Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 250010 AAA
AFDMPX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
610 PM CST MON NOV 24 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 249 PM CST MON NOV 24 2014
ISSUED BY NATIONAL WEATHER SERVICE LA CROSSE WI

CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A POTENT TROUGH COMING INTO CENTRAL BRITISH COLUMBIA ON TOP
OF EAST PACIFIC RIDGING...AND MORE TROUGHING COVERING MUCH OF
CENTRAL NORTH AMERICA. WITHIN THIS BROAD TROUGH...A SHORTWAVE WAS
PRESENT OVER EASTERN IOWA/NORTHERN IL...WHICH DPVA FROM IT COMBINED
WITH A BAND OF MID LEVEL FRONTOGENESIS HAS ALLOWED A BAND OF SNOW TO
PERSIST FROM WESTERN INTO SOUTHERN WI. ADDITIONAL SNOW SHOWERS HAVE
BEEN TAKING PLACE ACROSS MUCH OF MN INTO IA...MOSTLY ASSOCIATED WITH
INSTABILITY PRODUCED FROM COOL MID LEVEL TEMPS ALOFT AND RELATIVELY
WARMER TEMPS/DEWPOINTS AT THE SURFACE. RAP 700MB TEMPS SHOWED
READING IN THE -12 TO -13C RANGE...MEANWHILE SURFACE TEMPS HAVE
COOLED INTO THE TEENS AND 20S...WARMEST IN WESTERN WI. A TIGHT
PRESSURE GRADIENT IN PLACE...BETWEEN A SURFACE RIDGE OVER THE
WESTERN PLAINS AND A LOW PRESSURE TROUGH IN NORTHERN LOWER MI...HAS
PRODUCED GUSTS OF 30-40 MPH. THE STRONGEST GUSTS HAVE BEEN CONFINED
TO SOUTHWEST AND SOUTH CENTRAL MN WHERE THE DEEPEST MIXING HAS BEEN
TAKING PLACE. FARTHER TO THE WEST...A LARGE EXPANSE OF CLEARING
DOMINATES A LOT OF THE PLAINS...ASSOCIATED WITH THE SURFACE RIDGE
AND VERY DRY AIR. PRECIPITABLE WATER VALUES THERE ARE IN THE 0.1-0.2
INCH RANGE.

THE FOCUS FOR ATTENTION BEGINS TO SHIFT TO THAT POTENT TROUGH OVER
CENTRAL BRITISH COLUMBIA. GOOD MODEL CONSENSUS EXISTS FOR THE TROUGH
TO DIG DOWN INTO THE WESTERN DAKOTAS BY 00Z WEDNESDAY...ALLOWING
WEAK RIDGING TO BUILD OVER THE FORECAST AREA. ADDITIONALLY...THE
NEXT POTENT TROUGH WILL HELP PUSH THE CURRENT SHORTWAVE TROUGH AND
700MB COOL AIR SITUATED OVER THE FORECAST AREA OFF TO THE EAST.

FOR TONIGHT...ANTICIPATING SNOW SHOWERS OVER MINNESOTA TO DIMINISH
QUICKLY THIS EVENING WITH LOSS OF DAYTIME HEATING. FIGURE
SOMEWHERE AROUND 03Z THEY SHOULD HAVE ENDED...IN AGREEMENT WITH A
LOT OF HI RESOLUTION MODEL GUIDANCE. THE SNOW OVER WESTERN WI WILL
TAKE LONGER TO END BEING ASSOCIATED WITH THE MID LEVEL
FRONTOGENESIS BAND THERE...SOMEWHERE AROUND 06Z. CURRENT WINTER
WEATHER ADVISORY END TIME STILL LOOKS GOOD. REGARDING THE WIND
ADVISORY...PRESENT WINDS ARE MARGINAL TO KEEP IT GOING.
HOWEVER...SINCE CONDITIONS REMAIN BRISK FOR THE REST OF THE
AFTERNOON AND WINDS ARE STILL ON TRACK TO DIMINISH THIS
EVENING...PLAN ON LETTING THE WIND ADVISORY EXPIRE AT 6 PM. CLEARING
ACROSS THE PLAINS SHOULD MAKE ITS WAY WEST TO EAST ACROSS A LOT OF
THE FORECAST AREA...PERHAPS EVEN INTO WESTERN WI BY 12Z. THE
CLEARING COMBINED WITH A WEAKENING PRESSURE GRADIENT AND ALREADY
COOL TEMPERATURES SHOULD ALLOW READINGS TO DIP INTO THE SINGLE
DIGITS OVER WEST-CENTRAL MN. TEENS ARE LIKELY ELSEWHERE WITH MORE
CLOUDS AND WIND. IT SHOULD BE NOTED THAT MORE CLOUDS ARE LIKELY TO
COME INTO WESTERN SECTIONS OF THE FORECAST AREA BY 12Z...AHEAD OF
THE APPROACHING POTENT TROUGH.

