Area Forecast Discussion
Issued by NWS Sioux Falls, SD

Home | Current Version | Previous Version | Graphics & Text | 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 151742
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1142 AM CST MON DEC 15 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 542 AM CST MON DEC 15 2014

COMPLEX WINTRY SCENARIO WILL TAKE THE FOREFRONT TODAY...WITH AN
IMPRESSIVE TROUGH EARLY THIS MORNING MOVING SLOWLY THROUGH THE
CENTRAL PLAINS...AND IMPRESSIVE CONVEYOR OF MOISTURE FROM THE MID
MISSISSIPPI VALLEY BACK TOWARD NORTHERN NEBRASKA/SOUTHERN SOUTH
DAKOTA...WITH MOST LOCATIONS IN/NEAR THE TRAJECTORY AT LEAST 3SD
ABOVE NORMAL FOR PRECIPITABLE WATER. SOME CONCERN ABOUT THE IMPACTS
FROM WIDESPREAD CONVECTION WHICH PUSHED ACROSS THE CENTRAL PLAINS IN
TERMS OF MARGINALLY DISRUPTING THE INFLOW NORTH OF THE SYSTEM...BUT
REALLY PLENTY OF MOISTURE ALREADY IN PLACE. AT THE SURFACE..
BOUNDARY NEARLY STALLED AT 10Z FROM JUST SOUTHEAST OF KMJQ TO JUST
SOUTHEAST OF KSUX...WITH VERY HIGH MOISTURE AIR/FOG AT LOW LEVELS TO
THE EAST OF THIS BOUNDARY. TO THE WEST...COOLER AIR HAS SPILLED INTO
THE REGION...MAINLY LOWER 30S ACROSS SOUTHEAST SOUTH DAKOTA...LOWER
TO MID 30S IN SOUTHWEST MINNESOTA AND NORTHEAST NEBRASKA. STRONG PV
LOBE ROTATING AROUND UPPER LOW NORTHWARD THROUGH EASTERN NEBRASKA
WITH WIDESPREAD RAINFALL BREAKING OUT ON NOSE OF STRONG ADVECTION.
WITH MORE WIDESPREAD PRECIPITATION MOVING INTO SOUTHEAST SOUTH
DAKOTA...NORTHWEST IOWA AND SOUTHWEST MINNESOTA... TEMPS WILL LIKELY
STABILIZE FOR WHILE THIS MORNING AS PRECIP FALLS THROUGH THE WARM
LAYER BETWEEN 900-800 HPA. TO THE WEST...LESS OF AN IMPACT AS COOLER
AIR CONTINUES TO FILTER IN...SOMEWHAT MORE RAPIDLY NEAR SURFACE THAN
ALOFT FOR AT LEAST EARLY THIS MORNING.

RADAR ALREADY STARTING TO REVEAL WHERE BETTER AXIS FOR PRECIPITATION
WILL SET UP TODAY FROM SOUTH CENTRAL SD TOWARD SW MN...SOMEWHAT
LOWER THAN THE MID LEVEL FRONTAL BOUNDARY TO THE NORTHWEST OF THE
CWA. MORE WIDESPREAD PRECIPITATION EXPECTED THIS MORNING TO CONTINUE
TO FEED INTO THIS DEFORMATION AXIS WITHIN WEAK TROWAL STRUCTURE.
STILL HAVE A COUPLE OF MODELS WHICH INSIST ON MAX PRECIPITATION AXIS
WELL SOUTH OF KFSD...BUT THIS WOULD SEEM TO GO AGAINST WHERE EVEN
THE PARTICULAR MODEL SOLUTIONS ADVERTISE THE DRY SLOT WRAPPING NORTH
INTO NORTHWEST IOWA...BEFORE COLLAPSING SOUTHEAST LATE IN THE DAY...
AT WHICH TIME THE MORE BULK COOLING WILL ALSO SPEED PRECIPITATION
TRANSITION IN THE SOUTHEASTERN CWA. MIXED PRECIPITATION ACROSS THE
AREAS FROM THE JAMES VALLEY WESTWARD EARLY THIS MORNING WILL TRUDGE
GRADUALLY EASTWARD THROUGH THE DAY...REACHING THE KFSD AREA AROUND
NOON. SHOULD SEE SOME EARLIER TRANSITION TO LIGHT FREEZING RAIN TO
THE NORTH WHERE COLDER AIR AIDED BY LOWER SURFACE DEWPOINTS WORKS IN
EARLIER IN THE MORNING...AND WITH TEMPS ALOFT REMAINING WARM THROUGH
AT LEAST LATE MORNING...WILL HAVE A LONGER PERIOD OF ICING POTENTIAL
FROM EAST CENTRAL SD TOWARD NORTHERN SW MN. TO THE SOUTHEAST...
TRANSITION FROM RAIN TO SNOW...THROUGH FREEZING RAIN AND
SLEET...WILL PROBABLY BE SOMEWHAT BRIEFER OVER AN HOUR OR TWO PERIOD.

