000
FXUS63 KUNR 122107
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
307 PM MDT WED JUN 12 2013

.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 218 PM MDT WED JUN 12 2013

CURRENT SURFACE ANALYSIS PLACES HIGH OVER THE WRN DAKOTAS WITH
LOW OVER THE NORTHERN ROCKIES. UPPER LEVEL ANALYSIS PLACES RIDGE
AXIS NEAR THE MONTANA/DAKOTA BORDER WITH BROAD LOW OFF THE PACIFIC
NORTHWEST. A VARIETY OF WEAK DISTURBANCES ROTATING UP AHEAD OF THE
UPPER LOW CONTINUES TO PRODUCE A FEW SMALL AREAS OF CONVECTION OVER
PTNS OF WRN MT/WY.

FOR TONIGHT...RIDGE AXIS SLOWLY SCOOTS EAST A BIT WITH UPPER FLOW
BECOMING SWRLY OVER FAR WRN CWA. WITH WEAK DISTURBANCES MOVING
THROUGH MAY SEE A FEW THUNDERSTORMS DEVELOP OVER NERN WY INTO
PORTIONS OF FAR WRN SD. ALTHOUGH DEEP LAYER SHEAR WILL BE QUITE
STRONG...INSTABILITY WILL BE MODEST AT BEST. THEREFORE DO NOT
EXPECT MUCH IN THE WAY OF SEVERE...THOUGH A STORM OR TWO GETTING
STRONG WILL NOT BE OUT OF THE QUESTION...PARTICULARLY NEAR THE
MT/WY BORDER.

ON THURSDAY...RIDGE AXIS CONTINUES TO SLIDE EAST AS UPPER LOW/TROF
PUSHES TOWARDS THE ROCKIES ALLOWING A VARIETY OF WAVES TO LIFT
THROUGH SOUTHWESTERLY FLOW. SURFACE LOW SHIFT FROM SERN MT INTO
NERN WYOMING THROUGH THE AFTERNOON/EVE WITH PRESSURE GRADIENT
TIGHTENING OVER THE AREA BRINGING BREEZY SERLY WINDS. EXPECT SCT
THUNDERSTORMS TO DEVELOP IN THE AFTERNOON/EVENING MAINLY OVER THE
WRN/CTRL PARTS OF THE CWA WITH FOCUS SHIFTING MORE TO THE
NORTH/EAST OVERNIGHT WITH INCREASING LOW LEVEL JET/THETA-E
ADVECTION. SEVERE STORMS WILL BE POSSIBLE WITH INSTABILITY
INCREASING (1000-2500 J/KG) AND PLENTY OF 0-6 KM BULK SHEAR (45
KT+).

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 218 PM MDT WED JUN 12 2013

SOUTHWEST FLOW ON FRIDAY TRANSITIONS TO RIDGING FOR THE
WEEKEND...THEN BACK TO SOUTHWEST FLOW FOR EARLY NEXT WEEK.
THUNDERSTORM CHANCES CONTINUE THROUGH MUCH OF THE PERIOD...WITH THE
EXCEPTION OF SATURDAY INTO EARLY SUNDAY...WHEN RIDGING IS STRONGEST.
TEMPERATURES WILL REMAIN AT OR ABOVE AVERAGE THROUGH THE PERIOD.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON
ISSUED AT 218 PM MDT WED JUN 12 2013

OTHER THAN A FEW POCKETS OF LINGERING MVFR CIGS...MAINLY
OVER THE BLACK HILLS AREA...VFR CONDITIONS ARE EXPECTED ACROSS THE
REGION. ANOTHER MID LEVEL IMPULSE IN SW FLOW MAY SUPPORT ISOLD TS
LATE THIS AFTERNOON OVER NORTHEAST WY AND THE BLACK HILLS.

&&

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

$$

SHORT TERM...77
LONG TERM...15
AVIATION...15