Aikyam-Lab/Synoptic-Bench huggingface dataset:
Water vapor satellite shows drier air streaming in from the north along the back end of a upper level trough, currently located off the east coast. This trough will move northeast and behind it an upper level ridge will build into the region. Strong upper ridge will continue to be centered well west of the region, across the southern Plains, while a second ridge remains east of the upper trough axis, in the western Atlantic.
Upper high over the southern Plains today builds north into the central Plains through the mid-week with the upper jet displaced well north.
1012 AM CDT Mon Aug 23 2021 Building upper ridge over the plains will continue to be the main story for the afternoon, with heat continuing through much of the work week as mid level heights continue to rise. Rain/storm chances increase by the weekend, along with relatively cooler temps. Mid level heights continue to slowly rise from the south, as mid level ridge center over TX shifts up over the Red River Valley. Evidence of this drying could already be showing up in area obs, like KMLC whose dewpoint has dropped into the upper 60s from the low 70s.
1217 PM PDT Mon Aug 23 2021 Below average temperatures to continue for the next couple of days due to a trough pattern aloft. Warming temperatures for the middle and later portions this week as high pressure builds. Not much change in the flow pattern aloft today compared to yesterday as a trough remains in place. Southwesterly flow associated with this trough has helped the valley and desert stay below average temperature wise and has kept us dry.
214 PM EDT Mon Aug 23 2021 High pressure at the surface and aloft will provide quiet weather. High pressure and plenty of sunshine on Tuesday equals to hot afternoon temperatures reaching the mid 90s across the lowlands, ranging into the mid 70s over the highest elevations. With high dew points, heat indices could reach the lower to mid 90s across much of the lowlands, even the upper 90s in spots.
410 PM EDT Mon Aug 23 2021 The region will remain positioned between an inland trough and Atlantic high pressure. High pressure will build in mid-week and prevail through the weekend. Weak high pressure building from the west has limited convective coverage to far southeast GA this afternoon. Overnight, the presence of an upper trough just off the coast should trigger scattered to numerous showers and tstms over the coastal waters, occasionally drifting into coastal land areas. Tuesday: Atlantic high pressure will build into the region on Tuesday both aloft and at the surface. With high pressure as the prevailing feature convective initiation will be diurnally driven, mostly along the afternoon sea breeze.
An upper level ridge is in place over the region and will remain the focus for the areas weather through this week. For today, a few upper level short waves will move through the upper ridge and bring the potential for some showers or an isolated thunderstorm to areas mainly east of Highway 65 as early as late this morning and into this afternoon. This will work to bring warmer and moist air into the region with afternoon temperatures today into the lower to middle 90s.
Temps will get a bit warmer Tuesday as well with highs expected mainly in the 90s across the state. Latest guidance is hedging on a bit more westward push of the ridge for the weekend though have some differences on where the deeper moisture axis extends as the GFS could be a bit drier solution.
137 PM EDT Mon Aug 23 2021 Weak high pressure is sliding across the Lower Peninsula this afternoon. An elongation of the subtropical ridge across the central and eastern US will occur over the next couple of days, with the ridge expected to persist into the weekend. In fact, recent medium range model trends build the ridge over the ern US over the weekend, indicating a likely hot and humid last weekend of August. This will result in a drop in surface dewpoints (possibly down into the low 60s) this afternoon, causing in a lowering of the humidity.
Overnight lows will should be 1-2 degrees warmer on average across the region. Rain chances will remain very low with no boundaries present and increasing heights under the ridge expected.
/issued 207 PM CDT Mon Aug 23 2021/ The center of the upper level high pressure system centered over eastern Texas will expand westward over the next 24 hours. As the high continues to build westward, temperatures will be slightly warmer on Tuesday; to most people, it will feel hot.
Lows tonight should be a little cooler than last night across the mountain valleys with lows dipping into the mid to upper 30s for locations around Creede and Leadville.
