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000
FXUS63 KFSD 222346
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
646 PM CDT TUE JUL 22 2014

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 300 PM CDT TUE JUL 22 2014

WILL GO AHEAD AND KEEP THE MENTION OF ISOLATED TO SCATTERED
CONVECTION GOING INTO THE VERY EARLY EVENING HOURS ACROSS OUR FAR
SOUTHERN ZONES...INCLUDING THE SIOUX CITY AREA. THIS ACTIVITY
DEVELOPED EARLIER THIS AFTERNOON TOWARD NORTH CENTRAL NEB ALONG MID
LEVEL CONVERGENCE WHICH HAS SINCE WANED. HOWEVER A STRONG 850MB
FRONTAL BOUNDARY IS POSITIONED IN OUR FAR SOUTH LATE THIS AFTERNOON
WHICH WILL LIKELY HELP TO KEEP THE ACTIVITY GOING. OTHERWISE IT
SHOULD BE DRY TONIGHT AS SURFACE HIGH PRESSURE USHERS IN EVER
INCREASING DRIER AIR FROM THE NORTH. ANY CONVECTIVE CHANCES TONIGHT
SHOULD STAY WEST OF OUR FORECAST AREA TONIGHT. IF CONVECTION DOES
DEVELOP IN THE WESTERN PLAINS...AM PROBABLY A LITTLE THIN ON THE SKY
COVER TONIGHT AS CIRRUS WILL THEN MOVE ACROSS THE FORECAST AREA.
925MB TEMPERATURES HAVE NOT CHANGED MUCH FROM MODEL RUN TO RUN...SO
DID NOT HAVE TO ALTER LOWS MUCH AT ALL.

COULD BE SOME MID CLOUDS IN OUR WESTERN ZONES WEDNESDAY MORNING. BUT
OTHERWISE KEPT THINGS DRY WITH A SEASONABLY MILD DAY IN THE UPPER
70S TO MID 80S.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 PM CDT TUE JUL 22 2014

WEDNESDAY NIGHT WILL SEE THE WARM ADVECTION PATTERN AND THE
POTENTIAL FOR THERMAL LIFT RELATED CONVECTION...AT LEAST IN OUR SD
AREA. THIS PATTERN WILL DEVELOP AS THE STRONG PACIFIC WAVE EATS INTO
THE UPPER RIDGE. MOISTURE AND ESPECIALLY INSTABILITY WILL BE SLOW TO
RETURN...BUT THE THREAT SHOULD REACH INTERSTATE 29 BY DAYBREAK
THURSDAY...CONTINUE OVER THE AREA THURSDAY AND BECOME ENHANCED
SOME...ESPECIALLY EASY...THURSDAY NIGHT INTO FRIDAY AS THE STRONG
RIDGE FLATTENING WAVE APPROACHES. SATURDAY SHOULD THEN BE DRY.
MODESTLY COOL TEMPERATURES WILL WARM SOMEWHAT THROUGH FRIDAY THEN
SHOULD STILL BE MILD SATURDAY ESPECIALLY WITH MORE SUNSHINE. OF
COURSE WITH THE MAIN UPPER RIDGE FORCED BACK WELL SOUTHEAST OF THE
NORTHERN PLAINS...THE HOT AND STICKY AIR OF YESTERDAY WILL NOT MAKE
IT BACK.

SUNDAY WILL BRING THE PASSAGE OF A SECONDARY WAVE BRINGING COOLER
AIR AND SOME FAIRLY SMALL CHANCE OF SHOWERS OR STORMS NORTHEAST AS A
POCKET OF EVEN COOLER AIR ALOFT PASSES BY. THIS SECOND WAVE WILL
THEN HELP DIG A LARGE SCALE TROUGH OVER THE GREAT LAKES AND EASTERN
USA AND LEAVE OUR AREA IN A DRY AND MODESTLY COOL NORTHERLY FLOW
EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 645 PM CDT TUE JUL 22 2014

VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.

&&

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

$$

SHORT TERM...MJ/
LONG TERM...
AVIATION...