000
FXUS63 KABR 181750 AAC
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1250 PM CDT TUE JUN 18 2013

.UPDATE...

UPDATED AVIATION DISCUSSION BELOW FOR 18Z TAFS.

HIGH PRESSURE OVER THE REGION TODAY IS KEEPING THE WEATHER FAIRLY
QUIET. NO CHANGES NEEDED TO THE DAYTIME FORECAST PERIOD. MADE A FEW
ADJUSTMENTS TO EVENING AND OVERNIGHT POPS. INSTABILITY IS STILL
EXPECTED TO INCREASE ACROSS WESTERN SD THIS EVENING...BUT EASTWARD
PROPAGATION SHOULD BE LIMITED TO WEST RIVER TONIGHT. HI- RES
MODELS REFLECT THIS THINKING.


&&

.PREVIOUS DISCUSSION...

.SHORT TERM...TODAY THROUGH THURSDAY
THE UPPER LEVEL SHORTWAVE ENERGY RESPONSIBLE FOR ISOLATED
THUNDERSTORMS OVERNIGHT HAS MOVED SOUTHEAST OF THE CWA. AN UPPER
RIDGE WILL BUILD OVER THE REGION TODAY...WITH SURFACE HIGH
PRESSURE SLOWLY DRIFTING EASTWARD THIS AFTERNOON. THIS WILL ALLOW
FOR RETURN FLOW WINDS ACROSS THE WESTERN CWA...AS WELL AS MLCAPE
VALUES RISING INTO THE 1000-1500 J/KG RANGE. NO SIGNIFICANT
SYNOPTIC FORCING TO SPEAK OF...BUT IF ANYTHING GETS GOING IN THE
BLACK HILL REGION...IT MAY PROPAGATE EASTWARD INTO OUR CWA. MODELS
ARE SHOWING AROUND 30 KTS OF 0-6 KM SHEAR...SO IF STORMS CAN MAKE
IT THIS FAR EAST...THERE CERTAINLY IS THE POSSIBILITY OF ISOLATED
STRONG OR SEVERE STORMS ACROSS THE FAR SOUTHWEST CWA.

THE LLJ INCREASES TUESDAY NIGHT INTO WEDNESDAY MORNING...WITH
ABOUT 30 KTS NOSING INTO OUR SOUTHERN CWA. THIS MAY INDUCE
ELEVATED CONVECTION OVERNIGHT AND INTO WEDNESDAY MORNING. MODELS
ARE SHOWING SHORTWAVE ENERGY MOVING ACROSS THE REGION ON WEDNESDAY
AFTERNOON...ALTHOUGH IT LOOKS LIKE THE TIMING WILL BE A LITTLE TOO
EARLY AND HEATING WILL BE LIMITED WEDNESDAY AFTERNOON.

THE SURFACE LOW INTENSIFIES AND MOVES EASTWARD...AND A 30 TO 40
KT LLJ JET AGAIN SETS UP WEDNESDAY NIGHT INTO THURSDAY
MORNING...SO ANOTHER ROUND OF ELEVATED OVERNIGHT CONVECTION IS
ANTICIPATED. BY THURSDAY AFTERNOON THE SURFACE INVERTED TROUGH
WILL BE SITUATED ACROSS CENTRAL SOUTH DAKOTA. UPPER LEVEL HEIGHTS
CONTINUE TO RISE HOWEVER...AND WITH THE CHANCE OF DEBRIS CLOUDS
LEFT OVER FROM OVERNIGHT/EARLY MORNING CONVECTION...IT SEEMS AS
THOUGH THERE WILL BE LIMITED AFTERNOON HEATING AND AN INCREASING
CAP. LEFT THE CHANCE POPS IN THE FORECAST FOR NOW...BUT WILL HAVE
TO CONTINUE TO MONITOR THE MODEL TRENDS AND TIMING OF THIS SYSTEM
ON THURSDAY.


.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
AN UPPER LEVEL RIDGE OVER THE EASTERN PLAINS THURSDAY NIGHT WILL
TRACK EAST OF THE AREA ON FRIDAY AS LOW PRESSURE SPINS OVER THE
PACIFIC NORTHWEST. THE LOW WILL TRACK NORTHWARD TO SOUTH CENTRAL
CANADA BY SUNDAY MORNING...THEN SOUTHWESTERLY FLOW WILL REMAIN IN
PLACE...WITH A SERIES OF SHORTWAVES TRACKING ACROSS THE NORTHERN
PLAINS THROUGHOUT THE PERIOD.

SURFACE LOW PRESSURE WILL BE OVER THE WESTERN HIGH PLAINS THURSDAY
EVENING...THEN SLOWLY WORKS ITS WAY EASTWARD DURING THE
NIGHT...BECOMING NEARLY STATIONARY OVER SOUTH DAKOTA/NEBRASKA
THROUGH SUNDAY. WILL SEE A DECENT MOISTURE SURGE ON THE EAST SIDE
OF THIS SYSTEM. STRONG INSTABILITY DEVELOPS ACROSS THE ENTIRE CWA
FRIDAY AFTERNOON AND EVENING...AND AGAIN SATURDAY AFTERNOON AND
EVENING ACROSS THE EAST...WITH CAPE VALUES IN EXCESS OF 5000 J/KG
FRIDAY...AND BETWEEN 3500-4500 J/KG ON SATURDAY. BULK SHEAR
VALUES WILL BE THE BEST ACROSS THE NORTHERN CWA. HOWEVER...CURRENT
H7 TEMPERATURES ARE FORECAST TO BE IN THE +12 TO +16 DEGREE RANGE
ON FRIDAY...WHICH WILL LIKELY BE TOO MUCH OF A CAP TO OVERCOME.
THE CAP BEGINS TO WEAKEN ON SATURDAY...WHICH MAY MAKE THAT A
BETTER DAY TO SEE SOME STRONG TO SEVERE STORMS...MAINLY ACROSS THE
FAR EASTERN CWA. THE UNSETTLED PATTERN WILL CONTINUE SUNDAY AND
MONDAY AS ANOTHER SURFACE LOW APPROACHES FROM THE WEST,

TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE PERIOD...WITH
DAYTIME HIGHS IN THE 80S AND OVERNIGHT LOWS IN THE 60S.


&&

.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD. THERE IS A
CHANCE FOR TSRA TO MAKE IT TO THE KPIR TAF SITE LATE TONIGHT AS
LATE AFTERNOON CONVECTION PUSHES EAST INTO CENTRAL SD. WHETHER OR
NOT IT MAKES IT TO KPIR IS STILL UNCERTAIN AND AREAL COVERAGE WILL
LIKELY BE SPARSE LATE TONIGHT SO HAVE OPTED TO KEEP OUT OF TAFS AT
THIS TIME. TSRA ALSO POSSIBLE BY LATE MORNING OR EARLY AFTERNOON
WEDNESDAY NEAR KATY. BUT AGAIN...CONFIDENCE IN THIS AFFECTING THE
TAF SITE IS FAIRLY LOW AT THIS POINT BUT FUTURE TAFS MAY INCLUDE
MENTION OF TSRA.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
UPDATE...WISE/TMT
SHORT TERM...SERR
LONG TERM...PARKIN
AVIATION...TMT

WEATHER.GOV/ABERDEEN