Aikyam-Lab/Synoptic-Bench huggingface dataset:
344 AM MDT Tue Jul 21 2020 Satellite imagery and 500 mb RAP analysis showed a broad trough across the northern half of the country this morning. Behind this disturbance, northwest flow prevailed over the region, with areas of high pressure across the desert southwest and southeastern CONUS. At 2:00 PM MT, a cold front was draped from west to east across the center of the region with mostly sunny skies. The cold front is expected to help trigger thunderstorms this afternoon and evening, as an upper wave passes through the northwest flow. Temperatures should be slightly cooler behind the front, with highs in the upper 80s to low 90s. An upper ridge will extend from the Rockies to the Ohio River Valley with weak southwest flow aloft over the Tri-State area.
Weak upper ridging continues through the period. As has been the case over the past several days, this upper ridging not strong enough to suppress diurnal convection given the strong surface heating again today and Wednesday. As mid and upper level ridge gets shunted west, a NW flow regime develops across the area which will aid in the progression of backdoor front through the northern sections.
/28/ Much of the same will occur today as the region will be on the western side of an upper ridge that is centered across the Atlantic. Temperatures today will once again rise into the lower and mid 90s with dewpoints in the 70s.
An upper level subtropical height ridge centered over Georgia and the Carolinas will expand westward and amplify over the plains and mid-MS River valley, displacing the stronger westerlies currently across those regions. Looking beyond the 7 day forecast, there are indications in the ECMWF and Canadian models that the upper ridge will build further west over the Rockies, while a longwave trof develops over New England.
552 AM MDT Tue Jul 21 2020 08z surface analysis had low over west central MN with trailing cold front into northeast CO. Wednesday, upper level ridge builds into the northern plains in response to upper through over the west coast. 850-700mb thermal ridge builds into the CWA with warmer temperatures.
/Issued 720 AM EDT Tue Jul 21 2020/ Weak upper ridging continues through the period. As has been the case over the past several days, this upper ridging not strong enough to suppress diurnal convection given the strong surface heating again today and Wednesday. As mid and upper level ridge gets shunted west, a NW flow regime develops across the area which will aid in the progression of backdoor front through the northern sections.
Highs will be in the upper 80s to the lower 90s with heat index values in the middle 90s to around 100. An upper level ridge of high pressure will then move over the region late this week into the weekend.
The precip with this system may have a strong gradient north south as the moisture moves up against the high to the NE.
High pressure settles across the region for the day today, and dry conditions are expected as a result. Below average temperatures (highs in the mid-70s to low 80s) are forecast as well, under lower heights aloft from the passing trough. By Wednesday, a low amplitude upper level ridge begins to shift east and amplify as it does so across the Northern Plains.
A low pressure system just off the California coast will turn flow more easterly today. That being said, the lower atmosphere's pump will already be primed from earlier precipiation. As clouds move in Wednesday and the lower atmosphere moistens, much of the forecast area will drop nearly 10 degrees vs Tuesday's highs.
Although the wave is pressing west away from the Keys, a solid south-southeasterly low-level jet pushing north-northwest through the Straits of Florida should be upon the Lower Keys in the next hour or two. As the low level jet nears the Lower Keys, the inflow parcels will be worked over by previous rains and evaporative cooling. Therefore, we feel the threat for mesocyclones near the Keys is low at this time.
/issued 340 AM CDT Tue Jul 21 2020/ SHORT TERM (Today through Wednesday): A relatively flat mid-level height field will lie over the area in the short term, with broad high pressure at the surface. High temperatures will remain in the 90s east to the low 100s out west the next couple of days under mostly sunny to partly cloudy skies. Tropical cyclone formation probability in the next 48 hours is rated as low.
902 AM CDT Tue Jul 21 2020 Another typical summer day is in store as high temperatures reach the low to mid 90s this afternoon. Mid and upper level ridging will remain modest, allowing the development of diurnal showers and thunderstorms. High pressure over the region will continue to gradually weaken as activity to the north tries to break down the ridge. With weakening high pressure over the Tennessee Valley, expect more and more afternoon thunderstorm activity over the next couple days. Broad-view look at the CONUS shows an amplifying ridge over the central CONUS which will play a role in our weather going into the weekend. As the ridge builds up, it shoves the amplifying upper-level trough east into the New England states.
