686 
FXUS63 KFSD 041112
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
512 AM CST TUE NOV 4 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CST TUE NOV 4 2014

BREEZY NORTHWEST FLOW IS EXPECTED TO PREVAIL THROUGHOUT THE DAY 
TODAY IN THE WAKE OF A COLD FROM THAT MOVED THROUGH THE AREA TODAY.  
WITH RELATIVELY DRY ATMOSPHERE AND UNIDIRECTIONAL FLOW...EXPECT A 
FAIRLY MIXY DAY AND HAVE SIDED CLOSER TOWARD THE WARM SIDE OF 
GUIDANCE.  MODELS SHOW A DRY LAYER FROM 900-800 MB MOVING INTO THE 
FORECAST AREA THIS AFTERNOON.  WITH GOOD MIXING CONDITIONS...EXPECT 
DEW POINTS TO FALL INTO THE MID AND UPPER 20S LEADING TO RH VALUES 
OF 30-35 PERCENT.  WITH NORTHWEST WINDS OF 15 -30MPH...SHOULD BE 
ANOTHER ELEVATED FIRE WEATHER DAY.  

WINDS SHOULD DECREASE THIS EVENING AS MIXING SUBSIDES AND MOMENTUM 
ALOFT BECOMES DISCONNECTED FROM THE SURFACE.  EXPECT CLOUDS TO 
INCREASE TOWARD 06Z TIMEFRAME AS SHORTWAVE APPROACHES FROM THE 
NORTHWEST.  WAVE IS STILL MOISTURE STARVED AND WORKS TOWARDS THE 
EAST CENTRAL PORTIONS OF SOUTH DAKOTA AROUND 12Z.  THE CANADIAN IS A 
LITTLE QUICKER AND FURTHER EAST THAN THE OTHER SOLUTIONS...BUT GIVEN 
IT IS THE OUTLIER...DISCOUNTED ITS SOLUTION FOR NOW.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 333 AM CST TUE NOV 4 2014

ONLY MINOR CHANGES NEEDED TO THE MEDIUM AND EXTENDED RANGE 
FORECASTS. MODELS CONTINUE TO INDICATE TWO CLIPPER SYSTEMS MOVING 
THROUGH THE REGION THIS WEEK...WITH INCREASING POTENTIAL FOR AN 
INTRUSION OF COLDER AIR EARLY NEXT WEEK.

WEDNESDAY...SLIGHT TRACK DIFFERENCES IN GUIDANCE BETWEEN THE 
NAM/GFS/ECMWF REGARDING CLIPPER-LIKE SYSTEM MOVING THROUGH THE 
REGION.  NAM HAS TRENDED FURTHER NORTH...WITH GFS/EC SLIGHTLY 
FURTHER SOUTH AND MORE SIMILAR IN THEIR SOLUTIONS. THAT SAID...STILL 
ANTICIPATING A QUICK WARMUP BEFORE COLDER AIR SURGES SOUTHWARD LATE 
WEDNESDAY AFTN. LIGHT PRECIP MAY BREAK OUT AS THIS WAVE MOVES INTO 
THE REGION EARLY ON WEDNESDAY...BUT SLIGHTLY HIGHER CHANCES WILL 
ARRIVE IN THE AFTERNOON AS EXIT REGION OF UPPER JET PIVOTS INTO THE 
AREA. PRECIP TYPE CONTINUES TO FAVOR THE LIQUID VARIETY GIVEN WARM 
LOW-LVLS. SOUNDINGS CONTINUE TO FAVOR STRONG WINDS ON THE BACKSIDE 
OF THIS SYSTEM WEDNESDAY AFTERNOON...ESPECIALLY WEST OF THE JAMES 
RIVER WHERE ADVISORY LVLS MAY BE POSSIBLE. WINDS WILL RELAX INTO THE 
OVERNIGHT HOURS AS HIGH PRESSURE MOVES EASTWARD.

A COOL DAY IS EXPECTED ON THURSDAY AS THE SURFACE HIGH MOVES ACROSS 
THE AREA. LIGHT SURFACE WINDS AND THE LOW-LVL RIDGE AXIS OVERHEAD 
WILL LIMIT THE DEPTH OF MIXING...AND KEEP TEMPERATURES SLIGHTLY 
BELOW NORMAL.

THE NEXT MORE DISORGANIZED SYSTEM WILL MOVE THROUGH THE AREA FRIDAY 
AND FRIDAY NIGHT. SOUNDINGS SHOW LIMITED MOISTURE AS THIS WAVE 
PIVOTS THROUGH THE AREA...WITH MUCH OF THE MOISTURE AOA 10K FT AGL. 
WILL MAINTAIN SLIGHT CHC POPS GIVEN MID-LVL FRONTOGENESIS BAND 
MOVING THROUGH...BUT QPF SHOULD BE LIGHT. 

A QUIET WEEKEND IS IN STORE FOR THE AREA...WITH TWO BELOW NORMAL 
DAYS EXPECTED. THE COLDEST DAY WILL BE SATURDAY WITHIN THE COLD 
CANADIAN AIRMASS...BUT RETURN FLOW WILL DEVELOP SUNDAY BRINGING 
TEMPERATURES BACK INTO THE MID TO UPPER 40S.

GUIDANCE CONTINUES TO TREND TOWARDS A SOLN THAT WOULD PULL A LARGE 
POLAR LOW SOUTHWARD INTO HUDSON BAY EARLY NEXT WEEK. THIS SETUP 
WOULD FAVOR A SUBSTANCIAL INTRUSION OF COLD AIR INTO THE UNITED 
STATES TOWARDS MONDAY.  THE UNCERTAINTY IN THE LOCAL AREA IS WHETHER 
THIS WILL BE A SUBSTANCIAL INFLUENCE OF COLD AIR OR A GLANCING BLOW.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 500 AM CST TUE NOV 4 2014

VRF CONDITIONS EXPECTED THROUGH THE PERIOD. BREEZY NORTHWEST
CONDITIONS WILL DEVELOP BETWEEN 15-18Z THIS MORNING AND CONTINUE
THROUGH LATE AFTERNOON. THESE CONDITIONS WILL SUBSIDE WITH
SUNSET...AND CLOUDS WILL BE ON THE INCRASE FROM THE NORTH TUESDAY
NIGHT. 

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...
LONG TERM...DUX
AVIATION...