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000
FXUS63 KMPX 052213
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
413 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 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1200 PM CST THU DEC 5 2013

MAINLY VFR CONDITIONS THROUGH THE FORECAST PERIOD AS ARCTIC HIGH
PRESSURE SLOWLY BUILDS IN FROM THE NORTHWEST. A TIGHT SURFACE PRESSURE
GRADIENT WILL EXIST THROUGH FRIDAY WITH RATHER BRISK WESTERLY
WINDS CONTINUING. SCT-BKN CU ARE OCCURRING AROUND AND TO THE NORTH
OF KEAU...BUT OBSERVATIONS OF BKN-OVC MVFR CEILINGS ACROSS
CENTRAL MN ARE MORE LIKELY THE RESULT OF SNOW BEING LIFTED BY THE
STRONG VIA WEB CAM DATA. HENCE...IT/S SOMEWHAT OF AN ARTIFICIAL
CEILING. THE MVFR VSBYS IN THE THESE AREAS ARE OCCURRING WITH THE
BLOWING SNOW.

KMSP...EXPECT VFR CONDITIONS THROUGH THE PERIOD WITH ONLY SCT CU.
WEST WINDS THIS AFTERNOON (270-280) 18G24KTS. A LITTLE MORE NW
COMPONENT ON FRIDAY (290-300) WITH SPEEDS 10-12KTS.

/OUTLOOK FOR KMSP/
FRIDAY NIGHT...VFR. WNW WIND LESS THAN 10 KTS.
SATURDAY...VFR. VARIABLE WIND 5 KTS OR LESS.
SATURDAY NIGHT...VFR. SOUTH WIND 5 KTS OR LESS.
SUNDAY AND SUNDAY NIGHT...MVFR CEILINGS AND VISIBILITIES EXPECTED
WITH SNOW LIKELY. IFR CONDITIONS POSSIBLE. SOUTHEAST WIND 5 TO 10 KTS
SHIFTING WEST.
MONDAY...MVFR CEILINGS POSSIBLE EARLY. WEST WIND 10 TO 20 KTS.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 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 FROM 9 PM THIS EVENING TO 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...RAH