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000
FXUS63 KABR 250859
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
359 AM CDT SAT MAY 25 2013

.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.

MONDAY...THE SURFACE LOW BEGINS TO MOVE EASTWARD INTO THE PLAINS
STATES. AS THIS HAPPENS THE SURFACE WARM FRONT MOVES NORTHWARD AND
APPEARS AS THOUGH IT WILL BE DRAPED FROM WEST TO EAST ACROSS OUR
CWA MONDAY AFTERNOON. AGAIN...PLENTY OF MOISTURE AND INSTABILITY
/ML CAPE VALUES RISING TO 3000 J/KG/ ACROSS THE WHOLE CWA...NOT TO
MENTION STEEP LAPSE RATES AND INCREASING 0-6 KM SHEAR THROUGH THE
DAY. PERHAPS A LITTLE STRONGER OF A CAP ON MONDAY...BUT UNLIKE THE
PREVIOUS DAYS...MODELS ARE SHOWING A DISTINCT UPPER LEVEL WAVE OF
ENERGY MOVING ACROSS THE REGION RIGHT AT PEAK HEATING. THE SEVERE
THUNDERSTORM THREAT FOR MONDAY BECOMES INCREASINGLY EVIDENT WITH
EVERY MODEL RUN.

.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...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

VFR CONDITIONS WILL PREVAIL DURING THE OVERNIGHT HOURS AS AN AREA
OF CIGS AROUND 5K FEET PUSHES ACROSS THE EASTERN CWA...AND HIGH
CLOUDS AOA 15K FEET STREAM UP FROM THE SOUTH. AFTER A MOSTLY DRY
DAY ON SATURDAY...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP ACROSS THE WESTERN PART OF THE STATE DURING THE LATE
AFTERNOON HOURS...THEN SPREAD EASTWARD DURING THE EVENING. PERIODS
OF MVFR CIGS AND VSBYS ARE POSSIBLE WITH THE THUNDERSTORMS. GOT
THE BALL ROLLING WITH SOME BROAD-BRUSHED VICINITY THUNDER MENTION
AT THE END OF THE TAF VALID PERIOD. EXPECT START TIME AND DURATION
TO CHANGE OVER THE NEXT FEW TAF ISSUANCE`S ONCE A HIGHER CONFIDENCE
TS FORECAST CAN BE IMPLEMENTED.

&&

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

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

WEATHER.GOV/ABERDEEN