000
FXUS63 KFSD 200852
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
352 AM CDT SUN APR 20 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT SUN APR 20 2014

THUS FAR SEEING LITTLE MORE THAN VERY LIGHT ECHOES DEVELOP ALONG
STATIONARY BOUNDARY IN OUR FAR SOUTHEAST CWA...INDICATIVE OF MEAGER
LIFT IN SPLIT FLOW PATTERN ALOFT. AS A RESULT...HAVE TRIMMED BACK
POPS TO JUST 20-30 PERCENT THROUGH THE EARLY MORNING HOURS...THEN
ENDING ALTOGETHER MID-LATE MORNING AS MID LEVEL RIDGING DIMINISHES
LIFT EVEN FURTHER. BOUNDARY REMAINS IN THE SOUTHEAST THROUGH THE
AFTERNOON...BUT BECOMES MORE DIFFUSE AS IT LIFTS A BIT FURTHER TO
THE NORTHWEST AHEAD OF SUBTLE LOW PRESSURE AND NORTH-SOUTH TROUGH
PUSHING INTO CENTRAL DAKOTAS. MOISTURE INCREASING ALONG THE BOUNDARY
IN NORTHWEST IOWA ALONG WITH STRONG HEATING INTO THE 70S WILL RESULT
IN INCREASED INSTABILITY/WEAKENING 850MB CAP THIS AFTERNOON...AND
SHOULD SEE AT LEAST SCATTERED SHOWERS/ISOLATED THUNDERSTORMS DEVELOP
ACROSS SOUTHEAST PORTIONS OF THE CWA BY MID-LATE AFTERNOON. DESPITE
BETTER INSTABILITY...FORECAST SOUNDINGS SHOW THIN/TALL CAPE PROFILES
AND MINIMAL SHEAR...SO NO SEVERE THREAT WITH ANY STORMS THAT DEVELOP.

TOWARD EARLY EVENING...ALSO START TO SEE WEAK EXTENSION OF NORTHERN
STREAM WAVE SWING INTO CENTRAL SD...INTERACTING WITH AFOREMENTIONED
LOW LEVEL BOUNDARY THERE. WORTH A MENTION OF SHOWERS AND MAYBE A FEW
THUNDERSTORMS AS THE BOUNDARY TRACKS EAST ACROSS SOUTHEAST SD DURING
THE EVENING...THOUGH THIS AREA HAS LESS LOW LEVEL MOISTURE TO WORK
WITH...SO WILL LIMIT POPS TO 20-30 PERCENT FOR NOW. BOUNDARY SHOULD
BE CLOSE TO EXITING FAR SOUTHEAST CORNER OF THE DAY BY EARLY MONDAY
MORNING...AND ANY THREAT OF SHOWERS/THUNDERSTORMS SHOULD DIMINISH AS
WELL...WITH STRONG DRYING BEHIND THE BOUNDARY.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 352 AM CDT SUN APR 20 2014

THE SYSTEM WILL PULL OFF TO THE EAST BY MONDAY MORNING WITH SURFACE
HIGH PRESSURE BUILDING SOUTHWARD INTO THE REGION. THIS WILL RESULT
IN CLEARING SKIES...AND BREEZY CONDITIONS THROUGH THE AFTERNOON WITH
COLD AIR ADVECTION/STEEP LOW LEVEL LAPSE RATES BEHIND THE DEPARTING
SYSTEM. MODELS HAVE BEEN COMING IN TOO HIGH WITH RESPECT TO DEW
POINTS OF LATE...SO WENT ON THE LOW SIDE OF GUIDANCE WITH DEW POINTS
ON MONDAY. THIS RESULTED IN AFTERNOON RELATIVE HUMIDITY PERCENTAGE
VALUES IN THE LOWER TO MID 20S OVER OUR ALL BUT OUR NORTHEASTERN
AREAS...AND WITH THE AFOREMENTIONED WINDS WILL SEE AN ENHANCED FIRE
DANGER ACROSS THE AREA. AS FOR HIGHS...IN A COLD AIR ADVECTION
REGIME HIGHS IN THE MID 60S TO LOWER 70S STILL SEEMS APPROPRIATE.
THE SURFACE RIDGE AXIS SLIDES OVERHEAD ON MONDAY NIGHT...AND WITH
CLEAR SKIES AND WINDS BECOMING VERY LIGHT WENT ON THE LOW SIDE OF
GUIDANCE WITH RESPECT TO LOWS...MID AND UPPER 30S ACROSS THE CWA.

ON TUESDAY THE HIGH BEGINS TO MOVE OFF TO THE EAST...WITH A
SOUTHEASTERLY SURFACE FLOW RETURNING TO THE AREA DURING THE DAY. IT
WILL BECOME BREEZY IN OUR WEST THROUGH THE DAY IN A TIGHTENING
GRADIENT AS A SURFACE TROUGH NUDGES OUT OF THE ROCKIES. THERMAL
PROFILES CONTINUE TO COOL A BIT IN OUR EAST...SO LOOKING AT HIGHS IN
THE LOWER 60S OVER EAST CENTRAL SOUTH DAKOTA AND SOUTHWESTERN
MINNESOTA...WHILE READINGS WILL CLIMB INTO THE LOWER 70S THROUGH
SOUTH CENTRAL SOUTH DAKOTA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1051 PM CDT SAT APR 19 2014

VFR CONDITIONS WILL PREVAIL FOR THE REMAINDER OF TONIGHT THROUGH
SUNDAY EVENING. WINDS WILL ALSO BE FAIRLY LIGHT. A WIND SHIFT
BOUNDARY WILL STALL NEAR THE KSUX TAF SITE THROUGH THE PERIOD...SO
WIND DIRECTIONS ARE A BIT TRICKY FOR THAT SITE. BUT AGAIN...WINDS
LOOK LIGHT AT ANY RATE. FOR NOW...ONLY MENTIONED PRECIPITATION FOR
THE KSUX TAF SITE BETWEEN 09Z AND 15Z SUNDAY IN THE FORM OF
SHOWERS. THE NEXT SHORT WAVE WILL MOVE NORTHEASTWARD ALONG THE
STALLED SURFACE BOUNDARY POSSIBLY GIVING SOME RAINFALL FOR THAT
AREA. AND CURRENTLY THERE ARE SOME DEVELOPING SHOWERS AND ISOLATED
THUNDERSTORMS IN NORTHWEST KS AND SOUTH CENTRAL NEB MOVING
NORTHEASTWARD. BUT OTHERWISE FOR NOW...LEFT BOTH KFSD AND KSUX DRY
AS CHANCES LOOK TOO SKITTISH TO MENTION RAIN OR THUNDERSTORMS FOR
ANY GIVEN POINT LOCATION.

&&

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

$$

SHORT TERM...JH
LONG TERM...JM
AVIATION...MJ