Aikyam-Lab/Synoptic-Bench huggingface dataset:
The lower levels of the atmosphere where it is raining are rain cooled and likely to be more stable this afternoon which decreases the chance for thunderstorms in these areas. the low will move north- northwest today allowing the southern portion of the forecast area to see more sunshine and the atmosphere to become unstable for another round of scattered thunderstorms with about a 30 percent chance of any one location being impacted by a thunderstorm late this afternoon and evening.
The upper level ridge will continue to dominate our weather into the weekend, with very hot temperatures persisting. Saturday will see the beginning of even hotter temperatures as the upper ridge intensifies a bit and H85 temps warm a degree or two.
158 PM MDT Fri Aug 4 2023 High temperatures will trend cooler today as high pressure slides south from Canada, with below to well below normal temperatures expected this weekend. As we head into the day tomorrow, the monsoonal moisture and clouds will continue to linger across the area, and northerly surface winds will help bring some cooler air into the area. Even with this cooler air, we may still wind up with some instability that will fuel some afternoon showers and thunderstorms across the area, especially over the terrain of Central Montana.
Thinking that a Theta-e ridge over Garfield county will bring convection to the western edge of the stratiform area and Garfield County this afternoon.
At the surface, a low pressure system will remain over the western and central part of the state tonight, keeping that region as the main focus area for showers and thunderstorms. Low temperatures tonight will be in the lower to mid 60s. When the period opens Saturday night, rain chances are ongoing across the CWA as an occluded low pressure system should be spinning eastward over the region.
Upper- level ridging remains in place overhead which will keep subsidence in place. With increasing thicknesses temperatures should be a degree or two warmer across the region with high temperatures ranging from the century mark to near 108 degrees under mostly sunny skies.
1234 PM MDT Fri Aug 4 2023 Minor convective development at this time, mostly over the higher mountains. The high resolution models are not very excited concerning convection this afternoon and evening, with the highest coverage over the northern border of the CWA.
A front will move through the region early next bringing slightly cooler temperatures and not as humid conditions.
232 PM CDT Fri Aug 4 2023 An anomalously strong low pressure system will drift onto the Plains tonight and bring a chance for showers and thunderstorms. The main question with severe appears to be in the evening as the main vort lobe swings into the area and could in a very localized manner enhance the shear just ahead of the incoming cold front.
245 PM EDT Fri Aug 4 2023 A cold front will push south of Pennsylvania tonight, followed by high pressure building in from the Great Lakes over the weekend.
This heating, along with mid level troughing is producing another round of convection northwest of Valdosta, GA.
259 PM MDT Fri Aug 4 2023 Satellite imagery shows split low pressure areas. Precip in our east will taper off Saturday afternoon and evening as the low continues to move east and is replaced by anticyclonic flow aloft, while a weak trof remains stagnant over the PacNW. Tomorrow night should be a mostly dry and seasonably cooler night with potentially some fog.
A well advertised wave will drop out of the High Plains and take shape as it sharpens a negatively tilted trof into across the MO/MS valleys.
1048 AM MDT Fri Aug 4 2023 High temperatures will trend cooler today as high pressure slides south from Canada, with below to well below normal temperatures expected this weekend. High temperatures across the plains of North Central and Central Montana today with this shift to northerly surface winds will trend 5-8 degrees cooler than yesterday, with the valleys of Central and Southwest Montana trending and additional 2-4 degrees cooler on average.
Fine details are near impossible to discuss until there is confidence in the exact location of the low pressure.
(Tonight through Saturday night) Upper ridging continues to influence South-Central Texas today, tomorrow, and for the foreseeable future.
Discussion: Upper level northwesterly flow will continue with a ridge centered near Texas. With mostly sunny skies tomorrow, temps will be warmer with highs near 90 for most of the Valley.
Looking into tomorrow we may have some lower clouds over much of the area like today which will limit the morning temps before clearinmg out and warming up, but overall temps are expected to be marginally "cooler".
