Tropical Cyclone Heidi is expected to cross the Pilbara coastline early tomorrow morning and as the system approaches, rainfall figures are mounting. Heidi is moving south towards the WA coast at approximately 15 km/h as a Category 1 tropical cyclone. The system is expected to cross the coast near Port Hedland early on Thursday morning and could reach Category 2 strength before making landfall. Moisture wrapping around the system has been producing heavy rain in WA for days, with Newman in the southern Pilbara recording 52mm on Monday and 65mm on Tuesday, making it their heaviest 2 day total in 10 years. Bidyadanga received 50mm to 9am this morning, the heaviest rain since January last year. As Heidi drew nearer and cloud blanketed the Pilbara this morning, Curtin was drenched by 18mm of rain in the hour to 9am, including 8mm in just 10 minutes. Tropical Cyclone Heidi will cause rain and wind to intensify as it approaches the coast tonight, with the most severe conditions expected to the east and south of the cyclone's center. The latest official warning indicates that rainfall totals could reach 100-250mm through the central and eastern Pilbara over the next 24 hours, although heavier falls are possible. Tides are also expected to push above their usual height between Wallal and Whim Creek. After crossing the coast, Tropical Cyclone Heidi is expected to move in a southwesterly direction, weakening below tropical cyclone strength on Thursday. Computer models indicate that the low will move into southwestern WA later in the week, which may have an effect on this weekend's cricket.