Aikyam-Lab/Synoptic-Bench huggingface dataset:
1136 AM PDT Mon Jun 28 2021 Triple digit heat is expected through the week with Tuesday likely the hottest day with some areas 110 degrees or warmer. As of 11AM, temperatures are running 3 to 5 degrees warmer than they were at the same time yesterday. /GKoch 18Z TAFS: Extremely strong high pressure will produce temperatures well into the triple digits this afternoon with places like Moses Lake, Omak, Wenatchee, Chelan, and Lewiston in the 110 to 115 degree range between 20-02z.
1232 PM CDT Mon Jun 28 2021 Active weather will continue through this evening as an upper level trough continues to impact the central Plains. This high will keep conditions dry through Tuesday.
Bermuda high pressure still maintains influence on the coastal Carolinas, creating only a chance of showers and storms for the next few days. An approaching cold front will bring more robust rain and thunderstorm chances by the weekend. On Tuesday high pressure at both the surface and aloft will be just offshore promoting a deep layer of SE to E winds. And while a few lightning strikes are usually very tough to rule out in late June shallow convection appears much more likely than deep on account of the suppressing action of the ridging aloft.
An omega block remains in place over the western CONUS with an upper trough positioned over the central CONUS and corresponding southwest flow over the Midwest states. SPC mesoanalysis has an area of 2000+ J/kg of MLCAPE draped over this same region, though the better shear is located across northwest counties near the IL River valley and northward, nearest to the upper trough. The omega block starts to break down later tonight into Tuesday as a kicker trough approaching the Pacific NW moves onshore, sending the large ridge eastward.
1234 PM CDT Mon Jun 28 2021 Afternoon showers and thunderstorms began developing around 17Z, with most of the activity now set up from around Mission Ridge to Onida and Faulkton and up through Houghton/Britton. Strong upper high over southwest Canada changes little through Tuesday, but overhead trof does start to fill as heights rise across the Northern Plains. However, mid level winds are a bit enhanced today (30-35 knots H500) across southern Minnesota ahead of the upper trof, so, a pulse strong/severe storm can't be ruled out over that area, mainly east of the ABR CWA.
Overnight lows in the lower 70s look good based on dew points. Looks as though the pattern may finally begin to slowly shift late tomorrow into tomorrow night as the ridge begins to retreat and modest height falls begin across the area. An upper level trough will move into the area through the end of the week.
Once this system moves west of the area on Tuesday, strengthening upper ridge north of the region will still keep an easterly flow pattern moving across the forecast area through the mid-week. By the end of the week, a digging upper trough moving through the Great Lakes will push the ridge back to the east. Otherwise, expect bands of showers and some thunderstorms associated with the cyclone, concentrated over the S Midlands and CSRA close to the track of the cyclone, where some locally heavy rainfall will be possible.
The weakening upper trough/low and copious moisture will contribute to continued scattered convection this evening/early tonight. Deterministic runs predict a weak upper ridge to begin building over the CWA from the E/NE Tuesday.
Afternoon convection has moved out of the lower RGV, leaving the TAF sites with VFR conditions. Guidance is showing lower, MVFR ceilings in conjunction with the higher rain chances on Tuesday. /issued 258 PM CDT Mon Jun 28 2021/ SHORT TERM (Now through Tuesday Night): The 500mb low and weak mid level inverted trough will continue to work southwestward across Deep South Texas into this evening. At the surface, a weak trough develops along the lower Texas coast through Tuesday night.
656 PM CDT Mon Jun 28 2021 As of this afternoon, high pressure has worked its way to just east of the Plains, and is expected to be widespread by this evening. At upper levels, high pressure resides over the east coast and the PACNW, where it is starting to move ENE. In between the 2 systems, broad troughing hangs across the middle CONUS from Ontario to NM or so. These are diurnally driven, with some FGEN in the broad trough axis and steep LL lapse rates aiding in formation. As such, overnight lows will be in the low to mid 50s across the region. For tomorrow, winds will shift to be southeasterly as the high moves to the east some. So, fcst highs are in the lower 80s. Behind this high pressure system, low pressure builds in over the Rockies.
