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000
FXUS63 KMPX 060453
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1053 PM CST THU DEC 5 2013

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 412 PM CST THU DEC 5 2013

ONE WORD SUMS UP THE SHORT TERM...COLD. ARCTIC HIGH PRESSURE WILL
CONTINUE TO BUILD OVER THE REGION WITH THE CENTER OF THE HIGH
NOT OVER THE FA UNTIL SATURDAY. HENCE...THERE WILL BE A SURFACE
PRESSURE GRADIENT THAT WILL KEEP A BRISK WESTERLY WIND IN PLACE
TONIGHT WITH THE WIND SPEED A LITTLE LESS ON FRIDAY. VERY LITTLE
CHANGE TO THE LOW AND HIGH TEMPERATURE FORECASTS WERE MADE TODAY
AS THEY WERE PRETTY MUCH OF THE LOW SIDE OF GUIDANCE. ABOUT THE
ONLY ONE LOWER WAS THE ECE WHICH WAS A LITTLE SURPRISING AS THE
GEM IS USUALLY ON THE COLD SIDE IN THIS PATTERN. GIVEN THE COLD
AND WIND...APPARENT TEMPERATURES LOWER QUICKLY TO MINUS 25 THIS
EVENING ACROSS WESTERN MINNESOTA AND TO NEAR MINUS 35 BY FRIDAY
MORNING... WHILE EASTERN AREAS ARE MORE NEAR MINUS 25 FRIDAY
MORNING. EASTERN AREAS RECOVER SOME ON FRIDAY WHILE WESTERN
MINNESOTA REMAINS NEAR MINUS 25. THEREFORE...THE TIMING WITH THE
WIND CHILL ADVISORY REMAINS OKAY.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 412 PM CST THU DEC 5 2013

THE LONG TERM PERIOD CAN BE SUMMED UP WITH ONE WORD...COLD. THERE
WILL BE A COUPLE OF CHANCES FOR LIGHT SNOW WITH PASSING UPPER
WAVES SUN EVENING AND AGAIN MONDAY NIGHT. REALLY FOR THE NEXT
WEEK...WE WILL BE LUCKY TO SEE HIGHS CRACK THE 10 ABOVE
MARK...WITH NO SIGNS OF ANY SORT OF JUST MODEST WARMUP UNTIL THIS
TIME NEXT WEEK. WITH TEMPERATURES AS COLD AS THEY ARE EXPECTED TO
BE...THE MAIN WEATHER HAZARD FOR THE NEXT WEEK WILL BE DANGEROUS
WIND CHILLS...WITH VALUES EXPECTED TO DROP TO AT LEAST 20 BELOW
MANY NIGHTS...WITH WIND CHILL VALUES LESS THAN 30 BELOW POSSIBLE A
FEW OF THOSE NIGHTS AS WELL.

