National Weather Service Text Product Display

Area Forecast Discussion
Issued by NWS Rapid City, SD

Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46

000
FXUS63 KUNR 152024
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
224 PM MDT WED MAY 15 2013

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 212 PM MDT WED MAY 15 2013

CURRENT SURFACE MAP PLACES NARROW AXIS OF HIGH PRESSURE ACROSS
EASTERN MONTANA INTO SOUTHERN MINNESOTA/NORTHERN IOWA. WEAK
RETURN FLOW ACROSS NORTHEAST WYOMING/SOUTHWEST SOUTH DAKOTA HAS
BEEN SLOW TO INCREASE BOUNDARY LAYER MOISTURE. THUNDERSTORMS ARE
DEVELOPING ACROSS HIGHER TERRAIN OF WESTERN WYOMING AHEAD OF UPPER
LEVEL SHORTWAVE. SHORTWAVE CROSSES EASTERN WYOMING INTO WESTERN
SOUTH DAKOTA OVERNIGHT. WITH STEEP MID LEVEL LAPSE RATES...NAM/RUC
INDICATING MUCAPE OF 100-400J/KG...SCATTERED THUNDERSTORMS
EXPECTED OVERNIGHT INTO THURSDAY MORNING. MAY BE A BREAK IN
THUNDERSTORMS ACROSS WESTERN HALF OF FORECAST AREA IN THE
MORNING...WITH ADDITIONAL THUNDERSTORMS POSSIBLE THURSDAY
AFTERNOON. WITH MARGINAL CAPE AND WEAK SHEAR...SEVERE
THUNDERSTORMS NOT EXPECTED.

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 212 PM MDT WED MAY 15 2013

UPPER RIDGE SHIFTS AS A DEEP UPPER TROF DIGS DOWN THE WESTERN CONUS
COAST RESULTING IN A SOUTHWEST FLOW PATTERN. SEVERAL SHORTWAVES
AHEAD OF THE TROF WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS.
DECENT INSTABILITY AND SHEAR PROFILES SUGGEST THE FIRST REAL ROUND
OF SEVERE WEATHER FOR THE FORECAST AREA ON FRIDAY AND SATURDAY. MODEL
DEWPOINTS ARE MAINLY IN THE 50S...HOWEVER THE NAM IS SUGGESTING
DEW POINT VALUES IN THE LOWER 60S. AT THIS TIME WILL GO WITH MODEL
CONSENSUS. PRECIP CHANCES WILL CONTINUE THROUGH MONDAY
NIGHT/TUESDAY AS THE COOLER AIRMASS WORKS ITS WAY INTO THE AREA.
MODELS FOR EARLY NIGHT WEEK DIFFER SOME ON THE TIMING AND POSITION
OF THE UPPER LOW WHEN IT CLOSES OFF. HOWEVER...ALL SOLUTIONS
INDICATE PRECIP CONTINUING ACROSS THE NORTHERN PLAINS.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON
ISSUED AT 212 PM MDT WED MAY 15 2013

MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THURSDAY MORNING.
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
BEGIN LATE THIS AFTERNOON ACROSS NORTHEAST WYOMING AND PUSH ACROSS
SOUTH DAKOTA TONIGHT INTO EARLY THURSDAY MORNING. GUSTY WINDS AND
MVFR CONDITIONS CAN BE EXPECTED AROUND SHOWERS AND STORMS.

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

$$

SHORT TERM...7
LONG TERM...MLS
AVIATION...MLS

National Weather Service Weather Forecast Office