Once this system moves west of the area on Tuesday, strengthening upper ridge north of the region will still keep an easterly flow pattern moving across the forecast area through the mid-week. By the end of the week, a digging upper trough moving through the Great Lakes will push the ridge back to the east. Otherwise, expect showers and some thunderstorms associated with the cyclone, mainly over portions of the CSRA.
Slightly rain-cooled air has altered temperature trends slightly, bringing the overnight low further down into the lower 70s, while dew points also remain in the low 70s, maintaining muggy conditions.
Atlantic high pressure will then prevail before a cold front approaches the region late week. Latest KCLX detected a band of moderate to heavy rain pivoting over the lower Savannah River.
Otw, the current dewpoints, which are generally in the lower 70s, should support are fcst lows in the upper 60s to lower 70s. Strong mid/upper level high over the mid Atlantic states is helping to provide the northwesterly storm motion.
628 PM CDT Mon Jun 28 2021 GOES-16 water vapor imagery this afternoon showing a highly amplified pattern in place with stationary ridges of high pressure anchored on both coasts and a deep trough of low pressure over the central CONUS. Impressive tropical tap (atmospheric river) from the eastern Pacific/Gulf of Mexico ahead of the trough was keeping rather humid airmass in place across our forecast area through Tuesday with precipitable water values hovering in the 1. Will see widely scattered showers and isolated storms this afternoon into this evening with more coverage expected Tuesday as that trough oozes ever so slowly eastward across the area. Strong Pacific Northwest ridge begins to slowly weaken heading into mid-week.
557 PM MDT Mon Jun 28 2021 Cooler than average temperatures each day along with a possibility of isolated to scattered showers and thunderstorms will continue through mid-week.
/00Z TAFS/ A few weak convective cells are temporarily forming to the distant SE of SAT/SSF, but no impacts are expected for the rest of the evening at the TAF sites given the cooler downstream temps over Bexar County. These showers, associated with an upper low that is moving across south Texas into Mexico, should start to decrease in coverage tonight. The deep moisture behind this low is still abundant and some light, lingering showers may persist overnight. The overall pattern shows little change, and the moist tropical airmass in place, along with the development of a coastal trough, should result in continued chances for showers and thunderstorms through Tuesday.
Temperature will be cooler than average thanks to storms and cloud cover. Water vapor imagery showed upper level trof/weak upper low over SW NM. That upper level trof/weak upper low will be a player in our forecast for the next several days.
/CME/ Prior discussion below: Tonight and tomorrow: A flat upper ridge extending from the Atlantic Coast into the Lower Mississippi Valley will remain in place through the period. For tomorrow, an inverted trough associated with the remnants of Tropical Storm Danny is forecast to slide into the area from the east and will help instigate scattered afternoon showers and storms.
846 PM EDT Mon Jun 28 2021 An anomalous upper level ridge will remain centered off of the Mid Atlantic coast through the middle of this week.
Considering that the main portion of the high pressure responsible for the current heatwave across the western US is located east of the Northern Rockies, easterly winds will continue to be present through midweek as well.
Mild temps tonight due to cloud cover and southerly flow with lows in the low to middle 60s. Tuesday Night Through Monday A 500mb trough is expected to dig and then close off across the eastern third of the United States by late in the work week. The GFS was further to the west with the closing off of the upper low.
515 PM MDT Mon Jun 28 2021 Iso SHRA/TSRA continue this aftn near a trof axis slowly shifting sewd thru the n cntrl CONUS. Primary trof axis shifts ewd into the Upper Midwest tonight into early tomorrow. Low- level thermal ridging will slowly expand ewd into the High Plains as mid-to-upper ridge progresses ewd. Main fcst question over the latter half of the work week will be whether or not troughing over the ern CONUS can chip away at the ern periphery of the ridge sufficiently to support lift for showers/storms across our region.
However, satellite imagery indicates some cumulus clouds starting to pop up over the higher terrain of the Sierra this afternoon.
Upper level ridge will continue the heat wave for the Northern Rockies through the week. Temperatures will be a few degrees warmer tomorrow over today for temperatures between 104-108 in the lower valleys.