Temperatures trend warmer today through Wednesday.
Prior discussion below: Much of the same will occur today as the region will be on the western side of an upper ridge that is centered across the Atlantic. Temperatures today will once again rise into the lower and mid 90s with dewpoints in the 70s.
317 AM PDT Tue Jul 21 2020 Slow cooling will continue today as high pressure slowly weakens.
742 AM EDT Tue Jul 21 2020 The upper ridge will continue to dominate the weather early this week before weakening later in the week as an upper trough moves into the Ohio Valley and Mid Atlantic region. Another typical Summer day is expected today under the influence of the persistent upper ridge anchored over the southeast and Carolinas. Temperatures today may be slightly cooler than yesterday but not by much as highs are expected to be in the mid to upper 90s again. Wednesday and Wednesday Night: Ridging at the surface and aloft will persist over the western Atlantic, resulting in strong subsidence and a southerly low-level return flow.
The highest chance for showers and isolated storms will be early to mid afternoon, before the east coast sea breeze pushes storms to the western side of the peninsula later this afternoon. Highs today ranging from the upper 80s along the Treasure Coast, to the low 90s from Orlando northward.
Temperatures will max out in the middle 80s with dewpoints in the lower 70s so no excessive heat concerns for today. Weak westerly flow alof continues into Wednesday with very weak short wave trof along with weak surface and outflow boundaries in the region as we move into Wednesday afternoon and overnight we may see the development of another somewhat weaker MCS set up along a weak convergence zone underneath increasing ridging aloft from easten Nebraska through northern Missouri.
The upper ridge over the area will weaken and flatten today for slightly cooler conditions.
418 AM CDT Tue Jul 21 2020 For today and tonight, the broad upper level ridge of high pressure which covers the southern half of the United States will persist through tonight. This will result in one more day of just enough favorable west to west northwest favorable steering flow aloft across the OK and TX Panhandles to bring showers and tstms into our region from the higher terrain of southeast CO and eastern NM.
The remaining TAF sites will see an isolated chance (chances are slightly higher within the higher terrain of NW AR and E OK) for diurnal storm development this afternoon but confidence is too low to warrant a mention in the TAF at this time. High temperatures today will likely be a bit cooler than the past couple days due to increased cloud cover.
500 AM MDT Tue Jul 21 2020 Upper ridge begins building into the northern plains as a trof digs into the Pacific Northwest.
932 AM EDT Tue Jul 21 2020 High pressure will build over the area this afternoon into tonight.
The upper level ridge continues to be the main feature in the short-term forecast period. With elevated upper heights, temperatures will climb into the low to mid 90s for most locations with heat indices of around 100 degrees for the central and southern Tennessee Valley. Otherwise, another day of convection is expected, perhaps with better coverage as the ridge migrates east, thus all sites feature VCTS mention with PROB30s for TSRA, timing based on CAM consensus. CDG Chattanooga Airport, TN 95 74 93 73 93 / 50 20 60 20 60 Knoxville McGhee Tyson Airport, TN 95 74 93 73 91 / 50 30 70 30 70 Oak Ridge, TN 96 73 93 72 90 / 50 30 60 30 70 Tri Cities Airport, TN 93 69 90 69 88 / 60 30 70 40 70.
High pressure building into the region today is on track to bring warm temperatures with highs around 5 degrees above normal. Wednesday is set to be the warmest day of the week in response to the break-down of the ridge and an approaching trough. Moisture is increasing in the Great Basin, and southwesterly flow ahead of the aforementioned trough will direct this moisture into central Idaho and western Montana on Wednesday.
330 AM MDT Tue Jul 21 2020 Temperatures trend warmer today through Wednesday.
High pressure will dominate our weather with seasonable temperatures this afternoon. During this period a broad upper level trough moves through.
As the persistent ridging continues, the extreme heights and heat have relented. Upper heights building slightly from the Rockies into the central plains will bridge with broader height rises across the southern plains by the end of the week in advance of a tropical-type system crossing the Texas coast early this weekend.