723 PM EDT Mon Aug 23 2021 High pressure at the surface and aloft will provide quiet weather. High pressure and plenty of sunshine on Tuesday equals to hot afternoon temperatures reaching the mid 90s across the lowlands, ranging into the mid 70s over the highest elevations. With high dew points, heat indices could reach the lower to mid 90s across much of the lowlands, even the upper 90s in spots. Summer will continue to have firm control over the region for the short term period courtesy of an upper ridge situated across the central portion of the country.
602 PM CDT Mon Aug 23 2021 Hot and humid conditions were occuring across the area this afternoon as the upper level ridge to the south slowly nudges towards the area. Afternoon highs or on track to reach the low to middle 90s. We will likely begin to see some mixing in the afternoon which will drop dewpoints some, however warmer temps will compensate with heat index values of 100-105 still expected.
Tomorrow, high pressure will continue to lose its hold on the region with slightly better coverage of showers and thunderstorms expected through the late afternoon. Have included PROB30 groups at all sites except BPT, where the high should still be strong enough to keep convection at bay for one more day.
High pressure will bring hotter temperatures the second half of the week. We continue to see troughiness through the region northwest of our area with a strong ridge building across southern tier states.
A cold front will work through the area on Tuesday, shifting winds to the northwest as it does. This cold front could trigger isolated storms across the far eastern CWA during the afternoon/evening, though confidence is low.
As a result, expect breezy southwest winds with slightly warmer temperatures. However, minor discrepancies in passing trough's amplitude and position/timing will result in varied QPF estimates through end of period.
(Previous Discussion) A mid-upper level low/trough will approach the area from the east as it moves W/NW over the Bahamas, which will nudge trough over the eastern U. Ridge axis as the surface will also gradually shift northward across the area with low level winds becoming S/SE. Highs will reach the low 90s.
Below average temperatures to continue for the next couple of days due to a trough pattern aloft. Warming temperatures for the middle and later portions this week as high pressure builds. Not much change in the flow pattern aloft today compared to yesterday as a trough remains in place. Southwesterly flow associated with this trough has helped the valley and desert stay below average temperature wise and has kept us dry.
1031 PM EDT Mon Aug 23 2021 Currently - The Atlantic ridge extends southwestward towards The Bahamas and Florida then westward into the Gulf of Mexico. This evenings sounding from both Miami and Key West indicated a layer of steep lapse rates and drier air in the mid levels and Miami's sounding indicated drier air and some inhibition through the lower levels as well. Short Term Update - The ridge across Florida will continue to build through the overnight period and east to southeast breezes are expected to freshen across our area. A ridge across Florida will strengthen overnight.
547 PM MDT Mon Aug 23 2021 Satellite imagery shows an upper trough across southern British Columbia and Alberta provinces.
A few more of the CAMs runs have the first scenario, but still a few are showing some impressive updraft helicity values developing across our eastern counties as a cold front pushes into the region. The cold front will push the rest of the way through the CWA Tuesday night and any convection that does redevelop will be shunted off to the east by midnight. While there are the usual subtle variations within the cluster analyses, overall good agreement exists on a trough digging in over the Pacific Northwest and continuing to induce southwesterly flow and surface systems over the northern and Central High Plains. For tonight, a cold front pushes into the area from west to east.
A warm front to our south from northeastern Montana to southeastern South Dakota will begin to move northward and develop elevated convection over eastern Dakotas. As the warm front moves northward, this will set up the southern portion of our CWA in a waa regime with strong theta-e north of the warm front along with an EML above 700mb.
1039 PM EDT Mon Aug 23 2021 High pressure over the Ohio Valley will build east into Pennsylvania Tuesday, then pass off the east coast during the middle of the week.
717 PM EDT Mon Aug 23 2021 High pressure builds across the area through the end of the week. Kept isltd PoPs in this eve across nrn zones as some of the high res data suggests this psblty over the next few hrs. Otherwise, skies will average mostly sunny with afternoon temps warming quickly into the low and mid 90s.
Expect morning lows in the low to middle 70s, warmest along and west of the Mississippi River.
627 PM CDT Mon Aug 23 2021 Should be a quiet night as very limited attempts at shower development west of KLBB and KPVW have failed and thunderstorms on the high terrain of central New Mexico are likely to dissipated on the plains of eastern New Mexico. /issued 207 PM CDT Mon Aug 23 2021/ The center of the upper level high pressure system centered over eastern Texas will expand westward over the next 24 hours. As the high continues to build westward, temperatures will be slightly warmer on Tuesday; to most people, it will feel hot.
