000
FXUS63 KMPX 031817
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1217 PM CST TUE DEC 3 2013

.UPDATE...
ISSUED AT 1214 PM CST TUE DEC 3 2013

ALLOWED THE DENSE FOG ADVISORY ACROSS WEST CENTRAL THROUGH MUCH OF
SOUTH CENTRAL MN TO EXPIRE AT NOON. VISIBILITIES ARE SLOWLY
IMPROVING WITH AROUND 1 MILE FOR THE AFTERNOON. THE EXCEPTION IS
FOR FARIBAULT AND FREEBORN COUNTIES WHERE A DENSE FOG ADVISORY HAS
BEEN EXTENDED UNTIL NOON ON WEDNESDAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 446 AM CST TUE DEC 3 2013

AFTER SEVERAL DAYS OF HORRIBLE NCEP MODEL CONSISTENCY...CONFIDENCE
IN THIS WINTER STORM HAS INCREASED NOW THAT THE DEFIANT NAM AND GFS
FINALLY JUMPED ON BOARD WITH THE UKMET...GEM...AND ECMWF IN THEIR
06Z RUN. A WINTER STORM WARNING HAS BEEN POSTED FOR MUCH OF CENTRAL
AND WESTERN MINNESOTA WITH THIS FORECAST PACKAGE BEGINNING TONIGHT
AND RUNNING THROUGH WEDNESDAY NIGHT. MORE DETAILS SHORTLY.

EARLY THIS MORNING...WIDESPREAD DENSE FOG HAS FORMED ACROSS WESTERN
MINNESOTA...AND IT HAS BEEN SHOWING SIGNS OF THICKENING UP FURTHER
EAST TOWARD THE TWIN CITIES AND ALONG THE I-35 AND I-90 CORRIDORS.
WE MAY NEED TO EXPAND THE DENSE FOG ADVISORY EASTWARD SHORTLY. THE
FOG WILL BE SLOW TO IMPROVE WITH THE LOW SUN ANGLE AND WIDESPREAD
CLOUDS TODAY. IN FACT...THE LAMP GUIDANCE IS KEEPING IT AROUND
THROUGH THE DAY. ONE THING THAT MAY HELP THE FOG TO IMPROVE WILL BE
OCCASIONAL LIGHT RAIN/SNOW DEVELOPING LATER THIS MORNING. THE
ADVISORY CURRENTLY GOES THROUGH 9 AM...BUT IT WILL PROBABLY NEED TO
BE EXTENDED AT LEAST INTO THE EARLY AFTERNOON.

WEAK ISENTROPIC LIFT IN A VERY MOIST ATMOSPHERE WILL BRING
OCCASIONAL LIGHT RAIN AND SNOW ACROSS THE ENTIRE AREA TODAY AND THIS
EVENING. INCREASED POPS TO CATEGORICAL TODAY AND THIS EVENING...BUT
AMOUNTS WILL BE LIGHT. ONLY EXPECTING AN INCH OR TWO OF SNOW TODAY
AND THIS EVENING BEFORE THE MAIN ROUND BEGINS LATER TONIGHT.

BY TONIGHT...THE TROUGH DIGGING INTO THE FOUR CORNERS REGION WILL
BRING A DEVELOPING SURFACE LOW FROM OKLAHOMA TONIGHT INTO EASTERN
IOWA WEDNESDAY. THE SYSTEM WILL BE UNDERGOING A NEGATIVE TILT
TRANSITION AND WIDESPREAD SNOW WILL DEVELOP ON THE BACKSIDE OF THE
LOW...ENVELOPING THE AREA FROM SOUTHWEST TO NORTHEAST LATE TONIGHT. THE
SNOW COULD BECOME HEAVY AT TIMES BY WEDNESDAY MORNING. ACCUMULATIONS
LATE TONIGHT WILL RANGE FROM 1 TO 3 INCHES...EXCEPT ACROSS FAR
SOUTHERN MN AND WESTERN WI WHERE THERMAL PROFILES WILL PROMOTE MORE
OF A MIX. HERE...A HALF INCH CAN BE EXPECTED. AS MENTIONED
BEFORE...NCEP MODELS HAVE FINALLY SNAPPED IN LINE AND CONFIDENCE HAS
INCREASED SUCH THAT A WARNING WAS PRUDENT.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 446 AM CST TUE DEC 3 2013

