000
FXUS63 KFSD 251139
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
639 AM CDT SAT MAY 25 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT SAT MAY 25 2013

THUNDERSTORM COMPLEX OVER NEBRASKA OVERNIGHT CONTINUES EARLY THIS
MORNING. SEEING SHOWERS AND STORMS BEGINNING TO EXPAND ACROSS
NORTHWEST IOWA AS WELL AS LOW LEVEL THETAE ADVECTION INCREASES. HIGH
RES MODEL SUITE LOOK TO HAVE A PRETTY GOOD HANDLE ON THIS ACTIVITY.
EXPECT IT TO CONTINUE THIS MORNING AND POSSIBLY EXPAND A BIT FURTHER
NORTH INTO PORTIONS OF SOUTHWEST MINNESOTA. LOWERED POPS ACROSS
SOUTHEAST SOUTH DAKOTA...AS ALL INDICATIONS ARE THAT THESE STORMS
WILL NOT DEVELOP NORTHWEST OF THEIR CURRENT LOCATION. MOST OF THE
STORMS SHOULD BE EAST OF THE CWA BY 16Z. MAIN IMPACTS WILL BE
BRIEFLY HEAVY RAIN AND POSSIBLY SMALL HAIL WITH THESE CELLS...AS
EFFECTIVE SHEAR AND CAPE ARE TOO LOW FOR ANY SEVERE THREAT. MUCH OF
THE AFTERNOON SHOULD THEN BE DRY ACROSS THE CWA WITH AN AREA OF
SUBSIDENCE LIKELY BEHIND THIS MORNINGS SHORTWAVE. WARM FRONTAL
BOUNDARY WILL POSITION ITSELF SOUTH OF THE MISSOURI RIVER THIS
AFTERNOON. HRRR AND RAP TRY TO BREAK THE CAP THEIR THIS
AFTERNOON...BUT BOTH THESE MODELS SEEM A BIT OVERDONE WITH DEWPOINTS
AND INSTABILITY. FEEL MORE LIKELY SCENARIO IS ACTIVITY WAITS FOR THE
LOW LEVEL JET TO KICK IN AFTER 0Z BEFORE IT GETS GOING.

OTHER ISSUE TODAY IS CLOUD COVER AND HIGH TEMPERATURES.
INTERESTINGLY THE HRRR AND RAP ARE COMPLETE OPPOSITE OF EACH
OTHER...GIVING AROUND A 20 DEGREE DIFFERENCE IN HIGHS...WITH THE RAP
HAVING MORE STRATUS AND COOLER TEMPERATURES. THE GEM AND ECMWF SIDE
CLOSER TO THE RAP...WITH THE NAM IN BETWEEN. SINCE THE AREAL
COVERAGE OF LOW STRATUS IS CURRENTLY LESS THAN EXPECTED...DID GO
AHEAD AND RAISE HIGHS SEVERAL DEGREES FOR TODAY IN OUR CENTRAL AND
WEST. ALSO THE HRRR HAS A GOOD HANDLE ON THE CURRENT SITUATION...SO
ONE WOULD THINK ITS SHORT RANGE FORECAST SHOULD BE SOMEWHAT
RELIABLE...AND IT HAS CONSISTENTLY BEEN WARM FOR TODAY. LOWERED
HIGHS A FEW IN THE EAST WHERE IT IS RAINING...AND WHERE STRATUS
SHOULD INDEED HOLD IN FOR MUCH OF THE DAY. AGAIN THIS IS A PRETTY
LOW CONFIDENCE TEMPERATURE FORECAST FOR ANYWHERE EAST OF THE JAMES
RIVER. BUT FEEL GOING FORECAST IS A DECENT STARTING POINT...WITH THE
DAY SHIFT LIKELY HAVING TO ADJUST UP OR DOWN DEPENDING ON CLOUD
COVER TRENDS.

QUIET SHORT TERM CONDITIONS FROM THE AFTERNOON HOURS SHOULD TURN
QUICKLY TO MORE STORMY CONDITIONS OVERNIGHT. GAVE A FAIR AMOUNT
OF CREDIT TO THE CONSISTENCY OF THE 00Z HIGH RESOLUTION NAMDNG5
AND WRF-ARW SOLUTIONS...WHICH FIT THE OVERALL CONCEPTUAL MODEL FOR
CONVECTIVE INITIATION TONIGHT. BOUNDARY FROM CURRENT NIGHT MCS
WILL BE FESTERING AND DRIFTING NORTHWARD...WITH LIKELY 1000 TO
1500 J/KG ELEVATED CAPE LIFTED FROM 1 TO 1.5 KM AGL. AS 35 TO 40
KNOT LOW LEVEL JET DEVELOPS TONIGHT THROUGH THE CENTRAL PLAINS...
SHOULD BECOME ENOUGH TO INITIATE ELEVATED THUNDERSTORMS NEAR/NORTH
OF THE BOUNDARY WHICH WILL BE DRIFTING NORTHWARD OF INTERSTATE 80
DURING THE EVENING HOURS. EFFECTIVE SHEAR IN AREAS NORTH OF THE
BOUNDARY WILL BE VERY CONCENTRATED IN THE 1-3KM LAYER WITH STRONGEST
WINDS IN LOW LEVELS AND WEAKENING MID LEVEL WINDS ROUGHLY 20-30
KNOTS...WITH LESSER DEEP LAYER SHEAR CONTRIBUTIONS FROM ABOVE. ALL
SUGGEST AT LEAST A MINIMAL THREAT FOR ISOLATED LARGER HAIL OR
DAMAGING WINDS THROUGH THE MISSOURI RIVER CORRIDOR AND LIFTING
SOMEWHAT NORTHWARD THROUGH 066-08Z. OTHER SIGNIFICANT CONVECTIVE
INITIATION IS LIKELY TO OCCUR BACK THROUGH THE WESTERN HIGH PLAINS
WHERE STRONGER SHEAR EXISTS WITH A BIT STRONGER MID LEVEL WINDS
TO AROUND 25 KNOTS...AS WELL AS THE DEEP UPSLOPE TRANSPORT OF MOISTURE
TO RESULT IN STRONGER INSTABILITY. EVENTUALLY...WHEN SUPERCELL MOTIONS
WHICH WILL TAKE ACTION MORE SOUTHWARD THAN EAST START TO EASE...AND
LOW LEVEL JET VEERS EASTWARD...WILL FIND A MORE LINEAR MCS LIKELY
TAKING SHAPE. MANY HI RES MODELS SUGGEST THIS MCS WILL ZIPPER DOWN
THE LOCATION OF THE WARM ADVECTION WING SPREADING NORTHWARD...MOVING
TOWARD EAST CENTRAL SD AND SOUTHWEST MN LATE NIGHT. SEVERE THREAT
WITH THIS FEATURE WOULD SEEM TO BE SOMEWHAT LOWER...BUT LIKELY TO
GET SOME GUSTY WINDS AND AREAS OF HEAVY RAINFALL.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 430 AM CDT SAT MAY 25 2013

MCS EXPECTED TO WEAKEN AND SHIFT EAST ON SUNDAY...AND WITH MID
LEVEL FORCING SHOWING TENDENCY TO FORCE SUBSIDENCE AROUND
MIDDAY...AGAIN EXPECT THAT MUCH OF THE DAYTIME PERIOD WILL
PROBABLY END UP PRECIPITATION FREE. HOWEVER...CLOUDS LIKELY TO
PERSIST WITH STRATUS DEVELOPING IN WAKE OF SYSTEM. MOST LIKELY TO
GET BREAKS THROUGH THE WESTERN AND SOUTHERN CWA DURING THE
AFTERNOON...AND HAVE PUSHED EXPECTED TEMPS TO NEAR 80 THERE...
WHILE MORE MID TO UPPER 60S LINGER IN THE FAR EAST. RESULT OF THIS
WILL BE GENERATION OF DECENT POTENTIAL INSTABILITY OF 1500-2000
J/KG ACROSS THE AREA...WITH WEAKEST OF THE CAPPING INVERSION NEAR
THE MISSOURI RIVER CORRIDOR. SHEAR BECOMES A BIT MORE DISTRIBUTED
THROUGH THE EFFECTIVE LAYER...AND FAIRLY CLOSE TO THOSE VALUES
FROM THIS EVENING FROM 30 TO 35 KNOTS. A FEW MORE SEVERE STORMS
WOULD BE POSSIBLE MAINLY THROUGH THE SOUTHWEST HALF OF THE AREA
DURING THE LATER AFTERNOON AND EVENING HOURS...AS INITIATION
LIKELY TO BE A RESULT OF WEAK IMPULSE SLIDING UP BACK SIDE OF
RIDGE IN THE LATER AFTERNOON AND EARLY EVENING.

THE FURTHER ONE GOES INTO THE FORECAST...THE LESS RELIABLE ANY
GUIDANCE BECOMES GIVEN THE ABUNDANCE OF CONVECTION...AND THE
INCREASINGLY GREAT UNCERTAINTY AS TO WHERE CRITICAL BOUNDARIES MAY
LIE. ONE THING FOR SURE...GIVEN THE CLOSED LOW ACROSS THE WESTERN
U.S. AND THE SOUTHWEST FLOW ALOFT...DIFFICULT TO PINPOINT ANY TIME
FROM MONDAY ON THAT ONE COULD SAY THERE WAS ABSOLUTELY NO CHANCE
FOR PRECIPITATION...BUT ON THE SAME FRONT IT CERTAINLY WILL NOT BE
AN ALL TIME WASHOUT WITH MANY BREAKS DEFINED ON THE MESOSCALE.
MEMORIAL DAY AND MONDAY NIGHT WILL PLACE THE AREA ON THE SOUTHERN
FLANK OF A COUPLE OF WAVES MOVING OVER THE RIDGE...SO LIKELY TO
HAVE ENHANCEMENT OF PRECIPITATION IN THE NOCTURNALLY FAVORED
PERIODS. WHILE A FEW SEVERE STORMS ARE AGAIN WELL WITHIN
REASON...HIGH PRECIPITABLE WATER AND FAIRLY SLOW MOVING WIND
PROFILES BRING THE CONCERN OF AREAS OF HEAVY RAINFALL...AT THIS
RANGE HARD TO DEFINE. AT THE MOMENT...THE PROSPECT FOR MORE
SIGNIFICANT CONVECTION AND SEVERE WEATHER WOULD APPEAR TO BE LATE
DAY WEDNESDAY INTO THURSDAY...AS DEEP WESTERN CLOSED LOW KICKS
STRONGER JET ENERGY INTO THE PLAINS. MOISTURE THROUGH LOWER LEVELS
/THUS INSTABILITY/ WILL CONTINUE TO BENEFIT FROM PERSISTENT
SOUTHERLY FLOW. TEMPERATURES WILL LIKELY GRAVITATE TO SOMEWHAT
ABOVE NORMAL READINGS THROUGH THE UPCOMING WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 619 AM CDT SAT MAY 25 2013

LOW CONFIDENCE TAF FORECAST. MANY GUIDANCE SOLUTIONS SHOWING IFR TO
MVFR STRATUS THIS MORNING. THESE SOLUTIONS SHOW IT DEVELOPING OVER
NEBRASKA AND IOWA AND ADVECTING INTO OUR AREA. WINDS ARE
SOUTHEASTERLY FROM 1500 FEET AND BELOW AND SOUTHWESTERLY ABOVE THAT.
THAT SOUTHWESTERLY WIND IS ADVECTING IN DRY AIR...THUS ONLY STRATUS
BELOW 1500 FEET WOULD BE ABLE TO ADVECT INTO THE AREA. CURRENTLY NOT
SEEING MUCH OF THAT OUT THERE. THUS CUT BACK ON THE LOW CIGS AND KEPT
MOST OF OUR AREA VFR. HOWEVER WILL HAVE TO MONITOR THINGS THROUGH THE
MORNING. NOT OUT OF THE QUESTION THAT LOW STRATUS STILL FORMS...OR
THAT WE GET SOME MVFR STRATOCU AFTER SUNRISE. NEXT PROBLEM IS
CONVECTION. THIS MORNINGS ACTIVITY SHOULD REMAIN EAST OF THE TAF
SITES AND EXIT THE CWA BY MID TO LATE MORNING. TONIGHT...EXPECT
ACTIVITY TO GET GOING IN THE VICINITY OF A LOW LEVEL WARM FRONT AFTER
03Z. WHERE THIS EXACTLY HAPPENS REMAINS UNCERTAIN. AT THIS POINT IT
APPEAR THAT AREAS NEAR THE MISSOURI RIVER HAVE THE BEST SHOT. ALSO
EXPECT A THUNDERSTORM COMPLEX TO FORM TO OUR NORTHWEST...AND DIVE
THROUGH THE AREA AFTER 7Z INTO THE MORNING HOURS. MAIN THREATS WILL
BE REDUCTIONS TO IFR VIS/CIG IN THE HEAVIER RAIN...BUT SOME HAIL AND
GUSTY WINDS ARE ALSO POSSIBLE. STRATUS MAY ALSO TRY TO FORM
TONIGHT...BUT THAT WILL BE DEPENDENT ON HOW WELL WE MIX OUT THE LOW
LEVEL MOISTURE TODAY. DID PUT MVFR CIGS IN THE TAFS STARTING THIS
EVENING...BUT THIS IS ALSO UNFORTUNATELY UNCERTAIN.

&&

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

$$

SHORT TERM...CHAPMAN/CHENARD
LONG TERM...CHAPMAN
AVIATION...CHENARD

000
FXUS63 KFSD 250931
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
431 AM CDT SAT MAY 25 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT SAT MAY 25 2013

THUNDERSTORM COMPLEX OVER NEBRASKA OVERNIGHT CONTINUES EARLY THIS
MORNING. SEEING SHOWERS AND STORMS BEGINNING TO EXPAND ACROSS
NORTHWEST IOWA AS WELL AS LOW LEVEL THETAE ADVECTION INCREASES. HIGH
RES MODEL SUITE LOOK TO HAVE A PRETTY GOOD HANDLE ON THIS ACTIVITY.
EXPECT IT TO CONTINUE THIS MORNING AND POSSIBLY EXPAND A BIT FURTHER
NORTH INTO PORTIONS OF SOUTHWEST MINNESOTA. LOWERED POPS ACROSS
SOUTHEAST SOUTH DAKOTA...AS ALL INDICATIONS ARE THAT THESE STORMS
WILL NOT DEVELOP NORTHWEST OF THEIR CURRENT LOCATION. MOST OF THE
STORMS SHOULD BE EAST OF THE CWA BY 16Z. MAIN IMPACTS WILL BE
BRIEFLY HEAVY RAIN AND POSSIBLY SMALL HAIL WITH THESE CELLS...AS
EFFECTIVE SHEAR AND CAPE ARE TOO LOW FOR ANY SEVERE THREAT. MUCH OF
THE AFTERNOON SHOULD THEN BE DRY ACROSS THE CWA WITH AN AREA OF
SUBSIDENCE LIKELY BEHIND THIS MORNINGS SHORTWAVE. WARM FRONTAL
BOUNDARY WILL POSITION ITSELF SOUTH OF THE MISSOURI RIVER THIS
AFTERNOON. HRRR AND RAP TRY TO BREAK THE CAP THEIR THIS
AFTERNOON...BUT BOTH THESE MODELS SEEM A BIT OVERDONE WITH DEWPOINTS
AND INSTABILITY. FEEL MORE LIKELY SCENARIO IS ACTIVITY WAITS FOR THE
LOW LEVEL JET TO KICK IN AFTER 0Z BEFORE IT GETS GOING.

OTHER ISSUE TODAY IS CLOUD COVER AND HIGH TEMPERATURES.
INTERESTINGLY THE HRRR AND RAP ARE COMPLETE OPPOSITE OF EACH
OTHER...GIVING AROUND A 20 DEGREE DIFFERENCE IN HIGHS...WITH THE RAP
HAVING MORE STRATUS AND COOLER TEMPERATURES. THE GEM AND ECMWF SIDE
CLOSER TO THE RAP...WITH THE NAM IN BETWEEN. SINCE THE AREAL
COVERAGE OF LOW STRATUS IS CURRENTLY LESS THAN EXPECTED...DID GO
AHEAD AND RAISE HIGHS SEVERAL DEGREES FOR TODAY IN OUR CENTRAL AND
WEST. ALSO THE HRRR HAS A GOOD HANDLE ON THE CURRENT SITUATION...SO
ONE WOULD THINK ITS SHORT RANGE FORECAST SHOULD BE SOMEWHAT
RELIABLE...AND IT HAS CONSISTENTLY BEEN WARM FOR TODAY. LOWERED
HIGHS A FEW IN THE EAST WHERE IT IS RAINING...AND WHERE STRATUS
SHOULD INDEED HOLD IN FOR MUCH OF THE DAY. AGAIN THIS IS A PRETTY
LOW CONFIDENCE TEMPERATURE FORECAST FOR ANYWHERE EAST OF THE JAMES
RIVER. BUT FEEL GOING FORECAST IS A DECENT STARTING POINT...WITH THE
DAY SHIFT LIKELY HAVING TO ADJUST UP OR DOWN DEPENDING ON CLOUD
COVER TRENDS.

QUIET SHORT TERM CONDITIONS FROM THE AFTERNOON HOURS SHOULD TURN
QUICKLY TO MORE STORMY CONDITIONS OVERNIGHT. GAVE A FAIR AMOUNT
OF CREDIT TO THE CONSISTENCY OF THE 00Z HIGH RESOLUTION NAMDNG5
AND WRF-ARW SOLUTIONS...WHICH FIT THE OVERALL CONCEPTUAL MODEL FOR
CONVECTIVE INITIATION TONIGHT. BOUNDARY FROM CURRENT NIGHT MCS
WILL BE FESTERING AND DRIFTING NORTHWARD...WITH LIKELY 1000 TO
1500 J/KG ELEVATED CAPE LIFTED FROM 1 TO 1.5 KM AGL. AS 35 TO 40
KNOT LOW LEVEL JET DEVELOPS TONIGHT THROUGH THE CENTRAL PLAINS...
SHOULD BECOME ENOUGH TO INITIATE ELEVATED THUNDERSTORMS NEAR/NORTH
OF THE BOUNDARY WHICH WILL BE DRIFTING NORTHWARD OF INTERSTATE 80
DURING THE EVENING HOURS. EFFECTIVE SHEAR IN AREAS NORTH OF THE
BOUNDARY WILL BE VERY CONCENTRATED IN THE 1-3KM LAYER WITH STRONGEST
WINDS IN LOW LEVELS AND WEAKENING MID LEVEL WINDS ROUGHLY 20-30
KNOTS...WITH LESSER DEEP LAYER SHEAR CONTRIBUTIONS FROM ABOVE. ALL
SUGGEST AT LEAST A MINIMAL THREAT FOR ISOLATED LARGER HAIL OR
DAMAGING WINDS THROUGH THE MISSOURI RIVER CORRIDOR AND LIFTING
SOMEWHAT NORTHWARD THROUGH 066-08Z. OTHER SIGNIFICANT CONVECTIVE
INITIATION IS LIKELY TO OCCUR BACK THROUGH THE WESTERN HIGH PLAINS
WHERE STRONGER SHEAR EXISTS WITH A BIT STRONGER MID LEVEL WINDS
TO AROUND 25 KNOTS...AS WELL AS THE DEEP UPSLOPE TRANSPORT OF MOISTURE
TO RESULT IN STRONGER INSTABILITY. EVENTUALLY...WHEN SUPERCELL MOTIONS
WHICH WILL TAKE ACTION MORE SOUTHWARD THAN EAST START TO EASE...AND
LOW LEVEL JET VEERS EASTWARD...WILL FIND A MORE LINEAR MCS LIKELY
TAKING SHAPE. MANY HI RES MODELS SUGGEST THIS MCS WILL ZIPPER DOWN
THE LOCATION OF THE WARM ADVECTION WING SPREADING NORTHWARD...MOVING
TOWARD EAST CENTRAL SD AND SOUTHWEST MN LATE NIGHT. SEVERE THREAT
WITH THIS FEATURE WOULD SEEM TO BE SOMEWHAT LOWER...BUT LIKELY TO
GET SOME GUSTY WINDS AND AREAS OF HEAVY RAINFALL.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 430 AM CDT SAT MAY 25 2013

MCS EXPECTED TO WEAKEN AND SHIFT EAST ON SUNDAY...AND WITH MID
LEVEL FORCING SHOWING TENDENCY TO FORCE SUBSIDENCE AROUND
MIDDAY...AGAIN EXPECT THAT MUCH OF THE DAYTIME PERIOD WILL
PROBABLY END UP PRECIPITATION FREE. HOWEVER...CLOUDS LIKELY TO
PERSIST WITH STRATUS DEVELOPING IN WAKE OF SYSTEM. MOST LIKELY TO
GET BREAKS THROUGH THE WESTERN AND SOUTHERN CWA DURING THE
AFTERNOON...AND HAVE PUSHED EXPECTED TEMPS TO NEAR 80 THERE...
WHILE MORE MID TO UPPER 60S LINGER IN THE FAR EAST. RESULT OF THIS
WILL BE GENERATION OF DECENT POTENTIAL INSTABILITY OF 1500-2000
J/KG ACROSS THE AREA...WITH WEAKEST OF THE CAPPING INVERSION NEAR
THE MISSOURI RIVER CORRIDOR. SHEAR BECOMES A BIT MORE DISTRIBUTED
THROUGH THE EFFECTIVE LAYER...AND FAIRLY CLOSE TO THOSE VALUES
FROM THIS EVENING FROM 30 TO 35 KNOTS. A FEW MORE SEVERE STORMS
WOULD BE POSSIBLE MAINLY THROUGH THE SOUTHWEST HALF OF THE AREA
DURING THE LATER AFTERNOON AND EVENING HOURS...AS INITIATION
LIKELY TO BE A RESULT OF WEAK IMPULSE SLIDING UP BACK SIDE OF
RIDGE IN THE LATER AFTERNOON AND EARLY EVENING.

