000
FXUS63 KMPX 071827
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1227 PM CST SAT DEC 7 2013

.UPDATE...
ISSUED AT 1225 PM CST SAT DEC 7 2013

VERY LITTLE HAS CHANGED WITH 12Z GUIDANCE COMING IN THIS
MORNING...WITH 3 TO 5 INCHES OF SNOW STILL EXPECTED ROUGHLY
SOUTHEAST OF A NEW ULM...TO THE TWIN CITIES...TO SIREN WI LINE. AS A
RESULT...HAVE DECIDED TO CUT TO THE CHASE AND GET A WINTER WEATHER
ADVISORY OUT NOW FOR THE SNOW ON SUNDAY. ONLY MEANINGFUL CHANGE
WITH THE 12Z MODELS IS THAT THEY ALL HAVE COME DOWN SOME ON TOTAL
QPF...WITH EVERYTHING NOW INDICATING QPF REMAINING UNDER A QUARTER
INCH...LIMITING THE POTENTIAL FOR SEEING ANY 6 INCH OR GREATER
TOTALS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM CST SAT DEC 7 2013

VERY COLD TEMPS THIS MORNING WITH MANY READINGS BETWEEN 10 AND 20
BELOW ZERO AS OF 230 AM. THE COLDEST AREAS WERE LOCATED IN MORRISON
COUNTY WHERE DEEPER SNOW EXISTS AND WINDS ARE LESS. EVEN WITH A
5 TO 10 MPH WIND...WIND CHILL VALUES HAVE AVERAGED BETWEEN 20 AND 35
BELOW ZERO...WITH THE COLDEST READINGS IN WEST CENTRAL/CENTRAL MN.
REGIONAL SATELLITE IMAGERY IS SHOWING MANY CLEAR SKIES OVERHEAD WITH
THE NEXT STORM SYSTEM EXPECTED TO PRODUCE MORE SNOWFALL BY LATE
TONIGHT...AFFECTING THE GREAT BASIN OF NEVADA/UTAH. THRU THIS
EVENING...NO WX PROBLEMS WILL OCCUR WITH THE EXCEPTION OF COLD WIND
CHILLS. WILL CONTINUE WITH THE WIND CHILL WARNING/ADVISORY THRU NOON
DUE TO THE VERY COLD TEMPS AND WINDS STILL AVERAGING CLOSE TO 10 MPH
THRU THE MORNING. LATE TONIGHT...AND WITH THE COMBINATION OF RAPID
RETURN OF MID LEVEL MOISTURE AND THE INFLUX OF UPPER LEVEL ENERGY
ASSOCIATED WITH THE SHRTWV ACROSS THE GREAT BASIN...SHOULD INDUCE A
BROAD AREA OF LIGHT SNOW ACROSS THE PLAINS OF NEBRASKA/IOWA/SD. AS
WITH ANY ARCTIC AIR MASS...IT WILL TAKE SOME TIME TO SATURATE THE
LOWER LEVELS OF THE ATMOSPHERE WHICH MAY DELAY THE ONSET OF -SN BY
SUNDAY MORNING. HOWEVER...SHORT TERM MODELS ARE SHOWING A STRONG
UPGLIDE OF ADIABATIC OMEGA OR ISENTROPIC LIFT ACROSS SOUTHERN MN
STARTING 6Z-12Z/8. EVEN SOME OF THE LOCAL MODELS REFLECTIVITY OUTPUT
IS SHOWING A BROAD AREA OF -SN SPREADING ACROSS FAR SW MN AFT
6Z...AND ACROSS MOST OF SOUTHERN MN BY 12Z. WILL CONTINUE THE SAME
FORECAST WITH THE BULK OF THE QPF AND -SN ACROSS SW/SC MN DURING THE
OVERNIGHT HRS. THE INTENSIFY AND COVERAGE SHOULD EXPAND ON SUNDAY AS
THE SYSTEM MOVES FURTHER TO THE E/NE.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 407 AM CST SAT DEC 7 2013

THINGS ARE RIGHT ON TRACK FOR THE NEXT BOUT OF MEASURABLE SNOWFALL
TO ARRIVE ON SUNDAY...AS THE SURFACE HIGH SHIFTS EAST AND A
MIDLEVEL TROUGH LIFTS NORTHEAST FROM THE FOUR CORNERS REGION TO
LAKE MICHIGAN. EXPECT SNOW TO BEGIN BY DAYBREAK SUNDAY...AS MODEST
/BUT DEEP/ ISENTROPIC LIFT EXPANDS NORTH AND EAST ACROSS THE AREA.
QPF AMOUNTS REMAIN ON THE MODEST SIDE...BUT SNOW RATIOS
/APPROXIMATELY 20-25 TO 1/ SHOULD HELP PLOWABLE SNOWFALL AMOUNTS
TO COME TO FRUITION. EXPECT THIS TO BE ESPECIALLY TRUE FROM SOUTH
CENTRAL MN NORTHEAST TO EAST CENTRAL MN AND WEST CENTRAL
WI...WHERE A SOLID SWATH OF 3-5 INCHES IS EXPECTED BETWEEN 09Z
SUNDAY AND 09Z MONDAY. GIVEN THE LONG DURATION OF A LIGHT/FLUFFY
SNOW EVENT /WITHOUT INTENSE BURSTS OF HEAVIER SNOW/...AND THE
ABSENCE OF STOUT WINDS...THE NEED FOR AN ADVISORY APPEARS SOMEWHAT
BORDERLINE AT THIS POINT. WE WILL SEE WINDS PICK UP ON MONDAY
HOWEVER...WHICH WILL LIKELY YIELD BLOWING AND DRIFTING SNOW...AND
ANOTHER BRUSH WITH WIND CHILL ADVISORY CRITERIA ACROSS WEST
CENTRAL MN. HIGHS ON MONDAY WILL STRUGGLE TO RISE ABOVE ZERO
DEGREES ACROSS WEST CENTRAL MN...WITH SINGLE DIGITS EXPECTED AREA-
WIDE.

