Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 230009
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
709 PM CDT WED OCT 22 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 343 PM CDT WED OCT 22 2014

FAIRLY STOUT SE WINDS OUT THERE TODAY IN RESPONSE TO THE TIGHT
PRESSURE GRADIENT BETWEEN A 1028MB HIGH OVER THE GREAT LAKES AND A
1002 MB LOW OVER CENTRAL MANITOBA. AT 3 PM...A SFC TROUGH EXTENDED
FROM NEAR DEVILS LAKE SOUTH TO MITCHEL AND DOWN TO THE CENTRAL
NEB/KS BORDER. JUST WEST OF THIS SFC FEATURE THERE IS A NEGATIVELY
TILTED SHORT WAVE THAT HAS A NICE PUSH OF DRY AIR ON WATER VAPOR
MOVING ACROSS THE WRN DAKOTAS. IT IS THIS UPPER WAVE THAT WILL BE
THE PRIMARY DRIVER OF A LINE OF SHOWERS THAT WILL MOVE ACROSS THE
AREA TONIGHT. PREVIOUS FORECAST HAD A PRETTY GOOD HANDLE ON THIS
PRECIP BAND...WITH THE MAIN CHANGE TODAY BEING TO SHRINK THE WIDTH
OF THE BAND OF CATEGORICAL POPS MOVING ACROSS THE AREA. THIS MEANT
SLOWING DOWN THE ARRIVAL OF THE PRECIP BY A COUPLE OF
HOURS...WHILE SPEEDING UP FURTHER ITS DEPARTURE FROM WEST TO EAST
THRU THU MORNING. DID REMOVE THE THUNDER MENTION AS WELL AS BEST
LI/S ARE PEGGED TO BE BARELY BELOW ZERO...WITH SPC SREF CALIBRATED
THUNDERSTORM PROBS LOOKING MEAGER AS WELL. A FEW FOLKS WILL
UNDOUBTEDLY HEAR A RUMBLE OF THUNDER OR TWO...BUT WOULD RATHER NOT
SPREAD THUNDER WORDING ACROSS A LARGE CHUNK OF THE AREA TO COVER A
FEW FLASHES OF LIGHTNING. LESS CONVECTION ALSO MEANS LOWER
RAINFALL RATES...SO DID CUT BACK ON QPF AMOUNTS SOME...WITH
AMOUNTS ACROSS THE AREA NOW GENERALLY A TENTH TO A THIRD OF AN
INCH.

WE WILL SEE PRETTY AGGRESSIVE CLEARING BEHIND THE RAIN BAND
TONIGHT...SO WE WILL HAVE TO KEEP ON EYE ON THE POTENTIAL FOR FOG TO
DEVELOP. WINDS WILL GO LIGHT...BUT NOT COMPLETELY CALM...SO THIS MAY
HELP LIMIT THE FOG DEVELOPMENT. AT THE MOMENT...THE GREATEST
POTENTIAL FOR FOG LOOKS TO EXIST FROM MANKATO UP THROUGH ST. CLOUD
GIVEN EXPECTED TIMING OF THE CLEARING AND THE PLACEMENT OF THE SFC
TROUGH LATE TONIGHT. AFTER THAT...A BEAUTIFUL THURSDAY WILL UNFOLD
AS STRONG SUBSIDENCE IN THE WAKE OF TONIGHTS SHORTWAVE WILL HELP
CLEAR THE SKIES OUT. WILL SEE WRLY WINDS DEVELOP BEHIND TONIGHTS SFC
TROUGH AS WELL...WITH A NICE CHINOOK WIND EXPECTED ACROSS THE NRN
PLAINS. FAVORED HIGHS THURSDAY TOWARD THE BIAS CORRECTED
GUIDANCE...WITH HIGHS RANGING FROM THE MID 70S OUT AROUND
MADISON...WITH TEMPERATURES ABOUT 20 DEGREES COOLER OVER TOWARD
LADYSMITH...WHERE MORE CLOUD COVER INTO THE EARLY AFTERNOON WILL
HELP KEEP TEMPERATURES COOLER.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 343 PM CDT WED OCT 22 2014

