Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 190848
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
348 AM CDT SUN APR 19 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CDT SUN APR 19 2015

UPPER LEVEL LOW CENTERED IN WESTERN KANSAS CONTINUES TO SLOWLY CHURN
EASTWARD WHILE THE DEEP TROUGH RIDING THE NORTHERN STREAM DIGS INTO
NORTHWEST PLAINS. EXPECT THESE TWO FEATURES TO MERGE TODAY AND
SLOWLY SHIFT EASTWARD ACROSS THE PLAINS THROUGH TONIGHT. THE SURFACE
TROUGH WILL LIFT INTO THE GREAT LAKES TODAY AND THE ASSOCIATED COLD
FRONT CURRENTLY HEADING INTO THE I29 CORRIDOR SHOULD CLEAR THE
FORECAST AREA BY MID MORNING. COPIOUS MOISTURE OUT AHEAD OF THE
FRONT IS ALLOWING PATCHY FOG TO DEVELOP...HOWEVER THIS FOG SHOULD
QUICKLY LIFT WITH THE ARRIVING WIND SHIFT. ADDITIONALLY...A FEW
LIGHT RAIN SHOWERS WILL CONTINUE THIS MORNING AHEAD OF THE
FRONT...BUT WILL QUICKLY DIMINISH IN ITS WAKE. NORTHWEST WINDS WILL
BECOME QUITE BREEZY...REACHING JUST SHY OF WIND ADVISORY LEVELS WEST
OF THE JAMES RIVER. WILL GO WITH 20 TO 30 MPH WINDS WITH GUSTS TO 40
MPH HERE AND 15 TO 30 MPH ELSEWHERE. CLOUDY SKIES WILL HOLD ON THIS
MORNING THEN BECOME SCATTERED FROM WEST TO EAST THIS AFTERNOON AND
EARLY EVENING. HIGHS TODAY WILL BE SLIGHTLY COOLER THAN NORMAL IN
THE MID 50S TO NEAR 60.

WINDS WILL DECREASE THIS EVENING BUT WILL REMAIN SOMEWHAT BREEZY
OVERNIGHT AROUND 15 TO 20 MPH. WITH CLEARING SKIES AND A COOL
AIRMASS ARRIVING...LOWS WILL BE QUITE A BIT COOLER. WENT WITH MIDDLE
GROUND CONSALL GUIDANCE WITH LOWS IN THE MID TO UPPER 30S.


.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 348 AM CDT SUN APR 19 2015

MONDAY WILL BE QUITE WINDY WITH THE AIR VERY UNSTABLE UP TO MID
LEVELS. MOISTURE LOOKS GOOD ENOUGH TO KEEP COUNTING ON SHOWER
DEVELOPMENT AT LEAST NORTH THROUGH EAST OF FSD. IN FACT CONSIDERED
RAISING POPS AND PULLING THE MENTION SOMEWHAT FURTHER SOUTHWEST BUT
IT IS TRUE THAT THE AIR BECOMES STEADILY DRIER AS ONE GOES NORTHEAST
TO SOUTHWEST OVER THE CWA...AND AFTER COORDINATION HAVE LEFT THE
MENTION PRETTY MUCH WHERE IT WAS IN THE EARLIER FORECAST. THE
INSTABILITY DOES NOT GO UP REAL HIGH SO WE ARE NOT LOOKING AT
THUNDER OR VERY MUCH IN THE WAY OF RAINFALL AMOUNTS. TEMPERATURES
MONDAY WILL BE COOL...SLIGHTLY LESS COOL THAN WE HAD BEFORE IN THE
VERY MIXED LOW LEVELS...BUT THE STRONG WINDS WILL ADD A COOL TOUCH.
A WIND ADVISORY MAY BE NEEDED THOUGH FOR NOW HAVE KEPT THE WINDS
JUST A LITTLE ABOVE GUIDANCE AND JUST BELOW THE ADVISORY LEVEL.

AFTER LOW TEMPERATURES CLOSE TO FREEZING MONDAY NIGHT...TUESDAY WILL
BE LESS WINDY AND A COUPLE DEGREES WARMER THAN MONDAY. A WEAK WAVE
ON THE WEST SIDE OF THE DIGGING TROUGH WILL BRING A MINOR SECONDARY
SURGE OF COOL AIR BY TUESDAY NIGHT. THE GFS IS STRONGER WITH THIS
WAVE THAN THE NAM AND BRINGS QUITE A BIT OF MID LEVEL MOISTURE/
CLOUDS OVER THE AREA TUESDAY...THOUGH WITH THE DRIER LOW LEVELS IT
DOES NOT KICK OUT PRECIPITATION. THE NAM AND EC SUGGEST MORE PATCHY
CLOUDS. WILL KEEP THE FORECAST DRY AND THE CLOUD COVER MODEST FOR
NOW.

