Thunderstorm chances increase by Saturday evening; Severe weather is possible

Sunday looks quiet

A few spotty showers and an isolated thunderstorm are possible in Minnesota and western Wisconsin into mid afternoon, then thunderstorm chances increase late Saturday afternoon and Saturday evening as a low pressure system pushes into western Minnesota.

At this point, the daylight hours of Sunday look fairly quiet.

Severe weather outlook

The NWS Storm Prediction Center shows a slight risk (shaded yellow) of severe weather across parts of northern Minnesota later Saturday afternoon and Saturday evening:

rt0917d1c
Saturday evening severe weather outlook for Minnesota and Wisconsin
NWS Storm Prediction Center/Twin Cities NWS

Slight risk means that scattered severe thunderstorms are possible. An isolated severe thunderstorm is possible very late this afternoon and this evening in the darker-green shaded area, including the Twin Cities.

You can track showers and thunderstorms on the new interactive radar on the MPR News weather page. You can pan and zoom the radar display on our site to see rain at your location, across all of Minnesota, western Wisconsin and beyond.

Before you keep reading ...

MPR News is made by Members. Gifts from individuals fuel the programs that you and your neighbors rely on. Donate today to power news, analysis, and community conversations for all.

We have updated weather information for Minnesota and western Wisconsin on the Minnesota Public Radio News network, and on the MPR News live weather blog.

Temperature trends

Our average Twin Cities high temperature is 73 degrees this time of year. Saturday afternoon highs will reach the lower 80s in parts of the Twin Cities metro area, southern Minnesota and west-central Wisconsin. Much of Minnesota will have Saturday highs in the 70s, but far northern Minnesota will have highs in the 60s. Dew points will be sticky this Saturday in central and southern Minnesota plus western Wisconsin.

Sunday highs will be mainly in the 70s, with a few 60s in northeastern Minnesota:

rt0918h10
Sunday forecast highs
National Weather Service

Many areas will have Sunday afternoon dew points in the 50s, with sticky 60s in southeastern Minnesota and western Wisconsin:

rt0918h8
Sunday 1 p.m. forecast dew points
National Weather Service

Back to high temperatures, Twin Cities metro area highs are projected to be around 80 degrees on Monday, followed by upper 80s Tuesday, lower 70s Wednesday and lower 60s on Thursday and Friday.

We aren’t expecting extreme heat or cold during the final week of September. The NWS Climate Prediction Center shows a tendency for near-normal temperatures in most of Minnesota and Wisconsin for Sept. 24 through Sept. 30:

rt0917ext
Temperature outlook Sept. 24 through Sept. 30
NWS Climate Prediction Center

Fiona will become a hurricane on Sunday

rt0917sat
Saturday morning satellite loop of Fiona
NOAA

Tropical Storm Fiona is expected to become a hurricane this weekend. A hurricane warning has been issued for Puerto Rico.

Here’s the latest update on Fiona, from the National Hurricane Center:

