Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 142114
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
414 PM CDT MON APR 14 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 252 PM CDT MON APR 14 2014

COLD CANADIAN AIR MASS CONTINUED TO FILTER SOUTHWARD ACROSS THE
UPPER MIDWEST WITH 85H TEMPS NEARLY TWO STANDARD DEVIATIONS BLW
NORMAL FOR MID APRIL. EVEN WITH A HIGH ANGLE APRIL SUN...TEMPS
HAVE STRUGGLED TO REACH 40 DEGREES. THERE WERE EVEN SOME TEMPS BLW
FREEZING STILL AS OF 2 PM. A FAST MOVING DISTURBANCE ACROSS THE
DAKOTAS HAS BROUGHT SOME CLOUDINESS THIS AFTN...WHICH WILL QUICKLY
DISSIPATE BY EARLY EVENING...SETTING THE STAGE FOR TEMPS DROPPING
INTO THE 20S...AND TEENS BY EARLY MORNING. BRISK NORTHWEST WINDS
WILL DROP OFF AFTER SUNSET...SO WIND CHILL VALUES WILL NOT BE AS
COLD. A LATE WINTER STORM IS IN THE DEVELOPMENT FOR MID WEEK...BUT
TUESDAY WILL BE SUNNY WITH INCREASING SOUTHEAST WINDS AHEAD OF THE
MID WEEK SYSTEM. TUESDAY AFTN HIGHS WILL LIKELY REMAIN WELL BLW
NORMAL WITH READINGS STRUGGLING TO RISE INTO THE 40S.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 252 PM CDT MON APR 14 2014

VERY ACTIVE PATTERN OVER THE AREA DURING THIS EXTENDED PORTION...
INCLUDING THE POTENTIAL FOR ACCUMULATING WET SNOW DURING THE
MIDDLE PORTION OF THE WEEK WITH WELL BELOW NORMAL TEMPERATURES
FOLLOWED BY SIGNIFICANT WARMING OVER THE UPCOMING WEEKEND TO
NEAR NORMAL TEMPERATURES.

TUESDAY NIGHT THRU WEDNESDAY NIGHT...WITH COLD AIR ALREADY
RESIDENT OVER THE AREA /-5 TO -10 DEG C AT THE START OF THE
PERIOD/...A CLIPPER-TYPE LOW PRES CENTER WILL DROP SE FROM WRN
CANADA INTO THE NRN PLAINS. THIS SFC LOW IS TRAVERSING UNDER A
STRONG WNW-ESE UPR LVL FLOW THAT WILL BRING IT OVER THE DAKOTAS
WED NIGHT. HELPING TO NUDGE THIS SFC SYSTEM ALONG IS A SHORTWAVE
TROF AXIS...WHICH WILL DIG DEEPER OVER THE CENTRAL PLAINS AND MID-
MISSISSIPPI RIVER VALLEY WED AND WED NIGHT...ALLOWING FOR
ADDITIONAL LIFT AS THE SFC LOW DEEPENS. MOISTURE WITH THIS SYSTEM
WILL BE CONCENTRATED ON ITS NRN AND ERN PORTIONS...WHICH WILL MAKE
THE PRECIP START ACRS THE MPX CWFA LATE TUE NIGHT THEN INCREASE IN
INTENSITY AND COVERAGE WED AND WED NIGHT. WITH NEUTRAL TO
POTENTIALLY COLD AIR ADVECTION DUE TO THE PASSAGE OF THIS
SYSTEM...TEMPERATURES WILL HAVE LITTLE CHANCE TO RISE ABOVE
FREEZING FOR MUCH OF THE NRN PORTIONS OF THE CWFA...BOTH IN
CENTRAL-ERN MN AND W-CENTRAL WI. ISENTROPIC LIFT STILL LOOKS
SIGNIFICANTLY ENHANCED FROM THE 290K THRU 300K SFCS IN ADVANCE OF
THIS SYSTEM ON MULTIPLE MODELS. TRANSLATING THIS TO SIGNIFICANT
WX...THIS MEANS THAT PRECIP STARTING OUT AS SNOW WILL HAVE A BRIEF
WINDOW WHERE IT WOULD MIX WITH RAIN OVER THE NRN TIER OF
COUNTIES...CONTINUING ITS ACCUMULATION...WHILE CENTRAL AND SRN
PORTIONS OF THE CWFA WILL MORE DEFINITIVELY TRANSITION TO RAIN.
HOWEVER...AS THIS SFC LOW SHIFTS ACRS THE REGION DURG THE DAY
WED...ADDITIONAL COLD AIR BEING DRAGGED INTO THE REGION ON ITS
BACKSIDE WILL FORCE THE P-TYPE BACK OVER TO ALL SNOW BY LATE DAY
WED AND CONTINUE THRU MUCH OF WED NIGHT BEFORE TAPERING OFF EARLY
MRNG THU. WITH THE PRECIP BEING -SN FOR THE LONGEST DURATION OVER
NRN PORTIONS OF THE CWFA...AND GROUND TEMPS RIGHT AROUND
FREEZING...THIS WILL ALLOW FOR GREATEST ACCUMULATIONS N OF THE
I-94 CORRIDOR. AMOUNTS IN EXCESS OF 3 INCHES...AND POTENTIALLY UP
TO AROUND 8 INCHES...ARE CERTAINLY POSSIBLE SO HAVE OPTED TO RAISE
A WINTER STORM WATCH FOR THE NRN AND NERN TIER OF COUNTIES. THIS
WILL VERY LIKELY BE A HEAVY WET SNOW DUE TO QPF IN THE 0.40-0.70
INCH RANGE IN THE AFOREMENTIONED NRN PORTIONS. HAVE BETTER
CONFIDENCE IN THE HIGHER QPF AND HIGHER SNOWFALL AMOUNTS DUE TO
VERY GOOD AGREEMENT AMONG THE 12Z MODEL RUNS OF THE GFS/GEM/EC AND
15Z SREF. PREVIOUSLY...THE 00Z EC WAS WELL BELOW ALL THE OTHER
MODELS BUT THIS LATEST RUN HAS COME RIGHT IN LINE WITH THE OTHER
MODELS...WHICH HAVE BEEN RELATIVELY CONSISTENT RUN-TO-RUN OVER THE
LAST SEVERAL MODEL RUNS. THE PRECIPITATION WILL GRADUALLY END FROM
W TO E ACRS THE CWFA EARLY THU MRNG WHILE TEMPERATURES DROP INTO
THE LWR TO MID 20S.

