Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 280351
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1051 PM CDT WED APR 27 2016

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 401 PM CDT WED APR 27 2016

STRONG LOBE LIFTING NORTHWEST HAS BROUGHT A FAIR BREAK TO THE
STEADY RAIN TO THE SOUTHEAST PART OF THE AREA AND THIS WILL
CONTINUE PUSHING NORTHWEST...ALTHOUGH THIS LOBE WILL BE WEAKENING
AND EXPECT THAT THE CIRCULATION AND MINOR LOBES ROTATION AROUND
THE NORTHWEST SIDE WILL MAKE THE DECREASE MUCH MORE MODEST IN THE
HON/9V9 AREA WITH RAIN SLOWLY BECOMING MORE LIGHT AND SPOTTY.

AS THE UPPER LOW ITSELF APPROACHES THE SUX AREA...ANOTHER ROUND
OF SHOWERS AND STORMS WILL SPREAD INTO THE EASTERN PART OF THE
AREA THIS EVENING...SO AREAS THAT ARE SEEING A RAIN DECREASE NOW
WILL SEE IT PICK UP AGAIN DURING THE EVENING. SOME OF THIS RAIN
WILL CONTINUE TO SPREAD TO WEST OF THE JAMES RIVER...BUT AFTER
MIDNIGHT TONIGHT THE WHOLE RAIN AREA SHOULD BE SLOWLY DECREASING
IN INTENSITY AND ALSO DECREASING IN INTENSITY FROM THE SOUTH
SOUTHWEST. THIS SLOW DECREASING TREND SHOULD CONTINUE THURSDAY AS
LIGHT RAIN BECOMES MORE SPOTTY AND ENDS BY THE END OF THE DAY.

COOLING OVERNIGHT MAY BARELY BE ENOUGH TO GET A LITTLE MIXED
LIGHT SNOW WITH LINGERING RAIN IN SOME AREAS BUT WILL KEEP IT
MINIMAL WITH NO ACCUMULATION FOR LATE TONIGHT INTO THURSDAY
MORNING. CURRENT COOL SURFACE TEMPERATURES ARE OVERLAID WITH A
WARMER LAYER ALOFT. THESE COOL SURFACE TEMPERATURES MAY WARM A BIT
INTO THE EARLY EVENING AS THE MODEST WARM LAYER A BIT HIGHER
BEGINS TO COOL.

PLENTIFUL LOW LEVEL MOISTURE WILL STAY AROUND ON THE BACK SIDE OF
THE SLOWLY MOVING LOW THURSDAY...AND EXPECT CLOUDS TO STAY IN
THROUGH THE DAY. AFTER LOWS TONIGHT IN THE MID 30S WEST/NORTH TO
LOWER 40S SOUTHEAST...HIGHS THURSDAY SHOULD BE ONLY IN THE
40S...EXCEPT 50 OR SO AROUND SIOUX CITY.

GENERALLY NORTHEAST WINDS WILL VERY SLOWLY DECREASE TONIGHT AND
THURSDAY AS THE LOW WEAKENS.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 401 PM CDT WED APR 27 2016

MID-UPPER LEVEL RIDGE SHOULD BRING A BRIEF RESPITE FROM THE RAIN
TO THE REGION THURSDAY NIGHT AND FRIDAY...THOUGH TEMPERATURES
WILL REMAIN ON THE COOL SIDE. HAVE LOWERED THURSDAY NIGHT LOWS A
BIT... ESPECIALLY NORTH AS SURFACE RIDGE BRINGS SOME DRIER AIR
INTO AREAS NEAR/NORTH OF I-90. STILL EXPECT PLENTY OF CLOUD COVER
AT THIS TIME SO FROST POTENTIAL IS MINIMAL. HOWEVER...WILL HAVE TO
WATCH THIS AS CURRENT FORECAST LOWS DIP INTO THE MID 30S WITH THE
LIGHT WINDS. HIGHS FRIDAY WILL REBOUND TO AROUND 50 NEAR THE
MISSOURI VALLEY TO MID 50S NORTH OF I-90.

