Aikyam-Lab/Synoptic-Bench huggingface dataset:
/Issued 317 PM EDT Wed May 26 2021/ The upper level ridging shifts east.
Latest water vapor satellite loop shows a mid level trough over western Montana and western Wyoming at 1945Z. Profilers show some perturbations emanating from the Rockies out into the high plains. Surface analysis had a dryline in eastern Colorado along or just east of the front range with a warm front extending from southeast Wyoming through northwest Kansas and into central Kansas at 18Z. CAMS have had a difficult time resolving the convection today as they have not done well with the development in central Kansas along the warm front. Outflow from earlier convection helped to increase convergence along the warm front for additional storm development. Another round of severe convection is expected across northeast and east central Kansas with the higher probability near and south of the boundary in the afternoon.
At the surface, deep high pressure over central Canada was encompassing the north Plains/upper Midwest. A warm front attendant to an area of low pressure over southeast extended southward into central KS with a thermal boundary continuing across MO to the southern Great Lakes.
Upper level analysis has a trof extending down the Rockies and a ridge over the High Plains, resulting in southwest flow across the forecast area. At the surface, an area of low pressure is located over southeastern Wyoming with a warm front extending across the Nebraska/Kansas line. Sunny and warmer conditions are mainly south of I-90. The warm front will continue to push northward as MLCAPE values continue to increase this afternoon. The northern extent of severe storms will be limited, with the warm front expected to extend across nebraska. The upper low will track slowly eastward along the ND/SD border on Thursday.
Latest thinking is that moist upslope low level flow will generate storms this afternoon across the high plains region of western Nebraska which will then travel east/southeast tonight along that mid-level frontal boundary.
As we go through the remainder of the night, look for this high thin cirrus to continue moving into our region from the west.
On Thursday, an upper level trough begins digging southward through the central Plains, which will provide upper level support for storms later in the day. Overcast skies will return through most of the day on Thursday, as a surface cold front begins to move southeast through Kansas and arrive in far northwestern Oklahoma in the late afternoon.
Several pockets of organized storms continue eastward having originated across the High Plains.
744 PM EDT Wed May 26 2021 Scattered showers and storms will gradually diminish as the evening progresses, and a cold front will cross the remainder of the commonwealth overnight.
627 PM CDT Wed May 26 2021 A cool day across the area with northerly flow keeping low level dew points pretty low, mostly in the lower to mid 40s. On Thursday the upper level low collapses south and should keep a chance for showers and isolated thunderstorms throughout the day. Day time temperatures will be much cooler than we have felt lately, running about 15 to 20 degrees below normal. This low pressure slowly shifts southeast on Thursday night and should take the precipitation chances with it.
For that reason, have decided to nudge high temperatures along this swath down a few degrees and lean towards the cooler side of guidance this afternoon. A weak cold front is still on track to slide across the northwest portion of the CWA this afternoon and evening, becoming a focal point for storm initiation after 21Z. The low to our north drifts east of the Divide overnight and the area falls under split flow aloft, with a weak transitory ridge to the north and shallow trough south of the Four Corners.
722 PM EDT Wed May 26 2021 Showers will gradually diminish with passage of a cold front this evening. Building high pressure should return dry weather and seasonable temperatures to the region through Thursday as it tracks across the Great Lakes region.
651 PM CDT Wed May 26 2021 Summary: Much cooler temperatures are on tap for the next several days with the possibility of frost. A secondary cold front pushed through this morning allowing for cooler temperatures to move into the region with highs in the mid 50s over the Arrowhead to the lower 60s further south and into northwest Wisconsin. Behind the cold front is cooler air that will stick around through much of the week. Overnight lows for Thursday look to be in the low 30s which has lead to a Frost Advisory over our far northern counties tonight, and potentially over a large area Thursday night with Freeze Warnings possible. With the cooler air in place some models are hinting at snow for our far southern zones by Thursday afternoon as low pressure propagates to the south of the Northland.
