Special Weather Statement, NWS Twin Cities, MN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
540 PM CDT MON JUL 23 2012

.UPDATED FOR 00Z AVIATION DISCUSSION BELOW...

.DISCUSSION...
THE UPPER LEVEL RIDGE ANCHORED OVER THE CENTRAL PLAINS WHICH HAS
BEEN RESPONSIBLE FOR KEEPING THE PRECIP CONFINED ACROSS SOUTHERN
CANADA WILL CONTINUALLY BE TRIMMED OFF ALONG ITS NORTHERN EDGE BY A
SERIES OF SHORTWAVES. THESE WAVES WILL INDUCE LOW LEVEL WARM AND
MOIST SOUTHERLY FLOW. THIS THETA_E ADVECTION WILL PROVIDE ADDED
SUPPORT FOR A FOCUSED AREA OF OVERNIGHT CONVECTION FROM EXTENDING
FROM CENTRAL MINNESOTA THROUGH WESTERN WISCONSIN. LOOKING AHEAD...A
POWERFUL SHORTWAVE CURRENTLY LOCATED OVER THE IDAHO PANHANDLE WILL
TRACK TOWARDS THE GREAT LAKES REGION AND DRIVE A COLD FRONT
THROUGH THE UPPERMIDWEST...SETTING THE STAGE FOR SOME MUCH COOLER
WEATHER.

TODAY THROUGH TUESDAY...WEST TO EAST ORIENTED FRONT IS NOTED ON
AFTERNOON SURFACE ANALYSIS FROM NEAR REDWOOD FALLS TO THE TWIN
CITIES TO EAU CLAIRE...WHILE VISIBLE/RADAR IMAGERY ILLUSTRATE AN
EXTENSIVE DECK OF HIGH CLOUDS AND ISOLD HIGH BASED SHOWERS SOUTH OF
THE BOUNDARY. IT IS A STICKY AFTERNOON...ESPECIALLY SOUTH OF THE
BOUNDARY WHERE DEWPOINTS ARE IN THE UPPER 60S TO MID 70S RANGE...AND
T/TD SPREADS ARE AROUND OR UNDER 10 DEGREES WITH LITTLE TO NO
BREEZE. HUMID CONDITIONS WILL REMAIN IN PLACE TONIGHT AS CLOUDS AND
PRECIPITATION CHANCES INCREASE WITH THE ASSISTANCE OF THE LLJ AND
ATTENDANT H85-H6 MOISTURE TRANSPORT. HAVE MAINTAINED THE HIGHEST
POPS /LIKELY/ BETWEEN 05Z AND 12Z TUESDAY. EXPECT RESIDUAL SHOWER
AND THUNDERSTORM ACTIVITY OVER EAST CENTRAL MN AND WEST CENTRAL WI
ON TUESDAY MORNING. WHILE SHOWER ACTIVITY SHOULD WANE FOR TUESDAY
AFTERNOON...A FAIR AMOUNT OF HIGH CLOUDS SHOULD KEEP TEMPS IN THE
MID TO UPPER 80S. HOWEVER...SOUTH CENTRAL/WEST MN COULD SNEAK INTO
THE LOWER 90S UNDER A BIT MORE SUNSHINE. - LS

TUESDAY NIGHT THROUGH SUNDAY...ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS WILL DEVELOP NEAR THE I-94 CORRIDOR TUESDAY NIGHT AS A
SURGE OF H925-H850 THETA_E ADVECTION LIFTS THROUGH THE UPPER
MISSISSIPPI RIVER VALLEY WITH THE STRENGTHENING LOW LEVEL JET. A
DPROG/DT OF SREF PRECIP SHOWS A NORTHWARD TREND..SO HAVE TRIED TO
TRIM BACK POPS ACROSS THE SOUTH. A FEW ELEVATED SEVERE STORMS ARE
POSSIBLE OVERNIGHT. THE CONDITIONAL THREAT FOR SEVERE WEATHER WILL
LAST THROUGH WEDNESDAY AS WELL. NUMERICAL MODELS SEEM TO LATCH ONTO
ANOTHER SHORTWAVE ORIGINATING FROM THE ROCKIES AND MOVING ACROSS THE
REGION WEDNESDAY AFTERNOON. THIS COMBINED WITH RIGHT ENTRANCE REGION
OF AN UPPER LEVEL JET WILL CREATE FAVORABLE DYNAMICS FOR A FEW
SEVERE THUNDERSTORMS BY LATE AFTERNOON. THE EXACT PLACEMENT FOR THE
HIGHEST SEVERE THREAT WILL DEPEND HEAVILY ON THE CLOUD COVER AND
LOCATION OF OUTFLOW BOUNDARIES FROM PRIOR CONVECTION. A COLD FRONT
SHOULD THE PUSH THROUGH THE REGION FOR THURSDAY AS THE
AFOREMENTIONED IDAHO PANHANDLE SHORTWAVE MOVES TOWARDS THE GREAT
LAKES. TRAILING IN IS WAKE ARE H850 TEMPS AROUND 12C...AND SURFACE
DEWPOINTS NEAR 60. THIS WILL RESULT IN MUCH MORE COMFORTABLE
CONDITIONS OVER MN/WI...WITH HIGHS NEAR OR SLIGHTLY BELOW THE
SEASONAL AVERAGE BY THE END OF THE WEEK. LOOKING AHEAD...AN UPPER
LEVEL RIDGE WILL BUILD ACROSS THE HIGH PLAINS...WITH SOUTHERLY FLOW
AND WAA RETURNING ACROSS THE WEST BY EARLY NEXT WEEK. A FEW
SHORTWAVES WILL TRAVERSE THE CREST OF THE RIDGE...AND AS A RESULT
HAVE A FEW 20/30 POPS LATER IN THE WEEKEND. - JRB