THE FURTHER ONE GOES INTO THE FORECAST...THE LESS RELIABLE ANY
GUIDANCE BECOMES GIVEN THE ABUNDANCE OF CONVECTION...AND THE
INCREASINGLY GREAT UNCERTAINTY AS TO WHERE CRITICAL BOUNDARIES MAY
LIE. ONE THING FOR SURE...GIVEN THE CLOSED LOW ACROSS THE WESTERN
U.S. AND THE SOUTHWEST FLOW ALOFT...DIFFICULT TO PINPOINT ANY TIME
FROM MONDAY ON THAT ONE COULD SAY THERE WAS ABSOLUTELY NO CHANCE
FOR PRECIPITATION...BUT ON THE SAME FRONT IT CERTAINLY WILL NOT BE
AN ALL TIME WASHOUT WITH MANY BREAKS DEFINED ON THE MESOSCALE.
MEMORIAL DAY AND MONDAY NIGHT WILL PLACE THE AREA ON THE SOUTHERN
FLANK OF A COUPLE OF WAVES MOVING OVER THE RIDGE...SO LIKELY TO
HAVE ENHANCEMENT OF PRECIPITATION IN THE NOCTURNALLY FAVORED
PERIODS. WHILE A FEW SEVERE STORMS ARE AGAIN WELL WITHIN
REASON...HIGH PRECIPITABLE WATER AND FAIRLY SLOW MOVING WIND
PROFILES BRING THE CONCERN OF AREAS OF HEAVY RAINFALL...AT THIS
RANGE HARD TO DEFINE. AT THE MOMENT...THE PROSPECT FOR MORE
SIGNIFICANT CONVECTION AND SEVERE WEATHER WOULD APPEAR TO BE LATE
DAY WEDNESDAY INTO THURSDAY...AS DEEP WESTERN CLOSED LOW KICKS
STRONGER JET ENERGY INTO THE PLAINS. MOISTURE THROUGH LOWER LEVELS
/THUS INSTABILITY/ WILL CONTINUE TO BENEFIT FROM PERSISTENT
SOUTHERLY FLOW. TEMPERATURES WILL LIKELY GRAVITATE TO SOMEWHAT
ABOVE NORMAL READINGS THROUGH THE UPCOMING WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1103 PM CDT FRI MAY 24 2013

MODELS CONTINUE TO SHOW CEILINGS DETERIORATING INTO MVFR-IFR RANGE
LATER TONIGHT AT ALL TAF SITES. STARTING TO SEE HINTS OF MVFR CLOUDS
IN EASTERN NEBRASKA AS OF 04Z...SO WILL CONTINUE THIS DOWNWARD TREND
IN CEILINGS THROUGH THE FIRST 4-6 HOURS OF TAF PERIOD...WITH NEXT
CHANCE OF RAIN EXPANDING INTO SOUTHERN PARTS OF THE AREA ALONG WITH
THE LOWER CEILINGS. SOME MID LEVEL INSTABILITY PRESENT AS THE RAIN
MOVES INTO SOUTHWEST PARTS OF THE FORECAST AREA...BUT PRECIP MOVES
INTO MORE STABLE AIRMASS AS IT PROGRESSES EASTWARD...LEADING TO MORE
ISOLATED THUNDER THREAT ALONG AND EAST OF I-29 CORRIDOR. THUS HAVE
LEFT MENTION OF THUNDER OUT OF KFSD/KSUX TAFS AT THIS TIME...THOUGH
CANNOT COMPLETELY BE RULED OUT 08Z-15Z...ESPECIALLY AT KSUX. BULK OF
MVFR CEILINGS EXPECTED TO BECOME MORE SCATTERED THROUGH THE LATE
MORNING/EARLY AFTERNOON SATURDAY...THOUGH WITH MORE ABUNDANT LOW
LEVEL MOISTURE...POTENTIAL FOR MVFR CUMULUS AT TIMES THROUGH THE
AFTERNOON. GREATER CHANCE OF MVFR-IFR REDEVELOPMENT SATURDAY EVENING
WITH NEXT CHANCE OF CONVECTION SPREADING INTO THE AREA.


&&

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

$$

SHORT TERM...CHAPMAN/CHENARD
LONG TERM...CHAPMAN
AVIATION...

000
FXUS63 KFSD 250407
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1107 PM CDT FRI MAY 24 2013

.UPDATE...
ISSUED AT 930 PM CDT FRI MAY 24 2013

LATE AFTERNOON CONVECTION ROUND HAS MOVED EAST OF THE AREA WHILE
LEAVING VERY SPOTTY LIGHT SHOWERS FAR EAST. NEXT ROUND THE
DEVELOPED OVER WESTERN AND CENTRAL NE HAS BEEN TURNING MORE EAST
NORTHEAST WITH THE STRONGER CONVECTION AND EXPECT THIS TREND TO
CONTINUE. HOWEVER...FEEL THE SHORT TERM RAP CONTINUES TO BE MORE
IN TUNE WITH THE THREAT OF LIGHT TO MODERATE CONVECTION DEVELOPING
NORTH OF THIS AREA AND AFFECTING ESPECIALLY THE SOUTHERN EDGE OF
THE FORECAST AREA...MORE FAR SOUTHEAST VERY LATE TONIGHT. THE NAM
CONTINUES TO DOWNPLAY THIS THREAT. OVERALL LOW TEMPERATURES LOOK
OK WITH HOURLY READING EXPECTED TO GRADUALLY EVEN OUT...THAT IS
THE TEMPERATURES CONTRAST FROM SOUTH TO NORTH SHOULD DECREASE A
LITTLE.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 332 PM CDT FRI MAY 24 2013

SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE CWA WITH
THE MOST CONCENTRATED AREA NORTH OF INTERSTATE 90 AND EAST OF
INTERSTATE 29 THIS EVENING. WITH THE WAVE THAT IS AIDING IN THIS
DEVELOPMENT MOVING NORTHEAST SUSPECT THE TREND TO THE EAST AND
NORTH WITH THIS ACTIVITY WILL CONTINUE. SHEAR AND INSTABILITY NOT
ENOUGH FOR SEVERE THUNDERSTORMS BUT SOME VERY SMALL HAIL POSSIBLE
WITH THE STRONGER STORMS. BETWEEN ABOUT 3Z TO 6Z THE LOW LEVEL JET
INCREASES QUITE A BIT IN CENTRAL NEBRASKA AND BEGINS TO FOCUS THE
BEST CONVERGENCE/ADVECTION TOWARDS THE MISSOURI RIVER ALONG THE
SOUTH DAKOTA NEBRASKA BORDER. THE WEAKEST CIN AND HIGHEST CAPE
VALUES SUGGEST THAT A PARCEL LIFTED FROM ABOUT 850MB TO 800MB WOULD
HAVE ABOUT 1500 J/KG TO WORK WITH. WHILE THE EFFECTIVE SHEAR IS
QUITE WEAK SOME NICKEL TO DIME SIZED HAIL WOULD BE POSSIBLE NEAR THE
MISSOURI RIVER. WITH FAIRLY SLOW STORM MOTION ANY STORMS THAT COULD
DEVELOP WOULD HAVE THE POTENTIAL TO PRODUCE SOME HEAVIER RAINFALL.
WILL KEEP THE HIGHEST POPS ALONG THE MISSOURI RIVER INTO NORTHWEST
IOWA OVERNIGHT WITH A TREND DOWNWARD IN RAIN AND THUNDERSTORM
POTENTIAL ON SATURDAY. OTHER THAN CONVECTIVE BLOW OFF OR SOMETHING
THAT ADVECTS IN IT LOOKS LIKE CAPPING WILL KEEP THUNDERSTORMS AT BAY
MOST OF THE DAY IN MOST LOCATIONS. STILL EXPECTING QUITE A BIT OF
CLOUD COVER AND COOL TEMPERATURES...RANGING FROM THE MID 60S EAST OF
THE BUFFALO RIDGE TO 75 TO 80 IN SOUTH CENTRAL SOUTH DAKOTA.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 332 PM CDT FRI MAY 24 2013

MODELS SUGGEST THAT A PAIR OF WAVES MAY BEGIN NOSING INTO BLACK
HILLS AREA SATURDAY AFTERNOON AND AGAIN SUNDAY AFTERNOON...
TRIGGERING CONVECTION TO OUR WEST SATURDAY EVENING AND SOUTHWEST ON
SUNDAY EVENING. WITH A QUASI-STATIONARY BOUNDARY DRAPED ACROSS THE
REGION...VERY HIGH PRECIPITABLE WATER AMOUNTS THROUGHOUT THE REGION
AND A STRENGTHENING LOW LEVEL JET NEAR THE MISSOURI RIVER BOTH
NIGHTS...EXPECT SHOWER AND THUNDERSTORM POTENTIAL TO PEAK DURING THE
EVENING AND OVERNIGHT HOURS. MAIN CONCERN WITH THIS CONVECTION WOULD BE
LOCALLY HEAVY RAINFALL AMOUNTS AND STRONG WIND GUSTS. MARGINALLY
SEVERE HAIL WILL ALSO BE POSSIBLE...HOWEVER THIS THREAT WOULD BE
MAINLY DURING THE EVENING HOURS. PRECIPITATION CHANCES DO DIMINISH
SLIGHTLY DURING THE DAY ON SUNDAY...BUT WILL KEEP SCATTERED MENTION
GOING THROUGH THE DAY WITH SOME TIMING UNCERTAINTY.

VERY ACTIVE AND WET PATTERN IS EXPECTED TO PERSIST THROUGH THE
ENTIRE MID AND LONG RANGE WITH PRECIPITATION IN THE FORECAST EACH
PERIOD...INCLUDING MEMORIAL DAY. STILL SEEING QUITE A BIT OF
UNCERTAINTY WITH TIMING ALL OF THE SHORTWAVES TRACKING THROUGH THE
REGION ALONG THE GENERAL UPPER LEVEL SOUTHWEST FLOW. WEST COAST
TROUGHING STARTS NUDGING FURTHER EAST INTO THE HIGH PLAINS LATE WEEK
NEXT WEEK...HOWEVER THE SLOW MOVING NATURE OF THIS SYSTEM KEEPS
IT...AND PRECIPITATION IN THE FORECAST EVEN THROUGH NEXT WEEKEND.
TEMPERATURES WILL WARM A LITTLE TO SLIGHTLY ABOVE NORMAL READINGS
AROUND MID WEEK BUT WILL START TO COOL A BIT LATE WEEK WITH POTENTIAL
TROUGHING ARRIVING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1103 PM CDT FRI MAY 24 2013

MODELS CONTINUE TO SHOW CEILINGS DETERIORATING INTO MVFR-IFR RANGE
LATER TONIGHT AT ALL TAF SITES. STARTING TO SEE HINTS OF MVFR CLOUDS
IN EASTERN NEBRASKA AS OF 04Z...SO WILL CONTINUE THIS DOWNWARD TREND
IN CEILINGS THROUGH THE FIRST 4-6 HOURS OF TAF PERIOD...WITH NEXT
CHANCE OF RAIN EXPANDING INTO SOUTHERN PARTS OF THE AREA ALONG WITH
THE LOWER CEILINGS. SOME MID LEVEL INSTABILITY PRESENT AS THE RAIN
MOVES INTO SOUTHWEST PARTS OF THE FORECAST AREA...BUT PRECIP MOVES
INTO MORE STABLE AIRMASS AS IT PROGRESSES EASTWARD...LEADING TO MORE
ISOLATED THUNDER THREAT ALONG AND EAST OF I-29 CORRIDOR. THUS HAVE
LEFT MENTION OF THUNDER OUT OF KFSD/KSUX TAFS AT THIS TIME...THOUGH
CANNOT COMPLETELY BE RULED OUT 08Z-15Z...ESPECIALLY AT KSUX. BULK OF
MVFR CEILINGS EXPECTED TO BECOME MORE SCATTERED THROUGH THE LATE
MORNING/EARLY AFTERNOON SATURDAY...THOUGH WITH MORE ABUNDANT LOW
LEVEL MOISTURE...POTENTIAL FOR MVFR CUMULUS AT TIMES THROUGH THE
AFTERNOON. GREATER CHANCE OF MVFR-IFR REDEVELOPMENT SATURDAY EVENING
WITH NEXT CHANCE OF CONVECTION SPREADING INTO THE AREA.

&&

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

&&

$$

UPDATE...
SHORT TERM...08
LONG TERM...
AVIATION...

000
FXUS63 KFSD 250230
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
930 PM CDT FRI MAY 24 2013

.UPDATE...
ISSUED AT 930 PM CDT FRI MAY 24 2013

LATE AFTERNOON CONVECTION ROUND HAS MOVED EAST OF THE AREA WHILE
LEAVING VERY SPOTTY LIGHT SHOWERS FAR EAST. NEXT ROUND THE
DEVELOPED OVER WESTERN AND CENTRAL NE HAS BEEN TURNING MORE EAST
NORTHEAST WITH THE STRONGER CONVECTION AND EXPECT THIS TREND TO
CONTINUE. HOWEVER...FEEL THE SHORT TERM RAP CONTINUES TO BE MORE
IN TUNE WITH THE THREAT OF LIGHT TO MODERATE CONVECTION DEVELOPING
NORTH OF THIS AREA AND AFFECTING ESPECIALLY THE SOUTHERN EDGE OF
THE FORECAST AREA...MORE FAR SOUTHEAST VERY LATE TONIGHT. THE NAM
CONTINUES TO DOWNPLAY THIS THREAT. OVERALL LOW TEMPERATURES LOOK
OK WITH HOURLY READING EXPECTED TO GRADUALLY EVEN OUT...THAT IS
THE TEMPERATURES CONTRAST FROM SOUTH TO NORTH SHOULD DECREASE A
LITTLE.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 332 PM CDT FRI MAY 24 2013

SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE CWA WITH
THE MOST CONCENTRATED AREA NORTH OF INTERSTATE 90 AND EAST OF
INTERSTATE 29 THIS EVENING. WITH THE WAVE THAT IS AIDING IN THIS
DEVELOPMENT MOVING NORTHEAST SUSPECT THE TREND TO THE EAST AND
NORTH WITH THIS ACTIVITY WILL CONTINUE. SHEAR AND INSTABILITY NOT
ENOUGH FOR SEVERE THUNDERSTORMS BUT SOME VERY SMALL HAIL POSSIBLE
WITH THE STRONGER STORMS. BETWEEN ABOUT 3Z TO 6Z THE LOW LEVEL JET
INCREASES QUITE A BIT IN CENTRAL NEBRASKA AND BEGINS TO FOCUS THE
BEST CONVERGENCE/ADVECTION TOWARDS THE MISSOURI RIVER ALONG THE
SOUTH DAKOTA NEBRASKA BORDER. THE WEAKEST CIN AND HIGHEST CAPE
VALUES SUGGEST THAT A PARCEL LIFTED FROM ABOUT 850MB TO 800MB WOULD
HAVE ABOUT 1500 J/KG TO WORK WITH. WHILE THE EFFECTIVE SHEAR IS
QUITE WEAK SOME NICKEL TO DIME SIZED HAIL WOULD BE POSSIBLE NEAR THE
MISSOURI RIVER. WITH FAIRLY SLOW STORM MOTION ANY STORMS THAT COULD
DEVELOP WOULD HAVE THE POTENTIAL TO PRODUCE SOME HEAVIER RAINFALL.
WILL KEEP THE HIGHEST POPS ALONG THE MISSOURI RIVER INTO NORTHWEST
IOWA OVERNIGHT WITH A TREND DOWNWARD IN RAIN AND THUNDERSTORM
POTENTIAL ON SATURDAY. OTHER THAN CONVECTIVE BLOW OFF OR SOMETHING
THAT ADVECTS IN IT LOOKS LIKE CAPPING WILL KEEP THUNDERSTORMS AT BAY
MOST OF THE DAY IN MOST LOCATIONS. STILL EXPECTING QUITE A BIT OF
CLOUD COVER AND COOL TEMPERATURES...RANGING FROM THE MID 60S EAST OF
THE BUFFALO RIDGE TO 75 TO 80 IN SOUTH CENTRAL SOUTH DAKOTA.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 332 PM CDT FRI MAY 24 2013

MODELS SUGGEST THAT A PAIR OF WAVES MAY BEGIN NOSING INTO BLACK
HILLS AREA SATURDAY AFTERNOON AND AGAIN SUNDAY AFTERNOON...
TRIGGERING CONVECTION TO OUR WEST SATURDAY EVENING AND SOUTHWEST ON
SUNDAY EVENING. WITH A QUASI-STATIONARY BOUNDARY DRAPED ACROSS THE
REGION...VERY HIGH PRECIPITABLE WATER AMOUNTS THROUGHOUT THE REGION
AND A STRENGTHENING LOW LEVEL JET NEAR THE MISSOURI RIVER BOTH
NIGHTS...EXPECT SHOWER AND THUNDERSTORM POTENTIAL TO PEAK DURING THE
EVENING AND OVERNIGHT HOURS. MAIN CONCERN WITH THIS CONVECTION WOULD BE
LOCALLY HEAVY RAINFALL AMOUNTS AND STRONG WIND GUSTS. MARGINALLY
SEVERE HAIL WILL ALSO BE POSSIBLE...HOWEVER THIS THREAT WOULD BE
MAINLY DURING THE EVENING HOURS. PRECIPITATION CHANCES DO DIMINISH
SLIGHTLY DURING THE DAY ON SUNDAY...BUT WILL KEEP SCATTERED MENTION
GOING THROUGH THE DAY WITH SOME TIMING UNCERTAINTY.

VERY ACTIVE AND WET PATTERN IS EXPECTED TO PERSIST THROUGH THE
ENTIRE MID AND LONG RANGE WITH PRECIPITATION IN THE FORECAST EACH
PERIOD...INCLUDING MEMORIAL DAY. STILL SEEING QUITE A BIT OF
UNCERTAINTY WITH TIMING ALL OF THE SHORTWAVES TRACKING THROUGH THE
REGION ALONG THE GENERAL UPPER LEVEL SOUTHWEST FLOW. WEST COAST
TROUGHING STARTS NUDGING FURTHER EAST INTO THE HIGH PLAINS LATE WEEK
NEXT WEEK...HOWEVER THE SLOW MOVING NATURE OF THIS SYSTEM KEEPS
IT...AND PRECIPITATION IN THE FORECAST EVEN THROUGH NEXT WEEKEND.
TEMPERATURES WILL WARM A LITTLE TO SLIGHTLY ABOVE NORMAL READINGS
AROUND MID WEEK BUT WILL START TO COOL A BIT LATE WEEK WITH POTENTIAL
TROUGHING ARRIVING.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 650 PM CDT FRI MAY 24 2013

WILL SEE A BREAK FROM PRECIPITATION THE REMAINDER OF THE EVENING AS
FIRST WAVE SHIFTS EAST OF THE FORECAST AREA. MODELS CONTINUE TO SHOW
CEILINGS DETERIORATING INTO MVFR RANGE LATER TONIGHT AT ALL TAF SITES
WITH AREAS OF IFR CEILINGS AS WELL...SO WILL CONTINUE THIS DOWNWARD
TREND IN CEILINGS AFTER 06Z...WITH NEXT CHANCE OF RAIN EXPANDING
INTO SOUTHERN PARTS OF THE AREA ALONG WITH THE LOWER CEILINGS. SOME
MID LEVEL INSTABILITY PRESENT AS THE RAIN MOVES INTO SOUTHWEST PARTS
OF THE FORECAST AREA...BUT PRECIP MOVES INTO MORE STABLE AIRMASS AS
IT PROGRESSES EASTWARD...LEADING TO MORE ISOLATED THUNDER THREAT
ALONG AND EAST OF I-29 CORRIDOR. THUS HAVE LEFT MENTION OF THUNDER
OUT OF KFSD/KSUX TAFS AT THIS TIME...THOUGH CANNOT COMPLETELY BE
RULED OUT 08Z-15Z. BULK OF MVFR CEILINGS EXPECTED TO BECOME MORE
SCATTERED THROUGH THE LATE MORNING/MIDDAY HOURS SATURDAY...THOUGH
WITH MORE ABUNDANT LOW LEVEL MOISTURE...POTENTIAL FOR MVFR CUMULUS
REDEVELOPING ACROSS THE MISSOURI VALLEY INCLUDING KSUX THROUGH THE
AFTERNOON.


