Aikyam-Lab/Synoptic-Bench huggingface dataset:
Thunderstorms are currently developing over eastern WY in response to the strong trough centered over the northern Rockies. This, coupled with additional cloud cover from redeveloping showers/storms, will keep Thursday's temperatures several degrees cooler than today. By late afternoon and evening, we should see thunderstorms redevelop just west of the forecast area, gradually translating eastward overnight as a 500mb vort max kicks out of the main upper low.
740 PM EDT Wed May 20 2020 High pressure will continue to bring very quiet weather with plenty of sunshine through Thursday.
The rex should keep the low locked over the lower Tennessee Valley for at least the next 24 hours. Carney By Thursday evening the low should start filling in and drifting north as the blocking high weakens and shifts eastward.
/issued 300 PM CDT Wed May 20 2020/ SHORT TERM (Now through Thursday Night): The fairly stationary deep mid level low currently over Tennessee will slowly lift northeastward through the short term, while the mid level low over the Northwest continues to elongate and become an open trough. As this trough progresses northeastward, it effectively weakens the ridge over the central U. Under the ridge this afternoon, temperatures are climbing into the mid to upper 90s across the region with high relative humidity values. As the ridge weakens, convection over the Sierra Madres will have the potential to drift across the Rio Grande into these western counties. Thursday will be hot and humid with similar heat indices, although slightly cooler than today under the weakening ridge, with no mentionable rain chances.
Drier air will move into western portions of the forecast area overnight as cold front slowly moves eastward. Deep western CONUS upper trough will slowly shift east and support increasing chances for TS in the western third through this evening.
Upper level analysis showed a cut-off low over Tennessee Valley with the moisture axis from the Carolinas to Florida Panhandle to the Louisiana Florida parishes to northeast Texas. Weak high pressure will remain over the northern Gulf and slowly migrate eastward through the end of the week. At the same time, the upper level low will slowly lift north to the Ohio Valley.
/issued 327 PM CDT Wed May 20 2020/ A pair of strong, closed lows continue to pinch off an upper- level ridge over the central CONUS today. This ridge is currently building over the top of the east TN upper low, forming a bit of a Rex Block across the region. This will keep this pesky trough in place through tomorrow, resulting in little change in the weather across the Mid-South.
743 PM EDT Wed May 20 2020 Large high pressure will settle across the area bringing not only fair and dry weather but a warming trend for the rest of this week.
951 PM EDT Wed May 20 2020 Upper low still sitting and spinning over the Tennessee Valley, but precip is only widely scattered at best and limited to eastern Kentucky at this time. With loss of heating Thursday evening, expect any ongoing scattered showers to wane, even as the slow-moving upper low makes its slow wobble northeast along the Ohio River.
Warmer temperatures can be expected on Thursday, with continued lighter winds.
Weak to moderate low-level southwest flow will reside across the region tomorrow as the 850mb ridge axis will be over South FL.
This front is attached to an area of low pressure that will be entering the Pacific Northwest near Seattle or Vancouver.
This is associated with an upper low centered over Idaho. The low pressure system has been generating gusty winds of 20-40 mph for many locations.
732 PM EDT Wed May 20 2020 VFR conditions will continue through tonight as dry easterly flow out of an area of high pressure keeps the skies mainly clear below 15kft with light easterly winds. The low pressure system to our south will begin drifting back north Thursday which will spread lower clouds around 5kft back into the region from south to north through the afternoon.
Here, IFR ceilings and visibilities will prevail before daybreak as the warm front drifts north.
SYNOPSIS: Widespread, deep low pressure, moist, warm air, and an unstable atmosphere will allow for strong to severe thunderstorms through tonight across all of NE Montana.
719 PM EDT Wed May 20 2020 Under persistent ridging, Upper Michigan has remained (mostly) cloud free and dry this afternoon. Going forecast was the 25th percentile, but under recent guidance this was cooler than the 10th percentile. Clear skies will last right into tomorrow under the ridge of high pressure.