STARTING WITH PRECIP CHANCES...THE FIRST WILL COME MAINLY SUNDAY
AFTERNOON INTO SUNDAY NIGHT. CURRENTLY...THE WAVE THAT WILL BE
RESPONSIBLE FOR THIS SNOW IS NOTHING MORE THAN A JET STREAK RACING
DOWN TO COAST OF BRITISH COLUMBIA. ON FRIDAY...THE WAVE WILL
AMPLIFY AS IT IS DIVING SOUTH ALONG THE WEST COAST OF THE CONUS.
ALL MODELS IN GOOD AGREEMENT WITH THIS WAVE DIGGING INTO THE
DESERT SW SATURDAY...THEN EJECTING ENE ACROSS THE PLAINS SUNDAY.
H85 WINDS WILL TURN OUT OF THE SOUTH AHEAD OF THE WAVE...WITH A
BAND OF ISENTROPIC SNOW EXPECTED TO WORK OUT OF NEBRASKA ON SUNDAY
AND INTO WI/MI BY MONDAY MORNING. UNLIKE THE SYSTEM THAT PASSED
EARLIER THIS WEEK...THERE WILL BE NO GULF MOISTURE TO WORK
WITH...WHICH IS EVIDENT BY THE FACT THAT SPEC HUMIDITIES ON THE
275/280K SFCS ARE PEGGED TO ONLY BE BETWEEN 1 AND 1.5 G/KG. THE
GARCIA METHOD WOULD SAY THIS IS GOOD FOR 2-3 INCHES OF
SNOW...THOUGH THIS COULD BE ENHANCED BY THE FACT THAT THE
DENDRITIC GROWTH ZONES LOOK DEEP WITH THIS SYSTEM...WHICH WILL
LIKELY ALLOW SNOW RATIOS TO EXCEED 20:1...ENHANCING POSSIBLE
SNOWFALL AMOUNTS BY AN INCH OR TWO. DETERMINISTIC GUIDANCE SIMILAR
WITH TAKING THE MOST QPF AND THEREFORE LARGEST SNOWFALL AMOUNTS
ACROSS IOWA INTO CENTRAL WI. FOR THE MPX CWA...THIS SHOULD
TRANSLATE TO 1 TO 3 INCHES OF SNOW SOUTHEAST OF ABOUT A REDWOOD
FALLS TO MORA LINE. OF INTEREST WITH THIS SYSTEM THOUGH IS HOW FAR
NW THE SREF MEAN QPF IS OF THE DETERMINISTIC RUNS. LOOKING AT THE
POSTAGE STAMPS...THIS IS DUE TO THE FACT THAT THE 7 ARW MEMBERS
ARE DEPICTING A MUCH DEEPER SURFACE LOW THAN THE DETERMINISTIC
MODELS /ON THE ORDER OF 10 MB/ THAT GOES FROM IOWA INTO WI SUNDAY
EVENING...WHILE THE DETERMINISTIC MODELS SHOW A MORE DIFFUSE SFC
LOW WORKING FROM AROUND ST. LOUIS UP INTO MICHIGAN...WITH NOTHING
MORE THAN AN INVERTED TROUGH WORKING ACROSS THE MPX AREA. GIVEN
THE FACT THAT THIS LOW WILL BE TRYING TO DISPLACE A 1040 MB
HIGH...HARD TO PUT TO MUCH CONFIDENCE IN THOSE ARW MEMBERS...SO AT
THIS POINT ABOUT THE ONLY GUIDANCE THAT WAS AVOIDED WAS THE SREF.

FOR THE MONDAY NIGHT SYSTEM...THIS LOOKS EVEN MORE ANEMIC THAN THE
WAVE FOR SUNDAY EVENING. THE MONDAY NIGHT WAVE WILL BE
ASSOCIATED WITH A LOBE OF THE POLAR VORTEX SWINGING THROUGH THE
AREA AND LOOKS TO BE A CLIPPER TYPE SYSTEM IN DEVELOPING NW FLOW
THAT AT THIS POINT LOOKS LIKE IT WILL STRUGGLE TO PRODUCE EVEN AN
INCH OF SNOW AS THE MEAGER MOISTURE WE DID HAVE WILL BE SWEPT AWAY
WITH THE MONDAY EVENING SYSTEM.