&&

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

$$

UPDATE...
SHORT TERM...08
LONG TERM...
AVIATION...JH

000
FXUS63 KFSD 242350
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
650 PM CDT FRI MAY 24 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 332 PM CDT FRI MAY 24 2013

SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE CWA WITH
THE MOST CONCENTRATED AREA NORTH OF INTERSTATE 90 AND EAST OF
INTERSTATE 29 THIS EVENING. WITH THE WAVE THAT IS AIDING IN THIS
DEVELOPMENT MOVING NORTHEAST SUSPECT THE TREND TO THE EAST AND
NORTH WITH THIS ACTIVITY WILL CONTINUE. SHEAR AND INSTABILITY NOT
ENOUGH FOR SEVERE THUNDERSTORMS BUT SOME VERY SMALL HAIL POSSIBLE
WITH THE STRONGER STORMS. BETWEEN ABOUT 3Z TO 6Z THE LOW LEVEL JET
INCREASES QUITE A BIT IN CENTRAL NEBRASKA AND BEGINS TO FOCUS THE
BEST CONVERGENCE/ADVECTION TOWARDS THE MISSOURI RIVER ALONG THE
SOUTH DAKOTA NEBRASKA BORDER. THE WEAKEST CIN AND HIGHEST CAPE
VALUES SUGGEST THAT A PARCEL LIFTED FROM ABOUT 850MB TO 800MB WOULD
HAVE ABOUT 1500 J/KG TO WORK WITH. WHILE THE EFFECTIVE SHEAR IS
QUITE WEAK SOME NICKEL TO DIME SIZED HAIL WOULD BE POSSIBLE NEAR THE
MISSOURI RIVER. WITH FAIRLY SLOW STORM MOTION ANY STORMS THAT COULD
DEVELOP WOULD HAVE THE POTENTIAL TO PRODUCE SOME HEAVIER RAINFALL.
WILL KEEP THE HIGHEST POPS ALONG THE MISSOURI RIVER INTO NORTHWEST
IOWA OVERNIGHT WITH A TREND DOWNWARD IN RAIN AND THUNDERSTORM
POTENTIAL ON SATURDAY. OTHER THAN CONVECTIVE BLOW OFF OR SOMETHING
THAT ADVECTS IN IT LOOKS LIKE CAPPING WILL KEEP THUNDERSTORMS AT BAY
MOST OF THE DAY IN MOST LOCATIONS. STILL EXPECTING QUITE A BIT OF
CLOUD COVER AND COOL TEMPERATURES...RANGING FROM THE MID 60S EAST OF
THE BUFFALO RIDGE TO 75 TO 80 IN SOUTH CENTRAL SOUTH DAKOTA.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 332 PM CDT FRI MAY 24 2013

MODELS SUGGEST THAT A PAIR OF WAVES MAY BEGIN NOSING INTO BLACK
HILLS AREA SATURDAY AFTERNOON AND AGAIN SUNDAY AFTERNOON...
TRIGGERING CONVECTION TO OUR WEST SATURDAY EVENING AND SOUTHWEST ON
SUNDAY EVENING. WITH A QUASI-STATIONARY BOUNDARY DRAPED ACROSS THE
REGION...VERY HIGH PRECIPITABLE WATER AMOUNTS THROUGHOUT THE REGION
AND A STRENGTHENING LOW LEVEL JET NEAR THE MISSOURI RIVER BOTH
NIGHTS...EXPECT SHOWER AND THUNDERSTORM POTENTIAL TO PEAK DURING THE
EVENING AND OVERNIGHT HOURS. MAIN CONCERN WITH THIS CONVECTION WOULD BE
LOCALLY HEAVY RAINFALL AMOUNTS AND STRONG WIND GUSTS. MARGINALLY
SEVERE HAIL WILL ALSO BE POSSIBLE...HOWEVER THIS THREAT WOULD BE
MAINLY DURING THE EVENING HOURS. PRECIPITATION CHANCES DO DIMINISH
SLIGHTLY DURING THE DAY ON SUNDAY...BUT WILL KEEP SCATTERED MENTION
GOING THROUGH THE DAY WITH SOME TIMING UNCERTAINTY.

VERY ACTIVE AND WET PATTERN IS EXPECTED TO PERSIST THROUGH THE
ENTIRE MID AND LONG RANGE WITH PRECIPITATION IN THE FORECAST EACH
PERIOD...INCLUDING MEMORIAL DAY. STILL SEEING QUITE A BIT OF
UNCERTAINTY WITH TIMING ALL OF THE SHORTWAVES TRACKING THROUGH THE
REGION ALONG THE GENERAL UPPER LEVEL SOUTHWEST FLOW. WEST COAST
TROUGHING STARTS NUDGING FURTHER EAST INTO THE HIGH PLAINS LATE WEEK
NEXT WEEK...HOWEVER THE SLOW MOVING NATURE OF THIS SYSTEM KEEPS
IT...AND PRECIPITATION IN THE FORECAST EVEN THROUGH NEXT WEEKEND.
TEMPERATURES WILL WARM A LITTLE TO SLIGHTLY ABOVE NORMAL READINGS
AROUND MID WEEK BUT WILL START TO COOL A BIT LATE WEEK WITH POTENTIAL
TROUGHING ARRIVING.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 650 PM CDT FRI MAY 24 2013

WILL SEE A BREAK FROM PRECIPITATION THE REMAINDER OF THE EVENING AS
FIRST WAVE SHIFTS EAST OF THE FORECAST AREA. MODELS CONTINUE TO SHOW
CEILINGS DETERIORATING INTO MVFR RANGE LATER TONIGHT AT ALL TAF SITES
WITH AREAS OF IFR CEILINGS AS WELL...SO WILL CONTINUE THIS DOWNWARD
TREND IN CEILINGS AFTER 06Z...WITH NEXT CHANCE OF RAIN EXPANDING
INTO SOUTHERN PARTS OF THE AREA ALONG WITH THE LOWER CEILINGS. SOME
MID LEVEL INSTABILITY PRESENT AS THE RAIN MOVES INTO SOUTHWEST PARTS
OF THE FORECAST AREA...BUT PRECIP MOVES INTO MORE STABLE AIRMASS AS
IT PROGRESSES EASTWARD...LEADING TO MORE ISOLATED THUNDER THREAT
ALONG AND EAST OF I-29 CORRIDOR. THUS HAVE LEFT MENTION OF THUNDER
OUT OF KFSD/KSUX TAFS AT THIS TIME...THOUGH CANNOT COMPLETELY BE
RULED OUT 08Z-15Z. BULK OF MVFR CEILINGS EXPECTED TO BECOME MORE
SCATTERED THROUGH THE LATE MORNING/MIDDAY HOURS SATURDAY...THOUGH
WITH MORE ABUNDANT LOW LEVEL MOISTURE...POTENTIAL FOR MVFR CUMULUS
REDEVELOPING ACROSS THE MISSOURI VALLEY INCLUDING KSUX THROUGH THE
AFTERNOON.

&&

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

$$

SHORT TERM...08
LONG TERM...
AVIATION...JH

000
FXUS63 KFSD 242043
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
343 PM CDT FRI MAY 24 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 332 PM CDT FRI MAY 24 2013

SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE CWA WITH
THE MOST CONCENTRATED AREA NORTH OF INTERSTATE 90 AND EAST OF
INTERSTATE 29 THIS EVENING. WITH THE WAVE THAT IS AIDING IN THIS
DEVELOPMENT MOVING NORTHEAST SUSPECT THE TREND TO THE EAST AND
NORTH WITH THIS ACTIVITY WILL CONTINUE. SHEAR AND INSTABILITY NOT
ENOUGH FOR SEVERE THUNDERSTORMS BUT SOME VERY SMALL HAIL POSSIBLE
WITH THE STRONGER STORMS. BETWEEN ABOUT 3Z TO 6Z THE LOW LEVEL JET
INCREASES QUITE A BIT IN CENTRAL NEBRASKA AND BEGINS TO FOCUS THE
BEST CONVERGENCE/ADVECTION TOWARDS THE MISSOURI RIVER ALONG THE
SOUTH DAKOTA NEBRASKA BORDER. THE WEAKEST CIN AND HIGHEST CAPE
VALUES SUGGEST THAT A PARCEL LIFTED FROM ABOUT 850MB TO 800MB WOULD
HAVE ABOUT 1500 J/KG TO WORK WITH. WHILE THE EFFECTIVE SHEAR IS
QUITE WEAK SOME NICKEL TO DIME SIZED HAIL WOULD BE POSSIBLE NEAR THE
MISSOURI RIVER. WITH FAIRLY SLOW STORM MOTION ANY STORMS THAT COULD
DEVELOP WOULD HAVE THE POTENTIAL TO PRODUCE SOME HEAVIER RAINFALL.
WILL KEEP THE HIGHEST POPS ALONG THE MISSOURI RIVER INTO NORTHWEST
IOWA OVERNIGHT WITH A TREND DOWNWARD IN RAIN AND THUNDERSTORM
POTENTIAL ON SATURDAY. OTHER THAN CONVECTIVE BLOW OFF OR SOMETHING
THAT ADVECTS IN IT LOOKS LIKE CAPPING WILL KEEP THUNDERSTORMS AT BAY
MOST OF THE DAY IN MOST LOCATIONS. STILL EXPECTING QUITE A BIT OF
CLOUD COVER AND COOL TEMPERATURES...RANGING FROM THE MID 60S EAST OF
THE BUFFALO RIDGE TO 75 TO 80 IN SOUTH CENTRAL SOUTH DAKOTA.


.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 332 PM CDT FRI MAY 24 2013

MODELS SUGGEST THAT A PAIR OF WAVES MAY BEGIN NOSING INTO BLACK
HILLS AREA SATURDAY AFTERNOON AND AGAIN SUNDAY AFTERNOON...
TRIGGERING CONVECTION TO OUR WEST SATURDAY EVENING AND SOUTHWEST ON
SUNDAY EVENING. WITH A QUASI-STATIONARY BOUNDARY DRAPED ACROSS THE
REGION...VERY HIGH PRECIPITABLE WATER AMOUNTS THROUGHOUT THE REGION
AND A STRENGTHENING LOW LEVEL JET NEAR THE MISSOURI RIVER BOTH
NIGHTS...EXPECT SHOWER AND THUNDERSTORM POTENTIAL TO PEAK DURING THE
EVENING AND OVERNIGHT HOURS. MAIN CONCERN WITH THIS CONVECTION WOULD BE
LOCALLY HEAVY RAINFALL AMOUNTS AND STRONG WIND GUSTS. MARGINALLY
SEVERE HAIL WILL ALSO BE POSSIBLE...HOWEVER THIS THREAT WOULD BE
MAINLY DURING THE EVENING HOURS. PRECIPITATION CHANCES DO DIMINISH
SLIGHTLY DURING THE DAY ON SUNDAY...BUT WILL KEEP SCATTERED MENTION
GOING THROUGH THE DAY WITH SOME TIMING UNCERTAINTY.

VERY ACTIVE AND WET PATTERN IS EXPECTED TO PERSIST THROUGH THE
ENTIRE MID AND LONG RANGE WITH PRECIPITATION IN THE FORECAST EACH
PERIOD...INCLUDING MEMORIAL DAY. STILL SEEING QUITE A BIT OF
UNCERTAINTY WITH TIMING ALL OF THE SHORTWAVES TRACKING THROUGH THE
REGION ALONG THE GENERAL UPPER LEVEL SOUTHWEST FLOW. WEST COAST
TROUGHING STARTS NUDGING FURTHER EAST INTO THE HIGH PLAINS LATE WEEK
NEXT WEEK...HOWEVER THE SLOW MOVING NATURE OF THIS SYSTEM KEEPS
IT...AND PRECIPITATION IN THE FORECAST EVEN THROUGH NEXT WEEKEND.
TEMPERATURES WILL WARM A LITTLE TO SLIGHTLY ABOVE NORMAL READINGS
AROUND MID WEEK BUT WILL START TO COOL A BIT LATE WEEK WITH POTENTIAL
TROUGHING ARRIVING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1240 PM CDT FRI MAY 24 2013

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OCCURRING OVER SOUTH
DAKOTA WILL GRADUALLY WORK EASTWARD THROUGH THE DAY. COVERAGE
SHOULD NOT BE VERY HIGH SO THE MENTION OF THUNDER HAS BEEN REMOVED
FROM THE TAF FORECASTS. WHILE THERE WILL BE A FEW THUNDERSTORMS
HERE AND THERE COVERAGE WILL BE MINIMAL AND ANY LOCATION THAT DOES
RECEIVE SOME ANY THUNDER IT SHOULD ONLY LAST FOR ABOUT 10 TO 15
MINUTES. SOUTH TO SOUTHEAST WINDS WILL GUSTS TO AROUND 30 MPH AT
TIMES THROUGH SUNSET. OTHERWISE LATE TONIGHT...MAINLY AFTER ABOUT
7Z...SOME MVFR CEILINGS WILL BE POSSIBLE.


&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR SDZ050-052-057-058-
     063-064.

MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...08
LONG TERM...
AVIATION...08

000
FXUS63 KFSD 241743
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1243 PM CDT FRI MAY 24 2013

.UPDATE...
ISSUED AT 1027 AM CDT FRI MAY 24 2013

NO MAJOR CHANGES TO THE FORECAST THIS AFTERNOON. MAY AT SOME POINT
IN TIME NEED TO DECREASE POPS BUT WITH SHOWERS DEVELOPING WILL
WAIT A LITTLE AND SEE BUT STARTING TO LOOK MUCH MORE SCATTERED IN
NATURE SO SOMETHING IN THE 30 TO 50 PERCENT RANGE MAY BE NEEDED.
OTHERWISE STUCK OUT A SHORT WIND ADVISORY FOR THIS AFTERNOON IN
CENTRAL SOUTH DAKOTA. SHOULD BE A PRETTY LOW END ADVISORY WITH
SUSTAINED WINDS OF 25 TO 35 MPH. THE STRONGEST WINDS WILL LIKELY BE
IN GREGORY COUNTY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CDT FRI MAY 24 2013

SHARP RIDGING ALOFT CURRENTLY ACROSS THE CWA WILL GRADUALLY LOSE
HOLD AS MID LEVEL FEATURE SHIFTS EASTWARD AND IMPINGES A BIT MORE
SOUTHWESTERLY FLOW THROUGH THE DAY. KEEWATIN HIGH CONTINUES TO
FILTER DRIER AIR AT LOW LEVELS INTO THE AREA ON EASTERLY FLOW...
BUT MOISTENING ON STRONG LOW LEVEL JET THROUGH THE WESTERN PLAINS
LEADING TO EXPANSION OF LOWER TO MID CLOUDS ACROSS WESTERN SOUTH
DAKOTA AND WESTERN AND CENTRAL NEBRASKA GRADUALLY BUILDING EASTWARD.
MORE MID LEVEL CLOUDS SHOWING UP OF LATE IN SOUTHWEST NEBRASKA...AND
AREA CORRELATES QUITE WELL WITH DEVELOPMENT OF STRONGER ISENTROPIC
LIFT.  LIFT SPREADS RAPIDLY EAST AND NORTHEAST AND WILL BE ACROSS
MUCH OF SOUTHEAST SOUTH DAKOTA BETWEEN 12Z AND 15Z. HOWEVER...LIKELY
THE LEADING MID LEVEL SHOWERS WILL DIMINISH LIFTING NORTHEAST WHILE
RUNNING INTO DRIER AIR WITH PERHAPS A COUPLE OF SPRINKLES SOMEWHAT
AHEAD OF THE MAIN AREA OF PRECIPITATION...EXPECTED TO START TO
DEVELOP BY LATER MORNING FROM LOWER BRULE AREAS INTO THE LOWER JAMES
VALLEY.  MUCH OF TIMING FOR PRECIPITATION DEFINED BY 305K NET
ISENTROPIC LIFT...CONSIDERING WHERE DRIER AIR AT LOW LEVELS WILL
IMPEDE PROGRESS SOMEWHAT. CONTINUED TO INTRODUCE AN INCREASINGLY
BETTER COVERAGE FOR SHOWERS AS LIFT FORCING SPREADS EAST TOWARDS AND
EAST OF I29 DURING THE AFTERNOON HOURS. GENERALLY 200-500 J/KG
ELEVATED INSTABILITY FROM IN AND AROUND 750 HPA LEVEL INITIATION...
SO WHILE THUNDER WILL BE FAR FROM PREVALENT...DOES WARRANT A MORE
ISOLATED MENTION.

SHOULD ALSO NOTE THAT IT WILL BE QUITE A WINDY DAY ALONG AND WEST OF
I29...ESPECIALLY FROM THE JAMES VALLEY WEST. AT THIS TIME...LIKELY
WILL BE MARGINAL FOR ISSUANCE OF A WIND ADVISORY...BUT WOULD NOT BE
SHOCKED TO TOUCH 30 MPH SUSTAINED OR EVEN GUST TO AROUND 40 MPH AT
TIMES.

THE SURFACE WINDS WILL GRADUALLY DECREASE THROUGH THE EVENING
HOURS AND WILL DROP MORE AFTER MIDNIGHT AS WINDS ALOFT GRADUALLY
WEAKEN WITH TIME. THE BAND OF WARM AIR ADVECTION/THETA-E ADVECTION
PRECIPITATION IS GRADUALLY EXPECTED TO SHIFT OFF TO THE EAST. NOT
MUCH IN THE WAY OF INSTABILITY...AND TOYED WITH THE IDEA OF
REDUCING THUNDER MENTION IN THE FORECAST.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 412 AM CDT FRI MAY 24 2013

TOUGH FORECAST THROUGH THE EXTENDED WITH ACTIVE PATTERN AND LITTLE
CERTAINTY IN HOW EVERYTHING WILL PLAY OUT. ON SATURDAY...MODEL
SOUNDINGS APPEAR TO BE VERY SATURATED ESPECIALLY IN THE LOW
LEVELS. MODELS CONTINUE TO WARM THE LOW LEVELS DESPITE THIS...BUT
AM CONCERNED IT WOULD TAKE TILL AT LEAST MID DAY IF NOT LONGER TO
ERODE STRATUS IN THE LOWEST 1500 FEET. AS SUCH...LOWERED FORECAST
HIGHS SOME ESPECIALLY IN THE NORTH AND EAST PORTIONS OF THE
FORECAST AREA WHERE STRATUS WILL BE THE MOST STUBBORN. THIS ALSO PLAYS
INTO THE AMOUNT OF INSTABILITY. SURFACE BASED CAPE IN SOUTHWEST
CORNER OF THE FORECAST AREA CLIMBS TO NEAR 1500 J/KG THROUGHOUT
THE DAY...BUT STILL APPEARS TO BE EFFECTIVELY CAPPED AT LEAST FROM
THE SURFACE. UNLIKE LAST NIGHT/S MODEL RUNS...MODELS HAVE BACKED
OFF SOME ON THE LOW LEVEL JET SATURDAY NIGHT...BRINGING FORCING
INTO A QUESTION. AGREE WITH PREVIOUS FORECASTER THAT TALL THIN
CAPE PROFILES AND PRECIPITABLE WATER VALUES NEAR 1.30 CREATE GREAT
ANTECEDENT CONDITIONS FOR FLASH FLOODING. WITH WEAK MID LEVEL WINDS...
PRECIPITABLE WATER VALUES WELL ABOVE THE 95 PERCENTILE AND THE
POTENTIAL FOR A NEARLY STATIONARY BOUNDARY...FIELD APPEARS TO BE
SET...HOWEVER...ONE THING MISSING APPEARS TO BE A TRIGGER ACROSS
THE AREA. CAN/T RULE OUT CONVECTION MOVING INTO THE REGION...BUT
AT THIS POINT AM BEGINNING TO QUESTION POPS AND HAVE TRENDED DOWN
SLIGHTLY.

SIMILAR SET UP SUNDAY WITH LOW LEVEL SATURATION...HOWEVER...APPEARS
TO BE MORE SHALLOW AND WITH SLIGHTLY STRONGER WINDS MAY BE ABLE TO
MIX OUT STRATUS WITH DAY TIME HEATING. WITH WARM FRONT HANGING
ACROSS THE AREA...HAVE A FOCUSING MECHANISM BUT ATMOSPHERE STILL
APPEARS TO BE CAPPED AT LEAST FROM THE SURFACE. MODELS REALLY TRY
TO ERODE THE CAP BY LATE IN THE DAY AS WAVE APPROACHES FROM THE
SOUTHWEST...QUESTION BECOMES WHETHER ELEVATED INVERSION WILL ERODE
THAT QUICKLY. STILL APPEARS TO BE A GOOD SET UP FOR FLASH FLOODING
WITH PWAT VALUES NEAR 1.3 INCHES...ESPECIALLY FOR ANY STORMS THAT
WOULD BE ABLE TO TRAIN IN THE SAME AREA. SHEAR PROFILES DON/T
SUPPORT A WIDESPREAD OUTBREAK OF SEVERE WEATHER....BUT MAY BE ABLE
TO GET AN ISOLATED STORM OR TWO TO PRODUCE MARGINALLY SEVERE HAIL
BASED ON INSTABILITY...ESPECIALLY IF STORMS ARE ABLE TO DEVELOP IN
THE NEAR SURFACE LAYER.