901 PM EDT Mon Aug 23 2021 High pressure over the Ohio Valley will build east into Pennsylvania Tuesday, then pass off the east coast during the middle of the week.
907 PM EDT Mon Aug 23 2021 High pressure will gradually build in from the west through tonight, then shift offshore through much of the rest of the week. A cold front will approach from the northwest late in the week. The cells in SW PA have been stabilizing/dissipating for the most part as they enter the higher terrain with a more stable environment surrounding it. Given lingering low-level moisture, a clearing sky, and a light wind overnight, some dense fog may develop especially in sheltered river valley locations near and west of the Blue Ridge.
Afternoon highs will run 10 to as much as 15 degrees above average, especially over the favored downslope regions in the high plains.
No convection is expected near the CWA through the period with the subsident upper ridge in full control.
The upper-level ridge of high pressure will amplify over the Deep South, with hot and humid conditions prevailing both days. Abundant sunshine and southerly flow will help to push high temperatures into the low to mid 90s.
655 PM EDT Mon Aug 23 2021 Building high pressure will provide dry weather on Tuesday, with warm conditions persisting through much of the week. Otherwise, a warm and quiet night is on deck for the Upper Ohio Valley as the area remains on the north side of high pressure.
The mid level ridge currently taking hold across the southern plains will continue to bring mostly clear skies through tomorrow morning. Protected areas within valleys will likely be a few degrees cooler tonight.
Tuesday is looking sultry as highs average in the mid 90s (F) with dew points in the lower 70s / some locations mixing into the upper 60s. Aloft, forecast soundings show a deep swath of dry air and subsidence due to a H5 ridge spanning the southern CONUS.
Ensemble models continue to indicate that a weak trough axis will remain situated just off of the CA coast early this week.
1014 PM EDT Mon Aug 23 2021 The region will remain positioned between an inland trough and Atlantic high pressure. High pressure will build in mid-week and prevail through the weekend. Tuesday: Atlantic high pressure will build into the region on Tuesday both aloft and at the surface. With high pressure as the prevailing feature convective initiation will be diurnally driven, mostly along the afternoon sea breeze.
CD Chattanooga Airport, TN 71 94 73 93 72 / 0 10 0 30 10 Knoxville McGhee Tyson Airport, TN 70 94 71 93 71 / 0 10 0 30 10 Oak Ridge, TN 69 93 71 93 70 / 0 0 0 30 10 Tri Cities Airport, TN 66 93 68 93 67 / 0 10 0 30 10.
801 PM MDT Mon Aug 23 2021 Short term (tonight through Tuesday night) A cold front will move through the area tonight.
VFR conditions will prevail through the TAF period as high pressure strengthens over the region.
759 PM EDT Mon Aug 23 2021 High pressure over the Ohio Valley will build east into Pennsylvania Tuesday, then pass off the east coast during the middle of the week.
Tranquil conditions this afternoon across the region, with high pressure in control of the weather. The upper-level ridge of high pressure will amplify over the Deep South, with hot and humid conditions prevailing both days. Abundant sunshine and southerly flow will help to push high temperatures into the low to mid 90s.
Upper high located over the Arklatex this afternoon with positive ridging extending eastward toward TN. The west to east ridge will get a little more pronounced on Tuesday.
559 PM EDT Mon Aug 23 2021 Building high pressure will provide dry weather on Tuesday, with warm conditions persisting through much of the week. Otherwise, a warm and quiet night is on deck for the Upper Ohio Valley as the area remains on the north side of high pressure.
Water vapor imagery continues to show the deep plume of drier air diving to our west along the backside of the trough. A subsequent low level moisture gradient is also present at the surface, with dew points in the mid-upper 60s across the Upstate and in the low- mid 70s across the Midlands. Strong upper ridge will continue to be centered well west of the region, across the southern Plains, while a second ridge remains east of the upper trough axis, in the western Atlantic.
