Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 030840
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
240 AM MDT FRI JUL 3 2015

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 231 AM MDT FRI JUL 3 2015

08Z SURFACE ANALYSIS HAD WEAK HIGH PRESSURE OVER THE CWA. SOME
BR/FU FROM EAST CENTRAL MT INTO EASTERN NE...SHOULD LAST UNTIL
EARLY MORNING AND THEN MIX OUT AS DIURNAL HEATING CYCLE BEINGS.
LOOKING UPSTREAM...WATER VAPOUR HAD SHORTWAVE OVER CENTRAL MT
WHICH IS TAPPING INTO WEAK MUCAPE FOR ISOLATED -SHRA/TS. ACTIVITY
SHOULD DISSIPATE BEFORE IT REACHES THE CWA THIS MORNING. IT MAY BE
FOCUS FOR LATE AFTERNOON/EARLY EVENING -TSRA AS 0.5-1KJ/KG MLCAPE
DEVELOPS ALONG WITH 25-75J/KG MLCIN. SURFACE REFLECTION OF
SHORTWAVE FORECAST TO BE WEAK AS SURFACE RIDGE SHIFTS EAST.
EXPANDED LOW POPS FROM THE BLACK HILLS TO SOUTHEAST PERIPHERY OF
SHORTWAVE FOR LATE THIS AFTERNOON/EARLY THIS EVENING. TEMPERATURES
WILL BE NEAR GUIDANCE THIS AFTERNOON.

TONIGHT...WARM AIR ADVECTION EXPECTED WITH TYPICAL LOWER TROPOSPHERIC
RESPONSE IN THE FORM OF WEAK LOW LEVEL JET/THETA-E ADVECTION. WITH
SHORTWAVE PASSING TO OUR EAST AND IMPLIED SUBSIDENCE BEHIND
IT...LEFT FORECAST DRY...BUT WOULDN/T BE SURPRISE TO SEE ACCAS.
TEMPERATURES NEAR GUIDANCE IN THE WEST/SLIGHTLY ABOVE IN THE EAST.

SATURDAY...LOW PRESSURE WILL EXTEND FROM NORTHEAST MT INTO EASTERN
CO...AND TROUGH INTO CENTRAL NE. THIS MAY BE FOCUS FOR MAINLY
AFTERNOON/EVENING TSRA ACTIVITY WITH 1-2KJ/KG MLCAPE AVAILABLE. 0-
6KM BULK SHEAR WILL BE SUFFICIENT FOR ISOLATED SEVERE
TSRA...ESPECIALLY OVER SOUTHWEST SD AS TERRAIN AND TROUGH INTERACT.
ACTIVITY SHOULD BE FOCUSED DURING PEAK HEATING WITH 25-75J/KG MLCIN.
AS UPPER TROUGH OVER WESTERN CANADA SWINGS INTO CENTRAL CANADA...SURFACE
COLD FRONT WILL ENTER FAR NORTHWEST REACHES OF THE CWA LATE SATURDAY
NIGHT. TEMPERATURES WILL BE QUITE WARM SATURDAY AFTERNOON.

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 231 AM MDT FRI JUL 3 2015

A STRONG SHORTWAVE WILL CROSS FLATTENED CYCLONIC FLOW ACROSS THE
NRN PLAINS SUNDAY. A STRONG COLD FRONT WILL CONTINUE TO CROSS THE
AREA SUNDAY INTO SUNDAY NIGHT...BRINGING INCREASING CHANCES OF
STORMS ACROSS THE CWA. WITH STRONG SHEAR AHEAD OF THE BOUNDARY AND
STRONG LOW LEVEL FORCING WITH THE FROPA...COULD SEE SOME SEVERE
STORMS DEVELOP.

DRIER NW FLOW WILL KEEP EARLY NEXT WEEK DRY...THOUGH A FEW STORMS
WILL BE POSSIBLE TUE OVER NE WY/BLKHLS. COOLER TEMPS MON/TUE WILL
BECOME MORE SEASONAL THROUGH MID WEEK AS UPPER FLOW BECOMES MORE
ZONAL. WAVES PASSING THROUGH THE AREA WILL BRING DAILY CHANCES OF
STORMS TO THE AREA FOR THE SECOND HALF OF THE WEEK.

&&

.AVIATION...FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT
ISSUED AT 231 AM MDT FRI JUL 3 2015

VFR CONDITIONS GENERALLY EXPECTED TODAY AND TONIGHT. ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE MAINLY ACROSS THE
BLKHLS AREA THIS AFTN AND EARLY EVNG. LOCAL MVFR CONDITIONS ARE
POSSIBLE WITH ANY HEAVIER PRECIP.

&&

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

$$

SHORT TERM...HELGESON
LONG TERM...13
AVIATION...13


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