MUCH OF NEXT WEEK CONTINUES TO REMAIN ACTIVE WITH DIRTY SOUTHWEST
FLOW ALOFT AND SHORT WAVE TRAIN MOVING ACROSS THE AREA OVER THE
NEXT SEVERAL DAYS AHEAD OF A UPPER LEVEL LOW THAT IS EXPECTED TO
IMPACT THE REGION NEXT WEEKEND. MODELS ARE MUCH WEAKER WITH UPPER
RIDGING IN THE MID WEEK...AND THEREFORE...KEPT MEDIUM RANGE POPS
THROUGH THE EXTENDED WITH THE CHANCE OF THUNDERSTORMS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1240 PM CDT FRI MAY 24 2013

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OCCURRING OVER SOUTH
DAKOTA WILL GRADUALLY WORK EASTWARD THROUGH THE DAY. COVERAGE
SHOULD NOT BE VERY HIGH SO THE MENTION OF THUNDER HAS BEEN REMOVED
FROM THE TAF FORECASTS. WHILE THERE WILL BE A FEW THUNDERSTORMS
HERE AND THERE COVERAGE WILL BE MINIMAL AND ANY LOCATION THAT DOES
RECEIVE SOME ANY THUNDER IT SHOULD ONLY LAST FOR ABOUT 10 TO 15
MINUTES. SOUTH TO SOUTHEAST WINDS WILL GUSTS TO AROUND 30 MPH AT
TIMES THROUGH SUNSET. OTHERWISE LATE TONIGHT...MAINLY AFTER ABOUT
7Z...SOME MVFR CEILINGS WILL BE POSSIBLE.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR SDZ050-052-057-058-
     063-064.

MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

UPDATE...08
SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...08

000
FXUS63 KFSD 241530
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1030 AM CDT FRI MAY 24 2013

.UPDATE...
ISSUED AT 1027 AM CDT FRI MAY 24 2013

NO MAJOR CHANGES TO THE FORECAST THIS AFTERNOON. MAY AT SOME POINT
IN TIME NEED TO DECREASE POPS BUT WITH SHOWERS DEVELOPING WILL
WAIT A LITTLE AND SEE BUT STARTING TO LOOK MUCH MORE SCATTERED IN
NATURE SO SOMETHING IN THE 30 TO 50 PERCENT RANGE MAY BE NEEDED.
OTHERWISE STUCK OUT A SHORT WIND ADVISORY FOR THIS AFTERNOON IN
CENTRAL SOUTH DAKOTA. SHOULD BE A PRETTY LOW END ADVISORY WITH
SUSTAINED WINDS OF 25 TO 35 MPH. THE STRONGEST WINDS WILL LIKELY BE
IN GREGORY COUNTY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CDT FRI MAY 24 2013

SHARP RIDGING ALOFT CURRENTLY ACROSS THE CWA WILL GRADUALLY LOSE
HOLD AS MID LEVEL FEATURE SHIFTS EASTWARD AND IMPINGES A BIT MORE
SOUTHWESTERLY FLOW THROUGH THE DAY. KEEWATIN HIGH CONTINUES TO
FILTER DRIER AIR AT LOW LEVELS INTO THE AREA ON EASTERLY FLOW...
BUT MOISTENING ON STRONG LOW LEVEL JET THROUGH THE WESTERN PLAINS
LEADING TO EXPANSION OF LOWER TO MID CLOUDS ACROSS WESTERN SOUTH
DAKOTA AND WESTERN AND CENTRAL NEBRASKA GRADUALLY BUILDING EASTWARD.
MORE MID LEVEL CLOUDS SHOWING UP OF LATE IN SOUTHWEST NEBRASKA...AND
AREA CORRELATES QUITE WELL WITH DEVELOPMENT OF STRONGER ISENTROPIC
LIFT.  LIFT SPREADS RAPIDLY EAST AND NORTHEAST AND WILL BE ACROSS
MUCH OF SOUTHEAST SOUTH DAKOTA BETWEEN 12Z AND 15Z. HOWEVER...LIKELY
THE LEADING MID LEVEL SHOWERS WILL DIMINISH LIFTING NORTHEAST WHILE
RUNNING INTO DRIER AIR WITH PERHAPS A COUPLE OF SPRINKLES SOMEWHAT
AHEAD OF THE MAIN AREA OF PRECIPITATION...EXPECTED TO START TO
DEVELOP BY LATER MORNING FROM LOWER BRULE AREAS INTO THE LOWER JAMES
VALLEY.  MUCH OF TIMING FOR PRECIPITATION DEFINED BY 305K NET
ISENTROPIC LIFT...CONSIDERING WHERE DRIER AIR AT LOW LEVELS WILL
IMPEDE PROGRESS SOMEWHAT. CONTINUED TO INTRODUCE AN INCREASINGLY
BETTER COVERAGE FOR SHOWERS AS LIFT FORCING SPREADS EAST TOWARDS AND
EAST OF I29 DURING THE AFTERNOON HOURS. GENERALLY 200-500 J/KG
ELEVATED INSTABILITY FROM IN AND AROUND 750 HPA LEVEL INITIATION...
SO WHILE THUNDER WILL BE FAR FROM PREVALENT...DOES WARRANT A MORE
ISOLATED MENTION.

SHOULD ALSO NOTE THAT IT WILL BE QUITE A WINDY DAY ALONG AND WEST OF
I29...ESPECIALLY FROM THE JAMES VALLEY WEST. AT THIS TIME...LIKELY
WILL BE MARGINAL FOR ISSUANCE OF A WIND ADVISORY...BUT WOULD NOT BE
SHOCKED TO TOUCH 30 MPH SUSTAINED OR EVEN GUST TO AROUND 40 MPH AT
TIMES.

THE SURFACE WINDS WILL GRADUALLY DECREASE THROUGH THE EVENING
HOURS AND WILL DROP MORE AFTER MIDNIGHT AS WINDS ALOFT GRADUALLY
WEAKEN WITH TIME. THE BAND OF WARM AIR ADVECTION/THETA-E ADVECTION
PRECIPITATION IS GRADUALLY EXPECTED TO SHIFT OFF TO THE EAST. NOT
MUCH IN THE WAY OF INSTABILITY...AND TOYED WITH THE IDEA OF
REDUCING THUNDER MENTION IN THE FORECAST.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 412 AM CDT FRI MAY 24 2013

TOUGH FORECAST THROUGH THE EXTENDED WITH ACTIVE PATTERN AND LITTLE
CERTAINTY IN HOW EVERYTHING WILL PLAY OUT. ON SATURDAY...MODEL
SOUNDINGS APPEAR TO BE VERY SATURATED ESPECIALLY IN THE LOW
LEVELS. MODELS CONTINUE TO WARM THE LOW LEVELS DESPITE THIS...BUT
AM CONCERNED IT WOULD TAKE TILL AT LEAST MID DAY IF NOT LONGER TO
ERODE STRATUS IN THE LOWEST 1500 FEET. AS SUCH...LOWERED FORECAST
HIGHS SOME ESPECIALLY IN THE NORTH AND EAST PORTIONS OF THE
FORECAST AREA WHERE STRATUS WILL BE THE MOST STUBBORN. THIS ALSO PLAYS
INTO THE AMOUNT OF INSTABILITY. SURFACE BASED CAPE IN SOUTHWEST
CORNER OF THE FORECAST AREA CLIMBS TO NEAR 1500 J/KG THROUGHOUT
THE DAY...BUT STILL APPEARS TO BE EFFECTIVELY CAPPED AT LEAST FROM
THE SURFACE. UNLIKE LAST NIGHT/S MODEL RUNS...MODELS HAVE BACKED
OFF SOME ON THE LOW LEVEL JET SATURDAY NIGHT...BRINGING FORCING
INTO A QUESTION. AGREE WITH PREVIOUS FORECASTER THAT TALL THIN
CAPE PROFILES AND PRECIPITABLE WATER VALUES NEAR 1.30 CREATE GREAT
ANTECEDENT CONDITIONS FOR FLASH FLOODING. WITH WEAK MID LEVEL WINDS...
PRECIPITABLE WATER VALUES WELL ABOVE THE 95 PERCENTILE AND THE
POTENTIAL FOR A NEARLY STATIONARY BOUNDARY...FIELD APPEARS TO BE
SET...HOWEVER...ONE THING MISSING APPEARS TO BE A TRIGGER ACROSS
THE AREA. CAN/T RULE OUT CONVECTION MOVING INTO THE REGION...BUT
AT THIS POINT AM BEGINNING TO QUESTION POPS AND HAVE TRENDED DOWN
SLIGHTLY.

SIMILAR SET UP SUNDAY WITH LOW LEVEL SATURATION...HOWEVER...APPEARS
TO BE MORE SHALLOW AND WITH SLIGHTLY STRONGER WINDS MAY BE ABLE TO
MIX OUT STRATUS WITH DAY TIME HEATING. WITH WARM FRONT HANGING
ACROSS THE AREA...HAVE A FOCUSING MECHANISM BUT ATMOSPHERE STILL
APPEARS TO BE CAPPED AT LEAST FROM THE SURFACE. MODELS REALLY TRY
TO ERODE THE CAP BY LATE IN THE DAY AS WAVE APPROACHES FROM THE
SOUTHWEST...QUESTION BECOMES WHETHER ELEVATED INVERSION WILL ERODE
THAT QUICKLY. STILL APPEARS TO BE A GOOD SET UP FOR FLASH FLOODING
WITH PWAT VALUES NEAR 1.3 INCHES...ESPECIALLY FOR ANY STORMS THAT
WOULD BE ABLE TO TRAIN IN THE SAME AREA. SHEAR PROFILES DON/T
SUPPORT A WIDESPREAD OUTBREAK OF SEVERE WEATHER....BUT MAY BE ABLE
TO GET AN ISOLATED STORM OR TWO TO PRODUCE MARGINALLY SEVERE HAIL
BASED ON INSTABILITY...ESPECIALLY IF STORMS ARE ABLE TO DEVELOP IN
THE NEAR SURFACE LAYER.

MUCH OF NEXT WEEK CONTINUES TO REMAIN ACTIVE WITH DIRTY SOUTHWEST
FLOW ALOFT AND SHORT WAVE TRAIN MOVING ACROSS THE AREA OVER THE
NEXT SEVERAL DAYS AHEAD OF A UPPER LEVEL LOW THAT IS EXPECTED TO
IMPACT THE REGION NEXT WEEKEND. MODELS ARE MUCH WEAKER WITH UPPER
RIDGING IN THE MID WEEK...AND THEREFORE...KEPT MEDIUM RANGE POPS
THROUGH THE EXTENDED WITH THE CHANCE OF THUNDERSTORMS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 645 AM CDT FRI MAY 24 2013

KHON ON EDGE OF STRONGER GRADIENT ALOFT THIS MORNING...AND WILL
KEEP A COUPLE HOURS OF NON CONVECTIVE LOW LEVEL WIND SHEAR TO
START THE MORNING BEFORE THE WIND PROFILE STARTS TO MIX OUT.
OTHERWISE...MASS OF LOWER TO MID LEVEL CLOUDS DEVELOPING IN
WARM AIR ADVECTION ZONE THROUGH MUCH OF NEBRASKA AND SOUTH DAKOTA.
AS A WEAK WAVE SLIDES UP THROUGH THE WESTERN PLAINS...THIS WILL
HELP TO IGNITE SHOWERS AND A FEW THUNDERSTORMS IN FOCUSED WARM AIR
ADVECTION ZONE PUSHING ACROSS THE AREA TODAY. ALL INDICATIONS ARE
THAT LIFT FORCING WILL BECOME MORE FOCUSED AS AREA SHIFTS TO NEAR
AND EAST OF INTERSTATE 29 BY AFTERNOON. WITH INSTABILITY PROFILES
FAIRLY NARROW...PREFER TO KEEP OVERALL THUNDER MENTION WITH BAND
MINIMAL. FAVORABLE SET UP FOR DEVELOPING STRATUS FIELD BEHIND
PRECIPITATION OVERNIGHT TONIGHT...AND LIKELY TO GET INTO LOWER
MVFR TO UPPER IFR CEILINGS ALONG WITH SOME MVFR VISIBILITIES.


&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR SDZ050-052-057-058-
     063-064.

MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

UPDATE...08
SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...CHAPMAN

000
FXUS63 KFSD 241146
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
646 AM CDT FRI MAY 24 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CDT FRI MAY 24 2013

SHARP RIDGING ALOFT CURRENTLY ACROSS THE CWA WILL GRADUALLY LOSE
HOLD AS MID LEVEL FEATURE SHIFTS EASTWARD AND IMPINGES A BIT MORE
SOUTHWESTERLY FLOW THROUGH THE DAY. KEEWATIN HIGH CONTINUES TO
FILTER DRIER AIR AT LOW LEVELS INTO THE AREA ON EASTERLY FLOW...
BUT MOISTENING ON STRONG LOW LEVEL JET THROUGH THE WESTERN PLAINS
LEADING TO EXPANSION OF LOWER TO MID CLOUDS ACROSS WESTERN SOUTH
DAKOTA AND WESTERN AND CENTRAL NEBRASKA GRADUALLY BUILDING EASTWARD.
MORE MID LEVEL CLOUDS SHOWING UP OF LATE IN SOUTHWEST NEBRASKA...AND
AREA CORRELATES QUITE WELL WITH DEVELOPMENT OF STRONGER ISENTROPIC
LIFT.  LIFT SPREADS RAPIDLY EAST AND NORTHEAST AND WILL BE ACROSS
MUCH OF SOUTHEAST SOUTH DAKOTA BETWEEN 12Z AND 15Z. HOWEVER...LIKELY
THE LEADING MID LEVEL SHOWERS WILL DIMINISH LIFTING NORTHEAST WHILE
RUNNING INTO DRIER AIR WITH PERHAPS A COUPLE OF SPRINKLES SOMEWHAT
AHEAD OF THE MAIN AREA OF PRECIPITATION...EXPECTED TO START TO
DEVELOP BY LATER MORNING FROM LOWER BRULE AREAS INTO THE LOWER JAMES
VALLEY.  MUCH OF TIMING FOR PRECIPITATION DEFINED BY 305K NET
ISENTROPIC LIFT...CONSIDERING WHERE DRIER AIR AT LOW LEVELS WILL
IMPEDE PROGRESS SOMEWHAT. CONTINUED TO INTRODUCE AN INCREASINGLY
BETTER COVERAGE FOR SHOWERS AS LIFT FORCING SPREADS EAST TOWARDS AND
EAST OF I29 DURING THE AFTERNOON HOURS. GENERALLY 200-500 J/KG
ELEVATED INSTABILITY FROM IN AND AROUND 750 HPA LEVEL INITIATION...
SO WHILE THUNDER WILL BE FAR FROM PREVALENT...DOES WARRANT A MORE
ISOLATED MENTION.

SHOULD ALSO NOTE THAT IT WILL BE QUITE A WINDY DAY ALONG AND WEST OF
I29...ESPECIALLY FROM THE JAMES VALLEY WEST. AT THIS TIME...LIKELY
WILL BE MARGINAL FOR ISSUANCE OF A WIND ADVISORY...BUT WOULD NOT BE
SHOCKED TO TOUCH 30 MPH SUSTAINED OR EVEN GUST TO AROUND 40 MPH AT
TIMES.

THE SURFACE WINDS WILL GRADUALLY DECREASE THROUGH THE EVENING
HOURS AND WILL DROP MORE AFTER MIDNIGHT AS WINDS ALOFT GRADUALLY
WEAKEN WITH TIME. THE BAND OF WARM AIR ADVECTION/THETA-E ADVECTION
PRECIPITATION IS GRADUALLY EXPECTED TO SHIFT OFF TO THE EAST. NOT
MUCH IN THE WAY OF INSTABILITY...AND TOYED WITH THE IDEA OF
REDUCING THUNDER MENTION IN THE FORECAST.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 412 AM CDT FRI MAY 24 2013

TOUGH FORECAST THROUGH THE EXTENDED WITH ACTIVE PATTERN AND LITTLE
CERTAINTY IN HOW EVERYTHING WILL PLAY OUT. ON SATURDAY...MODEL
SOUNDINGS APPEAR TO BE VERY SATURATED ESPECIALLY IN THE LOW
LEVELS. MODELS CONTINUE TO WARM THE LOW LEVELS DESPITE THIS...BUT
AM CONCERNED IT WOULD TAKE TILL AT LEAST MID DAY IF NOT LONGER TO
ERODE STRATUS IN THE LOWEST 1500 FEET. AS SUCH...LOWERED FORECAST
HIGHS SOME ESPECIALLY IN THE NORTH AND EAST PORTIONS OF THE
FORECAST AREA WHERE STRATUS WILL BE THE MOST STUBBORN. THIS ALSO PLAYS
INTO THE AMOUNT OF INSTABILITY. SURFACE BASED CAPE IN SOUTHWEST
CORNER OF THE FORECAST AREA CLIMBS TO NEAR 1500 J/KG THROUGHOUT
THE DAY...BUT STILL APPEARS TO BE EFFECTIVELY CAPPED AT LEAST FROM
THE SURFACE. UNLIKE LAST NIGHT/S MODEL RUNS...MODELS HAVE BACKED
OFF SOME ON THE LOW LEVEL JET SATURDAY NIGHT...BRINGING FORCING
INTO A QUESTION. AGREE WITH PREVIOUS FORECASTER THAT TALL THIN
CAPE PROFILES AND PRECIPITABLE WATER VALUES NEAR 1.30 CREATE GREAT
ANTECEDENT CONDITIONS FOR FLASH FLOODING. WITH WEAK MID LEVEL WINDS...
PRECIPITABLE WATER VALUES WELL ABOVE THE 95 PERCENTILE AND THE
POTENTIAL FOR A NEARLY STATIONARY BOUNDARY...FIELD APPEARS TO BE
SET...HOWEVER...ONE THING MISSING APPEARS TO BE A TRIGGER ACROSS
THE AREA. CAN/T RULE OUT CONVECTION MOVING INTO THE REGION...BUT
AT THIS POINT AM BEGINNING TO QUESTION POPS AND HAVE TRENDED DOWN
SLIGHTLY.

SIMILAR SET UP SUNDAY WITH LOW LEVEL SATURATION...HOWEVER...APPEARS
TO BE MORE SHALLOW AND WITH SLIGHTLY STRONGER WINDS MAY BE ABLE TO
MIX OUT STRATUS WITH DAY TIME HEATING. WITH WARM FRONT HANGING
ACROSS THE AREA...HAVE A FOCUSING MECHANISM BUT ATMOSPHERE STILL
APPEARS TO BE CAPPED AT LEAST FROM THE SURFACE. MODELS REALLY TRY
TO ERODE THE CAP BY LATE IN THE DAY AS WAVE APPROACHES FROM THE
SOUTHWEST...QUESTION BECOMES WHETHER ELEVATED INVERSION WILL ERODE
THAT QUICKLY. STILL APPEARS TO BE A GOOD SET UP FOR FLASH FLOODING
WITH PWAT VALUES NEAR 1.3 INCHES...ESPECIALLY FOR ANY STORMS THAT
WOULD BE ABLE TO TRAIN IN THE SAME AREA. SHEAR PROFILES DON/T
SUPPORT A WIDESPREAD OUTBREAK OF SEVERE WEATHER....BUT MAY BE ABLE
TO GET AN ISOLATED STORM OR TWO TO PRODUCE MARGINALLY SEVERE HAIL
BASED ON INSTABILITY...ESPECIALLY IF STORMS ARE ABLE TO DEVELOP IN
THE NEAR SURFACE LAYER.