FOR TEMPERATURES...H85 TEMPS LOOKS TO REMAIN AROUND -20C THROUGH
SATURDAY NIGHT. THEY THEN BRIEFLY MODIFY UP TO A WHOPPING -16C
AHEAD OF THE WEAK SAVES FOR SUNDAY/MONDAY. AS MENTIONED
EARLIER...THE MONDAY NIGHT WAVE IS ASSOCIATED WITH A LOBE OF THE
POLAR VORTEX...AND IN ITS WAKE...THE GFS/ECMWF SHOW H85 TEMPS
CRASHING TO AROUND -24C. WHAT THIS MEANS FOR TEMPERATURES IS THAT
SUNDAY AND MONDAY WILL LIKELY BE OUR BEST CHANCES FOR SEEING HIGHS
GET ABOVE 10. THOUGH CURRENT FORECAST HIGHS/LOWS ARE PLENTY COLD
ENOUGH FRIDAY THROUGH SATURDAY NIGHT...THEY ARE STILL AROUND 5
DEGREES WARMER THAN WHAT THE ECMWF AND ITS AFFILIATED MOS GUIDANCE
HAVE...SO WE MAY NOT BE COLD ENOUGH. IN FACT...THE ECMWF SHOWS AXN
DROPPING BELOW ZERO TONIGHT AND IT DOES NOT SHOW AXN GOING BACK
ABOVE ZERO UNTIL SUNDAY AFTERNOON. AS FOR MID-WEEK...IF WE DO IN
FACT SEE H85 TEMPS MAKE A RUN FOR -25C...THEN YOU CAN PROBABLY
KNOCK A GOOD 10 DEGREES OF CURRENT HIGHS/LOWS FOR TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT.

LOOKING BEYOND THIS FORECAST PERIOD...THE ECMWF DOES FINALLY SHOW
H5 HEIGHTS AND H85 TEMPS MODERATING SOME BY THE END OF THE NEXT
WEEK...BRINGING TEMPERATURES THAT ARE BACK UP TO WITHIN 5 DEGREES
OF NORMAL...AS OPPOSED TO DOWN AROUND 20 TO 30 DEGREES BELOW.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1051 PM CST THU DEC 5 2013

ALL SITES EXPECTED TO REMAIN AS VFR THRU TMRW WITH ARCTIC HIGH
PRES MOVG IN FROM THE NW. FEW/SCT CLOUDS WILL REMAIN IN THE
1500-2000FT RANGE. THERE IS SOME MODEL INDICATION THAT A MIDLVL
BKN LAYER...IN TEH 3-5 KFT RANGE...MAY DEVELOP MIDDAY BUT AM
THINKING THIS IS AGAIN IN RESPONSE TO ICE CRYSTALS AND NOT A TRUE
CLOUD LAYER SO WILL CONTINUE TO RUN WITH VFR BUT WILL MONITOR SUCH
A DEVELOPMENT. W TO WNW WINDS THROUGHOUT...WITH SPEEDS IN THE
8-10 KT RANGE.

KMSP...VFR CONDS THROUGH WITH FEW/SCT CLOUDS LINGERING ARND 2 KFT
THROUGHOUT. W TO WNW WINDS ARND 10 KT.

/OUTLOOK FOR KMSP/
SAT...VFR. VARIABLE WIND 5 KTS OR LESS.
SAT NIGHT...VFR. S WIND 5 KTS OR LESS.
SUN AND SUN NIGHT...MVFR CONDS EXPECTED WITH -SN LIKELY. IFR
CONDS POSSIBLE. SE WIND 5-10 KTS SHIFTING W.
MON...MVFR CIGS POSSIBLE EARLY. W WIND 10-20 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL 9 AM CST FRIDAY FOR MNZ044-045-051>053-
     059>063-066>070-074>078-082>085-091>093.

     WIND CHILL ADVISORY FROM 6 PM FRIDAY TO 9 AM CST SATURDAY FOR
     MNZ044-045-051>053-059>063-066>070-074>078-082>085-091>093.

     WIND CHILL ADVISORY UNTIL NOON CST SATURDAY FOR MNZ041>043-
     047>050-054>058-064-065-073.

WI...WIND CHILL ADVISORY UNTIL 9 AM CST FRIDAY FOR WIZ014>016-023>028.

     WIND CHILL ADVISORY FROM 6 PM FRIDAY TO 9 AM CST SATURDAY FOR
     WIZ014>016-023>028.

&&

$$

SHORT TERM...RAH
LONG TERM...MPG
AVIATION...JPC