This week could feature some of the best weather of the entire summer. Cool, dry Canadian air will make for comfortable conditions through Wednesday. Hard to beat dewpoints in the 50s this late in June! Expect a passing thundershower Thursday. Otherwise, dry high pressure may keep rain away for the majority of the 4th of July weekend ahead. Fingers crossed!
The area remains locked under a persistence northwesterly flow aloft. This will continuously channel low dewpoint air into Minnesota. By Thursday, however, a small blip of energy imbedded within this upper level flow will kick off thundershowers Wednesday night - Thursday. Meager moisture amounts along with very little forcing in the atmosphere will result in little rainfall this week. Expecting trails to be in good shape!
Forecast rainfall amounts by Thursday barely top a quarter of an inch...just enough to settle the dust on the singletrack. After Thursday, the next chance of rain MAY be on the 4th of July Monday. Stay tuned.
The main forecast concern for the weekend will be the threat for severe weather Saturday. Comparing Saturday's set up to previous severe outbreaks shows a high probability of significant severe weather that includes tornadoes, destructive hail, and damaging winds.
Those planning on biking Saturday afternoon/evening need to have a way to stay alert of changing weather conditions. Sunday looks like a better day to put some mileage on the bike.
The National Weather Service Storm Prediction Center has the Twin Cities within an "enhanced" risk of severe thunderstorms. This means numerous severe thunderstorms are likely to develop. Saturday morning t-storms will play a factor in the evolution of severe t-storms by the afternoon/evening. Supercell storms are a given. But whether they will be tornadic supercells or a combination of large hail and damaging winds remains a question. Those participating in the Lutsen 99er will be literally racing to the finish to try a beat out the approaching storms from the west.
What is interesting to note is that when looking at the weather pattern for Saturday in comparison to past severe weather outbreaks it is very similar to the June 17, 2010 tornado outbreak in Minnesota.
So far this season Minnesota has experience 19 confirmed tornadoes. The Twin Cities National Weather Service has issued 20 tornado warnings since the first of the year.
Conditions cool down next week. Much more comfortable air in place for biking with highs in the 70s Monday through Wednesday. Long range models hint at 80s for the 4th of July.
With the summer solstice now behind us the hours of daylight begin to slowly wane up until the winter solstice in December. On a brighter note, the next few days will be rather warm and dry. The exception will be Wednesday with showers and thunderstorms.
WeATHER mAP Wednesday
The same front that came through Sunday night and produced thunderstorms across the metro is back. This time as a warm front. This boundary will slowly lift north over Iowa all the while warm, moist air overrides the boundary from south to north to create what's called overrunning precipitation into southern Minnesota.
Generally speaking, the rain from summer-time warm fronts can be heavy. Rainfall totals do indeed close in on an inch near Fairmont. But the precipitation intensity is expected to weaken, even spit over the Twin Cities. As a result the rain totals over the metro trails should stay under a half inch.
Slightly more humid and uncomfortable air arrives Friday and Saturday ahead of the next storm. On Monday that storm was in its early stages of development over the Gulf of Alaska.
Saturday is the next wet day after Wednesday as this Pacific Northwest low nears the Upper Midwest. Expect a modest warm up out ahead of this storms with heat index values once again touching upon the 90s Saturday. Sharp cold front passage by Sunday, however, will send the temperatures crashing back down to much more comfortable levels.
Long range patterns hint at a dry stretch leading up to the 4th of July weekend. The 8-14 Day Precipitation Outlook indicated below normal precipitation June 30 through July 4 across the Minnesota, Midwest, and especially the Great Lakes.
June averages more reports of severe weather than any other month in Minnesota. So far, statewide, ten tornadoes have been reported this month. The average is 12 tornadoes in June. A few (non-severe) storms may rumble through the Twin Cities this weekend. Otherwise, heat and humidity are set to return with at least 95-100 degree heat indices Sunday afternoon.
2016 Severe Storm Reports
Later Saturday night a warm front lifts north over Minnesota generating thunderstorms into Sunday morning. Overall, though, the main storm track remains northwest of the metro.
