Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 170447
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1047 PM CST SUN NOV 16 2014

.UPDATE...
ISSUED AT 945 PM CST SUN NOV 16 2014

WENT AHEAD AND CANCELLED THE WINTER WEATHER ADVISORY FOR TONIGHT.
THAT SAID...DECIDED TO LEAVE IT LINGER FOR SOUTHWEST MN...AND
PARTS OF NORTHWEST IA DOWN THE FAVORED HIGHER TERRAIN AREAS FOR
THE LATE MORNING ON MONDAY AND MONDAY AFTERNOON. THIS IS WHEN THE
MIXING WINDS WILL HIT THOSE AREAS...AND IF WE CAN GET SOME GUSTS
AROUND 35 MPH OR A LITTLE HIGHER...THAT COULD CREATE SOME BLOWING
SNOW CONCERNS FOR THOSE LOCATIONS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 345 PM CST SUN NOV 16 2014

LARGE UPPER LEVEL POTENTIAL VORTICITY SWINGING THROUGH THE AREA
TODAY WHICH IS BRINGING A QUICK INCREASE TO NORTHWEST WINDS. PARTS
OF CENTRAL SOUTH DAKOTA HAVE SEEN GUSTS OF 40 TO 45 MPH...WHICH IS
CAUSING SOME BLOWING AND DRIFTING BUT SO FAR NO MAJOR VISIBILITY
REDUCTIONS IN MOST CASES. SOME SPOTTY INSTABILITY SNOW SHOWERS ALSO
CREEPING THROUGH NORTHEAST SOUTH DAKOTA...AND WILL REACH AREAS
MAINLY NORTH OF INTERSTATE 90. THESE SNOW SHOWERS...COUPLED WITH
BLOWING SNOW...WILL AT TIMES REDUCE THE VISIBILITY TO A HALF MILE.
MUCH OF THE SNOW SHOWER ACTIVITY LIKELY TO END BY ABOUT 2Z OR 3Z
THIS EVENING...BUT THE WINDS WILL CONTINUE THROUGH THE NIGHT. THERE
MAY BE A LULL IN THE WINDS IN PLACES FROM ABOUT 6Z THROUGH 12Z...BUT
WITH JUST A TOUCH OF MIXING ON MONDAY MORNING WINDS GUSTS WILL AGAIN
APPROACH 35 TO 40 MPH ON MONDAY MORNING AND AFTERNOON...ESPECIALLY
IN THE EASTERN CWA WHERE THE STRONGEST GRADIENT IS. ALONG WITH THE
STRONG WINDS AND REDUCED VISIBILITY WILL BE COLD TEMPERATURES.
EXPECTING OVERNIGHT LOWS OF MAINLY ZERO TO 5 ABOVE...BUT WHEN
COUPLED WITH THE WINDS THE WIND CHILL VALUES WILL CREEP DOWN TO
ABOUT 10 BELOW TO 20 BELOW ZERO FOR LATE TONIGHT AND MONDAY MORNING.
WITH SNOW ON THE GROUND AND A SURGE OF VERY COLD AIR TEMPERATURES
WILL REBOUND VERY LITTLE ON MONDAY...WITH HIGHS MAINLY 9 TO 14
ABOVE. AREAS OF BLOWING AND DRIFTING SNOW LIKELY TO CONTINUE THROUGH
MONDAY...ESPECIALLY ALONG AND EAST OF INTERSTATE 29...SO THE WINTER
WEATHER ADVISORY FOR BLOWING SNOW LOOKS GOOD FOR THE AREA. NO
CHANGES EXPECTED TO IT.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 345 PM CST SUN NOV 16 2014

WINDS WILL CONTINUE TO DROP OFF MONDAY EVENING WITH WEAK RIDGE
AXIS TO THE WEST SLIPPING INTO THE WESTERN HALF OF THE AREA.
AS FLOW TURNS TOWARD WEAK WARM AIR ADVECTION LATER IN THE NIGHT...
THIS SHOULD HELP TO DECOUPLE...AND ANY LOWER CLOUDS LIKELY TO
DWINDLE THROUGH THE NIGHT AND ONLY A FEW HIGHER CLOUDS VERY LATE
SHOULD LEAD TO MAXIMIZING THE DROP IN WINDS. WILL CONTINUE TO
SHADE TOWARD LOWER RANGES OF GUIDANCE. TEMPS WARM ALOFT QUITE A
BIT ON TUESDAY AHEAD OF NEXT WAVE/COM DROPPING SOUTHEAST...BUT
INCREASED STABILITY AND WITH INCREASING CLOUDS EXPECT WARMING WILL
BE SOMEWHAT LIMITED IN COMPARISON.