MADE A COUPLE OF CHANGES TO WINTER HIGHLIGHTS THIS MORNING. MAIN
ISSUE FOR EXPANDING WARNING INTO LAKE COUNTY DEALS WITH ICE
ACCUMULATION WHICH WAS IDENTICAL TO THOSE AREAS TO THE EAST...UP TO
A COUPLE TENTHS OF AN INCH. ALSO ADDED IN A WINTER WEATHER ADVISORY
TO BEADLE COUNTY EARLY THIS MORNING TO ACCOUNT FOR LIGHT ICING. DID
NOT CONTINUE PAST THE MID MORNING WITH SNOWFALL...AS AMOUNTS WILL BE
LESSER TO THE NORTHWEST OF THE MAIN BAND. OTHERWISE...HAVE NOT
ALTERED GEOGRAPHY OF HIGHLIGHTS.  WILL PROBABLY HAVE SOME DIFFICULTY
GETTING SNOW AMOUNTS UP TO WARNING CRITERIA ACROSS THE SOUTH
CENTRAL...BUT 4 TO 6 INCHES STILL A DISTINCT THREAT THROUGH LOWER
BRULE AREAS WITH A QUICKER TRANSITION TO SNOW EARLY THIS MORNING.
DID EXTEND THE EASTERN GROUPS TO MID EVENING...TO CAPTURE SOME
LOCATIONS WHERE ADDITIONAL SNOWFALL WILL BE UP TO AN INCH IN THE
EARLY EVENING.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 542 AM CST MON DEC 15 2014

DRY AND COOLER CONDITIONS EXPECTED TO DOMINATE ACROSS THE REGION
THROUGH THE REMAINDER OF THE WEEK AND INTO NEXT WEEKEND. CURRENT
STORM SYSTEM WILL SLOWLY LIFT NORTHEAST THROUGH THE LOWER GREAT
LAKES WITH ANOTHER LOBE OF ENERGY DROPPING INTO THE BACK SIDE ACROSS
THE WESTERN GREAT LAKES TUESDAY THROUGH WEDNESDAY. THIS WILL SERVE
TO REINFORCE THE COOLING ACROSS OUR AREA MIDWEEK...WITH TEMPERATURES
THEN EXPECTED TO RECOVER SLIGHTLY BUT STILL BE NEAR NORMAL BY THIS
COMING WEEKEND. PRECIPITATION CHANCES THROUGH THE PERIOD WILL BE LOW
AS PRIMARY SUPPORT WILL REMAIN WITH SOUTHERN JET STREAM ACROSS THE
SOUTHERN PLAINS/SOUTHEAST US...AS WELL AS ANOTHER TROUGH MOVING ON
TO THE WEST COAST LATE IN THE WEEK. MODELS STILL DIFFER A LITTLE ON
EXTENT TO WHICH PRECIP FROM SOUTHERN STREAM COULD EXPAND NORTHWARD
TOWARD OUR AREA LATE THIS WEEK...WITH GFS NOW THE ODD RUN OUT IN
SPREADING SOME LIGHT QPF INTO OUR FORECAST AREA ON FRIDAY. HOWEVER
GENERAL CONSENSUS IS TO KEEP PRECIP SOUTH OF THE AREA SO WILL
MAINTAIN DRY FORECAST.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1141 AM CST MON DEC 15 2014

MAIN CONCERN IS PRECIPITATION TYPE FOR THE NEAR TEAM AND THEN
CLOUDS AFTER 06Z. PRECIPITATION HAS CHANGES TO SNOW NORTH AND
WEST OF SIOUX FALLS. WITH TEMPERATURES NEAR FREEZING IN SIUOX
FALLS...EXPECT FREEZING RAIN AND SLEET THROUGH 19Z WITH A CHANGE
TO SNOW THEREAFTER. THERE WILL BE IFR VSBYS WITH SNOW THROUGH 03Z.
FOR KSUX...EXPECT SHOWERS MUCH OF THE AFTERNOON. COLDER AIR
EXPECTED TO MOVE IN AFTER 21Z WITH PRECIPITATION CHANGING DIRECTLY
TO SNOW. SNOWFALL WILL REDUCE VSBYS TO 2 TO 3 THIS EVENING. KHON
WILL SEE SNOW THROUGH 22Z. AFTER SNOW ENDS...LOW CLOUDS FROM 1000
TO 2000 FT EXPECTED THROUGH 18Z TUESDAY.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR SDZ061-
     062-066-067-069.

     WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR SDZ040-055-
     056.

     WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR SDZ038-
     039-052>054-057>060-064-065-068.

     WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR SDZ050-063.

MN...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR MNZ081-
     089-098.

     WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR MNZ071-072-
     080-097.

IA...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR IAZ001.

NE...NONE.
&&

$$

SHORT TERM...CHAPMAN
LONG TERM...JH
AVIATION...SCHUMACHER



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