ON MONDAY NIGHT INTO TUESDAY...A NORTHERN STREAM WAVE IS SLATED TO
DIVE SOUTHEAST ACROSS THE AREA FROM CANADA...AND BRING A QUICK
SHOT OF LIGHT SNOW TO CENTRAL MN AND NORTHERN WI. AS TYPICAL OF
CLIPPER SYSTEMS...SNOW ACCUMULATIONS AROUND ONE INCH WOULD BE
COMMON WITH THIS FEATURE. A REINFORCEMENT OF THE COLD AIR
INFILTRATES THE AREA IN THE WAKE OF CLIPPER...WITH 5 BELOW TO 15
BELOW LOWS ON WEDNESDAY MORNING...AND YET ANOTHER POTENTIAL FOR 25
BELOW TO 30 BELOW WIND CHILLS.

THERE ARE INDICATIONS THAT SOME RELIEF FROM THE BITTER COLD WILL
ARRIVE LATE NEXT WEEK...AS LOW/MID LEVEL HEIGHTS RISE SLIGHTLY. BY
FRIDAY...HIGHS IN 20S APPEAR POSSIBLE ACROSS MUCH OF THE AREA.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1225 PM CST SAT DEC 7 2013

NOT MUCH IN THE WAY OF CHANGES WERE MADE TO TAFS AS 12Z GUIDANCE
HAS COME IN FAIRLY SIMILAR TO PREVIOUS GUIDANCE IN TERMS OF
SNOWFALL EXPECTED TO SPREAD INTO THE AREA LATE TONIGHT AND PERSIST
THROUGH THE DAY ON SUNDAY. ONCE SNOW MOVES IN...VIS SHOULD DROP
DOWN QUICKLY INTO THE 1-3SM RANGE AND STAY THERE THROUGH THE
DURATION OF THE EVENT. GIVEN DRY NATURE OF THE AIRMASS...CIGS
SHOULD REMAIN WITHIN MVFR...WITH ANY IFR CIGS THE RESULT OF VV
ISSUES. TIMING IN TAFS IS MORE IN LINE WITH THE NAM...WITH THE
GFSLAMP INDICATING A TIMING 2 TO 4 HOURS SLOWER THAN CURRENT
TAFS...BUT WITH MODELS TENDING TO NOT BRING WAA TYPE SNOWS IN FAST
ENOUGH...PREFER THE SLIGHTLY FASTER TIMING. ALL TERMINALS WILL SEE
SNOW...WITH 1-2 INCHES FOR AXN/STC/RWF AND MORE 3 TO 5 INCHES FOR
MSP/RNH/EAU...WITH EAU THE MOST LIKELY TO HIT THE HIGH END OF THAT
SCALE. WILL BE A DRY AND BLOWABLE SNOW...BUT WINDS STRONG ENOUGH
TO BLOW THINGS AROUND DO NOT LOOK TO ARRIVE UNTIL MONDAY MORNING.

KMSP...MODEL AGREEMENT AND RUN-TO-RUN CONSISTENCY REMAINS GOOD
WITH UPCOMING SNOW...SO FOR A TAF WITH SNOW IN IT...CONFIDENCE IS
FAIRLY HIGH. ONCE THE SNOW ARRIVES...IT LOOKS TO BE FAIRLY
CONSISTENT...WITH 1-3 SM VSBY EXPECTED PERSIST FROM ABOUT 12Z
SUNDAY MORNING THROUGH 3Z SUNDAY EVENING. RATES WILL NEVER BE ALL
THAT EXCESSIVE...LIKELY MAXING OUT AT A THIRD OF AN INCH PER HOUR.
WILL BE A DRY FLUFFY SNOW...WITH FINAL ACCUMULATIONS AT MSP
STILL LOOKING LIKELY TO BE IN THE 2 TO 4 INCH RANGE.

/OUTLOOK FOR KMSP/
MON...MVFR/-SN ENDING EARLY...THEN VFR. WINDS W AT 15G25KTS.
TUE...VFR. WINDS W 15G25KTS.
WED...VFR. WINDS W 5-10KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ045-052-053-
     060>070-073>078-082>085-091>093.

     WIND CHILL WARNING UNTIL NOON CST TODAY FOR MNZ041>044-047>051-
     054>059.

WI...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-023>028.

&&

$$

UPDATE...MPG
SHORT TERM...JLT
LONG TERM...LS
AVIATION...MPG