Most of this activity will diminish in areal coverage and intensity through the rest of the day, as it runs into drier air in the low levels. Thicker cloud cover and shower activity looks to move in just a bit slower this afternoon from the west, as a dampening short wave trough moves east of the Mississippi Valley today.
643 PM EDT Wed May 26 2021 Showers will gradually diminish with passage of a cold front this evening. Building high pressure should return dry weather and seasonable temperatures to the region through Thursday as it tracks across the Great Lakes region.
It has all but lost all of the upper level support it once had as the upper level ridge is pushing east and away from the eastern U. Pushing it east is an upper level trough that extends from the north central Gulf into the eastern Great Lakes region. This upper level trough can be clearly seen on water vapor imagery as it moves southeast in our general direction. This is thanks to the subtropical jet riding along the base of the aforementioned upper level trough. moves out into the Atlantic with the ridge axis shifting southwards into Florida through the remainder of the week.
Atmosphere remains dry with high pressure over the area although there are signs of decreasing subsidence aloft and gradually increasing moisture in the form a few showers that developed over parts of Charlotte and Lee counties this evening.
936 PM EDT Wed May 26 2021 Scattered showers and storms will push east of the commonwealth overnight, as a cold front will crosses the region.
306 PM MDT Wed May 26 2021 Organized low pressure system spinning across Montana is spreading multiple areas of rain showers across most of northeast Montana this afternoon.
The WRF-NAM (which one out yesterday) is further to the west with the dryline and further north with a cold front (the latter boundary was pushing southward through northeastern Colorado and southwestern Nebraska at 2 AM) than the hi- res models which favor a further southward progression of the cold front and a robust push eastward to the dryline which would squeeze the severe risk further east, almost confined to the Rolling Plains. Furthermore, the final position of these two boundaries will have a fairly large effect on afternoon high temperatures with the hi-res models showing potential for mid-90s temperatures west of the bulging dryline but cooler than the blend north of the front.
-Much cooler conditions are expected to develop tonight and continue into the holiday weekend. Forecast area will be located in warm sector ahead of a cold front sweeping southeast through the afternoon hours. Have generally broadbrushed pops throughout the day, but tried to focus greatest pops immediately ahead and along the cold front moving through the area. With the cloud debris through the day, have sided with slightly cooler guidance values to the north, with warmer conditions bottled up to the south. Much cooler conditions expected behind the cold front, and with strong cold air advection, have winds gusting tonight into Friday.
1105 PM EDT Wed May 26 2021 Scattered showers and storms will push east of the commonwealth overnight, as a cold front will crosses the region.
The area is situated under a weak pressure pattern, sandwiched between high pressure to our east over the Atlantic waters, another ridge to our west over the northeastern Gulf waters, with a positively tilted upper level trough axis laid out over the Florida Peninsula. With mainly high pressure dominating the local weather pattern, the heat will continue, but moisture has already begun to return to the region.
07Z surface obs show a relatively moist airmass still over east central KS while the latest 850MB profiler data shows the low level jet beginning to veer more to the south-southwest with decent speed convergence into east central KS. The main uncertainty in the short term forecast is whether storms continue through the morning pushing an outflow through much of the CWA or is there a break in precip allowing the airmass to recover as a more synoptic cold front pushes through this afternoon. Have continued with highs in the lower 80s across east central KS as southerly winds continue to advect warmer air into the area.
SHORT TERM (Now through Friday): A 500 mb ridge will continue to build over Deep South Texas through the short term.
344 AM CDT Thu May 27 2021 Summary: A large system brushes the southern portion of the forecast area today followed by widespread freezing conditions tonight. With such a cold day in store, it won't take much for temperatures to drop below freezing tonight as high pressure builds. There is some chance that a few lingering clouds will be around, but overall feel quite confident that the area will see widespread freezing temperatures. There will be a sharp cutoff with the precipitation gradient on the northern edge of the low pressure that passes today with only a sliver of QPF ending up in our forecast area.