Temperature trends this evening have actually been a little warmer than previous fcst, thus blended in latest (warmer) ConsShort through the overnight hours. CDG Chattanooga Airport, TN 72 87 71 90 71 / 10 60 30 60 20 Knoxville McGhee Tyson Airport, TN 70 90 71 90 71 / 10 50 20 60 30 Oak Ridge, TN 70 90 69 89 69 / 20 40 20 60 30 Tri Cities Airport, TN 65 91 67 90 67 / 10 20 10 50 30.
The surface analysis also depicts a broad subtropical ridge centered over the western Atlantic and extends all the way to the eastern Gulf of Mexico and the eastern United States. The Florida Keys are in the southwestern periphery of the ridge, resulting in moderate east to southeast breezes. Temperatures in the island communities are near 80 degrees Fahrenheit to the lower 80s. From synopsis, high pressure centered over the western North Atlantic will maintain moderate east to southeast breezes through the next few days. Breezes will diminish for the second half of the week as the high weakens and sags southward across Florida.
This activity was not well-resolved by the CAMs, save perhaps for the HighRes ARW ETA, which depicted this cluster north into middle TN. Satellite shows a widespread Cu field over the entire area, with the quasi-stationary front still draped from TX through OK, MO and into the lower Great Lakes. Temperatures will cool off into the low to mid 70s overnight. A low pressure system sits off the mid California coast, blocked by an intense high pressure system that is sitting over the Pacific Northwest and Southwestern Canada giving them record breaking temperatures and heat indices. A low pressure system is located in southeastern Canada and near the Great Lakes.
Subtle 500mb height falls arrive overnight ahead of a slow-moving upper trof in MN. Deep layer SW flow remains across the western Great Lakes with a fairly narrow corridor of deep moisture (PWAT> 2 inches) extending from the Texas Gulf coast up into the lower Great Lakes. At the surface, a weak area of high pressure lingers across Lower Michigan. Overall forecast confidence with precip chances and placement remain on the low side with varying model solutions that change with each run. Thus, plan is to have the higher precip chances/QPF across the southern and eastern portion of the CWA, with eastern Upper Michigan remaining dry tonight. A surface warm front draped across northern Michigan in combination with daytime heating and moisture in place (precipitable waters 1.
539 PM MDT Mon Jun 28 2021 The forecast was saddled between the unusually strong high pressure system over the Pacific Northwest and an elongated mid- level low pressure trough extending southwestward from the northern Plains to the southern High Plains. Showers have developed over the higher elevations of the Sawatch and San Juans early this afternoon, and expect lightning will pick up as afternoon wears on. The trough over the southern Plains retreats northeastward later tonight allowing the high over the southeastern US to expand westward causing a shift in flow to the south for much of the area on Tuesday.
600 PM MDT Mon Jun 28 2021 00Z TAF CYCLE A longwave trough continues to extend from Ontario, Canada toward the southern Rockies with a weak low pressure circulation trying to take shape over New Mexico.
/CME/ Tonight and tomorrow: A flat upper ridge extending from the Atlantic Coast into the Lower Mississippi Valley will remain in place through the period. For tomorrow, an inverted trough associated with the remnants of Tropical Storm Danny is forecast to slide into the area from the east and will help instigate scattered afternoon showers and storms.
Atlantic high pressure will then prevail before a cold front approaches the region late week. Lows should generally be in the lower to mid 70s inland and mid to upper 70s at the coast.
524 PM EDT Mon Jun 28 2021 An anomalous upper level ridge will remain centered off of the Mid Atlantic coast through the middle of this week.
317 PM MDT Mon Jun 28 2021 Cooler than average temperatures each day along with a possibility of isolated to scattered showers and thunderstorms will continue through mid-week.
840 PM EDT Mon Jun 28 2021 An anomalous upper level ridge will remain centered off of the Mid Atlantic coast through the middle of this week.
A weak area of low pressure will pull moisture northward across southern Utah Tuesday.
915 PM EDT Mon Jun 28 2021 Offshore Bermuda high pressure will remain in control through the middle of the week.
With the mid-level ridging a bit more stout over the region, today's convective activity has been modest at best.
