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000
FXUS63 KMPX 160407
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1107 PM CDT SAT MAR 15 2014

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 323 PM CDT SAT MAR 15 2014

ANOTHER QUIET PERIOD IN THE SHORT TERM AS THE UPPER MISSISSIPPI
RIVER VALLEY FINDS ITSELF SANDWICHED BETWEEN TWO SYSTEMS. THE
FIRST IS A 1008MB SURFACE LOW THAT AS OF EARLY THIS AFTERNOON
WAS LOCATED ALONG THE NE/KS BORDER. THIS LOW WILL PROPAGATE
SOUTHEAST TODAY...WITH A BAND OF HEAVY SNOW EXPECTED TO DEVELOP
ACROSS CENTRAL IOWA. MEANWHILE A WEAK LEE SIDE LOW WILL DEVELOP IN
ALBERTA...AND THIS WILL CREATE SOUTHEASTERLY WINDS OVER THE HIGH
PLAINS. MN/WI WILL LIE IN BETWEEN THESE TWO SYSTEMS...AND AS A
RESULT THE WINDS WILL GO CALM AND LOW TEMPERATURES WILL DROP BELOW
ZERO ACROSS THE ST CROIX RIVER VALLEY AND POINTS EASTWARD.
TEMPERATURES WILL MODERATE SUNDAY AS SOUTHEASTERLY FLOW DEVELOPS
AHEAD OF THE AFOREMENTIONED LEE SIDE LOW. NO PRECIPITATION IS
EXPECTED.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 323 PM CDT SAT MAR 15 2014

ATTENTION WILL BE MOST FOCUSED ON THE INCOMING PROLONGED WINTER
STORM SYSTEM EXPECTED TO IMPACT THE WFO MPX CWFA MON NIGHT THRU
WED.

TO START...A WEAK CLIPPER-TYPE SYSTEM WILL DROP INTO THE REGION
FROM CENTRAL MANITOBA SUN NIGHT INTO MON. THIS COMPACT SYSTEM WILL
REMAIN MOSTLY IN CANADA...BUT A SWD EXTENDING TROF WILL SWEEP THRU
NRN AND CENTRAL MN...POSSIBLY BRINGING SOME -SN WITH IT FOR NRN
AND WRN PORTIONS OF THE CWFA. LITTLE TO NO SNOW ACCUM IS EXPECTED
WITH THIS SYSTEM.

