No change in the outlook as much colder air will dump out of the Polar Region through the next week or so; beginning this weekend. There will be the risk of a frost, freeze and even rain/snow showers with the abrupt change in the jet stream. Frost and freezes will greatly depend on sky and wind conditions as the atmosphere will certainly be cold enough at some junctures to support it.
October has been mainly a beautiful warm month thus far across much of the Great Lakes region including Southeast Lower Michigan. Temperatures across Southeast Lower Michigan thus far in October will have averaged a good 7 to 9 degrees above normal by the end of this weekend; but this will change come later next week. Colder air of Polar origin has been charging up across that region and indications have been for several days now it will begin to trek south by this upcoming mid-late week period /16-18th/ toward the Lakes. All indications show a cross polar dive of cold air into the eastern half of North America as ridging builds over the west, This change has been intimated for days in the NAO into next week with a dive into negative territory.
This first wave of cooler air will arrive mid week and be accompanied by showers and possibly a few thunderstorms later Tuesday into Wednesday. After this, the drop temperatures will fall back closer to more typical October readings for mid month across all of Southeast Lower Michigan; mid 50s to near 60 for highs and mid 30s to lower 40s for lows.
The real interesting colder shot of air is slated to arrive on heels of the first by Friday into next weekend (18 -19th) with a re-enforcing shot later over the weekend. This cold air will likely bring our first widespread frost and/or freeze depending on air coldness, sky and wind conditions. Therefore, this is a heads up on a widespread frost/freeze risk for Southeast Lower Michigan! There is even the chance of some snow showers with this system if projections hold true to form.
Note; I said interesting shot of colder air next weekend for another reason; one of meteorological models has been insisting on developing a brute of an October storm over next weekend on the tail end of the second wave of colder air. The general storm track of this system has been from the Lower Mississippi Valley /Arkansas area/ to the Eastern Lakes region /SE Mich/SW Ontario area/ the last few runs (see below). Earlier, it developed this storm track further west over the southern Midwest to eastern Upper Michigan. This will have to be watched to see if this is a figment of the Euro's imagination or not; at this time the development and strength of this system looks quite suspect, however the Euro tends to be the better models for later periods! We shall see...
In any event, the third week of October does not look nearly as nice as the first two weeks. As this radical change in our weather pattern develops; I'll update this outlook.
Looking back over the past decade or so, here are many October cold blasts I wrote about....
Just last October 2012
10/8 Update; A Cold and Frosty Columbus Day Greets Inhabitants of Southeast Lower Michigan
The most dismal weather seemed to come at the peak autumn color show across the region. No doubt the worst of weather in October (and likely the fall) came mid-month on the 12th with a record breaking cold blast of Arctic air. The storm had an uncanny resemblance to very old record setting storm itself, back on October 13th, 1909. Both systems contained impressively deep centers / around 29.00”/ and air straight out of cold core depths of the Arctic. They also took similar tracks and blasted same region with heavy snow, lake effect snow and again, exceptional cold for October. Blustery heavy snow showers bombarded the land with visibilities, at times, dropping to white out conditions.
Then in OCTOBER 2004
NEAR RECORD COLD FIRST WEEK OFFSET BY INDIAN SUMMER WEATHER THE LAST WEEK
October opened in the depths of some of the unseasonably cold air that arrived late in September. A strong polar high pressure pushed the cold air south into the area from Northern Canada. So cold was it on the 1st, that several locations noted snow flakes mixed in with rain showers. While that was the case here at the NWS in White Lake, it was not officially at Detroit Metro Airport. If snow had been observed there, it would have tied the earliest date for snowfall officially observed at Detroit /Oct 1st 1974/. The chill hung around for the nearly the entire first week of the month. High temperatures held down in the 50s, while lows fell into the upper 20s to upper 30s.
OCTOBER OF 2002
WILL BE REMEMBERED ACROSS SOUTHEAST LOWER MICHIGAN FOR ITS NOTABLE CONTRASTING TEMPERATURE PATTERN. THE MONTH ARRIVED LIKE SEPTEMBER ENDED WITH UNSEASONABLY WARM WEATHER PRODUCING RECORD OR NEAR RECORD WARMTH. A HIGH TEMPERATURE AT DETROIT METRO AIRPORT OF 86 ON THE 1ST CAME WITHIN 2 DEGREES OF THE RECORD /88/. THAT HIGH OF 86 CHALLENGED BUT WAS UNABLE TO BREAK THE RECORD HIGH THAT CONTINUES TO STAND FOR OVER A CENTURY...SET WAY BACK IN 1897. THE LOW OF 66 AND AVERAGE TEMPERATURE OF 76 WERE...HOWEVER...THE WARMEST TEMPERATURES EVER SEEN ON OCTOBER 1ST. ANOTHER HIGH IN THE 80S /81/ CAME ON THE 4TH AND WAS A GOOD 15 DEGREES ABOVE NORMAL. THE SUMMER-LIKE WEATHER WITH TEMPERATURES IN THE 80S WAS ENDED ON THE 4TH BY A STRONG COLD FRONT THAT CHURNED-UP A SQUALL-LINE OF SHOWERS AND WIND GUSTS UP TO AROUND 45 MPH.
BIG CHANGE CAME MID MONTH AS THE UPPER WIND PATTERN SHIFTED FROM A DOMINANT SOUTHWESTERLY FLOW TO NORTHWESTERLY. THE COLDER SECOND HALF OF OCTOBER CAUSED THE AVERAGE TEMPERATURE TO DROP OVER TEN DEGREES TO 50 DEGREES BY MONTH'S END! THE WELL ABOVE NORMAL COOLING DEGREE DEPARTURE FOR THE MONTH...DESPITE THE BELOW NORMAL MONTHLY AVERAGE TEMPERATURE...FURTHER UNDERLINES THE CONTRASTING TEMPERATURE PATTERN OF THE MONTH. IN SPITE OF THE COLDER SECOND HALF OF OCTOBER...NO RECORD LOWS WERE SET. FROST AND FREEZES DID...HOWEVER...PRETTY MUCH ARRIVE ON SCHEDULE ACROSS SOUTHEAST LOWER MICHIGAN BY MID MONTH. THE FIRST FREEZING TEMPERATURE /30 DEGREES/ AT DETROIT METRO AIRPORT WAS RECORDED ON THE 14TH.
Making weather fun while we all learn,
Bill Deedler - SEMI_WeatherHistorian