ON TUESDAY...CLOUDS WILL MARCH THEIR WAY WEST TO EAST ACROSS THE
FORECAST AREA AGAIN AS THE POTENT TROUGH MOVES INTO THE WESTERN
DAKOTAS. ANY PRECIPITATION DOES LOOK TO REMAIN TO THE WEST PRIOR TO
00Z WEDNESDAY...THOUGH. ALTHOUGH THERE MIGHT BE MORE CLOUDS...
INCREASING SOUTHWESTERLY FLOW AHEAD OF THE AFTERNOON SHOULD HELP
GIVE TEMPERATURES A BOOST. IN FACT...925MB READINGS CLIMB FROM
AROUND -10C AT 12Z TO -4 TO -7C BY 00Z...WARMEST NEAR MANKATO AND
NEW ULM. MOST LOCATIONS SHOULD SEE HIGHS IN THE 20S...WITH 30S
POSSIBLE NEAR THE MN RIVER.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 249 PM CST MON NOV 24 2014
ISSUED BY NATIONAL WEATHER SERVICE LA CROSSE WI

MAIN FOCUS STARTING OFF THE PERIOD IS THE POTENT SHORTWAVE TROUGH
CURRENTLY IN CENTRAL BRITISH COLUMBIA. THERE HAS BEEN A MAJOR TREND
OVER THE PAST 2 DAYS TO DIG THIS TROUGH FARTHER SOUTHWEST...
ESPECIALLY IN THE ECMWF. THIS TREND APPEARS TO BE RELATED TO THE
CURRENT CENTRAL NORTH AMERICA TROUGH BEING MORE AMPLIFIED THAN
PREVIOUSLY PROGGED. AS A RESULT OF THIS TREND...THERE IS A CHANCE
SUGGESTED BY THE 24.12Z GFS THAT MUCH OF THE AREA COULD BE MISSED BY
THIS SYSTEM. THIS WOULD BE GOOD NEWS FOR TRAVELERS. IN THE GFS...THE
SHORTWAVE TROUGH AND ITS ASSOCIATED SURFACE LOW DIVE DOWN TO NEAR
THE KANSAS CITY AREA BY 12Z...WITH THE ISENTROPIC LIFT/MID LEVEL
FRONTOGENESIS ZONE BRUSHING THE MN RIVER VALLEY WITH SOME SNOW
BETWEEN 06-18Z WEDNESDAY. HAVE TRENDED THE FORECAST DRIER TO ACCOUNT
FOR THE MODEL TREND...BUT QPF AND POPS MAY NEED TO BE REDUCED
FURTHER. TEMPERATURES SHOULD NOT DROP MUCH TUESDAY NIGHT WITH THE
CLOUDS IN PLACE AND EVEN SOME SLIGHT WARM ADVECTION POSSIBLE. FOR
WEDNESDAY...HIGHS ARE LIKELY TO OCCUR BY NOON AS COLD ADVECTION
LOOKS TO COMMENCE IN THE WAKE OF THE TROUGH. THE AMOUNT OF ADVECTION
DEPENDS ON HOW FAR SOUTH THE TROUGH DIGS...THUS THESE READINGS ARE
SUBJECT TO CHANGE.

DRY AND COLDER CONDITIONS REMAIN PROGGED TO AFFECT THE AREA FOR
WEDNESDAY NIGHT AND THANKSGIVING...AS ARCTIC HIGH PRESSURE MOVES IN
FROM THE NORTHWEST. 925MB TEMPS TOPPING OUT IN THE -10 TO -16C RANGE
WILL ONLY ALLOW FOR HIGHS IN THE TEENS.

