Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 191106
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
606 AM CDT SAT JUL 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 307 AM  CDT SAT JUL 19 2014

WARMER AIR BEGINS TO MAKE A PUSH INTO THE FORECAST AREA TODAY...
ESPECIALLY WEST WHERE A FEW LOCATIONS COULD APPROACH 90 DEGREES.
THESE AREAS COULD SEE FAIR AMOUNT OF HIGH LEVEL CLOUD COVER EARLY
THIS MORNING WITH BLOW-OFF FROM WEAKENING STORMS IN WESTERN SD...
BUT ANTICIPATE THIS WILL GIVE WAY TO MORE SUNSHINE BY MIDDAY AND
ALLOW FOR STRONG WARMING AS LOW LEVEL THERMAL RIDGE WORKS EAST.
CONVECTIVE CHANCES REMAIN QUITE SPOTTY THROUGH THE NEXT 24 HOURS.
EXPECT WESTERN SD ACTIVITY TO DIMINISH BEFORE REACHING OUR FAR
WESTERN AREAS THIS MORNING...BUT WILL HAVE TO WATCH SMALL AREA OF
STORMS IN WEST CENTRAL MN. HAVE BEEN SEEING ACCAS DEVELOPMENT EXPAND
WESTWARD INTO OUR FAR NORTHERN COUNTIES THROUGH THESE EARLY MORNING
HOURS...AND MANY HIGH-RES MODELS SHOW THIS ACTIVITY EXPANDING INTO
SOUTHWEST MINNESOTA THROUGH MID-LATE MORNING AS TAIL END OF WEAK MID
LEVEL WAVE SLIPS SOUTHEAST...BEFORE WEAKENING TOWARD MIDDAY. HARD TO
ARGUE WITH THIS SCENARIO GIVEN PRESENT SOUTHWARD MOVEMENT INTO EARLY
MORNING 30-40KT LOW LEVEL JET...FOLLOWED BY WEAKENING AS LOW LEVEL
JET UNDERGOES DIURNAL DOWNWARD TREND.

EXPECT DRY CONDITIONS THE REMAINDER OF THE DAY AND THROUGH THE
EVENING...BUT ISOLATED STORMS BECOME POSSIBLE AGAIN ACROSS OUR WEST
LATER TONIGHT AS ANOTHER WEAK WAVE SLIDES EAST THROUGH THE REGION.
DEVELOPMENT TONIGHT CERTAINLY NO GUARANTEE AS SOME MODEL SOUNDINGS
SHOW FAIRLY STOUT CAP EVEN TO ELEVATED CONVECTION...BUT WITH THE
SUBTLE WAVE AND STEEPENING MID LEVEL LAPSE RATES...FEEL IT IS WORTH
CARRYING A SMALL POP DURING THE LATTER PART OF THE NIGHT.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 307 AM  CDT SAT JUL 19 2014

FORECAST FOCUS IN THE LONG TERM IS ON HOT TEMPERATURES SUNDAY AND
MONDAY ALONG WITH WITH THE POTENTIAL FOR THUNDERSTORM ACTIVITY MONDAY
AND MONDAY NIGHT.

SUNDAY...VERY WARM AND MOIST AIR WILL CONTINUE TO ADVECT NORTHEAST
INTO THE REGION ON SUNDAY. MODEL GUIDANCE CONTINUES TO HINT AT
WIDELY SCATTERED SHOWERS/STORMS INTO EARLY SUNDAY MORNING AS NOSE OF
STOUT EML ADVECTS INTO THE AREA. MOST OF THE AREA SHOULD REMAIN
DRY...AND HAVE CONFINED POPS TO THE EASTERN CWA IN THE MORNING
HOURS. BY THE AFTERNOON...850MB TEMPS WILL CLIMB BETWEEN +24C AND
+28C.  THIS WILL RESULT IN AFTERNOON TEMPERATURES APPROACHING MID
90S WEST OF THE JAMES RIVER...TO THE UPPER 80S IN AREAS EAST.  THE
COMBINATION OF EVAPOTRANSPIRATION AND BOUNDARY LAYER MOISTURE
ADVECTION WILL PUSH AFTERNOON DEW POINTS INTO THE LOWER 70S.
RESULTANT HEAT INDEX VALUES WILL PUSH ADVISORY CRITERIA IN AREAS
PRIMARILY WEST OF THE JAMES RIVER.