243 PM CDT Tue Jul 21 2020 Skies are partly cloudy across the Mid-South this afternoon with temperatures generally in the low to mid 90s. Temperatures will remain seasonal on Wednesday with highs in the low to mid 90s.
1244 PM EDT Tue Jul 21 2020 Chances of showers and thunderstorms will increase late this afternoon into tonight as a warm front lifts northward. Some convective redevelopment is possible Wednesday afternoon as a northern stream trough tracks across the Great Lakes region with local area on southern periphery of this forcing. This redevelopment would likely occur along either remnant outflow boundaries from overnight showers/storms or perhaps along weak synoptic troughing with the northern stream trough.
1257 PM EDT Tue Jul 21 2020 Chances of showers and thunderstorms will increase late this afternoon into tonight as a warm front lifts northward. Some convective redevelopment is possible Wednesday afternoon as a northern stream trough tracks across the Great Lakes region with local area on southern periphery of this forcing. This redevelopment would likely occur along either remnant outflow boundaries from overnight showers/storms or perhaps along weak synoptic troughing with the northern stream trough.
Max temperature should stay relatively low with the cloud cover but still reach the average CT in the low 80s.
242 PM EDT Tue Jul 21 2020 Weak ridging aloft is expected to continue through the forecast period. Wednesday will bring a similar story as today with weak ridging aloft and slightly higher pops across the northern tier. Temperatures on Wednesday are forecast to be fairly similar to this afternoon, but slightly cooler across portions of northern Georgia due to increased cloud cover.
247 PM EDT Tue Jul 21 2020 The upper ridge will continue to dominate the weather early this week before weakening later in the week as an upper trough moves into the Ohio Valley and Mid Atlantic region. Temperatures today may be slightly cooler than yesterday but not by much as highs are expected to be in the mid to upper 90s again.
951 AM PDT Tue Jul 21 2020 Slow cooling will continue today as high pressure slowly weakens.
The lower atmosphere will be pretty dry so the main impact with initial storms will be gusty and erratic outflow winds and frequent lightning.
Seasonable temperatures are anticipated through the period with highs in the low 90 and lows in the low 70s. One possibility is for storms on the High Plains to roll east during the night.
131 PM PDT Tue Jul 21 2020 A couple afternoon thunderstorms are again possible over the higher elevations of the Sierra Nevada this afternoon.
Cloud cover will keep temperatures a couple degrees cooler, with highs Wednesday in the lower to mid 90s. Lows tonight will be in the lower to mid 70s.
143 PM EDT Tue Jul 21 2020 An upper trough stretches from the Eastern Panhandle to about the Yucatan.
This is indicative of very limited instability in the low levels ahead of a weak frontal boundary (draped from Columbus to Tekamah at 3 PM). The entire region should be dry after 10 PM, with temperatures falling into the low to mid 60s by 6 AM.
Maxes in the NW could be a notch cooler with all the cloud cover there. Storms driven by main short wave trough moving through NW PA now and should be peaking soon, then die off through sunset.
232 PM EDT Tue Jul 21 2020 High pressure will build over the area this afternoon into tonight.
214 PM MDT Tue Jul 21 2020 Ridge building over the area is producing sunny skies across the northern Rockies this afternoon. 700mb temperatures climb above 15c which is well above the threshold that caps off convection over the lower elevations. Given the increased atmospheric moisture, can't rule out an isolated thunderstorm over the mountains, but these should dissipate pretty quickly once they come off the higher terrain.
Expect additional storm development this afternoon to be focused more near this feature and over the higher terrain areas, though isolated storms will be possible just about anywhere. The remaining TAF sites will see an isolated chance (chances are slightly higher within the higher terrain of NW AR and E OK) for diurnal storm development this afternoon but confidence is too low to warrant a mention in the TAF at this time. High temperatures today will likely be a bit cooler than the past couple days due to increased cloud cover.
The surface cold front has made its way down into Kansas, but is a bit difficult to discern and has been disrupted by thunderstorm outflow. Severe chances look low as the best support remains near the low-level jet axis to the west. After a lull Wednesday morning, activity could pick up again along the returning warm front by late Wednesday afternoon. More storms could erupt as the front returns north as a warm front and severe parameters indicate that we could get some severe weather by late afternoon/evening Wednesday as another perturbation moves by.
