Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 250245
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
945 PM CDT THU APR 24 2014

.UPDATE...
ISSUED AT 944 PM CDT THU APR 24 2014

THE EARLIER ISOLATED TO SCATTERED SHOWERS AND ROGUE THUNDER ACROSS
THE FAR NORTHEASTERN CWA HAVE PULLED EAST AND DISSIPATED WITH LOSS
OF DIURNAL SUPPORT AND EASTWARD PROGRESSION OF PV FEATURE THROUGH
MINNESOTA. OTHERWISE...MOST INTERESTING ASPECT TO WATCH FROM LATE
AFTERNOON AND EVENING WAS PROGRESSION OF THE DRYLINE WORK EASTWARD
ACROSS THE SIOUX FALLS AREA AND JUST INTO MN AND IA. LOOKING AT
RADAR VELOCITY...CAN MAKE A STRONG ARGUMENT THAT BOUNDARY WILL BE
UNABLE TO PROGRESS ANY MORE TONIGHT AND IS LIKELY TO WASH OUT
NEARLY IN PLACE...IF NOT BACK WESTWARD A BIT BEFORE DISSIPATING AS
A FEW HIGH RESOLUTION MODELS SUGGEST. THIS LEADS TO CONCERN THAT
THERE COULD BE A BIT OF PATCHY FOG IN LOW LYING AREAS WITH LACK OF
MIXING AND RECENT RAINFALL FOR AREAS NEAR/EAST OF THIS DISSIPATING
FEATURE. DO HAVE SOME MID TO HIGH CLOUDS WHICH WILL COMPLICATE
SKIES LATER TONIGHT...AND WILL CERTAINLY KEEP WHAT IS A MINOR
THREAT FOR PATCHY FOG EVEN MORE SO. NUDGED SOME TEMPS DOWN A FEW
DEGREES OVERNIGHT INTO THE LOWER THIRD OR SO GUIDANCE RANGE...
ESPECIALLY IN THOSE AREAS OF VERY DRY AIR WHICH ARE WEST OF THE
CURRENT BOUNDARY WITH EXPECTED LIGHT WINDS.  SHOULD BE A PLEASANT
FRIDAY WITH MIXING SUPPORTING MILD TEMPS AND FOR ONCE NOT MUCH
WIND ENERGY AROUND TO MIX DOWN.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 409 PM CDT THU APR 24 2014

RELATIVELY MIXY CONDITIONS ARE EXPECTED TO SUBSIDE THIS EVENING AS
LOW PRESSURE SHIFTS EAST AND GRADIENT WEAKENS. HIGH PRESSURE CENTER
IS EXPECTED TO SHIFT EAST SOUTH OF THE FORECAST AREA TONIGHT INTO
FRIDAY. WITH GOOD RADIATIVE CONDITIONS OVERNIGHT...CONSIDERED ADDING
FOG MENTION IN NW IOWA WHERE MIXING IS NOT AS STRONG AND HEAVIER
RAIN FELL.  STILL THINK THAT A FAIR AMOUNT OF THE MOISTURE WILL BE
ABLE TO MIX OUT OVER THE NEXT FEW HOURS...SO FOR NOW LEFT MENTION
OUT.  WITH RELATIVELY WEAK FLOW AND WINDS ALOFT GENERALLY IN THE 10
- 15 KNOT RANGE....SHOULD BE A RELATIVELY PLEASANT SPRING DAY ACROSS
THE AREA ON FRIDAY WITH 850 HPA TEMPS IN THE UPPER SINGLE DIGITS.
STILL WILL SEE A SLIGHTLY ELEVATED FIRE DANGER ON FRIDAY WITH
RELATIVELY DRY AIR RESULTING IN RH VALUES OF 20-30 PERCENT.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 409 PM CDT THU APR 24 2014

RIDGING SHIFTS EASTWARD ON SATURDAY AS A DEEP PACIFIC TROUGH
ADVANCES INTO THE FOUR CORNERS REGION. WINDY CONDITIONS DEVELOP AS
EAST SOUTHEAST WINDS INCREASE TO AROUND 20 TO 25 MPH WITH HIGHER
GUSTS BY THE AFTERNOON. MOISTURE GRADUALLY INCREASES DURING THE
DAY...RESULTING IN INCREASED MID AND HIGH CLOUDS. TEMPERATURES WILL
AGAIN BE QUITE MILD...ESPECIALLY NEAR THE MISSOURI VALLEY WHERE A BIT
MORE SUNSHINE AND WARMING IS EXPECTED. HIGHS WILL BE MAINLY IN THE
60S...WITH SOME 70S IN OUR SOUTH.