&&

.AVIATION.../00Z TAF ISSUANCE/
SCATTERED SHOWERS/SPRINKLES AROUND EARLY EVENING SHOULD ORGANIZE
FURTHER...LATER TONIGHT AS LOW LEVEL JET IMPINGES ON FRONT NEAR THE
SOUTH DAKOTA/IOWA/MINNESOTA BORDER.  SHOULD SEE ELEVATED THUNDER
LIFT INTO THE AREA WITH PREVIOUS TIMING LOOKING FAIRLY GOOD.  LITTLE
CHANGES NEEDED TO EARLIER PACKAGE OVERALL.  NORTHERLY WIND WILL
BECOME MORE EAST LATER TONIGHT AHEAD OF FRONT AND MORE SOUTHEAST
INTO TUESDAY AFTERNOON. DONT ANTICIPATE FRONT BECOMING ACTIVE AGAIN
UNTIL LATE TUESDAY AFTERNOON/EVENING.

KMSP...ISOLATED SHOWERS EARLY...BUT THE BULK OF THE ACTIVITY IS
EXPECTED TO ARRIVE AFTER 06Z VCNTY OF THE AIRFIELD.  THE THUNDER
THREAT IS MOST PROBABLE BETWEEN 06Z AND 12Z AS THE LOW LEVEL JET
INCREASES INTO THE REGION. NORTHERLY WINDS WILL SHIFT TO MORE EAST
LATER TONIGHT...AND THEN GRADUALLY VEER TO MORE SOUTHEAST DURING THE
DAY TUESDAY.

/OUTLOOK/
WEDNESDAY...VFR/MVFR WITH SHRA/TSRA POSSIBLE EARLY. WINDS VARIABLE AT
5 KTS.
THURSDAY...VFR WITH TSRA POSSIBLE. WINDS W/SW AT 5-10KTS.
FRIDAY...VFR. WINDS NW 5-10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

JRB/DE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1116 AM CDT MON JUL 23 2012

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
241630-
DOUGLAS-TODD-MORRISON-MILLE LACS-KANABEC-STEVENS-POPE-STEARNS-
BENTON-SHERBURNE-ISANTI-CHISAGO-LAC QUI PARLE-SWIFT-CHIPPEWA-
KANDIYOHI-MEEKER-WRIGHT-HENNEPIN-ANOKA-RAMSEY-WASHINGTON-
YELLOW MEDICINE-RENVILLE-MCLEOD-SIBLEY-CARVER-SCOTT-DAKOTA-
REDWOOD-BROWN-NICOLLET-LE SUEUR-RICE-GOODHUE-WATONWAN-BLUE EARTH-
WASECA-STEELE-MARTIN-FARIBAULT-FREEBORN-POLK-BARRON-RUSK-
ST. CROIX-PIERCE-DUNN-PEPIN-EAU CLAIRE-
1116 AM CDT MON JUL 23 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND
SOUTHERN MINNESOTA...AND WEST CENTRAL WISCONSIN.

.DAY ONE...THIS AFTERNOON AND TONIGHT

ISOLATED THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON FROM SOUTH
CENTRAL INTO WEST CENTRAL MINNESOTA. IF ANY ACTIVITY DOES OCCUR
THIS AFTERNOON...IT WILL HAVE THE RISK OF PRODUCING LARGE HAIL IN
EXCESS OF A QUARTER IN SIZE AND STRONG DAMAGING WINDS IN EXCESS
OF 60 MPH.

TONIGHT...THUNDERSTORMS ARE EXPECTED TO EXPAND RAPIDLY IN
COVERAGE...MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER. THESE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE VERY HEAVY DOWNPOURS...
ALONG WITH A SMALL THREAT FOR HAIL AND STRONG STRAIGHT LINE
WINDS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE THREAT FOR THUNDERSTORMS WILL CONTINUE THROUGH FRIDAY
AFTERNOON OF THIS WEEK. THE BEST CHANCES FOR THUNDERSTORMS LOOK
TO BE TUESDAY NIGHT INTO WEDNESDAY AS A COLD FRONT WORKS THROUGH
THE AREA AND AGAIN THURSDAY AFTERNOON AS A STRONG UPPER LEVEL
SYSTEM MOVES ACROSS THE REGION. AFTER A BRIEF BREAK FROM THE
ACTIVE WEATHER FRIDAY NIGHT AND SATURDAY...THUNDERSTORM CHANCES
WILL RETURN SATURDAY NIGHT INTO SUNDAY. THE BEST CHANCE FOR SEVERE
WEATHER WITH ALL OF THIS ACTIVITY WILL COME WITH THE PASSAGE OF
THE COLD FRONT WEDNESDAY AFTERNOON.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1101 PM CDT MON JUL 23 2012

MNZ069-070-077-078-240430-
DAKOTA-GOODHUE-RICE-SCOTT-
1101 PM CDT MON JUL 23 2012

AT 1059 PM CDT...WEATHER SERVICE RADAR WAS TRACKING A STRONG
THUNDERSTORM NEAR NEW MARKET. THIS STORM WAS MOVING EAST AT 35 MPH.

HAIL UP TO NICKEL SIZE AND HEAVY DOWNPOURS ARE EXPECTED WITH THIS
STORM.

* LOCATIONS IN OR NEAR THE PATH OF THIS STORM INCLUDE...
  NEW MARKET.
  ELKO.
  CASTLE ROCK.
  NORTHFIELD.
  RANDOLPH.
  STANTON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

&&

LAT...LON 4457 9282 4435 9291 4451 9351 4468 9343
TIME...MOT...LOC 0401Z 287DEG 30KT 4457 9335

JRB