302 AM CDT Thu May 21 2020 High pressure remains overhead today, but a quasi-stationary front will make a slow progression eastward over the next several days.
433 AM EDT Thu May 21 2020 Broad high pressure along the Mid-Atlantic coast will continue to maintain fair and dry weather today and tonight.
228 AM EDT Thu May 21 2020 Broad high pressure along the Mid-Atlantic coast will continue to maintain fair and dry weather today and tonight.
As an upper level trough approaches from the southwest later today both the RAP and NAM indicate that the early morning cloud cover southwest of a Dighton to Dodge City line will erode giving way to a sunny afternoon.
A low pressure system will slowly move east of the forecast area late tonight into Thursday morning. Brief high pressure Thursday will bring seasonable and dry conditions to most of the state.
219 AM CDT Thu May 21 2020 High pressure remains overhead today, but a quasi-stationary front will make a slow progression eastward over the next several days.
Not much change needed for the evening update as coverage of showers continues to slowly decrease in general, with any residual concentrated coverage focused on the eastern flank of the upper cyclone amidst deep sely flow across the Southern Appalachians.
249 AM CDT Thu May 21 2020 An upper level low pressure system drifting north into the Ohio Valley, will continue to bring cloudy and cool weather to central and southeast Illinois today.
325 AM CDT Thu May 21 2020 Water vapor imagery early this morning depicts a large-scale upper trough over the western CONUS, a pinched ridge of high pressure over the the Great Lakes Region, and a closed upper-low rotating over the Tennessee River Valley. The closed upper low has started to retrograde west and will eventually lift northward into the Ohio River Valley today, which has allowed southeast winds to pull low- level moisture/clouds back into the area.
1212 AM EDT Thu May 21 2020 VFR conditions will continue through the rest of the night as dry easterly flow out of an area of high pressure keeps the skies mainly clear below 15kft with light easterly winds. This is the northern extent of the low pressure system to our south will begin drifting back north Thursday.
442 AM EDT Thu May 21 2020 Broad high pressure along the Mid-Atlantic coast will continue to maintain fair and dry weather today and tonight.
Upper low still sitting and spinning over the Tennessee Valley, but precip is only widely scattered at best and limited to eastern Kentucky at this time. With loss of heating Thursday evening, expect any ongoing scattered showers to wane, even as the slow-moving upper low makes its slow wobble northeast along the Ohio River.
/issued 942 PM CDT Wed May 20 2020/ Upper low continues to spin over Middle TN this evening with bands of clouds rotating into the Mid-South. /issued 327 PM CDT Wed May 20 2020/ A pair of strong, closed lows continue to pinch off an upper- level ridge over the central CONUS today. This ridge is currently building over the top of the east TN upper low, forming a bit of a Rex Block across the region. This will keep this pesky trough in place through tomorrow, resulting in little change in the weather across the Mid-South.
There may be a lull in the chances late this evening before more scattered showers and thunderstorms develop overnight as a warm front lifts to near the Red River.
313 AM EDT Thu May 21 2020 High pressure will move offshore today as a low pressure system tracks up the east coast at the end of the week.
The rain will move out of the area overnight as the upper low shifts east. The next upper low located near the British Columbia coast will bring another round of showers by Thursday afternoon as it enters the Pacific Northwest. Temperatures will be around 10 degrees warmer on Thursday. Upper level low, with widespread MVFR rain and local IFR conditions over southwest Idaho this evening, moving slowly east out of area overnight, but leaving areas of IFR fog and low stratus, especially across the mountain valleys through morning.
235 AM CDT Thu May 21 2020 An upper level Rex blocking pattern continues east of the area which was keeping a closed low over the TN/OH valley region and most of our CWA within a cyclonic flow pattern northwest of the low. Some low cloud cover still affecting much of the eastern CWA because of the proximity of the low. Temperatures have also been held in check due to the low.
Temperatures will rise back into the 90s for many as we hang on to weak ridging and above normal 850mb temps.
