000
FXUS63 KABR 251750 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1250 PM CDT SAT MAY 25 2013

.UPDATE...
18Z AVIATION DISCUSSION UPDATED BELOW.

THE CURRENT FORECAST LOOKS PRETTY GOOD OVERALL. THE ONLY
SIGNIFICANT CHANGE WAS TO DELAY THE ONSET OF THUNDERSTORMS IN THE
WESTERN CWA UNTIL CLOSER TO 21Z OR AFTER. COMPLETELY REMOVED POPS
IN THE EASTERN CWA UNTIL AFTER 3Z AND EVEN THAT MIGHT BE TOO SOON.
A NOTICEABLE JET STREAK IS MOVING INTO WESTERN SOUTH DAKOTA WITH
CU ALREADY BEGINNING TO DEVELOP IN NW SOUTH DAKOTA. WHEN STORMS
DEVELOP...THEY WILL LIKELY TRACK NORTHEASTWARD AND SHOULD NOT
AFFECT THIS CWA. WOULD EXPECT MOISTURE POOLING OVER NEBRASKA/SW
SOUTH DAKOTA THIS AFTERNOON...ALONG WITH THE UPPER JET TO BE THE
FOCUS FOR STRONG TO SEVERE STORM DEVELOPMENT OVER THE BLACK HILLS.
IF THESE STORMS DO DEVELOP...THEY WILL LIKELY TRACK ESE ACROSS THE
SOUTHWEST PORTION OF THE CWA...AFFECTING KPIR BETWEEN 0-6Z. WILL
FINE TUNE ONCE MORE WHEN 12Z DATA COMES IN.


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

PERSISTENT LOW LEVEL EAST TO SOUTHEAST WINDS WILL BRING IN HIGH
LOW LEVEL RH THROUGH THE DAY AND NIGHT ACROSS THE CWA.
THUS...EXPECT SOME VFR MIXING LAYER CLOUDS TODAY FOR ALL
TERMINALS. EXPECT THESE CEILINGS TO LOWER TO MVFR/IFR THROUGH THE
EVENING AND OVERNIGHT ALONG WITH SOME MVFR FOG FORMING. EXPECT THE
LOW CEILINGS TO LAST THROUGH SUNDAY MORNING. OTHERWISE...EXPECT
SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP THIS EVENING AND
OVERNIGHT MOVING FROM WEST TO EAST. SOME OF THESE MAY AFFECT THE
TERMINALS AT OR IN THE VICINITY. WILL HOLD OFF AND AMEND IF STORMS
LOOK THREATENING TO ANY TERMINAL.



&&

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

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

WEATHER.GOV/ABERDEEN