Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 251820
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
120 PM CDT WED MAR 25 2015

.UPDATE FOR 18Z AVIATION DISCUSSION

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 424 AM CDT WED MAR 25 2015

DRY SLOT MOVING IN ON THE SOUTHSIDE OF A STRONG SHORTWAVE MOVING
INTO NW MN HAS QUICKLY FORCED THE PRECIP OUT OF THE MPX AREA THIS
MORNING. THE REST OF THE DAY...THIS DRY SLOT LOOKS TO REMAIN IN
PLACE...WITH THE MAJORITY OF THE DEFORMATION PRECIP LOOKING TO STAY
CLOSER TO THE SFC LOW THAT WILL BE MOVING ACROSS THE ARROWHEAD.
STILL...HI-RES MODELS TO SHOW SOME PRECIP SNEAKING DOWN INTO OUR FAR
NRN COUNTIES...SO MAINTAINED SOME LOW CHANCE POPS ALONG OUR NRN
BORDER...THOUGH ANY ADDITIONAL AMOUNTS LOOK FAIRLY MINIMAL.

THAT SFC LOW IS QUITE THE COMPACT FEATURE...WITH A CENTRAL PRESSURE
DOWN TO ALMOST 1000 MB. AT 3 AM...ITS COLD FRONT WAS JUST ENTERING
WRN MN. A TONGUE OF 32-36 DEG DEWPOINTS OUT AHEAD OF THIS BOUNDARY
HAS RESULTED IN RATHER SOUPY CONDITIONS DEVELOPING WITH HAZE AND
CEILINGS UNDER 500 FT. HOWEVER...THIS BOUNDARY IS REALLY STARTING TO
PICK UP SOME STEAM...WITH IMPROVEMENTS TO VFR CONDITIONS ALREADY
COMING INTO WRN MN IN ITS WAKE. THE HRRR HAS HAD A GOOD HANDLE ON
THIS CLEARING MOVING EAST ACROSS THE DAKOTAS AND BASED ON THE
HRRR...WE SHOULD SEE THESE LOW CLOUDS CLEAR OUT PRETTY QUICK THIS
MORNING...WITH THE BACK EDGE OF THE CLOUDS REACHING I-35 AROUND 7 AM
AND CLEARING THE EAST END OF THE MPX CWA AROUND 10 AM. WE MAY SEE
SKIES BRIEFLY CLEAR OUT THIS MORNING...BUT THERE IS AN EXTENSIVE
STRATOCU DECK IN THE CYCLONIC CIRCULATION BACK ACROSS THE DAKOTAS
THAT IS QUICKLY FILLING IN THIS CLEARING. FOR THE SKY
GRIDS...FOLLOWED THE IDEA OF THE HRRR WITH BKN-OVC CONDITIONS
FILLING IN ACROSS THE ENTIRE AREA BY LATE MORNING. WITH THE CLOUD
COVER IN MIND...KEPT HIGHS FOR TODAY FAIRLY LOW...MIXING IN SOME GEM
TO FURTHER COOL OUR REMNANT SNOW COVER...WHICH WE HAVE HAD A PRETTY
GOOD WARM BIAS IN FOR OUR HIGHS THE PAST COUPLE OF DAYS.

BESIDE THE CLOUDS...WE WILL SEE SOME STRONG WEST WINDS DEVELOP BY
MID MORNING. WE WILL BE AN IDEAL SPOT FOR SEEING STRONG WINDS ON THE
SOUTHSIDE OF THE SFC LOW...WITH 3 MB/3 HR PRESSURE
RISES...SUBSIDENCE WITHIN THE DRY SLOT...AND DEEP MIXING ALL
CONSPIRING TO LEAD TO EXCELLENT DOWNWARD TRANSFER OF MOMENTUM.
GFS/NAM/HRRR/RAP BUFR SOUNDINGS SHOW TOP OF THE CHANNEL MIX WINDS
IN THE LOW 40S OUT AT AXN/MOX. EXPECT US TO HAVE NO PROBLEM GETTING
SUSTAINED WINDS AROUND 30 WITH GUSTS TO 40 TO 45 MPH FROM WEST
CENTRAL IN CENTRAL MN...SO HAVE ISSUED A WIND ADVY IN THOSE AREAS.

TONIGHT...WE WILL LOOSE THE GUSTINESS IN THE WINDS...BUT WITH
GRADIENT REMAINING STRONG...WE WILL BE ABLE TO MAINTAIN BREEZY NW
WINDS THROUGH THE NIGHT. WILL WILL SEE CLOUDS CLEAR OUT FOR THE MOST
PART AS WELL...WITH LOWS FALLING BACK INTO THE 20S AS OUR MOMENTARY
PAUSE IN SPRING CONTINUES.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 424 AM CDT WED MAR 25 2015

A CLASSIC SPRING FLOW PATTERN IS SETTING UP ACROSS THE U.S. CONUS
OVER THE NEXT 7-10 DAYS. THE LONG WAVE PATTERN IS HIGHLY
AMPLIFIED THROUGH THE EXTENDED...WHICH MEANS THE UPPER MISSISSIPPI
RIVER VALLEY WILL SEE A COUPLE DECENT TEMPERATURE SWINGS OVER THE
NEXT WEEK AS THE RIDGE/TROUGH PATTERN TRANSLATES EAST.