The airmass behind the warm front will be hot and humid. The hottest day in the extended forecast is Sunday. Cannot rule out a few 100's across far southern Minnesota. Heat-related illnesses can certainly increase in conditions like this. Good idea to refrain from cycling during the peak heating hours of the day...riding either during the early morning hours or evening if possible.
Expect a high chance of a soaking rain over the metro trails Sunday night into Monday as a strong cold front arrives. Considerably cooler air returns with high temperatures trending below normal Tuesday. More comfortable riding weather will be in place by the middle of next week!
Lately when it rains, it pours! The past few rain events have produced 1+ inch amounts. More of the same this week with the Twin Cities being the bullseye of the country for big rain.
Rainfall Forecast Through Thursday
Nocturnal thunderstorms are usually the norm in Minnesota during the warm, summer months. A cluster of heavy rain-producing storms will roll through into Wednesday morning. Rainfall totals could again top 1 inch across the metro.
The possibility of flash flooding is high as the ground remains saturated and unable to absorb much more rain water. The National Weather Service Flash Flood Guidance indicates that Ramsey County would only need 1 inch of rain over a three hour period in order to see flash flooding.
Drier days are ahead, however. Trails will get a chance to firm up Thursday-Sunday as high pressure nudges the storm track northwest of the Twin Cities. After Wednesday, the next chance for a soaking comes late Sunday night.
Piles of small, pea-size hail also covered the ground white in the southwestern suburbs. Higher humidity values through the weekend will likely slow the evaporation process and allow the trails to remain wet for longer than normal.
Our first taste of summer heat and humidity lingers through Sunday. As you take the bike out this weekend it's important to remember to stay hydrated. With dewpoints in the 70s and temperatures in the 90s the body can't cool itself easily. Heat-related illnesses tend to increase in conditions like this. Know the signs.
The excessive heat doesn't last long. Much cooler and more comfortable air arrives next week. Relief comes in the form of a cold front Sunday night-Monday but this front will also produce more rain across our area trails. Be on the lookout for occasional trails closures.
The first taste of true summer heat arrives later this week with temperature 20 degrees above normal. The same hot airmass that broke record highs across the West will begin to surge into Minnesota starting Wednesday. Confidence is high that the area will experience 90-degree heat and high humidity Friday and Saturday. Record highs are certainly possible during that time.
Long range models hint at 100-degrees or better Friday afternoon. I'm not buying it...yet. Thunderstorms may try to develop late in the weekend which could help to subdue the excessive warmth. Rain-cooled, evaporated air has the ability to cool the air down almost 10-20 degrees during summer.
A broad ridge of high pressure settles over the Midwest by Friday. Sinking motion within the atmosphere warms and dries the air. In addition, a southwesterly wind will drag in dewpoints likely exceeding 70 degrees at some point Friday-Saturday. This could easily make it feel like 100 degrees or hotter in the woods and on the singletrack.
Maximum Heat Index Forecast- Saturday
When the weather gets this hot out on the trail it is important to remember heat safety.
Optimal riding weather through the weekend as cool, dry air floods in from Canada. If only the rain would stay away. A few strong storms could develop on Friday as a sharp surface low and its associated fronts pass over Minnesota. This feature will result in lingering light rain Saturday and Sunday. Some areas could even stay in the 60s! Not bad for a time of year when 90-degree heat and high humidity are possible. This year we have an April feel in June.
Surface Map Friday
A surface low is to track across Minnesota on Friday. High enough instability in the atmosphere could create severe thunderstorms. Be on alert if you plan to ride Friday afternoon.
Expect seasonal highs and lows through the first full week in June. In addition, a dry stretch of weather is favored. The 6-10 day precipitation outlook shows a high probability of receiving below normal precipitation. An outlook like this bodes well for off-road riding!
Summer brings warm afternoons perfect for biking, but the summer heat and humidity can also spark thunderstorms and severe weather. Be prepared for any type of adverse weather headed your way with Aeris Pulse.
NWS Twin Cities Weather Story