455 
FXUS63 KFSD 262135
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
335 PM CST THU FEB 26 2015

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 335 PM CST THU FEB 26 2015

STRATOCU HAS DEVELOPED WITH AFTERNOON MIXING...RESULTING IN AT LEAST 
PARTLY CLOUDY SKIES ACROSS THE AREA. JUST ENOUGH LOW LEVEL 
INSTABILITY TO EVEN GET SCATTERED FLURRIES...MAINLY ACROSS NORTHWEST 
IOWA AND SOUTHWEST MINNESOTA. EXPECT CLOUDS AND FLURRIES TO BEGIN 
DISSIPATING TOWARDS SUNSET...GIVING WAY TO A CLEAR NIGHT. HIGH 
PRESSURE WILL MOVE OVERHEAD AS WELL...RESULTING IN LIGHT WINDS AND 
THUS PRETTY IDEAL RADIATIONAL COOLING CONDITIONS. GOT COLDER THAN 
FORECAST LAST NIGHT...AS WINDS SLACKED OFF ENOUGH TO ALLOW FOR SOME 
DECOUPLING. TRICKY LOW FORECAST TONIGHT...AS LIGHTER WINDS WILL 
ALLOW FOR A BIT BETTER RADIATING...BUT SLIGHTLY WARMER TEMPERATURES 
ALOFT WILL OFFSET THAT TO A DEGREE. THUS WENT COLDER THAN CONSENSUS 
BY SEVERAL DEGREES...BUT NOT QUITE AS LOW AS THE COLDEST GUIDANCE. 
THIS RESULTS IN READINGS MAINLY BETWEEN -10 AND -15 IN OUR SNOW 
COVERED AREAS...AND -5 TO -10 TOWARDS THE MISSOURI RIVER WHERE SNOW 
COVER IS LESS. PROBABLY WILL SEE A FEW OF THE NORMALLY COLDER SPOTS 
IN SOUTHWEST MINNESOTA AND NORTHWEST IOWA DROP EVEN A BIT LOWER THAN 
-15. GIVEN THE LIGHT WINDS WILL HOLD OFF ON A WIND CHILL 
ADVISORY...ALTHOUGH ANY LIGHT BREEZE AT ALL WILL PUSH READINGS TO 
AROUND -25. 

ANOTHER WELL BELOW NORMAL TEMPERATURE DAY ON FRIDAY. THE SNOW COVER 
AND SOUTHERLY FLOW ON THE BACKSIDE OF THE HIGH DO NOT SUPPORT GOOD 
MIXING. THUS THINKING WE ONLY SEE LOW TO MID TEENS IN OUR EAST. OUR 
WESTERN AREAS WILL SEE SLIGHTLY BETTER WARMING ALOFT...AND HAVE LESS 
OR NO SNOW COVER...SO THINKING LOW TO MID 20S FROM YANKTON TO 
MITCHELL AND POINTS WEST. SIGNAL FOR STRATOCU SEEMS LESS 
TOMORROW...SO KEPT SKIES SUNNY...ALTHOUGH AN NOT RULE OUT A FEW 
AFTERNOON CLOUDS.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 335 PM CST THU FEB 26 2015

FRIDAY NIGHT INTO SATURDAY MORNING WILL SEE HIGH PRESSURE SHIFT EAST 
WITH RETURN FLOW TRYING TO SET UP. SOMEWHAT OF AN INVERSION COULD 
PLAY A ROLE IN JUST HOW MUCH THE SOUTHERLY WINDS CAN STIR THINGS UP 
SO FOR NOW WILL NOT GO TOO CRAZY WITH THE NON DIURNAL TEMPERATURES. 
LOWS SHOULD BE NEAR ZERO IN THE EAST AND NEAR 10 ABOVE IN CENTRAL 
SD.

A WEAK INVERTED TROUGH AND WEAK WAVE PASS THROUGH THE AREA ON MAINLY 
ON SATURDAY AFTERNOON AND EVENING WITH A SLIGHTLY BETTER THREAT FOR 
LIGHT SNOW OVER THE EASTERN PART OF THE CWA. WILL KEEP POPS LOW AS 
SYSTEM NOT OVERLY ORGANIZED BUT WILL NOT BE SURPRISED TO SEE A 
LITTLE LIGHT SNOW...ESPECIALLY IN NORTHWEST IOWA.

THE THREAT FOR SNOW WILL SLIP SOUTH OF THE AREA ON SATURDAY NIGHT 
LEAVING A MARGINALLY CHILLY AIR MASS IN PLACE ON SUNDAY. NORTHWEST 
WINDS GENERALLY 10 TO 20 MPH WITH HIGHS MAINLY IN THE 20S.

IN THE OUTER PERIODS (MONDAY THROUGH THURSDAY)...STILL SOME STRONG 
HINTS OF A POTENTIAL WINTER SYSTEM MONDAY INTO TUESDAY. WILL AIM THE 
HIGHEST POPS IN FOR MONDAY NIGHT AND TUESDAY AND ESPECIALLY OVER THE 
SOUTHEASTERN HALF OF THE CWA. WILL CONTINUE TO KEEP TEMPERATURES 
BELOW NORMAL...PRETTY CLOSE TO NORMAL ON MONDAY AND TUESDAY...THEN 
ANOTHER SURGE OF COLD AIR AND WELL BELOW NORMAL WEDNESDAY AND 
THURSDAY. COULD BE WELL BELOW NORMAL IF WE END UP GETTING A SWATH OF 
3 TO 6 INCHES OF SNOW. RIGHT NOW CONFIDENCE IS MARGINAL WITH THIS 
SYSTEM AS HINTS ARE THE MAIN EFFECTS WILL BE SOUTH OF THE CWA AND 
THERE ARE ALSO SOME DECENT DIFFERENCES IN THE LOW LEVEL THERMAL 
FIELD. NOT EVEN OUT OF THE QUESTION TO SEE SOME MIXED PRECIPITATION 
IN MAINLY NORTHWEST IOWA IF SOMETHING CLOSER TO THE GFS VERIFIES. SO 
OVERALL A LOT OF OPEN ENDED POTENTIAL FOR NOW AND DIFFICULT TO LEAN 
IN ANY ONE DIRECTION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1122 AM CST THU FEB 26 2015

DEVELOPING STRATOCU HAS BECOME BROKEN MVFR ACROSS SOUTH CENTRAL
SOUTH DAKOTA. EXPECTING AT LEAST SCATTERED CONDITIONS AT THE TAF
SITES THIS AFTERNOON...BUT CAN NOT RULE OUT A PERIOD OF BROKEN
CONDITIONS. EITHER WAY CLOUDS SHOULD CLEAR TOWARDS SUNSET
RESULTING IN VFR CONDITIONS PREVAILING TONIGHT INTO FRIDAY
MORNING.

&&

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

$$

SHORT TERM...CHENARD
LONG TERM...08
AVIATION...CHENARD