HOWEVER...WHAT THIS WEAK SYSTEM WILL DO ON ITS BACKSIDE IS ALLOW
FOR SFC WINDS TO BECOME SLY AND UPR LVL FLOW TO BECOME MORE
ZONAL...EVEN SLIGHTLY SW. THESE SHIFTS WILL ALLOW NOTICEABLY
WARMER AIR TO INFILTRATE THE REGION NOT ONLY AT THE SFC BUT THRU
THE BLYR AHEAD OF THE MORE POTENT SYSTEM FOR THE FIRST HALF OF THE
WEEK. THIS WARMER AIR WILL BE FELT ON MON AS HIGHS IN WRN THRU
SRN MN HIT THE LWR 50S AND POSSIBLY EVEN NEAR 60 IN FAR SWRN MN.
THIS WARM AIR INTRUSION...WHERE IT SETS UP DEPENDING ON THE TRACK
OF THE SYSTEM...WILL BE A MAJOR PLAYER IN DETERMINING P-TYPE FOR
MUCH OF THE CWFA. PRECIP WILL MOVE INTO THE REGION MON
NIGHT...STARTING OUT AS LIQUID -RA FOR THE AREA. HOWEVER...AS THE
SYSTEM TREKS ACRS SRN/CENTRAL MN AND COLDER SFC AIR IS DRAGGED
DOWN FROM CANADA ON ITS BACKSIDE...THE WARMER AIR ALOFT WILL AID
IN TRANSITIONING THE PRECIP TO A MIXTURE OF -ZR AND
-IP...ESPECIALLY -ZR GOING INTO THE TUE MORNING RUSH HOURS
TIMEFRAME FOR MUCH OF CENTRAL MN...INCLUDING THE TWIN CITIES
METRO. STILL TOO EARLY TO DETERMINE HOW MUCH ICING WOULD BE
EXPECTED BUT WITH LIQUID QPF IN THE 0.10-0.15 AREA...IT WOULD NOT
BE UNREASONABLE FOR POTENTIALLY UP TO A TENTH OF AN INCH OF ICE TO
DEVELOP OVER CENTRAL/ERN MN. THERE WILL THEN BE ADDITIONAL CHANGES
IN P-TYPE ALL ACRS THE CWFA AS THE WARMER AIR EXPANDS NEAR THE SFC
IN SWRN PORTIONS OF THE CWFA WHILE THE COLDER AIR DEEPENS IN NWRN
PORTIONS...SO THERE WILL BE GRADIENTS DEVELOPING OF
-RA/-FZRA/-IP/-SN ACRS THE AREA DURG THE DAY ON TUE. THIS SYSTEM
GRADUALLY WRAPS UP WITHIN ITSELF AND ROTATES AWAY TUE NIGHT INTO
WED AS A DIGGING UPR LVL TROF PICKS UP THE SYSTEM...ENDING ANY
REMAINING WAA AND ALLOWING DEEPER COLD AIR ADVECTION TO MOVE INTO
THE REGION. THIS WOULD THEN FORCE ANY REMAINING ICY/LIQUID PRECIP
TO TRANSITION TO -SN...THUS THE BEST CHCS FOR ACCUMULATING SNOW
WOULD COME LATE TUE NIGHT THRU WED BEFORE THE SYSTEM EXITS. SNOW
AMOUNTS WILL AGAIN HAVE A SHARP GRADIENT AS 5-9 INCHES IS EXPECTED
OVER NRN MN WITH AMOUNTS DROPPING SIGNIFICANTLY GOING SWD.
SO...ATTM...IT LOOKS LIKE NRN PORTIONS OF THE MPX CWFA WOULD SEE
UP TO ARND 3 INCHES...AND NEARLY AN INCH IN THE TWIN CITIES METRO
AND EAU CLAIRE...WITH LITTLE-TO-NO ACCUMULATIONS NEAR THE IA
BORDER. BUT...AGAIN...THE CAVEAT THAT EVEN MINOR CHANGES IN THE
TRACK CAN HAVE SIGNIFICANT RAMIFICATIONS WITH SNOW AMOUNTS.

THIS SYSTEM WILL EXIT THE AREA BY LATE WED...ALLOWING FOR HIGH
PRES TO GLIDE ACRS THE REGION WED NIGHT INTO THU. HOWEVER...
FOLLOWING FOR THU NIGHT INTO FRI WILL BE ANOTHER WINTER STORM
SYSTEM THAT WILL BRING MORE MIXED PRECIPITATION TO THE REGION.

SO...OVERALL...CERTAINLY AN ACTIVE PATTERN THAT DESERVES MUCH
ATTENTION AND MAY WELL RESULT IN MULTIPLE CHANGES TO THE FORECAST.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1101 PM CDT SAT MAR 15 2014

NO BIG CHANGES TO THE PREVIOUSLY ISSUED 00Z TAF. NORTHERN AND
PORTIONS OF CENTRAL MN SHOULD GET A LITTLE LIGHT SNOW NEAR THE END
OF THE TAF PERIOD...SO THIS WAS MENTIONED AT KAXN...BUT NOT
INCLUDED AT OTHER TAF SITES. HIGH CONFIDENCE IN VFR CONDITIONS
OVER THE NEXT 24 HOURS OTHERWISE.

KMSP...

WE PUSHED BACK THE TIMING OF THE NE TO SE WIND SHIFT...BUT NO BIG
CHANGES TO THE TAF OTHERWISE. THE RADAR SCOPE COULD SHOW LIGHT SNOW
WELL NORTH OF THE AIRPORT SUNDAY NIGHT...BUT JUST EXPECT
INCREASING MID-HIGH CLOUDS AT KMSP. VFR IS EXPECTED. THE WEATHER
SHOULD TURN MORE ACTIVE LATE MONDAY THROUGH WEDNESDAY.

/OUTLOOK FOR KMSP/

MON...VFR WITH MVFR AND -RA POSSIBLE LATE. WINDS S AT 10G15KTS.
TUE...MVFR WITH IFR AND -SN/RA/FZRA POSSIBLE. WINDS NE AT
10G20KTS.
WED...MVFR WITH IFR AND SN POSSIBLE EARLY...THEN VFR.
WINDS NW AT 20G30KTS.

&&

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

$$

SHORT TERM...JRB
LONG TERM...JPC
AVIATION...CLF