Aikyam-Lab/Synoptic-Bench huggingface dataset:
235 AM MDT Sat Aug 7 2021 Slow moving upper trough was working through eastern Montana early this morning. Lingering light showers still popping up around the trough, so will linger low PoPs over the southeast this morning as it exits. A ridge will build back in behind the trough and much more sunshine can be expected today compared to yesterday. High temperatures will be a little warmer today with highs around 90 degrees.
Despite dewpoints in the mid/upper 50s across our CWA, the best precip chances will remain to our north on the tail end of the upper level synoptic trough over the Plains. Southerly surface winds converging with the trough this afternoon will be gusty at times.
245 AM MDT Sat Aug 7 2021 Current surface analysis shows low pressure over south central SD, with cold front extending to the south of the area. Upper level analysis shows positively tilted trough now across WY, eastern MT and into western ND. Upper trough will move east across the region through late today, with low pressure and front slowly moving east of the forecast area. High temperatures will be in the 80s to around 90 degrees over the plains, with 70s over the higher Black Hills.
1133 PM MDT Fri Aug 6 2021 Slow progressing upper trough will support chances for showers and thunderstorms the next two days. Western CONUS upper ridge will briefly breakdown in the period as series of stronger NE Pac impulses traverse the northern tier allowing strong cold fronts into the northern CONUS. A period of breezy NW winds may materialize in the morning behind the trough.
However, lower level convergence and influence from Central Plains trough should be enough to overcome cap farther south into the panhandles and northwest Oklahoma (possibly building down into west central Oklahoma during the evening).
/GG/ Prior discussion below: Tonight and Saturday: As the upper trough passing across the region, it has combined with heating and ample moisture to generate some showers and isolated thunderstorms across the region. Another quiet night is expected as the upper trough continues to track east. For tomorrow, the upper ridge will begin building back east over our area. Heat indices will remain tolerable for the most part with the highest heat indices being in the west around 95-100 degrees.
101 AM CDT Sat Aug 7 2021 Mainly VFR conditions expected through the forecast period with high pressure building into the region. Upper ridging begins to nose into the region overnight and Saturday, providing subsidence and drier air aloft to diminish rain chances. As the summertime upper ridge builds back into the area, summertime heat and humidity returns, and heat indices will reach the 105 to 109 range over most of the area.
945 PM PDT Fri Aug 6 2021 Cold front will sweep across the Inland Northwest Saturday night.
With that said, an eventual westerly wind component early this afternoon should aid in the best PoPs along the higher terrain bordering Virginia. As a result of the cloud cover and chance showers/storms, highs today will stay seasonably cool in the low to mid 80s.
250 AM EDT Sat Aug 7 2021 Early this morning, the axis of an upper trough was moving into Indiana. After 12Z today, the upper trough will continue to move east and provide forcing to mainly the northeastern forecast area. As an upper ridge begins to build in tonight, some energy moving around its periphery could spark an isolated shower or storm.
GOES East satellite imagery shows a mid/upper-level trough advancing eastward into the Ohio Valley. Cloud cover and warm south/southwest flow ahead of the trough will keep the forecast area quite warm tonight. The encroachment of the trough will effectively cool the mid-levels enough such that MLCAPE values rise to ~1000 J/kg by the afternoon as the near-surface layer warms in response to insolation.
310 AM EDT Sat Aug 7 2021 Scattered showers and a few thunderstorms are possible today and Saturday with a passing trough. GOES East satellite imagery shows a mid/upper-level trough advancing eastward into the Ohio Valley. Cloud cover and warm south/southwest flow ahead of the trough will keep the forecast area quite warm tonight. The encroachment of the trough will effectively cool the mid-levels enough such that MLCAPE values rise to ~1000 J/kg by the afternoon as the near-surface layer warms in response to insolation.
Warmer temperatures are on tap for the next several days.
This will result in breezy south to southwest boundary layer flow and warmer temperatures. Plentiful breaks in the mid level cloud will allow for these warmer temperatures and moderate instability. Storms will develop along the trough line over southwest Kansas and also across the western high plains in the wake of the weak front.
