Aikyam-Lab/Synoptic-Bench huggingface dataset:
On Wednesday, we'll see moisture gradually increase as the ridge axis shifts east and a weak cold front drops across the plains. A ridge of high pressure will keep a dry and subsident airmass over the forecast area tonight. On Wednesday, the ridge will shift slightly to the south and east, as a weak disturbance moves across WY/northern CO in the afternoon. A short wave trough passing to the north of Colorado will bring scattered showers and thunderstorms Wednesday evening.
640 PM CDT Tue May 26 2020 00Z TAFS Scattered showers and isolated thunderstorms have developed this evening in response to a weak upper level disturbance rotating around a broad upper low centered over northeast Texas. Various high res guidance has been showing a slight uptick in development through the evening with the passage of the next disturbance rounding the low before convection simmers down overnight and through tomorrow.
143 AM EDT Wed May 27 2020 Aviation - Isolated showers/storms today/Wednesday - Numerous showers/thunderstorms with the front Thursday - Summer-like temperatures today/Wednesday, cooler by the weekend - Isolated showers/storms today/Wednesday Diurnally driven scattered convection will continue through the early evening hours. A large upper level low will be moving through the south as High pressure is pushed into the northern Atlantic. A fairly tight gradient should form between those systems and a deepening upper level trough that will be moving Southern Canada and into the region.
High pressure will remain in place across the region through the rest of the week. An anticyclonic north to northwesterly flow aloft remains in place over Utah this evening downstream of a ridge over the West Coast and western Great Basin. Meanwhile, a subtle disturbance has flattened the upstream ridge, resulting in increased cloud cover across the forecast area along with some isolated high- based showers across northwest Utah. Owing to the moisture and flattening ridge, temperatures are only expected to warm slightly across the north tomorrow, with more substantial warming across the south.
This will send a couple cold fronts through the region. Ahead of the first cold front anticipate a thermal ridge across the region today with temperatures into the upper 70s and low 80s, along with breezy westerly winds. Cooler air will then filter into the region tonight with another round of strong cold air advection on Thursday (high temperature upper 60s/low 70s) and windy conditions again in the afternoon. Thu Night - Sun: Northwest flow aloft downstream of a building upper ridge over the Rockies will drive a colder and drier air mass into the area through the weekend, with the bulk of this air mass moving into the northern Great Lakes region.
This will send a weak cold front south to the Continental Divide by early afternoon. High temperatures will be about 5 degrees cooler over the east in wake of the cold front, but about 5 degrees warmer over the west and south today. On Thursday, upper ridging begins to build into the Rockies with mainly dry conditions.
Some areas of showers have been moving northwest this morning, along the eastern edge of the upper level closed low, currently over OK/AR. Support will come from the upper level low, surface heating, and convergent boundaries on the surface. The surface pattern will become more organized tomorrow morning, with a cold front taking shape in our northwestern counties before sunrise. The front, storms, and upper level low will exit our area Thursday night, ending the rain chances for a while.
Excessive heat continues tomorrow as upper level ridging persists.
245 AM CDT Wed May 27 2020 Water vapor imagery currently shows upper low centered over far northeast TX with a vort lobe stretching from eastern OK into LA. Upper low will start to move east tonight into Thu which will allow the better rainfall chances to also migrate east. Below normal temps will remain in place today with readings topping out in the low to mid 70s. Upper impulse will be situated over the Tennessee Valley by Fri afternoon with upper ridging building over the Desert Southwest. Upper ridging will slowly build east through the weekend providing dry conditions and warming temps. For the rest of the night, expect clouds to linger overhead as a cut-off upper low stalls over the southern Plains.
The culprit for all this continues to be an upper level low over Oklahoma that is cut off from the main flow. This low will remain nearly stationary over eastern Oklahoma tonight and Wednesday. With the clouds and precipitation not a lot of diurnal range in temperatures expected, with lows tonight in the low to mid 60s and highs Wednesday in the low to mid 70s. Wednesday night through Thursday the closed upper low slowly meanders from eastern Oklahoma into northern Arkansas. No expecting any severe weather as shear and instability profiles are weak given the proximity of the upper low and lots of clouds.
