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000
FXUS63 KMPX 231906
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
ISSUED BY NATIONAL WEATHER SERVICE LA CROSSE WI
206 PM CDT THU MAY 23 2013

.SHORT TERM...THROUGH MONDAY
ISSUED AT 204 PM CDT THU MAY 23 2013

23.12Z RAOBS SHOW GOOD 925-850MB COLD ADVECTION ACROSS THE WRN GREAT
LAKES THIS MORNING IN MODERATE NORTHEAST FLOW. FRONTAL SLOPE OVER
THE STATE IS SOMETHING THAT WILL COME INTO PLAY FOR UPCOMING
FORECAST AND HOW FAR IT SLIDES SOUTHWEST. AT 12Z KINL-KABR HAD A 7C
TEMPERATURE DIFFERENCE AT 850MB /12C AT 925MB/. A MASSIVE DRYING
ACROSS MN OCCURRED OVERNIGHT WITH PRECIPITATELY WATER VALUES
PLUMMETING FROM 0.90 TO 0.32 INCHES...OR 136 TO 48 PERCENT NORMAL.
THE SURFACE RIDGE NOSING IN IS QUITE DRY WITH PRECIPITABLE WATER
VALUES IN THE 30 PERCENT RANGE ACROSS SRN CANADA. THIS GAVE WAY TO A
SUNNY BUT COOL DAY TODAY. A HIGHER AMPLITUDE RIDGE AXIS IS
ANCHORED IN THE DAKOTAS AND SOUTH...WHILE A DEEPER CYCLONE HAS NOW
SHIFTED ONSHORE INTO THE NWRN U.S. NUMEROUS SPOKES OF ENERGY ARE
CIRCULATING AROUND THAT LOW...ONE OF WHICH IS QUITE STRONG OVER
NEVADA WITH RAP ANALYSIS SHOWING A TROPOPAUSE FOLD TO NEAR
500MB...ON THE POLEWARD SIDE OF A MEASURED 100KT 250MB JET CORE
NOSE. THIS IS DRIVING HEIGHT FALLS ACROSS MT/ID/UT. SURFACE DEW
POINTS OF MEANING FOR CONVECTION ARE LOCATED IN OKLAHOMA...SOON TO
RETURN NORTHWARD.

FORECAST IS ON TRACK FOR CALMING WINDS TONIGHT AND CLEAR SKIES.
WIDESPREAD FROST SHOULD OCCUR WITH LOWER 30S FORECAST ACROSS NWRN
WI. WITH LOWER DEW POINTS OVER NWRN WI COUNTIES CURRENTLY...HAVE
DECIDED TO JUST ADD ALL OF THOSE COUNTIES INTO THE FROST ADVISORY.

BIG PICTURE DURING THIS PERIOD IS FALLING HEIGHTS AND PRESSURE IN
THE FRONT RANGE WITH SOUTHERLY FLOW INCREASING AND A RETURN OF
MOISTURE TO NEB/SD FRIDAY NIGHT. THIS WILL PLACE THE LOW-LEVEL
THERMAL BOUNDARY ACROSS THE FORECAST AREA FROM 850-925MB...SLIGHTLY
DISPLACED SWWRD...FROM KABR-KMLI. THE CONSENSUS NCEP MODELS AT
23.12Z REMAIN CONSISTENT WITH THEIR PREVIOUS RUNS ON THE FRONTAL
BOUNDARY BECOMING ACTIVE IN THE DAKOTAS/NEB FRIDAY EVENING AND
SHIFTING EAST INTO MN/IA OVERNIGHT. THE 23.00Z ECMWF/UKMET
SOLUTIONS DO AS WELL...HOWEVER THEY REMAIN FURTHER WEST.