A well defined upper level trough will provide the necessary overarching forcing for storm development/maintenance. Meanwhile at the surface, a trough will set up. Most suggest a warm front extending out of far NE SD and across MN with a trailing cold front across central to eastern South Dakota. Very slow movement to the east with this trough and associated fronts.
For Saturday, an upper trough will move into the east Tennessee valley during the next 24 hours. An upper jet streak associated with the upper trough will enhance the lift over the area with a marked cooling of the mid-levels with 500mb temperatures dropping from -6 to -11. Changes coming overnight with upper trough moving into east Tennessee today. As upper trough moves into the east Tennessee valley during the next 24 hours.
/Issued 1117 PM CDT Fri Aug 6 2021/ /Through Saturday/ A ridge aloft will keep dry and subsident air across the region through Saturday.
The broad upper trough is still right over our area. The trough axis will slowly shift eastward through the daylight hours. With the trough still in the vicinity expect some showers and a couple thunderstorms mainly along and east of I-65 during the daylight hours. Rain chances will shut off this evening as the upper trough moves out.
905 PM PDT Fri Aug 6 2021 Cold front will sweep across the Inland Northwest Saturday night.
/issued 928 PM CDT Fri Aug 6 2021/ Wx map shows weak high pressure ridging across the Gulf, with light south to southwest winds across the region. With the onshore flow back, dewpoints have risen once again into the lower 70s, still could be worse for this time of year. Saturday morning lows in the lower 70s expected, likely the last of the lower 70s for a while.
The main thunderstorm concern comes later this evening and overnight as the trough meanders into the Plains. Initially discrete cells will likely grow upscale rather quickly as a result of only modest bulk shear around 25-30 kts, MLCAPE of 2000+ J/kg, and increasing large-scale ascent ahead of the progressing trough. CAMs and medium range models differ in the speed of the trough and, thus, when convection will reach the western part of the forecast area. Over the past few days, models have trended toward a slower progression of the trough, similar to what the latest HRRR runs have shown, so think the HRRR has a good handle on the timing and evolution of the event.
405 AM EDT Sat Aug 7 2021 Mean layer ridging persists over the western North Atlantic. The low level ridge axis stretches west across Florida and supports gentle east to southeast breezes across the Florida Keys. The low level ridge axis will lift northward over the next couple of days, allowing a little more breeze to bathe the Keys in warm and moist easterlies.
For the rest of the day, southerly winds gusting to around 20 mph are expected to remain in place as temperatures top out in the low-to-mid 90's. The mass fields for this system have most of the support in the lower levels with decent 700 and 850 mb jet streaks, and the mid-levels struggling to reach 40 kts, and leaving most of the area with around 25 kts of effective bulk shear. The main concerns with these storms will be severe winds due to the higher CAPE and clustering storm mode, with large hail and an isolated tornado or two being secondary threats due to the steep lapse rates and veering low-level wind profile.
1035 PM CDT Fri Aug 6 2021 Latest water vapor imagery is showing an upper trough moving across Missouri and Illinois while latest surface analysis is showing little reflection of this trough at the surface with a stationary front well north of the area across the Upper Midwest and the northern Plains. There are some scattered showers and isolated thunderstorms over central Illinois and southeast Missouri associated with this trough, and there still may be isolated showers and thunderstorm develop ahead of this trough over the eastern half of the area late this afternoon before it moves east of the region tonight. Then mainly dry weather is expect tonight into Saturday evening as the latest run on the HREF is showing the upper ridge currently over the Plains building into the Midwest.
Dry conditions are expected to prevail across the region as high pressure begins to temporarily rebuild.
At the surface, a lee trough is present in E NM while surface dewpoint depressions across the Panhandles are in the 10 to 20 degree range. Saturday, as the aforementioned wave continues to shift eastward, cross-barrier flow aloft will increase accordingly, with the lee trough strengthening and shifting eastward as a result. Progged hodographs show some turning in the low levels but generally straight profiles in the 2-6km layer, suggesting any supercells will tend to split, with upscale growth occurring due to storm mergers.
