Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 181809 AAC
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
109 PM CDT THU SEP 18 2014

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

MID LEVEL WARM FRONTAL SHOWERS/STORMS CONTINUE TO HOLD TOGETHER
THIS MORNING AS THEY MOVE INTO THE JAMES VALLEY. THUS...EXPANDED
SLIGHT CHANCE POPS EASTWARD INTO THE EARLY AFTERNOON. ALSO...LOW
CLOUDS AND FOG HUGGING THE EASTERN SIDE OF THE SISSETON HILLS THIS
MORNING WILL SLOWLY DISSIPATE INTO THE EARLY AFTERNOON.
OTHERWISE...EXPECT SOUTH WINDS TO INCREASE THROUGH THE DAY AS THE
SURFACE PRESSURE GRADIENT TIGHTENS UP AND THE MIXING LAYER DEEPENS
INTO THE AFTERNOON. EXPECT IT TO BECOME BREEZY/WINDY ACROSS MOST
OF THE REGION. UPDATED FORECAST.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
CURRENTLY WATCHING A STRATUS DECK ADVANCING WESTWARD ACROSS
CENTRAL MN AND SHOULD BE ENTERING BIG STONE AND TRAVERSE COUNTIES
BY SUNRISE. VSBYS HAVE GONE DOWN ACROSS CENTRAL MN AS WELL SO HAVE
ADDED FOG INTO THE FORECAST FOR THE FAR EASTERN CWA. WILL CONTINUE
TO MONITOR AND MAKE CHANGES AS NEEDED.

OTHERWISE...STILL EXPECTING BREEZY/GUSTY SOUTHERLY WINDS TO
DEVELOP TODAY AS PRESSURE GRADIENT TIGHTENS IN RESPONSE TO
APPROACHING SFC TROUGH. LOW LEVEL MOISTURE WILL BE ON THE INCREASE
AS WELL WITH DEWPOINTS AROUND 60 DEGREES. FRONTAL BOUNDARY WILL
MOVE INTO THE WESTERN DAKOTAS THIS EVENING...THEN EVENTUALLY
SPREAD EAST OVER THE CWA ON FRIDAY. BEST PRECIP CHANCES TONIGHT
LOOK TO REMAIN WEST AND NORTH OF THE CWA...BUT WILL MAINTAIN
SLIGHT CHANCE POPS FOR NORTHERN AREAS. ON FRIDAY CHANCES LOOK
RATHER SLIM AS WELL AS MUCH OF THE AREA WILL REMAIN CAPPED DUE TO
THE VERY WARM TEMPS ALOFT. WILL CARRY JUST SLIGHT CHANCES ON
FRIDAY. MODELS ALSO NOT SHOWING MUCH IN THE WAY OF QPF AS THE
FRONT MOVES THROUGH.

SLIGHTLY COOLER TEMPS WILL FOLLOW THE FRONT ON SATURDAY...BUT
SHOULD STILL BE MILD. NORTHWEST WINDS WILL BE A BIT BREEZY WITH
DRY CONDITIONS EXPECTED.


.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
AN UPPER LEVEL TROUGH WILL EXIT THE REGION TO THE EAST SATURDAY
NIGHT AS RIDGING BUILDS OVER THE ROCKIES. THE RIDGE WILL SLOWLY
PUSH ACROSS THE PLAINS STATES MONDAY AND TUESDAY. SURFACE HIGH
PRESSURE WILL BE DOMINANT DURING THE FIRST HALF OF THE TIME
PERIOD...KEEPING CONDITIONS DRY.

DIFFERENCES BEGIN TO SHOW UP IN THE MODELS TUESDAY AND WEDNESDAY
AS THE ECMWF DIGS AN UPPER LEVEL SHORTWAVE TROUGH OVER THE PLAINS
AND HAS A STRONGER MOISTURE RETURN THAN THE GFS. THIS RESULTS IN
THE ECMWF INDICATING PRECIPITATION OVER THE CWA TUESDAY AND
WEDNESDAY...WHILE THE GFS REMAINS DRY. HAVE GENERALLY FOLLOWED
CONSENSUS WITH THE SURROUNDING CWAS AND PUT SOME SMALL POPS IN
ACROSS THE SOUTHWESTERN CWA ON TUESDAY CLOSER TO AN APPROACHING
SURFACE TROUGH...BUT HAVE LEFT THE REST OF THE PERIOD DRY UNTIL
THE MODELS COME INTO BETTER AGREEMENT.

NEAR NORMAL TEMPERATURES WILL BE THE RULE THROUGH THE
PERIOD...WITH HIGHS IN THE 70S AND LOWS IN THE UPPER 40S TO MID
50S.


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

VFR CONDITIONS WILL PREVAIL TODAY INTO THIS EVENING ON SOUTHERLY
BREEZES OF 15 TO 25 KT WITH HIGHER GUSTS. RAPID REFRESH OUTPUT
ALONG WITH SREF PROBABILITIES OF LOW CLOUDS AND SOME OF THE
NUMERICAL GUIDANCE OUTPUT IS HIGHLIGHTING LATE TONIGHT THROUGH THE
FIRST HALF OF FRIDAY AS BEING IFR...FROM LOW STRATUS CLOUDS THAT
ARE EXPECTED TO DEVELOP AND SPREAD NORTHWARD ACROSS THE REGION. AS
SUCH...HAVE INTRODUCED IFR CIGS TO THE TAFS...UNTIL EXPECTED COLD
FROPA WORKING FROM WEST TO EAST SWITCHES WINDS AROUND TO THE
WEST-NORTHWEST AND STARTS DRYING OUT THE BOUNDARY LAYER AND
SCOURING OUT THE LOW CLOUDS. CONVECTIVE CHANCES OVERNIGHT AND INTO
THE FIRST HALF OF FRIDAY LOOK RATHER SMALL...SO TAFS REMAIN VOID
OF PRECIP MENTION AT THIS TIME.


&&

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

$$
UPDATE...MOHR
SHORT TERM...TMT
LONG TERM...PARKIN
AVIATION...DORN

WEATHER.GOV/ABERDEEN




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