Special Weather Statement, NWS Twin Cities, MN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
408 AM CDT MON JUN 13 2011

.DISCUSSION...

AN UNSETTLED WEATHER PATTERN ACROSS THE MIDWEST WILL PREVAIL
THROUGH THE FIRST HALF OF THIS WEEK...WITH SIGNS THAT IT MAY BE
THE RULE OF THUMB FOR THE NEXT 7 TO 10 DAYS. SO CHALLENGES OF
TIMING PRECIPITATION AND BEST THUNDER CHANCES WERE FOCUSED ON IN
THIS FORECAST CYCLE.

SYNOPSIS...A STRONG SHORT WAVE IS MOVING NORTHEAST FROM ND EARLY
THIS MORNING WHICH IS PRIMARILY RESPONSIBLE FOR THE GRADUALLY
DECAYING SHOWERS AND STORMS MOVING INTO WESTERN MN. AN OVERALL
CONVOLUTED FLOW PATTERN ACROSS THE WESTERN HALF OF THE U.S. HAS
MANY RIPPLES/SHORT WAVES WITHIN A GENERAL LONG WAVE TROUGH. IT
APPEARS ONE OF THESE MAY BE HELPING TO REBUILD CONVECTION ALREADY
IN NORTHERN NEBRASKA. ENERGY EVOLVING NEAR THE FOUR CORNERS WILL
EJECT EASTWARD LATER THIS AFTERNOON INTO TONIGHT TOWARDS SOUTHWEST
MN. THE SURFACE GRADIENT WILL INCREASE TODAY WITH GENERAL PRESSURE
FALLS ACROSS MUCH OF THE REGION. THE PRIMARY SURFACE LOW AND WARM
FRONT THOUGH WILL DEVELOP ACROSS KS AND NORTHERN MO IN THE NEXT 36
HOURS...AND WILL BE A FOCUS FOR HEAVIER PRECIPITATION LATE TONIGHT
INTO TUESDAY. SOME RESPITE IN FORCING IS SEEN WHILE THIS OCCURS
ON TUESDAY ACROSS THE IMMEDIATE AREA BEFORE THE PRIMARY POTENTIAL
VORTICITY ANOMALY MOVES ACROSS LATE TUESDAY NIGHT THROUGH
WEDNESDAY...BRINGING A RE-INCREASE IN SHOWER CHANCES.

NUMERICAL MODEL PREFERENCE...NO MODEL IS HANDING THE CURRENT
SHOWER ACTIVITY IN FAR WESTERN MN WELL...POSSIBLY STRUGGLING WITH
THE COLD POOL ORGANIZATION. SO HAVE GONE WITH FORCING FROM SHORT
TERM GUIDANCE A FEW HOURS LATER IN THE SOLUTIONS THAT MATCHES
BEST WITH ONGOING RADAR TRENDS. THE 13.00Z NAM AND GFS ARE FAIRLY
SIMILAR THROUGH THE NEAR 36 HOURS...WITH THE NAM A BIT MORE
EASTERLY ON ITS RAINFALL TONIGHT. HAVE PREFERRED A BLEND OF THESE
TWO MODELS.

THIS MORNING...UPPER LEVEL DIFFLUENCE AND CONTINUING 35-45 KT LOW-
LEVEL JET AS SEEN ON VAD PROFILERS CONTINUES TO SUPPORT THE RAIN
AREA IN WESTERN MN. THE LLJ IS FORECAST TO WEAKEN...ESPECIALLY
AFTER 9AM...AND SHOULD ALLOW FOR AT LEAST THUNDER TO BECOME WIDELY
ISOLATED. AREAL COVERAGE OF SHOWERS SHOULD DIMINISH GREATLY BY
LATE MORNING. RAIN FROM THIS ACTIVITY IS UNLIKELY TO REACH THE
TWIN CITIES.