A PATTERN CHANGE IS IN THE OFFERING FOR THURSDAY NIGHT INTO EARLY
NEXT WEEK WITH MODELS ADVERTISING A SERIES OF TROUGHS MOVING INTO
THE WESTERN U.S.. THIS RESULTS IN A MORE ZONAL FLOW PATTERN
DOWNSTREAM TO EVENTUALLY SOUTHWESTERLY EARLY NEXT WEEK. THE SWITCH
TO ZONAL FLOW RESULTS IN A WARM ADVECTION REGIME THURSDAY NIGHT AND
FRIDAY. ON THE NOSE OF THE WARM ADVECTION...A MID-LEVEL
FRONTOGENESIS SNOWFALL BAND LOOKS TO SETUP FROM THE DAKOTAS THROUGH
MINNESOTA AND WISCONSIN. EXACT PLACEMENT AND AMOUNTS ARE YET TO BE
DETERMINED...BUT THE FOCUS RIGHT NOW GENERALLY APPEARS ALONG/NORTH
OF I-94. THE WARM FRONT LOOKS TO LIFT THROUGH MUCH OF THE FORECAST
AREA FRIDAY NIGHT. THEN FOR SATURDAY...A SHORTWAVE CROSSES THE AREA
IN THE ZONAL FLOW...SENDING A COLD FRONT THROUGH. THIS PERIOD COULD
BE TRICKY FOR HIGHS. IF THE FRONT IS SLOWER...HIGHS COULD EASILY TOP
OUT IN THE 40S. HOWEVER...AT THE CURRENT SPEED...UPPER 20S TO MID
30S SEEM MORE REASONABLE. DESPITE THE ZONAL FLOW...AN ARCTIC LOW
LEVEL INTRUSION LOOKS TO AFFECT THE AREA FOR SATURDAY NIGHT AND
SUNDAY...ACCOMPANIED BY ARCTIC HIGH PRESSURE...NOTED BY 925MB TEMPS
ABOUT 5C COLDER THAN AT 850MB. THOSE 925MB TEMPS ON SUNDAY RANGING
FROM -10 TO -15C MEANS BACK TO HIGHS IN THE TEENS. WE SHOULD BEGIN
TO DISLODGE THE COLD AIR ON MONDAY WITH THE UPPER FLOW TURNING
SOUTHWESTERLY...ALLOWING FOR A REBOUND BACK INTO THE 20S FOR HIGHS.
CONDITIONS LOOK TO REMAIN DRY FOR MONDAY WITH ARCTIC HIGH PRESSURE
IN PLACE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 610 PM CST MON NOV 24 2014

MVFR CIGS ARE IN PLACE OVER THE MAJORITY OF MINNESOTA AND
WISCONSIN...BUT CLEARING IS STARTING TO PUSH EASTWARD INTO WESTERN
MINNESOTA. THIS TREND WILL CONTINUE THROUGH THE NIGHT WITH VFR
CONDITIONS GRADUALLY RETURNING. THE SNOW HAS ABOUT ENDED...BUT A FEW
FLURRIES CANNOT BE RULED OUT ACROSS WI AND SRN MN. SOME MVFR CIGS
COULD RETURN LATE SATURDAY AS ANOTHER SYSTEM APPROACHES. WINDS WILL
EASE THIS EVENING AND BECOME LIGHT/VARIABLE TUESDAY AFTERNOON.

KMSP...BEST TIMING FOR VFR CONDITIONS IS ABOUT 06Z...BUT IT COULD
COME A BIT EARLIER. SOME HIGH/MID LEVEL CLOUDS MAY STICK AROUND
TUESDAY MORNING BEFORE LOWER MVFR CLOUDS RETURN LATE TUESDAY.

/OUTLOOK FOR KMSP/
WED...MVFR/IFR CHC -SN EARLY. WINDS NW 10-15KTS.
THU...VFR. WINDS LIGHT/VARIABLE.
FRI...VFR/CHC MVFR AND -SN. WINDS S 5 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ016-
     026>028.

&&

$$

SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BORGHOFF







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