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000
FXUS63 KMPX 230915
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
415 AM CDT THU MAY 23 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT THU MAY 23 2013

FOR THE FIRST TIME IN WHAT SEEMS LIKE QUITE SOME TIME WE CAN SEE
MOONLIGHT OUTSIDE OUR BACK DOOR THIS MORNING HERE AT THE NWS OFFICE
IN CHANHASSEN. THE SURFACE LOW THAT BROUGHT 6-7 CONSECUTIVE DAYS OF
MEASURABLE RAINFALL AND 4 TO 5 INCHES IN MANY LOCATIONS ACROSS THE
FORECAST AREA IS NOW OVER THE GREAT LAKES AND WE ARE GAINING ABOUT 1
MB PER HOUR AT THE SURFACE EARLY THIS MORNING. NORTHEAST FLOW AND
MUCH DRIER WEATHER IS EXPECTED TODAY AND TONIGHT. THE DRY AND BREEZY
NORTHEAST LOW LEVEL FLOW TODAY WILL MAKE IT FEEL EVEN COOLER THAN
THE ALREADY BELOW NORMAL TEMPERATURES IN THE FORECAST TODAY. WITH
LITTLE SENSIBLE WEATHER TO SPEAK OF IN THE SHORT TERM...ONE OF THE
BIGGER CHALLENGES TODAY IS TO DETERMINE JUST HOW DRY THE DEWPOINTS
AND HUMIDITY WILL GET THIS AFTERNOON. THE SATURATED GROUND WILL
CERTAIN AID IN PROVIDING EXTRA BOUNDARY LAYER MOISTURE.
NONETHELESS...MIXING DOWN THE AIR BETWEEN 900-800 MB GIVES US A VERY
DRY AFTERNOON. THE NAM FORECAST SOUNDINGS FOR TODAY SUGGESTS WE CAN
MIX AS HIGH AS 830 MB...WHILE THE RAP...SREF...AND GFS MIX TO 850
MB...870 MB...AND 875 MB RESPECTIVELY. THERE SHOULD BE VIRTUALLY
CLOUD FREE SKIES TODAY.

THE COOL AND DRY DAY TODAY WILL SET THE STAGE FOR A CHILLY NIGHT
TONIGHT. NO MAJOR CHANGE TO THE TEMPERATURE FORECAST WITH LOWER 40S
WEST AND LOW TO MID 30S EAST ACROSS THE FORECAST AREA FOR LOWS
TONIGHT. THE TWIN CITIES METRO SHOULD ALSO STAY IN THE LOWER 40S
TONIGHT. WE KEPT THE MENTION OF FROST IN FAR EASTERN MN AND WEST
CENTRAL WI. IN FACT...EXPECTED TEMPERATURES ARE COLD ENOUGH IN
PORTIONS OF WI TO WARRANT A FROST ADVISORY LATE TONIGHT.

.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 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1024 PM CDT WED MAY 22 2013

VFR SPREADING IN FAST...WITH ALL TAF SITES VFR AT 06Z. SOME MID
CLOUDS REMAIN DROPPING IN FROM THE NORTH DURING THE NIGHT AND THEN
CLEARING THROUGH 12Z. MAY SEE FEW CUMULUS DEVELOP OVER WEST NEAR
THE RIDGE AND FURTHER TO THE SOUTHEAST DURING THE DAY...SO DID
INCLUDE THAT. VFR NONETHELESS...WITH NORTHEAST WINDS BECOMING MORE
EAST TO SOUTHEAST INTO THURSDAY NIGHT. MAY SEE SOME GUSTS OVER
MAINLY THE EASTERN SITES DURING THE DAY. RIDGE BUILDS IN THURSDAY
NIGHT WITH LIGHT WINDS AND SOME HIGH CLOUDS MOVING INTO THE WEST
LATE.

KMSP...VFR CONDITIONS DURING THE PERIOD. SOME MID CLOUDS REMAINING
EARLY...THEN SOME CUMULUS POSSIBLE INTO THE DAY THURSDAY...DISSIPATING
BY EVENING. NORTHEAST TO EAST WINDS A BIT GUSTY INTO THE DAY...THEN
BECOMING LIGHT SOUTHEAST BY THURSDAY NIGHT.

/OUTLOOK FOR KMSP/
FRIDAY...VFR. SOUTHEAST WIND 5 TO 10 KT.
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>016-025-027-028.

&&

$$

SHORT TERM...CLF
LONG TERM...RAH
AVIATION...DWE