LCL heights likely on the higher end of preferred values for a more bonafide tornado threat but the presence of a boundary, strongly backed surface winds, and curvature of the low level hodograph make this threat non-negligible.
Ridge aloft also will reinforce dry conditions as well as heat. We are starting the early morning with some upper clouds as a weak wave moves within that ridge aloft.
406 AM EDT Tue Aug 24 2021 The main player in the forecast today will be an upper-level ridge centered over TX and OK, extending eastward to the southern Appalachians. Over the last day or so, this area of high pressure has led to weak subsidence and mid-/upper-level drying over much of the CWA. Highs today will be on par with highs yesterday -- in the lower to mid-90s. The ridge loses its grip over the forecast area on Wednesday as an inverted trough/vort max traverses the CWA from east to west.
Winds on Wednesday should have at least somewhat of an easterly component, so a cooler day is likely.
The remnants of Henri, phasing with an upper low, continue to rotate across eastern NY state, with bands of scattered convection extending into the western Finger Lakes/Twin Tiers, and more isolated showers and rumbles of thunder across the Catskills. Showers taper off into the night with the loss of daytime heating and a ridge beginning to build in. Another warm and humid day is expected Tuesday, with highs well into the 80s in our urban spots and typically warmer valleys yielding heat indices in the upper 80s and even near the 90F mark.
Afternoon highs will run 10 to as much as 15 degrees above average, especially over the favored downslope regions in the high plains. Still watching the potential for more robust convection on Wednesday afternoon as an upslope surface flow regime brings moisture back to the high plains. If the cap is breached however, multicell to supercell storm modes could be supported given favorable long hodographs with some curvature in the low/mid levels.
Limit time outdoors and drink plenty of water as the heat builds this week! High pressure centered over the Ohio River Valley will remain in control of the weather across central Illinois today. Given continued southerly flow and a good deal of sunshine, high temperatures will be a couple of degrees warmer than yesterday in the lower to middle 90s. Warm/muggy weather will continue into tonight as lows only drop into the lower to middle 70s. As an upper low evident on latest water vapor imagery over Alberta/Saskatchewan tracks eastward along the U. /Canada border, it will flatten the prevailing ridge over the Great Lakes and push a cold front into northern Illinois on Wednesday.
Short wave energy riding over the high will move into the northern plains, sparking development of thunderstorm complexes. These storms will move southeast over the downstream side of the ridge and dissipate in the vicinity of the Great Lakes states. Though instability is moderate in the Ohio Valley, placement east of the ridge leads to light flow and the lack of a trigger. Only change moving into tonight and Wednesday is the ridge- riding short wave continues its slow trek to the east, reaching the upper Midwest by Wednesday afternoon. This maintains ridging over the Ohio Valley, but the closer proximity of the trough allows a few more storms to reach the northern CWA during this period. A large mid level ridge will extend from the Central Plains through the Ohio Valley at mid week.
306 AM CDT Tue Aug 24 2021 The upper level ridge remains in place and will continue to allow for mostly sunny skies and warm temperatures in the middle 90s across the region again today. Some mixing is expected by late this afternoon but warmer temperatures that yesterday will keep heat indexes similar with a heat advisory remaining in effect today.
A cold front will work through the area on Tuesday, shifting winds to the northwest as it does. This cold front could trigger isolated storms across the far eastern CWA during the afternoon/evening, though confidence is low. Cooler air moves in behind the front, with lows in the mid 50s into Wednesday morning.
920 PM PDT Mon Aug 23 2021 Low clouds will continue the next few nights, but become increasingly shallower and confined to coastal areas as high pressure to the east slowly expands.
The ridge will continue to shift east that will lead to veering of low-level flow, which will transport drier air into the area.
An area of low pressure was located over British Columbia with weak troughing over northeast Washington. Weak ridging moves in overnight and into Tuesday before a trough off the Pacific Northwest coast moves onshore Wednesday into Wednesday night. Most areas will be in the low to mid 40s with the mountains in the 30s, and some mountain locations close to or below freezing. Temperatures on Tuesday will be warmer than today, as the ridging moves in, and many locations, will be close to 80 degrees, with the Basin in the low to mid 80s. Temperatures on Wednesday will be a degree or two warmer than on Tuesday.