UNSETTLED WEATHER PATTERN SETS UP FOR THE FIRST HALF OF NEXT WEEK AS
THE PACIFIC TROUGH EMERGES IN THE CENTRAL HIGH PLAINS...LIFTS
NORTHWARD TO NEAR CENTRAL PORTIONS OF NEBRASKA AND SOUTH DAKOTA THEN
SLOWLY WOBBLES EASTWARD. STILL SEEING MODEL DIFFERENCES...
PARTICULARLY IN THE GRADUAL PROGRESSION EAST AND AWAY FROM THE
AREA.  THE GENERAL CONSENSUS WITH THE 12Z RUNS IS FOR A MORE
NORTHERLY TRACK...WHICH RESULTS IN SLIGHTLY MILDER TEMPERATURES AND
A GREATER POTENTIAL FOR THUNDERSTORMS. ADDITIONALLY...MODELS ARE
ALSO TRENDING TOWARDS A SLOWER EXIT OF THE UPPER LOW WHICH WILL
RESULT IN RAIN CHANCES LINGERING INTO THE END OF THE FORECAST PERIOD
ON THURSDAY.

GREATER MOISTURE ADVECTION WILL LEAD TO SOME MID LEVEL INSTABILITY
ON SATURDAY EVENING AND OVERNIGHT. STRONG DIRECTIONAL SHEAR AND
STEEP MID LEVEL LAPSE RATES SUGGEST THAT A FEW STRONG OR SEVERE
STORMS WILL BE POSSIBLE IF STORMS CAN MANAGE TO INITIATE. STORMS
BECOME MORE LIKELY ACROSS THE AREA OVERNIGHT AS THE UPPER LOW
EMERGES INTO THE PLAINS. COULD SEE PRECIPITATION BRIEFLY TAPER OFF
LATE SUNDAY MORNING INTO THE AFTERNOON...HOWEVER AS MUCH STRONGER
LIFT AND FORCING PUSHES INTO THE MISSOURI VALLEY...SHOWERS AND
STORMS WILL AGAIN BECOME NUMEROUS THROUGHOUT THE FORECAST AREA.
SHEAR REMAINS STRONG AT AROUND 40 KT...THOUGH MORE
UNIDIRECTIONAL...ALONG WITH DECENT INSTABILITY WILL POSE THE
POTENTIAL FOR SOME ISOLATED STRONG TO SEVERE STORMS. MOISTURE WILL
BE MORE COPIOUS ON SUNDAY THAN SATURDAY...SO THINK THAT
PRECIPITATION WILL BE MORE WIDESPREAD AND LIFT ACROSS THE AREA
THROUGH THE EARLY MORNING HOURS.

CLOUDY SKIES AND RAIN CHANCES PERSIST THROUGH AT LEAST TUESDAY AS
THE LARGE SYSTEM DRIFTS EASTWARD ACROSS THE REGION. WHILE THE MORE
NORTHERLY TRACK WILL RESULT IN A MILDER SYSTEM OVERALL...
TEMPERATURES WILL BE BELOW NORMAL MONDAY AND BEYOND. DID TREND HIGHS
AND LOWS SLIGHTLY WARMER...BUT EXPECT HIGHS TO GENERALLY TOP OUT IN
THE 50S TUESDAY THROUGH THURSDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 749 PM CDT THU APR 24 2014

GENERALLY EXPECT VFR CONDITIONS TO PREVAIL THROUGH THE PERIOD. WINDS
WILL BECOME LIGHT THIS EVENING AND REMAIN THAT WAY THROUGH TOMORROW.
THERE COULD BE SOME AREAS OF FOG THAT DEVELOP OVERNIGHT...BUT AT THIS
TIME EXPECT THE BEST CHANCE OF THIS WILL BE EAST OF THE TAF
SITES...ACROSS PORTIONS OF SOUTHWEST MINNESOTA AND ADJACENT AREAS OF
NORTHWEST IOWA.


&&

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

$$

UPDATE...CHAPMAN
SHORT TERM...
LONG TERM...
AVIATION...CHENARD






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