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000
FXUS63 KABR 200526 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1226 AM CDT MON MAY 20 2013

.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH MONDAY
FORECAST CHALLENGES INCLUDE TIMING/COVERAGE OF PRECIPITATION.

CURRENTLY...THERE ARE THREE DISTINCT CIRCULATIONS ROTATING AROUND
WITHIN A MUCH LARGER/BROADER UPPER LEVEL LONGWAVE TROF. THIS CWA
FINDS ITSELF NESTLED IN BETWEEN ALL OF THEM...WITH SUNSHINE
WORKING TO MIX THE BOUNDARY LAYER OUT THIS AFTERNOON. TEMPERATURES
RANGE FROM THE MID 50S ACROSS THE FAR WESTERN FORECAST ZONES UNDER
CONTINUED OVERCAST SKYCOVER...WHILE READINGS ACROSS THE FAR
EASTERN FORECAST ZONES ARE IN THE LOW TO MID 70S UNDER A PARTLY TO
MOSTLY SUNNY SKY. THE CENTRAL AND WESTERN TWO-THIRDS OF FORECAST
ZONES HAVE PICKED UP ANYWHERE FROM 1 TO 4+ INCHES OF RAINFALL THE
PAST TWO NIGHTS. IF TRUE CONVECTION APPEARS TO BE WRAPPING BACK
INTO THAT AREA OVERNIGHT...THERE COULD BE SOME HYDRO CONCERNS.

LATE THIS AFTERNOON THROUGH TONIGHT...CONTINUING TO WATCH THE
SATELLITE/RADAR TRENDS FOR HEAT-OF-THE-DAY SHOWERS AND
THUNDERSTORMS. NOT EXPECTING ALL THAT MUCH IN THE WAY OF SEVERE
WEATHER THIS AFTERNOON OR TONIGHT. THERE COULD BE ONE OR TWO
PULSE STORMS CAPABLE OF PRODUCING MARGINALLY SEVERE HAIL...AS
0-6KM SHEAR CONTINUES TO REMAIN RATHER LOW. WHAT`S MORE...THERE
COULD EVEN BE AN ISOLATED LANDSPOUT SIGHTING THROUGH EARLY THIS
EVENING IF THUNDERSTORMS DEVELOP IN/ON ANY OF THE SURFACE TROFS
POSITIONED OVER THE CWA. OVERALL...SHOULD BE DEALING MAINLY WITH
THE POTENTIAL FOR SOME MORE SLOW-MOVING...EFFICIENT PRECIPITATION
PRODUCING CONVECTION FROM LATE THIS EVENING THROUGH TOMORROW
MORNING. MOST OF THE CAM SOLUTIONS ARE GENERATING WHAT APPEARS TO
BE A TROWAL-LIKE SIGNATURE OF LIGHT TO MODERATE RAIN SHOWERS
TONIGHT MAINLY EAST OF A LINE FROM MILLER TO ABERDEEN. WITH MORE
CLOUDS THAN CLEAR SKY EXPECTED OVERNIGHT...TEMPERATURES SHOULD NOT
FALL OFF ALL THAT MUCH WITH LOWS IN THE 50S AND 60S.

MONDAY...WILL BE DEALING WITH ANOTHER NEARLY STATIONARY UPPER
CIRCULATION SPINNING OVER THE CWA...KEEPING THINGS PLENTY CLOUDY
WITH POCKETS OF RAIN AND DRIZZLE EXPECTED TO BE AROUND THROUGH THE
MORNING HOURS...BEFORE DAYTIME HEATING HAS A CHANCE TO POTENTIALLY
INITIATE ADDITIONAL AFTERNOON CONVECTION ACROSS THE FAR EASTERN
FORECAST AREA. RAIN COOLED BOUNDARY LAYER TEMPERATURES AND PLENTY
OF CLOUDS EXPECTED AROUND ON MONDAY SHOULD KEEP THE LID ON
TEMPERATURES...WITH HIGH TEMPERATURES EXPECTED TO BE ONLY IN THE
50S AND 60S.


.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MONDAY THROUGH WEDNESDAY WE WILL CONTINUE TO SEE IMPACTS FROM SLOW
MOVING UPPER LEVEL LOW PRESSURE SYSTEM...THOUGH ATMOSPHERIC
PROFILES HAVE BECOME LESS UNSTABLE AS SYSTEM BECOMES WELL MIXED
AND MORE BAROTROPIC. THOUGH LACKING INSTABILITY...THERE WILL BE
PLENTY OF MOISTURE ALOFT AND BOTH ECMWF AND GFS SUGGEST SOME WEAK
MID LEVEL LIFT...ON THE ORDER OF ABOUT 5 MICROBARS AT
MAXIMUM...WHICH WOULD SUGGEST A FEW LIGHT SHOWERS PERSISTING INTO
EARLY WEDNESDAY. CLOUD COVER/SHOWERS WILL ALSO INHIBIT HEATING SO
TEMPERATURES WILL REMAIN A FEW DEGREES BELOW CLIMO FOR
HIGHS...ABOUT NORMAL FOR LOWS.

DECENT AGREEMENT CONTINUES BETWEEN LONG TERM DETERMINISTIC
GUIDANCE WITH UPPER LOW REPLACED BY WEAK RIDGE ALOFT FOR THE
LATTER HALF OF THE WORK WEEK...THOUGH RETURN FLOW WILL BEGIN TO
DEVELOP BY FRIDAY...WITH INCREASING H85 TEMPERATURES AND STEADILY
INCREASING LOW LEVEL DEWPOINTS. UPPER TROF BEGINS TO MOVE ACROSS
THE NORTHERN ROCKIES FOR THE WEEKEND...INDUCING SOUTHWEST FLOW
ALOFT. PROFILES NEAR THE END OF THE RUN IN BUFKIT SUGGEST SOME
INSTABILITY ALOFT...THOUGH THIS FAR OUT ITS HARD TO DETERMINE THE
THUNDERSTORM POTENTIAL SO WILL STICK WITH DAILY 20 TO 40 POPS.


&&

.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

LARGE UPPER LEVEL CIRCULATION ACROSS THE NORTHERN PLAINS WITH
SEVERAL LARGE VORT CENTERS EMBEDDED WITHIN IT WILL BRING NUMEROUS
SHOWERS ALONG WITH SOME THUNDER TO THE REGION TONIGHT INTO MONDAY.
EXPECT ALL TERMINALS TO BE AFFECTED BY SHOWERS THROUGH THE TAF PERIOD.
OTHERWISE...IFR/MVFR CEILINGS ARE EXPECTED TO DEVELOP AT ALL
TERMINALS TONIGHT AND REMAIN THROUGH MONDAY. MBG IS ALSO EXPECTED
TO HAVE SOME IFR/MVFR FOG THROUGH THE NIGHT.





&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
UPDATE...WISE
SHORT TERM...DORN
LONG TERM...CONNELLY
AVIATION...WISE

WEATHER.GOV/ABERDEEN