COLD FRONT CRASHES ACROSS THE AREA TUESDAY NIGHT. TEMPS WILL
PROBABLY MIX OUT SOMEWHAT FOR A WHILE BEFORE TAILING OFF LATE.
30 TO 35 KNOTS WIND AGAIN WITHIN THE MIXED LAYER...WITH TEMPS
AGAIN FALLING INTO THE RANGE LIKELY TO PRODUCE A FEW FLURRIES.
DO NOT EXPECT BLOWING SNOW TO BE MUCH OF AN ISSUE AFTER SHORTER
TERM COMPACTION AND PASSAGE OF SEVERAL DAYS. MOVING AHEAD...GFS
MORE AGGRESSIVE WITH COLD PUNCH INTO THE PLAINS WITH WAVE DIGGING
MORE WESTWARD INTO MINNESOTA...BUT SEEMS TO NOT BE AS SUPPORTED IN
THE ENSEMBLES...AS NEITHER DOES THE MUCH SLOWER AND STRONGER WAVE
IN THE CANADIAN GLOBAL. OVERALL...APPEARS CORE OF THE COLDER AIR
WILL SLIP DOWN ON THURSDAY AND SLOWLY PULL EASTWARD THURSDAY
NIGHT. THURSDAY NIGHT VERY SIMILAR TO TUESDAY NIGHT...BUT RIDGE
EVACUATING TO EAST RATHER THAN BUILDING IN. WINDOW FOR BETTER
COOLING SHOULD BE EARLIER IN THE NIGHT.

FINALLY SEE SIGNS OF SLIGHT MODERATION TO TEMPS...BUT STILL BELOW
NORMAL THROUGH THE PERIOD. SOUTHERLY FLOW INCREASES ON FRIDAY
THROUGH FRIDAY NIGHT...AS FLOW GOES ZONAL. SPLIT TROUGHING IN
MORE ZONAL FLOW DEVELOPS THIS WEEKEND...WITH ECMWF MUCH MORE
INTENSE WITH LEADING ENERGY THAN OTHER SOLUTIONS. MORE LIKELY TO
SEE WEAKER LEAD WAVE AND MORE HOLDING BACK WITH BETTER PV
RESERVOIR TO DRAW ON. WHILE HAVE NOT SETTLED IN ON MENTION OF
MUCH IN THE WAY OF PRECIPITATION CHANCES THROUGH SUNDAY...WILL
HAVE TO WATCH MORE POTENTIAL SHALLOW/NON MEASURABLE PRECIPITATION
PROCESSES DEVELOPING ON SATURDAY AND CONTINUE INTO SUNDAY AS
STRONGER WAVE MOVES INTO THE PLAINS. PRETTY INTERESTING POTENTIAL
AND WILL WARRANT WATCHING OVER THE NEXT SEVERAL DAYS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1048 PM CST SUN NOV 16 2014

CEILINGS MOSTLY 3-5K FEET WITH A FEW AREAS OF CEILINGS 2-3K FEET.
AREAS OF VISIBILITIES 3-5SM IN BLOWING SNOW. OCCASIONAL SURFACE
GUSTS OF 25 TO 30 KNOTS FROM THE NORTHWEST. LITTLE CHANGE THROUGH
17/21Z WITH IMPROVEMENT LIKELY 17/21Z-18/0600Z AS WINDS SLOWLY
DECREASE.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...WINTER WEATHER ADVISORY FROM 10 AM TO 6 PM CST MONDAY FOR MNZ071-
     072-080-081-089-090-097-098.

IA...WINTER WEATHER ADVISORY FROM 10 AM TO 6 PM CST MONDAY FOR IAZ002-
     003-013-014-021-022.

NE...NONE.
&&

$$

UPDATE...MJ
SHORT TERM...08
LONG TERM...CHAPMAN
AVIATION...



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