1050 PM MDT Tue May 26 2020 Cold front lays across northwestern Wyoming this afternoon.
An upper low over the southern Plains will continue to push toward the area through Wednesday. Closer proximity to the low means a continued theme of scattered showers and isolated thunderstorms.
In the upper levels, a closed low was centered close to western Arkansas. Over the course of the short term periods, the closed low will drift through the state, with showers and thunderstorms continuing. Some areas will remain prone to flash flooding concerns, as rain will be heavy at times, especially as bands lift northeastward ahead of the upper low and interact with the surface boundary.
214 AM EDT Wed May 27 2020 High pressure will ridge into the area from the east through this evening. Weak low pressure then moves northward from the Carolinas reaching western Pennsylvania Thursday morning. This low weakens as it moves off to the east through Thursday afternoon.
Seasonable temperatures are expected through Thursday, before a significantly warmer temperatures move into the region over the weekend. With pockets of cooler air aloft, a few passing light showers/thunderstorms will possible through Wednesday. Temperatures will be a touch cooler on Wednesday over the north as a result. Warmer/drier air starts to move into the region on Thursday, as an upper level ridge builds over the region.
Large scale subsidence will continue to spread into the area overnight on the back side of a slow moving upper level low. This upper low currently centered over North Texas will slide a bit farther to the east tomorrow. The Rolling Plains will generally be cool tomorrow in closer proximity to the upper low and expected mid level cloud cover. A weak short wave will be rotating around the low but will keep a bulk of the lift to the east of the FA. The slow-moving closed low will gradually weaken into an open wave and move east by the end of the week allowing a ridge to build across the area for the weekend. Temperatures won't get too out of control and will remain in the upper 80s to lower 90s under the ridge.
324 AM EDT Wed May 27 2020 Quiet, dry weather is expected today under high pressure. Rain chances return early tomorrow morning as a low pressure systems tracks north. High pressure will maintain dry, warm conditions today. An advancing trough over the Great Plains will help maintain quick northern progression of the wave through our region. Heaviest rainfall amounts will likely occur on the east side of the ridges due to sufficient up-sloping; 850mb winds will near 40kts. In the wake of the exiting low pressure system, isolated, diurnally- driven showers/storms may develop in eastern Ohio tomorrow evening.
This in an area of 8-9 deg C/KM low level lapse rates along that weak cold front. That weak cold front was draped across southeast Saskatchewan to near Glasgow, Montana, as of this writing. Tomorrow will be slightly cooler than today as northwesterly winds and cold air advection kick in behind the front. Cooler temperatures are expected on Thursday after the Canadian upper low moves off to the southeast and northwest flow sets up over North Dakota. A building ridge from the west will initiate a warming trend through the rest of the forecast period until the ridge axis moves over the northern Plains by late this weekend.
As of 06Z, temperatures ranged from the 50s and lower 60s across the western South Plains to the lower and middle 60s off the Caprock. A vorticity maximum rotating around the west side of the upper low could support a few sprinkle or very light showers across eastern zones today, though the better chances will off to the east and southeast of the FA. It will be a little cooler closer to the upper low as highs reach the middle 80s for most spots off the Caprock. The upper low will absorb into the main flow by tomorrow morning and push across the southeastern US.
Previous discussion: Strong upper jet coming into western Canada is expected to carve out a closed low over south-central Canada Wednesday that will put northeast Montana under a slight NW flow. This will allow cooler air to move in for Wednesday and Thursday with temps near normal. An upper ridge will then begin building over the northern Rockies while a trough digs along the West coast starting Thursday.
834 PM PDT Tue May 26 2020 Very little to change with the evening update/ High pressure ridge continues to build into the area, which will bring dry and increasingly warm weather for the next couple of days. Wind will continue to decrease and will be 10 kts or less into Wednesday as an area of high pressure builds in to the area over the next few days.