THIS AFTERNOON INTO TONIGHT...CONTINUE WEAK ISENTROPIC ASCENT
WITHIN HIGHER PWAT AIR ACROSS WESTERN MN MAY SUPPORT REGENERATION
OF SHOWERS AND ISOLATED STORMS INTO THE AFTERNOON. A MUCH BETTER
CHANCE FOR SOUTHWEST MN WILL ARRIVE WITH THE SHORT WAVE ENERGY
FROM THE SOUTHWEST U.S. THIS MORNING. DIFFERENTIAL THETA-E
ADVECTION INCREASES ACROSS WESTERN IA AND SOUTHWEST MN THIS
EVENING IN RESPONSE TO THE LOW LEVEL JET INCREASING AHEAD OF THIS
FEATURE. THE NOSE OF THE MOISTURE TRANSPORT AND ASCENT ON THE
305-310K ISENTROPIC SURFACES DO NOSE INTO THAT AREA AS WELL.
ELEVATED LAPSE RATES MAY SUPPORT A SEVERE STORM OR TWO WITH
HAIL...BUT OVERALL THE DEEP LAYER SHEAR IS MARGINAL /25-35 KTS/.
THICKNESS DIFFLUENCE WOULD SUPPORT THE STORMS TO EVOLVE SOUTHEAST
CLOSER TO THE DEVELOPING LOW-LEVEL THERMAL GRADIENT NEAR THE IA/MO
BORDER. ACTIVITY IN THAT AREA LOOKS TO POTENTIALLY ROB OUR
MOISTURE ADVECTION AS THE NIGHT PROGRESSES. SO WHILE SHOWERS
SHOULD WORK EAST OVERNIGHT WITH THE SHORT WAVE ENERGY...THEY MAY
BE DECAYING AS THEY APPROACH/MOVE OVER THE TWIN CITIES LATE
TONIGHT. SO SOUTHERN MN LOOKS THE MOST FAVORED AREA FOR RAIN...WITH
QPF AMOUNTS OF 0.25 TO 0.50 OF AN INCH MOST FAVORED. 12.21Z SREF
INDICATED HIGHER PROBABILITIES OF GREATER QPF...BUT AT THIS POINT
IT SEEMED TO HAVE A NORTH BIAS WITH THAT HIGH QPF.

TUESDAY...AGAIN WITH AN EMPHASIS IN ACTIVITY TO THE SOUTH THERE
MAY BE LIMITED AMOUNT OF RAIN OVER THE IMMEDIATE REGION...ESPECIALLY
WITH NO STRONG SIGNAL OF A SHORT WAVE DURING TUESDAY AND EVEN SOME
ANTICYCLONIC FLOW INFRINGING FROM THE EAST WITH LOWER THETA-E
VALUES IN 1000-700MB LAYER RE-ADVECTING IN. PLENTY OF CLOUDS
SHOULD REMAIN...ESPECIALLY IN WESTERN MN. SO OVERALL TEMPERATURES
WILL BE VERY SIMILAR TO TODAY...WITH HIGHS OF UPPER 60S TO MID
70S.

TUESDAY NIGHT INTO WEDNESDAY...AS THE SHARP PV ANOMALY MOVES INTO
THE AREA FROM THE NORTHWEST...MODEL TIME HEIGHTS SATURATE AND SHOW
LAPSE RATE SUPPORT FOR SHOWERS AND ISOLATED THUNDERSTORMS UNDER
THE MID-LEVEL COLD POOL. THIS WILL ESPECIALLY BE TRUE DURING THE
DAY WEDNESDAY IT WOULD SEEM. HAVE LIKELY POPS ACROSS A LARGE PART
OF CENTRAL AND EASTERN MN AND WESTERN WI. HAVE INCHED HIGHS DOWN
ON WEDNESDAY IN THE EAST...WHICH MIGHT BE SEVERAL DEGREES BELOW 70
AGAIN.

BEYOND...HAVE MADE ONLY SLIGHT CHANGES WITH NUDGES TOWARDS THE
13.00Z EC. OTHERWISE NO CHANGES MADE. THE PATTERN IS FORECAST BY
MOST LONG RANGE MODELS TO REMAIN DISTURBED...BUT MILD...WITH
POTENTIAL SEVERE STORM CHANCES AT TIMES DURING THE JUNE 17TH-20TH
WINDOW.

&&

.AVIATION.../06Z TAF ISSUANCE/

CURRENTLY MAINLY CLR ACRS AREA. CURRENT CONVECTION ACRS THE CNTL
DKTS SHUD HV SUFFICIENT SUPPORT TO PUSH INTO WC MN LT TNGHT...MAINLY
AFFECTING AXN AFT ABT 10Z AS SHRTWV LIFTS NE ACRS NODAK.  BY 16Z
ENUF WND TO MIX DOWN SO XPCT GUST 20-25 KTS AT ALL TAF SITES.
MAIN FOCUS FOR NEXT ROUND OF SHWRS/TSTMS SHUD BE MON EVE/NITE ACRS
IA WITH LLJ ON THE INCRS AND FVBL UPPER DIVERGENCE.

KMSP...VFR CONDITIONS THROUGH THE PERIOD. SOME RISK OF SHWRS MON
EVE/NIGHT...BUT BEST FOCUS TO REMAIN ACRS IA.

