Nowcast: Locally heavy downpours

A quasi-stationary frontal boundary has set up right in the eastern half of the Twin Cities today. It appears this front will be the focus for scattered showers and thunderstorms through the evening.

Update 5:12pm:

Possible wall cloud near 494 and Hwy 169 on MNDOT traffic cam.

Update 5pm:

Hevay downpours in eastern Eden Prairie and west Bloomington prompt an urban flood advisory from NWS.

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FLOOD ADVISORY

NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN

459 PM CDT WED JUL 7 2010

MNC053-080100-

/O.NEW.KMPX.FA.Y.0019.100707T2159Z-100708T0100Z/

/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

HENNEPIN MN-

459 PM CDT WED JUL 7 2010

THE NATIONAL WEATHER SERVICE IN THE TWIN CITIES HAS ISSUED AN

* URBAN AND SMALL STREAM FLOOD ADVISORY FOR AREAS IN...

SOUTHEASTERN HENNEPIN COUNTY IN EAST CENTRAL MINNESOTA...

* UNTIL 800 PM CDT

* AT 455 PM CDT...TRAINED WEATHER SPOTTERS REPORTED THUNDERSTORMS

WITH HEAVY RAINFALL ACROSS THE ADVISORY AREA. A STORM SPOTTER

IN WESTERN BLOOMINGTON REPORTED RAIN FALLING AT A RATE OF AROUND 2

INCHES IN AN HOUR.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE SOME FLOODING TO

OCCUR...ESPECIALLY IN AREAS OF POOR DRAINAGE. SOME LOCATIONS THAT

MAY EXPERIENCE FLOODING INCLUDE...BLOOMINGTON...EDEN

PRAIRIE...EDINA AND RICHFIELD. THIS INCLUDES THE INTERSTATE 35

CONSTRUCTION AREA FROM BLOOMINGTON THROUGH RICHFIELD.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE MINOR FLOODING OF SMALL

CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES

AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS.

&&

Update 4:30pm:

Twin Cities NWS issues NOWCAST on storms.

SHORT TERM FORECAST

NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN

426 PM CDT WED JUL 7 2010

MNZ076>078-083>085-092-093-072330-

BLUE EARTH-FARIBAULT-FREEBORN-GOODHUE-LE SUEUR-RICE-STEELE-WASECA-

INCLUDING THE CITIES OF...ALBERT LEA...MANKATO...OWATONNA...RED WING

426 PM CDT WED JUL 7 2010

.NOW...

HEAVY RAIN PRODUCING THUNDERSTORMS WILL CONTINUE TO ADVANCE

ACROSS SOUTH CENTRAL MINNESOTA LATE THIS AFTERNOON. SOME OF

THE STRONGER STORMS MAY DUMP AN INCH TO AN INCH AND A HALF OF

RAIN IN LESS THAN A HOUR. THIS MAY CAUSE SOME PONDING OF WATER

IN AREAS OF POOR DRAINAGE. AT 420 PM THE LEADING EDGE OF THE

STRONGER STORMS EXTENDED FROM NEAR NORTHFIELD TO OWATONNA TO THE

WELLS AND KIESTER AREA. BEFORE 530 PM THEY SHOULD REACH

ZUMBROTA...BLOOMING PRAIRIE AND ALBERT LEA.

$$

MNZ053-060>063-069-070-072330-

ANOKA-CHISAGO-DAKOTA-HENNEPIN-RAMSEY-SCOTT-WASHINGTON-

INCLUDING THE CITIES OF...MINNEAPOLIS...ST PAUL...STILLWATER

426 PM CDT WED JUL 7 2010

.NOW...

STRONG THUNDERSTORMS WILL AFFECT THE EASTERN TWIN CITIES METRO AREA

UNTIL AROUND 6 PM THIS EVENING. AT 420 PM THE STRONGER

STORMS WERE NEAR LINO LAKES...STILLWATER...COTTAGE GROVE...AND

HAMPTON. IN ADDITION TO VERY HEAVY RAIN SOME SMALL HAIL AND GUSTY

WINDS ARE ALSO POSSIBLE. SOME STREET FLOODING IS POSSIBLE AS AN INCH

OR MORE OF RAIN IS POSSIBLE IN LESS THAN AN HOUR. THESE STORMS WILL

GENERALLY MOVE TO THE NORTHEAST AT 15 TO 20 MPH.

$$

WIZ014>016-023>028-072330-

BARRON-CHIPPEWA-DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST CROIX-

INCLUDING THE CITIES OF...CHIPPEWA FALLS...EAU CLAIRE...LADYSMITH...

RICE LAKE

426 PM CDT WED JUL 7 2010

.NOW...

SCATTERED THUNDERSTORMS WILL AFFECT WEST CENTRAL WISCONSIN THROUGH

THE EARLY EVENING HOURS. AT 420 PM SOME OF THE STRONGER STORMS WERE

NEAR LADYSMITH TO BLOOMER TO EAU CLAIRE. OTHER STRONG STORMS WERE

BEGINNING TO CROSS THE ST. CROIX RIVER TOWARD NEW RICHMOND...

OSCEOLA...AND RIVER FALLS. SMALL HAIL AND VERY HEAVY RAIN IS

POSSIBLE FROM THE STRONGER STORMS. THEY WILL MOVE TOWARD THE

NORTHEAST AT 15 TO 20 MPH.

$$

BAP

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Radar Update 3:47pm: Heavier rain cells continue to favor central and east metro for now. There is some sign that storms may "back build" into the central and western metro over the next two hours.

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2:52pm radar update: Heavy downpours between downtown Minneapolis and St. Paul and the SE metro.

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Twin Cities radar loop shows storms favoring the southest metro Wednesday afternoon.

It appears the heaviest rain corridor may favor the south and east half of the metro, as well as the I-35 corridor southward to Iowa. Since the storms are slow moving, the tropical downpours may result in some hefty rain totals over an inch in some areas.

As is often the case with summer convective thunderstorms, rainfall amounts will be highly localized. The western metro and areas to the west may see only widely scattered activity tonight, as a second cool front pushes in from the west. Still, a few thunderstomrs may pop up west of the frontal boundary.

It appears most of the storms will stay below severe limits, but some may produce locally heavy rains that may cause local street flooding this evening. Keep an eye on storms approaching from the southwest, especially in the eastern metro this evening.

-Latest Twin Cities radar loop

PH