MUCH OF NEXT WEEK CONTINUES TO REMAIN ACTIVE WITH DIRTY SOUTHWEST
FLOW ALOFT AND SHORT WAVE TRAIN MOVING ACROSS THE AREA OVER THE
NEXT SEVERAL DAYS AHEAD OF A UPPER LEVEL LOW THAT IS EXPECTED TO
IMPACT THE REGION NEXT WEEKEND. MODELS ARE MUCH WEAKER WITH UPPER
RIDGING IN THE MID WEEK...AND THEREFORE...KEPT MEDIUM RANGE POPS
THROUGH THE EXTENDED WITH THE CHANCE OF THUNDERSTORMS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 645 AM CDT FRI MAY 24 2013

KHON ON EDGE OF STRONGER GRADIENT ALOFT THIS MORNING...AND WILL
KEEP A COUPLE HOURS OF NON CONVECTIVE LOW LEVEL WIND SHEAR TO
START THE MORNING BEFORE THE WIND PROFILE STARTS TO MIX OUT.
OTHERWISE...MASS OF LOWER TO MID LEVEL CLOUDS DEVELOPING IN
WARM AIR ADVECTION ZONE THROUGH MUCH OF NEBRASKA AND SOUTH DAKOTA.
AS A WEAK WAVE SLIDES UP THROUGH THE WESTERN PLAINS...THIS WILL
HELP TO IGNITE SHOWERS AND A FEW THUNDERSTORMS IN FOCUSED WARM AIR
ADVECTION ZONE PUSHING ACROSS THE AREA TODAY. ALL INDICATIONS ARE
THAT LIFT FORCING WILL BECOME MORE FOCUSED AS AREA SHIFTS TO NEAR
AND EAST OF INTERSTATE 29 BY AFTERNOON. WITH INSTABILITY PROFILES
FAIRLY NARROW...PREFER TO KEEP OVERALL THUNDER MENTION WITH BAND
MINIMAL. FAVORABLE SET UP FOR DEVELOPING STRATUS FIELD BEHIND
PRECIPITATION OVERNIGHT TONIGHT...AND LIKELY TO GET INTO LOWER
MVFR TO UPPER IFR CEILINGS ALONG WITH SOME MVFR VISIBILITIES.

&&

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

$$

SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...CHAPMAN

000
FXUS63 KFSD 240912
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
412 AM CDT FRI MAY 24 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT FRI MAY 24 2013

SHARP RIDGING ALOFT CURRENTLY ACROSS THE CWA WILL GRADUALLY LOSE
HOLD AS MID LEVEL FEATURE SHIFTS EASTWARD AND IMPINGES A BIT MORE
SOUTHWESTERLY FLOW THROUGH THE DAY. KEEWATIN HIGH CONTINUES TO
FILTER DRIER AIR AT LOW LEVELS INTO THE AREA ON EASTERLY FLOW...
BUT MOISTENING ON STRONG LOW LEVEL JET THROUGH THE WESTERN PLAINS
LEADING TO EXPANSION OF LOWER TO MID CLOUDS ACROSS WESTERN SOUTH
DAKOTA AND WESTERN AND CENTRAL NEBRASKA GRADUALLY BUILDING EASTWARD.
MORE MID LEVEL CLOUDS SHOWING UP OF LATE IN SOUTHWEST NEBRASKA...AND
AREA CORRELATES QUITE WELL WITH DEVELOPMENT OF STRONGER ISENTROPIC
LIFT.  LIFT SPREADS RAPIDLY EAST AND NORTHEAST AND WILL BE ACROSS
MUCH OF SOUTHEAST SOUTH DAKOTA BETWEEN 12Z AND 15Z. HOWEVER...LIKELY
THE LEADING MID LEVEL SHOWERS WILL DIMINISH LIFTING NORTHEAST WHILE
RUNNING INTO DRIER AIR WITH PERHAPS A COUPLE OF SPRINKLES SOMEWHAT
AHEAD OF THE MAIN AREA OF PRECIPITATION...EXPECTED TO START TO
DEVELOP BY LATER MORNING FROM LOWER BRULE AREAS INTO THE LOWER JAMES
VALLEY.  MUCH OF TIMING FOR PRECIPITATION DEFINED BY 305K NET
ISENTROPIC LIFT...CONSIDERING WHERE DRIER AIR AT LOW LEVELS WILL
IMPEDE PROGRESS SOMEWHAT. CONTINUED TO INTRODUCE AN INCREASINGLY
BETTER COVERAGE FOR SHOWERS AS LIFT FORCING SPREADS EAST TOWARDS AND
EAST OF I29 DURING THE AFTERNOON HOURS. GENERALLY 200-500 J/KG
ELEVATED INSTABILITY FROM IN AND AROUND 750 HPA LEVEL INITIATION...
SO WHILE THUNDER WILL BE FAR FROM PREVALENT...DOES WARRANT A MORE
ISOLATED MENTION.

SHOULD ALSO NOTE THAT IT WILL BE QUITE A WINDY DAY ALONG AND WEST OF
I29...ESPECIALLY FROM THE JAMES VALLEY WEST. AT THIS TIME...LIKELY
WILL BE MARGINAL FOR ISSUANCE OF A WIND ADVISORY...BUT WOULD NOT BE
SHOCKED TO TOUCH 30 MPH SUSTAINED OR EVEN GUST TO AROUND 40 MPH AT
TIMES.

THE SURFACE WINDS WILL GRADUALLY DECREASE THROUGH THE EVENING
HOURS AND WILL DROP MORE AFTER MIDNIGHT AS WINDS ALOFT GRADUALLY
WEAKEN WITH TIME. THE BAND OF WARM AIR ADVECTION/THETA-E ADVECTION
PRECIPITATION IS GRADUALLY EXPECTED TO SHIFT OFF TO THE EAST. NOT
MUCH IN THE WAY OF INSTABILITY...AND TOYED WITH THE IDEA OF
REDUCING THUNDER MENTION IN THE FORECAST.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 330 AM CDT FRI MAY 24 2013

TOUGH FORECAST THROUGH THE EXTENDED WITH ACTIVE PATTERN AND LITTLE
CERTAINTY IN HOW EVERYTHING WILL PLAY OUT. ON SATURDAY...MODEL
SOUNDINGS APPEAR TO BE VERY SATURATED ESPECIALLY IN THE LOW
LEVELS. MODELS CONTINUE TO WARM THE LOW LEVELS DESPITE THIS...BUT
AM CONCERNED IT WOULD TAKE TILL AT LEAST MID DAY IF NOT LONGER TO
ERODE STRATUS IN THE LOWEST 1500 FEET. AS SUCH...LOWERED FORECAST
HIGHS SOME ESPECIALLY IN THE NORTH AND EAST PORTIONS OF THE
FORECAST AREA WHERE STRATUS WILL BE THE MOST STUBBORN. THIS ALSO PLAYS
INTO THE AMOUNT OF INSTABILITY. SURFACE BASED CAPE IN SOUTHWEST
CORNER OF THE FORECAST AREA CLIMBS TO NEAR 1500 J/KG THROUGHOUT
THE DAY...BUT STILL APPEARS TO BE EFFECTIVELY CAPPED AT LEAST FROM
THE SURFACE. UNLIKE LAST NIGHT/S MODEL RUNS...MODELS HAVE BACKED
OFF SOME ON THE LOW LEVEL JET SATURDAY NIGHT...BRINGING FORCING
INTO A QUESTION. AGREE WITH PREVIOUS FORECASTER THAT TALL THIN
CAPE PROFILES AND PRECIPITABLE WATER VALUES NEAR 1.30 CREATE GREAT
ANTECEDENT CONDITIONS FOR FLASH FLOODING. WITH WEAK MID LEVEL WINDS... PRECIPITATBLE
WATER VALUES WELL ABOVE THE 95 PERCENTILE AND THE POTENTIAL FOR A
NEARLY STATIONARY BOUNDARY...FIELD APPEARS TO BE
SET...HOWEVER...ONE THING MISSING APPEARS TO BE A TRIGGER ACROSS
THE AREA. CAN/T RULE OUT CONVECTION MOVING INTO THE REGION...BUT
AT THIS POINT AM BEGINNING TO QUESTION POPS AND HAVE TRENDED DOWN
SLIGHTLY.

SIMILAR SET UP SUNDAY WITH LOW LEVEL
SATURATION...HOWEVER...APPEARS TO BE MORE SHALLOW AND WITH
SLIGHTLY STRONGER WINDS MAY BE ABLE TO MIX OUT STRATUS WITH DAY
TIME HEATING. WITH WARM FRONT HANGING ACROSS THE AREA...HAVE A
FOCUSING MECHANISM BUT ATMOSPHERE STILL APPEARS TO BE CAPPED AT
LEAST FROM THE SURFACE. MODELS REALLY TRY TO ERODE THE CAP BY LATE
IN THE DAY AS WAVE APPROACHES FROM THE SOUTHWEST...QUESTION
BECOMES WHETHER ELEVATED INVERSION WILL ERODE THAT QUICKLY. STILL
APPEARS TO BE A GOOD SET UP FOR FLASH FLOODING WITH PWAT VALUES
NEAR 1.3 INCHES...ESPECIALLY FOR ANY STORMS THAT WOULD BE ABLE TO
TRAIN IN THE SAME AREA. SHEAR PROFILES DON/T SUPPORT A WIDESPREAD
OUTBREAK OF SEVERE WEATHER....BUT MAY BE ABLE TO GET AN ISOLATED
STORM OR TWO TO PRODUCE MARGINALLY SEVERE HAIL BASED ON
INSTABILITY...ESPECIALLY IF STORMS ARE ABLE TO DEVELOP IN THE NEAR
SURFACE LAYER.

MUCH OF NEXT WEEK CONTINUES TO REMAIN ACTIVE WITH DIRTY SOUTHWEST
FLOW ALOFT AND SHORT WAVE TRAIN MOVING ACROSS THE AREA OVER THE
NEXT SEVERAL DAYS AHEAD OF A UPPER LEVEL LOW THAT IS EXPECTED TO
IMPACT THE REGION NEXT WEEKEND. MODELS ARE MUCH WEAKER WITH UPPER
RIDGING IN THE MID WEEK...AND THEREFORE...KEPT MEDIUM RANGE POPS
THROUGH THE EXTENDED WITH THE CHANCE OF THUNDERSTORMS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1055 PM CDT THU MAY 23 2013

VFR THROUGH 24/12Z. 24/12Z-18Z AREAS OF CEILINGS 2-3K FEET AND
VISIBILITIES 3-5SM IN SHRA/TSRA WILL DEVELOP FROM THE WEST IN THE
AREA WEST OF INTERSTATE 29. THESE WILL CONTINUE IN THIS AREA
24/18Z-25/00Z. AFTER 25/00Z SHOWERS ARE NOT EXPECTED BUT CEILINGS
2-3K FEET MAY BECOMING WIDESPREAD. EAST OF INTERSTATE 29 AREAS OF
CEILINGS 2-3K FEET AND VISIBILITIES 3-5SM IN SHRA/TSRA WILL
DEVELOP FROM THE WEST AFTER 24/15Z. SHOWERS SHOULD END BY 25/03Z
BUT CEILINGS 2-3K FEET MAY BECOME WIDESPREAD NEAR THE END OF THE
PERIOD. SOUTH TO SOUTHEAST SURFACE GUSTS OF 25 TO 30 KNOTS WILL
DEVELOP WEST OF INTERSTATE 29 AFTER 24/12Z. GUSTS NEAR 25 KNOTS
WILL DEVELOP NEAR AND EAST OF INTERSTATE 29 AFTER 24/15Z. WINDS
WILL DECREASE AFTER 25/00Z.


&&

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

$$

SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...

000
FXUS63 KFSD 240356
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1056 PM CDT THU MAY 23 2013

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 305 PM CDT THU MAY 23 2013

HIGH PRESSURE ACROSS THE REGION WILL BEGIN TO PUSH OFF TO THE EAST
OVERNIGHT...AND THE MAIN EFFECT FROM THIS WILL BE TO BRING WINDS
AROUND TO A SOUTHEASTERLY DIRECTION IN THE RETURNING SOUTHERLY LOW
LEVEL FLOW ON THE BACKSIDE OF THE HIGH. WILL SEE THE DEVELOPMENT OF
A LOW LEVEL JET OVER WESTERN SOUTH DAKOTA DURING THE NIGHT TIME
HOURS...AND THIS WILL BEGIN TO NUDGE INTO OUR FAR WEST BY FRIDAY
MORNING AS A MID LEVEL SHORTWAVE BEGINS TO TRACK OUT OF THE ROCKIES.
WITH INCREASING MIDLEVEL THETA E ADVECTION VIA THE AFOREMENTIONED
JET AND WEAK ELEVATED INSTABILITY...MAY SEE SHOWERS AND
THUNDERSTORMS DEVELOP IN OUR FAR WEST EARLY FRIDAY MORNING...THEN
PUSH TO THE EAST DURING THE DAY ON FRIDAY AS THE SHORTWAVE AND A
SURFACE WARM LIFT UP OVER THE AREA. WOULD NOT EXPECT ANY SEVERE
STORMS WITH ONLY RELATIVELY WEAK INSTABILITY IN THE MID LEVELS AND
EFFECTIVE SHEAR IN THIS AREA ONLY AROUND 15 TO 20 KTS. FRIDAY WILL
BE A BREEZY DAY WITH WINDS OF AROUND 30 KTS AT THE TOP OF THE MIXED
LAYER AND A TIGHTENING GRADIENT IN OUR WEST AS THE SURFACE LOW
PRESSURE TRACKS OUT OF THE WESTERN HIGH PLAINS. IN TERMS OF
TEMPERATURES...THERMAL PROFILES WILL BEGIN TO WARM FROM THE WEST
TONIGHT...SO WILL SEE LOWS IN THE UPPER 40S THROUGH SOUTH CENTRAL
SOUTH DAKOTA/JAMES RIVER VALLEY...TO COOLER LOWER 40S IN OUR EAST.
IN SPITE OF THE WARMING THERMAL PROFILES...FRIDAYS TEMPERATURES WILL
BE SIMILAR TO TODAY WITH THE CLOUDS AND SHOWERS...TOPPING OUT IN THE
UPPER 60S TO AROUND 70.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 305 PM CDT THU MAY 23 2013

FRIDAY NIGHT IS A BIT OF A MESS TO DECIPHER THROUGH THE MODELS. AN
ELEVATED BAND OF RAIN AND THUNDERSTORMS WILL LIKELY EXIT THE EASTERN
CWA DURING THE EVENING ASSOCIATED WITH SOMETHING CLOSE TO THE
700-750MB LAYER. FROM ABOUT 3Z THROUGH 6Z THE LOW LEVEL JET WILL
CRANK UP AT ABOUT 850MB AND MAY ALLOW FOR MORE THUNDERSTORMS TO
DEVELOP AROUND THE MISSOURI RIVER AND TRACK EASTWARD AND LIKELY
TRACK INTO NORTHWEST IOWA. THE INITIAL ELEVATED BAND WILL LIKELY NOT
HAVE QUITE ENOUGH INSTABILITY OR SHEAR TO PRODUCE ANY SEVERE WEATHER
BUT THE SECOND AREA OF DEVELOPMENT MAY SEE CAP VALUES AROUND 1500
J/KG SO NOT OUT OF THE QUESTION TO PRODUCE SOME HAIL...ESPECIALLY
WITH ABOUT 30 TO 40 KNOTS OF SHEAR. THE FREEZING LEVEL IS AT ABOUT
11000 FEET SO PRETTY AVERAGE FOR THIS TIME OF YEAR. AN INTERESTING
NOTE...THE NAM BUFKIT SOUNDINGS ARE NOT MATCHING UP WITH THE NAM
PLAN VIEW OUTPUT IN AWIPS...RESULTING IN PRETTY BIG DIFFERENCES IN
SHEAR VALUES.

THE SET UP SATURDAY INTO SATURDAY NIGHT MAY POSE A THREAT FOR SEVERE
WEATHER AND POSSIBLY SOME HEAVY RAINFALL. WHILE UPPER LEVEL FLOW ON
THE LATEST RUNS OF THE MODELS HAS INCREASED A BIT...WHICH IS WHAT
BRINGS MORE OF A THREAT FOR SEVERE WEATHER WITH 0 TO 6KM BULK SHEAR
ABOUT 40 TO 45 KNOTS AND A FAIRLY STRONG CAPE GRADIENT ALONG THE
MISSOURI RIVER VALLEY WITH 2500 J/KG CAPES TO THE SOUTH OF THE
BOUNDARY. WHAT ALSO MAKES THIS AN INTERESTING SET UP IS THAT THE
TIMING OF THE WAVE ALLOWS FOR AN INCREASING LOW LEVEL JET THROUGH
THE EVENING SO IF STORMS CAN DEVELOP LATE AFTERNOON ALONG AND
NORTH OF THE BOUNDARY THERE SHOULD BE A STEADY OR INCREASING FEED OF
DEEPER MOISTURE AND BETTER INSTABILITY. RIGHT NOW SURFACE BASED
THUNDERSTORMS APPEAR UNLIKELY WITH A FAIRLY SIGNIFICANT CAP SO
BELIEVE ANY THUNDERSTORMS THAT CAN DEVELOP NORTH OF THE MISSOURI
RIVER WILL BE ELEVATED SO HAIL AND HEAVY RAIN WILL BE THE MAIN
THREATS.

BY SUNDAY THE THREAT FOR THUNDERSTORMS WILL CONTINUE AS BOUNDARY
LOOKS TO LINGER AROUND. WHILE INSTABILITY MAY STILL BE FAIRLY HIGH
AROUND 2000 J/KG IN THE SOUTHERN CWA SHEAR LOOKS TO DROP OFF
CONSIDERABLY. KIND OF A WAIT AND SEE FOR THIS DAY AS WITH CONVECTION
MANY TIMES THE BOUNDARY LOCATIONS WILL BE DEPENDENT UPON THE
CONVECTION OR LACK THEREOF THE PREVIOUS NIGHT. OTHERWISE THE
EXPECTATION IS THAT CLOUD COVER WILL KEEP TEMPERATURES IN CHECK A
BIT AS WILL THE THREAT FOR SHOWERS AND THUNDERSTORMS THROUGH THE
DAY. LOWS MID 50S TO LOWER 60S WITH HIGHS FROM 65 TO 70 IN SOUTHWEST
MINNESOTA TO NEAR 80 ALONG THE MISSOURI RIVER.

MONDAY THROUGH THURSDAY A VERY UNSETTLED PERIOD WITH THE WEST COAST
TROUGH MOVING INTO THE ROCKIES AND THEN POTENTIALLY ONTO THE PLAINS
LATE IN THE PERIOD. THIS ALLOWS THE GULF TO REMAIN FAIRLY OPEN AND
ANY WAVES THAT EJECT ONTO THE PLAINS WILL HAVE A GOOD CHANCE TO
PRODUCE THUNDERSTORMS. THIS MAKES IT PRETTY DIFFICULT TO PICK ANY
PERIODS OF TRULY DRY WEATHER. SO UNFORTUNATELY WILL HAVE THE CHANCE
FOR THUNDERSTORMS IN PRETTY MUCH EVERY PERIOD. AS THE TROUGH MOVES
ONTO THE PLAINS SHEAR WILL ALSO INCREASE SO THE POTENTIAL FOR SEVERE
WEATHER WILL LIKELY BE A LITTLE HIGHER WITH ANY STORMS THAT CAN
DEVELOP.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1055 PM CDT THU MAY 23 2013

VFR THROUGH 24/12Z. 24/12Z-18Z AREAS OF CEILINGS 2-3K FEET AND
VISIBILITIES 3-5SM IN SHRA/TSRA WILL DEVELOP FROM THE WEST IN THE
AREA WEST OF INTERSTATE 29. THESE WILL CONTINUE IN THIS AREA
24/18Z-25/00Z. AFTER 25/00Z SHOWERS ARE NOT EXPECTED BUT CEILINGS
2-3K FEET MAY BECOMING WIDESPREAD. EAST OF INTERSTATE 29 AREAS OF
CEILINGS 2-3K FEET AND VISIBILITIES 3-5SM IN SHRA/TSRA WILL
DEVELOP FROM THE WEST AFTER 24/15Z. SHOWERS SHOULD END BY 25/03Z
BUT CEILINGS 2-3K FEET MAY BECOME WIDESPREAD NEAR THE END OF THE
PERIOD. SOUTH TO SOUTHEAST SURFACE GUSTS OF 25 TO 30 KNOTS WILL
DEVELOP WEST OF INTERSTATE 29 AFTER 24/12Z. GUSTS NEAR 25 KNOTS
WILL DEVELOP NEAR AND EAST OF INTERSTATE 29 AFTER 24/15Z. WINDS
WILL DECREASE AFTER 25/00Z.

&&

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

$$

SHORT TERM...JM
LONG TERM...08
AVIATION...

