Area Forecast Discussion
Issued by NWS Sioux Falls, SD

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KFSD 280916
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
316 AM CST FRI NOV 28 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 311 AM CST FRI NOV 28 2014

ANOTHER WEAK WAVE AND PUSH OF WARM AIR ADVECTION WILL MOVE ACROSS
THE AREA TODAY LEADING TO INCREASING MID LEVEL CLOUDINESS. HOWEVER
THE LOW LEVEL DRYING ASSOCIATED WITH THIS WARM LAYER WILL PROBABLY
PREVENT ANY PRECIPITATION FROM REACHING THE GROUND. BETTER LOW LEVEL
SATURATION IS SEEN NORTH OF THE CWA...WHERE THE BEST CHANCE OF SOME
LIGHT PRECIP EXISTS. SOME OF THE HI RES MODEL SOLUTIONS SCRAPE OUR
FAR NORTHEAST...NEAR MARSHALL...WITH LIGHT PRECIP FROM MID TO LATE
MORNING. HOWEVER AT THIS TIME STILL THINKING THE DRY AIR WILL WIN
OUT KEEPING OUR AREA PRECIP FREE. WILL NEED TO MONITOR THOUGH...AS
GIVEN THE WARM LAYER ADVECTING IN...ANY THING THAT DID FALL WOULD
LIKELY BE IN THE FORM OF LIGHT FREEZING RAIN.

MODEL SOLUTIONS SUGGEST THE AREA OF MID LEVEL CLOUDINESS MAY EXIT
TO THE EAST THIS AFTERNOON...ALLOWING FOR PARTLY TO POSSIBLY MOSTLY
SUNNY SKIES TO TAKE OVER. WEAK MIXING WILL NOT ALLOW US TO FULLY
REALIZE THE WARMING ALOFT...HOWEVER WITH ONLY LIMITED SNOWPACK...AND
THE SUN AND WARMING TEMPERATURES HELPING TO MELT THAT...THINK IT
WILL STILL END UP BEING A RELATIVELY MILD DAY. RELIED ON THE ECMWF
AND GEM FOR TEMPERATURES...AS BOTH THE NAM AND GFS DO A POOR JOB
HANDLING THE BOUNDARY LAYER EVOLUTION WHEN WE HAVE SNOW COVER AND
DISSIPATING SNOW COVER. THIS RESULTS IN 30S OVER SOUTHWEST MINNESOTA
TO THE MID AND UPPER 40S ALONG THE MISSOURI RIVER
CORRIDOR...PROBABLY EVEN LOW 50S SOUTH CENTRAL SOUTH DAKOTA.

FORECAST CONCERN TONIGHT IS POSSIBLE DENSE FOG AND OR LOW STRATUS
FORMATION. LOW LEVEL MOISTURE ADVECTION COMBINED WITH THE MELTING
SNOW WILL LIKELY LEAD TO QUITE A BIT OF MOISTURE BUILD UP UNDERNEATH
TODAYS INVERSION. CLEAR SKIES AND RELATIVELY LIGHT WINDS SHOULD
ALLOW FOR A QUICK DROP IN TEMPERATURES THIS EVENING INTO THE UPPER
TEENS AND 20S...WHICH MAY ALLOW FOR THE AFOREMENTIONED FOG OR
STRATUS TO DEVELOP. BEST CHANCE WOULD BE EAST OF THE JAMES
RIVER...AND A WIND SHIFT BRINGING IN DRIER AIR...WILL LIKELY ALLOW
FOR AN EROSION OF ANY FOG FROM WEST TO EAST BY LATER TONIGHT. DUE TO
THE EARLIER MENTIONED ISSUES WITH THE NAM AND GFS BOUNDARY
LAYER...TOUGH TO REALLY ASCERTAIN THE DEGREE OF THE FOG THREAT. BUT
THE PATTERN SUGGESTS FOG IS DEFINITELY A POSSIBILITY...AND EVEN THE
ECMWF AND GEM SURFACE HUMIDITY SHOWS SIGNS OF THE POTENTIAL. SO
WHILE CONFIDENCE IS NOT GREAT...IT IS HIGH ENOUGH TO CONTINUE
MENTION IN THE FORECAST.


.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 311 AM CST FRI NOV 28 2014

ONLY MINOR CHANGES MADE TO THE MEDIUM AND EXTENDED RANGE
FORECAST...AS A MOSTLY DRY STRETCH OF WEATHER CONTINUES. PRIMARY
CONCERNS ON SATURDAY CONTINUE TO REVOLVE AROUND TEMPERATURES.
DEPENDING ON THE AMOUNT OF FOG/STRATUS IN THE AREA...SHOULD BE A
RELATIVELY QUICK WARMUP ON SATURDAY. AGAIN...STAYED WITH THE WARMEST
GUIDANCE OF THE ECMWF WITH TOO MUCH INFLUENCE FROM SNOW COVER IN
OTHER RAW GUIDANCE.

COLD FRONT WILL BLAST THROUGH THE AREA OVERNIGHT INTO SUNDAY.
STRONGEST WINDS WILL LINGER BEHIND THE INITIAL FRONT...AND
SUSTAINED WINDS MAY PUSH 15 TO 20 KNOTS. SOUNDINGS SUGGEST
SHALLOW LOW-LVL MOISTURE AS THE FRONT MOVES THROUGH...WITH COOLING
THERMO PROFILE INDICATING THE POTENTIAL FOR FLURRIES THROUGH
SUNDAY MORNING.

SUNDAY AND SUNDAY NIGHT WILL BE BITTERLY COLD...WITH TEMPERATURES
CONTINUING TO FALL INTO MID-MORNING. WIND CHILLS OVER THE NORTHERN
ZONES MAY APPROACH -20 BY SUNDAY EVENING INTO MONDAY MORNING.
ABSENT SNOW COVER...EXTREME COLD IS NOT LIKELY...BUT SEVERAL AREAS
SHOULD FALL BELOW ZERO BY DAYBREAK MONDAY.

WINDS WILL QUICKLY TURN SOUTHERLY AHEAD OF AN UPPER TROUGH RACING
THROUGH THE NORTHERN PLAINS. SOUTHWEST WINDS MONDAY NIGHT WOULD
PROMOTE A NON-DIURNAL TEMPERATURE CURVE INTO TUESDAY MORNING. THE
PROGRESSIVE NATURE OF THE FLOW ALOFT WILL PREVENT TEMPERATURES FROM
CLIMBING TOO HIGH ON TUESDAY...AS YET ANOTHER WEAK COLD FRONT
PUSHES THROUGH INTO WEDNESDAY.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1057 PM CST THU NOV 27 2014

BAND OF MID AND HIGH CLOUDS CONTINUES TO STREAM ACROSS THE
FORECAST AREA BUT WILL SHIFT EAST AND BECOME SCATTERED THROUGH THE
EARLY MORNING HOURS. A FEW REMAINING FLURRIES NEAR THE BUFFALO
RIDGE SHOULD ALSO END WITHIN THE NEXT FEW HOURS. VFR CONDITIONS
ARE EXPECTED THROUGH THE TAF PERIOD.


&&

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

$$

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.