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000
FXUS63 KABR 251142 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
642 AM CDT SAT MAY 25 2013

.UPDATE...
SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH MONDAY
CURRENT WATER VAPOR IMAGERY IS SHOWING THAT THE UPPER FLOW HAS
TRANSITIONED TO MORE OF A SOUTHWESTERLY DIRECTION OVER SOUTH
DAKOTA. SEVERAL WAVES OF ENERGY ARE EVIDENT ACROSS THE CENTRAL AND
SOUTHERN PLAINS...AND A NOTABLE MCS IS MOVING ACROSS NEBRASKA
THIS MORNING. HIGH CLOUDS ASSOCIATED WITH THIS SYSTEM HAVE SPREAD
ACROSS OUR CWA.

TODAY...SOUTHEASTERLY SURFACE FLOW WILL CONTINUE TO ADVECT WARM
MOIST AIR INTO THE REGION. ML CAPE VALUES WILL RISE TO THE
1000-2000 J/KG RANGE ACROSS THE WESTERN HALF OF THE CWA....ALONG
WITH STEEP MID LEVEL LAPSE RATES AND 0-6 KM SHEAR IN THE 30 TO 40
KT RANGE. WHILE SEVERAL WEAK EMBEDDED WAVES OF ENERGY MAY BE
MOVING THROUGH THE UPPER FLOW...IT IS HARD TO IDENTIFY THE
TIMING/STRENGTH OF ANY OF THOSE WAVES AT THIS TIME.
CURRENTLY...THE MODELS ARE SUGGESTING THAT AFTERNOON STORMS WILL
INITIATE ACROSS WESTERN SOUTH DAKOTA...AND WORK
EASTWARD...TRACKING AS AN MCS ACROSS THE CWA THROUGH THE EVENING
AND OVERNIGHT HOURS. LARGE HAIL AND STRONG WINDS MAY BE A THREAT
AS THOSE STORMS MOVE INTO THE WESTERN CWA LATE THIS AFTERNOON.
THERE WILL BE A WEAK LLJ JET THAT DEVELOPS OVERNIGHT...HOWEVER
THE SEVERE THREAT WANES AS THE SYSTEM MOVES EASTWARD OVERNIGHT.

SAME BASIC SET UP AS WE MOVE INTO SUNDAY...VERY UNSTABLE AIRMASS
WITH PLENTY OF MOISTURE AND BULK SHEAR. OF A NOTABLE DIFFERENCE
HOWEVER IS THE LOW LEVEL SHEAR PRESENT...WITH 20 KTS OF 0-1 KM
SHEAR CONSISTENTLY SHOWING UP ON MODEL RUNS. HOWEVER THERE IS
STILL A LOT OF UNCERTAINTY IN THIS FORECAST...MAINLY WITH
PICKING OUT ANY UPPER LEVEL LIFT AND WHERE/WHEN STORM INITIATION
WILL TAKE PLACE. HOPEFULLY AFTER A COUPLE MORE MODEL
RUNS...INCLUDING SOME DETAILED HI RES MODEL DATA...THE FORECAST
WILL GAIN MORE CONFIDENCE.


.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
NO SUBSTANTIAL CHANGES COMPARED TO 24 HOURS AGO. STILL PLENTY OF
PERIODS OF PRECIPITATION POTENTIAL. SOUTHWESTERLY FLOW WITH
EMBEDDED SHORTWAVES IS FORECAST UNTIL THE THURSDAY/FRIDAY
TIMEFRAME WHEN AN UPPER LOW IS FORECAST TO CLOSE OFF SOMEWHERE
BETWEEN NORTH DAKOTA AND KANSAS AND SPIN SLOWLY THROUGH THE
REGION. POSITIONING AND TIMING OF THIS UPPER LOW MAY OR MAY NOT
PERMIT POPS TO PERSIST INTO NEXT WEEKEND...STAY TUNED. TEMP-
WISE...NO NOTEWORTHY CHANGES MADE TO GOING LONG TERM FORECAST.
STILL LOOKS LIKE 925HPA AND 850HPA THERMAL PROGS SUPPORT THE
POTENTIAL FOR HIGH TEMPERATURES INTO THE 70S THROUGH MUCH OF THE
PERIOD...BEFORE COOLER/MORE CLOUDY AND POTENTIALLY RAINY
CONDITIONS TAKE HOLD OF THE REGION HEADING INTO THE WEEKEND.


&&

.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

VFR CONDITIONS WILL PREVAIL FOR MUCH OF THE TAF VALID PERIOD.
LATER TONIGHT...LOW LEVEL MOISTURE ADVECTION UNDER A BOUNDARY
LAYER INVERSION WILL HELP TO PROMOTE AN AREA OF MVFR STRATUS
ACROSS THE CWA...BASICALLY AFFECTING ALL FOUR TERMINALS. A MOSTLY
DRY DAY IS EXPECTED TODAY ACROSS THE REGION...ESPECIALLY PRIOR TO
21Z. THEN...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP ACROSS THE NORTHERN HIGH PLAINS OF THE WESTERN
DAKOTAS AS WELL AS EASTERN MONTANA AND NERN WYOMING...ESPECIALLY
BETWEEN 21Z AND 03Z. CONVECTION...SOME OF WHICH IS FORECAST TO
BECOME STRONG TO SEVERE...IS EXPECTED TO THEN SPREAD EASTWARD
DURING THE EVENING /POTENTIALLY IMPACTING THE KMBG AND KPIR
TERMINALS/. THE KABR AND KATY TERMINALS COULD BE AFFECTED BY
THUNDERSTORM ACTIVITY MUCH LATER IN THE NIGHT...BASICALLY AT OR
AFTER 06Z TONIGHT. PERIODS OF MVFR/IFR CIGS AND VSBYS ARE
POSSIBLE WITH THE THUNDERSTORMS. OTHERWISE...EXPECT BKN-OVC MVFR
STRATUS TO DEVELOP TONIGHT AND PERSIST INTO SUNDAY MORNING.
CONTINUED TO CARRY SOME BROAD-BRUSHED VICINITY THUNDER MENTION AT
EACH TERMINAL FOR A FEW HOURS...MAINLY DURING THE SECOND HALF OF
THE TAF VALID PERIOD. EXPECT START TIME AND DURATION TO CHANGE
OVER THE NEXT FEW TAF ISSUANCE`S ONCE A HIGHER CONFIDENCE
THUNDERSTORM FORECAST CAN BE IMPLEMENTED.


&&

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

$$
UPDATE...DORN
SHORT TERM...SERR
LONG TERM...DORN
AVIATION...DORN

WEATHER.GOV/ABERDEEN