000
FXUS63 KFSD 232300
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
600 PM CDT THU MAY 23 2013

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 305 PM CDT THU MAY 23 2013

HIGH PRESSURE ACROSS THE REGION WILL BEGIN TO PUSH OFF TO THE EAST
OVERNIGHT...AND THE MAIN EFFECT FROM THIS WILL BE TO BRING WINDS
AROUND TO A SOUTHEASTERLY DIRECTION IN THE RETURNING SOUTHERLY LOW
LEVEL FLOW ON THE BACKSIDE OF THE HIGH. WILL SEE THE DEVELOPMENT OF
A LOW LEVEL JET OVER WESTERN SOUTH DAKOTA DURING THE NIGHT TIME
HOURS...AND THIS WILL BEGIN TO NUDGE INTO OUR FAR WEST BY FRIDAY
MORNING AS A MID LEVEL SHORTWAVE BEGINS TO TRACK OUT OF THE ROCKIES.
WITH INCREASING MIDLEVEL THETA E ADVECTION VIA THE AFOREMENTIONED
JET AND WEAK ELEVATED INSTABILITY...MAY SEE SHOWERS AND
THUNDERSTORMS DEVELOP IN OUR FAR WEST EARLY FRIDAY MORNING...THEN
PUSH TO THE EAST DURING THE DAY ON FRIDAY AS THE SHORTWAVE AND A
SURFACE WARM LIFT UP OVER THE AREA. WOULD NOT EXPECT ANY SEVERE
STORMS WITH ONLY RELATIVELY WEAK INSTABILITY IN THE MID LEVELS AND
EFFECTIVE SHEAR IN THIS AREA ONLY AROUND 15 TO 20 KTS. FRIDAY WILL
BE A BREEZY DAY WITH WINDS OF AROUND 30 KTS AT THE TOP OF THE MIXED
LAYER AND A TIGHTENING GRADIENT IN OUR WEST AS THE SURFACE LOW
PRESSURE TRACKS OUT OF THE WESTERN HIGH PLAINS. IN TERMS OF
TEMPERATURES...THERMAL PROFILES WILL BEGIN TO WARM FROM THE WEST
TONIGHT...SO WILL SEE LOWS IN THE UPPER 40S THROUGH SOUTH CENTRAL
SOUTH DAKOTA/JAMES RIVER VALLEY...TO COOLER LOWER 40S IN OUR EAST.
IN SPITE OF THE WARMING THERMAL PROFILES...FRIDAYS TEMPERATURES WILL
BE SIMILAR TO TODAY WITH THE CLOUDS AND SHOWERS...TOPPING OUT IN THE
UPPER 60S TO AROUND 70.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 305 PM CDT THU MAY 23 2013

FRIDAY NIGHT IS A BIT OF A MESS TO DECIPHER THROUGH THE MODELS. AN
ELEVATED BAND OF RAIN AND THUNDERSTORMS WILL LIKELY EXIT THE EASTERN
CWA DURING THE EVENING ASSOCIATED WITH SOMETHING CLOSE TO THE
700-750MB LAYER. FROM ABOUT 3Z THROUGH 6Z THE LOW LEVEL JET WILL
CRANK UP AT ABOUT 850MB AND MAY ALLOW FOR MORE THUNDERSTORMS TO
DEVELOP AROUND THE MISSOURI RIVER AND TRACK EASTWARD AND LIKELY
TRACK INTO NORTHWEST IOWA. THE INITIAL ELEVATED BAND WILL LIKELY NOT
HAVE QUITE ENOUGH INSTABILITY OR SHEAR TO PRODUCE ANY SEVERE WEATHER
BUT THE SECOND AREA OF DEVELOPMENT MAY SEE CAP VALUES AROUND 1500
J/KG SO NOT OUT OF THE QUESTION TO PRODUCE SOME HAIL...ESPECIALLY
WITH ABOUT 30 TO 40 KNOTS OF SHEAR. THE FREEZING LEVEL IS AT ABOUT
11000 FEET SO PRETTY AVERAGE FOR THIS TIME OF YEAR. AN INTERESTING
NOTE...THE NAM BUFKIT SOUNDINGS ARE NOT MATCHING UP WITH THE NAM
PLAN VIEW OUTPUT IN AWIPS...RESULTING IN PRETTY BIG DIFFERENCES IN
SHEAR VALUES.

THE SET UP SATURDAY INTO SATURDAY NIGHT MAY POSE A THREAT FOR SEVERE
WEATHER AND POSSIBLY SOME HEAVY RAINFALL. WHILE UPPER LEVEL FLOW ON
THE LATEST RUNS OF THE MODELS HAS INCREASED A BIT...WHICH IS WHAT
BRINGS MORE OF A THREAT FOR SEVERE WEATHER WITH 0 TO 6KM BULK SHEAR
ABOUT 40 TO 45 KNOTS AND A FAIRLY STRONG CAPE GRADIENT ALONG THE
MISSOURI RIVER VALLEY WITH 2500 J/KG CAPES TO THE SOUTH OF THE
BOUNDARY. WHAT ALSO MAKES THIS AN INTERESTING SET UP IS THAT THE
TIMING OF THE WAVE ALLOWS FOR AN INCREASING LOW LEVEL JET THROUGH
THE EVENING SO IF STORMS CAN DEVELOP LATE AFTERNOON ALONG AND
NORTH OF THE BOUNDARY THERE SHOULD BE A STEADY OR INCREASING FEED OF
DEEPER MOISTURE AND BETTER INSTABILITY. RIGHT NOW SURFACE BASED
THUNDERSTORMS APPEAR UNLIKELY WITH A FAIRLY SIGNIFICANT CAP SO
BELIEVE ANY THUNDERSTORMS THAT CAN DEVELOP NORTH OF THE MISSOURI
RIVER WILL BE ELEVATED SO HAIL AND HEAVY RAIN WILL BE THE MAIN
THREATS.

BY SUNDAY THE THREAT FOR THUNDERSTORMS WILL CONTINUE AS BOUNDARY
LOOKS TO LINGER AROUND. WHILE INSTABILITY MAY STILL BE FAIRLY HIGH
AROUND 2000 J/KG IN THE SOUTHERN CWA SHEAR LOOKS TO DROP OFF
CONSIDERABLY. KIND OF A WAIT AND SEE FOR THIS DAY AS WITH CONVECTION
MANY TIMES THE BOUNDARY LOCATIONS WILL BE DEPENDENT UPON THE
CONVECTION OR LACK THEREOF THE PREVIOUS NIGHT. OTHERWISE THE
EXPECTATION IS THAT CLOUD COVER WILL KEEP TEMPERATURES IN CHECK A
BIT AS WILL THE THREAT FOR SHOWERS AND THUNDERSTORMS THROUGH THE
DAY. LOWS MID 50S TO LOWER 60S WITH HIGHS FROM 65 TO 70 IN SOUTHWEST
MINNESOTA TO NEAR 80 ALONG THE MISSOURI RIVER.

MONDAY THROUGH THURSDAY A VERY UNSETTLED PERIOD WITH THE WEST COAST
TROUGH MOVING INTO THE ROCKIES AND THEN POTENTIALLY ONTO THE PLAINS
LATE IN THE PERIOD. THIS ALLOWS THE GULF TO REMAIN FAIRLY OPEN AND
ANY WAVES THAT EJECT ONTO THE PLAINS WILL HAVE A GOOD CHANCE TO
PRODUCE THUNDERSTORMS. THIS MAKES IT PRETTY DIFFICULT TO PICK ANY
PERIODS OF TRULY DRY WEATHER. SO UNFORTUNATELY WILL HAVE THE CHANCE
FOR THUNDERSTORMS IN PRETTY MUCH EVERY PERIOD. AS THE TROUGH MOVES
ONTO THE PLAINS SHEAR WILL ALSO INCREASE SO THE POTENTIAL FOR SEVERE
WEATHER WILL LIKELY BE A LITTLE HIGHER WITH ANY STORMS THAT CAN
DEVELOP.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 600 PM CDT THU MAY 23 2013

VFR THROUGH 24/12Z. 24/12Z-18Z AREAS OF CEILINGS 2-3K FEET AND
VISIBILITIES 3-5SM IN SHRA/TSRA WILL DEVELOP FROM THE WEST IN THE
AREA WEST OF INTERSTATE 29. THESE WILL CONTINUE IN THIS AREA
24/18Z-25/00Z WITH CEILINGS 2-3K FEET POSSIBLY BECOMING
WIDESPREAD. NEAR AND EAST OF INTERSTATE 29 AREAS OF CEILINGS 2-3K
FEET AND VISIBILITIES 3-5SM IN SHRA/TSRA WILL DEVELOP FROM THE
WEST AFTER 24/16Z. SOUTH TO SOUTHEAST SURFACE GUSTS OF 25 TO 30
KNOTS WILL DEVELOP WEST OF INTERSTATE 29 AFTER 24/12Z. GUSTS NEAR
25 KNOTS WILL DEVELOP NEAR AND EAST OF INTERSTATE 29 AFTER 24/15Z.

&&

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

$$

SHORT TERM...JM
LONG TERM...08
AVIATION...

000
FXUS63 KFSD 232026
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
326 PM CDT THU MAY 23 2013

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 305 PM CDT THU MAY 23 2013

HIGH PRESSURE ACROSS THE REGION WILL BEGIN TO PUSH OFF TO THE EAST
OVERNIGHT...AND THE MAIN EFFECT FROM THIS WILL BE TO BRING WINDS
AROUND TO A SOUTHEASTERLY DIRECTION IN THE RETURNING SOUTHERLY LOW
LEVEL FLOW ON THE BACKSIDE OF THE HIGH. WILL SEE THE DEVELOPMENT OF
A LOW LEVEL JET OVER WESTERN SOUTH DAKOTA DURING THE NIGHT TIME
HOURS...AND THIS WILL BEGIN TO NUDGE INTO OUR FAR WEST BY FRIDAY
MORNING AS A MID LEVEL SHORTWAVE BEGINS TO TRACK OUT OF THE ROCKIES.
WITH INCREASING MIDLEVEL THETA E ADVECTION VIA THE AFOREMENTIONED
JET AND WEAK ELEVATED INSTABILITY...MAY SEE SHOWERS AND
THUNDERSTORMS DEVELOP IN OUR FAR WEST EARLY FRIDAY MORNING...THEN
PUSH TO THE EAST DURING THE DAY ON FRIDAY AS THE SHORTWAVE AND A
SURFACE WARM LIFT UP OVER THE AREA. WOULD NOT EXPECT ANY SEVERE
STORMS WITH ONLY RELATIVELY WEAK INSTABILITY IN THE MID LEVELS AND
EFFECTIVE SHEAR IN THIS AREA ONLY AROUND 15 TO 20 KTS. FRIDAY WILL
BE A BREEZY DAY WITH WINDS OF AROUND 30 KTS AT THE TOP OF THE MIXED
LAYER AND A TIGHTENING GRADIENT IN OUR WEST AS THE SURFACE LOW
PRESSURE TRACKS OUT OF THE WESTERN HIGH PLAINS. IN TERMS OF
TEMPERATURES...THERMAL PROFILES WILL BEGIN TO WARM FROM THE WEST
TONIGHT...SO WILL SEE LOWS IN THE UPPER 40S THROUGH SOUTH CENTRAL
SOUTH DAKOTA/JAMES RIVER VALLEY...TO COOLER LOWER 40S IN OUR EAST.
IN SPITE OF THE WARMING THERMAL PROFILES...FRIDAYS TEMPERATURES WILL
BE SIMILAR TO TODAY WITH THE CLOUDS AND SHOWERS...TOPPING OUT IN THE
UPPER 60S TO AROUND 70.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 305 PM CDT THU MAY 23 2013

FRIDAY NIGHT IS A BIT OF A MESS TO DECIPHER THROUGH THE MODELS. AN
ELEVATED BAND OF RAIN AND THUNDERSTORMS WILL LIKELY EXIT THE EASTERN
CWA DURING THE EVENING ASSOCIATED WITH SOMETHING CLOSE TO THE
700-750MB LAYER. FROM ABOUT 3Z THROUGH 6Z THE LOW LEVEL JET WILL
CRANK UP AT ABOUT 850MB AND MAY ALLOW FOR MORE THUNDERSTORMS TO
DEVELOP AROUND THE MISSOURI RIVER AND TRACK EASTWARD AND LIKELY
TRACK INTO NORTHWEST IOWA. THE INITIAL ELEVATED BAND WILL LIKELY NOT
HAVE QUITE ENOUGH INSTABILITY OR SHEAR TO PRODUCE ANY SEVERE WEATHER
BUT THE SECOND AREA OF DEVELOPMENT MAY SEE CAP VALUES AROUND 1500
J/KG SO NOT OUT OF THE QUESTION TO PRODUCE SOME HAIL...ESPECIALLY
WITH ABOUT 30 TO 40 KNOTS OF SHEAR. THE FREEZING LEVEL IS AT ABOUT
11000 FEET SO PRETTY AVERAGE FOR THIS TIME OF YEAR. AN INTERESTING
NOTE...THE NAM BUFKIT SOUNDINGS ARE NOT MATCHING UP WITH THE NAM
PLAN VIEW OUTPUT IN AWIPS...RESULTING IN PRETTY BIG DIFFERENCES IN
SHEAR VALUES.

THE SET UP SATURDAY INTO SATURDAY NIGHT MAY POSE A THREAT FOR SEVERE
WEATHER AND POSSIBLY SOME HEAVY RAINFALL. WHILE UPPER LEVEL FLOW ON
THE LATEST RUNS OF THE MODELS HAS INCREASED A BIT...WHICH IS WHAT
BRINGS MORE OF A THREAT FOR SEVERE WEATHER WITH 0 TO 6KM BULK SHEAR
ABOUT 40 TO 45 KNOTS AND A FAIRLY STRONG CAPE GRADIENT ALONG THE
MISSOURI RIVER VALLEY WITH 2500 J/KG CAPES TO THE SOUTH OF THE
BOUNDARY. WHAT ALSO MAKES THIS AN INTERESTING SET UP IS THAT THE
TIMING OF THE WAVE ALLOWS FOR AN INCREASING LOW LEVEL JET THROUGH
THE EVENING SO IF STORMS CAN DEVELOP LATE AFTERNOON ALONG AND
NORTH OF THE BOUNDARY THERE SHOULD BE A STEADY OR INCREASING FEED OF
DEEPER MOISTURE AND BETTER INSTABILITY. RIGHT NOW SURFACE BASED
THUNDERSTORMS APPEAR UNLIKELY WITH A FAIRLY SIGNIFICANT CAP SO
BELIEVE ANY THUNDERSTORMS THAT CAN DEVELOP NORTH OF THE MISSOURI
RIVER WILL BE ELEVATED SO HAIL AND HEAVY RAIN WILL BE THE MAIN
THREATS.

BY SUNDAY THE THREAT FOR THUNDERSTORMS WILL CONTINUE AS BOUNDARY
LOOKS TO LINGER AROUND. WHILE INSTABILITY MAY STILL BE FAIRLY HIGH
AROUND 2000 J/KG IN THE SOUTHERN CWA SHEAR LOOKS TO DROP OFF
CONSIDERABLY. KIND OF A WAIT AND SEE FOR THIS DAY AS WITH CONVECTION
MANY TIMES THE BOUNDARY LOCATIONS WILL BE DEPENDENT UPON THE
CONVECTION OR LACK THEREOF THE PREVIOUS NIGHT. OTHERWISE THE
EXPECTATION IS THAT CLOUD COVER WILL KEEP TEMPERATURES IN CHECK A
BIT AS WILL THE THREAT FOR SHOWERS AND THUNDERSTORMS THROUGH THE
DAY. LOWS MID 50S TO LOWER 60S WITH HIGHS FROM 65 TO 70 IN SOUTHWEST
MINNESOTA TO NEAR 80 ALONG THE MISSOURI RIVER.

MONDAY THROUGH THURSDAY A VERY UNSETTLED PERIOD WITH THE WEST COAST
TROUGH MOVING INTO THE ROCKIES AND THEN POTENTIALLY ONTO THE PLAINS
LATE IN THE PERIOD. THIS ALLOWS THE GULF TO REMAIN FAIRLY OPEN AND
ANY WAVES THAT EJECT ONTO THE PLAINS WILL HAVE A GOOD CHANCE TO
PRODUCE THUNDERSTORMS. THIS MAKES IT PRETTY DIFFICULT TO PICK ANY
PERIODS OF TRULY DRY WEATHER. SO UNFORTUNATELY WILL HAVE THE CHANCE
FOR THUNDERSTORMS IN PRETTY MUCH EVERY PERIOD. AS THE TROUGH MOVES
ONTO THE PLAINS SHEAR WILL ALSO INCREASE SO THE POTENTIAL FOR SEVERE
WEATHER WILL LIKELY BE A LITTLE HIGHER WITH ANY STORMS THAT CAN
DEVELOP.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1216 PM CDT THU MAY 23 2013

VFR CONDITIONS WILL PREDOMINATE THROUGH THE TAF PERIOD. INCREASING
SOUTHEASTERLY WINDS ALOFT WILL RESULT IN LOW LEVEL WIND SHEAR AT
KHON LATER TONIGHT. SHOWERS AND THUNDERSTORMS WILL DEVELOP THROUGH
THE JAMES RIVER VALLEY ON FRIDAY MORNING...AND SOUTHEASTERLY WINDS
WILL PICK UP ACROSS THE ENTIRE AREA...GUSTING TO 25 KTS AT TIMES.

&&

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

$$

SHORT TERM...JM
LONG TERM...08
AVIATION...JM

000
FXUS63 KFSD 231720
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1220 PM CDT THU MAY 23 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT THU MAY 23 2013

LIKELY THE BEST DAY OF THE NEXT MANY DAYS WILL OCCUR ACROSS THE
AREA TODAY WITH SHARP RIDGE ALOFT ACROSS THE AREA. EASTERLY TO
NORTHEAST TRAJECTORY OUT OF KEEWATIN HIGH WILL CONTINUE TO INTRODUCE
DRIER AIR AT LOWER LEVELS.  FLOW IS QUITE ANTICYCLONIC AND OVERALL
LARGER SCALE QUITE SUBSIDENT. RECENT PRECIPITATION HAS SATURATED UP
THE SURFACE QUITE A BIT...AND WITH HEATING AND BUILDING OF MIXED
LAYER WOULD EXPECT POTENTIAL FOR A BIT OF FLAT CUMULUS DEVELOPMENT.
LIKELY SOMEWHAT TERRAIN TIED. LARGE SCALE AND ANTICYCLONIC FLOW
SHOULD KEEP CLOUDS FROM GAINING A GREAT DEAL OF DIURNAL COVERAGE...
PROBABLY AN EARLY TO MID  AFTERNOON MAXIMUM IN THE SCATTERED
COVERAGE REALM. GOOD RECOVERY TO TEMPS WITH SUNSHINE TODAY...
MIXING TO MID 60S TO AROUND 70.

PRESSURE GRADIENT GRADUALLY INCREASES ACROSS THE AREA THROUGH THE
OVERNIGHT AS SURFACE RIDGE RETREATS TO THE EAST. RELATIVELY DRY
AIRMASS ACROSS THE AREA SHOULD LEAD TO COOL OVERNIGHT LOWS...WITH
THE COOLEST READINGS IN THE EASTERN CWA WHERE WINDS AND INCREASING
CLOUDS WILL BE LESS OF A FACTOR.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 340 AM CDT THU MAY 23 2013

MODELS INDICATE STRONG MOISTURE TRANSPORT IN THE MID LEVELS ON
FRIDAY LEADING TO ELEVATED CONVECTIVE POTENTIAL AS ISENTROPIC LIFT
INCREASES THROUGHOUT THE DAY. MODEL SOUNDINGS INDICATE TALL THIN
CAPE PROFILE...AND WITH RELATIVELY WEAK WIND SHEAR...AM NOT
EXPECTING MUCH IN THE WAY OF SEVERE POTENTIAL. BAND APPEARS TO
GRADUALLY SHIFT TO THE EAST FRIDAY NIGHT...WITH CONVECTIVE
POTENTIAL REORGANIZING TO THE SOUTH AS BETTER INSTABILITY AND
MOISTURE ORGANIZES TO THE SOUTH. MODELS INDICATE WARM FRONT
HANGING ACROSS THE AREA THROUGH THE WEEKEND...MAKING CONVECTION
DIFFICULT TO TIME. AM NOT THINKING THE WEEKEND WILL BE AN ENTIRE
WASHOUT...BUT INSTEAD PERIODIC RAIN CHANCES FAVORING A DIURNAL
TREND. SLIGHTLY BETTER SEVERE POTENTIAL EXISTS ON SATURDAY INTO
SUNDAY...HOWEVER...REALTIVELY WEAK WIND SHEAR SHOULD KEEP SEVERE
POTENTIAL FAIRLY ISOLATED. CONVECTION CHANCES APPEAR TO BE FAIRLY
GOOD SATURDAY NIGHT AS LOW LEVEL JET INCREASES ACROSS THE PLAINS
AND HAVE RAISED POPS SOME OVER GUIDANCE.

FORECAST BECOMES QUITE MUDDY BEYOND SATURDAY NIGHT WITH SHORTWAVES
EMBEDDED IN WEST TO SOUTHWEST FLOW ALOFT. MODELS IN GENERAL SUGGEST
AN ACTIVE PATTERN...WITH EACH OFFERING THEIR OWN FLAVOR ON TIMING
AND LOCATION OF POPS. IN GENERAL...KEPT CHANCE POPS THROUGH THE
PERIOD. IN TERMS OF TEMPERATURES...KEPT TEMPERATURES VERY SIMILAR
TO THE PREVIOUS FORECAST...HOWEVER...OPERATIONAL RUN OF GFS IS
ERRING TOWARDS THE WARMER SIDE OF THE ENSEMBLE...POTENTIALLY
SUGGESTING OPTIMISTIC FORECAST HIGHS FOR THE HOLIDAY WEEKEND INTO

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1216 PM CDT THU MAY 23 2013

VFR CONDITIONS WILL PREDOMINATE THROUGH THE TAF PERIOD. INCREASING
SOUTHEASTERLY WINDS ALOFT WILL RESULT IN LOW LEVEL WIND SHEAR AT
KHON LATER TONIGHT. SHOWERS AND THUNDERSTORMS WILL DEVELOP THROUGH
THE JAMES RIVER VALLEY ON FRIDAY MORNING...AND SOUTHEASTERLY WINDS
WILL PICK UP ACROSS THE ENTIRE AREA...GUSTING TO 25 KTS AT TIMES.