This is in response to the influence of the upper low over the southern Plains and a quasi-stationary surface boundary extending north to south near Highway 71 (parts of northwest Iowa and southwest Minnesota). Highs will range in the lower 80s west of I-29 and in the upper 70s east, which is where more clouds/very light rain will persist. The closed upper low over the southern Plains will finally move eastward on Thursday, as a broad ridge aloft over the western CONUS migrates eastward.
Low pressure over the southern plains is expected to push toward the Great Lakes over the next few days.
1045 PM CDT Tue May 26 2020 (This evening through Wednesday) Broad cut off upper low over the region will drift eastward.
Farther east, toward, HWY 63, clearer skies, have resulted in temperatures over five degrees (F) warmer and dew points approaching 70 F. 15z Surface analysis reveals the low center remains focused over the MO/KS border south of the KC Metro. Southeast surface winds will persist, with bufkit soundings suggesting rather uniform wind profiles through the low to mid levels. As the bowling ball 500mb trough churns over the ArkLaTex through Wednesday evening, rain chances will increase, especially across the eastern half of Missouri early and farther westward and into Iowa through early Thursday morning.
401 AM EDT Wed May 27 2020 Quiet, dry weather is expected today under high pressure. Rain chances return early tomorrow morning as a low pressure systems tracks north. High pressure will maintain dry, warm conditions today. Tonight, a fast moving low pressure system currently off the coast of South Carolina will track east of the Appalachians and become an open wave as it enters the Upper Ohio Valley. An advancing trough over the Great Plains will help maintain quick northern progression of the disturbance through our region. Heaviest rainfall amounts will likely occur on the east side of the ridges due to sufficient up-sloping; 850mb winds will near 40kts from the southeast. In the wake of the exiting low pressure system, isolated, diurnally- driven showers/storms may develop in eastern Ohio tomorrow evening.
As a low pressure and associated boundary drifts slowly northeast tonight, a better chance for widespread showers and thunderstorms will come to the area for Wednesday through Thursday.
We'll be keeping a close eye on an inverted trough beginning to form just southeast of the forecast area. Latest observations support this trough residing just east of Storm Lake, with model guidance indicating this front may stall along the far eastern tier of counties by mid-late afternoon. While the overall severe weather risks remains on the lower end, the greatest threat would come from a brief tornado and marginal hail. Wednesday: Wednesday again should remain dry as the forecast area remains stuck between in the weak flow between a stronger northern stream jet over the Canadian border and the upper low across Arkansas. Temperatures Thursday will climb into the lower 70s.
A ridge of high pressure will lift northward and expand across the Sunshine State for the balance of this week.
Upper low centered over the ArkLaTex will remain nearly stationary through the day with most of the showers and thunderstorms expected underneath and to the east of the feature today. A vort lobe rounding the upper low this afternoon and evening is forecast to spark showers and thunderstorms across South Central Texas late in the day and move into portions of the area this evening.
427 AM EDT Wed May 27 2020 Unsettled conditions expected through the end of the week with low pressure lifting into the area today followed by an upper trough crossing the area late in the week.
Model guidance has backed off on fog potential, most likely owing to cloud cover beneath the upper low. /Issued 856 PM CDT Tue May 26 2020/ Isolated showers continue across eastern Oklahoma and western Arkansas this evening as an upper level low centered over northeast Texas spins over the area.
1159 PM CDT Tue May 26 2020 Upper low drifting through the area will keep scattered showers/storms in the forecast, with convection more spotty during the overnight hours and more widespread diurnally. Diurnal convection wl ramp up again Wed as the upper low works into AR. Tonight Through Thursday Upper low pressure continues over Oklahoma and Kansas and will only slowly move east through Thursday. A cold front moved through the state this morning and is now stalled in eastern Arkansas and is where showers have initiated.
In the extended, the GFS and ECMWF show a 500 mb trough over the ern half of the U. 12z Sat with a ridge over the Rockies with a trough off the west coast. The upper pattern remains stationary through Sun and then the ridge moves out into the plains 12z Mon. The ridge then moves slowly east towards the upper Great Lakes 12z Tue. All three sites will be experiencing LLWS early this morning as the low level jet continues over the area. Passage of a stronger cold front later Thu will offer the potential of stronger winds in the Thu night into early Sat time frame. Fog, shifting with the prevailing winds, will continue to plague Lake Superior until the stronger cold front moves across the lake later Thu.