206 AM MDT Sat Aug 7 2021 Current surface analysis shows cold front laying across central Colorado early this morning. Southeast Wyoming and Nebraska Panhandle on the cooler north side of this front. Nice day today expected across the area as high pressure builds slowly back into the area.
1055 PM CDT Fri Aug 6 2021 (This evening through Saturday) Dry and warm tonight with lows in the low to mid 70s.
An upper trough axis is currently centered over north Alabama, and drier air is filtering in aloft behind this axis. Isolated to scattered thunderstorms will be possible later today, under the influence of the upper trough axis.
313 AM CDT Sat Aug 7 2021 Upper trough over northern Alabama exiting the area this morning. Temperatures at 3 AM CDT this morning were generally in the lower 70s away from marine influences.
TWH Slow moving upper trough was working through eastern Montana early this morning. Lingering light showers still popping up around the trough, so will linger low PoPs over the southeast this morning as it exits. A ridge will build back in behind the trough and much more sunshine can be expected today compared to yesterday. High temperatures will be a little warmer today with highs around 90 degrees. Will highlight that in the fire weather forecast for now, as focus will be on Sunday for the critical fire weather day with warmer temperatures, low RHs and stronger winds, along with a frontal passage. TWH A strong cold front is set to move into southeastern Montana Sunday afternoon and evening.
A deeper marine layer and stronger onshore flow with a passing of low pressure will keep a gradual cooling trend going through the weekend.
Outside of that, and until the mid level trough passes through, isolated showers and storms will continue to form.
/issued 202 AM CDT Sat Aug 7 2021/ SHORT TERM (Now through Sunday): The subtropical ridge gradually builds across Texas through the weekend with a large 500mb trough across the eastern CONUS. Low pressure across the Plains and high pressure across the eastern Gulf of Mexico will strengthen the pressure gradient along the lower Texas coast into Sunday, bringing breezy southeasterly winds during the afternoon hours.
Warmer and dry through the weekend. On Sunday trough energy drops through the Pacific NW, with jet energy clipping northern NV Sunday afternoon and evening.
836 AM EDT Sat Aug 7 2021 Scattered showers and a few thunderstorms are possible today and Saturday with a passing trough. Main player in the weather will be the approaching upper trough which should spawn convection later this afternoon. The encroachment of the trough will effectively cool the mid-levels enough such that MLCAPE values rise to ~1000 J/kg by the afternoon as the near-surface layer warms in response to insolation. By Sunday, mid-level ridging will begin to build across the area, but not before one last trough helps initiate convection across western PA and northern WV.
Mid level short wave currently over the lower OH Valley will scoot east today, allowing ridging to move in from the west. This H50 ridge will help to keep things high a dry through Sunday.
616 AM MDT Sat Aug 7 2021 Current surface analysis shows cold front laying across central Colorado early this morning. Southeast Wyoming and Nebraska Panhandle on the cooler north side of this front. Nice day today expected across the area as high pressure builds slowly back into the area. Upper high continues to build back over the area SUnday with 700mb temperatures climbing from +8C this morning to +18C Sunday afternoon.
Variable mid to high clouds streaming across central PA this morning in broad southwest flow ahead of a fairly disorganized split upper trough moving through the central GLAKS and OH Valley. Best chances for isold-sct convection this afternoon are over the northwest mountains where a lake breeze may combine with weak forcing from the split upper trough traversing the region. As noted by previous shift, farther southeast into the lower Susquehanna Valley, stronger capping and CIN will keep rain chances lower there. Split upper trough exits to the east tonight as ridging builds into the Middle Atlantic. Highs will range through the 80s to near 90, with noticeable humidity as dewpoints rise through the lower to middle 60s.
High pressure building over the region will keep generally quiet conditions over South Texas today and Sunday.
A disturbance associated with the upper trough will pass over New Mexico today, resulting in some convection across the Sacramento Mountains. Sunday will be slightly warmer than Saturday with highs in the upper 90s across the Permian Basin and 100s along the Trans Pecos and Rio Grande. Storms look to develop off the higher terrain of SE New Mexico and attempt to move into TX, but drier air in the mid levels will kill off storms fairly quickly.