146 AM EDT Thu May 21 2020 A wet pattern will continue into tonight as additional waves of showers and thunderstorms rotate through the region ahead of a strong low pressure system situated near the base of the southern Appalachians. Main upper level low will slowly begin lifting back to the north late tonight, but with plenty of moisture for much of the night, scattered showers should remain possible.
Our pesky cut-off low will slowly migrate northward into central Kentucky through the day. The highest POPs (30-50%) will be across western Kentucky, but have maintained at least a slight chance of showers across the entire forecast area. We'll ditch the cut off low tonight as weak ridging builds over the region.
Southeast winds will prevail around 5-7 knots, with low level moisture return beginning in earnest this afternoon and evening as a warm front to the south heads back to the north.
Another morning with low stratus and patchy drizzle is in place courtesy of the closed low over the Tennessee/Kentucky region. In western Nebraska, daytime convection just ahead of the trough in Idaho is dying out. This western trough is expected to continue its slow push eastward and will be the primary weather catalyst for the next several days.
The large upper level low centered over Tennessee will lift northward away from the area over the next 24 hours.
The front will gradually lift north out of the area through the day as the broad upper level low responsible for its infiltration begins to lift north across the Ohio valley. Weak ridging aloft will continue to build across the area in its wake which is expected to be enough to keep a lid on convection today.
310 AM CDT Thu May 21 2020 Water vapor imagery at 0730Z shows the upper ridge breaking down over the area as the trough over the western CONUS approaches the Plains. Temperatures will reach the low to perhaps mid 70s with cloudy skies persisting through the day.
Otherwise, VFR conditions will hold through at least early afternoon, when a few showers and storms are expected to develop with the highest rain chances over the interior and over southwest Florida.
This should all come to an end tomorrow but until then, the gusty winds continue as the low pressure to our northwest keeps that pressure gradient tight and a departing jet streak moves to the High Plains. Current radar imagery does show some convection firing over central Utah in response to a spoke of energy rotating around the low. Don't anticipate any precip hitting the ground as the lower levels remain very dry. Clear skies will allow some decent radiational cooling to kick in which will drop temperatures to freezing, if not a bit below. Mostly sunny skies expected as temperatures stay about 5 degrees cooler than normal. A few afternoon gusts remain possible but more on the order of 20 to 25 mph with a few higher gusts up north, closer to that low pressure.
319 AM CDT Thu May 21 2020 Satellite imagery this morning shows center of upper level low near Carthage and moving very slowly northwestward, while radar imagery shows a few showers over western and northeast Middle Tennessee.
143 AM EDT Thu May 21 2020 Under persistent ridging, Upper Michigan has remained (mostly) cloud free and dry this afternoon. Going forecast was the 25th percentile, but under recent guidance this was cooler than the 10th percentile. Clear skies will last right into tomorrow under the ridge of high pressure.
Expecting afternoon highs ranging from the low 70s in most of the north to low 80s in central GA.
451 AM EDT Thu May 21 2020 An upper low was near the Tennessee and Kentucky border early this morning.
1155 PM CDT Wed May 20 2020 We dealt with mostly cloudy skies along with some scattered showers and drizzle today, as an upper level low sat over Cookeville TN all morning. As we head into this evening and overnight, the low will eventually drift northward and become situated over central KY by tomorrow afternoon. However for tomorrow, with the upper low positioned just to our east, could not rule out some scattered rain shower activity once again, but mainly confined to parts of southwest IN and western KY. Meanwhile, a weak upper level ridge to our west will begin shifting eastward with time.
Warmer temperatures can be expected on Thursday, with light winds.
