Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 171609 AAB
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1109 AM CDT SUN AUG 17 2014

.UPDATE...
AREA OF SHOWERS AND THUNDERSTORMS MOVING INTO OUR WEST RIVER
COUNTIES LATE THIS MORNING. EXTENDED POPS LONGER INTO THE
AFTERNOON AND BROUGHT THEM FARTHER EAST TO ACCOUNT FOR THIS
ACTIVITY. LEFT HIGH TEMPS ALONE AT THIS TIME. CLOUD COVER MAY HOLD
READINGS BACK AND JUST SHY OF FCST...BUT WILL CONTINUE TO RIDE ON
THEM FOR NOW. NEXT ATTENTION WILL TURN TO A MUCH STRONGER UPPER
LVL WAVE CURRENTLY ACROSS NORTHERN WY. THIS WILL MOVE INTO THE
WESTERN DAKOTAS LATER THIS AFTN AND THRU OUR CWA
TONIGHT/OVERNIGHT. THIS WILL HELP TO GENERATE ADDITIONAL STORMS
DURING THAT TIME..SOME OF WHICH COULD BE STRONG TO SEVERE.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH TUESDAY
LINGERING SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE FAR
NORTHEAST CWA THIS MORNING...WHILE A STRATUS DECK ADVECTS SOUTH
OUT OF NORTH DAKOTA COVERING MUCH OF THE NORTHERN CWA. SOME FOG
HAS DEVELOPED...BUT NOTHING THAT APPEARS TO BE WIDESPREAD AT THIS
TIME. WILL KEEP AN EYE ON THE SITUATION IN CASE VISIBILITY TANKS
QUICKLY THIS MORNING AND AN ADVISORY IS NEEDED.

A CLUSTER OF THUNDERSTORMS HAS DEVELOPED OVER NORTHWEST SOUTH
DAKOTA THIS MORNING...BUT THE MAIN FORCING ASSOCIATED WITH A
RELATIVELY STRONG SHORTWAVE LAGS FURTHER BEHIND. MOST MODELS DO NOT
HAVE THE NW SD CONVECTION MAKING IT ALL THE WAY INTO OUR CWA...SO
REFLECTED THAT IN THE FORECAST...SOMETHING TO CONTINUE TO MONITOR
THROUGH THE MORNING HOURS HOWEVER. POPS THEN INCREASE FROM WEST TO
EAST ACROSS THE CWA LATER THIS AFTERNOON AND THROUGH THE NIGHT.
THERE IS ACTUALLY SOME SEMBLANCE OF A WEAK JET STREAK WITH THIS
SYSTEM...AND 500 MB HEIGHT FALLS ARE ON THE ORDER OF 5 TO 6
DECAMETERS. THE WESTERN CWA SHOULD SEE AMPLE SUNSHINE THIS
AFTERNOON...HOWEVER AREAS FURTHER EAST COULD BE UNDER STRATUS FOR
A GOOD MAJORITY OF THE DAY. MODELS ARE INDICATING AT LEAST 1500
J/KG OF CAPE TO WORK WITH ACROSS THE WEST. THERE WILL ALSO ACTUALLY
BE BULK SHEAR PRESENT TODAY AS WELL...AND COMBINED WITH STEEP
LAPSE RATES AND PLENTY OF MOISTURE....STORMS ARE LIKELY...AND SOME
MAY BE SEVERE. HAIL AND WIND WILL BE THE MAIN THREAT...AS WILL
HEAVY RAIN. SOME MODELS ARE MORE BULLISH THAN OTHERS...BUT AT LEAST A
WEAK LOW LEVEL JET IS ALSO EXPECTED TO DEVELOP...ALLOWING STORMS
TO PERSIST FURTHER EAST INTO THE OVERNIGHT HOURS.

LINGERING RAIN CHANCES PERSIST INTO MONDAY ACROSS THE NORTHEAST
CWA...BUT CONDITIONS SHOULD DRY OUT SOON THEREAFTER...AS A WEAK
RIDGE BUILDS IN FOR TUESDAY.

.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY

SEEING BETTER AGREEMENT WITHIN THE GFS/ECMWF DETERMINISTIC
RUNS...WITH THE ECMWF CONTINUING TO TREND TOWARDS THE GFS
DEPICTION OF UPPER FEATURES. SURFACE HIGH PRESSURE WILL LEAD TO
STABLE CONDITIONS ACROSS NORTHEASTERN COUNTIES...WITH A SHORTWAVE
EXPECTED TO PASS MAINLY SOUTH OF THE CWA EARLY WEDNESDAY.
WEDNESDAY AFTERNOON ANOTHER WAVE EMBEDDED WITHIN SOUTHWEST FLOW
ALOFT PUSHES INTO THE WESTERN DAKOTAS. A THIRD WAVE LIFTS OUT OF
NEBRASKA FOR FRIDAY.

TEMPERATURES ARE EXPECTED TO RUN AT OR A TAD ABOVE NORMAL THIS
PERIOD...THANKS TO DEVELOPMENT OF A LEE LOW. WEAK WARM ADVECTION
WILL START EARLY...AND MODEL DEWPOINTS SUGGEST A RANGE OF MID 60S
TO LOW 70S.

&&

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

IFR/MVFR CIGS/VISBY WILL BE AN ISSUE FOR KABR/KATY/KMBG THIS
MORNING. WE ALSO HAVE SEVERAL WEAK THUNDERSTORMS MOVING INTO
KMBG/KPIR TERMINALS THIS MORNING. GUIDANCE HAS MOST OF AREA SEEING
SOME IMPROVEMENT IN CIGS/VISBY THIS MORNING...WITH STORMS
WEAKENING AS WELL...SO MAINLY ADDRESSED ANY ISOLD TSTMS COVERAGE
WITH VCSH. BETTER CHANCE FOR COVERAGE OF THUNDER FOR KPIR/KMBG
COMES THIS AFTERNOON.

&&

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

$$
UPDATE...VIPOND
SHORT TERM...SERR
LONG TERM...CONNELLY
AVIATION...CONNELLY

WEATHER.GOV/ABERDEEN




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