528 AM EDT Sat Aug 7 2021 Scattered showers and a few thunderstorms are possible today and Saturday with a passing trough. GOES East satellite imagery shows a mid/upper-level trough advancing eastward into the Ohio Valley. Cloud cover and warm south/southwest flow ahead of the trough has kept the forecast area quite warm overnight. The encroachment of the trough will effectively cool the mid-levels enough such that MLCAPE values rise to ~1000 J/kg by the afternoon as the near-surface layer warms in response to insolation. By Sunday, mid-level ridging will begin to build across the area, but not before one last trough helps initiate convection across western PA and northern WV.
958 AM CDT Sat Aug 7 2021 Showers and thunderstorms are ongoing across our southern Middle Tennessee counties associated with the upper-level trough moving through. Shower and thunderstorm activity should mainly be confined to the I-65 corridor eastward today as the trough moves off to the east.
An upper-level trough moves over the region today with a weak surface reflection. We will see the best coverage of showers and isolated storms during the day in the east as the trough moves through and eventually out. On Sunday, we will see more of the typical hit and miss showers and storms as ridging really begins to take shape.
Highs will reach the low 90s along the coast and mid 90s inland, with peak heat indices between 101 and 106.
The broad upper trough is still right over our area. The trough axis will slowly shift eastward through the daylight hours. With the trough still in the vicinity expect some showers and a couple thunderstorms mainly along and east of I-65 during the daylight hours. Rain chances will shut off this evening as the upper trough moves out. Upper ridging moves into the area on Sunday which will suppress PoPs. The upper ridge overspreads the southern US which will mean hot conditions for Middle Tennessee and diurnal shower and storm chances.
An upper level ridge will amplify over the Rockies and High Plains Sun-Sun night. An associated lee cyclone, presently centered invof the southern KS/CO border (between Lamar-Syracuse), will progress eastward into central KS this afternoon and evening. While weak low-level convergence invof the aforementioned lee cyclone may be playing a role. possibly augmented by a narrow corridor of low-level warm advection/frontogenesis -- as the LLJ in southwest KS advects a warmer and slightly drier H85 airmass northward (and upward) atop a locally denser, rain-cooled, convectively modified airmass in northwest KS. Persistent/ongoing convection this morning introduces further complexity /additional uncertainty/ with regard to the evolution of the mesoscale pattern this afternoon -- altering low-level height/wind fields (including the location/orientation and subsequent evolution) of the aforementioned lee cyclone, for example.
523 AM MDT Sat Aug 7 2021 Current surface analysis shows low pressure over south central SD, with cold front extending to the south of the area. Upper level analysis shows positively tilted trough now across WY, eastern MT and into western ND. Upper trough will move east across the region through late today, with low pressure and front slowly moving east of the forecast area. High temperatures will be in the 80s to around 90 degrees over the plains, with 70s over the higher Black Hills. Much warmer air returns for Sunday, ahead of a stronger cold front moving across the Rockies.
As it stands, models seem to be in an agreement that the lower level moisture influx will hold on through at least the early afternoon with episodic showers moving across the island chain at times. Otherwise, the pattern has not changed, we remain south of a ridge axis situated across south Florida and the entirety of the Gulf of Mexico. Thereafter, ridge axis will lift north in response to a strengthening Bermuda High.
542 AM MDT Sat Aug 7 2021 Compared to recent days, today's weather should be fairly benign as a low-amplitude ridge builds over the region.
As a result of the cooler air mass filtering in, anticipate high temperatures this afternoon to follow suit and top out 5-10 degrees cooler than yesterday. High pressure in control across the Great Basin and Four Corners will lead to another dry day on Sunday, though temperatures will quickly rebound back to a few degrees above normal.
A weak, flat ridge will be positioned over southern Arizona and New Mexico along with the sub-tropical ridge through the northern Gulf into southeast Texas through the weekend. High temperatures are generally forecast to warm into the low to mid 90s today and a degree or two warmer in some spots on Sunday.
Warmer temperatures are on tap for the next several days. Today, a ridge will build in across the Mississippi River Valley.