401 AM EDT Wed May 27 2020 Unsettled conditions expected through the end of the week with low pressure lifting into the area today followed by an upper trough crossing the area late in the week.
400 AM CDT Wed May 27 2020 An upper level trough is over the southcentral part of the country. The upper trough will move over the Mississippi River Valley on Thursday with a cold front coming into West Texas and southeast New Mexico. Chances of showers and thunderstorms increase Thursday afternoon mainly across the higher terrain.
316 AM EDT Wed May 27 2020 Synopsis/Discussion/Marine/Hydro - Thunderstorms possible today, more precipitation Thursday - Hot and humid today, cooler over the weekend -- Thunderstorms possible today, more precipitation Thursday -- Radar shows a cluster of showers/storms moving north across northern Indiana. An even higher chance of rain exists Thursday as showers/storms develop along/ahead of a cold front. -- Hot and humid today, cooler over the weekend -- High temperatures today will reach the mid 80s, a tad cooler than yesterday, mainly due to increased cloud cover during the afternoon.
Over the eastern CONUS a well amplified upper ridge prevailed. At the surface, and area of low pressure was situated over western IA.
Otherwise, conditions will be dry tonight, with overnight lows slightly cooler than usual late May lows.
353 AM CDT Wed May 27 2020 The 500mb cut-off low continues to circulate over the Southern Plains at 08Z this morning per water vapor imagery. Stratus on the north side of the low will likely linger in eastern KS overnight. Have trended on the lower side of guidance for PoPs, but at least maintained slight chances mainly over eastern areas through the day. Chances of showers increase toward the evening and overnight hours when the CWA ends up in the deformation zone as the low moves northeast. Highs will reach the low to mid 70s with overnight lows falling back to the low 60s across the area.
Upper low, currently spinning over E OK/TX will continue to slowly head northeastward through Thursday night, resulting in northerly flow aloft over the Panhandles.
235 AM CDT Wed May 27 2020 An upper level low pressure system remains over the Southern Plains this morning. The upper low will slowly move eastward over the next 48 hours and will be located over the Mid-South by Thursday morning. A lull may then occur for a couple of hours before convection begins developing as daytime heating interacts with the upper level low pressure system. The upper low is forecast to open up as an upper trof by Thursday evening.
1032 PM MDT Tue May 26 2020 19z surface analysis had weak high pressure over the CWA. Looking upstream, attention turns to trough over BC/AB. It will drag a cold front through the northern plains Wednesday.
Moving forward into the forecast period, the deep trough currently overhead is expected to pinch off tonight in its southern portions to form a closed low that will linger over the Ark-La-Tex region through Thursday. Ridging then begins to build into the area and usher the closed low back into the flow, leaving us with northwesterly flow for the weekend. This ridge is expected to move eastward slowly, meaning we could have relatively quiet weather for a even longer.
Models this morning remain in good agreement with an upper low over Oklahoma and north Texas slowly wobbling east towards Arkansas and Louisiana over the next 24 hours. As several upper waves rotate around this upper low and across south central Kansas today and again later tonight there will be an increase in clouds along with a chance for some high based light rain showers or sprinkles. Temperatures today will climb into the lower 80s across far southwest Kansas given these locations will have more sun than clouds.
(Today and tonight) As the upper level cyclone continues to slowly exit the region to the east, precipitation chances shift east as well. While upper air support persists with the broad upper level cyclone, any convection and precipitation continues to be stifled by both the thermodynamics and shear, with seasonably cool surface temperatures due to cloud cover, unfavorable mid level lapse rates, as well as very weak vertical wind shear profiles. The highest chance of precipitation is generally in southeastern Oklahoma where the greater instability is anticipated. The upper level forcing may be enough to cause some showers to develop on the back end of the upper level cyclone as it moves further east, however coverage will be limited by the poor environment.