TWO SIGNIFICANT CHGS IN THE EXTENDED PERIOD. FIRST...DUE TO THE
SLOWER MODEL SOLUTION OF THE NORTHEASTERN STORM SYSTEM OVER THE NEXT
FEW DAYS...SLIGHTLY COOLER TEMPS SUNDAY ARE MORE LIKELY VS. THE
EXPECTED 70 DEGREE HIGH PREVIOUSLY FORECAST. THUS...DUE TO THE
SLOWER SOLUTION...A STORM SYSTEM MOVING ACROSS THE GREAT LAKES
SATURDAY WILL HOLD BACK THE COLDER AIR ACROSS THE UPPER MIDWEST. IN
ADDITION...MORNING LOWS SUNDAY AROUND 40 WILL HOLD DOWN AFTN TEMPS
AS CLDS BEGIN TO INCREASE FROM THE S/SW. THE SECOND CHG IS RELATED
TO THE PHASING OF THE SOUTHERN/NORTHERN JETS WHICH LEADS TO
PRECIPITATION CHC/S ACROSS THE UPPER MIDWEST AS A STORM SYSTEM MOVES
OUT OF THE ROCKIES EARLY NEXT WEEK.

ONE OF THE MAIN WX INFLUENCES OVER THE NEXT WEEK IS THE CONSISTENT
FAST/PROGRESSIVE PATTERN. THE MOST ACTIVE WX WILL REMAIN ACROSS THE
NORTHEAST AND PACIFIC NW/NORTHERN ROCKIES. IN BETWEEN...PROBLEMS
EXIST DUE TO THE PHASING OF THE UPPER JETS. WILL REMAIN OPTIMISTIC
WITH A MORE UNSETTLED PATTERN NEXT WEEK. IN ADDITION TO THE
UNSETTLED PATTERN...TEMPS WILL LIKELY DROP TO NEAR NORMAL AS THE
MAIN UPPER JET CORE AND THICKNESS VALUES LOWER ACROSS THE NORTHERN
U.S. LATEST GFS STILL HAS A POTENT WX SYSTEM MOVING ACROSS THE UPPER
MIDWEST AROUND HALLOWEEN. THICKNESS VALUES AND ASSOCIATED WET-BULB
MEAN LAYER /1KM/ TEMPS ARE NEAR 0 TO +2C...LEADING TO SOME
PRECIPITATION TYPE PROBLEMS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 708 PM CDT WED OCT 22 2014

A BAND OF SHOWERS ACROSS FAR WESTERN MN WILL PROGRESS SLOWLY
EASTWARD OVERNIGHT...PASSING THROUGH THE TWIN CITIES BETWEEN
06Z AND 10Z. THE BACK EDGE OF THE SHOWERS SHOULD BE EAST OF KEAU BY
14Z. THERE WILL BE A PERIOD OF MVFR CEILINGS AND VISIBILITIES WITH
THE SHOWERS. THE LONGEST DURATION FOR THE MVFR CONDITIONS WILL BE
ACROSS FAR EASTERN MN AND WESTERN WI DUE TO THE PRECIPITATION
OCCURRING DURING THE LATE NIGHT/EARLY MORNING HOURS. THERE MAY BE
SOME EXTENSIVE FOG DEVELOP AS WELL LATE TONIGHT ON THE BACK EDGE
OF THE CLOUDINESS. THIS COULD IMPACT KSTC MORE THAN WHAT THE TAF
CURRENTLY INDICATES. MUCH OF THIS WILL DEPEND ON THE AMOUNT OF RAIN
THAT FALLS AND HOW QUICKLY CLEARING OCCURS. GUSTY SE WINDS WILL
DIMINISH EARLY THIS EVENING AND BECOME MORE SOUTHERLY DURING THE
NIGHT. WINDS BECOMING WSW ON THURSDAY.

KMSP...SHOWERS MOVING IN AFTER MIDNIGHT WITH MVFR CEILINGS AND
VISIBILITIES. THE MVFR CEILINGS WILL LIKELY PERSIST INTO THE MID
MORNING HOURS WITH CLEARING THEREAFTER.

/OUTLOOK FOR KMSP/

FRI...VFR. WINDS SSW AT 5-10KTS.
SAT...VFR. WINDS NW AT 10-15KTS.
SUN...CHC MVFR/-SHRA OVERNIGHT. WINDS SE AT 10-15KTS.

&&

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

$$

SHORT TERM...MPG
LONG TERM...JLT
AVIATION...RAH







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