Wild weekend weather ride coming, Autumn storm on the way

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OCTOBER WARMTH

The streak of warm weather has been extended to 11 days.  Friday marked the 11th straight day above normal and the second 80° day of the month. Unseasonably warm air along with high humidity has moved into the state well in advance of a powerful autumn storm out west.  This is summer-level warmth as area temperature continued to rise so did the humidity.  Late Friday the heat index reached 89° at Peru and 86° at Columbus.

Madis_temps

6 PM Friday temperatures

80 in October seems like it’s not all that uncommon, a check of weather records shows 24 of the past 30 October’s have produced a 80° day (2012 did not) but deeper look at the weather record shows that only 9% of the October days have reached 80°.  The official high of 81° Friday marked only the 417th time 80 has been recorded in the month.  We average 2.9 days with 80° temperatures this month – the most 80s in a October: 14 days in 1963.  In 2007, 2 days reached the 90° mark (91° October 8th) setting the latest date of a 90° occurrence for the city.

MASSIVE AUTUMN STORM

It’s a whopper!  The storm that we told you to circle on the calendar for the 5th and 6th has sprung to life right on schedule.  The massive system will drop feet of snow, blizzard conditions and a severe weather outbreak that may include strong tornadoes.  Several states are under winter storm advisories with blizzard warnings in effect for South Dakota and Wyoming where over a foot of snow has already fallen.  Rapid City, SD has reported blinding snow with wind gusts to 68 mph and 19.5″ of snow down.  In the Black Hills and higher elevations of Wyoming snowfall will be measured in feet, possibly over 2 feet in some places.

Satellite_Radar

Radar/Satellite Friday Evening

Winter Advisories

Winter Advisories

SEVERE WEATHER OUTBREAK

The same parent storm will deliver dangerous thunderstorms in the warm sector Friday evening into Saturday morning.  Conditions are very favorable for severe storms, Some of which could produce tornadoes.  Western and Central Iowa along with northeast Nebraska appear to be the target for tornadoes Friday night.

Tornado Ingriedients SREF Fri PM

Forecast Tornado ingredients Friday night

The threat of severe storms will shift east Saturday and include most of Indiana.  Damaging winds look to be the main threat from any severe storms but there are hints that a tornado could develop given the set up in the atmosphere.  The threat of storms will increase later Saturday into Saturday night.  CAPE – a measure of how charged the atmosphere is to support severe storms will peak later in the day.  The forecast suggests that a severe storm can be supported from 2 PM to just after midnight.  We will better nail down the threat in upcoming computer runs.

Severe Outlook

Severe Outlook Saturday

HEAVY RAINFALL

The rainfall numbers are impressive.  We have leaned on the wetter solution all week and now the computers are getting in line with that thinking.  7 Computers average a 1.53″ of rainfall here but amount could vary in and around t-storms.  Some locations could see in excess of 2″ by late Sunday.

Rainfall_Comparison

Rainfall Forecast

The cold front Saturday night will usher in very chilly air for the second day of the weekend.  We will cram 2 seasons into one weekend with a sharp drop coming.  The cold front will pass just before sunrise Sunday and the temperature slide will be well underway.  Plan on wet weather and falling temperatures Sunday, dropping from the middle 60s early into the 50s when the Colts kickoff at 1PM.

The rain threat will diminish but linger into Monday as the cold. upper low spins overhead.  Temperatures Monday and Tuesday morning may dip into the mid to low 40s – coolest officially so far this season.