Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 070522
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1122 PM MDT SUN JUL 6 2014

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 153 PM MDT SUN JUL 6 2014

LOCAL RIDGE FLATTENING WILL CONTINUE THROUGH THE PERIOD AS A
FAIRLY STRONG IMPULSE ADVECTS SOUTHEAST THROUGH THE SOUTHERN
CANADIAN PRAIRIE PROVINCES AND THE NORTHERN PLAINS. THIS FEATURE
WILL SUPPORT INCREASING CHANCES FOR SHRA/TS TONIGHT INTO MIDDAY
MONDAY...WITH A COLD FRONT ADVECTING THROUGH THE AREA MONDAY.

DEPARTING IMPULSE AND ASSOCIATED HIGH BASED CONVECTION NEAR ICR
/19Z/...IS GIVING WAY TO LARGE SCALE SINK OVER THE FA SYNOPTICALLY.
MID-RIDGE CONVERGENCE COUPLED WITH LINGERING LL MOISTURE MAY STILL
YET SUPPORT AN ISOLD SHOWER OVER THE CENTRAL BLACK HILLS INTO EARLY
EVENING. OTHERWISE...ATTENTION TURNS TOWARD THE NEXT UPPER LEVEL
SHORTWAVE TROUGH APPROACHING FROM THE WEST. A FEW HIGH BASED SHOWERS
MAY DEVELOP OVER WY/MT LATE THIS AFTERNOON AND ADVECT INTO WESTERN
FA AHEAD OF THIS DISTURBANCE. HOWEVER...IT WILL LIKELY BE ELEVATED
FORCING AND HIGH CENTERED POS THETA-E ADV AT THE BASE OF STEEP MID
LEVEL LAPSE RATES THAT SUPPORTS CONVECTIVE SHRA WITH THIS SYSTEM.
FORECAST MODELS HAVE BEEN ALL OVER THE BOARD WRT TRACK/STRENGTH/AND
PRECIP DEVELOPMENT WITH THIS SYSTEM...MAKING IT DIFFICULT TO
DELINEATE A LOCALIZED AREA OF BEST FORCING FOR ASCENT.
HENCE....GIVEN STEEP MID LEVEL LAPSE RATES AND RESULTING ELEVATED
CAPE/A DEVELOPING LLJ/AND WIDESPREAD POS THETA-E ADV
OVERNIGHT...OPTED FOR A LOW CHANCE POP MENTION ALL PLACES IN THE
FA THROUGH MONDAY MORNING...WITH SLIGHTLY HIGHER NUMBERS OVER
SCENTRAL SD WHERE SLIGHTLY BETTER MOISTURE/FORCING WILL BE FOUND.
UPPER WAVE AND ASSOCIATED LSA WILL QUICKLY TREND SOUTH...WITH
SHRA/TS CHANCES SHIFTING SOUTH ACROSS THE FA. MOST PLACES WILL
LIKELY SEE DRY CONDITIONS BY MONDAY AFTERNOON. HOWEVER...HAVE KEPT
LOW POPS ACROSS MOST AREAS THROUGH AFTERNOON GIVEN CYCLONIC FLOW
ALOFT AND STEEP LL LAPSE RATES. A FEW RESIDUAL DIURNAL SHRA MAY
LINGER OVER THE FAR SOUTH MONDAY EVENING...WITH THINGS QUICKLY
DRYING OUT OVERNIGHT MONDAY.

SFC COLD FRONT EXPECTED MONDAY HAS TRENDED A LITTLE STRONGER IN
FORECAST MODELS. WITH COOLER THERMAL FIELDS PROGGED. HAVE DROPPED
TEMPS A FEW DEGREES ALL AREAS. CAA REGIME WITH SFC PRESSURE RISES
AND DEEP MIXING WILL ALLOW A PERIOD OF BREEZY CONDITIONS ACROSS MOST
OF THE SD PLAINS...ESP NW AREAS.

&&

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 153 PM MDT SUN JUL 6 2014

NORTHWESTERLY FLOW ALOFT WILL REMAIN PERSISTENT THROUGH THE MIDDLE
PART OF THE WEEK...WITH RIDGING OVER THE ROCKIES AND WEST COAST
STATES. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE FROM
WEDNESDAY THROUGH FRIDAY AND LIKELY CONTINUE INTO THE WEEKEND AS THE
RIDGE TO THE WEST SLIDES EASTWARD INTO THE PLAINS AND EVENTUALLY
FLATTENS OUT. CHANCES FOR STRONG TO SEVERE STORMS WILL ALSO INCREASE
LATER IN THE WEEK AS SOUTH TO SOUTHEAST FLOW AT THE SURFACE BRINGS
INCREASING MOISTURE AND INSTABILITY TO THE AREA. TEMPERATURES WILL
BE NEAR AVERAGE TUESDAY...WITH A GRADUAL WARMING TREND THROUGH THE
MIDDLE AND LATTER PART OF THE WEEK AS THE THERMAL RIDGE BUILDS INTO
THE PLAINS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1121 PM MDT SUN JUL 6 2014

VFR CONDITIONS WILL GENERALLY CONTINUE THROUGH MONDAY. ISOLATED
TSRA WILL OCCUR OVERNIGHT AND PERSIST MONDAY MORNING AS A
DISTURBANCE SLIDES SOUTHEAST THROUGH THE REGION.

&&

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

$$

SHORT TERM...JC
LONG TERM...26
AVIATION...HELGESON



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