Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 202313
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
513 PM MDT SUN APR 20 2014

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 238 PM MDT SUN APR 20 2014

UPPER LEVEL ANALYSIS HAS MAINLY ZONAL FLOW ACROSS THE NORTHERN
HIGH PLAINS...WITH SHORTWAVE TROF MOVING QUICKLY EAST ACROSS
SOUTHERN CANADA. SKIES ARE MAINLY SUNNY ACROSS THE AREA WITH
A BAND OF THIN MID CLOUDS ACROSS WESTERN AREAS. AT THE
SURFACE...COLD FRONT IS CROSSING THE FORECAST AREA AT THE MOMENT.
TEMPS ARE IN THE 60S BEHIND THE FRONT...AND IN THE 70S AHEAD.
WINDS ARE BREEZY OUT OF THE NORTH BEHIND THE FRONT...AND OUT OF
THE SOUTH TO SOUTHEAST ACROSS SOUTH CENTRAL SOUTH DAKOTA.

WARM AND MAINLY DRY WX WILL CONTINUE INTO EARLY THIS WEEK AS NEAR
ZONAL FLOW ALOFT PERSISTS. FOR LATE THIS AFTERNOON...ISOLATED
SHOWERS AND STORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT IN
SOUTH CENTRAL SOUTH DAKOTA...AND PERSIST INTO EARLY EVENING. A FEW
STRONGER STORMS WILL BE POSSIBLE. MAINLY CLEAR SKIES ARE EXPECTED
ACROSS THE REMAINDER OF THE AREA. LOWS WILL FALL INTO THE 30S TO
MID 40S.

MONDAY WILL BE MOSTLY SUNNY WITH MILD TEMPERATURES...AND
RELATIVELY LIGHT WINDS. HIGHS WILL BE IN THE 60S AND LOWER 70S.
LOWS MONDAY NIGHT WILL GENERALLY BE IN THE MID 30S TO MID
40S...WITH SOUTH TO SOUTHEAST WINDS DEVELOPING OVER THE ENTIRE
AREA.


&&

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 238 PM MDT SUN APR 20 2014

MODELS REMAIN IN REASONABLE AGREEMENT THROUGH THE MEDIUM RANGE.
AN UPPER LEVEL TROUGH WILL ENTER THE PACIFIC NORTHWEST EARLY
TUESDAY AND WILL AFFECT THE WEATHER OVER THE THE NORTHERN PLAINS
THROUGH THURSDAY.

ON TUESDAY...LOW PRESSURE WILL DEVELOP OVER WRN MT LEADING TO WINDY
SOUTHERLY RETURN FLOW OVER THE FORECAST AREA. THE LOW WILL DEEPEN AS
IT MOVES INTO SOUTHEAST MT BY TUES EVE WITH A SFC TROUGH MOVING INTO
ERN WY/FAR WRN SD. SHEAR PROFILES INDICATE THAT A FEW STRONG TSRA
MAY DEVELOP ALONG/AHEAD OF THE SFC TROUGH...BUT MOISTURE
AVAILABILITY REMAINS IN QUESTION GIVEN AMOUNT OF MIXING AS
TEMPERATURES CLIMB WELL INTO THE 70S.

ON WEDNESDAY...THE INITIAL SFC TROUGH WILL MOVE EAST OF THE FORECAST
AREA AS THE UPPER LOW WRAPS UP OVER NRN MT. THIS WILL PUSH DRIER AIR
INTO CWA EARLY...BUT MOISTURE WILL RETURN LATER  WED NIGHT AS WRAP
AROUND SHIFTS SOUTH FROM MT/ND. TEMPERATURES WILL BE QUITE WARM
GIVEN FORECAST SOUNDINGS WITH WEAK INSTABILITY SUPPORTIVE OF DIURNAL
-TSRA. AS PRECIPITATION TRENDS TO -SHRA WEDNESDAY NIGHT...A FEW
-SHSN POSSIBLE IN THE HIGHER ELEVATIONS GIVEN WET BULB PROFILES.

THURSDAY...UPPER/SURFACE LOW SHIFTS EAST INTO THE UPPER MIDWEST. A
TROUGH/FRONT EXTENDING WESTWARD FROM THE LOW...COMBINED WITH
CYCLONIC UPPER FLOW MAY PROVIDE ENOUGH INSTABILITY FOR A FEW SHOWERS
OVER MAINLY PARTS OF NORTHEASTERN WYOMING AND NORTHWESTERN SOUTH
DAKOTA. LL CAA AND A TIGHT SFC PRESSURE GRADIENT POINT TO A WINDY
DAY ON THURSDAY. HIGHS ON THURSDAY WILL BE NOTICEABLY COOLER AND
OVERNIGHT LOW TEMPS WILL BE COLD ENOUGH TO INCLUDE A MENTION OF
-SHSN.

FRIDAY...A LULL IN THE WEATHER IS EXPECTED AS AN UPPER LEVEL RIDGE
CROSSES THE NRN PLAINS. LOOKING AHEAD TO NEXT WEEKEND...GFS/ECMWF
BRING ANOTHER LOW PRESSURE SYSTEM INTO THE AREA...BUT THIS TIME
MOVING IT FROM THE CENTRAL ROCKIES INTO THE CENTRAL PLAINS...A TRACK
THAT COULD BRING WIDESPREAD RAIN ON SATURDAY AND SUNDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 510 PM MDT SUN APR 20 2014

GUSTY NORTHWEST WINDS CURRENTLY ACROSS THE AREA WILL DIMINISH
THIS EVENING. ISOLATED SHOWERS AND THUNDERSTORMS WILL TRACK ACROSS
SOUTH CENTRAL SOUTH DAKOTA THROUGH EARLY EVENING WITH LCL MVFR
VSBY AND ERRATIC WINDS. OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH
MONDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...15
LONG TERM...10
AVIATION...7





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