THERE ARE A COUPLE CHANCES FOR LIGHT PRECIP OVER THE NEXT SEVERAL
DAYS LOCALLY. THE FIRST IS A CHANCE FOR VERY LIGHT SNOW ACROSS
WESTERN MN FRIDAY NIGHT ALONG THE BACK SIDE OF THE EASTWARD
ADVANCING SURFACE HIGH. MID-LOW LEVEL WARM ADVECTION KICKS IN LATE
IN THE DAY ON FRIDAY. THE 25.00Z NAM AND ECMWF HAVE SOME LIGHT QPF
IN THE WESTERN FORECAST AREA. IT IS WORTH A SLIGHT CHANCE OF SNOW
MENTION IN THE FORECAST...BUT THAT IS ABOUT IT FOR NOW. THE GFS
NEVER SATURATES DOWN LOW AND THUS REMAINS DRY. THE NAM SEEMS A
LITTLE AGGRESSIVE WITH THE DEPTH OF MOISTURE AND RESULTING QPF.
OVERALL...THE BEST MOISTURE REMAINS JUST TO THE SOUTHWEST OF THE
FORECAST AREA. SO...WE WILL CONTINUE TO DOWNPLAY THIS FRIDAY
NIGHT EVENT...UNLESS SOMETHING CHANGES OVER THE NEXT COUPLE MODEL
CYCLES. THE SECOND PRECIP EVENT IS A LITTLE FARTHER DOWN THE ROAD
ON SATURDAY NIGHT INTO SUNDAY. THIS SYSTEM HAS SOME PUNCH UPSTAIRS
WITH 12HR 500MB HEIGHT FALLS BETWEEN 160-200M AND A NICE DEEP
SURFACE CYCLONE FORECASTED TO RIDE JUST NORTH OF THE MN/CANADIAN
BORDER...HOWEVER...THAT IS THE PROBLEM AT THIS POINT. IT IS TOO
FAR NORTH TO BE MUCH OF A CONCERN. A COLD FRONTAL TROUGH PASSES
THROUGH THE FORECAST AREA...BUT THESE FRONTS TYPICALLY DO NOT
PRODUCE A LOT OF PRECIP UNLESS THERE IS A REALLY GOOD SOUTHERLY
MOISTURE FETCH AND WE CAN TAP THE GULF. THAT IS NOT THE CASE AT
THIS POINT...WITH THE 925-850MB WINDS HAVING MORE OF A SOUTHWEST
COMPONENT. WE WOULD END UP WITH A LIGHT RAIN/SNOW MIX IF NOTHING
CHANGES DRAMATICALLY. PRECIP ASIDE...THAT WEEKEND SYSTEM LOOKS TO
BRING A LOT OF WIND WITH IT...FIRST OUT OF THE SOUTH...THEN
NORTHWEST BEHIND THE COLD FRONT.

IN TERMS OF TEMPERATURES...WE WILL RUN BELOW NORMAL THROUGH THE
WORK WEEK...WARM THROUGH THE WEEKEND...WITH A RETURN TO MILD
WEATHER EARLY NEXT WEEK AS THE RIDGE BUILDS IN FROM THE WEST. THE
OPERATIONAL/ENSEMBLE GFS AND ECMWF ALL GENERALLY HAVE THIS BIG
PICTURE TREND. WE RAISED TEMPS A BIT THROUGH THE EXTENDED. OUR
OFFICE TEMPERATURE VERIFICATION /AND MOST OF THE MODEL
VERIFICATION/ HAS SHOWN A PRONOUNCED COOL BIAS OVER THE PAST
COUPLE WEEKS...SO THAT IS SOMETHING WE WILL HAVE TO TAKE INTO
ACCOUNT AS WE MOVE FORWARD. WE DO HAVE SNOW ON THE GROUND IN
PLACES NOW...BUT THAT WILL DISAPPEAR IN A HURRY EVEN WITH THE
COOLER TEMPS BEING FORECAST.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1241 PM CDT WED MAR 25 2015

SURFACE LOW IS MOVING EAST THROUGH THE ARROWHEAD THIS
AFTERNOON...AND A LARGE STRATOCU DECK REMAINS ACROSS MN AND WI.
HOWEVER...STRONG SUBSIDENCE ACROSS THE EASTERN DAKOTAS IS
CURRENTLY BLOWING A HOLE IN THE CLOUD DECK AND THAT TREND IS
EXPECTED TO CONTINUE EASTWARD THIS AFTERNOON AND EVENING. BEFORE
THE CLOUDS SCATTER OUT...EXPECTING RADIATIONAL HEATING AND DEEP
MIXING TO HELP THE CLOUD BASE TO LIFT ABOVE 3K FT THIS AFTERNOON
ACROSS MOST OF THE AREA. VERY STRONG WEST WINDS HAVE BEEN REALIZED
TODAY AT THE SURFACE AND WILL CONTINUE THROUGH THE AFTERNOON
BEFORE SLOWLY DISSIPATING THROUGH THE EVENING...BUT WILL REMAIN
AROUND 10KTS OVERNIGHT. SKIES WILL BE MOSTLY CLEAR TONIGHT
THROUGH TOMORROW MORNING ACROSS THE AREA.

KMSP...WENT MORE OPTIMISTIC WITH THIS ISSUANCE WITH VFR EXPECTED
BY LATER THIS AFTERNOON. WIND FORECAST ON TRACK AND HIGH
CONFIDENCE REMAINS.

/OUTLOOK FOR KMSP/
FRI...VFR. WINDS LGT AND VRB.
SAT...MVFR POSSIBLE WITH CHC -RA/-SN LATE. WINDS S 10-15 KTS.
SUN...VFR. PRECIP DEPARTING EAST IN THE MORNING...SKIES CLEARING
IN THE AFTERNOON. WINDS TURNING NW 15-20G25KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY UNTIL 6 PM CDT THIS EVENING FOR MNZ041>043-047>050-
     054>058-064.

WI...NONE.
&&

$$

SHORT TERM...MPG
LONG TERM...CLF
AVIATION...SPD


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