&&

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

$$

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

000
FXUS63 KFSD 231139
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
639 AM CDT THU MAY 23 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT THU MAY 23 2013

LIKELY THE BEST DAY OF THE NEXT MANY DAYS WILL OCCUR ACROSS THE
AREA TODAY WITH SHARP RIDGE ALOFT ACROSS THE AREA. EASTERLY TO
NORTHEAST TRAJECTORY OUT OF KEEWATIN HIGH WILL CONTINUE TO INTRODUCE
DRIER AIR AT LOWER LEVELS.  FLOW IS QUITE ANTICYCLONIC AND OVERALL
LARGER SCALE QUITE SUBSIDENT. RECENT PRECIPITATION HAS SATURATED UP
THE SURFACE QUITE A BIT...AND WITH HEATING AND BUILDING OF MIXED
LAYER WOULD EXPECT POTENTIAL FOR A BIT OF FLAT CUMULUS DEVELOPMENT.
LIKELY SOMEWHAT TERRAIN TIED. LARGE SCALE AND ANTICYCLONIC FLOW
SHOULD KEEP CLOUDS FROM GAINING A GREAT DEAL OF DIURNAL COVERAGE...
PROBABLY AN EARLY TO MID  AFTERNOON MAXIMUM IN THE SCATTERED
COVERAGE REALM. GOOD RECOVERY TO TEMPS WITH SUNSHINE TODAY...
MIXING TO MID 60S TO AROUND 70.

PRESSURE GRADIENT GRADUALLY INCREASES ACROSS THE AREA THROUGH THE
OVERNIGHT AS SURFACE RIDGE RETREATS TO THE EAST. RELATIVELY DRY
AIRMASS ACROSS THE AREA SHOULD LEAD TO COOL OVERNIGHT LOWS...WITH
THE COOLEST READINGS IN THE EASTERN CWA WHERE WINDS AND INCREASING
CLOUDS WILL BE LESS OF A FACTOR.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 340 AM CDT THU MAY 23 2013

MODELS INDICATE STRONG MOISTURE TRANSPORT IN THE MID LEVELS ON
FRIDAY LEADING TO ELEVATED CONVECTIVE POTENTIAL AS ISENTROPIC LIFT
INCREASES THROUGHOUT THE DAY. MODEL SOUNDINGS INDICATE TALL THIN
CAPE PROFILE...AND WITH RELATIVELY WEAK WIND SHEAR...AM NOT
EXPECTING MUCH IN THE WAY OF SEVERE POTENTIAL. BAND APPEARS TO
GRADUALLY SHIFT TO THE EAST FRIDAY NIGHT...WITH CONVECTIVE
POTENTIAL REORGANIZING TO THE SOUTH AS BETTER INSTABILITY AND
MOISTURE ORGANIZES TO THE SOUTH. MODELS INDICATE WARM FRONT
HANGING ACROSS THE AREA THROUGH THE WEEKEND...MAKING CONVECTION
DIFFICULT TO TIME. AM NOT THINKING THE WEEKEND WILL BE AN ENTIRE
WASHOUT...BUT INSTEAD PERIODIC RAIN CHANCES FAVORING A DIURNAL
TREND. SLIGHTLY BETTER SEVERE POTENTIAL EXISTS ON SATURDAY INTO
SUNDAY...HOWEVER...REALTIVELY WEAK WIND SHEAR SHOULD KEEP SEVERE
POTENTIAL FAIRLY ISOLATED. CONVECTION CHANCES APPEAR TO BE FAIRLY
GOOD SATURDAY NIGHT AS LOW LEVEL JET INCREASES ACROSS THE PLAINS
AND HAVE RAISED POPS SOME OVER GUIDANCE.

FORECAST BECOMES QUITE MUDDY BEYOND SATURDAY NIGHT WITH SHORTWAVES
EMBEDDED IN WEST TO SOUTHWEST FLOW ALOFT. MODELS IN GENERAL SUGGEST
AN ACTIVE PATTERN...WITH EACH OFFERING THEIR OWN FLAVOR ON TIMING
AND LOCATION OF POPS. IN GENERAL...KEPT CHANCE POPS THROUGH THE
PERIOD. IN TERMS OF TEMPERATURES...KEPT TEMPERATURES VERY SIMILAR
TO THE PREVIOUS FORECAST...HOWEVER...OPERATIONAL RUN OF GFS IS
ERRING TOWARDS THE WARMER SIDE OF THE ENSEMBLE...POTENTIALLY
SUGGESTING OPTIMISTIC FORECAST HIGHS FOR THE HOLIDAY WEEKEND INTO

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 638 AM CDT THU MAY 23 2013

WEBCAM AT HURON AIRPORT REVEALS THAT AUTOMATED OBSERVATION HAS
GENERALLY BEEN WELL OFF THIS MORNING...INDICATING AS LOW AS 1/4SM
VISIBILITY AND A 100 FT AGL CEILING AT TIMES...WHEN MUCH LESS
STRICT CONDITIONS HAVE BEEN IN PLAY. AS A RESULT...HAVE WRITTEN
A MUCH MORE OPTIMISTIC TAF FOR KHON...WITH SHALLOW MOISTURE IN
FORECAST SOUNDINGS SUPPORTIVE OF THE FUZZY 3-5SM VISIBILITY
APPARENTLY PRESENT. OTHERWISE...HAVE SOME MVFR CEILINGS ON VERGE
OF EXITING KSUX AREA BY 12Z...AND THIS WILL LEAD TO OVERALL VFR
CONDITIONS THROUGH REMAINDER OF PERIOD. SOME LOW END VFR CLOUDS
WILL DEVELOP AROUND MIDDAY HOURS.  AS SOUTHERLY GRADIENT ALOFT
INCREASES...KHON WILL LIKELY DEVELOP SOME LOW LEVEL WIND SHEAR
CONDITIONS AFTER 06Z.

&&

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

$$

SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...CHAPMAN

000
FXUS63 KFSD 230917
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
417 AM CDT THU MAY 23 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT THU MAY 23 2013

LIKELY THE BEST DAY OF THE NEXT MANY DAYS WILL OCCUR ACROSS THE
AREA TODAY WITH SHARP RIDGE ALOFT ACROSS THE AREA. EASTERLY TO
NORTHEAST TRAJECTORY OUT OF KEEWATIN HIGH WILL CONTINUE TO INTRODUCE
DRIER AIR AT LOWER LEVELS.  FLOW IS QUITE ANTICYCLONIC AND OVERALL
LARGER SCALE QUITE SUBSIDENT. RECENT PRECIPITATION HAS SATURATED UP
THE SURFACE QUITE A BIT...AND WITH HEATING AND BUILDING OF MIXED
LAYER WOULD EXPECT POTENTIAL FOR A BIT OF FLAT CUMULUS DEVELOPMENT.
LIKELY SOMEWHAT TERRAIN TIED. LARGE SCALE AND ANTICYCLONIC FLOW
SHOULD KEEP CLOUDS FROM GAINING A GREAT DEAL OF DIURNAL COVERAGE...
PROBABLY AN EARLY TO MID  AFTERNOON MAXIMUM IN THE SCATTERED
COVERAGE REALM. GOOD RECOVERY TO TEMPS WITH SUNSHINE TODAY...
MIXING TO MID 60S TO AROUND 70.

PRESSURE GRADIENT GRADUALLY INCREASES ACROSS THE AREA THROUGH THE
OVERNIGHT AS SURFACE RIDGE RETREATS TO THE EAST. RELATIVELY DRY
AIRMASS ACROSS THE AREA SHOULD LEAD TO COOL OVERNIGHT LOWS...WITH
THE COOLEST READINGS IN THE EASTERN CWA WHERE WINDS AND INCREASING
CLOUDS WILL BE LESS OF A FACTOR.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 340 AM CDT THU MAY 23 2013

MODELS INDICATE STRONG MOISTURE TRANSPORT IN THE MID LEVELS ON
FRIDAY LEADING TO ELEVATED CONVECTIVE POTENTIAL AS ISENTROPIC LIFT
INCREASES THROUGHOUT THE DAY. MODEL SOUNDINGS INDICATE TALL THIN
CAPE PROFILE...AND WITH RELATIVELY WEAK WIND SHEAR...AM NOT
EXPECTING MUCH IN THE WAY OF SEVERE POTENTIAL. BAND APPEARS TO
GRADUALLY SHIFT TO THE EAST FRIDAY NIGHT...WITH CONVECTIVE
POTENTIAL REORGANIZING TO THE SOUTH AS BETTER INSTABILITY AND
MOISTURE ORGANIZES TO THE SOUTH. MODELS INDICATE WARM FRONT
HANGING ACROSS THE AREA THROUGH THE WEEKEND...MAKING CONVECTION
DIFFICULT TO TIME. AM NOT THINKING THE WEEKEND WILL BE AN ENTIRE
WASHOUT...BUT INSTEAD PERIODIC RAIN CHANCES FAVORING A DIURNAL
TREND. SLIGHTLY BETTER SEVERE POTENTIAL EXISTS ON SATURDAY INTO
SUNDAY...HOWEVER...REALTIVELY WEAK WIND SHEAR SHOULD KEEP SEVERE
POTENTIAL FAIRLY ISOLATED. CONVECTION CHANCES APPEAR TO BE FAIRLY
GOOD SATURDAY NIGHT AS LOW LEVEL JET INCREASES ACROSS THE PLAINS
AND HAVE RAISED POPS SOME OVER GUIDANCE.

FORECAST BECOMES QUITE MUDDY BEYOND SATURDAY NIGHT WITH SHORTWAVES
EMBEDDED IN WEST TO SOUTHWEST FLOW ALOFT. MODELS IN GENERAL SUGGEST
AN ACTIVE PATTERN...WITH EACH OFFERING THEIR OWN FLAVOR ON TIMING
AND LOCATION OF POPS. IN GENERAL...KEPT CHANCE POPS THROUGH THE
PERIOD. IN TERMS OF TEMPERATURES...KEPT TEMPERATURES VERY SIMILAR
TO THE PREVIOUS FORECAST...HOWEVER...OPERATIONAL RUN OF GFS IS
ERRING TOWARDS THE WARMER SIDE OF THE ENSEMBLE...POTENTIALLY
SUGGESTING OPTIMISTIC FORECAST HIGHS FOR THE HOLIDAY WEEKEND INTO
EARLY NEXT WEEK.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1023 PM CDT WED MAY 22 2013

VFR CONDITIONS WILL CONTINUE TO PRESS SOUTHWARD ACROSS THE SIOUX
FALLS FORECAST AREA FOR THE REST OF TONIGHT. BEFORE THE
CLEARING HOWEVER...EXPECT WIDESPREAD MVFR TO UPPER END IFR
CEILINGS. IN ADDITION...A SURFACE RIDGE AXIS WILL SETUP EXTENDING
FROM CENTRAL SOUTH DAKOTA TO NORTHEAST SOUTH DAKOTA. BECAUSE OF
THIS...THE WINDS WILL GO PRETTY LIGHT IN OUR NORTHWEST ZONES...
INCLUDING THE KHON TAF SITE...WHICH COULD SETUP SOME MVFR TO IFR
FOG AROUND SUNRISE IN THAT LOCATION OVER THE WET GROUND. THURSDAY
WILL ALSO BE VFR...BUT SOME STRATOCUMULUS CLOUDS COULD FORM IN THE
MIDDLE OF THE DAY CAUSING SOME BROKEN CEILINGS...STILL IN THE
LOWER VFR CATEGORY.


&&

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

$$

SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...

000
FXUS63 KFSD 230324
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1024 PM CDT WED MAY 22 2013

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 305 PM CDT WED MAY 22 2013

UPPER LOW FINALLY DEPARTING THE REGION TO THE SOUTHEAST AND
CURRENTLY LOCATED OVER THE IA/MN/WI STATE LINES PER WATER VAPOR
IMAGERY. HOWEVER...A VORT MAX ON THE WEST SIDE OF THE LOW /CURRENTLY
OVER THE TRI-STATE AREA/ WILL CONTINUE TO GENERATE SHOWERS THIS
AFTERNOON/EVENING...SLOWLY ENDING FROM WEST TO EAST AS THE UPPER LOW
AND VORT MAX BOTH SINK SOUTHEAST. NO FOCUSED MESOSCALE FORCING LOOKS
PRESENT...AS SHOWERS ARE SYNOPTICALLY DRIVEN...SO ONLY LIGHT SHOWERS
ARE EXPECTED THROUGH THIS AFTERNOON/EARLY EVENING.
OVERNIGHT...AIRMASS DRYING WORKS FROM MID/UPPER LEVELS DOWN AND
ADVECTS SOUTH ACROSS THE FORECAST AREA. LOW LEVEL WINDS WILL VEER TO
EAST-NORTHEAST AS TROUGH MOVES SOUTHWARD. THIS WINDS DIRECTION
TYPICAL FAVORS LINGERING MOISTURE/STRATUS...HOWEVER...WITH SUCH
EXTRAORDINARY DRY AIRMASS IN MID-LEVELS/AS SEEN ON WATER VAPOR OVER
ND AND NW MN/...EXPECT THAT SCOURING OUT THE STRATUS SHOULD NOT BE
AN ISSUE. LIGHT WINDS AND RECENT RAINS WILL LIKELY RESULT IN SOME
RADIATIONAL FOG LATE TONIGHT WHERE CLEARING OCCURS FIRST...AND HAVE
EXPANDED FOG COVERAGE FOR LATE TONIGHT ACROSS THE AREA. AFTER A COOL
NIGHT...TEMPERATURES WILL BEGIN TO REBOUND THURSDAY AS UPPER RIDGING
AMPLIFIES AND WARM AIR ADVECTION SETS IN FOR THE AFTERNOON. WILL
ALSO HAVE PLENTY OF SUNSHINE /MAYBE A FEW CU/ AND A DRY AIRMASS IN
PLACE AS HIGH PRESSURE AXIS BUILDS ACROSS THE UPPER MIDWEST. H85
TEMPS INCREASE TO 5 TO 10 C FROM EAST TO WEST ACROSS THE FORECAST
AREA BY 00Z FRIDAY. DESPITE THIS WARM-UP...TEMPS STILL WILL AVERAGE
NEARLY 5 DEGREES BELOW NORMAL FOR HIGHS THURSDAY.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED MAY 22 2013

FRIDAY WILL SEE A HUGE CHANGEOVER ALOFT AS DEW POINTS AROUND 700MB
AT ABOUT -40 DEGREES C THURSDAY NIGHT WILL INCREASE TO ABOUT +5
DEGREES C BY FRIDAYS AFTERNOON. WITH 700MB TO 500MB LAPSE RATES ALSO
RUNNING ABOUT 7 DEGREES OR SO...A BIT TOUGH TO GAGE AS
PRECIPITATION BREAKS OUT IN THE MODEL...THERE SHOULD BE A DECENT
CHANCE FOR AN ELEVATED BAND OF SHOWERS AND THUNDERSTORMS TO DEVELOP.
WILL CONTINUE WITH SOME MID RANGE POPS BUT MAYBE INCREASE JUST A
BIT. ELEVATED CAPE FROM AROUND 750MB TO 700MB RUNNING ABOUT 500 TO
700 J/KG WHICH SUPPORTS THUNDER CHANCES.

SATURDAY LOOKS LIKE A BIT OF A BREEZY DAY AS A WARM FRONT BECOMES
ESTABLISHED OVER THE SOUTHERN CWA INTO PARTS OF NORTHERN NEBRASKA. A
DECENT AMOUNT OF INSTABILITY LOW LEVEL SHEAR EXISTS BUT WINDS ALOFT
NOT VERY SUPPORTIVE OF ORGANIZED CONVECTION. NOT TO MENTION CAPPING
LOOKS PRETTY STRONG AND CONVECTION WILL LIKELY NEED TO DEVELOP
OUTSIDE OF THE AREA AND ADVECT IN. WILL DECREASE POPS A IT ON THE
NORTH THINKING CAPPING WILL HAVE EVERYTHING SHUT DOWN.

NO EASY ANSWERS FOR SUNDAY INTO WEDNESDAY AS A BOUNDARY LOOKS TO
LINGER AROUND MUCH OF THE TIME. RELATIVELY WEAK UPPER LEVEL FLOW
SHOULD PRECLUDE ANY MAJOR SEVERE WEATHER OUTBREAKS SUNDAY INTO
MONDAY BUT ENOUGH LOW LEVEL SHEAR AND INSTABILITY TO PROMOTE THE
POSSIBILITY FOR A FEW SEVERE STORMS. AS WE MOVE INTO TUESDAY AND
WEDNESDAY THE MODELS BEGIN TO SHIFT THE FASTER SOUTHWEST FLOW ALOFT
ONTO THE NORTHERN AND CENTRAL PLAINS WHICH IF WE STILL HAVE A
BOUNDARY AROUND THERE MAY BE A BETTER CHANCE FOR SEVERE
THUNDERSTORMS WITH DEEPER ENHANCED SHEAR. OTHERWISE...THE ECMWF
CONTINUES TO LOCK IN THE COOLER AIR SUNDAY AND MONDAY MORE SO THAN
THE GFS AND GEM. TUESDAY AND WEDNESDAY WILL SEE A BETTER CHANCE FOR
WARMER CONDITIONS AND WITH THE LOW LEVEL RIDGE IN THE SOUTH
SHIFTING EAST THE GULF OPENS UP A LOT MORE AND DEEPER MOISTURE WILL
LIKELY EXIST. WILL UNFORTUNATELY HAVE POPS IN EVERY DAY BUT LEANING
TOWARDS BETTER CHANCES SOUTH SUNDAY AND MONDAY THEN ANYWHERE TUESDAY
AND WEDNESDAY...MAYBE A LITTLE BETTER IN THE EASTERN TWO THIRDS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1023 PM CDT WED MAY 22 2013

VFR CONDITIONS WILL CONTINUE TO PRESS SOUTHWARD ACROSS THE SIOUX
FALLS FORECAST AREA FOR THE REST OF TONIGHT. BEFORE THE
CLEARING HOWEVER...EXPECT WIDESPREAD MVFR TO UPPER END IFR
CEILINGS. IN ADDITION...A SURFACE RIDGE AXIS WILL SETUP EXTENDING
FROM CENTRAL SOUTH DAKOTA TO NORTHEAST SOUTH DAKOTA. BECAUSE OF
THIS...THE WINDS WILL GO PRETTY LIGHT IN OUR NORTHWEST ZONES...
INCLUDING THE KHON TAF SITE...WHICH COULD SETUP SOME MVFR TO IFR
FOG AROUND SUNRISE IN THAT LOCATION OVER THE WET GROUND. THURSDAY
WILL ALSO BE VFR...BUT SOME STRATOCUMULUS CLOUDS COULD FORM IN THE
MIDDLE OF THE DAY CAUSING SOME BROKEN CEILINGS...STILL IN THE
LOWER VFR CATEGORY.

&&

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

$$

SHORT TERM...
LONG TERM...08
AVIATION...

