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000
FXUS63 KFSD 070440
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1040 PM CST THU MAR 6 2014

.UPDATE...
ISSUED AT 912 PM CST THU MAR 6 2014

NOT PLANNING ANY MAJOR CHANGES TO THE GOING FORECAST. STILL
THINKING JUST A LIGHT ICING POTENTIAL. THE ONLY AREA THAT MAY
PROVE TO GET A COUPLE OF HUNDREDTHS IS ALONG HIGHWAY 14 LATER
TONIGHT BUT EVEN THAT IS UP IN THE AIR AS MODEL AGREEMENT JUST IS
NOT THERE. ENOUGH DRY AIR ALOFT TO REALLY QUESTION HOW MUCH LIQUID
PRECIPITATION CAN DEVELOP AND REACH THE GROUND. AS SEEN WITH SOME
OF THE ECHOES IN CENTRAL SD PIR IS ONLY SCATTERED AT 12000 FEET SO
PRETTY DRY BELOW THE DEVELOPING ECHOES. THE OTHER CONCERN WILL BE
FREEZING DRIZZLE/FREEZING FOG WITH SOME LOW LEVEL MOISTURE THAT IS
TRAPPED BELOW THE INVERSION. ALONG AND EAST OF INTERSTATE 29 HAS
SEEN SOME 4 TO 6 MILE VISIBILITIES IN LIGHT FOG BUT THIS NOT
LIKELY ENOUGH TO PRODUCE WIDESPREAD VERY SLIPPERY CONDITIONS.
SO...WILL NEED TO WATCH THE LIFT THAT IS MOVING IN FROM NORTHWEST SD
INTO SOUTH CENTRAL ND TO SEE IF THAT CAN SATURATE TO THE SURFACE.
IF IT CAN THEN THE HIGHWAY 14 CORRIDOR MIGHT HAVE SOME MEASURABLE
FREEZING PRECIPITATION. NO PLANS TO ISSUE AN ADVISORY AT THIS TIME
BUT FOLKS SHOULD BE PREPARED FOR A FEW SLICK SPOTS IN THE
MORNING...ESPECIALLY UNTREATED ROADS...SIDEWALKS AND DRIVEWAYS.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 342 PM CST THU MAR 6 2014

BLOWING/DRIFTING SNOW HAS BECOME A PROBLEM ACROSS NORTHEAST PARTS OF
THE AREA THIS AFTERNOON...DUE TO GUSTY SOUTH WINDS IN AREAS WHICH
HAD RECEIVED GREATEST SNOWFALL EARLIER THIS WEEK. VISIBILITY DOWN TO
A MILE OR LESS AT TIMES...BUT DID NOT APPEAR WIDESPREAD NOR FREQUENT
ENOUGH TO WARRANT WINTER WEATHER ADVISORY. GREATER TRAVEL ISSUES DUE
TO DRIFTING SNOW MELTING ON WARMING ROAD SURFACES...THEN REFREEZING
AS ADDITIONAL SNOW DRIFTS ACROSS THE ROADS. ISSUED SPECIAL WEATHER
STATEMENT TO COVER THE ICY ROAD CONDITIONS...AND POSTED INFORMATION
ON OUR SOCIAL MEDIA/HOMEPAGE. WINDS EXPECTED TO EASE SOME BY LATE
AFTERNOON/EVENING...BUT ICY ROAD CONDITIONS LIKELY TO CONTINUE.