BULLETIN Tropical Storm Fiona Advisory Number 13 NWS National Hurricane Center Miami FL AL072022 1100 AM AST Sat Sep 17 2022 ...HURRICANE WARNING ISSUED FOR PUERTO RICO... ...HEAVY RAINS LIKELY TO PRODUCE FLOODING AND MUDSLIDES ACROSS PORTIONS OF PUERTO RICO... SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION ----------------------------------------------- LOCATION...16.3N 63.5W ABOUT 130 MI...210 KM SE OF ST. CROIX MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...W OR 275 DEGREES AT 8 MPH...13 KM/H MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: A Hurricane Warning has been issued for Puerto Rico, including Vieques and Culebra. A Hurricane Watch has been issued for the U.S. Virgin Islands. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Hurricane Warning is in effect for... * Puerto Rico, including Vieques and Culebra A Hurricane Watch is in effect for... * U.S. Virgin Islands * South coast of the Dominican Republic from Cabo Engano westward to Cabo Caucedo * North coast of the Dominican Republic from Cabo Engano westward to Puerto Plata A Tropical Storm Warning is in effect for... * Saba and St. Eustatius * St. Maarten * Guadeloupe, St. Barthelemy, and St. Martin * U.S. Virgin Islands * British Virgin Islands * South coast of the Dominican Republic from Cabo Engano westward to Cabo Caucedo * North coast of the Dominican Republic from Cabo Engano westward to Puerto Plata A Tropical Storm Watch is in effect for... * South coast of the Dominican Republic west of Cabo Caucedo to Barahona A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. A warning is typically issued 36 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion. A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours. Interests in the Turks and Caicos Islands and southeastern Bahamas should monitor the progress of Fiona. For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside of the United States, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- Data from Air Force Reserve and NOAA Hurricane Hunter aircraft indicate that Fiona's center has re-formed farther east. At 1100 AM AST (1500 UTC), the center of Tropical Storm Fiona was located near latitude 16.3 North, longitude 63.5 West. Fiona is moving toward the west near 8 mph (13 km/h). A west-northwestward motion at a similar forward speed is expected to begin later today, followed by a turn toward the northwest by Sunday evening. On the forecast track, the center of Fiona is expected to move near or south of the Virgin Islands this evening, approach Puerto Rico tonight, and move near or over Puerto Rico Sunday night. Fiona should then move near the Dominican Republic on Monday. Maximum sustained winds are near 60 mph (95 km/h) with higher gusts. Strengthening is forecast during the next few days, and Fiona is expected to become a hurricane by Sunday or Sunday night while moving near Puerto Rico. Tropical-storm-force winds extend outward up to 125 miles (205 km) from the center. Data from the reconnaissance aircraft indicate that the minimum central pressure is 1004 mb (29.65 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Tropical Storm Fiona can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT2 and WMO header WTNT42 KNHC and on the web at hurricanes.gov/text/MIATCDAT2.shtml. WIND: Hurricane conditions are expected on Puerto Rico Sunday and Sunday night and are possible in the U.S. Virgin Islands tonight. Hurricane conditions are possible within the hurricane watch area in the Dominican Republic Sunday night and Monday. Tropical storm conditions will continue across portions of the Leeward Islands within the warning area through this afternoon. Tropical storm conditions will reach the U.S. and British Virgin Islands this afternoon, spread westward across Puerto Rico tonight, and reach portions of the Dominican Republic Sunday night. Tropical storm conditions are possible across the watch area in the Dominican Republic Sunday night. RAINFALL: Fiona is forecast to produce the following rainfall: Leeward Islands and Northern Windward Islands: Additional 2 to 4 inches. British and U.S. Virgin Islands: 4 to 6 inches with local maximum of 10 inches possible. Puerto Rico: 12 to 16 inches with local maximum of 20 inches possible, particularly across eastern and southern Puerto Rico. Dominican Republic: 4 to 8 inches with local maximum of 12 inches possible, particularly on the far eastern coast. Haiti: 1 to 3 inches with isolated maximum totals of 4 inches. Turks and Caicos: 4 to 6 inches. These rains are likely to produce flash and urban flooding, along with mudslides in areas of higher terrain, particularly southern and eastern Puerto Rico and the eastern Dominican Republic. STORM SURGE: The combination of storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas in areas of onshore winds if the peak surge occurs at the time of high tide... Southern coast of Puerto Rico...1 to 3 ft Vieques and Culebra...1 to 3 ft U.S. Virgin Islands...1 to 2 ft Localized coastal flooding is also possible elsewhere in Puerto Rico. For information specific to your area, please see products issued by your local National Weather Service forecast office. Storm surge will raise water levels by as much as 1 to 3 feet above normal tide levels along the immediate coast in areas of onshore winds in the Dominican Republic. SURF: Swells generated by Fiona are affecting the Leeward Islands, the northern Windward Islands, the Virgin Islands, Puerto Rico, the northern coast of the Dominican Republic, the Turks and Caicos Islands, and the southeastern Bahamas. These conditions could cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

Here’s the forecast track of Fiona, including the cone of uncertainty for the path of Fiona’s center:

rt0917track
Forecast track of Fiona
NWS National Hurricane Center

The National Hurricane Center will issue several Fiona updates today and through the coming days.

Weather nugget

So far this year, precipitation at International Falls is running one foot above normal. Precipitation is rainfall plus the water content of the snow that fell earlier this year. Duluth precipitation is running 2.11 inches above normal, and Twin Cities precipitation (measured at MSP airport) is 6.42 inches below normal so far this year.

Programming note

You can hear my live weather updates on MPR News at 7:35 a.m., 9:35 a.m. and 4:39 p.m. Saturday and Sunday.