Aikyam-Lab/Synoptic-Bench huggingface dataset:
354 PM CDT Sun Aug 25 2019 With the sea breeze sticking closer to the Coastal Bend this afternoon and a trough axis lingering aloft, multiple showers and storms have dropped some beneficial rain with nearly 2. Meanwhile, the broad upper trough axis will continue departing northeast of the region overnight ahead of rising heights and increasingly anticyclonic flow aloft. Deterministic and ensemble output suggest that an upper approximately E-W upper ridge will influence mainly the south- central and SWRN CONUS early in the period, while an upper disturbance/trough affects the CNTRL/NRN Plains.
A cold front is moving across western Montana this afternoon. The other weather impact is increasing gusty westerly winds across the region coinciding with a cold front passing through.
248 PM CDT Sun Aug 25 2019 18Z surface data has high pressure from New England back into the eastern Great Lakes. Monday afternoon the next cold front will move into the area during peak heating.
For this forecast package, we opted to continue with the Excessive Heat Watch and expand it to include most of the lower elevations of West Texas and southeast New Mexico.
Upper trof to our west will approach tonight, increasing forcing across the area, while a low trop boundary responds by moving north, allowing for increasing moist and warm advection over the area. Should be a lull in convective activity late Monday afternoon and evening, in the wake of the initial H5 trof axis.
Rain chances return Monday night with an approaching cold front. In the middle of the morning, diurnal cumulus started pouring over the eastern ridges with easterly surface winds, something models are struggling to handle. Upper ridging over the region will maintain dry and quiet conditions today and tonight. Winds will slowly veer on Monday as ridging continues to transition east.
As trough passes through the area tonight, guidance is depicting another round of showers and thunderstorms to develop along the coast into lower portions of Acadiana. This activity is expected to diminish gradually through the day tomorrow as the trough pushes east of the region.
145 PM EDT Sun Aug 25 2019 A large area of high pressure will continue to extend down the eastern seaboard into our region into Monday.
749 PM CDT Sun Aug 25 2019 Will allow a tier or two of the western counties within the watch to expire with this update as the sfc cold front continues to push east this evening. However, storms have struggled to sustain themselves in this low shear environment. A cold front, currently stretched across central North Dakota, will continue to move east and be the focus for thunderstorm initiation across central North Dakota late this afternoon.
1030 PM EDT Sun Aug 25 2019 Low pressure well offshore is producing N/NE wind flow across the area, with breezy conditions along the Volusia coast this evening.
Thunderstorms should develop along an approachin cold front and possible impact KBVO before 00Z. With temperatures warming into the low to mid 90s across much of the area, the result will be afternoon heat index values ranging from 105 to 113, except a bit lower in far northwest Arkansas. As a cold front enters the area late Minday afternoon or early evening, strong to severe thunderstorms are expected to develop near the front given very strong instability, with large hail and damaging winds being the main severe weather hazards.
/Issued 354 PM CDT Sun Aug 25 2019/ With the sea breeze sticking closer to the Coastal Bend this afternoon and a trough axis lingering aloft, multiple showers and storms have dropped some beneficial rain with nearly 2. Meanwhile, the broad upper trough axis will continue departing northeast of the region overnight ahead of rising heights and increasingly anticyclonic flow aloft. Deterministic and ensemble output suggest that an upper approximately E-W upper ridge will influence mainly the south- central and SWRN CONUS early in the period, while an upper disturbance/trough affects the CNTRL/NRN Plains.
Other than the winds, Monday will be quiet and cooler as high pressure builds in behind the front. Low temperatures will be cooler than they have been for awhile, and trended towards cooler guidance of lower to middle 50s.
Thunderstorms should develop along an approaching cold front and possible impact KBVO before 00Z. With temperatures warming into the low to mid 90s across much of the area, the result will be afternoon heat index values ranging from 105 to 113, except a bit lower in far northwest Arkansas. As a cold front enters the area late Monday afternoon or early evening, strong to severe thunderstorms are expected to develop near the front given very strong instability, with large hail and damaging winds being the main severe weather hazards.
