Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 221845
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1245 PM CST SAT NOV 22 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM CST SAT NOV 22 2014

WARM AIR ADVECTION REGIME IS THE MAIN STORY OF THE SHORT TERM
PERIOD. BRISK SOUTHERLY WINDS HAVE ALLOWED TEMPERATURES TO CLIMB
ABOVE FREEZING /FOR THE FIRST TIME IN NEARLY TWO WEEKS/ OVERNIGHT
ACROSS SOUTHERN MN AND WESTERN WI. SURFACE DEW POINTS IN THE LOW
TO MID 30S CONTINUE TO PUSH NORTHWARD THROUGH IOWA AND WILL
CONTINUE FILLING IN ACROSS EASTERN MN AND WESTERN WI. WENT WITH A
PESSIMISTIC CLOUD/FOG FORECAST COMPARED TO MUCH OF THE GUIDANCE
WITH THE RELATIVE WARM AND MOIST AIR STREAMING NORTHWARD OVER THE
CURRENT SNOW PACK. DEW POINTS ACROSS WESTERN MN WILL LIKELY REMAIN
BELOW FREEZING THROUGH THE DAY AS THE BEST MOISTURE ADVECTION
STREAMING NORTHWARD TAKES AN EASTWARD TURN. MUCH OF SOUTHEASTERN
MN AND WESTERN WI ARE CURRENTLY SOCKED IN WITH LOW STRATUS AND
FOG...BUT MOSTLY CLEAR SKIES CAN BE FOUND TO THE WEST. THE HRRR
HAS PERFORMED WELL WITH THE COVERAGE OF THE CLOUDS/FOG...SO
WEIGHTED HEAVILY WITH THE HRRR IN THE SHORT RANGE FORECAST. THE
STRATUS DECK IS EXPECTED TO EXPAND SOME TO THE WEST THROUGH THE
MORNING...AND KEEP EASTERN MN AND WESTERN WI SOCKED IN THROUGH THE
DAY.

A COMPLICATED EVOLUTION OF THE FORECAST FOR TONIGHT THROUGH EARLY
SUNDAY MORNING.  A NORTHERN STREAM SHORTWAVE WILL MOVE ACROSS
SOUTHERN CANADA TODAY AND MAKE IT TO MANITOBA TONIGHT.
MEANWHILE...THE SOUTHERN STREAM WAVE WILL BE PIVOTING OVER THE
SOUTHERN CONUS.  THE BEST AREA OF LIFT WILL LARGELY REMAIN SOUTH OF
OUR AREA TONIGHT...BUT SOME MARGINAL LIFT ARRIVES TONIGHT AND WITH
SATURATED LOW LEVELS...DRIZZLE/LIGHT RAIN WILL BE POSSIBLE ACROSS
EASTERN MN AND WESTERN WI.  WITH MODEL SOUNDINGS ALSO INDICATING A
VERY SATURATED NEAR SURFACE ENVIRONMENT...EXPANDED MENTION OF FOG IN
THE FORECAST...ESPECIALLY FOR WESTERN WI.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 440 AM CST SAT NOV 22 2014

A MILD START TO THE LONG TERM PERIOD PRIOR TO THE MERGING OF
NORTHERN AND SOUTHERN STREAM WAVES...AND THEN ANOTHER SURGE OF
ARCTIC AIR BLASTS THE REGION.

00Z MODEL SOLUTIONS WERE FAIRLY SIMILAR IN THEIR DEPICTION OF POPS
FOR SUNDAY...WITH THE FORECAST AREA BEING SOMEWHAT CAUGHT BETWEEN
THE TWO MAIN AREAS OF FORCING ASSOCIATED WITH THE AFOREMENTIONED
WAVES. THIS WILL MEAN SUNDAY WILL BE A FOGGY DAY WITH OVERCAST
SKIES...BUT THE BULK OF THE MEASURABLE PRECIP WILL REMAIN OUTSIDE
OF THE AREA ON SUNDAY. THE EXCEPTION WILL BE THE EASTERN FORECAST
AREA TOWARD EAU CLAIRE...WHICH WILL BE ON THE WESTERN EDGE OF THE
H85 MOISTURE TRANSPORT.

