By: Stephen McCoy

Consistent late-spring conditions will be present for this weekend's race for the Kyalami 9 Hour. Low temperatures each day are expected in the upper teen's C, low 60's F, with afternoon high temperatures reaching the upper 20's C, low to mid 80's F. Pop up showers and thunderstorms are possible each day, especially in the afternoons, which may lead to cooler afternoon temperatures than predicted, depending on where the rain falls. Mostly clear to partly cloudy skies will be present during the mornings, but will give way to mostly cloudy conditions as storms begin firing off. Surface winds will stay mostly the same through the weekend, coming from the North during the mornings, then shifting to the Northwest during the afternoons.

By: Stephen McCoy

Much like was stated in the initial forecast, a trailing front from a surface low pressure system centered over Scandinavia will sit mostly stationary over the region on Thursday and into Friday. South to southwesterly winds along the frontal boundary will bring a likely chance for precipitation during the day, with some of the heaviest rainfall occurring in the later hours, near qualifying and/or the night practice session. Low level winds from the south to southwest will cause mostly cloudy to overcast conditions through much of the weekend.

A cold front extending from a low pressure system north of the British Isles is expected to move through the region on Friday, bringing another chance for showers ahead of it around mid-day. The front will weaken as it passes through, however low temperatures for Saturday morning are still expected to cool from Friday's, though not as severely as initially thought.

The weekend will round out with another cold front approaching the region from the west. Winds continuing from the south to southwest ahead of the front will bring slight chances for isolated showers on both Saturday and Sunday, though with lighter rainfall than seen earlier in the weekend. However, the front itself will bring heavier rainfall as it passes through Sunday, which could impact conditions in the final hours of the race, depending on the timing of the passage.

By: Stephen McCoy

It certainly won't be the conditions that the teams are typically used to for the 24 Hours of Spa. Temperatures for the weekend are looking to be in the upper 50's °F, or low teen's °C with chances for showers during the practice and qualifying days before somewhat clearer conditions move in for the race.

On Wednesday, a surface low pressure system is expected to move northeastward through mainland Europe, bringing warmer temperatures, strong winds and a likely chance for precipitation to the region. Entering Thursday, the system will be located over Scandinavia, with a front trailing behind to the southwest. The front is expected to sit mostly stationary over the region during the day, resulting in a chance for precipitation along the boundary. South to southwesterly winds will cause temperatures to be relatively consistent through the day, with a high only a few degrees warmer than the morning low. In addition, conditions will be mostly cloudy to overcast in the low levels through the day. The stationary front will move eastward out of the region overnight Friday, however a cold front from a low pressure system north of the British Isles will move into the region Friday afternoon, bringing a chance for scattered showers. South to southwesterly winds continuing overnight will keep temperatures relatively consistent with Thursday before the cold front passes and cools temperatures into Saturday.

After Friday's cold front passage, drier and slightly cooler conditions will move in for the 24 hour. Winds will shift towards the south to southeast for the race as another cold front begins a lengthy approach towards the region, passing through late Sunday or early Monday. Current model output is mixed on the passage time, though an earlier passage could mean heavier cloud cover for the race ahead of the front, with a later passage resulting in clearer conditions. An earlier frontal passage could also bring a slight chance for isolated showers, however for now there isn't enough to definitively say if rainfall will occur.

By: Stephen McCoy

Conditions were overall as expected for the Harvest GP, though with temperatures a bit warmer than anticipated. Now focus shifts to the Indianapolis 8 Hour where there is a large chance for precipitation, especially during the morning hours just before noon. The rain comes as the result of a cold front passing through the region on Sunday; winds ahead of the front will be from the southwest, causing steady temperatures through the overnight hours with a low expected around 50 °F. Mostly cloudy to overcast skies will be present for much of the morning and into the early-to-mid afternoon, though conditions are likely to clear into the late afternoon to evening as the front moves out of the region. The clearing skies will allow for temperatures to warm into the afternoon, though with north to northwesterly winds behind the front, high temperatures are expected in the mid to upper 50's °F.

By: Stephen McCoy

There have been a few changes to the temperatures for the weekend, but overall the forecast for Indianapolis Motor Speedway is still fairly consistent to the initial forecast from Monday. There is a slight chance for isolated showers on Friday, however rainfall rate for the day is expected in the hundredths of an inch, if any occurs.

The synoptic setup for the rest of the forecast period remains the same: a cold front passed through today, which will bring west to northwesterly winds to the region for tomorrow, resulting in cooler overall temperatures. A low pressure surface trough will approach central Indiana on Thursday from the north, bringing a chance for scattered showers in the afternoon. Rainfall totals are expected under a tenth of an inch, but still could disrupt some of the scheduled on track sessions. Behind the trough, high pressure will build in, causing surface winds largely from the north to northwest, continuing to cool temperatures with a morning low in the mid 40's °F and a high in the mid 50's °F.

