Thursday, April 18, 2019  3:05 AM

Southern Storm Takeover Means We Begin to Dry Late Today

Rain and Thunderstorms Increase Flooding Problems in Twin Cities and Minnesota River Valley

Rain and thunderstorms dominated the weather in much of Minnesota yesterday. The thunderstorms were the heaviest during the morning and midday, especially in south central and east central Minnesota. While there were a couple of large hail reports, the primary form of severe weather was heavy rain between the Twin Cities on the north side and Mankato and Rochester on the south side. These conditions are still affecting some roads south of the Twin Cities early this morning. US 169 between St. Peter and Mankato is closed due to a mudslide and Minnesota River crossings near Henderson are closed once again.

Moisture Supply Being Interrupted by Severe Weather Producing Texas Storm

The main batch of rain and thunderstorms has now moved on to Michigan and Ontario (see satellite loop from Colorado State satellite slider), but there are a lot of low clouds persisting with a few scattered rain showers over North Dakota and northern Minnesota (see NWS Upper Mississippi Valley radar). This storm has seen its area of rainfall shrink because a second storm system over the Texas Panhandle (see Mid-Tropospheric water vapor loop from Colorado State satellite slider menu) triggered much stronger showers and thunderstorms yesterday afternoon and overnight from Texas into Oklahoma, Kansas, Missouri, and Arkansas. There were several reports of severe weather from the Texas Panhandle through Kansas in the early evening storms. The line of strong thunderstorms moving across central Texas in the early morning hours has produced some large hail and high winds.

Lingering Rain and Drizzle This AM, Few Showers PM

In Minnesota, we still need to get past the upper-level storm system (see counterclockwise circulation over the eastern Dakotas on the Mid-Tropospheric water vapor loop). While the warm and sticky air supply to this system has been cut off by the Texas storm, our low will be able to squeeze out some more scattered light rain showers or drizzle today. The best chance for persistent rain or drizzle will be this morning. Slightly drier air will work its way in this afternoon, but there still will be enough lingering moisture to produce a few scattered rain showers this afternoon. There could even be a thunderstorm or two. Because we won't dry out quite as quickly as I had thought earlier in the week, I'm lowering my high temperature range to the middle 50's today. Readings will likely stay in the 40's this morning with the persistent rain or drizzle, then climb over 50 this afternoon. The northwest winds seen early this morning (see NWS Aviation Weather Center METAR map) will increase back to the 15-25 MPH range with a few higher gusts possible (see NWS Minnesota Hourly Weather Round-Up).

Drying Begins Tonight....

This combination storm will slowly move through the Tennessee and Ohio River Valleys today and reach the East Coast tomorrow, producing more heavy rainfall and a pretty good chance for severe weather in the Gulf Coast today and from Virginia to north Florida tomorrow. However, as that storm limps eastward, it should get far enough to our east to allow the drier air in Alberta, Montana, and western Nebraska to move in. Skies will clear out late this afternoon or early this evening. The strong northwest winds will calm down after midnight, so low temperatures will fall back to the middle 30's. The wet grounds and light winds will allow some areas of dense fog to form by tomorrow morning.

...Allowing Spring-y Highs Friday Through Monday (First 70 Saturday?)

However, once a full day of sunshine begins to work on the seasonably mild air we still have, high temperatures will return to the 60's tomorrow. On Saturday, St. Cloud will have the opportunity to join the cities and towns that have already hit 70 degrees so far this spring. St. Cloud's average first 70-degree high of the spring occurs on April 17.

We won't be able to hold on to 70-degree weather for more than a day, as a cold front will push through Saturday evening. However, the much drier air that will take over beginning tomorrow means that there will only be a chance of a few scattered showers late Saturday afternoon or early Saturday evening. Sunshine will return on Sunday. Temperatures will be 10-15 degrees cooler than on Saturday, but that still means a high around 60 or a bit above, which is a lot more pleasant than yesterday.

The overall weather pattern continues to produce a chance of some slow moving storms in the Plains intensifying as they hit the Mississippi Valley. If we get hit by one of these systems, there could be more heavy rainfall that we don't need. On the other hand, if they track far enough to our south or east, we could be in the sunshine with temperatures at least seasonably warm or even warmer for mid-April. There still are no signs of really cold air for the next week. So, any chilly day we'd have will be like today and yesterday: when there are a lot of clouds and rain.

Still Some Achy Weather in Pressure Changes Today

The low pressure area over Wisconsin will ease off to the east today. There continues to be a major pressure difference between the low and the higher pressure in the Dakotas (3 red lines or isobars touching Minnesota in the early morning hours), so there will be enough of a pressure difference to keep conditions breezy today and continue to bother those people with joints or arthritis sensitive to pressure changes. These conditions will ease this afternoon and end tonight.

