Sunday, June 7, 2009

Monday Soaking

Plan on leaving early for work Monday, because the weather promises to be extremely soggy and messy, with standing water on area highways, even a potential for some minor flash flooding. The very latest computer models are printing out anywhere from 2.3 to 2.6" of rain by Monday evening. The heaviest rains will probably come during the morning and midday hours Monday, possibly accompanied by lightning and thunder, although the potential for severe weather is quite small (except for far southeastern MN and counties along the MN/Iowa border, where we can't rule out large hail and damaging winds in a few of the storms).

Most of us will just see window-rattling, gulley-gushing, torrential rains. If the models are on the right track (and right now there does seem to be continuity/agreement between the NAM, predicting 2.3" and the WRF, predicting closer to 2.6") then many of us will wind up receiving 2 weeks worth of rain in one day. Obviously much of this rainwater won't have a chance to soak into the ground, where it's needed, but rather run-off into streets, streams and storm sewers. If you routinely struggle with a wet basement, or live next to an intersection that floods, or a small stream that often jumps out of its bank, be alert tomorrow - if this forecast verifies I have a hunch there may be some flash flood warnings issued.

The heaviest rains should be winding down by 2-3 pm, shifting north toward Duluth, so you may be able to salvage late afternoon and evening plans, in spite of lingering mud and muck. The rest of the week looks fairly dry, culminating in a MUCH nicer spell of weather next weekend, when temperatures will be well into the 70s with some badly-needed sun both days. But today your drip-dries will be drooping. Look at the bright side: I seriously doubt you'll have to water the lawn or garden anytime soon.

Weather Headlines

* 52 degree high at St. Cloud and the Twin Cities Saturday. Average high is 77, average low is 55 for June 6.

* Yesterday MAY have been the coolest June 6 since 1891 for much of central and southern Minnesota. Rochester's 55 degree high broke a record for the coolest high temperature for June 6.

* Just drizzle today, but clouds linger, temperatures hold in the 50s most of the day.

* More rain arrives tonight and lingers Monday morning, another 1 to 1.5" of rain possible.

* Slower commute likely tomorrow morning with standing water on the roads - leave extra time.

* Basically dry from Tuesday through Thursday with slowly mellowing temperatures, 70s return by Thursday.

* More showers/thunder possible Friday into early Saturday.

* Early word on next weekend: BETTER! Ample sun from midday Sun through much of Sunday with highs in the mid to upper 70s, closer to average.

Saturday's high temperatures around the USA. Click on the graphic to bring it full-screen. Image courtesy of Plymouth State Weather Center, a great source of current/predicted weather maps.

75 hour precipitation forecast for the Upper Midwest, showing another 1-2" of rain for much of Minnesota, most of it falling from late Sunday night through midday Monday. Note the graphic in the upper right, showing a couple inches of SNOW for western North Dakota. Forecast map courtesy of Click on the image to bring it full-screen.

So who - or what - do we blame for this spell of unseasonably, UNREASONABLY cool weather? Is there an atmospheric smoking gun, or do we just chalk this up to random atmospheric variability? Probably the latter. The jet stream has more of a northwesterly component than we should be seeing in early June, when winds aloft historically howl from the southwest. Could it be a symptom of what's happening on the sun (fewest sunspots since 1928?) Possibly. The graphic below shows a mild El Nino (warming) of equatorial Pacific Ocean water developing. If this trend continues and strengthens, with sea surface temperatures 2-4 degrees F warmer than average (a strong El Nino) then, statistically, that would tend to favor a milder autumn and winter for the northern 2/3rd's of America, with wetter, cooler weather for much of the south. I'm not yet ready to crawl out onto that shaky limb, but I don't think we can point to anomalies in the Pacific for a clue as to why we're walking the streets in jackets during the first week of June. By the way, CPC, the Climate Prediction Center, is predicting a cooler than normal June for Minnesota and the Dakotas, which seems like a pretty good bet, based on how the pattern is setting up. Next week will be 5-10 degrees below average in the temperature department, but by the weekend we should be clawing back up to "normal", whatever that is.

Latest sea surface temperatures, showing a mild El Nino event brewing in the Pacific. To check on the latest status click here for NOAA's El Nino Page.

Paul's Outlook

Today: Cloudy, cool and damp with little more than patchy drizzle. Winds: East/Northeast 10-15. High: 59

Tonight: Rain developing, potentially heavy late. Low: 51

Monday: Rain, heavy at times during the morning. Drying out by afternoon with partial clearing possible later in the day. High: 58

Tuesday: Partly sunny, a big step in the right direction. High: 66

Wednesday: Intervals of sun, hints of spring fever return. High: 69

Thursday: Plenty of mild sunshine. High: 74

Friday: More clouds, unsettled, passing shower or T-storm. High: 75

Saturday: Potentially wet start, then afternoon sunshine. High: 74

Sunday: Sun fading late, warmer. High: 78

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