Subtropical ridging originating from the western Atlantic Ocean is forecast to slightly build in strength, with a 500 hPa center of around 593 decameters positioned directly over the region. Maximum temperatures will generally be in the lower 90s through the weekend, while minimum temperatures should be in the mid/upper 70s regionwide.
79 Previous Discussion: /Through Saturday/ A ridge aloft will keep dry and subsident air across the region through Saturday. /Issued 321 AM CDT Sat Aug 7 2021/ /Sunday onward/ Mid-level ridging will continue through the next several days.
Despite dewpoints in the mid/upper 50s across our CWA, the best precip chances will remain to our north on the tail end of the upper level synoptic trough over the Plains. Southerly surface winds converging with the trough this afternoon will be gusty at times. An upper level sub-tropical ridge will be in place across the southern tier of the CONUS at the beginning of the period Sunday with a fairly progressive jet stream across the northern CONUS and southern Canada.
Today Through Sunday Night Early this morning, surface observations showed high pressure centered to the east of Arkansas. The upper level trough which helped sustain convective activity yesterday was shifting east of the Mississippi River. High temperatures should be a few degrees warmer with less cloud cover expected. Though upper ridging will begin to build in for the upcoming week, there will be a trough moving through the Midsouth region on Sunday around the periphery of the ridge. By the evening Sunday, any remaining convection will diminish, and the upper ridge will expand in earnest.
Partial cloudiness should decrease slightly by late day as weak troughiness slowly slides east of Indiana. Early this morning, the axis of an upper trough was moving into Indiana. After 12Z today, the upper trough will continue to move east and provide forcing to mainly the northeastern forecast area. As an upper ridge begins to build in tonight, some energy moving around its periphery could spark an isolated shower or storm. On Sunday, the upper ridge will build into the area, and mid level temperatures will warm.
405 AM CDT Sat Aug 7 2021 Mid level short wave currently over the lower OH Valley will scoot east today, allowing ridging to move in from the west. This H50 ridge will help to keep things high a dry through Sunday.
A broad ridge over the desert southwest continues to dominate our weather even as it weakens overhead. Plenty of moisture in place as we continue to see a steady moisture push up the gulf, with typical 24 hour circulation through the lower deserts before recurving into our area with afternoon diurnal wind trends. Ensembles and ensemble means are reconsolidating the mid level high center to our east over the next 48 hours, which will re-engage a deeper monsoonal pattern, encourage better storm structure, and bring inverted trough activity back into the picture. Unlike yesterday, there are no clear convective complex and organized outflow signals to push storms toward the Tucson area and (after being worked over yesterday) the lower deserts, so we're going with below average coverage for valley storms.
/Today through Sunday/ Upper-level ridge to swing east across the region through the weekend allowing for subsidence aloft to bring warmer temperatures to the region.
MCS system will usher east across the Plains today along along a warm frontal boundary, eventually becoming more disconnected from the better reservoir of higher theta-e air, into a region of diminishing MUCAPE and poor shear as it approaching Lake Michigan. H850 temperatures under the ridge will increase to around 18C at 18Z, with surface temperatures ranging in the upper 80s, tapping 90 at some locations pending cloud trends. Dew points increase into the lower 70s, raising heat indices into the lower 90s for all locations across southern Michigan.
Early this morning, the axis of an upper trough was moving into Indiana. After 12Z today, the upper trough will continue to move east and provide forcing to mainly the northeastern forecast area. As an upper ridge begins to build in tonight, some energy moving around its periphery could spark an isolated shower or storm. On Sunday, the upper ridge will build into the area, and mid level temperatures will warm.
Westerly flow is setting up over the Northern Rockies ahead of the approaching low-pressure system. This flow pattern will cause breezy winds this afternoon with high temperatures slightly warmer than yesterday. The upcoming cold front and low-pressure system begin to move into north-central Idaho and northwest Montana tonight. A narrow swath of above-normal moisture will associate with the cold front, that along with a parallel upper-level jet will produce a slow- moving area of rain, oriented southwest to northeast. Showers will remain through Sunday night as the low passes through the region.