MAIN WEATHER CONCERN OVERNIGHT/FRIDAY TURNS TO POTENTIAL FOR LIGHT
MIXED PRECIP WITH COLD FRONT/WEAK MID LEVEL WAVE MOVING ACROSS THE
REGION. HAVE FINALLY SCOURED OUT A GOOD PORTION OF THE WIDESPREAD
STRATUS DECK...BUT STILL REMNANTS AROUND...ALONG WITH LIGHT FOG WITH
2-4SM VISIBILITY. THIS MOISTURE WILL ONLY BE TRAPPED AS WEAK WARM
ADVECTION ALOFT CONTINUES AHEAD OF THE FRONT THIS EVENING...AND THUS
EXPECTING STRATUS/FOG TO REDEVELOP IN CENTRAL/EASTERN PORTIONS OF
THE CWA BY LATE EVENING. ALL MODELS SHOWING PRETTY DEEP DRY LAYER
BETWEEN THIS NEAR SURFACE MOISTURE AND MID CLOUDS ADVANCING IN WITH
THE UPPER WAVE...THUS DO NOT THINK MEASURABLE PRECIP CHANCE IS THAT
GREAT OVERNIGHT...AND HAVE REMOVED POPS AS A RESULT. HOWEVER...WITH
INCREASING LIFT JUST ABOVE THE EXPECTED DEVELOPING STRATUS LAYER...
THINK DRIZZLE IS A POSSIBILITY...AND AREAS OF FREEZING DRIZZLE ARE
UNFORTUNATELY ALSO POSSIBLE AS TEMPERATURES HOVER RIGHT AROUND 32F.
HAVE ADDED MENTION OF THIS TO AREAS AHEAD OF THE BOUNDARY...MAINLY
06Z-14Z TIME FRAME...DIMINISHING FROM WEST TO EAST THROUGH THE EARLY
MORNING AS THE FRONT MOVES IN.

LATER MORNING/AFTERNOON WE SEE A LITTLE DEEPER MOISTURE STREAM INTO
SOUTHERN PARTS OF THE AREA...AND WILL MAINTAIN CHANCE POPS SOUTH OF
I-90. ANY PRECIP AMOUNTS EXPECTED TO BE ON THE LIGHT SIDE...LESS
THAN 0.05 INCH. PROBLEM IS THAT WARM LAYER ALOFT COULD LEAD TO A MIX
OF PRECIP TYPES. MOST LIKELY RAIN OR A LITTLE SLEET TO START...WITH
TEMPERATURES THROUGH EARLY AFTERNOON EXPECTED TO STILL BE ABOVE
FREEZING IN OUR FAR SOUTHERN AREAS DUE TO WARM AND MOIST SOUTHERLY
FLOW. COULD CHANGE TO A LITTLE LIGHT SNOW AS TEMPERATURES CONTINUE
TO COOL BEHIND THE BOUNDARY/WAVE...BUT DO NOT EXPECT MUCH SNOW
ACCUMULATION DUE TO RELATIVELY SHORT DURATION BEFORE PRECIP BEGINS
TO WIND DOWN. AS FOR TEMPERATURES...HIGHS WILL LIKELY BE SEEN IN THE
MORNING...BELOW FREEZING ALONG AND NORTH OF I-90 WITH READINGS JUST
ABOVE FREEZING TO THE SOUTH. SLIGHT COOLING INTO THE MID-UPPER 20S
FOR MOST THROUGH THE AFTERNOON...ALTHOUGH COOLING CURRENTLY DOES NOT
LOOK QUITE AS SHARP AS EARLIER THOUGHTS...WHICH WILL ALSO MINIMIZE
POTENTIAL FOR ANY FREEZING RAIN.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 342 PM CST THU MAR 6 2014

THE FRONTAL BOUNDARY WILL BE WELL TO OUR SOUTH BY FRIDAY
EVENING...AND ANY LINGERING PRECIPITATION WILL BE IN THE FORM OF
SNOW IN OUR FAR SOUTHEAST...WITH ONLY A TENTH OR TWO OF ADDITIONAL
ACCUMULATION. OTHERWISE...WILL HAVE GENERALLY DECREASING CLOUDS
THROUGH THE NIGHT...AND WITH THE BULK OF THE COLDEST AIRMASS
SETTLING INTO THE REGION TEMPERATURES WILL DROP INTO THE LOWER TEENS
THROUGH THE MISSOURI RIVER VALLEY TO MAINLY SINGLE DIGITS ELSEWHERE
ACROSS THE AREA.

