Area Forecast Discussion
Issued by NWS Aberdeen, SD

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000
FXUS63 KABR 061951
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
251 PM CDT WED MAY 6 2015

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 244 PM CDT WED MAY 6 2015

FORECAST CHALLENGES CONTINUE TO REVOLVE AROUND PRECIP TIMING/AMOUNTS
OVER THE NEXT 36 HOURS.

CURRENTLY...WITH OVERCAST SKIES AND WINDS FROM THE SOUTHEAST AT 10
TO 20 MPH...TEMPERATURES ARE HOLDING IN THE 60S WHILE A COMPLEX
PATTERN OF SHOWERS AND THUNDERSTORMS CONTINUES TO DEVELOP AND LIFT
NORTH-NORTHWEST. FOR THE FIRST TIME THIS YEAR...SURFACE DEWPOINTS
ARE IN THE 60S OVER THIS CWA. THE PRECIP OVER THE EASTERN HALF OF
THE CWA SEEMS TO BE A COUPLE OF WAA-FORCED BANDS OF RAIN
SHOWERS...WHILE CHARACTER OF PRECIPITATION DEVELOPING ACROSS THE
WESTERN HALF OF THE CWA APPEARS MORE CONVECTIVE IN NATURE...AS
NUMEROUS DISCRETE SHOWERS AND WEAK THUNDERSTORMS. MIXED-LAYER CAPE
REMAINS RATHER LOW GIVEN ALL THE CLOUD COVER AROUND. MOST UNSTABLE
CAPES HAVE INCREASED TO BETWEEN 500-1000J/KG.

THE MAIN UPPER CIRCULATION WITHIN THE LONGWAVE TROF IS LOCATED OVER
WESTERN NEBRASKA...AND IS FORECAST TO OPEN AND LIFT UP TOWARD
NORTHERN MINNESOTA TONIGHT AND THURSDAY. IT`S PROBABLE THAT THE
WESTERN OR NORTHWESTERN ZONES IN THIS CWA WILL CONTINUE TO BE
INFLUENCED OVER THE NEXT 24 HOURS BY DEFORMATION-ZONE FORCED LIGHT
BANDED RAIN SHOWER PRECIPITATION /PERHAPS A FEW RUMBLES OF THUNDER
THROUGH LATE THIS EVENING/. HOWEVER...SHORT RANGE HI-RES AND RAPID
REFRESH MODEL OUTPUT IS SUGGESTING IT`S EVEN MORE PROBABLE THAT A
CLUSTER OR COMPLEX OF THUNDERSTORMS...POSSIBLY THE CONVECTION
GETTING GOING NOW IN NORTH CENTRAL KANSAS/SOUTH CENTRAL
NEBRASKA...WILL CONTINUE TO DEVELOP OR EXPAND NORTH-NORTHEAST LATER
THIS EVENING AND SPREAD SOME HEAVIER RAINFALL AMOUNTS UP THROUGH THE
EASTERN FORECAST ZONES...MAINLY ALONG AND EAST OF THE I-29 CORRIDOR.
WHILE THERE MAY CONTINUE TO BE SOME LOW-END CAPE AROUND
OVERNIGHT...DEEP LAYER SHEAR IS CURRENTLY AND WILL LIKELY REMAIN
LESS THAN 30 KNOTS AS ALL THIS CONVECTIVE POTENTIAL LIFTS
NORTH-NORTHEAST OVERNIGHT TONIGHT.

THERE MAY BE SOME REMNANT TROWAL-FORCED OR COLD AIR INSTABILITY-
INDUCED SHOWERS/THUNDERSTORMS AROUND ON THURSDAY. OTHERWISE...MUCH
OF THE REST OF THE SHORT TERM FORECAST PERIOD THROUGH FRIDAY NIGHT
SHOULD BE DRY WHILE COOLER...MORE STABLE SURFACE HIGH PRESSURE
BUILDS SOUTH OUT OF CANADA...DRYING OUT THE LOW LEVEL MOISTURE...AND
TURNING TEMPERATURES A TOUCH COOLER THAN THE PAST FEW DAYS.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 244 PM CDT WED MAY 6 2015

THERE IS A REASONABLE AGREEMENT BETWEEN THE GFS/ECMWF WITH REGARDS
TO PCPN CHANCES THROUGH THE PERIOD. AN AREA OF LOW PRESSURE OVER THE
FRONT RANGE OF THE ROCKIES IN COLORADO ON SATURDAY WILL TRACK
NORTHEASTWARD THROUGH MONDAY. THIS SYSTEM WILL BRING A DECENT AMOUNT
OF RAINFALL TO THE CWA ON SUNDAY AND SUNDAY NIGHT. TOTAL RAINFALL
AMOUNTS AROUND A THIRD OF AN INCH IS HIGHER LIKELY WITH THIS EVENT.
THERE IS A POTENTIAL FOR HIGHER RAINFALL AMOUNTS. TEMPERATURES WILL
BE VERY COOL WITH HIGHS ONLY WARMING INTO THE 50S ON SATURDAY
THROUGH MONDAY. SUNDAY WILL LIKELY BE THE COLDEST DAY WITH HIGHS
ONLY IN THE UPPER 40S FOR THE WESTERN CWA. WHILE THERMAL PROFILES
SUPPORT AN ALL RAIN EVENT...WOULD NOT BE TOO SURPRISED IF THE FAR
WESTERN PORTION OF THE CWA SEES LIGHT SNOW BY MONDAY MORNING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1241 PM CDT WED MAY 6 2015

WHILE MVFR CONDITIONS ARE EXPECTED THROUGH TONIGHT...WIDESPREAD
SHOWERS COULD REDUCE FLYING CONDITIONS TO IFR LEVELS AT TIMES. IFR
CONDITIONS ARE HIGHLY LIKELY FOR ALL TERMINALS BETWEEN 10Z-15Z
WITH LOW CLOUDS AND FOG. WINDS SHOULD SHIFT TO THE NORTHWEST
AROUND 15Z WHICH WILL SLOWLY IMPROVE FLYING CONDITIONS.

&&

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

$$

SHORT TERM...DORN
LONG TERM...SD
AVIATION...SD


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