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000
FXUS63 KABR 260619 AAC
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
119 AM CDT SUN MAY 26 2013

.UPDATE...
SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.

SPC HAS COORDINATED SEVERE THUNDERSTORM WATCH 221 FOR MUCH OF THE
WESTERN HALF OF THE CWA IN EFFECT UNTIL 14Z. UPDATED PRODUCTS ARE
BEING SENT.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
THE POTENTIAL FOR SEVERE STORMS OVER THE NEXT COUPLE OF DAYS WILL
BE THE MAIN FORECAST CHALLENGE.

AN UPPER LEVEL JET MAX OVER NORTHEAST WYOMING...ALONG WITH WAA IN
THE MID LEVELS IS PRODUCING SCT THUNDERSTORMS ACROSS NW SOUTH
DAKOTA AND WESTERN NORTH DAKOTA. THESE STORMS ARE OCCURRING IN A
STRONG INSTABILITY AXIS WITH MU-CAPE VALUES EXCEEDING 2K J/KG.
WITH FAIRLY GOOD 0-6 KM BULK VALUES...BELIEVE A FEW STRONG TO
SEVERE STORMS COULD IMPACT NORTH CENTRAL SOUTH DAKOTA THROUGH THE
LATE AFTERNOON HOURS. WITH AN E-NE STORM MOTION...THESE STORMS
SHOULD ONLY AFFECT A FEW COUNTIES IN NC SOUTH DAKOTA.

ADDITIONAL THUNDERSTORMS ARE EXPECTED TO DEVELOP AROUND THE BLACK
HILLS REGION WHERE UP-SLOPE MID LEVEL MOISTURE WILL INTERACT THE
THE ABOVE MENTIONED UPPER LEVEL JET MAX. THE NAM12 ALONG WITH
MESOSCALE ANALYSIS IS SUGGESTING H7 MOISTURE IS POOLING NEAR THE
BLACK HILLS...WITH THE AXIS SLOPING E-SE INTO EASTERN NEBRASKA.
THIS MID LEVEL INSTABILITY AXIS IS THE LIKELY LOCATION FOR AN MCS
TO DEVELOP DURING THE OVERNIGHT HOURS. AT THIS TIME BELIEVE THE
MCS WOULD MAINLY AFFECT THE SOUTHWEST PORTION OF THE CWA...OR
ALONG AND SOUTH OF PIERRE TO MILLER. DAMAGING WINDS AND HAIL WOULD
BE THE MAIN THREAT.

BASED ON SOME OF THE HI-RES MODEL SOLUTIONS...A BETTER PORTION OF
THE DAY ON SUNDAY SHOULD BE DRY...WITH PERHAPS SOME LEFT OVER
CONVECTION DURING THE MORNING HOURS. BOTH THE 06Z AND 12Z MODEL
RUNS OF THE NMM/ARW SHOW LITTLE TO NO CONVECTIVE DEVELOPMENT
REACHING THE CWA UNTIL AFTER 3Z. THUS HAVE TRIED TO REMOVE POPS
FOR MOST THE DAY WHILE MAINTAINING A GOOD AGREEMENT WITH
SURROUNDING WFOS.

CHANCES FOR THUNDERSTORMS BEYOND SUNDAY NIGHT IS A BEST GUESS AT
THIS TIME. VIRTUALLY ALL THE MODELS ARE SUPPORTIVE OF MULTIPLE
ROUNDS OF STORMS WITH THE BEST POTENTIAL FOR SEVERE WEATHER
OCCURRING ON MONDAY. THIS IS WHEN THE STRONGEST SHORT WAVE WILL
MOVE ACROSS THE REGION DURING PEAK HEATING. DECENT CAPE AND BULK
SHEAR VALUES ARE SUGGESTIVE OF SEVERE STORMS FOR MEMORIAL DAY.


.LONG TERM...TUESDAY THROUGH SATURDAY
THE MODELS SHOW GOOD AGREEMENT AND HAVE BEEN CONSISTENT WITH
ANOTHER LARGE UPPER LEVEL LOW PRESSURE TROUGH AFFECTING THE REGION
THROUGH THE ENTIRE LONG TERM. TO BEGIN THE PERIOD...A LARGE
NEGATIVELY TILTED TROUGH WILL BE DIGGING INTO THE SOUTHWEST US AS
A STRONG JET STREAK DIVES IN FROM THE PACIFIC. THIS TROUGH WILL
LIFT SLOWLY NORTHEAST THROUGH THURSDAY WITH AN UPPER LEVEL
CIRCULATION CLOSING OFF OVER THE NORTHERN ROCKIES. THIS UPPER
LEVEL CIRCULATION WILL SLOWLY MOVE EAST INTO THE NORTHERN PLAINS
INTO THE WEEKEND. THUS...WITH THIS SETUP WITH SEVERAL SHORT WAVES
LIFTING ACROSS THE REGION ALONG WITH THE SLOW MOVING UPPER LEVEL
LOW PRESSURE AREA...HAVE CHANCES OF SHOWERS AND STORMS THROUGH
THE ENTIRE LONG TERM. HIGHS WILL BE GENERALLY ABOVE NORMAL ACROSS
THE CWA IN THE 70S THROUGH THURSDAY THEN COOLING OFF SOME FOR
FRIDAY AND SATURDAY.


&&

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

ONE ROUND OF THUNDERSTORMS HAS CLEARED BOTH KPIR/KMBG...WHILE A
SECOND BATCH OF CONVECTION APPEARS TO BE HEADED FOR KMBG /WITHIN
THE NEXT 3 TO 6 HOURS IF IT HOLDS TOGETHER/. A SEPARATE AREA OF
THUNDERSTORMS IS WORKING UP FROM SOUTHEAST SOUTH DAKOTA...AND
POSES A MORE PROBABLE THREAT OF REACHING...AT LEAST THE KATY
/MAYBE KABR AS WELL/ TERMINAL EARLY THIS MORNING. VCTS AND
VCSH/SHRA ARE IN THE TAFS FOR THIS MORNING. ONCE CONVECTION CLEARS
THE AREA THIS MORNING...DRY CONDITIONS ARE EXPECTED TO ENSUE FOR
THE REMAINDER OF THE TAF VALID PERIOD.

ON SOME COMPONENT OF BREEZY EASTERLY BOUNDARY LAYER FLOW...AMPLE
LOW LEVEL MOISTURE IS AIDING THE FORMATION AND CONTINUANCE OF LOW
STRATUS ACROSS THE CWA. EXPECT SOME FORM OF EITHER IFR OR MVFR
STRATUS TO STICK AROUND AT ALL FOUR TAFS FOR MUCH IF NOT ALL OF
THE TAF VALID PERIOD.


&&

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

$$
UPDATE...DORN
SHORT TERM...SD
LONG TERM...MOHR
AVIATION...DORN

WEATHER.GOV/ABERDEEN