Geomagnetic storm triggers auroras; 70s return this week

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If you were awake and looking upwards overnight you may have witnessed a sky show last night. A strong (G3) geomagnetic storm triggered vivid auroras across the northern Great Lakes Monday night. Green curtains of Northern light waves flashed from upstate New York to Minnesota.

The culprit? Sunspot AR 2741.

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The planetary K Index reached high levels overnight as the solar particles bombarded earth's atmosphere.

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The solar storm pushed the visible auroral oval all the way south to northern Minnesota.

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NOAA has issued a geomagnetic storm watch for the possibility of more auroras tonight.

The G1 (Minor) geomagnetic storm watch is now in effect for both 15 and 16 May, 2019 (UTC-days) due to anticipated CME effects.

A series of three observed Coronal Mass Ejections (CMEs) have taken place since 10 May, 2019. The first two CME events are expected to arrive on 15 May and the third CME is anticipated to arrive the later half of 16 May.

The source location for the CME's has been associated with disappearing solar filaments (DSF) along areas of the magnetic neutral line in the vicinity of the unipolar sunspot group, Region 2741.

Arrival times for any geoeffective components of these CMEs have a level of uncertainty; however, most model runs are in agreement and the consensus holds for 15 and 16 May arrivals.

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Stay tuned and keep looking up.

Milder week arrives

A few spotty showers may dot the Doppler late this afternoon and evening as a fading front sags south across Minnesota. Temperatures rise into the 70s this week. The Twin Cities peaks around 80 degrees with humidity Thursday afternoon.

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NOAA via Weather Bell.

Wet weekend

Rain and thunder chances increase Friday night through Sunday. The National Oceanic and Atmospheric Administration's Global Forecast System model is typical of model solutions that favor waves of rain and thunder this weekend.

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NOAA GFS model Friday into Sunday via tropical tidbits.

A surge of Gulf moisture could drive dew points into the sticky 60s by Sunday.

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NOAA GFS model dew point forecast for 1 pm CDT Sunday via tropical tidbits.

NOAA's GFS model has been cranking out widespread 2 to 4 inches-plus rainfall totals over the upcoming weekend. With dew points in the 60s to near 70 and multiple storms waves, we could see those kinds of rainfall totals locally.

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NOAA GFS model rainfall output through Sunday via pivotal weather.

Enjoy the milder week and stay tuned as we tweak the potentially wet weekend forecast.