Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 012322
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
622 PM CDT FRI AUG 1 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 317 PM CDT FRI AUG 1 2014

AN UPPER LEVEL WAVE WILL MOVE SOUTHEAST FROM NORTH DAKOTA INTO
CENTRAL SOUTH DAKOTA BY MIDNIGHT. THERE HAS BEEN AT LEAST ISOLATED
CONVECTION WITH THIS WAVE MOST OF THE DAY. WITH LAPSE RATES EXPECTED
TO BE AROUND 7 C/KM OVERNIGHT...WILL HAVE 200 TO 400 J/KG BASED
ABOVE 800 MB AS THIS WAVE MOVES IN. SO AM EXPECTING ISOLATED TO
SCATTERED ELEVATED CONVECTION TO DEVELOP IN CENTRAL SD AND THEN
SPREAD SOUTHEAST OVERNIGHT. HAVE RAISED POPS TO 30 PERCENT FROM
AFTER MIDNIGHT INTO SATURDAY MORNING IN THE MISSOURI VALLEY
INCLUDING SIOUX CITY. WITH THE WAVE EXPECTED TO MOVE INTO NE AND
WEST CENTRAL IOWA...DO NOT EXPECT CONVECTION TO GET AS FAR EAST AS
SOUTHWEST MINNESOTA AND SPENCER IOWA. THERE COULD ALSO BE SOME LIGHT
FOG TOMORROW AROUND SIOUX CITY AND INTO NORTHWEST IOWA. AM A LITTLE
MORE UNCERTAIN ABOUT THE FOG GIVEN LOWER DEW POINTS THIS AFTERNOON
SO DID NOT INCLUDE IN THE FORECAST. LOWS OVERNIGHT WILL BE AROUND 60
ACROSS THE AREA.

AS MENTIONED ABOVE...THE UPPER LEVEL WAVE WILL MOVE ACROSS THE MID
MISSOURI VALLEY IN THE MORNING BRINGING A CHANCE OF THUNDERSTORMS.
THESE STORMS ARE EXPECTED TO MOVE INTO SOUTHEAST NEBRASKA AND
SOUTHERN IOWA BY EARLY AFTERNOON WITH SKIES BECOMING PARTLY TO
MOSTLY SUNNY. WITH INCREASING SOUTH FLOW AND A BUILDING UPPER
RIDGE...WARMER AIR WILL SLOWLY MOVE EAST WITH HIGHS REACHING THE 80S
ACROSS THE AREA.  AROUND CHAMBERLAIN...A FEW LOCALES COULD REACH 90
DEGREES.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 317 PM CDT FRI AUG 1 2014

SATURDAY NIGHT WILL SEE MARGINAL INSTABILITY AND LAPSE RATES ALOFT
WHICH WILL SUPPORT THE STANDARD NOCTURNAL WEAK SHOWER AND
THUNDERSTORM THREAT. THIS SHOULD CONTINUE INTO SUNDAY BUT AGAIN
REMAIN PRETTY ISOLATED. NOT EXPECTING ANYTHING SEVERE. LOWS ON
SATURDAY NIGHT IN THE LOWER 60S WITH HIGHS ON SUNDAY POSSIBLY A BIT
HOT IN THE WESTERN CWA...FROM ABOUT 90 TO 95 WHILE THE EASTERN CWA
WILL BE ABOUT 80 TO 85.

SUNDAY NIGHT INTO MONDAY WILL SEE A MINOR THREAT FOR SHOWERS AND
THUNDERSTORMS...MAINLY OVER THE FAR EASTERN AND NORTHERN CWA.
AGAIN...NOTHING SEVERE. SIMILAR LOWS AND HIGHS TO SATURDAY NIGHT
INTO SUNDAY.

MONDAY NIGHT WILL SEE A SLIGHTLY STRONGER WAVE MOVE THROUGH THE FAR
NORTHERN PLAINS WHICH WILL BRING AN INCREASED THREAT FOR SHOWERS
AND THUNDERSTORMS...BUT BETTER CHANCES STILL LOOK TO COME ON TUESDAY
AND WEDNESDAY. BETTER CHANCES AGAIN OVER THE NORTHERN AND EASTERN
CWA. LOWS ON MONDAY NIGHT IN THE MID TO UPPER 60S.

IN THE OUTER PERIODS(TUESDAY THROUGH FRIDAY)...UPPER LEVEL RIDGING
OVER THE ROCKIES WILL BATTLE TROUGHING ACROSS SOUTHERN CANADA
THROUGH THE PERIOD. THE MODELS HAVE BEEN CONSISTENTLY INCONSISTENT
DURING THIS TIME FRAME AND WILL LIKELY CONTINUE TO DO SO AS THE
MODELS TRY TO RESOLVE THE ENERGY OVER SOUTHERN CANADA. WILL KEEP
POPS IN THE 50 TO 70 PERCENT RANGE FOR TUESDAY NIGHT INTO WEDNESDAY.
STILL EXPECTING A DECENT LOW LEVEL BOUNDARY WITH WHAT LOOKS TO BE A
PRETTY DECENT WAVE DURING THIS TIME. THURSDAY INTO FRIDAY
PRECIPITATION CHANCES WILL DECREASE BUT CONFIDENCE NOT REAL WILL
WITH THE ABOVE MENTIONED INCONSISTENCIES. AS FOR TEMPERATURES WILL
LIKELY KEEP THINGS ON THE COOL SIDE. THE ECMWF VALUES ARE COOLER
THAN THE GFS VALUES THROUGH THIS PERIOD AND WITH MEN TEMPERATURES
LOWER THAN MEX TEMPERATURES...WHICH ARE ALREADY BELOW
CLIMATOLOGY...THERE IS A PRETTY GOOD STATISTICAL SIGNAL TO REMAIN ON
THE COOL SIDE AS WELL.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 622 PM CDT FRI AUG 1 2014

VFR IS ANTICIPATED THROUGH SATURDAY WITH THE EXCEPTION OF THE KSUX
TAF SITE...WHERE IFR TO MVFR FOG COULD ONCE AGAIN DEVELOP AROUND
SUNRISE. IF THE FOG BECOMES MORE DENSE THAN IFR...IT WILL LIKELY
BE BRIEF AND SHALLOW. OTHERWISE ISOLATED TO SCATTERED CONVECTION
WILL OCCUR IN CENTRAL SD TONIGHT...BUT AT THIS TIME THE PROBABILITIES
OF IT IMPACTING THE KHON TAF SITE IS TOO LOW TO MENTION. THE
CHANCES FOR CONVECTION ARE EVEN LOWER AT KSUX AND KFSD. THAT
SAID...THE DISTURBANCE WILL LIKELY CREATE PLENTY OF MID LEVEL
CLOUDS IN THE FORECAST AREA LATER TONIGHT AND SATURDAY MORNING.

&&

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

$$

SHORT TERM...SCHUMACHER
LONG TERM...08
AVIATION...MJ






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