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This weather satellite photo of Earth taken Thursday, a day before the spring equinox, shows how sunlight will shine at a 90-degree angle to the equator on the day of the equinox.<\/p>\n
Geostationary Operational Environmental Satellites\/CIRA and NOAA<\/p>\n
On Friday we mark the spring equinox, traditionally known as the first day of spring<\/a>. However, the start of spring in Austin<\/a> will feel more like the start of summer, as we kick off a string of days featuring 90-degree weather in Austin that could match or break daily heat records, some dating back more than 50 years, according to the National Weather Service<\/a>.<\/p>\n Rain continues to be elusive<\/a> in the daily forecast and, with low humidity levels this week<\/a>, we\u2019ll have an elevated threat of fast-spreading wildfires this weekend.<\/p>\n Article continues below this ad<\/p>\n Expect another sunny day in\u00a0Austin on Friday, with balmy south-southwest winds of 5 to 10 mph helping push afternoon temperatures into the lower 90s. If the forecast high of 91 holds up, that would be about 15 degrees\u00a0warmer than normal and would match the daily record for March 20 set exactly 50 years ago in 1976.<\/p>\n Austin temperatures could reach 90 degrees by 4 p.m. Friday, according to the National Blend of Models, a composite weather forecast model.<\/p>\n National Blend of Models\/Pivotal Weather<\/p>\n Although we\u2019ll have\u00a0clear skies Friday night, the persistent southerly winds will help keep overnight temperatures above 60 degrees before dawn Saturday.\u00a0<\/p>\n Heat dome and high fire threat<\/p>\n Heralding the start of an especially warm spring season in Austin is the arrival of a system of high atmospheric pressure that will produce a heat dome<\/a> over Texas. The high pressure causes air to sink toward the ground, where the compression of air causes temperatures to increase. A resulting \u201cdome\u201d of heat and pressure ends up trapping the water vapor-laden warm air like a pot lid, and denying any chances for rain clouds to form in the upper atmosphere.<\/p>\n Article continues below this ad<\/p>\n \u201cSubsidence underneath the ridge (of high pressure) and below-seasonal average moisture levels keep rain out of the forecast,\u201d the weather service said in a forecast discussion<\/a> posted online Thursday.<\/p>\n<\/p>\n
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