THE 300/305K SURFACE IN THE NCEP SOLUTIONS REMAINS CONSISTENT WITH
AN 8G/KG MOISTURE SURGE ISENTROPICALLY LIFTING AND CONVERGING INTO
CENTRAL AND ERN MN FRIDAY OVERNIGHT WITH A FETCH OF ABOUT 500 J/KG
OF MUCAPE FEEDING IT. THE NAM SEEMS TO BE THE MOST AGRESSIVE. NOT
OVERLY IMPRESSIVE FOR SEVERE WEATHER...BUT RATHER THERE IS ENOUGH
FORCING TO GENERATE RA/TSRA SWWRD OF MSP. THE ECMWF SOLUTIONS
SUGGEST MORE OF A FOCUS IN SRN/SWRN MN. THE MAIN QUESTION IS HOW
FAR EAST DOES THIS CONVECTIVE COMPLEX TRACK FRIDAY NIGHT AND HOW FAR
EAST DOES THE FRONTAL BOUNDARY LIFT. HAVE INCREASED RAIN CHANCES
FURTHER EAST FOR FRIDAY NIGHT AND SATURDAY...HOWEVER WITH THE
VERIFICATION RECORD OF THE ECMWF...THERE IS STILL A CHANCE THE
EASTERN AREAS WILL BE DRY. CONFIDENCE IS LOW ON THE EXACT
LOCATION OF THE WEATHER...BUT HIGHER THAT IT WILL BE AN ACTIVE
FRONTAL ZONE WITH SHRA/ISO TSRA.

THIS QUESTION REMAINS THROUGH MONDAY...HOW FAR EAST WILL THE
FRONTAL BAND BE LOCATED. THE FRONT WILL LIKELY REMAIN ACTIVE WITH
SHOWERS/STORMS AND CLOUDS...AND HIGHS QUITE A BIT COOLER THANOUTSIDE
THE BAND. OVERALL...HAVE INCREASED RAIN CHANCES IN THE WRN/SRN
FORECAST AREA AND TRIED TO REMAIN NEARLY DRY IN THE EAST. SEEMS
LIKE IT WILL BE A CLOUDY WEEKEND...AND THUS HAVE LOWERED HIGHS
SUNDAY AND MONDAY AS WELL. SEVERE WEATHER THREATS ARE MOST
POSSIBLE IN SWRN MN CLOSER TO THE CAPE POOL...AND MONDAY LOOKS
MOST FAVORABLE SHOULD THE INSTABILITY INCREASE AS THE WARM FRONT
MOVES TOWARD MN. HOWEVER...ACTIVITY ALONG THAT FRONT THIS WEEKEND
MAY HAVE MUCH TO DO WITH HOW THE ENVIRONMENT/FRONT EVOLVES MONDAY.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 415 AM CDT THU MAY 23 2013

THE LONG TERM BEGINS WITH A LARGE HIGH PRESSURE SYSTEM OVER THE
WESTERN GREAT LAKES REGION. MUCH OF FRIDAY WILL BE DRY...WITH THE
EXCEPTION OF THE FAR WEST WHERE STRONG LOW LEVEL THETA-E ADVECTION
WILL COMMENCE IN THE AFTERNOON ON THE BACK SIDE OF THE HIGH. THIS
COUPLED WITH A SHORT WAVE AND MID LEVEL FRONTOGENESIS MOVING EAST
FROM THE NORTHERN PLAINS WILL DRIVE SHOWERS AND ISOLATED
THUNDERSTORMS INTO THE FAR WEST BY LATE AFTERNOON...WITH THE
ACTIVITY PASSING ACROSS THE FA FRIDAY NIGHT AND EARLY SATURDAY.
ELEVATED INSTABILITY IS MINIMAL FRIDAY NIGHT AND SEVERE WEATHER IS
NOT EXPECTED. THE BEST LOW LEVEL MOISTURE TRANSPORT IS AIMED FROM
THE CENTRAL PLAINS INTO IA FRIDAY NIGHT WITH JUST ABOUT ALL MODEL
SOLUTIONS POINTING TO THE HIGHEST QPF STAYING SOUTH OF MN.