000
FXUS63 KFSD 222331
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
631 PM CDT WED MAY 22 2013

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 305 PM CDT WED MAY 22 2013

UPPER LOW FINALLY DEPARTING THE REGION TO THE SOUTHEAST AND
CURRENTLY LOCATED OVER THE IA/MN/WI STATE LINES PER WATER VAPOR
IMAGERY. HOWEVER...A VORT MAX ON THE WEST SIDE OF THE LOW /CURRENTLY
OVER THE TRI-STATE AREA/ WILL CONTINUE TO GENERATE SHOWERS THIS
AFTERNOON/EVENING...SLOWLY ENDING FROM WEST TO EAST AS THE UPPER LOW
AND VORT MAX BOTH SINK SOUTHEAST. NO FOCUSED MESOSCALE FORCING LOOKS
PRESENT...AS SHOWERS ARE SYNOPTICALLY DRIVEN...SO ONLY LIGHT SHOWERS
ARE EXPECTED THROUGH THIS AFTERNOON/EARLY EVENING.
OVERNIGHT...AIRMASS DRYING WORKS FROM MID/UPPER LEVELS DOWN AND
ADVECTS SOUTH ACROSS THE FORECAST AREA. LOW LEVEL WINDS WILL VEER TO
EAST-NORTHEAST AS TROUGH MOVES SOUTHWARD. THIS WINDS DIRECTION
TYPICAL FAVORS LINGERING MOISTURE/STRATUS...HOWEVER...WITH SUCH
EXTRAORDINARY DRY AIRMASS IN MID-LEVELS/AS SEEN ON WATER VAPOR OVER
ND AND NW MN/...EXPECT THAT SCOURING OUT THE STRATUS SHOULD NOT BE
AN ISSUE. LIGHT WINDS AND RECENT RAINS WILL LIKELY RESULT IN SOME
RADIATIONAL FOG LATE TONIGHT WHERE CLEARING OCCURS FIRST...AND HAVE
EXPANDED FOG COVERAGE FOR LATE TONIGHT ACROSS THE AREA. AFTER A COOL
NIGHT...TEMPERATURES WILL BEGIN TO REBOUND THURSDAY AS UPPER RIDGING
AMPLIFIES AND WARM AIR ADVECTION SETS IN FOR THE AFTERNOON. WILL
ALSO HAVE PLENTY OF SUNSHINE /MAYBE A FEW CU/ AND A DRY AIRMASS IN
PLACE AS HIGH PRESSURE AXIS BUILDS ACROSS THE UPPER MIDWEST. H85
TEMPS INCREASE TO 5 TO 10 C FROM EAST TO WEST ACROSS THE FORECAST
AREA BY 00Z FRIDAY. DESPITE THIS WARM-UP...TEMPS STILL WILL AVERAGE
NEARLY 5 DEGREES BELOW NORMAL FOR HIGHS THURSDAY.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED MAY 22 2013

FRIDAY WILL SEE A HUGE CHANGEOVER ALOFT AS DEW POINTS AROUND 700MB
AT ABOUT -40 DEGREES C THURSDAY NIGHT WILL INCREASE TO ABOUT +5
DEGREES C BY FRIDAYS AFTERNOON. WITH 700MB TO 500MB LAPSE RATES ALSO
RUNNING ABOUT 7 DEGREES OR SO...A BIT TOUGH TO GAUGE AS
PRECIPITATION BREAKS OUT IN THE MODEL...THERE SHOULD BE A DECENT
CHANCE FOR AN ELEVATED BAND OF SHOWERS AND THUNDERSTORMS TO DEVELOP.
WILL CONTINUE WITH SOME MID RANGE POPS BUT MAYBE INCREASE JUST A
BIT. ELEVATED CAPE FROM AROUND 750MB TO 700MB RUNNING ABOUT 500 TO
700 J/KG WHICH SUPPORTS THUNDER CHANCES.

SATURDAY LOOKS LIKE A BIT OF A BREEZY DAY AS A WARM FRONT BECOMES
ESTABLISHED OVER THE SOUTHERN CWA INTO PARTS OF NORTHERN NEBRASKA. A
DECENT AMOUNT OF INSTABILITY LOW LEVEL SHEAR EXISTS BUT WINDS ALOFT
NOT VERY SUPPORTIVE OF ORGANIZED CONVECTION. NOT TO MENTION CAPPING
LOOKS PRETTY STRONG AND CONVECTION WILL LIKELY NEED TO DEVELOP
OUTSIDE OF THE AREA AND ADVECT IN. WILL DECREASE POPS A IT ON THE
NORTH THINKING CAPPING WILL HAVE EVERYTHING SHUT DOWN.

NO EASY ANSWERS FOR SUNDAY INTO WEDNESDAY AS A BOUNDARY LOOKS TO
LINGER AROUND MUCH OF THE TIME. RELATIVELY WEAK UPPER LEVEL FLOW
SHOULD PRECLUDE ANY MAJOR SEVERE WEATHER OUTBREAKS SUNDAY INTO
MONDAY BUT ENOUGH LOW LEVEL SHEAR AND INSTABILITY TO PROMOTE THE
POSSIBILITY FOR A FEW SEVERE STORMS. AS WE MOVE INTO TUESDAY AND
WEDNESDAY THE MODELS BEGIN TO SHIFT THE FASTER SOUTHWEST FLOW ALOFT
ONTO THE NORTHERN AND CENTRAL PLAINS WHICH IF WE STILL HAVE A
BOUNDARY AROUND THERE MAY BE A BETTER CHANCE FOR SEVERE
THUNDERSTORMS WITH DEEPER ENHANCED SHEAR. OTHERWISE...THE ECMWF
CONTINUES TO LOCK IN THE COOLER AIR SUNDAY AND MONDAY MORE SO THAN
THE GFS AND GEM. TUESDAY AND WEDNESDAY WILL SEE A BETTER CHANCE FOR
WARMER CONDITIONS AND WITH THE LOW LEVEL RIDGE IN THE SOUTH
SHIFTING EAST THE GULF OPENS UP A LOT MORE AND DEEPER MOISTURE WILL
LIKELY EXIST. WILL UNFORTUNATELY HAVE POPS IN EVERY DAY BUT LEANING
TOWARDS BETTER CHANCES SOUTH SUNDAY AND MONDAY THEN ANYWHERE TUESDAY
AND WEDNESDAY...MAYBE A LITTLE BETTER IN THE EASTERN TWO THIRDS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 630 PM CDT WED MAY 22 2013

MVFR CONDITIONS WITH SOME LOCALIZED IFR WILL GRADUALLY ERODE
SOUTHWARD THROUGH TONIGHT. BEHIND THE STRATUS...VFR CONDITIONS
SHOULD TAKE HOLD BUT THERE IS ONE CAVEAT. A SURFACE HIGH PRESSURE
RIDGE AXIS WILL EXTEND FROM CENTRAL SD TO CENTRAL MN BY LATE
TONIGHT AND EARLY THURSDAY. THEREFORE THE WINDS WILL LIKELY GO
VERY LIGHT IN OUR NORTHWEST ZONES INCLUDING THE KHON TAF. WITH THE
MOIST GROUND...AM WORRIED ABOUT FOG POTENTIAL LATE TONIGHT AND
EARLY THURSDAY FOR THOSE AREAS...SO KEPT THE MENTION OF SOME IFR
VISIBILITIES FOR KHON. OTHERWISE VFR SHOULD PREVAIL FOR MOST AREAS
ON THURSDAY. WOULD NOT BE SURPRISED TO SEE SOME SCATTERED TO
BROKEN CEILINGS FROM EVAPORATION OFF OF WET GROUND IN THE LATE
MORNING AND AFTERNOON. BUT LATEST NAM MODEL SOUNDINGS SHOW THAT
ANY BROKEN CEILINGS SHOULD BE IN THE LOWER VFR CATEGORY.

&&

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

$$

SHORT TERM...
LONG TERM...08
AVIATION...MJF

000
FXUS63 KFSD 222007
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
307 PM CDT WED MAY 22 2013

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 305 PM CDT WED MAY 22 2013

UPPER LOW FINALLY DEPARTING THE REGION TO THE SOUTHEAST AND
CURRENTLY LOCATED OVER THE IA/MN/WI STATE LINES PER WATER VAPOR
IMAGERY. HOWEVER...A VORT MAX ON THE WEST SIDE OF THE LOW /CURRENTLY
OVER THE TRI-STATE AREA/ WILL CONTINUE TO GENERATE SHOWERS THIS
AFTERNOON/EVENING...SLOWLY ENDING FROM WEST TO EAST AS THE UPPER LOW
AND VORT MAX BOTH SINK SOUTHEAST. NO FOCUSED MESOSCALE FORCING LOOKS
PRESENT...AS SHOWERS ARE SYNOPTICALLY DRIVEN...SO ONLY LIGHT SHOWERS
ARE EXPECTED THROUGH THIS AFTERNOON/EARLY EVENING.
OVERNIGHT...AIRMASS DRYING WORKS FROM MID/UPPER LEVELS DOWN AND
ADVECTS SOUTH ACROSS THE FORECAST AREA. LOW LEVEL WINDS WILL VEER TO
EAST-NORTHEAST AS TROUGH MOVES SOUTHWARD. THIS WINDS DIRECTION
TYPICAL FAVORS LINGERING MOISTURE/STRATUS...HOWEVER...WITH SUCH
EXTRAORDINARY DRY AIRMASS IN MID-LEVELS/AS SEEN ON WATER VAPOR OVER
ND AND NW MN/...EXPECT THAT SCOURING OUT THE STRATUS SHOULD NOT BE
AN ISSUE. LIGHT WINDS AND RECENT RAINS WILL LIKELY RESULT IN SOME
RADIATIONAL FOG LATE TONIGHT WHERE CLEARING OCCURS FIRST...AND HAVE
EXPANDED FOG COVERAGE FOR LATE TONIGHT ACROSS THE AREA. AFTER A COOL
NIGHT...TEMPERATURES WILL BEGIN TO REBOUND THURSDAY AS UPPER RIDGING
AMPLIFIES AND WARM AIR ADVECTION SETS IN FOR THE AFTERNOON. WILL
ALSO HAVE PLENTY OF SUNSHINE /MAYBE A FEW CU/ AND A DRY AIRMASS IN
PLACE AS HIGH PRESSURE AXIS BUILDS ACROSS THE UPPER MIDWEST. H85
TEMPS INCREASE TO 5 TO 10 C FROM EAST TO WEST ACROSS THE FORECAST
AREA BY 00Z FRIDAY. DESPITE THIS WARM-UP...TEMPS STILL WILL AVERAGE
NEARLY 5 DEGREES BELOW NORMAL FOR HIGHS THURSDAY.


.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED MAY 22 2013

FRIDAY WILL SEE A HUGE CHANGEOVER ALOFT AS DEW POINTS AROUND 700MB
AT ABOUT -40 DEGREES C THURSDAY NIGHT WILL INCREASE TO ABOUT +5
DEGREES C BY FRIDAYS AFTERNOON. WITH 700MB TO 500MB LAPSE RATES ALSO
RUNNING ABOUT 7 DEGREES OR SO...A BIT TOUGH TO GAUGE AS
PRECIPITATION BREAKS OUT IN THE MODEL...THERE SHOULD BE A DECENT
CHANCE FOR AN ELEVATED BAND OF SHOWERS AND THUNDERSTORMS TO DEVELOP.
WILL CONTINUE WITH SOME MID RANGE POPS BUT MAYBE INCREASE JUST A
BIT. ELEVATED CAPE FROM AROUND 750MB TO 700MB RUNNING ABOUT 500 TO
700 J/KG WHICH SUPPORTS THUNDER CHANCES.

SATURDAY LOOKS LIKE A BIT OF A BREEZY DAY AS A WARM FRONT BECOMES
ESTABLISHED OVER THE SOUTHERN CWA INTO PARTS OF NORTHERN NEBRASKA. A
DECENT AMOUNT OF INSTABILITY LOW LEVEL SHEAR EXISTS BUT WINDS ALOFT
NOT VERY SUPPORTIVE OF ORGANIZED CONVECTION. NOT TO MENTION CAPPING
LOOKS PRETTY STRONG AND CONVECTION WILL LIKELY NEED TO DEVELOP
OUTSIDE OF THE AREA AND ADVECT IN. WILL DECREASE POPS A IT ON THE
NORTH THINKING CAPPING WILL HAVE EVERYTHING SHUT DOWN.

NO EASY ANSWERS FOR SUNDAY INTO WEDNESDAY AS A BOUNDARY LOOKS TO
LINGER AROUND MUCH OF THE TIME. RELATIVELY WEAK UPPER LEVEL FLOW
SHOULD PRECLUDE ANY MAJOR SEVERE WEATHER OUTBREAKS SUNDAY INTO
MONDAY BUT ENOUGH LOW LEVEL SHEAR AND INSTABILITY TO PROMOTE THE
POSSIBILITY FOR A FEW SEVERE STORMS. AS WE MOVE INTO TUESDAY AND
WEDNESDAY THE MODELS BEGIN TO SHIFT THE FASTER SOUTHWEST FLOW ALOFT
ONTO THE NORTHERN AND CENTRAL PLAINS WHICH IF WE STILL HAVE A
BOUNDARY AROUND THERE MAY BE A BETTER CHANCE FOR SEVERE
THUNDERSTORMS WITH DEEPER ENHANCED SHEAR. OTHERWISE...THE ECMWF
CONTINUES TO LOCK IN THE COOLER AIR SUNDAY AND MONDAY MORESO THAN
THE GFS AND GEM. TUESDAY AND WEDNESDAY WILL SEE A BETTER CHANCE FOR
WARMER CONDITIONS AND WITH THE LOW LEVEL RIDGE IN THE SOUTH
SHIFTING EAST THE GULF OPENS UP A LOT MORE AND DEEPER MOISTURE WILL
LIKELY EXIST. WILL UNFORTUNATELY HAVE POPS IN EVERY DAY BUT LEANING
TOWARDS BETTER CHANCES SOUTH SUNDAY AND MONDAY THEN ANYWHERE TUESDAY
AND WEDNESDAY...MAYBE A LITTLE BETTER IN THE EASTERN TWO THIRDS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1223 PM CDT WED MAY 22 2013

WIDESPREAD MVFR CIGS THIS EARLY AFTERNOON ALONG WITH SCT TO
NUMEROUS SHOWERS WILL CONTINUE THROUGH LATE AFTERNOON. SHOWERS
WILL DIMINISH FROM WEST TO EAST THIS EVENING TONIGHT ALTHOUGH LOW
LEVEL MOISTURE WILL REMAIN IN PLACE. IFR CIGS ARE EXPECTED
TO REDEVELOP WITH DECOUPLING LATER THIS EVENING AT SUX/FSD.
CLEARING IS EXPECTED TO PUSH IN FROM THE NORTH OVERNIGHT FIRST AT
HON AND THEN FSD...HOWEVER RESIDUAL MOISTURE WILL LIKELY RESULT IN
SOME AREAS OF RADIATIONAL BR/FG...ESPECIALLY IN HON VICINITY.
CLEARING OF LOW LEVEL STRATUS MAY ALSO OCCUR SLOWER THAN FORECAST
BY A FEW HOURS DUE TO VEERING WINDS IN A MOISTURE FAVORED ENE
DIRECTION. HOWEVER...BEFORE THE END OF THE TAF
PERIOD...HON/FSD/SUX SITES SHOULD ALL BE VFR.


&&

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

$$

SHORT TERM...
LONG TERM...08
AVIATION...

000
FXUS63 KFSD 221723
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1223 PM CDT WED MAY 22 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT WED MAY 22 2013

UPPER LEVEL LOW CONTINUES TO SPIN ACROSS THE AREA EARLY THIS
MORNING...FAIRLY CLOSE TO KYKN...BUT WITH SOME UNCERTAINTY GIVEN
WHAT IS HOPEFULLY A TEMPORARY LOSS OF THE GOES-EAST DATA DUE TO
LATE EVENING MALFUNCTION /ESTIMATED RETURN TOWARD 18Z TODAY/.
BULK OF PRECIPITATION CONTINUING TO OCCUR JUST ON BACK SIDE OF THE
MID LEVEL CENTER WHERE TENDENCY TO FOCUS A BIT OF LOWER TO MID LEVEL
FRONTOGENESIS AND ISENTROPIC LIFT IN THE 295-300K LAYER. RETURNS
HAVE REALLY VARIED OVERNIGHT...SOMETIMES NEARLY DISSIPATING...ONLY
TO REFORM AND BECOME QUITE WIDESPREAD JUST AN HOUR LATER. AT CURRENT
TIME...ABOUT THE BEST COVERAGE OF THE NIGHT SO FAR ALONG AND WEST OF
I29 AS PULSE IN THE ISENTROPIC LIFT WORKS WESTWARD NORTH OF THE
CYCLONE CENTER. TREATING LIKE A CLASSIC HIGH POP/LOW QPF EVENT AT
LEAST THROUGH THE EARLY MORNING HOURS...WITH SIGNS IN SEVERAL MODELS
OF A WEAKENING OF THIS TROWAL-LIKE FEATURE THROUGH THE MORNING...
BUT PERHAPS A RESURGENCE IN COVERAGE BY EARLY TO MID AFTERNOON NEAR
AND JUST E OF I29 IF SOLUTIONS TAKEN LITERALLY. GENERALLY...EXPECT A
DAY WITH OCCASIONAL SHOWERS...STARTING TO DWINDLE FROM THE WEST. NOT
EXPECTING TO SEE MUCH IN THE WAY OF CLEARING TODAY...PERHAPS A
PARTIAL BIT LEAKING INTO THE FAR NORTH/NORTHWEST. THUS WITH CLOUDS
AND EXPECTED PRECIPITATION...ANOTHER CHILLY DAY WITH FAIRLY LIMITED
RECOVERY FROM CURRENT READINGS...MEANING HIGHS 10 TO 15 DEGREES
BELOW NORMAL.

PRECIPITATION SHOULD WIND DOWN THROUGH THE EVENING HOURS TONIGHT
AS ISENTROPIC DOWN GLIDE INCREASES ACROSS THE AREA. ADDED MENTION
OF PATCHY FOG ACROSS CENTRAL SOUTH DAKOTA WHERE SKIES CLEAR AND
WINDS DECREASE. CONSIDERED EXPANDING FURTHER EAST...BUT FOG IS
CONDITIONAL ON TIMING OF CLEARING AND WIND POTENTIAL.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 340 AM CDT WED MAY 22 2013

RELATIVELY QUIET WEATHER IS EXPECTED ON THURSDAY WITH SURFACE
RIDGE PASSING THROUGH THE REGION TO THE NORTH. MODELS SUGGEST
RETURN FLOW SETS UP FAIRLY QUICKLY THURSDAY AFTERNOON INTO
THURSDAY NIGHT...THOUGH NO DIRECT TAP TO THE GULF IS PRESENT SO AM
NOT EXPECTING A SUBSTANTIAL INCREASE IN MOISTURE UNTIL FRIDAY NIGHT
INTO SATURDAY WHEN LOW LEVEL JET SETS UP ACROSS THE CENTRAL
PLAINS. MODELS SEEM TO SUGGEST A FAIRLY WEAK CAPPING
INVERSION...WITH THE POTENTIAL FOR STORMS TO DEVELOP AS A LEADING
SHORT WAVE BREAKS OFF UPPER LOW SPINNING ACROSS THE NW US. THE
ECMWF SUGGESTS THE UPPER WAVE MAY SHEAR OUT TO THE NORTH AND WEST
OF THE CWA AS IT TRIES TO WORK EAST INTO THE UPPER RIDGE ACROSS
THE CENTRAL PLAINS...WHILE THE GFS SUGGESTS A SERIES OF PHASED
WAVES TRAVELING ACROSS THE AREA. THE WAVES IN THE GFS SOLUTION
APPEAR TO BE CONVECTIVE DRIVEN...AND HAVE THEREFORE SIDED CLOSER
TO AN ECMWF SOLUTION. WITH THAT SAID...WAS NOT THAT EXCITED ABOUT
PRECIPITATION CHANCES AND LOWERED POPS SLIGHTLY...ESPECIALLY
DURING THE DAY ON FRIDAY. WITH BETTER MOISTURE RETURN FRIDAY
NIGHT...PRECIPITATION CHANCES APPEAR TO BE MORE SIGNIFICANT WITH
LITTLE CAPPING INVERSION FROM A LIFTING LAYER BETWEEN 700-800 MB.

OFF AND ON CHANCES OF PRECIPITATION CONTINUE TO PLAGUE THE
EXTENDED WITH DIRTY WEST TO SOUTHWEST FLOW ALOFT WITH WAVES
BREAKING OFF IN A PIECEMEAL FASHION AND MOVING THROUGH THE PLAINS.
WITH UPPER LOW REMAINING TO THE WEST...LOW LEVEL FLOW REMAINS
SOUTHEAST TO SOUTH THROUGH MUCH OF THE EXTENDED. THIS WILL RESULT
IN AN OVERALL GRADUAL WARMING TREND...ALONG WITH AN INCREASE IN
MOISTURE. WITH LITTLE AGREEMENT ON TIMING OF UPPER WAVES...LEFT
GUIDANCE POPS AS IS WITH CHANCES OF THUNDERSTORMS THROUGHOUT THE
EXTENDED.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1223 PM CDT WED MAY 22 2013

WIDESPREAD MVFR CIGS THIS EARLY AFTERNOON ALONG WITH SCT TO
NUMEROUS SHOWERS WILL CONTINUE THROUGH LATE AFTERNOON. SHOWERS
WILL DIMINISH FROM WEST TO EAST THIS EVENING TONIGHT ALTHOUGH LOW
LEVEL MOISTURE WILL REMAIN IN PLACE. IFR CIGS ARE EXPECTED
TO REDEVELOP WITH DECOUPLING LATER THIS EVENING AT SUX/FSD.
CLEARING IS EXPECTED TO PUSH IN FROM THE NORTH OVERNIGHT FIRST AT
HON AND THEN FSD...HOWEVER RESIDUAL MOISTURE WILL LIKELY RESULT IN
SOME AREAS OF RADIATIONAL BR/FG...ESPECIALLY IN HON VICINITY.
CLEARING OF LOW LEVEL STRATUS MAY ALSO OCCUR SLOWER THAN FORECAST
BY A FEW HOURS DUE TO VEERING WINDS IN A MOISTURE FAVORED ENE
DIRECTION. HOWEVER...BEFORE THE END OF THE TAF
PERIOD...HON/FSD/SUX SITES SHOULD ALL BE VFR.

&&

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

$$

SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...