LONG TERM BEGINS WITH THE BRUNT OF THE WINTER STORM OVER THE AREA
WEDNESDAY...INTO WEDNESDAY NIGHT. FOLLOWING BEHIND THE STORM WILL BE
STRONG NORTHWEST WINDS...WHICH WILL CAUSE SIGNIFICANT BLOWING AND
DRIFTING SNOW IN THOSE AREAS RECEIVING THE SNOW. TEMPERATURES
WILL DROP OFF SHARPLY WEDNESDAY NIGHT AND THE COLDEST AIR OF THE
SEASON WILL AFFECT THE AREA FOR THE REMAINDER OF THE WEEK.

MODELS ARE FINALLY COMING INTO SOME FORM OF CONSENSUS. IT TOOK THE
GFS UNTIL THE 06Z.03 RUN TO DO IT. THE SURFACE CYCLONE DEVELOPS TO
THE LEE OF THE ROCKIES/OKLAHOMA PANHANDLE TONIGHT AND WILL LIFT
NORTHEAST AND DEEPEN OVER CENTRAL WISCONSIN WEDNESDAY. THERE WAS A
WOBBLE IN THE 00Z ECMWF...WHICH DID LIFT THE SURFACE LOW EVER SO
SLIGHTLY TO THE WEST. IT LIFTED ITS QPF A BIT FARTHER TO THE WEST
AS WELL. THE OTHER MODELS HAVE TRENDED TO MORE SOUTHWEST TO EAST
CENTRAL MN...INTO NORTHWEST WISCONSIN. AS THE LOW LIFTS NORTHEAST
INTO WISCONSIN ...THERE MAY BE A WINTRY MIX AFFECTING A PORTION OF
WEST CENTRAL WISCONSIN IN THE MORNING...BUT WILL SWITCH OVER TO
JUST SNOW IN THE AFTERNOON...AS DYNAMICS TAKE OVER AND COOLS THE
COLUMN. THE STRONG NORTHWEST WINDS FOLLOWING THE LOW WILL GENERATE
BLOWING AND DRIFTING SNOW AND NEAR BLIZZARD CONDITIONS IN OUT
STATE MINNESOTA WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. THE
HEAVIER SNOW WILL AFFECT THE MINNESOTA PORTION OF THE CWA
WEDNESDAY AND LIFT NORTHEAST OVER THE NORTHEAST CWA LATE
AFTERNOON...AND WEDNESDAY EVENING. LOOKS LIKE A GOOD 6-9 INCH SNOW
IN THE HEAVIER SNOW BAND.

FOLLOWING THE STORM...ARCTIC AIR WILL BE DRAWN EAST OVER THE AREA
THROUGH THE REMAINDER OF THE WEEK.. WIND CHILLS MAY BECOME AN
ISSUE THURSDAY NIGHT AND FRIDAY. THE LONGER TERM MODELS WERE IN
FAIR AGREEMENT WITH ANOTHER TROUGH AFFECTING THE REGION OVER THE
WEEKEND. THIS WILL HAVE TO MONITORED AS WELL...WITH VERY HIGH
SNOW/LIQUID RATIOS. VERY COLD AIR DRAINS SOUTH AFTER THIS SYSTEM
AS WELL.  IT APPEARS WINTER IS HERE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1132 AM CST TUE DEC 3 2013

