A hot and steamy Memorial Day; excessive heat warning and air quality alert

Our heat wave continues today.

Highs in the 90s are expected over about the southern half of Minnesota, with 80s north. Areas near Lake Superior will be a bit cooler.

Twin Cities metro area temps will peak in the upper 90s, and a few spots in the metro could hit 100.

The heat index, which factors in the heat and the relative humidity, will top 100 degrees at times this afternoon:

NWS Twin Cities

There’s a heat advisory from 1 p.m. to 7 p.m. today for most of the southern half of Minnesota, plus parts of western Wisconsin.  The Twin Cities metro area is in a heat advisory until 1 p.m., then it becomes an excessive heat warning from 1 p.m. to 7 p.m.

Details of the metro area excessive heat warning:

URGENT – WEATHER MESSAGE
National Weather Service Twin Cities/Chanhassen MN
350 AM CDT Mon May 28 2018

MNZ060>063-068>070-281700-
/O.UPG.KMPX.EH.A.0001.180528T1800Z-180529T0000Z/
/O.NEW.KMPX.EH.W.0001.180528T1800Z-180529T0000Z/
/O.CON.KMPX.HT.Y.0001.000000T0000Z-180528T1800Z/
Hennepin-Anoka-Ramsey-Washington-Carver-Scott-Dakota-
Including the cities of Minneapolis, Blaine, St Paul, Stillwater,
Chaska, Shakopee, and Hastings
350 AM CDT Mon May 28 2018

…HEAT ADVISORY REMAINS IN EFFECT UNTIL 1 PM CDT THIS
AFTERNOON…
…EXCESSIVE HEAT WARNING IN EFFECT FROM 1 PM THIS AFTERNOON TO
7 PM CDT THIS EVENING…

The National Weather Service in Twin Cities/Chanhassen has issued
an Excessive Heat Warning, which is in effect from 1 PM this
afternoon to 7 PM CDT this evening. The Excessive Heat Watch is
no longer in effect.

* TEMPERATURE…Low temperatures in the 70s provided little relief
from the heat overnight, and will be followed by forecast highs
today in the upper 90s. Increasing humidity will result in peak
heat indices of 100 to 105 degrees during the afternoon.

* IMPACTS…Heat illnesses are possible for those active
outdoors or those susceptible to heat illnesses, such as
children and the elderly.

PRECAUTIONARY/PREPAREDNESS ACTIONS…

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 light weight and loose fitting clothing when
possible and drink plenty of water.

An Excessive Heat Warning means that a prolonged period of
dangerously hot temperatures will occur. The combination of hot
temperatures and high humidity will combine to create a dangerous
situation in which heat illnesses are likely. Drink plenty of
fluids…stay in an air-conditioned room…stay out of the sun…
and check up on relatives and neighbors.

Here are some heat safety tips, from the National Oceanic and Atmospheric Administration:

NOAA

These are the symptoms of heat stroke and heat exhaustion:

NOAA

Today will be our fifth consecutive day with a high temp of 90 degrees or higher in the Twin Cities metro area.

We’ve never seen more than four consecutive days of 90 or higher during May in the Twin Cities.

Our record high temp of 98 degrees for May 28 could be tied or broken today.

Updated weather information can be heard on the Minnesota Public Radio Network, and updates are also posted on the MPR News live weather blog.

Warm summer on tap?

This feels like summer, but summer doesn’t officially arrive until June.  May heat is often followed by a high number of 90 degree days in summer, according to the Minnesota State Climatology Office:

90-degree readings in the Twin Cities during May have occurred in 48 out of 146 years on record, or about 33% of the time. Only 23 years, however, or about 16%, have had more than one 90-degree day during May. Of those years, May of 1934 was by far the most extreme, with eight daily highs of at least 90 degrees, including a reading of 106 on May 31st.

We find that years with multiple 90-degree days during May have tended to be followed by summers that also have relatively high numbers of 90-degree days. The Twin Cities airport averages about 13 90-degree days per year, and 26% of years historically have had 20 or more such days. For years with at least two 90-degree days during May, however, the average number of 90-degree days for the year jumps to 23.4 (an 80% increase), and 74% of those years go on to have at least 20 90-degree days.

Air quality alert this afternoon and evening

The Minnesota Pollution Control Agency (MPCA) has issued an air quality alert for the Twin Cities metro area and much of southern Minnesota for this afternoon and early this evening:

MPCA/NWS

The air quality alert extends as far north as Stearns county over to Chisago county.

Rain opportunities

Scattered thunderstorms are possible in parts of northeastern Minnesota into late morning, then we’ll see a rain-free stretch for most of the state until late afternoon.