The area of high pressure is anticipated to move over or close to the Indianapolis region, resulting in calm and variable winds during Saturday morning, with winds then shifting to the south to southwest in the afternoon as the system continues eastward. Saturday night, a warm front extending from a low pressure system to the west will pass through the area, causing Sunday's low temperatures to remain relatively unchanged from the previous day's high. Southwesterly winds behind the warm front and ahead of the pairing cold front will allow temperatures to warm a few degrees before cooling again as the cold front passes through. Both mentioned fronts could bring a chance for precipitation on Sunday, especially in the morning, however rainfall totals will be largely determined by the location of the surface low's center.

By: Stephen McCoy

Cool, early-fall conditions are expected for this weekend's races at Indianapolis Motor Speedway, with chances for precipitation present at the beginning and end of the forecast period.

On Wednesday, a surface low pressure system will pass north of the Great Lakes as it tracks eastward towards the Atlantic Ocean. A trailing cold front will move through Indiana during this time period, setting up cooler temperatures for the region in the following days. West to northwesterly winds overnight Wednesday and into Thursday will result in morning low temperatures in the upper 40's °F and a high in the low 60's °F as the winds continue through the day. Behind the front, there is the possibility of a surface trough extending westward through the Great Lakes region from the aforementioned surface low and moving southward into Indiana during the day. The movement of the trough could bring a chance for scattered showers to the Indianapolis region, especially during the afternoon and may impact the various on-track sessions during this time.

As the surface low continues towards the east coast, high pressure is expected to slowly build into the region over the first part of the weekend. With the center of the surface high to the west, winds on Friday will be largely from the north to northwest, accompanied by partly to mostly cloudy conditions in the low to mid levels for much of the day. The cooler temperatures will continue with a low similar to Thursday and a high in the mid 50's °F. The surface high is anticipated to move over the central Midwest Friday night into Saturday, resulting in calm and variable winds for most of the early part of the day before shifting to the south as the high moves eastward. The lack of wind movement will extend to the low levels of the atmosphere, causing mostly cloudy to overcast conditions; temperatures will be similar to Friday.

Leading up to Sunday, an upper level shortwave trough will allow a low pressure system to develop at the surface over the northern Plains late Friday evening. Due to the trough's orientation, the surface low is expected to track southeastward, centering itself over Illinois on Sunday. Current model output disputes the exact location of the low, but general consensus indicates the center of the system will be either to the west or southwest of Indiana. As a result, a warm front will likely extend from the low somewhere over central Indiana; model output shows a disparity in the low temperature for Sunday as a result of the front, with a range of 10 °F in the most recent runs. In any case, the system is expected to bring a chance for precipitation and overcast skies through much of the day.

By: Stephen McCoy

Conditions for the Bathurst 12 Hour remain mostly unchanged except for Sunday, which shows an increase in precipitation chances as the result of a cold front moving through the region. Much like in the initial forecast, a surface high pressure system is expected to sit stationary over the Pacific Ocean off the West coast of Australia. As it brings in warmer air from the North/Northwest, an upper level trough over the New South Wales territory will keep the heat trapped closer to the surface, resulting in temperatures well into the 30's C, 90's F on Friday and Saturday. Where this forecast update differs with the initial is that model guidance now suggests an upper level trough will move to the south of the continent, allowing a low pressure system to form at the surface, moving eastward Saturday into Sunday. A cold front will extend to the Northwest from the system, and is anticipated to move through the NSW region in the early to mid-afternoon on Sunday, bringing with it a chance for scattered showers with some thunderstorms possible. Maximum temperatures reflect the frontal passage, being a few degrees cooler than the rest of the weekend.

By: Stephen McCoy

A fairly straight-forward forecast for the Bathurst 12 Hours this weekend: lots of sun and hot temperatures each day. An upper-level ridge will sit over the NSW region with an accompanying surface high pressure system present just off the coast. North to northwesterly winds will bring warmer temperatures to the region, while the ridge will keep the heat trapped nearer to the surface. Northeasterly winds during the morning on Friday will bring in a slight amount of moisture off the Pacific Ocean and could result in some fog, but will any amount will disappear after sunrise. Slight amounts of smoke/haze are possible for the remainder of Friday from bushfires to the south, however the conditions are unlikely to continue for the rest of the weekend. Light cloud cover is expected for Saturday and Sunday as a result of mid level winds from the east, and will increase towards Sunday evening, but overall conditions will remain mostly sunny.