THURSDAY THRU FRI NIGHT...THE CLIPPER LOW WILL SHIFT OFF TO THE E
DURG THE DAY ON THU WHILE LEAVING A LINGERING QUASI-STNRY FRONT IN
ITS WAKE OVER MI-IL-MO. HIGH PRES TRAVERSING EWD OVER S-CENTRAL
CANADA WILL EXTEND SWD ACRS THE DAKOTAS-MN-WI DURG THE DAY ON
WED... RESULTING IN A DRY DAY WITH HIGHS IN THE UPR 30S TO ARND
40. THIS HIGH PRES SPOKE WILL QUICKLY SHIFT E WHILE THE STNRY FNT
TO THE S SHIFTS N AS A WMFNT...IN ADVANCE OF ANOTHER LOW PRES
CENTER OVER THE TX/OK PANHANDLES. THIS LOW WILL REMAIN WELL S OF
THE AREA AS IT TURNS E AND NE THU NIGHT INTO FRI...BUT AGAIN
ENHANCED ISENTROPIC LIFT ALONG THE LINGERING FNT WILL BE ENOUGH TO
PRODUCE ISOLD TO SCTD -RA/-SN SHWRS THU NIGHT THRU EARLY FRI NIGHT
OVER MAINLY ERN PORTIONS OF THE CWFA. NOT LOOKING FOR MUCH IN THE
WAY OF QPF NOR SNOW ACCUMULATION...BUT THERE DOES LOOK TO BE SOME
LIGHT -SN THAT WILL FALL DURG THIS TIME.

SATURDAY THRU MONDAY...ANOTHER WEAK CLIPPER-TYPE SYSTEM WILL SHIFT
THROUGH THE REGION SAT INTO SUN UNDERNEATH A WELL-DEFINED
SHORTWAVE TROF. THIS ONE WILL ALSO PRODUCE A MIXTURE OF
-RA/-SN...BUT ALSO LIKE THE ONE FOR THU-FRI...THIS ONE WILL
PRODUCE LITTLE IN THE WAY OF QPF AND SNOW ACCUMULATION. THIS
SYSTEM DOES RIDE IN ON THE ERN FRINGES OF A LARGE BUILDING UPR LVL
RIDGE MOVG EWD FROM THE WRN CONUS FOR THE START OF NEXT WEEK. THIS
WILL TRANSLATE TO A VERY NOTICEABLE WARMING TREND FOR EARLY NEXT
WEEK WITH TEMPERATURES LIKELY RETURNING TO NEAR NORMAL LEVELS FOR
SUN AND ABOVE NORMAL LEVELS ON MON.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1141 AM CDT MON APR 14 2014

VFR CIGS ACROSS NORTHERN MN WILL DRIFT SOUTHWARD ACROSS MN THIS
AFTN...BUT SHOULD REMAIN AOA 4K. OTHERWISE...GUSTY NW/NNW WINDS UP
TO 25 KTS WILL DECREASE AFT 23-00Z WITH SPDS LESS THAN 7 KTS BY
2-4Z. WIND SPDS WILL REMAIN UNDER 7 KTS THRU 18Z TUESDAY...BUT
SLOWLY BECOME SE IN WC MN...TO SW IN WC WI.

KMSP...A FEW CLDS POSSIBLY CIGS ARND 5K TO 9K THIS AFTN WITH
GUSTY NW/NNW WINDS UP TO 25 KTS AT TIMES. WINDS WILL DECREASE AFT
23-01Z...AND BECOME LESS THAN 7 KTS BY 2-4Z FROM THE NW. WINDS
WILL SHIFT TO THE SW BY TUESDAY MORNING...BUT REMAINING UNDER 7
KTS UNTIL AFT 00Z/16.

/OUTLOOK FOR KMSP/
WED...MVFR/IFR WITH RA/SN LIKELY. WINDS E 10-20 KT...BECOMING
N-NE.
THU...VFR. WINDS NE 10-15 KT.
FRI...MAINLY VFR. SLGT CHC MVFR CIGS WITH -RA/-SN. WINDS NE 5-10
KT.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WATCH FROM LATE TUESDAY NIGHT THROUGH THURSDAY
     MORNING FOR MNZ042>045-050-052-053.

WI...WINTER STORM WATCH FROM LATE TUESDAY NIGHT THROUGH THURSDAY
     MORNING FOR WIZ014>016.

&&

$$

SHORT TERM...JLT
LONG TERM...JPC
AVIATION...JLT






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