&&

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

&&

MTF/BAP

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
428 AM CDT MON JUN 13 2011

MNZ041>045-047>052-054>070-073>078-082>085-091>093-141100-
DOUGLAS-TODD-MORRISON-MILLE LACS-KANABEC-STEVENS-POPE-STEARNS-
BENTON-SHERBURNE-ISANTI-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-
428 AM CDT MON JUN 13 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
MINNESOTA...EAST CENTRAL MINNESOTA...SOUTH CENTRAL MINNESOTA...
SOUTHEAST MINNESOTA...SOUTHWEST MINNESOTA AND WEST CENTRAL
MINNESOTA.

.DAY ONE...TODAY AND TONIGHT

THERE IS A CHANCE OF THUNDERSTORMS ACROSS WESTERN MINNESOTA TODAY
AND ACROSS MOST OF THE REMAINDER OF CENTRAL AND SOUTHERN MINNESOTA
TONIGHT. A FEW SEVERE THUNDERSTORMS ARE POSSIBLE LATE THIS
AFTERNOON INTO TONIGHT ACROSS FAR WEST CENTRAL INTO SOUTH CENTRAL
MINNESOTA...MAINLY SOUTH OF THE MINNESOTA RIVER. THE PRIMARY
THREATS FROM ANY SEVERE STORMS WOULD BE LARGE HAIL.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THERE IS A CHANCE OF THUNDERSTORMS ACROSS THE OUTLOOK AREA FROM
TUESDAY THROUGH WEDNESDAY...THEN AGAIN FRIDAY INTO NEXT WEEKEND.
AT THIS TIME...THE LATTER PERIOD LOOKS TO SUPPORT A BETTER CHANCE
FOR POSSIBLE SEVERE STORMS.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT.

MNZ053-WIZ014>016-023>028-141100-
CHISAGO-POLK-BARRON-RUSK-ST. CROIX-PIERCE-DUNN-PEPIN-CHIPPEWA-
EAU CLAIRE-
428 AM CDT MON JUN 13 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF FAR EAST
CENTRAL MINNESOTA...NORTHWEST WISCONSIN AND WEST CENTRAL
WISCONSIN.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THERE IS A CHANCE OF THUNDERSTORMS ACROSS THE OUTLOOK AREA FROM
TUESDAY THROUGH WEDNESDAY...THEN AGAIN FRIDAY INTO NEXT WEEKEND.
AT THIS TIME...THE LATTER PERIOD LOOKS TO SUPPORT A BETTER CHANCE
FOR POSSIBLE SEVERE STORMS.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
604 AM CDT MON JUN 13 2011

MNZ041-047-048-054>056-064-065-131215-
CHIPPEWA-DOUGLAS-LAC QUI PARLE-POPE-RENVILLE-STEVENS-SWIFT-YELLOW
MEDICINE-
604 AM CDT MON JUN 13 2011

...GUSTY WINDS OVER CHIPPEWA...DOUGLAS...LAC QUI
PARLE...POPE...RENVILLE...STEVENS...SWIFT AND YELLOW MEDICINE
COUNTIES THROUGH 715 AM CDT...

AT 600 AM CDT...WEATHER SERVICE RADAR WAS TRACKING SHOWERS AND
THUNDERSTORMS WITH GUSTY WINDS IN THEIR WAKE. THE GUSTY WINDS
EXISTED ALONG A LINE EXTENDING FROM 15 MILES SOUTHWEST OF WHEATON TO
6 MILES SOUTH OF CANBY. THIS AREA WAS DEVELOPING NORTHEAST WITH THE
SHOWERS AND THUNDERSTORMS. WINDS OF UP TO 50 MPH HAVE ALREADY BEEN
OBSERVED IN NORTHEAST SOUTH DAKOTA TO NEAR THE STATE LINE SINCE 540
AM.

WINDS UP TO 50 MPH ARE EXPECTED WITH THESE STORMS ACROSS FAR WEST
CENTRAL MINNESOTA.

* LOCATIONS IN OR NEAR THE PATH OF THESE STORMS INCLUDE...
  PORTER.
  MADISON.
  DAWSON.
  CANBY.
  PROVIDENCE.
  CERRO GORDO.
  APPLETON.
  BENSON.
  MORRIS.
  MONTEVIDEO.
  GRANITE FALLS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THE GUSTY WINDS MAY BE CAPABLE OF KNOCKING DOWN SMALL TREES...TREE
LIMBS...AND POWERLINES. SEEK SAFE SHELTER UNTIL THE STORM HAS PASSED.

&&

LAT...LON 4527 9646 4528 9643 4526 9632 4520 9612
      4540 9614 4541 9625 4575 9627 4576 9577
      4610 9576 4611 9548 4479 9527 4462 9619
      4462 9645
TIME...MOT...LOC 1100Z 247DEG 31KT 4569 9670 4463 9626