Isentropic accent and remnants of a MCV ahead of a cold front from IA down into NE KS has helped continue showers and isolated storms this morning. Another area to watch will be over NE KS and NW MO that is developing along the cold front and surface convergence. The main area of fog will correspond to where the lower clouds clear out, which will mainly be in a line from the KC Metro up into Kirksville. The lowest visibilities will be up into NW Missouri where 1/4-1/2 mile visibility is possible. This will lead to a rather cooler day in July before temperatures start to go back up. Upper level ridging will start to build back into the area on Wednesday with a stationary boundary setting up south of MO.
The mid to upper level ridge expected to prevail across the Southern and SE U.
349 PM EDT Tue Jul 21 2020 High pressure will persist through the weekend.
1101 AM MDT Tue Jul 21 2020 08z surface analysis had low over west central MN with trailing cold front into northeast CO. Wednesday, upper level ridge builds into the northern plains in response to upper through over the west coast. 850-700mb thermal ridge builds into the CWA with warmer temperatures.
1037 AM CDT Tue Jul 21 2020 Fog has, for the most part, dissipated and the mixing out of the low stratus clouds commenced a couple hours ago. High pressure settles across the region for the day today, and dry conditions are expected as a result. Below average temperatures (highs in the mid-70s to low 80s) are forecast as well, under lower heights aloft from the passing trough. By Wednesday, a low amplitude upper level ridge begins to shift east and amplify as it does so across the Northern Plains.
315 PM EDT Tue Jul 21 2020 Water vapor imagery highlights a mid-upper tropospheric trough digging south through the Gulf of Mexico and the Yucatan Peninsula. East of the trough, an induced anticyclone aloft has aided the exhaust of deep convection across Cuba, the Florida Keys, and South Florida. This low level curvature is associated with a tropical wave moving west through the southeastern Gulf of Mexico, just to the west of the Dry Tortugas. Breezes will relax somewhat tonight and Wednesday, although the tenacious ridging to our north will maintain a tight gradient.
Another typical summer day is in store as high temperatures reach the low to mid 90s this afternoon. Mid and upper level ridging will remain modest, allowing the development of diurnal showers and thunderstorms. High pressure over the region will continue to gradually weaken as activity to the north tries to break down the ridge. With weakening high pressure over the Tennessee Valley, expect more and more afternoon thunderstorm activity over the next couple days. Broad-view look at the CONUS shows an amplifying ridge over the central CONUS which will play a role in our weather going into the weekend. As the ridge builds up, it shoves the amplifying upper-level trough east into the New England states.
Cooler and drier air is being brought in behind the front as well, leading to overnight lows in the upper 50s to lower 60s. Overnight, the low level jet forms off to our west into central SD and will be moving slowly to the east. Expect afternoon highs to In the late afternoon, the activity will progress northeastwards as the ridge begins to lift. The upper level ridge starts to flatten as an approaching vorticity maximum is riding the ridge off to the west. Near the surface, a warm front extending down from Montana towards the Iowa/Nebraska border lifts northeastwards towards the area. As far as severe thunderstorm potential, instability values aren't bad but they decrease as the wave reaches the area and shear values are barely there to speak of outside of the low levels.
Will keep most PoPs in the chance range for tomorrow, with the higher numbers in the afternoon.
128 PM EDT Tue Jul 21 2020 The upper ridge will continue to dominate the weather early this week before weakening later in the week as an upper trough moves into the Ohio Valley and Mid Atlantic region. Temperatures today may be slightly cooler than yesterday but not by much as highs are expected to be in the mid to upper 90s again. Wednesday and Wednesday Night: Ridging at the surface and aloft will persist over the western Atlantic, resulting in strong subsidence and a southerly low-level return flow.
NHC has a 30% chance of this wave developing into a tropical cyclone over the next 48 hours as it moves into the central and eventually western Gulf.
Increased low level moisture ahead of the low tracking across central WI should lead to stratus clouds for late tnt-Wed AM. After a weak cold front moves through in the morning, clouds should become scattered.
