000
FXUS63 KUNR 191623
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1023 AM MDT SUN MAY 19 2013

.UPDATE...
ISSUED AT 1021 AM MDT SUN MAY 19 2013

UPPER LOW OVER CENTRAL DAKOTAS WITH LARGE BAND OF RAIN MOVING
AROUND THE LOW FROM ND INTO NWRN SD. RAIN OVER THE NORTHERN BLACK
HILLS IS UPSLOPE ENHANCED. SURFACE LOW NEAR ABR WITH STRONG
PRESSURE GRADIENT ACROSS WESTERN SD AND INCREASING NW WINDS.
TEMPERATURES WILL NOT WARM MUCH TODAY.

&&

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

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.
&&

$$

UPDATE...WFO UNR
LONG TERM...26
AVIATION...26