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The most important weather forecast ever?

Today we honor the brave American soldiers who stormed the beaches of Normandy 65 years ago today, ultimately turning the tide of WWII and freeing Europe from Nazi fascism. The Operation Overlord invasion resulted in an unimaginable loss of life, over 10,000 American, British and Canadian troops died on the first day of the battle; nearly 9,000 ships manned by 195,000 soldiers from eight allied nations came ashore on that bloody, miserable day.

By all accounts the invasion caught the German High Command off guard. High winds, heavy rain ruled out an all-out allied assault in early June of ’44; Hitler’s generals were convinced that the foul weather would deter General Dwight Eisenhower from pulling the trigger anytime soon. They relied on a team of German meteorologists, who confirmed that the storm would continue, no let-up in sight. After delaying Operation Overlord by one day because of foul, wind-whipped weather conditions in the English Channel, Eisenhower turned to his own meteorologist, who had a different take on the forecast. After careful analysis the weatherman went out on a limb and made the boldest prediction of his life. His take on the situation: there would be a brief lull in the storm, winds would diminish just enough to launch the ships, the rain would ease and skies would brighten. Eisenhower took this into consideration before issuing the final order to commence the D-Day invasion on the morning of June 6, 1944. Sure enough, the storm weakened, the rain stopped, and winds dropped off just enough to get troops onto the beaches.

There have been numerous examples throughout history where the weather has had a profound impact on the outcome of battles and the ultimate outcome of war. An especially severe winter stopped Hitler’s troops in their tracks as they marched toward Moscow. Torrential rain in Vietnam impaired American bombing runs, making accurate targeting all but impossible. Most recently ‘Storming Norman Schwarzkopf Jr relied on American military meteorologists to launch the attack on Baghdad during a period with no dust storms or extreme heat. But the D-Day forecast has always left me dumbfounded, amazed – and grateful. When I flub a forecast barbecues get rained out, people become irate, it’s an inconvenience, yes. But I try to put myself into the shoes of the meteorologist who had to brief General Eisenhower on June 5, confident enough in his forecasting abilities to make what is in all probability the most critical weather prediction of the 20th century, one that caught the Germans flat-footed, and helped to ultimately turn the tide of history.

For more on D-Day and the weather complications that impacted Operation Overlord, click here.

After the third driest May on record for much of Minnesota the weather pattern finally seems to be shifting gears. Last week significant storms consistently tracked well south of Minnesota, but the frontal boundary separating summer-like air to the south from unusually chilly air draped over the northern tier states will set up directly over our heads. A series of storms rippling east along this stagnant front will result in several opportunities for some much-needed rain. The best chance of a good soaking will come today, again on Monday, when a few T-storms may rumble across the southeastern third of Minnesota – a few could even turn severe due to strong wind shear aloft and ample moisture near the ground.

It’s tough trying to pin down where (precisely) the heaviest bands of rain will set up with this next storm swirling out of the Rockies. The models have been keeping the 1″+ rainfall amounts over far southern Minnesota, but a 50-75 mile shift to the north would put the heaviest rains very close to the Twin Cities and St. Cloud. The chance of rain increases this morning, and a half inch or more of liquid goodness may accumulate in rain gauges by late afternoon. The cold rain (yes, temperatures hold in the 50s….is this REALLY June 6?) lets up by the dinner hour, you may be able to salvage outdoor plans this evening, but the ground will be wet and muddy. Be careful out there.

Sunday looks marginally better, skies brighten a bit with drizzle and a few light showers during the day. It will be a few degrees “milder”, but still at least 15 degrees cooler than average for this date. Thunderstorms may flare up over Iowa and South Dakota and rumble across the southern third of Minnesota late Sunday and Sunday night. SPC, the Storm Prediction Center, has the southeastern third of Minnesota in a slight severe risk Monday. Some very unstable, turbulent air will set up just to our south, and a few storms from Mankato to Rochester may pack large hail and potentially violent winds. Another .5 to 1″ of rain may fall Monday, before we finally dry out a bit by the middle of next week. A very cool start to the week gives way to a slow warming trend the latter half of the week (back into the 70s). Long-range guidance is still teasing us with 80s returning by Tuesday, June 16, give or take a day. It WILL warm up, within a couple of weeks dazed neighbors (who don’t know any better) will be whining about the heat and humidity. Count on it.