Scattered showers and thunderstorms are possible anywhere in Minnesota late this afternoon and this evening.

Many spots in Minnesota will see some periods of showers and thunderstorms Tuesday and Wednesday.

Alberto update

The center of subtropical storm Alberto moved closer to the U.S. coastline this morning:

NOAA Monday morning visible satellite loop, via College of DuPage

Here’s the morning update on Alberto, from the National Hurricane Center:

BULLETIN
Subtropical Storm Alberto Intermediate Advisory Number 13A
NWS National Hurricane Center Miami FL AL012018
700 AM CDT Mon May 28 2018

…ALBERTO MOVING SLOWLY NORTHWARD TOWARD THE COAST OF THE
FLORIDA PANHANDLE…

SUMMARY OF 700 AM CDT…1200 UTC…INFORMATION
———————————————-
LOCATION…29.0N 86.0W
ABOUT 100 MI…165 KM SSE OF DESTIN FLORIDA
MAXIMUM SUSTAINED WINDS…65 MPH…100 KM/H
PRESENT MOVEMENT…N OR 360 DEGREES AT 6 MPH…9 KM/H
MINIMUM CENTRAL PRESSURE…991 MB…29.26 INCHES

WATCHES AND WARNINGS
——————–
CHANGES WITH THIS ADVISORY:

None

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Watch is in effect for…
* Suwannee River to Navarre Florida

A Tropical Storm Warning is in effect for…
* Suwannee River to the Mississippi/Alabama border

A Storm Surge Watch means there is a possibility of life-
threatening inundation, from rising water moving inland from the
coastline, in the indicated locations. For a depiction of areas at
risk, please see the National Weather Service Storm Surge
Watch/Warning Graphic, available at hurricanes.gov.

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area.

For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.

DISCUSSION AND OUTLOOK
———————-
At 700 AM CDT (1200 UTC), the center of Subtropical Storm Alberto
was located near latitude 29.0 North, longitude 86.0 West. Alberto
is moving northward near 6 mph (9 km/h). A faster northward or
north-northwestward motion is expected during the next few days. On
the forecast track, the center of Alberto will cross the northern
Gulf Coast in the warning area this afternoon or evening. After
landfall, the system is forecast to move well inland into the
Tennessee Valley on Tuesday and into the Ohio Valley and Great Lakes
region on Wednesday and Thursday.

Maximum sustained winds are near 65 mph (100 km/h) with higher
gusts. Little change in strength is expected before Alberto reaches
the northern Gulf Coast later today. Steady weakening is forecast
after landfall, and Alberto will likely become a subtropical
depression tonight or early Tuesday and degenerate into a remnant
low by Tuesday afternoon.

Winds of 40 mph extend outward up to 105 miles (165 km) from the
center. An elevated observing station located about 15 miles (25
km) south of Apalachicola, Florida, has recently reported sustained
winds of 46 mph (74 km/h). A wind gust to 39 mph (63 km/h) was
recently observed at Apalachicola, Florida.

The estimated minimum central pressure from reconnaissance aircraft
data is 991 mb (29.26 inches).

HAZARDS AFFECTING LAND
———————-
RAINFALL: Alberto is expected to produce the following rain
accumulations through Tuesday:

Central Cuba…Additional 5 to 10 inches, isolated storm-totals of
20 to 25 inches.

The Florida panhandle into much of Alabama and western Georgia…4
to 8 inches, isolated 12 inches.

The Florida Keys and Florida peninsula…Additional 1 to 4 inches,
isolated 10 inches.

Rest of the Southeast and Tennessee Valley into the lower mid
Atlantic from Tennessee east through the Carolinas…2 to 6 inches.

Rains in Cuba could produce life-threatening flash floods and
mudslides. Flooding and flash flooding are possible in the
southeast United States, including Florida.

WIND: Tropical storm conditions will spread across the warning area
throughout the day.

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 if the peak surge occurs at the time of high tide…

Suwannee River to Navarre Florida…2 to 4 ft

The deepest water will occur along the immediate coast. Surge-
related flooding depends on the relative timing of the surge
and the tidal cycle, and can vary greatly over short distances. For
information specific to your area, please see products issued by
your local National Weather Service forecast office.

TORNADOES: A couple of brief tornadoes are possible today from
northern Florida into central and southern Georgia, southern South
Carolina, and southeastern Alabama.

SURF: Swells generated by Alberto will continue to affect the
eastern and northern Gulf Coast through Tuesday. These swells are
likely to cause life-threatening surf and rip current conditions.
For more information, consult products from your local weather
office.

Here’s Alberto’s projected path:

National Hurricane Center

Several areas will see heavy rainfall amounts:

NOAA Additional rainfall estimate through Wednesday night