IN THE WAKE OF THE SHORT WAVE ON SATURDAY...WE ARE BEGINNING TO SEE
THE NAM AND SREF TAKING ON MORE OF WHAT THE ECMWF HAS BEEN SHOWING
FOR 3 DAYS NOW...AND THAT IS A MORE AMPLIFIED FLOW ALOFT. THIS IS
VERY EVIDENT LOOKING AT THREE RUNS OF THE ECMWF SPACED 24 HOURS
APART. DEEPER UPPER LOWS ALONG BOTH COAST WITH MORE RIDGING IN THE
CENTER OF THE COUNTRY. WITH TIME...THIS BUILDS THE SURFACE HIGH
PRESSURE SYSTEM OVER THE GREAT LAKES BACK WEST ACROSS THE FA ALONG
WITH DRIER AIR. USING THE ECMWF OUTRIGHT WOULD PLACE DRY WEATHER
OVER ALL BUT OUR FAR WESTERN AND SOUTHERN COUNTIES IN MN FOR
SUNDAY AND MONDAY. GOING AGAINST THE GRAIN HOWEVER ARE THE GFS AND
GEM. BOTH ARE ADAMANT ON DRIVING WAVE AFTER WAVE ALOFT THROUGH THE
REGION BOTH DAYS WITH CONVECTIVE CLUSTERS. MODEL RUN QPF IS IN THE
SEVERAL INCH RANGE ACROSS PARTS OF THE MN CWA. ON THE OTHER HAND...
THE ECMWF ONLY HAS A TENTH TO A HALF INCH FROM NORTHEAST TO
SOUTHWEST ACROSS OUR AREA RESPECTIVELY FROM FRIDAY THROUGH
MONDAY. HENCE...THE WEEKEND/HOLIDAY MAY TURN OUT BETTER THAN THE
FORECAST INDICATES IF THE ECMWF IS MORE CORRECT. POPS ARE MORE
ALIGNED NOW WITH VERY LOW CHANCES IN WI WITH HIGHER CHANCES NEAR THE
WESTERN AND SOUTHERN BORDER.

ALTHOUGH THE RAIN CHANCES ARE DIMINISHING AFTER SATURDAY
MORNING...THERE IS GOOD CONSENSUS THAT ABUNDANT LOW LEVEL MOISTURE
WILL COVER THE AREA WITH A WARM FRONT REMAINING SOUTH OF US. THIS
WILL LIKELY YIELD PLENTY OF CLOUD COVER WITH HIGH TEMPERATURES
REMAINING IN THE 60S SATURDAY AND SUNDAY WITH UPPER 60S TO LOWER
70S ON SUNDAY. SHOWERS AND THUNDERSTORMS SHOULD BECOME MORE COMMON
OVER THE REGION FROM TUESDAY ONWARD AS THE TROUGH IN THE WEST
MOVES EAST. THIS WILL LIFT THE LOW PRESSURE SYSTEM AND WARM FRONT
INTO OUT AREA. THIS WILL ALSO INCREASE OUR THREAT FOR SEVERE
WEATHER.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1243 PM CDT THU MAY 23 2013

HIGH PRESSURE AREA BUILDING IN WITH NEARLY CLEAR SKIES/VFR.
LARGEST 3 HOURLY PRESSURE CLIMBS ARE SHIFTING OFF TO THE SOUTHEAST
SO GRADIENT WILL SLACKEN CONSIDERABLY GOING INTO THIS EVENING.
EXPECT ANY LINGERING GUSTS TO CALM DOWN AND WITH RIDGE AXIS
SPREADING THROUGH TONIGHT...GRADUAL SHIFT TO SOUTHEAST LOW LEVEL
FLOW WILL MATERIALIZE GOING INTO FRIDAY MORNING. DRY AIRMASS SHOULD
KEEP SKIES CLEAR THROUGH MOST OF FRIDAY AS WELL.

KMSP...

VFR CONDITIONS TO CONTINUE. NORTHEAST WIND THIS AFTERNOON WILL
DECREASE AND SLOWLY BECOME SOUTHEAST BY FRIDAY MORNING.

/OUTLOOK FOR KMSP/

FRIDAY NIGHT...VFR. CHANCE OF SHOWERS. SOUTHEAST WIND 5 TO 15 KT.
SATURDAY...BRIEF MVFR CEILINGS POSSIBLE WITH A CHANCE OF
SHRA/TSRA. SOUTHEAST WIND 10 TO 20 KT.
SATURDAY NIGHT...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A
CHANCE OF SHRA/TSRA. SOUTHEAST WIND 10 TO 20 KT.
SUNDAY...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A CHANCE OF
SHRA/TSRA...BRIEF IFR CONDITIONS POSSIBLE. SOUTHEAST WIND 10 TO 20
KT.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM CDT FRIDAY FOR
     WIZ014>016-023>028.

&&

$$

SHORT TERM...BAUMGARDT/ARX
LONG TERM...RAH
AVIATION....SHEA/ARX