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000
FXUS63 KABR 142342
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
642 PM CDT FRI JUN 14 2013

.UPDATE...
UPDATED 00Z AVIATION DISCUSSION BELOW.



&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
THE FORECAST CHALLENGE IS WHETHER OR NOT SFC-BASED CONVECTION WILL
DEVELOP ALONG/AHEAD OF A COLD FRONT PUSHING INTO THE FORECAST AREA
FROM THE WEST...AND IF ANY CONVECTION THAT CAN GET GOING WILL
BECOME SEVERE.

CURRENTLY...ISOLATED POCKETS OF ELEVATED CONVECTION HAVE BASICALLY
DISSIPATED OR MOVED OUT OF THE CWA. MOST OF THE FORECAST AREA IS
SEEING MORE SUN THAN CLOUDS...PROMOTING A POTENTIALLY DESTABILIZED
LATE AFTERNOON/EARLY EVENING BOUNDARY LAYER. TYPICAL...THE COLD
FRONTAL BOUNDARY /LOCATED OVER THE FAR WESTERN ZONES...AND PRETTY
MUCH STILL WEST OF THE MO RIVER/ IS PUSHING EAST SLOWER THAN
MODELS HAVE PREVIOUSLY BEEN PROGGING IT TO MOVE...LIKELY DUE TO
THE LACK OF A MEANINGFUL UPSTREAM MID-LEVEL SHORTWAVE TO PROVIDE
THE NEEDED SYNOPTIC SCALE KICK. OBJECTIVE ANALYSIS ALONG AND OUT
AHEAD OF THE COLD FRONT REVEALS MLCAPE VALUES ARE UP TO
1000-2000J/KG WHILE CINH VALUES ARE DOWN TO -75 TO -125 J/KG AND
0-6KM SHEAR IS HOLDING BETWEEN 35 AND 50 KNOTS.

TONIGHT...THE AFOREMENTIONED COLD FRONTAL BOUNDARY WILL EVENTUALLY
PICK UP SOME STEAM...HEADING EAST TOWARD MINNESOTA AS THE PARENT
UPPER LOW STRADDLING THE CANADIAN/U.S. BORDER OVER ALBERTA AND
MONTANA APPROACHES THE DAKOTAS/SOUTH CENTRAL CANADA. EXPECTING
SOME ISOLATED TO SCATTERED CONVECTION ALONG/AHEAD OF THIS COLD
FRONT ACROSS THE EASTERN CWA THROUGH AT LEAST LATE THIS EVENING.
STILL CANNOT RULE OUT A COUPLE OF STRONG TO SEVERE STORMS...MAINLY
ON OR EAST OF THE PRAIRIE COTEAU LATER THIS EVENING WORKING EAST
INTO MINNESOTA WITH LARGE HAIL AND DAMAGING WINDS THE PRIMARY
SEVERE WEATHER THREAT. /CAVEAT...IF THE UPPER FORCING CATCHES UP
TO THE SURFACE COLD FRONT SOONER THAN LATER WHEN THE COLD FRONT IS
STILL WORKING THROUGH CENTRAL/NORTH CENTRAL SOUTH
DAKOTA...CONVECTIVE ACTIVITY COULD END UP FIRING A GOOD BIT
FURTHER WEST THAN CURRENTLY FORECAST./ CONTINUING WITH SEVERE
THUNDER MENTION IN THE WX GRIDS OVER THE EASTERN FORECAST ZONES
THROUGH 06Z. OVERNIGHT LOW TEMPERATURES SHOULD COOL INTO THE 40S
AND 50S AS MARKEDLY DRIER BOUNDARY LAYER AIR ADVECTS INTO THE CWA
FROM WEST TO EAST.

SATURDAY/SATURDAY NIGHT...DRY STABLE HIGH PRESSURE SETTLES IN FOR
A PLEASANT DAY/EVENING BEFORE SOME RETURN FLOW BEGINS TO SET UP
ACROSS THE WESTERN HALF OF SOUTH DAKOTA LATE SATURDAY NIGHT OUT
AHEAD OF THE NEXT MID-LEVEL SHORTWAVE IMPULSE OF LOW PRESSURE. LOW
LEVEL THERMAL PROGS SUGGEST NEAR CLIMO HIGHS/LOWS ARE PROBABLE
SATURDAY AND SATURDAY NIGHT.



.LONG TERM...SUNDAY THROUGH FRIDAY

DECENT AGREEMENT EXISTS BETWEEN LONG TERM DETERMINISTIC GFS AND
ECMWF WITH THE MAJOR FEATURES WITHIN THE EXTENDED PERIOD.
INITIALLY...HAVE A FAVORABLE SCENARIO FOR SEVERE WEATHER WITH A
NORTHWEST FLOW SHORTWAVE ACROSS EASTERN NORTH DAKOTA/NORTHERN
MINNESOTA. THIS...COMBINED WITH A FAVORABLE 80KT JET POSITION WILL
RESULT IN STEEP MID LEVEL LAPSE RATES. THIS SCENARIO ALSO FEATURES
LIMITED RETURN FLOW AND LACK OF MOISTURE...SO SHOULD BE DEALING
WITH AN ENVIRONMENT FAVORABLE FOR DIURNALLY DRIVEN...ELEVATED
SURFACE BASED CONVECTION AND THUS MAINLY A WIND AND HAIL
THREAT.

FOR THE START OF NEXT WEEK...UPPER RIDGING WILL DOMINATE THE
WEATHER PATTERN. RETURN FLOW DEVELOPS BY MID WEEK...SO WILL START
TO SEE INCREASING CHANCES FOR STORMS. THOUGH MODELS DO BEGIN TO
DIVERGE IN THEIR HANDLING OF THE DISPLACEMENT OF THE UPPER RIDGE
EAST AS A WESTERN CONUS TROF MOVES ACROSS THE NORTHERN
ROCKIES...WITH THE GFS BEING A TAD MORE PROGRESSIVE...THE
COMBINATION OF SOUTHWEST FLOW ALOFT...AND PERSISTENT SOUTHERLY LOW
LEVEL FLOW...SUGGESTS AN ACTIVE PATTERN FOR THE CONCLUSION OF THE
FORECAST PERIOD.



&&

.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

INVERTED TROF OF LOW PRESSURE CURRENTLY LOCATED JUST TO THE WEST
OF THE KABRKHON TERMINAL LOCATIONS. AHEAD OF THIS TROF MOIST AND
UNSTABLE AIR IS PRESENT. AS THIS TROF MOVES EAST AND ENCOUNTERS
THIS UNSTABLE AIR...ISOLD TSRA POSSIBLE AT THE KATY TERMINAL
THROUGH 02Z. AFTERWARDS LOOK FOR VFR SKY/VSBY CONDS TO TAKE PLACE.
FURTHER WEST...HIGH PRESSURE BUILDING IN FROM THE WEST WILL KEEP
VFR SKY/VSBYS IN PLACE FOR THE KPIR/KMBG AND KABR TERMINAL THROUGH
THE VALID TAF PERIOD.


&&

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

$$
UPDATE...HINTZ
SHORT TERM...DORN
LONG TERM...CONNELLY
AVIATION...HINTZ

WEATHER.GOV/ABERDEEN