Temperatures are similar or slightly warmer compared to 24 hours ago, aided by the northward departure of the offshore upper low. The marine layer is somewhat deeper at Bodega Bay (~1500 ft), closer to the upper low. Tomorrow will be the warmest day of the week, as we won't be under the influence of the offshore low, and the record-breaking high pressure system over the interior NW noses slightly into NE CA.
524 PM MDT Mon Jun 28 2021 IR/WV satellite review showed the large scale omega block pattern with the heat ridge centered over the Pacific Northwest and upper trough axis over the northern and central Plains. Temperatures will moderate 3-5 degrees with highs in the lower 70s to lower 80s.
High pressure over the Pacific Northwest will keep skies mostly clear with periods of light easterly winds.
Considerable debris cloud cover from earlier convection will diminish after midnight, with skies becoming partly cloudy and temperatures falling into the low to mid 70s.
The upper pattern across the CONUS remains stagnant with ridges located over the east and west coasts and a trough over the center of the country. Perturbations continue to round the base of the trough with showers and storms present along the 850mb front that extends from central Texas and Oklahoma into southeast Kansas and western Missouri.
An approaching cold front late week will bring increasing thunderstorms chances this weekend. On Tuesday high pressure at both the surface and aloft will be just offshore promoting a deep layer of SE to E winds. And while a few lightning strikes are usually very tough to rule out in late June shallow convection appears much more likely than deep on account of the suppressing action of the ridging aloft.
The southern portion of a persistent upper trough over the Midwest and central High Plains was beginning to weaken and lift northward.
445 AM EDT Tue Jun 29 2021 08Z sfc analysis shows high pressure to the east of Kentucky with the remains of T. More clouds around this night has kept temperatures from dropping off much resulting in only a small ridge to valley temperature difference.
The upper pattern across the CONUS remains stagnant with ridges located over the east and west coasts and a trough over the center of the country. Perturbations continue to round the base of the trough with showers and storms present along the 850mb front that extends from central Texas and Oklahoma into southeast Kansas and western Missouri. The pattern finally begins to progress as the eastern ridge builds into the southern Plains and the trough is shunted northeast into the Great Lakes region.
Tuesday and Wednesday: A mid-level trough presently from the central High Plains into upper MS Valley is forecast to weaken while becoming absorbed into a broader trough evolving over eastern Canada.
Temperatures will continue to be warmer by a few degrees each day. Afternoon highs will be in the upper 80s to lower 90s today with 90s across the lower elevations for Wednesday.
121 AM MDT Tue Jun 29 2021 Upper level analysis shows upper trough axis in roughly the same position as this time yesterday - centered from western MN southwestward into eastern SD and central NE. Fairly quiescent weather today as upper trough elongates and pivots eastward. Deep upper ridge continues to nose eastward and when coupled with weak warm air advection and diabatic heating, will result in a warmer day today than previous days with highs in the 80s across the area today along with sunny skies. Upper ridge will dominate the synoptic pattern the rest of the week as southerly flow continues to advect warmer air into the region.
BRO radar currently indicates some showers and thunderstorms well south of the Rio Grande Valley and off the lower Texas coast. Afternoon convection has moved out of the lower RGV, leaving the TAF sites with VFR conditions. Guidance is showing lower, MVFR ceilings in conjunction with the higher rain chances on Tuesday. /issued 258 PM CDT Mon Jun 28 2021/ SHORT TERM (Now through Tuesday Night): The 500mb low and weak mid level inverted trough will continue to work southwestward across Deep South Texas into this evening. At the surface, a weak trough develops along the lower Texas coast through Tuesday night.
The forecast period begins with a trough extending from the Salt Lake City area into the Tri-State region. Southwest flow aloft persists over the region today with high pressure centered over southern British Columbia and northern Washington and Idaho. A ridge remains in place over British Columbia and Alberta. Wednesday, high pressure is in place over the south. At the start of the period, an upper trough continues across eastern Canada into the Great Lakes. In addition, an area of high pressure is located over the southern Plains, with ridging over portions of the western CONUS.