MONDAY...A STATIONARY BOUNDARY IS EXPECTED TO DEVELOP AND SPRAWL
ACROSS CENTRAL SD INTO EASTERN ND BY MONDAY MORNING. AN INTENSIFYING
MID-LEVEL RIDGE CENTERED OVER THE FOUR CORNERS REGION WILL LIFT
A MID-LEVEL DISTURBANCE CURRENTLY OVER SOCAL ACROSS THE CENTRAL
ROCKIES AND INTO THE NORTHERN PLAINS BY MONDAY NIGHT. AT THE
SURFACE...CYCLOGENESIS WILL LIKELY OCCUR OVER WESTERN SD AND RIDE
NORTHEAST ALONG THE STALLED BOUNDARY MONDAY NIGHT...NOT ONLY
ENHANCING MOISTURE TRANSPORT INTO THE REGION...BUT ALSO FORCING
WARMER READINGS EASTWARD.  CURRENT FORECAST SUGGESTS HEAT ADVISORY
CRITERIA OVER THE MAJORITY OF THE CWA...AND PORTIONS OF THE WESTERN
ZONES MAY BRIEFLY REACH EXCESSIVE HEAT WARNING CRITERIA.

CHANCES FOR CONVECTION INCREASE BY LATE MONDAY AFTERNOON AND
CONTINUE MONDAY NIGHT.  SOUNDINGS ACROSS THE CWA INDICATE A STOUT
CAP IN PLACE...WITH 700MB TEMPS AOA +14C. HIGHEST CHANCES FOR
DEVELOPMENT WILL OCCUR ALONG AND NORTH OF THE STATIONARY BOUNDARY AND
IN VICINITY OF STRONGEST LOW-LVL CONVERGENCE NEAR THE SURFACE LOW
AND MAXIMIZED AREA OF LARGE SCALE ASCENT ACROSS THE NORTHERN
PORTIONS OF SOUTH DAKOTA...WHICH COULD CLIP THE FAR NORTHWESTERN
CWA. CONVECTION...ONCE FORMED...WILL BE ABLE TO TAP INTO AN EXTREME
AMOUNT OF INSTABILITY WITH A POTENTIAL FORWARD PROPAGATING MCS MOVING JUST
NORTH OF THE CWA MONDAY NIGHT.

TUESDAY...THE MID-LVL RIDGE WILL PEAK ACROSS THE ROCKIES ON
TUESDAY...INDUCING A BRIEF PERIOD OF NW FLOW AND SLIGHTLY COOLER AND
DRY WEATHER FOR TUESDAY AND WEDNESDAY. A WEAK SECONDARY SHORTWAVE
WILL RACE IN QUICKLY BEHIND THE DEPARTING WAVE FROM MONDAY NIGHT.
THIS WAVE COULD BRING A FEW SHOWERS TO CENTRAL SD TUESDAY.  MODELS
ARE CONSISTENT IN BRINGING ENERGY OVER BRITISH COLUMBIA EASTWARD BY
THURSDAY WHICH WILL BRING INCREASED RAIN CHANCES AT THAT TIME.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 606 AM CDT SAT JUL 19 2014

SPOTTY THUNDERSTORM CHANCES AROUND THE AERA THIS MORNING...AND AGAIN
AFTER 20/05Z...MAINLY AFFECTING OUR SD/MN COUNTIES. HOWEVER...WITH
ISOLATED NATURE OF ANY EXPECTED STORMS...CHANCE AT SPECIFIC POINT
TOO LOW TO MENTION IN TAFS AT THIS TIME. EXPECT VFR CONDITIONS TO
PREVAIL...THOUGH THE ISOLATED STORMS COULD BRING BRIEF REDUCTION TO
MVFR CONDITIONS. WEAK SURFACE BOUNDARY SAGGING INTO NORTHWEST PARTS
OF THE FORECAST AREA WILL BRING SOME VARIABILITY TO WINDS AT OR BELOW
10KTS IN THOSE AREAS TODAY...WITH STRONGER WINDS OCCASIONALLY GUSTING
INTO 20-25KT RANGE CONFINED MAINLY ALONG/SOUTHEAST OF HIGHWAY 60 IN
NORTHWEST IA AND SOUTHWEST MN.

&&

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

$$

SHORT TERM...JH
LONG TERM...DUX
AVIATION...JH







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