18Z surface data has high pressure from New England back into the eastern Great Lakes. Monday afternoon the next cold front will move into the area during peak heating.
Several arching bands of showers and storms are developing in a region of large scale ascent/DPVA ahead of the short wave trof now located near the MO/KS border. This activity should continue to grow and spread eastward across the CWA tonight in association with the migration of the short wave trof. All indications are the axis of the short wave trof and ascent should be east of the CWA by 12z Monday. The air mass across the region is expected to become quite unstable as temperatures warm into the lower-mid 80s. A broken line of thunderstorms is expected to develop during the afternoon along/ahead of the advancing cold front across northwest MO with the line moving into northeast and central MO during the early evening and then southeastward across the remainder of the area from late evening through the overnight hours.
A northern stream upper trof now approaching the Mississippi valley will continue an eastward advance. As trough passes through the area tonight, guidance is depicting another round of showers and thunderstorms to develop along the coast into lower portions of Acadiana. This activity is expected to diminish gradually through the day tomorrow as the trough pushes east of the region.
With temperatures warming into the low to mid 90s across much of the area, the result will be afternoon heat index values ranging from 105 to 113, except a bit lower in far northwest Arkansas. As a cold front enters the area late Minday afternoon or early evening, strong to severe thunderstorms are expected to develop near the front given very strong instability, with large hail and damaging winds being the main severe weather hazards.
Current surface analysis shows low pressure over western ND, with cold front extending south into northwest SD and the Black Hills area. Much cooler and brisk conditions can be expected for the first half of the week as strong northwest flow aloft develops behind strengthening system to the northeast of the region.
GAH AFTERNOON DISCUSSION: An upper trough is moving east across the area with a disturbance now over north-central Montana.
Low clouds and areas of fog may once again be an issue overnight across western Kansas given the upslope flow and moisture profiles from the BUFR soundings in the lowest 500 to 2000 ft AGL. The potential exists that lows in the 50s will be possible outside the area of fog and stratus while under the returning cloud cover tonight the lows are expected to be mainly in the 60s. Models today remain fairly consistent with yesterday's model run in moving a cold front into southwest Kansas late Monday as an upper level trough, embedded in a northwesterly flow, crosses the Northern Plains.
Numerous waves of rain and thunderstorms continue to overspread the western 2/3 of the forecast area this evening in response to broad ascent ahead of an upper level trough over the Mississippi Valley and a very moist airmass in place. 2 inches of precipitable water along with a freezing level above 14 kft which have supported very high rainfall rates as high as 4 inches per hour in places. Off- and-on rain will continue across much of the area throughout the night as the main upper trough makes only slight eastward progress through tomorrow morning.
Chattanooga Airport, TN 68 76 70 85 / 50 60 70 50 Knoxville McGhee Tyson Airport, TN 68 78 67 84 / 30 40 60 60 Oak Ridge, TN 68 77 67 84 / 40 60 60 50 Tri Cities Airport, TN 61 78 64 82 / 10 20 50 60.
UPDATE Will allow a tier or two of the western counties within the watch to expire with this update as the sfc cold front continues to push east this evening. However, storms have struggled to sustain themselves in this low shear environment. A cold front, currently stretched across central North Dakota, will continue to move east and be the focus for thunderstorm initiation across central North Dakota late this afternoon.
305 PM MDT Sun Aug 25 2019 An upper trough is moving east across the area with a disturbance now over north-central Montana.
Ridge of high pressure remains over Central California today, meaning another day of above normal heat.
An upper level ridge of high pressure will remain over the area through the forecast period. For this forecast package, we opted to continue with the Excessive Heat Watch and expand it to include most of the lower elevations of West Texas and southeast New Mexico.
With the trough sitting off the eastern seaboard, the Bermuda high remains disrupted and shunted to the south. The ridge axis remains to our south over Cuba, which leaves the CWA in southwesterly flow through 700mb, with light winds above in the mid troposphere. Isolated showers and thunderstorms are possible, particularly in the early morning hours near sunrise in the nearshore waters of the lower and middle Keys.