NEXT UPPER LOW SWINGS OUT OF THE CENTRAL ROCKIES INTO THE CENTRAL
PLAINS FRIDAY NIGHT/SATURDAY...BRINGING ANOTHER ROUND OF WIDESPREAD
RAIN TO THIS REGION AS BROAD SCALE LIFT INCREASES AHEAD OF THE UPPER
LOW. CIRCULATION FORECAST TO PASS A LITTLE FARTHER SOUTH WITH THIS
WAVE THAN THE CURRENT SYSTEM...SO NORTHERN EDGE OF PRECIP SHIELD
MORE LIKELY TO BE NEAR HIGHWAY 14 OR JUST SLIGHTLY NORTH...INSTEAD
OF NEAR THE SD/ND STATE BORDER AS WITH THE CURRENT SYSTEM. THIS WILL
MEAN POTENTIAL FOR ANOTHER INCH OR MORE OF RAIN FOR AREAS SOUTH OF
INTERSTATE 90...WHICH COULD BRING ADDITIONAL RIVER FLOOD CONCERNS.
AT THIS TIME...LOW LEVEL CONSENSUS MODEL TEMPERATURE PROFILES ARE
FORECAST TO BE SLIGHTLY WARMER THAN TONIGHT...SO HAVE NOT INCLUDED
ANY RAIN/SNOW MIX WITH THE PRECIPITATION FRIDAY NIGHT/SATURDAY.
HOWEVER ECMWF DOES SHOW SOME SUB-ZERO 850MB TEMPERATURES NORTH AND
WEST OF SIOUX FALLS LATE FRIDAY NIGHT/SATURDAY...SO WILL HAVE TO
MONITOR TRENDS OVER THE NEXT COUPLE OF RUNS.

RAIN CHANCES WILL LINGER THROUGH SATURDAY NIGHT INTO SUNDAY AS THE
SLOW MOVING TROUGH SLIPS EAST. THROUGHOUT THIS PERIOD FRIDAY NIGHT
TO SUNDAY...INSTABILITY LOCKED UP WELL SOUTH OF THE REGION...SO
LITTLE IF ANY THUNDER EXPECTED AND HAVE ONLY INCLUDED POTENTIAL FOR
ISOLATED THUNDER IN NORTHWEST IOWA SATURDAY AFTERNOON WHEN DRY SLOT
MAY NUDGE FAR ENOUGH NORTH TO ALLOW FOR SOME ELEVATED INSTABILITY.

STRONGER UPPER RIDGING TAKES HOLD EARLY NEXT WEEK...WHICH WILL ALLOW
TEMPERATURES TO WARM CLOSER TO EARLY MAY NORMALS IN THE MID-UPPER
60S BY TUESDAY AND WEDNESDAY. OPERATIONAL GFS A BIT OF AN OUTLIER IN
DRIVING ANOTHER TROUGH SOUTHEAST THROUGH THE NORTHERN PLAINS TUESDAY
NIGHT/WEDNESDAY AND GENERATING SOME SCATTERED RAIN CHANCES. OPTED TO
LEAVE THESE PERIODS DRY FOR NOW WITH ECMWF/GEM HOLDING ON TO MUCH
STRONGER RIDGE AXIS TO OUR WEST THROUGH MIDWEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1035 PM CDT WED APR 27 2016

LOW STRATUS WILL CONTINUE TO BLANKET THE AREA THROUGH MUCH OF THE
TAF PERIOD AS LIGHT RAIN SHOWERS ROTATE AROUND A SLOW MOVING UPPER
LEVEL LOW. EXPECT OCCASIONAL MVFR VISIBILITY IN RAIN...IN ADDITION
TO CEILINGS AROUND 700 TO 2000 FT AGL. MODELS SUGGEST SOME SLIGHT
IMPROVEMENT IN VISIBILITY LATE THURSDAY AFTERNOON INTO THURSDAY
EVENING...BUT WILL LEAVE TAFS PESSIMISTIC FOR THE TIME BEING.

&&

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

$$

SHORT TERM...
LONG TERM...JH
AVIATION...



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