A cold front will push through late tonight into Friday allowing for severe storms to develop.
After a warm, somewhat muggy day with highs in the low to mid 80s, lows will drop into the lower 60s to around 70 tonight, with lower humidity levels.
(Today and tonight) The trend over the last day or so is for the air mass center over southern Manitoba this morning to build south more quickly behind a cold front and be centered over the central plains by Friday morning with around a 1025mb MSLP. Additionally, the upper low over southeastern MT this morning is expected to move into the upper Mississippi Valley by late tonight.
Activity should exit the western Nebraska panhandle between 6 to 8 pm this evening (00z to 02z) with cooler temperatures expected overnight. A much drier airmass will be over the area on Thursday with a small chance of a few brief showers or thunder showers, mainly near the ridges and mountains across the area. A cold front moves through the CWA from the north Friday and stalls across our western zones through the weekend.
Isolated showers continue to develop along a low level trof axis located across west Alabama. Satellite imagery shows the upper trof axis has shifted into east Alabama with significant mid level drying across west Alabama. Kept pops on the low side with highest values along and east of the I-20/59 corridor. A late season cold front will approach northwest Alabama Friday afternoon.
Tranquil conditions will continue until Thursday afternoon, when isolated to scattered thunderstorms will begin developing across Northeast Arkansas and the Missouri Bootheel ahead of an approaching cold front. High pressure will then begin to build into the area Friday Night into the weekend. Have trended cooler with temperatures based on latest guidance. Dry conditions will continue into Memorial Day with highs expected to climb into the upper 70s to mid 80s as upper ridging begins to occur over the area.
Although the ridging aloft will be increasing slightly from the west, the sufficient moisture along with convergence along a seabreeze boundaries and diurnal heating may allow at least for the development of isolated showers and thunderstorms over portions of the region Thursday afternoon and will keep POPs around 20% for much of the area. Still hot on Thursday with highs ranging from the lower 90s over much of the interior to the mid and upper 80s along the coast. Thursday night the slight ridging aloft and surface ridging poking in from the east will maintain a dry forecast with partly cloudy skies.
Additional rain is possible Friday along with much cooler temperatures. In addition, 00/06Z HRRR indicate that the outflow boundary will surge well to our south and greatly hamper mid/late afternoon destabilization as new storms form in response to low pressure moving across the state. Should a picture paint out similar to the NAM solution, then all severe hazards would be in play later this afternoon, including a tornado threat depending on the eventual placement of warm frontal boundary progged to be draped across Illinois. This should lead to some lighter rain Friday with the highest PoPs focused north of I-72. Breezy northeast winds will contribute to much cooler conditions across central Illinois.
Deep layered ridging of late will weaken and shift east through Friday as a short wave trough moving across the southeastern states impinges upon it. On Friday a continued slow increase in moisture combined with less suppression from the aforementioned ridge may lead to some much needed isolated showers or storms (Pops 20 percent) developing along the inland moving sea breeze boundaries over inland locations during the afternoon, otherwise dry and hot conditions will continue elsewhere with light winds again becoming onshore along the coast with the sea breeze during the afternoon.
For Thursday into Thursday night, models show a low pressure system moving from Iowa into central Illinois. This will slowly drag a cold front toward the middle Mississippi and lower Ohio valleys. The cold front will move across the PAH forecast area late Thursday night into Friday morning. High pressure will build over the eastern U.
325 AM EDT Thu May 27 2021 Dry weather is expected today under building high pressure. Rain returns Friday and Friday night with crossing low pressure. Building high pressure across the Upper Ohio Valley and Great Lakes region should result in dry weather today. The high should maintain dry weather through this evening as it moves east. The low is expected to pull a warm front N across OH into Wrn PA Friday.
1029 PM MDT Wed May 26 2021 Organized low pressure system spinning across Montana is spreading multiple areas of rain showers across most of northeast Montana this afternoon. Friday, especially during the afternoon and evening, another large and strong trough of low pressure approaches from the west.
