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 011113
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
513 AM CST SUN MAR 1 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM CST SUN MAR 1 2015

WITH A PASSAGE OF A FRONTAL BOUNDARY THIS MORNING LOW LEVEL FLOW
WILL BECOME WEST/NORTHWESTERLY TODAY...AND WITH DECENT MIXING AND
THERMAL PROFILES SIMILAR TO OR SLIGHTLY MILDER THAN
YESTERDAY...HIGHS WILL CLIMB INTO THE UPPER 20S TO MID 30S ACROSS
THE AREA. PER MODEL RH TIME SECTIONS AND CURRENT SATELLITE
IMAGES...MID CLOUDS WILL STREAM ACROSS THE REGION THROUGH THE EARLY
PART OF THE DAY...THEN TRENDING TOWARD DECREASING CLOUDS IN THE
LATER AFTERNOON AS HIGH PRESSURE BUILDS INTO THE AREA AND AN UPPER
LEVEL SHORTWAVE DROPPING THROUGH THE NORTHERN PLAINS PEELS OFF TO
THE EAST.

THE SURFACE RIDGES AXIS SLIDES THROUGH THE AREA TONIGHT. WITH
THIS...SKIES WILL BE MOSTLY CLEAR THROUGH A GOOD BIT OF THE
NIGHT...AND WINDS WILL DROP OFF IN THE RELAXING GRADIENT. THIS WILL
ALLOW TEMPERATURES TO DROP BACK DOWN INTO THE SINGLE DIGITS FOR MUCH
OF THE AREA. THE EXCEPTION WILL BE THROUGH THE MISSOURI RIVER
CORRIDOR WHERE INCREASING CLOUDS LATER IN THE NIGHT AND AN EVOLVING
SOUTHERLY FLOW ON THE BACK SIDE OF THE HIGH WILL KEEP READINGS IN
THE LOWER TEENS.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 434 AM CST SUN MAR 1 2015

FOCUS REMAINS ON SNOW EVENT SLATED TO AFFECT THE REGION MONDAY NIGHT
INTO TUESDAY. MONDAY SHOULD BE A MILD BUT BREEZY DAY AHEAD OF THE
SYSTEM. MODELS CONTINUE TO OUTPUT SOME LIGHT PRECIP AS MID LEVEL
FRONT MOVES INTO THE REGION AHEAD OF THE WAVE. WILL CONTINUE A
SLIGHT CHANCE ACROSS MAINLY SOUTHERN PORTIONS OF THE AREA IN THE
LATE AFTERNOON...WITH CHANCES INCREASING A BIT MONDAY EVENING AS THE
MID LEVEL FRONT LIFTS FARTHER NORTHEAST INTO SOUTHWEST MN...THOUGH
ANTICIPATE VERY LIGHT AMOUNTS WITH THIS INITIAL PRECIPITATION.

MORE EXPANSIVE DEVELOPMENT EXPECTED LATER MONDAY NIGHT AS THE MID
LEVEL FRONT STRENGTHENS OVER THE CWA. GFS/NAM HAVE TRENDED A BIT
FARTHER NORTH WITH THE FRONTAL BOUNDARY...WHILE GEM/ECMWF HOLD IT
CLOSER TO A LAKE ANDES-SIOUX FALLS-WINDOM LINE BY 12Z TUESDAY. THINK
MOST AREAS HAVE A STRONG CHANCE OF SEEING MEASURABLE SNOWFALL DURING
THIS PERIOD...THOUGH STILL QUITE A BIT OF UNCERTAINTY REGARDING THE
LOCATION OF ANY HEAVIER BANDS WHICH MAY DEVELOP. HAVE SHIFTED OUR
AXIS SLIGHTLY NORTHWARD...THOUGH NOT AS FAR AS MODEL QPF WOULD
SUGGEST. GFS REMAINS THE ONLY MODEL POINTING TO A WARM LAYER ABOVE
FREEZING WORKING INTO THE FAR SOUTHERN CWA...AND FORECAST SOUNDINGS
FOR KSUX BARELY SUPPORTIVE OF ANYTHING OTHER THAN SNOW. SO HAVE
REMOVED SLEET MENTION FOR NOW...THOUGH CANNOT COMPLETELY RULE IT OUT
IF GFS TEMPERATURES VERIFY.

