conditions lasting through the upcoming weekend. Lows by daybreak should range from around 60 in the northern mountains, to near 70 in parts of the Lower Susquehanna Valley. Temperatures will be similar to Thursday and generally range from the upper 70s to the lower 80s throughout.
Continuing from synopsis, a weak ridge will build over the Western Atlantic and into the Florida Peninsula tonight through Friday night.
Clouds and light rain showers across s-central Idaho this evening were associated with a closed low over far northern Utah. Conditions will clear out overnight as the low pulls eastward, leaving clear but smoky conditions across the area into the day Friday.
654 PM CDT Thu Aug 19 2021 (This evening through Friday) Showers and thunderstorms have developed to the west of the area over the higher terrain of the west Texas mountains. Lows tonight will be warm and muggy, likely only falling into the low to mid 70s with the higher than normal amount of moisture in the area.
No major changes to the short term forecast, expecting overnight temps to bottom out in the low to mid 70s, with some areas across N GA making it down into the mid to upper 60s. On Friday, the forecast area will be situated in a northwest flow regime aloft between the building ridge to the west and trough over the Northeast. While the impetus for development will be less clear cut than today, the combination of the moist airmass as well as any weak perturbations working around the periphery of the trough will allow for the development of scattered thunderstorms again by Friday afternoon. 5-2") lingers across the area until the fringes of the high begins to push it off towards the Gulf, so a diurnally-forced convective pattern will be maintained through the weekend.
740 PM EDT Thu Aug 19 2021 An upper level low will head eastward from the Great Lakes tonight, which will bring more showers and thunderstorms on Friday. An upper level trough just east of the Great Lakes is proving enough lift and moisture to spark showers and thunderstorms this evening. Meanwhile, the upper level trough will close off into a low across western Pennsylvania by Friday evening. Temperatures on Friday were tweaked a little cooler as the cloud cover will be rather substantial at first before eventually breaking up by the afternoon.
905 PM EDT Thu Aug 19 2021 Persistent high pressure holding over the Western Great Lakes region provided Northern Michigan with another perfect late summer day and evening. High pressure remains centered over the southern lakes and northern OH Valley. With a humid airmass in place (dew points in the low-mid 60s), fog is again expected.
(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.
418 AM EDT Fri Aug 20 2021 Low pressure slowly pulls away to the east today while a warm and humid air mass remains in place across the area. Low pressure slowly moves east today with moisture lingering in its wake. Although the low lingers near the Midcoast or downeast Maine, model forecasts seem to favor southern NH and southwest Maine with the lingering cloud cover and if that's the case then the warmest areas will actually be near the Canadian border where mid 80s are possible. Cold front associated with the leading edge of high pressure moving southeast into the Canadian Maritimes gets hung up or washed out over the far northern parts of our area tonight into Saturday, so the cooler air doesn't really arrive.
The main risk will be with localized excessive rainfall given the high moisture content and we will continue to include the whole CWA in for this limited risk.
Active weather will continue for both Friday and Saturday across the CWFA as we transition into a NW flow pattern thanks to an upper high building/strengthening across E/SE TX.
At the upper levels, north and central GA will be under northwesterly flow on the backside of an exiting upper trough, so expecting to see lesser coverage of afternoon showers and storms compared to yesterday, given the less- favorable upper pattern.
Generally a dry day for most areas today, but with an upper level trough and low over the region, a few scattered showers and thunderstorms will be possible. Showers will fill in more to the east (mostly out of the area), but as the trough tracks through the northern portion of the area, additional shower development will be possible toward Lake Ontario. Low temperatures tonight will be in the low to upper 60s. A closed upper level low across the mid-Atlantic states on Saturday will interact with tropical system Henri over the weekend.
High pressure sits just to our west and continues to dominate the sensible weather across the area. This high pressure will remain situated to our west and will continue to pivot in pockets of dry air. As Henri turns north, this will allow the ridge axis associated with the Bermuda High to surge back westward.
The Evening Update: Upper low departed Ewd today and is currently located over Wrn WY and Nrn UT. Smoke appears to be drifting Ewd in the wake of the upper low over Nrn CA and some of this should deteriorate VSBYS at RBL and RDD later tonight and into Fri. JHM Upper low to our east will slowly lose impact over our area tonight. Upper flow on the base of the trough will bring gusty winds to northern Sierra areas but winds never turn to the north with lack of digging with the trough which shouldn't bring any troublesome winds.
Temperatures are into the upper 70s to low 80s and will cool off into the low 70s overnight. Temperatures will remain on the warm side with lows Friday morning in the low to mid 70s. Temperatures will be a little warmer with highs in the upper 80s to lower 90s. With the warmer temperatures, heat index values may exceed 105 degrees over western sections of the region.
323 AM CDT Fri Aug 20 2021 A plethora of cyclones highlights the water vapor loop this morning. The most impressive is the deep trough over the Rockies, while another wave is moving slowly east across the Great Lakes. Looking to the south and east of the ridge, we find Tropical Storms Grace and Henri, which pose no threat at all to the Mid-South. We should see a lull in convective activity this evening but nocturnal showers/storms are expected to develop after midnight as the low-level jet/warm advection enhanced lift across the region.