But today will feel more like early April than early June. A charcoal-gray sky, a damp east wind gusting to 20 will make that 55-57 degree “high” feel more like 40s. Throw in a hard rain by midday and you have all the ingredients for a great movie/shopping/errand kind of day. Repeat after me “we need the rain.” Let it be your weekend mantra. Odds are you’ll hear that phrase at least a half dozen times between now and Monday. It’s true, of course, moderate to severe drought conditions linger over much of southeastern and central Minnesota, so it’s hard to get overly indignant about rain, even on a (precious) weekend. It could be worse: a few days ago some of the computer guidance was hinting at temperatures aloft being just cold enough for a few wet snowflakes up in the Red River Valley by Monday. The risk of snow has diminished (thank God) but parts of Montana and Wyoming may pick up a few inches of slushy snow from the same system that’s leaking rain on our heads. I still find this amazing & baffling. A little more than 2 weeks from the Summer Solstice and there are still snow advisories over the northern Rockies! I don’t know whether to laugh or weep.

The good news: check out the swath of significant rain predicted for the next 5 days, centered over southeastern MN and much of Wisconsin. Rainfall amounts drop off as you head north of St. Cloud and Mille Lacs, but this is the wettest QPF (quantitave precipitation forecast) I’ve seen in over 3 weeks. Note: the QPF tends to over-predict rainfall amounts, it’s the trends that are important. For the very latest 5-Day rainfall prediction for the USA click here.

O.K. In the spirit of full disclosure here’s the bad news: these are the predicted HIGHS for today, not the lows. Really! It will look and feel more like early/mid April out there than early June. Skip the sunscreen, save some cold cash on air conditioning (in fact you probably shouldn’t be surprised if you hear the furnace kick on). Good grief….

This is the severe storm outlook for Monday, from SPC in Norman, Oklahoma. Even though surface temperatures will be unseasonably cool (50s to low 60s) there may be just enough wind shear (changing wind direction/speed with altitude) and instability available, with a vigorous warm front draped just to our south to spark a few isolated severe storm cells by Monday afternoon. As is always the case any large, damaging hail or violent winds will affect a tiny percentage of the state. Most of us will see heavy rain, possibly a gusty thunderstorm – there’s just no way to predict, this far in advance, which counties may see severe weather. For the very latest severe weather updates from SPC click here.

Yes, “we need the rain, you know.” No kidding. The southern half of Minnesota is too dry. For the record it would take anywhere from 1.5 to 3.25″ of rain to pull east central and southeastern MN from the current drought. Yes, we do need the rain. The lousy timing is unfortunate, but there’s not much we can do about that. To check out the latest Drought Monitor map click here.

Weather Headlines:

* 74 degree high on Friday in the Twin Cities. Average high for June 6 is 77.

* Temperatures today: 20 degrees below normal, holding in the 50s, east wind 10-15+.

* Half an inch or more of rain possible today, wettest period from 9 am to 4 pm.

* Drier Sunday, skies try to brighten up (a little). Ripe for drizzle, highs near 60.

* A round of heavy thunderstorms possible Sunday night into Monday morning, computers hinting at another .50 to 1″ of rain.

* Slight severe storm risk Monday includes Twin Cities and the rest of southeastern MN.

* Unseasonably cool weather early next week, slowly warming as the week goes on.

* Early word for the second weekend of June? Milder, but potentially ripe for showers/T-storms.

* Weekend rain may ease drought (and “extreme” wildfire threat) across the metro area.

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