A mid-level trough across the TN Valley will continue to shift very slowly southeastward overnight, along the northeastern rim of a subtropical ridge centered along the Pacific Coast of Mexico. Thursday we will be under weak ridging with ample moisture and a very unstable environment by the afternoon. With convective temperatures in the low-to-mid 80s, and forecast high temperatures in the mid-to- upper 80s, it's fair to say we will probably reach it by early to mid-afternoon for isolated to scattered air mass thunderstorms.
Current sfc analysis shows the area continuing under the influence of high pressure centered over the nern Gulf which was maintaining a light onshore low-level flow across the region. Combo of the weak ridging aloft and slightly lower moisture profiles should allow for a dry day across the forecast area today. Some of the high res guidance is showing a stray shower or two, mainly during max heating, but at this time coverage looks slim enough to leave any significant POPs out of the grids/zones. Meanwhile the next disturbance aloft will help push a weak sfc trof/frontal boundary into the forecast area by Friday night.
Summary: Much cooler temperatures are on tap for the next several days with the possibility of frost. A secondary cold front pushed through this morning allowing for cooler temperatures to move into the region with highs in the mid 50s over the Arrowhead to the lower 60s further south and into northwest Wisconsin. Behind the cold front is cooler air that will stick around through much of the week. Overnight lows for Thursday look to be in the low 30s which has led to a Frost Advisory over our far northern counties tonight, and potentially over a large area Thursday night with Freeze Warnings possible. With the cooler air in place some models are hinting at snow for our far southern zones by Thursday afternoon as low pressure propagates to the south of the Northland.
The 850 mb thermal ridge will continue to strengthen to between 20- 23 deg C across the area with surface temperatures following suit and rising just a bit higher than today into the upper 80s and low 90s. Our western counties and the Big Country will have the highest probability of seeing strong to severe storms.
310 AM EDT Thu May 27 2021 Drier and cooler air behind a cold front will filter in overnight into Thursday. Much cooler temperatures for Friday with highs only into the 50s and lower 60s. Expect mostly clear skies and notably cooler temperatures with at least partial boundary layer decoupling. Showers likely and colder Friday as upper level low deepens across southern portion of Upper Great Lakes.
1046 PM CDT Wed May 26 2021 A cool day across the area with northerly flow keeping low level dew points pretty low, mostly in the lower to mid 40s. On Thursday the upper level low collapses south and should keep a chance for showers and isolated thunderstorms throughout the day. Day time temperatures will be much cooler than we have felt lately, running about 15 to 20 degrees below normal. This low pressure slowly shifts southeast on Thursday night and should take the precipitation chances with it. That will feel pretty chilly after the warmer weather that we have had. Friday and Friday night look pretty quiet and cool as high pressure aloft moves through.
Friday will be a little warmer, then cooler for the weekend with coastal low clouds spreading farther into the valleys as the marine layer again deepens.
High temperatures are expected to be in the low to mid 70s. Low temperatures are expected to be in the low to mid 40s. 850mb temperatures warm a few degrees across the western CWA where some short wave ridging moves in ahead of a larger upper level low centered north of Montana. High temperatures are expected to be in the low to upper 70s.
The big action for this period will occur from after sunset Thursday evening through the first half of Friday as a strong cold front drops into Arkansas from the northwest, pushes southeastward, then exits the state to the south. High temperatures Friday afternoon will be somewhat cooler overall from highs reached Thursday and will generally range from the lower 70s over the northern higher terrain to the mid 80s over the far south.
Some of the high-resolution model guidance is very fast with this complex and suggests impacts may be ongoing before the end of this TAF cycle at KTXK, KGGG, KTYR, and KSHV. As we go through the remainder of the night, look for this high thin cirrus to continue moving into our region from the west.
