FXUS63 KABR 211958
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
258 PM CDT THU AUG 21 2008

.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
STRONG SYSTEM PER MODELS AND RECENT SATELLITE PIX IS PUNCHING
INTO AND THROUGH THE NORTHERN ROCKIES WITH AN ASSOCIATED 100KT+ JET
MAX. SYNOPTIC SCALE LIFT SHOULD SPREAD OUT ACROSS WESTERN NORTH
DAKOTA THIS EVENING AS LEFT EXIT REGION OF JET MAX ENTERS THE
AREA. MEANWHILE...SURFACE FRONT WILL ALSO BEGIN SURGING EAST AS
PRESSURE RISES INCREASE UNDER CONFLUENT FLOW ALOFT POST JET MAX.
AHEAD OF THE FRONT WINDS WILL REMAIN SOMEWHAT OF AN ISSUE INTO THE
EVENING HOURS. IN THE LAST HOUR SFC WINDS HAVE BEGUN PEGGING
ADVISORY CRITERIA AT MOST ASOS LOCATIONS. WILL WAIT TILL LAST
MINUTE TO DECIDE ON WIND ADVISORY FOR THE EVENING HOURS.
THUNDERSTORM POTENTIAL AHEAD OF THE BOUNDARY DOES NOT LOOK TOO
IMPRESSIVE ACROSS CWA. THERE IS A FAIR AMOUNT OF SURFACE BASED
CAPE ACROSS THE REGION...BUT CONVECTIVE INHIBITION REMAINS QUITE
HIGH UNDER VERY WARM THERMAL RIDGE ALOFT. AND MODELS INDICATE THAT
THE THERMAL RIDGE WILL ONLY INTENSIFY JUST AHEAD OF THE BOUNDARY TNT.
NONETHELESS STRONG LLJ AND SOME SURFACE CONVERGENCE AHEAD OF FRONT
COULD SPARK AN ISOLATED STORM...SO WILL MAINTAIN SLIGHT CHANCE
POPS FOR NORTHERN CWA...WHICH IS CO-LOCATED WITH STRONGEST
SYNOPTIC SCALE LIFT. IN ACCORDANCE WITH THE POP...CONFIDENCE IS
LOW THAT THERE WILL BE ANY MEASURABLE RAIN OVER THE FORECAST AREA
TNT. FRONT BLOWS THROUGH EARLY ON FRIDAY WITH MUCH DRIER AND
SOMEWHAT COOLER AIR FOR THE REST OF THE WEEKEND. MAV GUIDANCE
LOOKED OKAY WITH A FEW TWEAKS...ESPECIALLY TO AFTERNOON
HIGHS...WHICH IS WHERE THAT PARTICULAR GUIDANCE HAS HAD A RECENT
WARM BIAS.

.LONG TERM...SUNDAY THROUGH THURSDAY
MODELS ARE IN A FAIR AGREEMENT THROUGHOUT THE EXTENDED. THE PERIOD
OPENS WITH A WEAK MID/UPPER LEVEL TROF IN THE EASTERN CONUS AND
RIDGE OVER THE ROCKIES. THIS LEAVES THE AREA UNDER NORTHWEST FLOW
ALOFT. AT THE SURFACE...A LARGE AREA OF HIGH PRESSURE VIRTUALLY
DOMINATES THE MIDWEST. THE HIGH SLOWLY MOVES EASTWARD WHICH ALLOWS
FOR RETURN FLOW INTO THE CENTRAL AND NORTHERN PLAINS. HAVE
INTRODUCED SLIGHT POPS ACROSS THE SOUTHWEST PORTION OF THE CWA
SUNDAY NIGHT THROUGH MONDAY NIGHT AS MODELS INDICATE A THETA-E
RIDGE...ALONG WITH ML CAPES ABOVE 1500 J/KG. HOWEVER...AM A BIT
CONCERNED WITH THE AMOUNT OF MOISTURE ADVECTION AS GUIDANCE DEW
POINTS ARE SHOWN IN THE MID TO UPPER 50S. THE MID/UPPER LEVEL
RIDGE BEGINS TO BREAKDOWN TOWARDS THE MIDDLE OF THE WEEK AS AN
TROF PUSHES THROUGH THE ROCKIES. DUE TO MODEL UNCERTAINTY...HAVE
ADJUSTED HPC GUIDANCE WITH THE REGARDS TO A MID/UPPER LEVEL TROF
AND SURFACE COLD FRONT THE IS EXPECTED TO SWING THROUGH THE AREA
BY THE END OF THE WORK WEEK.

&&
.AVIATION...
GUSTY SOUTHERLY WINDS CAN BE EXPECTED AT ALL TERMINALS THROUGH
THIS EVENING. WINDS ARE EXPECTED TO RANGE FROM 20 TO 30 MPH WITH GUSTS
UP TO 35 MPH. WINDS WILL DIMINISH SOME DURING THE OVERNIGHT HOURS. A
COLD FRONT WILL MOVE ACROSS THE STATE FRIDAY MORNING WITH WINDS
SHIFTING TO THE WEST AT KPIR AND KMBG BY 12Z. KABR AND KATY WILL
QUICKLY FOLLOW. WIND WILL BE GUSTY TOMORROW AFTERNOON. KATY MAY
EXPERIENCE MVFR CONDITIONS WITH CIGS AOA 2K FT. OTHERWISE VISBY AND CIGS ARE
EXPECTED TO REMAIN VFR THROUGH THIS EVENING AND INTO TOMORROW.
&&

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

$$
SHORT TERM...TDK
LONG TERM...SD
AVIATION...SD

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