ON SUNDAY NIGHT...COLDER AIR BEGINS TO INFILTRATE THE AREA AS THE
PARENT SURFACE LOW LIFTS TO LAKE SUPERIOR. THE TWO PRIMARY
CONCERNS AS THIS OCCURS WILL BE VERY STRONG WINDS AND SNOW/BLOWING
SNOW. THE HIGHEST WINDS ARE FORECAST IN THE TYPICAL WEST/SOUTH
CENTRAL MN AREAS...WHERE MODELS INDICATE 40-45KTS AT THE TOP OF
THE CHANNEL. THE STRONGER FORCING FOR SNOW IS FORECAST TO BE A BIT
REMOVED FROM THE STRONGER WINDS /NORTHERN MN/WI/...SO IT REMAINS
TO BE SEEN HOW SIGNIFICANT VISIBILITY REDUCTIONS WILL BE GIVEN THE
SNOWPACK WILL HAVE ENDURED MELTING/RE-FREEZING/DRIZZLE.

WINDS SETTLE DOWN ON TUESDAY...THEN 850 MB TEMPS REDUCE TO AROUND
-15C LATE WEDNESDAY. ANOTHER WEAK WAVE CLIPS THE AREA ON
WEDNESDAY...BRINGING 20-30 PERCENT SNOW CHANCES. THESE VALUES
ARE AROUND 2 STANDARD DEVIATIONS BELOW NORMAL...AND TRANSLATE TO A
CHILLY THANKSGIVING DAY WITH HIGHS IN THE UPPER SINGLE DIGITS TO
MID TEENS. TEMPS REBOUND NICELY ON FRIDAY HOWEVER...WHEN HIGHS ARE
EXPECTED TO WARM INTO THE LOW/MID 20S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1148 AM CST SAT NOV 22 2014

IFR AND LOWER STRATUS CONTINUES TO SLOWLY CRAWL NW ACROSS
MN...STILL QUESTIONABLE WHETHER OR NOT IT REACHES AXN...BUT WITH
12Z TAF HAVING IT GETTING THERE...KEPT THAT TREND GOING. THESE
CIGS WILL ONLY MARGINALLY IMPROVE THROUGH THE AFTERNOON...LIKELY
JUST GOING FROM LIFR TO IFR BEFORE GOING BACK TO LIFR TONIGHT.
GIVEN CONTINUED SOUTH WINDS AND INCREASING MOISTURE OVER THE SNOW
THROUGH THE NIGHT...KEPT THE TREND FOR FG TONIGHT FROM 12Z TAFS
GOING. UNCERTAINTY STARTS TO INCREASE TOMORROW WITH THE POTENTIAL
FOR CIGS TO QUICKLY GO VFR. FOR NOW...TIMED IMPROVEMENT IN CIGS TO
WHEN WINDS ARE FORECAST TO SWING AROUND TO 240 DEGS OR GREATER.
SREF MVFR CIG PROBABILITY DROPS TO NEAR ZERO SUNDAY MORNING OUT
WEST...SO WE COULD VERY WELL SEE CIGS IMPROVE FASTER THAN
CURRENTLY INDICATED ACROSS MN. FOR PRECIP...LOOKING LIKE OUR BEST
CHANCE THIS TAF PERIOD WILL BE WITH A NARROW BAND OF RAIN THE
NMM/ARW/GFS/SREF SHOW COMING OUT OF SODAK LATE TONIGHT AND WORKING
ACROSS MN DURING THE MORNING.

KMSP...CONFIDENCE IS HIGH IN MINIMAL IMPROVEMENTS TO CIGS/VIS
THROUGH THE DAY. CONTINUED MOIST SRLY FLOW WILL ALSO LEAD TO A
LOWERING IN CONDITIONS TONIGHT...THOUGH THERE IS LESS CONFIDENCE
IN THE TIMING ON WHEN CIGS DROP BACK BELOW 005. 50/50 CONFIDENCE
ON THE FOG TEMPO GROUP...BUT WITH IT ALREADY IN THE TAF...LEFT IT
THERE. CONFIDENCE IS CONSIDERABLY LOWER THIS FAR OUT WITH
IMPROVEMENTS IN THE TAF BY SUNDAY AFTERNOON...BUT FOLLOWED THE
IDEA OF THE NAM/SREF ON THAT FOR NOW.

/OUTLOOK FOR KMSP/
MON...MVFR/IFR CIGS CHC -SN. WINDS NW 20G30 KT.
TUE...VFR. WINDS W 5-10 KT.
WED...MVFR/IFR CHC -SN. WINDS NW 10KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...SPD
LONG TERM...LS
AVIATION...MPG





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