National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KFSD 160347
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1047 PM CDT SAT JUN 15 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 459 PM CDT SAT JUN 15 2013

HIGH PRESSURE WILL BE CENTERED OVER THE BIG SIOUX VALLEY MUCH OF
TONIGHT. ANY CU LATE THIS AFTERNOON SHOULD RAPIDLY DISSIPATE WITH
LOSS OF HEATING LEAVING MOSTLY CLEAR SKIES. DO EXPECT TO SEE SOME
HIGHER CLOUDS MOVE INTO THE SOUTH CENTRAL SOUTH DAKOTA TOWARD DAY
BREAK. ALSO WINDS WILL BE LIGHT OVERNIGHT AND WITH MUCH OF THE AREA
RECEIVING RAIN THIS MORNING...THERE DOES REMAIN SOME RESIDUAL
MOISTURE IN THE BOUNDARY LAYER. BUT WITH SHORT NIGHT...AM NOT
EXPECTING DENSE FOG...INSTEAD LIGHT FOG THAT MAY REDUCE
VISIBILITIES TO 3-5 MILES SO NOT GOING TO ADD TO THE PUBLIC
FORECAST AT THIS TIME. LOWS OVERNIGHT ARE EXPECTED TO DROP INTO
THE 50S.

ON SUNDAY A WEAK CONVERGENCE BOUNDARY WILL MOVE INTO EASTERN SD
BY THE AFTERNOON. 700-500 MB LAPSE RATES ARE AROUND 8 C/KM AND THE
0-6 KM BULK SHEAR IS FROM 35 TO 45 KTS. THAT MAY HELP TO PROVIDE
SOME ORGANIZATION TO STORMS TO SUPPORT AT LEAST MULTICELLS. THE
LIMITING FACTOR IS DEEP LOW LEVEL MOISTURE. SOUTHERLY FLOW WILL
ONLY PERSIST FOR A FEW HOURS PRIOR TO THE BOUNDARY ARRIVING SO THAT
MEANS MLCAPES WILL GENERALLY BE LESS THAN 1000 J/KG BY MID TO LATE
AFTERNOON. WHILE A COUPLE OF STORMS MAY GET SMALL HAIL...SEVERE
WEATHER APPEARS UNLIKELY AT THIS TIME UNLESS MOISTURE RETURN IS
GREATER THAN CURRENTLY ANTICIPATED.

THE UPPER WAVE NEAR THE BOUNDARY IS RATHER WEAK WITH LITTLE
PRESSURE ADVECTION ON THE TROPOPAUSE. THE GREATEST INSTABILITY
WILL ACTUALLY BE WEST OF THE MISSOURI RIVER AND INTO NEBRASKA.
WHILE SCATTERED THUNDERSTORMS LOOK TO DEVELOP ACROSS THE WESTERN
HIGH PLAINS...THE QUESTION WILL BE HOW FAR EAST THEY CAN GET WITH
LIMITED MOISTURE. ALSO EVENTUALLY STORMS IN NEBRASKA WILL LIKELY
BECOME DOMINANT DUE TO BETTER INSTABILITY AND MOISTURE AND THAT
MAY LIMIT EASTWARD EXTEND OF CONVECTION LATE SUNDAY AFTERNOON AS WELL.
THUS KEPT ONLY CHANCE POPS...PRIMARILY WEST OF I29 THROUGH THE
DAY. WITH AT LEAST SOME SUN THROUGH MUCH OF THE MORNING INTO THE
AFTERNOON...ESPECIALLY EAST OF THE JAMES RIVER...HIGHS ARE
EXPECTED TO BE IN THE 80S.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 253 PM CDT SAT JUN 15 2013

MONDAY NIGHT INTO TUESDAY WILL SEE HIGH PRESSURE SETTLE INTO
MINNESOTA THEN GRADUALLY PUSH EASTWARD. THIS WILL ALLOW FOR A COOL
NIGHT WITH LOWS IN THE LOWER TO MIDDLE 50S. AS THE HIGH MOVES EAST A
VERY NICE DAY IS EXPECTED TUESDAY AS WINDS INCREASE GRADUALLY FROM
THE SOUTHEAST AND TEMPERATURES TOP OUT AROUND 80S DEGREES IN MOST
SPOTS.

FOR THE WEDNESDAY THROUGH FRIDAY TIMEFRAME UPPER LEVEL RIDGING WILL
TRY TO DEVELOP DURING THIS TIME SO THERE IS A POTENTIAL FOR A LITTLE
QUIETER PERIOD. HOWEVER...WITH A FAIRLY STRONG LOW PRESSURE ROTATING
OVER THE NORTHWESTERN UNITED STATES THERE WILL BE A DECENT POTENTIAL
FOR WAVES TO EJECT ONTO THE NORTHERN PLAINS. SO WILL HAVE A DECENT
CHANCE FOR NIGHT TIME AND MORNING THUNDERSTORMS DURING THIS PERIOD
WITH FRIDAY NIGHT INTO SATURDAY LOOKING LIKE THE BEST POTENTIAL.
TEMPERATURES CONTINUE TO MODERATE AND WARM...BUT SUMMERTIME HEAT AND
HUMIDITY IS NOT AT THIS TIME EXPECTED WITH HIGHS MAINLY FROM THE
UPPER 70S TO MID 80S AND LOWS IN THE 60S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1047 PM CDT SAT JUN 15 2013

VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE TAF PERIOD AS
HIGH PRESSURE BUILDS OVER THE REGION. RESIDUAL MOISTURE...LIGHT
WINDS AND CLEAR SKIES WILL BE FAVORABLE FOR SOME LIGHT RADIATIONAL
FOG TO DEVELOP...MAINLY ACROSS NW IOWA AND POSSIBLE AFFECTING THE
KSUX TAF SITE LATE TONIGHT. CHANCE OF THUNDERSTORMS INCREASES
AFTER 18Z SUNDAY...MAINLY AT THE KHON TAF SITE. WILL KEEP OUT OF
KHON TAF AT THIS TIME AS MUCH OF THE CONVECTION LOOKS TO REMAIN
W/SW OF THERE.

&&

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

$$

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