Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 241951
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
251 PM CDT THU JUL 24 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 251 PM CDT THU JUL 24 2014

FAVORABLE PATTERN FOR STORMS WILL CONTINUE TO SHIFT SLOWLY EAST
TONIGHT...INCLUDING WIND FIELDS AND RESULTING THETA E ADVECTION.
CURRENT STORMS WILL LIKELY CONTINUE MOVING OVER EASTERN PART OF THE
AREA...FROM NORTH OF FSD AND OVER SOUTHWEST MN AND NORTHWEST IA THE
REST OF THIS AFTN. STORMS SHOULD DECREASE OR BRIEFLY END EARLY THIS
EVENING BEFORE SOME REDEVELOPMENT AS LOW LEVEL JET KICKS IN. THIS
DEVELOPMENT COULD GET BACK CLOSE TO FSD THOUGH WILL KEEP POPS HERE
JUST AT SLIGHT CHANCE FOR NOW. ISOLATED STORMS STILL SEEM POSSIBLE
FURTHER WEST AS INCREASING INSTABILITY AND MOISTURE FIGHT A
CAP...THOUGH WITH THAT LLJ SHIFTING EAST AM TEMPED TO DROP.

STORMS SHOULD DEFINITELY DECREASE OVER OUR EASTERN AREA LATE TONIGHT
AND ANY ISOLATED STORMS WILL QUICKLY END WEST. THE SOUTHERLY WARMING
PATTERN SHOULD HOLD LOW TEMPERATURES IN THE MID TO UPPER 60S.

THERMAL AND WIND PATTERNS FAVORABLE FOR STORMS WILL CONTINUE TO
SHIFT EAST OF THE AREA EARLY FRIDAY AS LOW PRESSURE EXITS THE AREA
WITH THE FLOW BECOMING VERY WEAK NORTH OF THE LOW. WILL KEEP ONLY A
SMALL MENTION FAR EAST EARLY OTHERWISE IT LOOKS DRY. FAIRLY WARM
TEMPERATURES IN THE 80S WITH AROUND 90 ALONG THE MISSOURI RIVER
AREA.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 251 PM CDT THU JUL 24 2014

A WEAK SHORT WAVE PASSING OVER THE AREA FRIDAY NIGHT INTO SATURDAY
MAY TAKE ADVANTAGE OF A FAIRLY TIGHT THERMAL GRADIENT SOUTH OF
DIGGING CANADIAN UPPER LOW TO PRODUCE A FEW STORMS OVER THE
SOUTHWEST PART OF THE AREA AND ALONG THE MISSOURI RIVER TO THE SIOUX
CITY AREA. WILL MENTION AS SLIGHT CHANCE TO LOW CHANCE POPS MAINLY
LATE FRIDAY NIGHT AND EARLY SATURDAY...KEEPING DRY IN THE NORTH.
TEMPERATURES WILL SHOW SOME SLIGHT COOLING SATURDAY BUT WILL STILL
BE MILD. ANY STORMS FAR SOUTH SHOULD END BY THE END OF THE DAY AS
MORE STABLE AIR SETS IN.

THE CANADIAN UPPER LOW WILL PASS SOUTHEAST ACROSS THE FAR WESTERN
GREAT LAKES LATE SATURDAY NIGHT AND SUNDAY AND BRING COOLING. WILL
KEEP A FEW SHOWERS NORTHEAST SUNDAY GIVEN THE COOLING ALOFT BEING
STRONGER THAN AT LOWER LEVELS.

MONDAY THROUGH THURSDAY LOOK GENERALLY DRY AS THE CANADIAN LOW DIGS
A BROAD UPPER TROUGH EAST OF THE AREA. EXTENDED GUIDANCE KEEPS A
SLIGHT CHANCE OF SHOWERS OR STORMS NEAR THE END OF THE PERIOD AND
WILL KEEP IN GIVEN THE MODELS ARE STILL SHOWING A NORTHWESTERLY
SHORT WAVE PASSING ON THE WEST SIDE OF THE TROUGH. THIS FEATURE
LOOKS QUITE WEAK AND HARD TO TIME AND AM TEMPTED TO KEEP THE
FORECAST DRY THROUGH THE EXTENDED PERIOD. HOWEVER WE ARE ALMOST
DOING THAT ANYWAY GIVEN THE LOW POPS. TEMPERATURES SHOULD BE QUITE
MILD...THAT IS BELOW NORMAL...WITH AT MOST WEAK WARMING GIVEN THE
ANCHORED NATURE OF THE LARGE SCALE PATTER WITH THE RIDGE TO THE
WEST AND TROUGH TO THE EAST. BEYOND THE FORECAST PERIOD...THE GFS
AND EC BOTH SUGGEST WARMING IN SLIGHTLY DIFFERENT WAYS...THE GFS
WITH A BUILDING OF THE RIDGE INTO THE PLAINS...AND THE EC WITH A
FLATTENING OF THE UPPER FLOW SOUTH OF A HUGE DEVELOPING HUDSON BAY
UPPER LOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1220 PM CDT THU JUL 24 2014

OVERALL...VFR WILL PREVAIL FOR MOST AREAS THROUGH THE TAF PERIOD
ENDING AT 18Z FRIDAY. BUT THUNDERSTORMS MOVING SOUTHEASTWARD
ACROSS AREAS EAST OF THE JAMES RIVER VALLEY WILL CERTAINLY NEED
WATCHED INTO LATE THIS AFTEROON AND EVENING...AS A STOUT LOW LEVEL
JET REMAINS JUXTAPOSED RIGHT IN THIS AREA. THIS WILL GIVE THE
POSSIBILITY OF CONTINUED SCATTERED REDEVELOPMENT. FOR NOW...THIS
IS VERY DIFFICULT TO TIME SO LEFT OUT OF THE THREE TAF SITES THE
MENTION OF TSRA. KFSD MAY BE THE MOST IMPACTED BY THIS SCENARIO SO
DO NOT BE SURPRISED IF YOU SEE AMENDMENTS INVOLVING CONVECTION.
BUT ALSO NEED TO KEEP A CLOSE EYE ON KSUX FOR REDEVELOPMENT BUT
MUCH OF THEIR ACTIVITY MAY STAY TO THE NORTH AND EAST. KHON MAY
ALSO SEE MOST OF THEIR ACTIVITY OFF TO THE EAST. SO MOST CONCERNED
ABOUT KFSD THROUGH THE EVENING. IN ANY STRONG STORMS...BRIEF HAIL
AND MVFR CONDITIONS ARE POSSIBLE. LATE TONIGHT AND FRIDAY
MORNING...IT IS EXPECTED THAT THE CONVECTION WILL STAY NORTH OF
OUR AREA. CONCERNING WINDS...EXPECT FREQUENT GUSTS FROM THE SOUTH
AND SOUTHEAST ALONG AND EAST OF THE JAMES RIVER VALLEY THIS
AFTERNOON OF AROUND 25 TO 30 KNOTS. FURTHERMORE...A STRONG LOW
LEVEL JET WILL EXIST FOR MUCH OF THE AREA TONIGHT...SOME OF WHICH WILL
TRANSLATE DOWN TO THE SURFACE. BUT FOR NOW LEFT THE MENTION OF NON
CONVECTIVE LOW LEVEL WIND SHEAR OUT OF THE TAFS BECAUSE SURFACE
SPEEDS MAY BE STRONG ENOUGH TO PRECLUDE THE MENTION OF IT.


&&

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

$$

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





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