Area Forecast Discussion
Issued by NWS Sioux Falls, SD

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KFSD 250339
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1039 PM CDT FRI APR 24 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 329 PM CDT FRI APR 24 2015

SHORT TERM CONCERN PRIMARILY THE CONVECTIVE THREAT IN FIRST 6-9
HOURS OF THE FORECAST.

LEADING UPPER WAVE ALMOST EXITING FAR EASTERN CWA...WITH SECONDARY
WAVE PUSHING OUT INTO THE FAR WESTERN PLAINS.  WEAK CONVERGENCE ZONE
HAS MUDDLED ITS WAY INTO THE FAR WESTERN EDGE OF THE FORECAST
AREA... AND HAVE SEEN A COUPLE OF ROGUE STORMS POP UP SOUTH AND WEST
OF KONL. THROUGH THE LATTER AFTERNOON...GENERALLY AGREE WITH VIEW OF
HIGH RESOLUTION SOLUTIONS WHICH INDICATE SPOTTY DEVELOPMENT
GRADUALLY BECOMING MORE EXTENSIVE IN COVERAGE THRU 00Z. WITH
LOCATION WELL NORTH OF THE EVOLUTION OF MAIN UPPER LOW CENTER...FLOW
IN THE MID LEVELS IS QUITE WEAK...SO WEAK THAT DEEP BULK SHEAR IS
NOT SUPPORTIVE OF STORM ORGANIZATION TO ANY DEGREE. GIVEN LIKELIHOOD
OF 600-800 J/KG OF MLCAPE...PROBABLY LOOKING AT A PULSY MULTICELL
TYPE OF ORGANIZATION...WITH VERY SLOW MOVING STORMS FAVORING NEW
DEVELOPMENT ON THE FRINGE OF THE EXPANDING COLD POOLS. IF THERE IS
ANY MARGINAL WIND OR HAIL RISK...LIKELY A 5 TO 8 PM WINDOW WOULD
CAPTURE ANY THREAT ACROSS THE AREAS NEAR THE JAMES RIVER AND
WESTWARD.

FURTHER EAST...LIKELY TO BE VERY LITTLE THREAT WELL THROUGH THE
EVENING...AS ADVECTIVE SPEEDS WILL BE MINIMAL. VERY POSSIBLE THAT
ANY CLUSTER OF PRECIPITATION TO THE WEST WILL FADE PRIOR TO PUSHING
MUCH PAST I 29. MOVING LATER INTO THE NIGHT...AS THE UPPER LOW WRAPS
UP THROUGH THE CENTRAL PLAINS...SOME BETTER DEEP DYNAMICS WRAP UP
TOWARD THE SOUTHEASTERN CWA. LOWER CLOUDS TO THE EAST WILL ALSO BE
THROWN BACK WESTWARD AS EASTERLY FLOW INCREASES...WITH LOWS FAIRLY
MILD IN THE 40S TO AROUND 50.

ON SATURDAY...LINGERING PRECIPITATION THREAT SHOULD BE MAINLY
SOUTH/EASTERN CWA ON NORTHERN EDGE OF FORCING FROM THE UPPER WAVE
AND PRIMARILY EARLY IN THE DAY. WIDE EXPANSE OF LOWER LEVEL RELATIVE
HUMIDITY CONTINUES AT LOW LEVELS ON EASTERLY FLOW...AND SUGGESTION
IN MOST SOLUTIONS IS THAT WILL BE TOUGH TO BREAK LOWER CLOUDS...AT
LEAST UNTIL STRONGER SUBSIDENCE NEAR RIDGE AXIS NOSING IN FROM
NORTHEAST IN THE AFTERNOON. AS A RESULT...TEMPERATURES WILL LARGELY
STRUGGLE...EXPECTING HIGHS IN THE 50S TO AROUND 60...WITH A CLAMMY
EASTERLY WIND.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 329 PM CDT FRI APR 24 2015

FOR SUNDAY AND MONDAY UPPER LEVEL RIDGING BUILDS INTO THE CENTRAL
CONUS...AS SURFACE HIGH PRESSURE BUILDS SOUTHWARD THROUGH THE
NORTHERN MISSISSIPPI VALLEY AND NORTHERN PLAINS. THIS WILL RESULT IN
A GRADUAL DECREASE IN CLOUDS FOR SATURDAY NIGHT INTO SUNDAY.
ALTHOUGH THERMAL PROFILES ON SUNDAY WILL BE SIMILAR TO
SATURDAY...WITH THE EXPECTATION OF MORE SUN ACROSS THE AREA HIGHS
WILL MAKE IT INTO THE LOWER TO MID 60S OVER MOST AREAS. WITH
BUILDING UPPER LEVEL HEIGHTS MONDAY LOOKS TO REMAIN DRY AND A LITTLE
WARMER WITH HIGHS INTO THE MID AND UPPER 60S.

MODELS IN DECENT AGREEMENT ON A SHORTWAVE DIVING INTO THE NORTHERN
PLAINS ON MONDAY NIGHT INTO TUESDAY...THOUGH HAVING MINIMAL IMPACT
ON THE WEATHER AT THIS POINT OTHER THAN TO BRING A SLIGHT CHANCE OF
SHOWERS TO PORTIONS OF OUR AREA ON MONDAY NIGHT. FOR THE REMAINDER
OF THE EXTENDED PERIOD...UPPER LEVEL RIDGING BUILDS BACK INTO THE
REGION WITH DRY CONDITIONS TO PERSIST THROUGH FRIDAY. IN THIS
PATTERN IT DOES LOOK LIKE A WARMING TREND FOR WEDNESDAY INTO
FRIDAY...WITH HIGHS CLIMBING FROM AROUND 70 ON WEDNESDAY TO MID
70S TO NEAR 80 BY FRIDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1035 PM CDT FRI APR 24 2015

WEAK VORTICITY MAX CONTINUES TO ROTATE THROUGH THE CWA LATE THIS
EVENING. AT THE SURFACE...WARM FRONT CONTINUES TO RETREAT
SOUTHWEST ALLOWING COOLER AND MORE STABLE AIR TO FILTER WESTWARD.
HOWEVER...EXPECTING HIT OR MISS SCATTERED SHOWERS AND
THUNDERSTORMS TO CONTINUE TO PERCOLATE THROUGH THE OVERNIGHT
HOURS.

MVFR AND EVENTUALLY IFR CEILINGS WILL SETTLE INTO THE REGION FOR
THE REMAINING OVERNIGHT HOURS AND FIRST HALF OF SATURDAY. AS DRIER
AIR FILTERS IN FROM THE NORTHEAST...WE WILL SEE THESE CEILINGS
IMPROVE TOWARDS MIDDAY.

&&

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

$$

SHORT TERM...CHAPMAN
LONG TERM...JM
AVIATION...DUX


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.