SOLID IFR WITH OCCASIONAL LIFR LOOKS LIKE THE RULE THROUGH THE
FORECAST PERIOD AS AN INVERTED TROUGH LINGERS OVER THE AREA WHILE
THE MAIN SURFACE LOW GETS ITS ACT TOGETHER AND LIFTS NORTHEAST. THE
MAIN FORECAST ISSUES ARE THE TIMING OF HEAVIER PCPN... AND FOR THE
SOUTHERN AND EASTERN LOCATIONS THE FORM THE PCPN WILL TAKE. KEPT
CEILINGS VISIBILITIES FAIRLY CONSISTENT... BUT WOULD EXPECT SOME
AMENDMENTS TO COVER PERIODIC IMPROVEMENT/REDUCTION AS PCPN MOVES
THROUGH THE REGION. TRIED TO BRACKET THE BEST GUESS PERIOD FOR
HEAVIER PCPN... BUT DIDN/T GO LOWER THAN 1/2SM ANYWHERE EVEN
THOUGH IT IS LIKELY WE/LL SEE SOME 1/4SM. FIGURE WE CAN ADJUST
DOWNWARD ONCE WE SEE THE WHITES... LITERALLY... OF ITS EYES
TONIGHT. INCLUDED SOME MIXED PCPN FOR KMSP... KEAU... AND KRNH
WITH THE WARM NOSE ALOFT LOOKING LIKE IT COULD IMPACT THOSE
SITES... ALTHOUGH THE NAM APPEARS A BIT TOO AMBITIOUS IN THAT
REGARD IN COMPARISON TO OTHER GUIDANCE. BUT... ONCE AGAIN THAT IS
SOMETHING THAT WILL NEED TO BE WATCHED THROUGH THE AFTERNOON AND
EVENING. WE SHOULD START TO SEE SOME IMPROVEMENT AFTER 18Z
TOMORROW AS THE SURFACE LOW GETS EAST AND EVENTUALLY NORTHEAST OF
THE AREA AND WE SEE SOME BETTER THERMAL ADVECTION.

KMSP...CONFIDENCE IS HIGH IN THE OVERALL FLIGHT CONDITIONS
FORECAST... BUT TIMING OF HEAVIER PCPN COULD VARY BY +/- MINUS 3
HOURS OR SO. IN ADDITION... WE COULD SEE A PERIOD OF MORE
PREDOMINANT SLEET DURING THE NIGHT IF THE WARM LAYER ALOFT MAKES
IT INTO THE AREA MORE THE EXPECTED. JUST INCLUDED A PERIOD OF THAT
FOR NOW... WITH A TRANSITION TO ALL SNOW... BUT THAT IS SOMETHING
THAT WILL BEAR WATCHING.

/OUTLOOK FOR KMSP/
WEDNESDAY NIGHT...MVFR CEILING EXPECTED WITH MVFR VISIBILITIES
POSSIBLE EARLY WITH A CHANCE OF SNOW. NORTHWEST WIND 15 TO 25 KT.
THURSDAY...MVFR CEILINGS POSSIBLE. NORTHWEST WIND 10 TO 20 KT.
THURSDAY NIGHT...VFR. WEST WIND 5 TO 15 KT.
FRIDAY...MVFR CEILING POSSIBLE. WEST WIND 5 TO 15 KT.
FRIDAY NIGHT...VFR. WEST WIND LESS THAN 10 KT.
SATURDAY...VFR. VARIABLE WIND 5 KT OR LESS.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 AM CST
     THURSDAY FOR MNZ069-070-076>078-082>085.

     WINTER STORM WARNING FROM 9 PM THIS EVENING TO 6 AM CST THURSDAY
     FOR MNZ041>045-047>068-073>075.

     DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR MNZ092-093.

WI...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 AM CST
     THURSDAY FOR WIZ024>028.

     WINTER STORM WARNING FROM 9 PM THIS EVENING TO 6 AM CST THURSDAY
     FOR WIZ014>016-023.

&&

$$

UPDATE...RAH
SHORT TERM...BORGHOFF
LONG TERM...DWE
AVIATION...