Extreme heat is likely through at least midweek under a strong ridge of high pressure.
520 PM MDT Sun Aug 25 2019 Current surface analysis shows low pressure over western ND, with cold front extending south into northwest SD and the Black Hills area. Much cooler and brisk conditions can be expected for the first half of the week as strong northwest flow aloft develops behind strengthening system to the northeast of the region.
619 PM CDT Sun Aug 25 2019 Weak upper-level ridge of high pressure to build across the region overnight into Monday allowing for mainly dry conditions areawide. /Tonight through Monday Night/ The upper level trough will continue to eject out of the Four State Region this evening and will take the ongoing convective activity with it. By tomorrow, the upper level ridge will push back into the area from west, and along with it, drier air aloft.
Hot, humid conditions will lead to substantial instability (ML CAPE of 2,000-4,000 J/kg) prior to the arrival of a strong cold front from the NW late this afternoon. A return to cooler than normal and drier conditions is expected mid-week. During the overnight hours, warmer and more moist air will be transported back into southwest Missouri ahead of an approaching cold front. The other concern will be for scattered thunderstorms moving into southwest Missouri Monday evening along the cold front, primarily near or just after the end of this TAF period, especially for JLN. Surface winds will generally be from the southeast at 5-10 knots through 15Z, before increasing to 10-15 knots during the afternoon and veering to the northwest as the cold front pushes through tomorrow evening.
A cold front will enter northeast Oklahoma by 00Z, with thunderstorms impacting most of the TAF sites through 06Z. Thunderstorms should develop along an approaching cold front and possible impact KBVO before 00Z. With temperatures warming into the low to mid 90s across much of the area, the result will be afternoon heat index values ranging from 105 to 113, except a bit lower in far northwest Arkansas. As a cold front enters the area late Monday afternoon or early evening, strong to severe thunderstorms are expected to develop near the front given very strong instability, with large hail and damaging winds being the main severe weather hazards.
The presence of the vorticity lobe, the exit region of an upper-level jet streak nosing through SD and NE, and an advancing cold front are all mechanisms which should sustain a subset of the ongoing storms through our area this morning into afternoon. However, the influence of residual surface ridging from the Great Lakes into mid MO Valley has displaced the axis of highest boundary-layer moisture to our south and west with a progressively more stable environment with eastward extent. Showers could linger across portions of northeast NE into west- central IA into mid afternoon with some potential for storm intensification near the KS and MO borders as the cold front encounters an increasingly unstable air mass.
340 AM CDT Mon Aug 26 2019 (Today and Tonight) An upper level high pressure ridge will remain across the Southern Plains today.
310 AM CDT Mon Aug 26 2019 Scattered showers and thunderstorms will continue today and tonight as a cold front approaches the area. followed by cooler and drier weather for the remainder of the week. Low temperatures will range from the lower 60s northwest of the Illinois River. to the lower 70s along/southeast of I-70. The cold front will quickly push into Indiana by Tuesday morning, with any lingering precip coming to an end by early afternoon.
The winds will be more of a concern Tuesday, with the ridge strengthening to our west and low deepening to near 993mb across Ontario.
Current surface analysis shows low pressure over western ND, with cold front extending south into northwest SD and the Black Hills area. Much cooler and brisk conditions can be expected for the first half of the week as strong northwest flow aloft develops behind strengthening system to the northeast of the region. Nighttime lows will drop into the mid 40s to mid 50s, with some 30s likely over the higher Black Hills Monday night and Tuesday night. Weak disturbances and another cold front toward the end of the week could bring a few showers and storms, but most areas will likely stay dry.
Temperatures should be a bit cooler today, but will quickly rebound starting tomorrow.
A cold front could be faintly seen on both water vapor imagery and the Air Mass RGB Composite of GOES-16. Conditions greatly improve tomorrow thanks to the cold front, with highs for much of the forecast area being 20-30 degrees colder.
Tuesday, a cold front is expected to approach from the North.
