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000
FXUS63 KUNR 191145
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
545 AM MDT SUN MAY 19 2013

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 242 AM MDT SUN MAY 19 2013

A CLOSED LOW HAS SET UP OVER EAST CENTRAL SOUTH DAKOTA
THIS MORNING.  SATELLITE IMAGERY SHOWS THE DEVELOPMENT OF A LARGE
BAND OF CLOUDS WRAPPING AROUND THE LOW TO THE NORTH AND WEST INTO A
WELL DEVELOPED COMMA WHICH IS EXTENDING INTO NORTHWEST SOUTH DAKOTA
AND SURROUNDING AREAS. A PERSISTENT BAND OF LIGHT TO MODERATE
SHOWERS ARCING SOUTHWARD FROM NORTH DAKOTA HAS BEGUN TO SLOWLY
EXPAND IN AREA AND NOW COVERS MOST OF WESTERN SOUTH DAKOTA.

TODAY THROUGH MONDAY...STRONG THETA E ADVECTION IN THE CYCLONIC FLOW
INTO WESTERN SOUTH DAKOTA WILL CONTINUE FOR MOST OF THE NEXT TWO
DAYS. THIS FLOW COMBINED WITH AN ALREADY SATURATED AIRMASS AND AN
UPSLOPE GRADIENT WILL SUPPORT CONTINUOUS PRECIPITATION OVER WESTERN
SOUTH DAKOTA THROUGH MONDAY AND BEYOND. THE NORTHERN BLACK HILLS IS
THE AREA OF CONCERN THROUGH MONDAY BECAUSE THE UPSLOPE ENHANCEMENT
SHOULD BE GREATEST IN THIS AREA.  WILL ISSUE A HYDROLOGIC OUTLOOK
FOR THIS SITUATION LATER THIS MORNING...AND WOULD EXPECT SOME TYPE
OF FLOOD WATCH FOR THAT AREA LATER TODAY. OTHERWISE THE ADVANCING
PACIFIC AIRMASS WILL RESULT IN MAXIMUM TEMPERATURES ABOUT 10 DEGREES
COOLER THAN YESTERDAY...AND THEN DROPPING SEVERAL MORE DEGREES
MONDAY AND TUESDAY.  GUSTY NORTHERLY WINDS ARE EXPECTED TO DEVELOP
IN THE CYCLONIC FLOW AROUND THE EASTERN SOUTH DAKOTA LOW CENTER LATE
TODAY AND CONTINUE THROUGH MONDAY.  WIND SPEEDS ARE EXPECTED TO
REMAIN BELOW ADVISORY CRITERIA.

&&

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 242 AM MDT SUN MAY 19 2013

SHOWERS WILL REMAIN AROUND THE AREA ON TUESDAY AS UPPER LOW IS
PROGGED TO BE SOMEWHERE OVER EASTERN SD DURING THE DAY. THE HEAVIEST
RAINFALL POTENTIAL ON TUESDAY WILL LIKELY BE ACROSS THE NORTHERN
BLACK HILLS...WHERE MOIST UPSLOPE FLOW WILL CONTINUE...ESPECIALLY IN
THE MORNING. ELSEWHERE...SHOWERS SHOULD BEGIN TO TAPER OFF IN
INTENSITY...AND EVENTUALLY IN COVERAGE AS WELL...TUESDAY INTO
TUESDAY NIGHT. MEDIUM RANGE MODELS IN PRETTY GOOD AGREEMENT WITH LOW
FINALLY SHIFTING EASTWARD ACROSS THE UPPER MIDWEST TUESDAY NIGHT AND
WEDNESDAY...WITH SHOWERS GENERALLY DISSIPATING FROM WEST TO EAST
ACROSS THE CWA DURING THIS TIME.

WEAK RIDGING BEHIND EXITING SYSTEM WILL BRING MOSTLY DRY CONDITIONS
LATER WEDNESDAY INTO THURSDAY. A GRADUAL WARMUP IS EXPECTED LATE IN
THE WEEK...WITH TEMPERATURES BACK TO NEAR TO ABOVE AVERAGE LEVELS BY
THE WEEEKEND. SOUTHWEST FLOW ALOFT WILL DEVELOP AGAIN BY THE END OF
THE WEEK...SO WILL SEE CHANCES FOR SHOWERS AND THUNDERSTORMS
INCREASE THURSDAY NIGHT INTO NEXT WEEKEND.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 544 AM MDT SUN MAY 19 2013

SCATTERED TO NUMEROUS SHOWERS WILL CONTINUE THIS MORNING OVER MUCH
OF WESTERN SOUTH DAKOTA AND FAR NORTHEASTERN WYOMING...WITH AREAS OF
MVFR/IFR CONDITIONS. RAIN SHOWERS WILL BECOME MORE WIDESPREAD THIS
AFTERNOON WITH A FEW EMBEDDED THUNDERSTORMS POSSIBLE...ESPECIALLY
TOWARD SOUTH CENTRAL SD. MVFR/IFR CIGS WILL BECOME FAIRLY WIDESPREAD
ACROSS THE AREA BY THE EVENING. RAIN WILL CONTINUE TONIGHT...
ESPECIALLY ACROSS THE NORTHERN BLACK HILLS INTO PORTIONS OF
NORTHEASTERN WY AND NORTHWESTERN SD. WIDESPREAD MVFR/IFR CONDITIONS
ARE EXPECTED OVERNIGHT.

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

$$

SHORT TERM...CARPENTER
LONG TERM...26
AVIATION...26