Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 251718
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1118 AM MDT FRI JUL 25 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 212 AM MDT FRI JUL 25 2014

SHORTWAVE IS MOVING INTO EASTERN SD THIS MORNING...ALONG WITH AN
AREA OF THUNDERSTORMS. SKIES ARE CLEARING OVER FORECAST AREA...
WITH JUST A FEW LEFT OVER SOUTH CENTRAL SD...AND SOME PATCHY LOWER
CLOUDS BETWEEN LEM AND D07. SURFACE FRONT EXTENDS FROM CENTRAL ND-
LOW OVER CENTRAL SD-SOUTHWESTWARD. NORTHWEST WINDS HAVE BEEN
GUSTING TO 30-40 KT BRIEFLY BEHIND FRONT...AND WILL CONTINUE THE
WIND ADVISORY UNTIL 5 AM MDT. SURFACE HIGH WILL BUILD INTO WESTERN
SD THIS MORNING...SO THE WINDS WILL DECREASE QUICKLY...AND BRING
COOLER AIR TO THE AREA. FAST ZONAL FLOW OVER THE NORTHERN PLAINS
TODAY...BUT AS DEEP UPPER LOW MOVES SOUTHEASTWARD FROM CANADA
TOWARD THE GREAT LAKES AND RIDGE BUILDS OVER THE ROCKIES...
FORECAST AREA WILL BE UNDER CYCLONIC NORTHWEST FLOW FOR THE
WEEKEND. BROAD THETA-E RIDGE WILL BUILD ALONG AN INVERTED TROF
NORTHWARD FROM LOW OVER SOUTHEASTERN WY-NE PANHANDLE...BRUSHING
OVER THE SOUTHERN PART OF OUR WY FORECAST AREA AND CROSSING FAR
SOUTHERN SD TONIGHT. CURRENT MODELS HAVE DECREASED CAPE OVER SOUTH
CENTRAL SD...SO HAVE LOWERED POPS NORTH OF I-90. STILL SOME WEAK
CAA SATURDAY AS ANOTHER HIGH PUSHES INTO THE NORTHERN PLAINS...
WITH TEMPERATURES A FEW DEGREES COOLER.

&&

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 212 AM MDT FRI JUL 25 2014

A HIGH LATTITUDE BLOCKING PATTERN WITH FULL LATTITUDE RIDGING
OVER WESTERN NORTH AMERICA WILL DOMINATE THE LARGE SCALE MAPS FROM
SUNDAY THROUGH NEXT WEEK. FOR THE NORTHERN HIGH PLAINS THE RIDGE
WILL BE FAR ENOUGH WEST TO KEEP A NORTHWEST FLOW ALOFT IN PLACE.
THE MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT SHOWING WEAK
SHORT WAVE ENERGY BREAKING THROUGH THE RIDGE AND CROSSING THE
FORECAST AREA MONDAY NIGHT THROUGH EARLY WEDNESDAY. UPPER LEVEL
SUPPORT APPEARS TO BE SIGNIFICANT ENOUGH FOR SCATTERED
THUNDERSTORMS MOST OF THE DAY TUESDAY ESPECIALLY OVER SOUTHWESTERN
SOUTH DAKOTA AND NORTHEAST WYOMING. HOWEVER STABLE MID LEVELS AND
RATHER DRY LOW LEVELS MAY KEEP SHOWER ACTIVITY SUBDUED.
TEMPERATURES ARE FORECAST TO BE A LITTLE BELOW NORMAL ALL WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY)
ISSUED AT 1118 AM MDT FRI JUL 25 2014

ISOLATED TO SCATTERED STORMS ARE POSSIBLE TONIGHT OVER CENTRAL
SOUTH DAKOTA. OTHERWISE VFR CONDITIONS ARE EXPECTED THROUGH THE
FORECAST PERIOD.

&&

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

$$

SHORT TERM...55
LONG TERM...CARPENTER
AVIATION...13





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