720 AM EDT Wed May 27 2020 Aviation - Thunderstorms possible today, more precipitation Thursday - Hot and humid today, cooler over the weekend -- Thunderstorms possible today, more precipitation Thursday -- Radar shows a cluster of showers/storms moving north across northern Indiana. An even higher chance of rain exists Thursday as showers/storms develop along/ahead of a cold front. -- Hot and humid today, cooler over the weekend -- High temperatures today will reach the mid 80s, a tad cooler than yesterday, mainly due to increased cloud cover during the afternoon.
634 AM CDT Wed May 27 2020 Water vapor imagery currently shows upper low centered over far northeast TX with a vort lobe stretching from eastern OK into LA. Upper low will start to move east tonight into Thu which will allow the better rainfall chances to also migrate east. Below normal temps will remain in place today with readings topping out in the low to mid 70s. Upper impulse will be situated over the Tennessee Valley by Fri afternoon with upper ridging building over the Desert Southwest. Upper ridging will slowly build east through the weekend providing dry conditions and warming temps.
Upper low near the Arklatex will continue to move very slowly. However, a subtle trough axis extending southwest of the low, will lift north across western portions of the forecast area this afternoon into the evening.
High pressure building across the Great Basin will be briefly suppressed by a weak wave moving through northern Utah today.
240 AM PDT Wed May 27 2020 High pressure will continue hot weather with moderate to high heat risk through Thursday.
545 AM CDT Wed May 27 2020 Scattered showers and storms will continue today, as Low pressure inches closer to the Midwest. A slightly cooler day will be in store, as clouds increase today.
TRI will have the lowest chances with southeasterly downsloping flow and have left the TAF there dry. The upper level low to the west continues to make slow progress eastward tonight and there could be a few more showers move into CHA in the overnight hours. MA Chattanooga Airport, TN 76 67 82 65 82 / 50 50 70 50 60 Knoxville McGhee Tyson Airport, TN 78 64 82 65 82 / 50 40 60 40 70 Oak Ridge, TN 78 65 82 64 82 / 40 40 60 40 70 Tri Cities Airport, TN 76 60 83 62 81 / 20 20 50 30 70.
This upper level trough will deepen today and tonight supporting a cold front pushing through the state. Cold air advection will also result in slightly cooler temps today along with dryer air. For tonight, expect a clearing trend and decreasing winds as cold front continues to move southeast. Upper low centered over Saskatchewan/Manitoba on Wednesday fills and moves to the Hudson bay area by lateweek, while western CONUS ridge amplifies. Ridge axis extends across the Northern Plains by 00Z Mon.
The 500mb cut-off low continues to circulate over the Southern Plains at 08Z this morning per water vapor imagery. Stratus on the north side of the low will likely linger in eastern KS overnight. Have trended on the lower side of guidance for PoPs, but at least maintained slight chances mainly over eastern areas through the day. Chances of showers increase toward the evening and overnight hours when the CWA ends up in the deformation zone as the low moves northeast. Highs will reach the low to mid 70s with overnight lows falling back to the low 60s across the area.
VFR, mostly sunny and dry, conditions expected to prevail through the day today and into this evening as high pressure dominates South Texas. At the surface, high pressure across the Coastal Bend of Texas will drift eastward over the western Gulf by mid-morning, shifting winds back out of the southeast. With abundant sunshine and WAA, afternoon temperatures are expected to be about 10-15 degrees warmer today than yesterday afternoon -- low-mid 90s at most inland locations. This should keep temperatures on the warm side, with lows averaging in the low-mid 70s. The aforementioned mid-level low will finally lift northeastward late Thursday morning as strong ridging occurs over the Desert Southwest. Increased cloud cover should keep temperatures slightly cooler tomorrow compared to today, with high temperatures still reaching the low-mid 90s.
/issued 400 AM CDT Wed May 27 2020/ An upper level trough is over the southcentral part of the country. The upper trough will move over the Mississippi River Valley on Thursday with a cold front coming into West Texas and southeast New Mexico. Chances of showers and thunderstorms increase Thursday afternoon mainly across the higher terrain.