HIGH PRESSURE WILL SETTLE INTO THE REGION ON SATURDAY...AND IN AN
EVOLVING SOUTHWESTERLY FLOW BEHIND THE EXITING HIGH PRESSURE
TEMPERATURES WILL BEGIN TO MODERATE IN OUR WEST BY SATURDAY
AFTERNOON. THIS WILL BE REALIZED WITH TEMPERATURES CLIMBING INTO THE
LOWER 40S IN OUR SOUTH CENTRAL SOUTH DAKOTA ZONES...WHILE BACK TO
THE EAST WHERE THERMAL PROFILES ARE COOLER HIGHS WILL REMAIN IN THE
20S. WITH WARM AIR ADVECTION STRENGTHENING ON SATURDAY NIGHT AND
SOUTHERLY WINDS PICKING UP A BIT IN A TIGHTENING GRADIENT...IT WILL
BE A MILDER NIGHT WITH LOWS GENERALLY RANGING FROM THE 20S WEST OF
INTERSTATE 29 TO THE TEENS TO THE EAST.

THE MORE NOTICEABLE WARMING WILL BEGIN ON SUNDAY AND MONDAY AS UPPER
LEVEL RIDGING BUILDS INTO THE REGION AND 925 MB TEMPERATURES
MODERATE INTO THE 10 TO 15 DEGREES C RANGE. READINGS WILL BE
SOMEWHAT DEPENDENT ON THE AMOUNT OF SNOWCOVER IN PLACE BY THAT
POINT...BUT APPEARS THAT HIGHS WILL CLOSE IN ON 60 DEGREES THROUGH
THE MISSOURI RIVER CORRIDOR ON THOSE DAYS...BUT REMAINING IN THE 40S
AROUND AND EAST OF A LINE RUNNING ROUGHLY FROM BROOKINGS TO SPENCER
WHERE SNOW COVER IS DEEPER.

MODELS IN PRETTY DECENT AGREEMENT ON A SHORTWAVE TRACKING THROUGH
THE REGION SOMETIME IN THE TUESDAY TIME FRAME...BRINGING A CHANCE OF
PRECIPITATION TO THE AREA ON MONDAY NIGHT AND TUESDAY. USED A
RAIN/SNOW PRECIP TYPE AT THIS POINT DEPENDENT ON SURFACE
TEMPERATURES...THOUGH CANNOT RULE OUT SOME OTHER TYPE OF MIXED
PRECIPITATION ON MONDAY NIGHT BEFORE TEMPERATURES COOL ALOFT. THIS
WAVE WILL BRING IN COOLER TEMPERATURES FOR TUESDAY AND
WEDNESDAY...THOUGH REMAINING ABOVE NORMAL FOR THIS TIME OF YEAR.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1034 PM CST THU MAR 6 2014

LIGHT ICING STILL THE MAIN CONCERN OVER THE NEXT 12 HOURS OR SO.
EXPECT IFR CONDITIONS TO DEVELOP AFTER ABOUT 9Z THEN SHIFT EAST AS
THE FRONT MOVES THROUGH...WITH CONDITIONS LIKELY RISING BUT STAYING
WITHIN MVFR FOR MOST OF THE REMAINDER OF TH PERIOD. A BAND OF
PRECIPITATION OVER NORTHWEST SOUTH DAKOTA WILL LIKELY WEAKEN A BIT
AS IT SHIFTS EAST AND STRUGGLE AGAINST SOME LOW LEVEL DRY AIR.
WILL NEED TO WATCH THE HIGHWAY 14 CORRIDOR OVERNIGHT AS THAT
SHOULD BE THE HIGHEST THREAT FOR MEASURABLE LIGHT FREEZING
PRECIPITATION. FARTHER SOUTH TOWARDS INTERSTATE 90 LOW LEVEL
SATURATION AND LIGHT FREEZING DRIZZLE SHOULD BE THE MAIN THREATS
FROM ABOUT 9Z THROUGH 15Z. ADDITIONAL FORCING SHOULD ORGANIZE LATE
THIS MORNING INTO THE AFTERNOON OVER NORTHEAST NEBRASKA INTO
NORTHWEST IOWA AND SOME RAIN OR SNOW WILL BE POSSIBLE. SOUNDING
ALSO MARGINALLY SUPPORTIVE OF A LITTLE SLEET WITH SOME INSTABILITY
ABOVE 700MB SO THAT POTENTIAL WILL NEED TO BE WATCHED AS WELL.

&&

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

$$

UPDATE...08
SHORT TERM...JH
LONG TERM...JM
AVIATION...08