Steamy Saturday, with some showers/thunderstorms at times

Our average Twin Cities high temp is 83 degrees this time of year. We’re looking at metro area highs in the upper 80s to around 90 Saturday afternoon.  Parts of southern Minnesota and west-central Wisconsin could reach the lower 90s, with 80s in central and northern Minnesota.

Dew points will be in the steamy 70s in most areas. Due to our combination of hot temperatures and high dew points, the National Weather Service has issued an excessive heat warning for the Twin Cities metro area until 8 p.m. this Saturday, with a heat advisory across much of the southern half of Minnesota and into west-central and southwestern Wisconsin:

Here are details of the excessive heat warning in the Twin Cities:

URGENT - WEATHER MESSAGE National Weather Service Twin Cities/Chanhassen MN 639 AM CDT Sat Jul 25 2020 MNZ060>063-068>070-252000- /O.CON.KMPX.EH.W.0003.000000T0000Z-200726T0100Z/ Hennepin-Anoka-Ramsey-Washington-Carver-Scott-Dakota- Including the cities of Minneapolis, Blaine, St Paul, Stillwater, Chanhassen, Chaska, Victoria, Shakopee, and Hastings 639 AM CDT Sat Jul 25 2020 ...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM CDT THIS EVENING... * WHAT...Dangerously hot conditions with heat index values up to 103. * WHERE...Scott, Carver, Washington, Ramsey, Anoka, Hennepin and Dakota Counties. * WHEN...Until 8 PM CDT this evening. * IMPACTS...Extreme heat and humidity will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities. PRECAUTIONARY/PREPAREDNESS ACTIONS... Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Young children and pets should never be left unattended in vehicles under any circumstances. Take extra precautions if you work or spend time outside. When possible reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear lightweight and loose fitting clothing when possible. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.

Here are some of the peak heat index values that are forecast for Saturday afternoon:

Note the NWS statement about cloud cover, and how it may affect heat index values in some areas.

Thunderstorm chances

Minnesota and western Wisconsin will have areas of rain and some embedded thunderstorms this Saturday and Saturday night. Most locations will also have some rain-free hours.

The National Weather Service Storm Prediction Center shows a marginal risk of severe weather in Minnesota and western Wisconsin this Saturday and Saturday night:

Marginal risk indicates that an isolated severe thunderstorm is possible. The Storm Prediction Center will update the severe weather outlook later this morning and this afternoon.

You can hear updated weather information on the MPR network, and you’ll see updated weather info on the MPR News live weather blog.

The Twin Cities metro area, far southern Minnesota and western Wisconsin could see a few scattered showers and thunderstorms Sunday morning and early Sunday afternoon.

Temperature trends

Highs in the 70s are expected over most of the northwestern half of Minnesota on Sunday, with 80s elsewhere:

Drier dew points will spread over the cooler area, with steamy 70s lingering into Sunday afternoon in the southeast:

Back to high temperatures, Twin Cities metro area highs are projected to reach the lower 80s on Monday and Tuesday, followed by mid 80s Wednesday, Thursday and Friday.

Hurricane Hanna

Hurricane Hanna was moving toward the south Texas coast Saturday morning….here’s the Saturday morning radar loop:

Here’s the forecast track for the center of Hurricane Hanna, along with the cone of uncertainty:

Updates on Hurricane Hanna will be posted every few hours by the National Hurricane Center.

Hurricane Douglas moves closer to Hawaii

Hurricane Douglas has max sustained winds of 105 mph, and is tracking toward Hawaii.

Here’s the forecast track for the center of Hurricane Douglas, along with the cone of uncertainty for the track:

These are the latest Hurricane Douglas details, from the Central Pacific Hurricane Center in Honolulu:

BULLETIN Hurricane Douglas Advisory Number 21 NWS Central Pacific Hurricane Center Honolulu HI EP082020 500 AM HST Sat Jul 25 2020 ...HURRICANE DOUGLAS CONTINUES TO MOVE WEST-NORTHWEST TOWARD HAWAII... ...TROPICAL STORM WATCH ISSUED FOR KAUAI COUNTY... SUMMARY OF 500 AM HST...1500 UTC...INFORMATION ---------------------------------------------- LOCATION...19.1N 148.4W ABOUT 440 MI...705 KM E OF HILO HAWAII ABOUT 635 MI...1020 KM ESE OF HONOLULU HAWAII MAXIMUM SUSTAINED WINDS...105 MPH...165 KM/H PRESENT MOVEMENT...WNW OR 290 DEGREES AT 18 MPH...30 KM/H MINIMUM CENTRAL PRESSURE...975 MB...28.80 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY... A Tropical Storm Watch has been issued for Kauai County, including the islands of Kauai and Niihau. SUMMARY OF WATCHES AND WARNING IN EFFECT... A Tropical Storm Warning is in effect for... * Hawaii County * Maui County, including the islands of Maui, Lanai, Molokai and Kahoolawe A Hurricane Watch is in effect for... * Hawaii County * Maui County, including the islands of Maui, Lanai, Molokai and Kahoolawe * Oahu A Tropical Storm Watch is in effect for... * Kauai County, including the islands of Kauai and Niihau. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours. A Hurricane Watch means that hurricane conditions are possible within the watch area, in this case within the next 36 to 48 hours. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, in this case within the next 36 to 48 hours. Interests elsewhere in the main Hawaiian Islands, and in the Papahanaumokuakea Marine National Monument, should monitor the progress of this system. For storm information specific to your area, please monitor products issued by the National Weather Service office in Honolulu Hawaii. DISCUSSION AND OUTLOOK ---------------------- At 500 AM HST (1500 UTC), the center of Hurricane Douglas was located near latitude 19.1 North, longitude 148.4 West. Douglas is moving toward the west-northwest near 18 mph (30 km/h). This motion is expected to continue with a slight decrease in forward speed today, followed by a slight turn toward the west tonight through Monday. On the forecast track, Douglas will be near the main Hawaiian Islands late tonight through Sunday night. Maximum sustained winds are near 105 mph (165 km/h) with higher gusts. Gradual weakening is expected through the weekend. However, Douglas is still forecast to be near hurricane strength when it nears the islands. Hurricane-force winds extend outward up to 25 miles (35 km) from the center and tropical-storm-force winds extend outward up to 105 miles (165 km). The estimated minimum central pressure is 975 mb (28.80 inches). HAZARDS AFFECTING LAND ---------------------- WIND: Hurricane conditions are possible across portions of the main Hawaiian Islands late tonight through Sunday night. Tropical Storm conditions are expected across Hawaii County and Maui County beginning late tonight or Sunday. Tropical Storm conditions are possible across Kauai County late Sunday or Sunday night. SURF: Large swells generated by Douglas are expected to affect the Hawaiian Islands this weekend. These swells are likely to cause life-threatening surf and rip current conditions for the next couple of days. RAINFALL: Heavy rainfall associated with Douglas is expected to affect portions of the main Hawaiian Islands from late tonight through Monday. Total rain accumulations of 5 to 10 inches are possible from Maui County westward to Kauai County, with the greatest amounts in elevated terrain. This rain may result in life-threatening flash flooding and land slides, as well as rapid water level rises on small streams. Douglas is expected to produce 2 to 5 inches of rainfall over the northern half of the Big Island. Key messages for Douglas can be found in the Tropical Cyclone Discussion under AWIPS header HFOTCDCP2 and WMO header WTPA32 PHFO.

Updates on Hurricane Douglas can be found here.

Programming note

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