With high pressure dominating the region, very light flow and low level moisture will likely yield valley fog overnight. Temperatures are forecast to be a couple of degrees warmer that both the previous day and previous night. For the beginning of the period, an extensive mid-level ridge stretching from the Southern Plains through the Ohio Valley will govern the weather.
The upper-level ridge of high pressure will amplify over the Deep South, with hot and humid conditions prevailing both days. Abundant sunshine and southerly flow will help to push high temperatures into the low to mid 90s. Combined with dewpoints in the low to mid 70s, heat index values will easily peak in the 100 to 105 degree range, and possibly exceed Advisory criteria, especially across portions of northwest and north central Alabama on Wednesday.
Offshore trough will continue promoting onshore winds again today.
338 AM EDT Tue Aug 24 2021 High pressure at the surface and aloft will provide quiet weather today. High pressure building surface and aloft spells a hot late summer day today after the morning fog burns off. Central guidance maintains lowland highs in the lower to mid 90s on h85 temperatures just below 20C below a slight inversion near or just above that level. Showers and storms can be expected Wednesday, particularly across the higher terrain during peak heating hours. Hot and humid conditions will continue across the area, with heat indices touching the lower 100s in spots.
Isolated showers and thunderstorms possible across the higher elevations of the mountains. Upper ridge with 500mb heights 590 to 592 dam will continue to influence our weather with mostly dry weather and mostly clear sky conditions. Temperatures remain warm in the low 90s and heat indices in the upper 90s across the southern Tennessee Valley this afternoon. A few isolated showers or thunderstorms will be possible across the higher elevations of the mountains, but coverage will be limited. Any afternoon convection across the higher elevations will dissipate tonight with the loss of daytime heating.
234 AM CDT Tue Aug 24 2021 With an upper ridge firmly in place, another dry very warm day expected today, and temps will remain very warm on Wed as well. On Wed however, our upper ridge will weaken a bit and that will allow some moderate moisture to creep into parts of our east/south. While the upper ridge does go through several variations into the weekend, it will remain the dominant feature aloft, as does high pressure at the SFC.
143 AM MDT Tue Aug 24 2021 Surface cold front has passed through Miles City and Sheridan, and will reach the Dakotas border in the next 1-2 hours. All of this energy will shift to the east today, leaving us in a dry zonal flow with a cooler and more stable air mass behind the cold front.
Last evening's upper air analysis and this morning's water vapor satellite imagery show the subtropical ridge over Texas. A warm, moist airmass remains in place with temperatures ranging from the middle 70s to the lower 80s. There continues to be good model agreement for the subtropical ridge remaining in place through the short term period. Models are also in good agreement in the lower levels with southerly to southeasterly flow continuing. The upper ridge will continue to suppress convection today. Temperatures will be about the same as the last couple of days, perhaps a degree or two warmer.
Some moisture increase expected this afternoon, mainly south and east, as an approaching upper low, traversing clockwise around an offshore upper high, moves NW towards the SE coast. The moisture from this wave and the weakness between upper ridges over Bermuda and the Central U.
246 AM EDT Tue Aug 24 2021 High pressure at the surface and aloft will provide quiet weather Tuesday. High pressure and plenty of sunshine on Tuesday equals to hot afternoon temperatures reaching the mid 90s across the lowlands, ranging into the mid 70s over the highest elevations. With high dew points, heat indices could reach the lower to mid 90s across much of the lowlands, even the upper 90s in spots. Showers and storms can be expected Wednesday, particularly across the higher terrain during peak heating hours. Hot and humid conditions will continue across the area, with heat indices touching the lower 100s in spots.
149 AM EDT Tue Aug 24 2021 A trough of low pressure will remain inland through Wednesday before giving way to Atlantic high pressure build into the area through the weekend.
Trimmed a few degrees off the lows for the usual cool spots for tonight as lows should drop below our blended guidance values as they did last night. Winds have been gusting 30-35 mph over and downwind of the higher terrain; and a few showers and thunderstorms have developed near the New Mexico border.