425 AM EDT Mon Aug 26 2019 High pressure remains centered over the Northeast U. An approaching cold front will spread showers in from the west starting Tuesday night.
By later this afternoon and especially this evening, advancing cold front will encounter a very unstable airmass over northeast OK.
216 AM EDT Mon Aug 26 2019 A large area of high pressure centered across southern Quebec will maintain mostly clear and tranquil weather conditions across the North Country through Tuesday.
A cold front will then move through the terminals this evening, complete with breezy northeasterly winds. A cold front moving south out of the Texas Panhandle Monday evening will push through the South Plains and Rolling Plains by early Tuesday morning and linger between our southern zones and the I20 corridor into midweek.
Cloudy skies and showers will continue through Tuesday, with drier and cooler conditions expected through the remainder of the week. Can't rule out an isolated rumble of thunder as the upper trof axis lifts across the region, but feel there is just a slight chance. High temperatures will be held down into the lower 70s with the pcpn and clouds. As the trof axis lifts off to the north Monday night, pcpn chances will gradually taper off. A cold front will be moving through the region Tuesday into Tuesday night.
Cloudy skies and showers will continue through Tuesday, with drier and cooler conditions expected through the remainder of the week. With the saturated column, expect thick cloud cover and below normal temperatures today with highs only in the lower 70s. As this upper trough lifts ENE across the region through early evening, expect the more widespread showers to also lift east, bringing a short-lived lull in precipitation after about 00-03z. Don't have enough confidence to go completely dry for tonight with the area caught between the upper trough and approaching cold front. Temperatures slightly warmer in the upper 70s to lower 80s. Showers and a few thunderstorms should be ongoing across the area Tuesday evening in association with a cold front pushing east through the upper Ohio Valley.
High-res guidance has been doing a good job of capturing the lower ceilings.
It will be a cooler night with lows in the 50s. Tuesday will feel like a much cooler day with dew points dropping into the upper 40s/lower 50s and high temperatures in the lower 70s. Enhancing the cooler feel will be breezy northwesterly winds in the afternoon, gusting around 30 to 35 mph at times. A secondary cold front will drop across the area in the afternoon/evening as a couple of upper level impulses round the upper level trough situated over the Upper Mississippi Valley, and some models are suggesting the possibility of a few showers over southwestern MN, though left it mainly dry for now.
As the trough moves east today, a drier, more subsident air mass will settle over the Mid-South. This complex of storms is progged to dissipate later this morning but another round of storms will develop along the attendant cold front this afternoon, moving across the Ozarks during the evening hours.
334 AM EDT Mon Aug 26 2019 High pressure remains centered over the Northeast U. An approaching cold front will spread showers in from the west starting Tuesday night.
Warmer than average conditions are expected to persist into the Labor Day Weekend.
Upper trof to our west will approach tonight, increasing forcing across the area, while a low trop boundary responds by moving north, allowing for increasing moist and warm advection over the area. Should be a lull in convective activity late Monday afternoon and evening, in the wake of the initial H5 trof axis. Then later Monday night into Tuesday morning, surface cold front will move into and then across the area, offering another chance of showers and storms. Highs will continue to be below seasonable averages, in the lower half of the 80s.
1220 AM CDT Mon Aug 26 2019 The focus in the short term is overnight passing of a cold front and potential for thunderstorms. Late tonight, a cold front will approach from the northwest. Though its a cold front, temperatures for many areas will be warmer than today simply because we will have some well-deserved sunshine in the afternoon. Monday night will bring cooler temperatures with lows in the 50s and Northwest winds dropping off as high pressure moves toward the forecast area. Pretty dry in the low levels (thank goodness) so little more than a trace would fall, and mostly just across parts of south central Nebraska.
319 AM CDT Mon Aug 26 2019 Upper level trof continues to slowly track to the east across forecast area as of 08z Monday. Warm front associated with system will lift north of forecast area by midday today with showers and storms exiting.
High pressure surface and aloft will hold over the region through Tuesday with weak onshore boundary layer flow.