Current observations show an upper low spinning over the NE/WY/SD border with storms beginning to form along the southeastern leading edge. For tomorrow, the upper level trough and a cold front begin to move south towards the area. The cold front and colder air aren't likely to move through the area until late in the day with pressure differences responsible for the winds from the north. The further north the low develops/moves, the higher the chance of a surface convergence zone developing over the area that can serve as a focus for storm development during the afternoon hours. Otherwise, storm development may be more limited to over the higher terrain in Eastern Colorado. This will keep the area from heating up like the past month as the upper ridge will stay more suppressed.
- Severe weather is possible ahead of a cold front on Saturday evening. Light southerly flow will turn to the northwest and become breezy overnight behind a cold front. Upper low near the Black Hills now will sweep southeast on Saturday and open as it approaches Iowa. Still on track to see convection developing as the cold front pushes through the area on Saturday afternoon and evening. Breezy winds behind the front will gust up to 40mph, pulling in drier and cooler air.
142 PM EDT Fri Aug 4 2023 A weak cold front will sag south into central Ohio before washing out. Otherwise, high pressure will prevail through Saturday.
Upper low currently out in southeastern MT will wobble eastward tonight into the Dakotas. With easterly winds at the low levels, smoke from Canadian wildfires that was over west central MN this morning will be pushed further west and should start to dissipate under the low. Rain will begin to move into southeastern ND from the west overnight, and should wrap us as a deformation band as the low deepens to our south. There is still some variation in the ensemble members on how the upper low is handled, with most of the members showing the southern solution described above.
A slight chance of rain for WI counties bordering IL has recently been added to the forecast in response to model guidance hinting the potential for an early surge of moisture and rainfall far ahead of the low.
- A few severe storms still possible, mainly Saturday night as a stronger cold front moves through. Overnight, surface ridging behind the MCV may keep things drier compared to the last several nights. Could also see some patchy fog if skies stay mostly clear, given the high humidity and light winds.
/Tonight through Friday/ Key Messages: - Unsettled & turning cooler with two primary rounds of showers/storms.
1215 PM EDT Fri Aug 4 2023 A cold front will push south across Pennsylvania late today, then high pressure will build in from the Great Lakes over the weekend.
245 PM EDT Fri Aug 4 2023 Isolated to scattered showers and storms are possible this afternoon and evening along a weak cold front.
1150 AM MDT Fri Aug 4 2023 High temperatures will trend cooler today as high pressure slides south from Canada, with below to well below normal temperatures expected this weekend. High temperatures across the plains of North Central and Central Montana today with this shift to northerly surface winds will trend 5-8 degrees cooler than yesterday, with the valleys of Central and Southwest Montana trending and additional 2-4 degrees cooler on average.
351 PM EDT Fri Aug 4 2023 Tranquil weather will continue tonight into Saturday morning under weak high pressure.
An elongated area of high pressure in the upper atmosphere stretched AZ to the Gulf of Mexico with a stronger center from SE AZ to SW NM. Subsidence under the high has dried out the atmosphere well below normal levels for early August.
Upper circulation redevelops over the PacNW with band of precipitation extending along warm frontal structure across panhandle into Montana north of the Divide.
1253 PM CDT Fri Aug 4 2023 (Today through Saturday) Mid-level ridging over Texas will continue to be the driving force for the weather through the period. The low temperatures for tonight are expected to be in the upper 70s to low 80s.
Despite this reprieve from the heat, both Key West and Marathon Airports still managed to reach the lower 90s.
Nearly stacked low pressure will move into South Dakota tonight taking much of the steady rainfall in that direction.
(Tonight through Saturday night) Key Message: - Dangerous heat and elevated fire weather conditions Saturday Although the center of the ridge will shift towards extreme West Texas through the weekend, the eastern periphery will remain stretched over South Texas, preventing the trough originating from the Midwest to extend southward Saturday into Saturday night.
(This afternoon through Saturday night) Upper ridge with 594 high remains over AZ, NM, TX, and LA today. This ridge will expand westward Saturday into Srn CA with a 597 high developing over NM.
/22/ For the rest of the weekend, a high pressure system located over the desert Southwest will continue to bring hazardous heat to the region.