857 AM EDT Thu May 21 2020 Rain chances return today and Friday with crossing low pressure. At the surface and low- levels, high pressure is centered off the northeast coast. This has allowed for a rather persistent moisture stream in the residual warm conveyor belt of the meandering Ohio/Tennessee Valley low pressure. Precipitation spreading along a surface/mid-level trough and within this moisture stream will inch northeastward over the next several hours as the stacked low drifts northward. The low should continue its northward track tonight, before turning east across the Ohio Valley region Friday as it advances across the northwest periphery of the high. A few afternoon and evening thunderstorms are also possible Friday as minimal destabilization occurs, and the low crosses the region.
here we are, stuck in the middle with the ridge. The cut-off low still spinning over Kentucky and the Ohio River Valley will start to move northward today as the Omega blocking pattern finally begins to break down. The low will eventually get absorbed back into the westerly flow this weekend. The western low will still see some blocking today and as a result will continue to lift straight northward into western Canada. With the low falling apart to the east of us, we will gradually see a return to southerly flow which will continue to advect low-level moisture into the Plains. Storm chances increase this evening and overnight near the nose of the low-level jet.
Expect light shower activity today along trough axis as moisture continues to stream northward.
The expansive upper level low is still centered over Middle Tennessee, with associated heavy cloud cover over much of the region. This low is expected to retrograde westward back into our area this afternoon. This activity will come to an end this evening as the upper low finally lifts northeastward out of the area. Expect highs to climb into the mid to upper 80s each day, with heat indices approaching the low to mid 90s.
The synoptic set-up starts out with the area sandwiched between a mid-level low over northern Montana/southern Alberta and cut-off low pressure over the southeastern CONUS. Blocking high pressure over Great Lakes region to the northeast CONUS keeps things in place for most of the period.
Another morning with low stratus and patchy drizzle is in place courtesy of the closed low over the Tennessee/Kentucky region. In western Nebraska, daytime convection just ahead of the trough in Idaho is dying out. This western trough is expected to continue its slow push eastward and will be the primary weather catalyst for the next several days. This in combination of the advancing trough and increased moisture will result in showers across the area. The main focus for showers is expected in central Nebraska on Thursday, but the trough's slow eastward progression will shift the main focus for precipitation to eastern Nebraska and western Iowa for Friday.
A ridge of high pressure will build over the area this weekend.
Otherwise, an upper low is forecast to move across OR/WA during the next 48 hours, with associated precipitation development currently expected to remain north of the EKA CWA.
642 AM CDT Thu May 21 2020 An upper level low pressure system drifting north into the Ohio Valley, will continue to bring cloudy and cool weather to central and southeast Illinois today.
A closed upper level low is expected to produce three weak fronts through friday morning as it tracks through Washington and Oregon. Elsewhere in southwest Oregon and Northern California impacts include, cooler temperatures, increased low and mid level cloud cover, and breezy to windy west to northwest winds.
730 AM EDT Thu May 21 2020 Outer reaches of midlevel moisture from Southeast US upper low will brush southern Lower Michigan from east to west. The upper level low will begin to move northward later today bringing with it an increase in high cloud. Blocked flow keeps the broad upper low that was associated with the heavy rain earlier this week over the Ohio and Tennessee Valleys today into early Friday. Ridging aloft otherwise dominates the story for the late week for eastern North America with the jet stream over Hudson Bay. Highs today /mid 60s to lower 70s/ will be a slight improvement from yesterday as the airmass continues to slowly warm in the late May sun, though another day of east to southeast flow keeps the immediate lakeshore cooler.
A western Atlantic ridge axis extending across South Florida, and extending well into the Gulf of Mexico will lift northward into Central Florida on Friday, before settling near the Gulf coast region early this weekend.
At the surface, the subtropical ridge axis over southern Florida will gradually lift north to a position across central Florida by Friday.
957 AM CDT Thu May 21 2020 The cut-off upper low continues to meander around the OH Valley this morning, providing northwest flow aloft across the Mid- South. The expansive upper level low is still centered over Middle Tennessee, with associated heavy cloud cover over much of the region. This low is expected to retrograde westward back into our area this afternoon. This activity will come to an end this evening as the upper low finally lifts northeastward out of the area. Expect highs to climb into the mid to upper 80s each day, with heat indices approaching the low to mid 90s.