1111 PM EDT Wed May 26 2021 Showers will gradually diminish with passage of a cold front this evening. One more band of showers should cross the region tonight along/ahead of a crossing cold front. Building high pressure should return dry weather and seasonable temperatures to the region through Thursday as it tracks across the Great Lakes region. The rain should continue through part of Friday night as the low tracks east, though rain will remain possible as the lingering upper trough approaches.
236 AM MDT Thu May 27 2021 As an upper-level ridge builds into the region. This ridge will also keep dry and tranquil weather around through the day tomorrow before the ridge begins to break down early Friday morning. A digging trough will dive into the region bringing a cold front with it.
1239 AM EDT Thu May 27 2021 Showers will gradually diminish with passage of a cold front this evening. One more band of showers should cross the region tonight along/ahead of a crossing cold front. Building high pressure should return dry weather and seasonable temperatures to the region through Thursday as it tracks across the Great Lakes region. The rain should continue through part of Friday night as the low tracks east, though rain will remain possible as the lingering upper trough approaches.
Showers and thunderstorms are expected to develop along a cold front moving southward thru OK and into n TX tonight.
Upper trof entering SD will advect across the state today. In any event it's likely some areas will drop to near or even below freezing overnight, provided we lose the sky cover. S/W ridging behind departing system will allow for more sun and moderating temperatures on Friday, but temperatures will still be below average.
451 AM EDT Thu May 27 2021 Cooler and drier conditions expected Thursday following the passing of a front. Widespread rain and much colder for Friday as a low pressure system passes to the south. Cooler air begins to fill in this morning behind the passing of a cold front. Drier conditons and mostly to partly sunny skies are also expected today with the presence of high pressure. A low pressure system over the Ohio River Valley begins to make its way east brining increasing cloud cover tonight. During the early Friday morning hours, a chance of showers is introduced for western parts of the Southern Tier and Finger Lakes regions as an area of widespread rain associated with the low pressure system begins to enter the region.
Upper level analysis has a trof extending down the Rockies and a ridge over the High Plains, resulting in southwest flow across the forecast area. At the surface, an area of low pressure is located over southeastern Wyoming with a warm front extending across the Nebraska/Kansas line. Sunny and warmer conditions are mainly south of I-90. The warm front will continue to push northward as MLCAPE values continue to increase this afternoon. The northern extent of severe storms will be limited, with the warm front expected to extend across nebraska. The upper low will track slowly eastward along the ND/SD border on Thursday. Warmer and drier on Friday with short wave ridging.
With ongoing clouds across much of the area outside of the NW MN, where temps have fallen below freezing at a few locations, these clouds will limit daytime temps as the weak short wave slides across the area today. As the system pulls away and skies clear from north to south this evening dry airmass in place along with light winds with high pressure axis sliding across the area will allow raditonal cooling to be efficient with temps falling at least into the low 30s for most areas. Current thinking is that a Fargo to Fergus Falls to Alexandria line may not fall quite into freeze range with lingering clouds and any areas that see rainfall today trending a bit warmer than the 32 degree criteria.
/Issued 317 PM EDT Wed May 26 2021/ The upper level ridging shifts east. An elongated cold front associated with this disturbance will bring increasing chances for showers and thunderstorms to north Georgia on Friday as it approaches the forecast area. With a moist and destabilizing boundary layer co-located with some enhanced deep- layer shear ahead of the cold front, there is a possibility that isolated storms in north Georgia could become strong to severe Friday afternoon and evening.
1205 AM EDT Thu May 27 2021 High pressure will remain over the area through Friday.
However, the primary cold front will be moving through during the morning hours so may continue to have some remnant showers with it. Friday is a transition day, with a breezy northwest wind ushering in the cooler, drier airmass.
LW Chattanooga Airport, TN 87 68 88 60 77 / 20 20 80 60 20 Knoxville McGhee Tyson Airport, TN 86 67 86 60 72 / 10 20 80 70 20 Oak Ridge, TN 85 66 86 58 72 / 10 20 90 70 20 Tri Cities Airport, TN 84 63 84 59 70 / 10 10 80 80 40.