The marine layer is expected to get shallower and more confined to coastal areas through the weekend as a ridge of high pressure settles over Southern California and the desert Southwest.
456 PM PDT Fri Aug 4 2023 Warming trend through the weekend as an upper level ridge migrates over the area. The difference? Much warmer temperatures (5 to 10 degs warm), especially away from any marine influence. However, inland coverage of clouds will be less as a marine compressed marine layer develops due to building high pressure. Speaking of high pressure, upper level high pressure over the Desert SW will continue its westward march.
This is based on observed high temperatures today, and the forecast for temperatures at or slightly warmer in some spots on Saturday compared to today. (Tonight through Saturday night) Upper ridging continues to influence South-Central Texas today, tomorrow, and for the foreseeable future.
1022 PM EDT Fri Aug 4 2023 Showers and storms have developed today with a cold front shifting west to southeast this afternoon; some severe storms and isolated flash flooding has occurred with potential for more through this evening.
Will still go ahead with a Heat Advisory for those locations, given the multi day heat wave, even though temps could be slightly cooler tomorrow that what has been seen due to clouds. The upper ridge is expected to continue to break down and shift westward over the next couple of days.
However, as the clouds cleared in the afternoon and the sun evaporated the wet rain, it resulted in the development of muggy conditions and temperatures in the lower 90s. A weak high pressure stretching from the central Atlantic westward across the Bahamas will promote light mainly southeast breezes, becoming variable at times in the afternoon and evening hours, across the Florida Keys coastal waters through Saturday night.
1023 PM EDT Fri Aug 4 2023 Showers and storms have developed today with a cold front shifting west to southeast this afternoon; some severe storms and isolated flash flooding has occurred with potential for more through this evening.
543 PM CDT Fri Aug 4 2023 (This afternoon through Saturday night) Upper ridge with 594 high remains over AZ, NM, TX, and LA today. This ridge will expand westward Saturday into Srn CA with a 597 high developing over NM.
Otherwise, high pressure will begin to build across the area with dry pleasant summertime weather for most of the weekend.
628 PM CDT Fri Aug 4 2023 An upper low continues to slowly spin over northwestern South Dakota, feeding moisture up into southwest and south central North Dakota.
With the dominant midlevel ridge continuing to reside over much of the Southern CONUS while light to moderate onshore winds prevail at the surface, heat and humidity remain the main concern heading into tomorrow. Our main concern in the short term period is of course the potential for excessive heat tomorrow with the prevailing ridge remaining largely the same in terms of both position and magnitude.
Looking into tomorrow we may have some lower clouds over much of the area like today which will limit the morning temps before clearing out and warming up, but overall temps are expected to be marginally "cooler".
An upper low continues to slowly spin over northwestern South Dakota, feeding moisture up into southwest and south central North Dakota.
650 PM CDT Fri Aug 4 2023 (Tonight through Saturday night) Upper ridging continues to influence South-Central Texas today, tomorrow, and for the foreseeable future.
1042 PM EDT Fri Aug 4 2023 High pressure will begin to build across the area with dry pleasant summertime weather for most of the weekend.
625 PM CDT Fri Aug 4 2023 An anomalously strong low pressure system will drift onto the Plains tonight and bring a chance for showers and thunderstorms. The main question with severe appears to be in the evening as the main vort lobe swings into the area and could in a very localized manner enhance the shear just ahead of the incoming cold front.
803 PM EDT Fri Aug 4 2023 Aviation Today is unfolding as expected, with north winds and beautiful weather as a very weak cold front has passed through the area. Otherwise, the main impact will be thicker midlevel clouds spreading across our southern zones and keeper temperatures a bit cooler during the day.
724 PM EDT Fri Aug 4 2023 Tranquil weather will continue tonight into Saturday morning under weak high pressure.
There is a bit over the high mountains of Larimer and Boulder Counties and some over southern Elbert County. Models have flat upper ridging for the CWA overnight with pretty weak flow aloft. The thickness fields show a cold front moving into the CWA late Saturday afternoon. 5 over the higher foothills to 1. The highest CAPE values are over the eastern border area early this evening, with the highest values on Saturday afternoon to be over the foothills and immediate plains. Pops should be a bit higher on Saturday afternoon with 20-40%s for the foothills and western half of the plains, including the Palmer Ridge.