Minnesota, Red, Mississippi River Levels Rising or to Rise Within Next Few Days

The heavy rainfall will aggravate the snowmelt condition in the Minnesota River Valley. Places like Morton and Montevideo will return to major flood stage today. The second peak in river levels could be even higher than forecast from Mankato to the Twin Cities (some of the reporting stations, like Henderson, are showing slightly higher river levels than what was forecast from yesterday's midday computer run). Downstream, both St. Paul and Hastings are expected to reach major flood stage by the middle of next week.

Near the source of the Red River, Hwy. 12 is now closed outside of Ortonville due to flooding (see MnDOT road reports). The major snowmelt from early this week is about to push the Red River back to major flood stage in Fargo and Grand Forks with prolonged major flooding expected further to the north along the Minnesota-North Dakota border. Several bridges are closed and will likely remain closed for quite a while.

Along the Upper Mississippi River, Aitkin and Fort Ripley are being pushed back to at least minor flooding and St. Cloud is now forecast to have water a bit out of its banks in the next couple of days. The Sauk River is forecast to near flood stage in the next few days, so minor flooding may be possible.

Oops...No Reschedule of Tornado Drill

Unlike what I've put in this space earlier in the week, the Minnesota statewide tornado drill that was cancelled in our snow and sleet storm last week has not been rescheduled. See the Minnesota Division of Homeland Security and Emergency Management for further updates and links to the warm season severe weather safety information.

Confidence Level: "The Bulb on That Hard-To-Reach Light in the Foyer Will Burn Out"

Thursday 4/18/2019: Mostly cloudy with morning steady light rain or drizzle. Occasional showers and a slight chance of a thunderstorm in the afternoon. Windy, but not quite as cool as yesterday. High: between 52 and 57. Winds: NW 15-25 MPH with higher gusts. Chance of measurable rainfall: 60%.

Thursday Night: Clearing with slowly diminishing wind and cooler. Maybe some fog by morning. Low: between 32 and 37. Winds: N 8-15 MPH evening, NW 5 MPH late at night. Chance of measurable rainfall: 10%.

Friday 4/19/2019: Sunny, less windy, seasonably mild and drier. High: between 57 and 63. Winds: NW 5-15 MPH. Chance of measurable rainfall: 10%.

Friday Night: Partly clear, a bit breezy, and not quite as cool. Low: between 42 and 46. Winds: S 8-15 MPH. Chance of measurable rainfall: 10%.

Confidence Level: "Every Time I Try to Put in a New Bulb, the Light Fixture Will Try to Detach From the Ceiling"

Saturday 4/20/2019: Sunshine through high clouds, breezy, and much warmer. A slight chance of a rain shower late. High: between 70 and 75. Winds: SW 10-20 MPH. Chance of measurable rainfall: 20%.

Saturday Night: A chance of an evening shower, then partial clearing, breezy, and drier. Low: between 42 and 48. Winds: NE 10-20 MPH. Chance of measurable rainfall: 30%.

Sunday 4/21/2019: Sunshine through high clouds and not quite as warm. High: between 58 and 63. Winds: NE 5-15 MPH. Chance of measurable rainfall: 10%.

Sunday Night: Partly clear, breezy, and a bit cooler. Low: between 40 and 45. Winds: N 5-10 MPH. Chance of measurable rainfall: 10%.

Monday 4/22/2019: Sunny and springlike. High: between 62 and 67. Winds: N 5-15 MPH. Chance of measurable rainfall: 10%.

Confidence Level: "The Only Way I'll Be Able to Change the Bulb and Hold the Fixture in Place Will Be to Yell At It

Extended: Chance of rain showers Saturday night. Not quite as warm on Sunday.

Forecast Confidence (10 - "The Rabbits Will Thump, Objecting to Me Yelling at the Light Bulb"; 0 - "I Will Be Hosting a DIY Show on Home Repairs"): 7 Monday through Tuesday, 6 Tuesday night, 5 Wednesday and Wednesday night, 4 Thursday, 3 Thursday night and Friday, 2 Weekend.

Yesterday's High: 51°F; Overnight Low (through 3 AM Thursday): 40°F
St. Cloud Airport Total Storm Precipitation (through 3 AM Thursday): 0.82 inch; SCSU Precipitation (through 3 AM Thursday): TBA

Next Update: Friday, April 19, 2019 8 AM (or as needed)

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