648 AM EDT Thu May 21 2020 An upper low was near the Tennessee and Kentucky border early this morning.
536 AM EDT Thu May 21 2020 Rain chances return today and Friday with crossing low pressure. A closed low over the Tennessee Valley should begin to drift north today around an upper high as it builds off the Eastern CONUS. The low should continue its northward track tonight, before turning east across the Ohio Valley region Friday as it advances across the northwest periphery of the high. A few afternoon and evening thunderstorms are also possible Friday as minimal destabilization occurs, and the low crosses the region.
Today Through Friday Night Early this morning, a stalled/quasi-stationary front was located from north texas into the western Gulf Coast region, with a cold front coming off of the Rockies. In the upper levels, a trough was over the Panhandles Region of Texas and Oklahoma down into Northern Mexico/South Texas. Additional development of showers/storms is likely tonight and early Friday, as the warm front stalls over Arkansas, and another series of upper waves move through and interact with it.
309 AM MDT Thu May 21 2020 The upper low over Montana will move off to the north today. At the surface, a N-S oriented trough/front will be located over the eastern part of the forecast area. Deep moisture and instability to the east of the trough will create a chance of showers and thunderstorms over parts of south central South Dakota. Dry weather is expected over the rest of the forecast area due to southwesterly surface winds and lower relative humidity to the west of the trough.
530 AM CDT Thu May 21 2020 Water vapor imagery early this morning depicts a large-scale upper trough over the western CONUS, a pinched ridge of high pressure over the the Great Lakes Region, and a closed upper-low rotating over the Tennessee River Valley. The closed upper low has started to retrograde west and will eventually lift northward into the Ohio River Valley today, which has allowed southeast winds to pull low- level moisture/clouds back into the area.
Later today, as the upper low over the OH Valley wobbles back northward, expect a more widespread MVFR deck to spread in and linger through at least Friday morning. The upper low that's sitting over the KY/TN border will drift northward to southern Ohio through Friday. I kept temperatures on the conservative side for Friday due to anticipated cloudiness, but there is a chance that more of southern WI could be in the lower 70s rather than upper 60s.
As an upper level trough approaches from the southwest later today both the RAP and NAM indicate that the early morning cloud cover southwest of a Dighton to Dodge City line will erode giving way to a sunny afternoon. The line of thunderstorms that will develop early Thursday evening will move across southwest and south central Kansas Thursday night as the upper level trough crosses southwest Kansas. Highs today under the low clouds will range from 70 to near 75. Further southwest where afternoon sunshine is expected the highs will range from the upper 70s to near 85. As the upper level trough crosses southwest Kansas late tonight/early Friday morning the thunderstorms will taper off from northwest to southeast.
423 AM CDT Thu May 21 2020 A slow moving, cut-off upper level low over north central TN will move north-northwestward into southern IN this evening, then northeastward through southern OH on Friday as a negatively tilted upper level trough moves into eastern Nebraska and western IA. There will be patchy drizzle this morning with isolated light showers this afternoon into the evening, mainly across southeast MO and southwest IL, west of the upper low.
753 AM EDT Thu May 21 2020 Broad high pressure along the Mid-Atlantic coast will continue to maintain fair and dry weather today and tonight. High pressure then exits out to sea, which will allow low pressure to our south to introduce a few showers to our region on Friday and Friday night. Broad high pressure along the Mid-Atlantic will promote another sun filled day across the region. Tonight, low pressure to our south will begin to lift towards the Ohio Valley and our region.
The front will gradually lift north out of the area through the day as the broad upper level low responsible for its infiltration begins to lift north across the Ohio valley. Weak ridging aloft will continue to build across the area in its wake which is expected to be enough to keep a lid on convection today. This ridge is progged to slide east of the area by Friday allowing for isolated to scattered diurnally driven afternoon convection each afternoon Friday through the weekend.
Water vapor imagery at 0730Z shows the upper ridge breaking down over the area as the trough over the western CONUS approaches the Plains. Temperatures will reach the low to perhaps mid 70s with cloudy skies persisting through the day. Southwesterly flow will keep temperatures from cooling down too much, with lows in the low 60s.