926 PM EDT Fri Aug 4 2023 A cold front will wash out while pushing south of Pennsylvania tonight. High pressure will build in from the Great Lakes over the weekend.
941 PM EDT Fri Aug 4 2023 Tranquil weather will continue tonight into Saturday morning under weak high pressure.
609 PM CDT Fri Aug 4 2023 (Tonight through Saturday night) Key Message: - Dangerous heat and elevated fire weather conditions Saturday Although the center of the ridge will shift towards extreme West Texas through the weekend, the eastern periphery will remain stretched over South Texas, preventing the trough originating from the Midwest to extend southward Saturday into Saturday night.
Overnight low temperatures tonight are forecast to range from the upper 70s across much of the region to the low to mid 80s across the Metroplex. Dangerously hot early August temperatures will persist through the remainder of the weekend as a subtropical ridge, though eroding and retreating to the southwest, will remain dominant over the Southern Plains.
900 PM CDT Fri Aug 4 2023 Looking at the latest upper air analysis from 05/00z, the strong upper level ridge is right on top of the forecast area.
A cooler Canadian airmass will also keep temperatures around 5 degrees below normal. As we head into the day tomorrow, the monsoonal moisture and clouds will continue to linger across the area, and northerly surface winds will help bring some cooler air into the area. Even with this cooler air, we may still wind up with some instability that will fuel some afternoon showers and thunderstorms across the area, especially over the terrain of Central Montana.
Weak high pressure will build in for the weekend. As the weak low pressure over eastern NC shifts east through the night, there should continue to be a slow eastward push of drier air aloft from the northwest. Despite being behind the front, temps will actually be a bit warmer than today, thanks primarily to far less cloud cover. Highs in the mid/upper 80s, with lows in the lower 70s.
Inland temperatures has been running 5 to 10 degrees warmer compared to yesterday's reading, especially for Mendocino and Lake counties. Models are in general agreement on heights building on Saturday with 850 mb warming as the offshore trough lifts out and weakens.
The severe weather threat has shifted south as much if not all of the forecast area remains north of the surface warm front and in more stable easterly flow through Sunday afternoon, with the bulk of the rain holding off until Sunday night.
A well advertised wave will drop out of the High Plains and take shape as it sharpens a negatively tilted trof into across the MO/MS valleys. The very warm/soupy/charged airmass in place here will be encountered by the cold front it drives into/across the FA late Sunday into Sunday night. All modes severe are possible with particular emphasis on hail/wind along and ahead of the linear/frontal portion of the system encountered here, better helicity being nearer the track of the surface cyclone to the north. Highs dropping into the lower half of the 80s will feel even better with dew points falling back into the 60s. Warmer temps, higher humidity, and pops, transition back into the forecast for the latter half of the week.
Weak high pressure will follow and extend across the middle Atlantic through Sunday. As the weak low pressure over eastern NC shifts east through the night, there should continue to be a slow eastward push of drier air aloft from the northwest. Despite being behind the front, temps will actually be a bit warmer than today, thanks primarily to far less cloud cover. Highs in the mid/upper 80s, with lows in the lower 70s.
1253 AM CDT Sat Aug 5 2023 (Tonight through Saturday night) Key Message: - Dangerous heat and elevated fire weather conditions Saturday Although the center of the ridge will shift towards extreme West Texas through the weekend, the eastern periphery will remain stretched over South Texas, preventing the trough originating from the Midwest to extend southward Saturday into Saturday night.
1058 PM PDT Fri Aug 4 2023 The weekend will be cloudy and cooler with increasing chances for showers and thunderstorms.
The convective mode this evening, as is often the case in the warm season, will depend on how far south the low level baroclinic zone gets shunted due to overnight thunderstorm outflow. The southern and southwestern counties could be cooler in the upper 80s to near 90 given the overnight cooling rains and boundary to the south.