WEDNESDAY AND THURSDAY LOOK DRY AND COOL WITH 50S HIGHS AND FREEZING
LOWS...STILL BEING APRIL NO FROST FREEZE HIGHLIGHTS YET. FRIDAY AND
SATURDAY LOOK TO BRING A SLIGHT WARMUP BUT WITH THE USUAL MODEL
DIFFERENCES ON LIGHT SHOWER THREATS. WILL ADVANCE A SMALL CHANCE OF
SHOWERS EAST ACROSS THE AREA DURING THESE DAYS. THE GFS SOLUTION IS
RIDGING OVER THE AREA FROM THE NORTH/EAST BLOCKING MOST OF THE
MOISTURE SPREAD WHILE THE EC SHOWS BETTER MOISTURE INFLOW TO THE
NORTH OF THE UPPER LOW COMING INTO THE SOUTHERN AND CENTRAL PLAINS.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1048 PM CDT SAT APR 18 2015

CONFIDENCE IS FAIRLY LOW FOR THE 06Z TAFS IN THE NEAR TERM WITH A
TROUBLESOME SCENARIO PRIMARILY WITH THE CEILINGS. IFR CONDITIONS
COULD BE PRESENT IN OUR FAR WEST AND NORTHWEST ZONES FOR THE NEXT
FEW HOURS AS LIGHT RAIN OR DRIZZLE LOWERS VISIBILITIES. THIS WAS
ACCOUNTED FOR IN THE KHON TAF SITE...HOWEVER IT NEEDS TO BE NOTED
THAT THESE CONDITIONS MAY NOT PREVAIL ALL THE TIME...THUS THE
TEMPO GROUP. THE WIND SHIFT TO THE NORTHWEST WILL THEN MAKE IT TO
KHON AROUND 08Z WHICH SHOULD BEGIN TO IMPROVE THEIR VISIBILITY AND
ALSO GIVE A SLOW RISE TO THE CEILINGS...LEADING INTO A WINDY DAY
ON SUNDAY WITH VFR CONDITIONS BY LATE MORNING.

SPOTTY IFR CEILINGS ALSO CURRENTLY EXIST AROUND KFSD BUT UPSTREAM
OBSERVATIONS IN NORTHWEST IA ARE PRIMARILY MVFR TO VFR. SO THIS IS
QUITE A CHALLENGE. DECIDED TO RAISE THE IFR CEILINGS TO MVFR BY
LATE TONIGHT JUST AHEAD OF THE WIND SHIFT AS LOW LEVEL WINDS VEER
MORE TO A SOUTH TO SOUTHWEST DIRECTION WHERE CEILINGS ARE HIGHER.
SIMILAR TO KHON...AFTER THE WIND SHIFT HITS KFSD THE CEILINGS
SHOULD BEGIN A SLOW RISE TOWARD VFR. KSUX IS CURRENTLY VFR AS A
DRY SLOT HAS IMPACTED THEM OOZING UP FROM EASTERN NEBRASKA. IT
COULD BE POSSIBLE THAT SOME LOWERED CEILINGS IN THE MVFR RANGE
COULD AFFECT KSUX JUST BEHIND THE WIND SHIFT.


&&

.FIRE WEATHER...
ISSUED AT 348 AM CDT SUN APR 19 2015

RAINFALL AMOUNTS YESTERDAY SEEM TO BE TOO LIGHT TO DENT THE VERY
HIGH FIRE DANGER FOR OUR NORTHWESTERN HALF OF THE CWA. BETTER
RAINFALL SHOULD KEEP THE INDEX TO MODERATE IN NORTHWEST IOWA
ESPECIALLY GIVEN THE LATER WIND INCREASE. WITH THE DRYING POWER OF
TODAYS WIND HAVE KEPT THE OUTPUT AS VERY HIGH TO HIGH MONDAY AND
TUESDAY...WITH MONDAY THE WORST DAY. HUMIDITY TOO HIGH FOR RED
FLAG CONSIDERATION TODAY. MONDAY IS NOT OUT OF THE QUESTION WEST
BUT WILL NOT ISSUE A WATCH FOR NOW.

&&

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

$$

SHORT TERM...
LONG TERM...
AVIATION...MJ
FIRE WEATHER...


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