Subtle 500mb height falls arrive overnight ahead of a slow-moving upper trof in MN. Deep layer SW flow remains across the western Great Lakes with a fairly narrow corridor of deep moisture (PWAT> 2 inches) extending from the Texas Gulf coast up into the lower Great Lakes. At the surface, a weak area of high pressure lingers across Lower Michigan. Overall forecast confidence with precip chances and placement remain on the low side with varying model solutions that change with each run. Thus, plan is to have the higher precip chances/QPF across the southern and eastern portion of the CWA, with eastern Upper Michigan remaining dry tonight. A surface warm front draped across northern Michigan in combination with daytime heating and moisture in place (precipitable waters 1. Highs both days ranging from the muggy mid 70s north to the low 80s south.
Atlantic high pressure will then prevail before a cold front approaches the region late week. Tonight: Tropical Depression Danny will continue to track inland of the area in a weakening state, while high pressure centered across the western Atlantic begins to spread across the region through daybreak. Clouds across the area could help maintain more mild temps, with lows generally dipping into the low-mid 70s.
Temperature trends this evening have actually been a little warmer than previous fcst, thus blended in latest (warmer) ConsShort through the overnight hours. LW Chattanooga Airport, TN 87 71 90 71 88 / 60 30 60 20 70 Knoxville McGhee Tyson Airport, TN 90 71 90 71 89 / 50 20 60 30 80 Oak Ridge, TN 90 69 89 69 87 / 40 20 60 30 80 Tri Cities Airport, TN 91 67 90 67 87 / 20 10 50 30 80.
The majority of the high resolution models are in fairly good agreement with this timing, with most of the precipitation dissipating or moving north of our area by the Tuesday evening hours. The high precipitable water values continue into Wednesday, but synoptic models show high pressure forming across north Texas.
Water vapor imagery shows upper low situated over nw Mexico early this morning. 4" values across SE Tx and surface obs show a well defined area of speed convergence along a weak trof at the coast. 1") and weak mid level ridging builds in from the ne.
Otherwise, seasonably mild temps are expected into the overnight hrs, as lows fall mainly into the lower 70s/near 70F. Low level moisture also spreading nwd around the ern periphery of the ridge pattern over the srn Atlantic may also allow for a few light showers heading into the early morning hrs Tue.
Another hot and humid day is expected as broad high pressure remains over the eastern CONUS and surface dewpoints remain in the upper 60s/lower 70s. Wednesday will see greater shower and thunderstorm coverage with falling heights ahead of an approaching upper trough.
High temperatures will be considerably cooler than normal through Wednesday before a slow warming trend develops as high pressure aloft moves back toward the Four Corners region, but will remain below normal for most locales. As the omega blocking pattern persists across the PacNW, and an upper high over the east coast, the elongated trough over NM is not expected to move significantly over the next 36 hours.
Mesoanalysis data indicated a withering zone of pos tilted troughing over the Nrn Great Plains, w/ ridging remaining over the Wrn and S/Ern CONUS. Through the remainder of the fcst PD, the remains of the aforementioned upper trof wl be pushed N/wrd into Canada as Ern US upper ridging retrogrades, shifting high pressure to become more centered over the FA by midweek.
Meanwhile, an upper level low centered just south of the Florida panhandle will continue to move west and also weaken today. At the surface, the axis of the western extension of the Bermuda ridge will remain north of our region. Highs today will be around 90 to the lower 90s with lows tonight in the lower 70s.
311 AM EDT Tue Jun 29 2021 We'll have another hot and muggy day today as temperatures lift into the lower and middle 90s once again.
The upper level flow continue to be from the southwest as the region resides on the western periphery of a upper level ridge over the eastern CONUS. This pattern will begin to change Wednesday as the upper level flow becomes more zonal in response to a upper level trough moving through the Great Lakes flattening the upper ridge across the eastern and southern CONUS.
With the additional moisture, models show PWAT values climbing to around and just above 2 inches, and that looks to linger through the week as the upper trough moves eastward off to our north during the week. We may have a break from showers and storms during overnight hours, but as the front approaches the region from the northwest, and the upper trough sits over the Great Lakes region, afternoon showers and thunderstorms will be more widespread Wednesday.
Given the high rainfall rates in any activity this afternoon and evening, flash flooding could develop quickly. As for temperatures, expect highs to range from the lower 80s across the northwestern portions of the CWA and middle to upper 80s for areas south and east of the Interstate 44 corridor. Temperatures will reach into the lower 80s.