1045 PM CDT Fri Aug 4 2023 An anomalously strong low pressure system will drift onto the Plains tonight and bring a chance for showers and thunderstorms. The main question with severe appears to be in the evening as the main vort lobe swings into the area and could in a very localized manner enhance the shear just ahead of the incoming cold front. Sunday will see low pressure shift east with a fairly tight surface pressure gradient filling in behind.
252 AM EDT Sat Aug 5 2023 High pressure will bring dry and seasonable weather for today and Sunday.
234 AM MDT Sat Aug 5 2023 Stacked surface and upper low is located over western South Dakota this morning. The low will move east today and most of the rain from this system will stay south and east of the forecast area.
A cold front will settle into the forecast area early this afternoon bringing another chance for showers and storms. Expect convection to develop over northeast Nebraska around 4 PM and continue to bubble up along the cold front, before exiting the CWA around 10 PM tonight. The low pressure system associated with the passing cold front will drift from northeast Nebraska into Iowa, wrapping additional precipitation into the forecast area through the remainder of the weekend. Temperatures will be significantly cooler on Sunday, with highs only reaching the mid 70s at most locations.
1104 PM EDT Fri Aug 4 2023 High pressure will build in from the Great Lakes tonight and Saturday. A warm front will bring some showers in from the west later Sunday.
1114 PM EDT Fri Aug 4 2023 High pressure will build in from the Great Lakes tonight and Saturday. A warm front will bring some showers in from the west later Sunday.
1136 PM CDT Fri Aug 4 2023 Looking at the latest upper air analysis from 05/00z, the strong upper level ridge is right on top of the forecast area. Rua (Tonight through Sunday night) Water vapor shows our resident mid/upper-level ridge still extending from the Desert SW across TX to the wrn Gulf. Meanwhile, sfc analyses show high pressure centered over the cntl Gulf maintaining a swrly/sometimes wrly low-level flow. The ridging aloft is progged to maintain its hold on our area weather through the weekend, which should keep convection at bay, at least through Saturday.
High pressure is firmly entrenched in the Great Lakes region this evening and that will remain the case through the night. Today is unfolding as expected, with north winds and beautiful weather as a very weak cold front has passed through the area. Otherwise, the main impact will be thicker midlevel clouds spreading across our southern zones and keeper temperatures a bit cooler during the day.
249 AM EDT Sat Aug 5 2023 High pressure will build in from the Great Lakes tonight and Saturday. A warm front will bring some showers in from the west later Sunday.
200 AM CDT Sat Aug 5 2023 Very slow moving upper trof/low over the Dakotas this morning, will continue to move/dig slowly to the southeast over the next couple of days, providing for fairly widespread rains to the region through tonight. There is a bit of a lull in the activity currently, but with daytime heating and another wave rounding the trof, expect an expansion of convection again this afternoon over the northeast part of SD.
Forecast soundings have show a long, skinny CAPE profile, along with the high PWAT values. The timing for this system is dependent on the timing of the MCV tonight into tomorrow, how long it takes to move out of the region, and on when the cold front is set to move through.
The 500 mb ridge remains over the forecast area and vicinity, which is steering any precipitation or cooling pattern away from South Texas.
148 AM EDT Sat Aug 5 2023 Following the passage of a cold front, high pressure will bring dry and seasonable weather for today and Sunday.
Temperatures were generally in the low 80s with dewpoints running in the upper 70s. Summertime high pressure was centered over Texas, forcing a very dry mid level airmass over the forecast area.
As an upper low pulls into eastern Washington and Oregon, this will spread weak vorticity advection into western zones overnight, which will keep the chance of showers going through the night. The western upper low fills and slides across Idaho and into northwest Wyoming Sunday, for more ascent for showers and thunderstorms.
- Severe weather is possible ahead of a cold front on Saturday evening.
- A few severe storms still possible, mainly Saturday night as a stronger cold front moves through. Overnight, surface ridging behind the MCV may keep things drier compared to the last several nights. Could also see some patchy fog if skies stay mostly clear, given the high humidity and light winds. The cold front will push through the area by Sunday morning, bringing in cooler and much drier air in its wake.