Temperatures will max out in the middle 80s with dewpoints in the lower 70s so no excessive heat concerns for today. Weak westerly flow aloft continues into Wednesday with very weak short wave trof along with weak surface and outflow boundaries in the region as we move into Wednesday afternoon and overnight we may see the development of another somewhat weaker MCS set up along a weak convergence zone underneath increasing ridging aloft from eastern Nebraska through northern Missouri.
A low pressure system just off the California coast will turn flow more easterly today. That being said, the lower atmosphere's pump will already be primed from earlier precipitation.
Overnight lows will generally be in the low to mid 70s. For Wednesday, similar conditions are expected with scattered late morning through afternoon convection and highs in the low to mid 90s.
415 PM EDT Tue Jul 21 2020 High pressure will build over the area tonight.
239 PM CDT Tue Jul 21 2020 Forecast highlights in the short term period will be isolated showers/thunder this afternoon central and east, followed by warmer temperatures and more humid conditions for Wednesday. Currently, S/WV mid level trough moving east across northern Minnesota with northwest flow aloft across North Dakota along with a subtle embedded wave working its way across the state. Strengthening southerly flow will bring into the region warmer air and increasing sfc dewpoint temperatures.
The upper level ridge continues to be the main feature in the short-term forecast period. With elevated upper heights, temperatures will climb into the low to mid 90s for most locations with heat indices of around 100 degrees for the central and southern Tennessee Valley.
237 PM CDT Tue Jul 21 2020 Latest water vapor imagery shows a trough over the Mid and Upper Mississippi Valleys, with ridging over the western CONUS and anchored over the southeast. With decent radiational cooling once again tonight, lows will fall into the lower 70s by daybreak.
The upper pattern continues to be messy with the upper ridge over the southern Rockies tries to push slowly toward the High Plains tonight and into tomorrow, but there remains some troughing over Oklahoma into tomorrow, which will likely focus the shower and storm chances a little farther east and south tomorrow.
an area of low pressure was making its way east northeast across Kansas. isolated to widely scattered showers were occurring in the higher terrain of Southeast Oklahoma and Western Arkansas. a ridge of high pressure is progged to build back over the region. The building ridge should keep the tropical system in Texas as it moves further inland. warming temperatures for the region and daily diurnal chances for convection mainly within the higher terrain of Southeast Oklahoma and Western Arkansas are forecast.
223 PM EDT Tue Jul 21 2020 Upper level energy will cross the region this afternoon and help lift a warm front northeast of the I-70 corridor this evening.
An upper low near the northern California coast will start to spread moisture into southern Oregon this afternoon. Otherwise, expect mostly clear skies and hot temperatures, with highs near 100 degrees in the lower valleys.
The lack of clouds has allowed temperatures to soar into the low 90s yet again today. Temperatures could end up a few degrees cooler on Wednesday given the unsettled weather, and could be much cooler in some areas depending on which areas are most persistently impacted by convection.
330 PM EDT Tue Jul 21 2020 Synopsis/Discussion/Marine Low pressure will track through the Great Lakes tonight with showers and thunderstorms through early Wednesday. Then high pressure builds in with generally fair weather through the end of the week.
Approaching upper level trough will bring an increase in westerly winds later today along the east slopes of the Cascades. 12z models remain consistent with a slight chance of thunderstorms over northeast Oregon late Wednesday as the trough moves across the area.
Fog has, for the most part, dissipated and the mixing out of the low stratus clouds commenced a couple hours ago. High pressure settles across the region for the day today, and dry conditions are expected as a result. Below average temperatures (highs in the mid-70s to low 80s) are forecast as well, under lower heights aloft from the passing trough. By Wednesday, a low amplitude upper level ridge begins to shift east and amplify as it does so across the Northern Plains.
Return flow is strengthening across northeast WY in advance of deepening lee trof, but best instability remains to our south. Activity may be ongoing early Wednesday morning in south-central SD, but larger scale subsidence behind departing wave and short wave ridge moving in should keep convection fairly limited the rest of the day Wednesday. Much warmer temps expected with highs into the 90s over northeast WY and far western SD.