Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 042347
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
647 PM CDT MON MAY 4 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 415 PM CDT MON MAY 4 2015

PERSISTENT DRY INFLOW IN THE LOWER-MID LEVELS HAS KEPT RAIN AT BAY
IN MOST AREAS THROUGH THE AFTERNOON...WITH EXCEPTION OF FAR SOUTHERN
AREAS WHICH HAVE BEEN ABLE TO SATURATE MORE DEEPLY...ALLOWING SOME
SPRINKLES TO REACH THE SURFACE. MOST MODELS MAINTAIN THIS TREND WELL
THROUGH THE EVENING AND EVEN MUCH OF TONIGHT...AND HAVE TRIMMED POPS
FROM AREAS NORTH OF I-90 UNTIL AFTER 12Z TUESDAY...AND EVEN FROM
AREAS NORTH OF HIGHWAY 18 UNTIL LATE TONIGHT. EASTERLY WINDS WILL
CONTINUE...THOUGH GUSTINESS SHOULD DIMINISH THIS EVENING. THE WINDS
ALONG WITH A FAIR AMOUNT OF CLOUD COVER SHOULD HOLD TEMPERATURES UP
IN THE MID 40S TO MID 50S.

AS MID-UPPER RIDGE AXIS BEGINS TO LIFT NORTHEAST TOWARD THE GREAT
LAKES ON TUESDAY...WILL BEGIN TO FEEL MORE INFLUENCE FROM BROAD
WESTERN CONUS TROUGH SWINGING THROUGH THE ROCKIES. THIS SHOULD
GRADUALLY ALLOW AT LEAST SCATTERED PRECIP TO EXPAND NORTH THROUGH
MOST OF THE CWA. DO NOT ANTICIPATE RAINFALL BECOMING VERY HEAVY
DURING THE DAYLIGHT HOURS...GENERALLY AROUND A TENTH OF AN INCH OR
LESS...WITH HIGHEST AMOUNTS FROM NORTHWEST IOWA WESTWARD THROUGH THE
MISSOURI RIVER VALLEY. DESPITE FAIRLY WIDESPREAD CLOUD COVER AND
SOUTHEAST WINDS WHICH ARE TYPICALLY LESS FAVORABLE FOR MIXING...
SHOULD STILL BE A FAIRLY MILD DAY WITH HIGHS IN THE UPPER 60S TO
LOWER 70S. CONVECTIVE CHANCES LOOK PRETTY MEAGER THROUGH MOST OF
THIS PERIOD...THOUGH COULD SEE A FEW MORE GENERIC THUNDERSTORMS WITH
MODEST INCREASE IN INSTABILITY THROUGH THE AFTERNOON.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 415 PM CDT MON MAY 4 2015

THE UPPER LEVEL SHORTWAVE OVER EASTERN COLORADO WILL CONTINUE TO
LIFT NORTHWARD ON TUESDAY NIGHT. OUT AHEAD OF THIS A LOW LEVEL JET
WILL KICK UP THROUGH THE WESTERN PORTIONS OF THE CWA DURING THE
EVENING...WITH ISENTROPIC LIFT OVERSPREADING THE AREA DURING THE
NIGHT. WITH THIS WILL SEE INCREASING RAIN CHANCES IN OUR WEST IN THE
EVENING...THEN LIFTING NORTHWARD OVERNIGHT. INSTABILITY IS PRETTY
MEAGER SO LOOKING AT ONLY ISOLATED THUNDERSTORMS. SOUTHERLY WINDS
WILL STAY UP OVERNIGHT...AND IT WILL BE MILD WITH LOWS IN THE UPPER
50S TO LOWER 60S.

THE UPPER LEVEL SHORTWAVE SLIDES INTO NEBRASKA AND SOUTH DAKOTA ON
WEDNESDAY...AND WHILE THERE ARE MODEL DIFFERENCES IN CONVECTIVE
TRENDS FOR WEDNESDAY...THE OVERALL THEME LOOKS FOR CONVECTION
THROUGH EASTERN NEBRASKA LATE TUESDAY NIGHT IN ASSOCIATION WITH THE
LOW LEVEL JET TO SLIDE INTO OUR AREA EARLY ON WEDNESDAY. WILL MOST
LIKELY SEE SOME BREAK IN THE ACTIVITY THROUGH MID DAY...BEFORE
PRECIPITATION INCREASES ONCE AGAIN BY LATE AFTERNOON AND ESPECIALLY
INTO WEDNESDAY NIGHT AS THE WAVE FINALLY LIFTS OVER THE AREA AND
FORCING INCREASES. MOISTURE TRANSPORT INTO THE REGION IS PRETTY
STRONG BY WEDNESDAY NIGHT...SO COULD FINALLY GET DECENT RAINFALL
AMOUNTS ACROSS THE AREA.

THE SHORTWAVE BEGINS TO LIFT OUT OF THE REGION ON THURSDAY AS THE
THE SURFACE TROUGH/FRONTAL BOUNDARY SLIDES THROUGH THE AREA. WITH
THIS WILL SEE A GENERAL DOWNWARD TREND IN PRECIPITATION FROM THE
WEST DURING THE DAY. THE BOUNDARY MAY LINGER IN OUR SOUTHEAST ON
THURSDAY NIGHT...KEEPING CONVECTION OVER THAT AREA DURING THAT TIME
FRAME.

MAY FINALLY DRY OUT ON FRIDAY AS HIGH PRESSURE BUILDS INTO THE
REGION. IT LOOKS TO BE A BRIEF BREAK HOWEVER AS AN UPPER LEVEL
TROUGH AGAIN DEEPENS OVER THE WESTERN U.S. AND MOVES EASTWARD FOR
THE WEEKEND...KEEPING UNSETTLED CONDITIONS ACROSS OUR AREA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 643 PM CDT MON MAY 4 2015

MID AND HIGH CLOUDS WILL CONTINUE TO BLANKET THE AREA WITH VFR
CONDITIONS EXPECTED. THE EXCEPTION WILL BE IN THE FAR SOUTH WHERE
LIGHT RAIN SHOWERS OR SPRINKLES WILL PERSIST. AFTER
MIDNIGHT...RAIN CHANCES BEGIN INCREASING IN THE SOUTH WITH SOME
MVFR CEILINGS POSSIBLE FOR KSUX. SCATTERED RAIN SPREADS ACROSS THE
ENTIRE FORECAST AREA AFTER SUNRISE TUESDAY...BUT CHANCES ARE TOO
LOW FOR MENTION IN KFSD AND KHON TAFS.

&&

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

$$

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



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