WAVE AND ASSOCIATED SNOW CHANCES MOVE THROUGH MUCH OF THE FORECAST
AREA BY MIDDAY TUESDAY...WITH MOST MODELS COMPLETELY DRY BY TUESDAY
AFTERNOON. WILL HANG ONTO A LOW CHANCE ACROSS OUR SOUTHEAST TO ALLOW
FOR POSSIBLE SLOWER TIMING IN FUTURE RUNS...BUT CURRENTLY ANTICIPATE
LITTLE IF ANY ADDITIONAL ACCUMULATION AFTER 18Z TUESDAY. STRONG WIND
MAY BE THE GREATER HAZARD WITH THIS SYSTEM...AS 35-40KT POST-FRONTAL
WINDS MIX TO THE SURFACE. CURRENTLY HAVE SNOWFALL AMOUNTS IN 1.5-3
INCH RANGE...WITH HIGHEST TOTALS IN SOUTHWEST MINNESOTA. THIS ALONE
WOULD NOT WARRANT HEADLINES. HOWEVER THE STRONG WINDS WILL BRING AN
ADDED THREAT OF BLOWING SNOW. CURRENTLY THINKING THAT FALLING SNOW
WILL BE WINDING DOWN AS THE STRONGER WINDS BEGIN TO MOVE IN...WHICH
COULD LIMIT BLOWING SNOW SOMEWHAT. IF TIMING OF STRONGER WINDS WERE
MORE COINCIDENT WITH WHEN SNOW WILL BE FALLING...AND IF CONFIDENCE
WERE GREATER IN PROJECTED SNOWFALL AMOUNTS/LOCATION...WOULD CONSIDER
A WATCH TO COVER THE COMBINED SNOW/BLOWING SNOW THREAT. HOWEVER...
CONFIDENCE IS NOT THAT GREAT AT THIS TIME...SO DECIDED TO HOLD OFF
ON ANY HEADLINES AND WILL CONTINUE TO HIGHLIGHT THREATS IN THE HWO
FOR NOW.

AS FOR TEMPERATURES...STILL LOOKING AT EARLY MORNING HIGHS ACROSS
THE AREA WITH TEMPS FALLING THROUGHOUT THE DAY TUESDAY. WINDS WILL
DIMINISH BY LATE TUESDAY EVENING BUT STILL ENOUGH AROUND AS TEMPS
FALL BELOW ZERO TUESDAY NIGHT THAT WIND CHILL HEADLINES WILL LIKELY
BE NEEDED. SURFACE RIDGE BRINGS LIGHT WINDS BY WEDNESDAY EVENING...
BUT SPEEDS INCREASE IN RETURN FLOW AGAIN LATER WEDNESDAY NIGHT. WILL
PROBABLY SEE SOME NON-DIURNAL TEMPERATURE TRENDS AGAIN WEDNESDAY
NIGHT AS A RESULT...THOUGH SOME AREAS WILL LIKELY STILL DIP INTO
WIND CHILL ADVISORY RANGE AT SOME POINT DURING THE PRE-DAWN HOURS.

WARMER TEMPERATURES STILL ON TRACK FOR LATE NEXT WEEK...THOUGH JUST
HOW WARM WILL DEPEND ON EXTENT OF SNOWFALL EARLY IN THE WEEK. GIVEN
THE UNCERTAINTIES DISCUSSED ABOVE REGARDING SNOWFALL LOCATION...WILL
NOT STRAY TOO FAR FROM MODEL GUIDANCE BLEND AT THIS TIME.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 512 AM CST SUN MAR 1 2015

VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD.

&&

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

$$

SHORT TERM...JM
LONG TERM...
AVIATION...JM


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