Meanwhile a ridge of high pressure was building into the area and the dry conditions can be expected into tomorrow. Currently a large upper ridge is centered well offshore with our area under the eastern side with a dry northwest flow over the area. The ridge will gradually move to the coast over the next couple of days with the ridge axis moving overhead by Tuesday afternoon. This will also give us a warming trend with tomorrow a couple of degrees warmer than today.
414 AM EDT Mon Aug 26 2019 High pressure will extend down across the eastern seaboard into central North Carolina through Tuesday morning.
Other than the winds, Monday will be quiet and cooler as high pressure builds in behind the front. Low temperatures will be cooler than they have been for awhile, and trended towards cooler guidance of lower to middle 50s. A trough sits over the northern Plains and Midwest Tuesday with a ridge moving over the west coast.
The temperature forecast uses the guidance blend which keeps temperatures very cool Tuesday; highs in the lower 70s. We also get a second reinforcing cold front sending h700mb temperatures into the low single digits Celsius.
Another cold front will move out of Canada tonight and bring clouds and showers for Tue.
The cumulus cloud cover that was scattered across the High Country earlier today has since dissipated. Look for this high- based cloud cover to slowly move northeastward into the early overnight period.
A convectively enhanced vorticity maximum just nnw of Saint Louis MO will continue to migrate slowly east-northeast into northern IL today, while at the surface a warm front approaches from the Ohio Valley. Ramping low level southerly flow downstream of the upper wave, and over this warm front, will transfer a wall of deep moisture northward into the local area later this morning into this afternoon. Leftover mid level wave and an associated pre-frontal trough/warm front will keep chances for rain showers in the forecast into tonight.
Thunderstorm coverage and intensity will be limited by marginal instability but heavy rain potential exists overnight with p-wats around 2 inches as the cold frontal rain bands move through, MBE vectors look less conducive for flooding than 24 hours ago as storm motions should remain greater than 10 knots during this event but some minor flooding will be possible if any training develops.
143 AM EDT Mon Aug 26 2019 Dry conditions and seasonable temperatures can be expected through Tuesday with high pressure remaining in control. A cold front approaching from the west will bring the chance for showers Tuesday night.
446 AM EDT Mon Aug 26 2019 High pressure will gradually loosen its grip on the region as a weakening front approaches from the west.
333 AM EDT Mon Aug 26 2019 Multiple swirls are located within an elongated trough that stretches across most of the Mississippi River Valley. On Tuesday, upper flow revolves around a large low pressure system slowly moving east through southern Canada. Impacting southern Indiana and central Kentucky will be a cold front stemming from the larger low pressure system.
UPDATE Will allow a tier or two of the western counties within the watch to expire with this update as the sfc cold front continues to push east this evening. However, storms have struggled to sustain themselves in this low shear environment. A cold front, currently stretched across central North Dakota, will continue to move east and be the focus for thunderstorm initiation across central North Dakota late this afternoon. The cold front will usher in gusty winds and cooler air for Monday and Tuesday, with Tuesday the windier day.
Will keep onset of likely PoPs from southwest to northeast across the area in the 12Z-16Z timeframe as better low level moisture convergence becomes established with a more defined warm frontal feature lifting northward. Perhaps some very weak elevated instability develops after 12Z with this warm frontal feature, but will continue to omit thunder mention at this time due to the forecasted weak nature of the instability. Newd pivot of lead convectively augmented sw disturbance over ern KS this aftn will allow warm frontal zone and attendant deep moisture surge to overspread the region on Monday. Otherwise showers likely Monday with lead sw trough/warm front lifting through. Slightly faster consensus solution wrt to ewd cold frontal progression Monday night/early Tuesday warrants further pop reductions Tuesday aftn.
For the Austin area airports, the MVFR signal is not that clear at this time and going with SCT015 to show the low level clouds trend without changing category.
312 AM EDT Mon Aug 26 2019 A large area of high pressure centered across southern Quebec will maintain mostly clear and tranquil weather conditions across the North Country through Tuesday.