108
FXUS63 KABR 042010
AFDABR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
310 PM CDT SAT JUL 4 2009
SHORT TERM
TONIGHT THROUGH MONDAY NIGHT
THE SHORT TERM PERIOD STARTS OFF WITH AN UPPER LEVEL TROUGH
EXTENDING FROM CENTRAL CANADA TO THE NORTHEASTERN UNITED
STATES...AND A RIDGE BUILDING WEST OF THE ROCKIES. THE RIDGE WILL
SLOWLY MAKE ITS WAY EASTWARD THROUGH THE PERIOD...REACHING THE
WESTERN PLAINS MONDAY NIGHT. THIS WILL KEEP NORTHWEST FLOW OVER
THE NORTHERN PLAINS...WITH LITTLE IN THE WAY OF UPPER LEVEL ENERGY
EXPECTED TO AFFECT THE REGION. SURFACE HIGH PRESSURE WILL SLIDE
SOUTHWARD AND BECOME SITUATED OVER THE NORTHERN AND CENTRAL PLAINS
TONIGHT AND SUNDAY. A FRONTAL BOUNDARY WILL DROP ACROSS NORTH
DAKOTA AND NORTHERN SOUTH DAKOTA SUNDAY NIGHT...THEN REMAINS
NEARLY STATIONARY OVER SOUTHERN SOUTH DAKOTA THROUGH THE END OF
THE PERIOD. MODELS INDICATE LITTLE IN THE WAY OF INSTABILITY
TONIGHT THROUGH EARLY MONDAY...BUT LIS FALL INTO THE -2 TO -4
RANGE AND CAPES OF 1000-2000 J/KG DEVELOP MONDAY AFTERNOON. THE
MODEL SOLUTIONS BEGIN TO DIVERGE MONDAY NIGHT...WITH THE GFS
BRINGING LOW PRESSURE FURTHER EAST AND DEVELOPING PRECIPITATION
OVER THE EASTERN DAKOTAS AND MINNESOTA...WHILE THE NAM HAS A MORE
WESTERLY SOLUTION...THEREBY KEEPING PRECIPITATION NORTHWEST OF THE
CWA. BIGGEST ISSUES LOOK TO BE WARMING MID LEVEL TEMPERATURES AND
A LACK OF MOISTURE. MODEL TIME SECTIONS SHOWING SOME HIGH LEVEL
MOISTURE...BUT LITTLE IN THE WAY OF LOW TO MID LEVEL MOISTURE. H7
TEMPERATURES LOOK TO BE IN THE +10 TO +12 DEGREE RANGE BY MONDAY
EVENING...RESULTING IN AN INCREASING CAP. THEREFORE...HAVE OPTED AT
THIS TIME TO LEAVE THE ENTIRE SHORT TERM PERIOD DRY.
TEMPERATURES WILL BE RIGHT AROUND NORMAL ON SUNDAY...THEN WILL SEE
DECENT WAA BEGIN TO DEVELOP. H85 TEMPS CLIMB INTO THE UPPER TEENS
TO MID 20S BY MONDAY...WHICH SHOULD ALLOW FOR TEMPERATURES A GOOD
CATEGORY OR SO ABOVE NORMAL.
LONG TERM
TUESDAY THROUGH SATURDAY
TUESDAY AND WEDNESDAY STILL APPEAR TO BE GOOD LOW LEVEL WAA DAYS
OUT AHEAD OF THE NEXT COLD FROPA...WHICH IS CURRENTLY PROGGED TO
SWEEP THROUGH THIS CWA LATE WEDNESDAY NIGHT THROUGH THE DAYTIME
HOURS ON THURSDAY. SO...CONTINUED THE NEAR TO ABOVE NORMAL
TEMPERATURES FOR THOSE TWO DAYS. ALONG WITH WAA...PLENTY OF LOW
LEVEL MOISTURE GETS PUMPED UP INTO THE CWA...WHICH REALLY PUTS A
PREMIUM ON INSTABILITY/CAPE VALUES TUESDAY AND WEDNESDAY /AND ALSO
THURSDAY ACROSS THE FAR EASTERN FORECAST ZONES/. SO...HAVE
INTRODUCED A SMALL POP FOR TUESDAY...MAINLY FOR THE AFTERNOON
TIMEFRAME...AND THEN KEPT SOME POPS MENTION IN THROUGH WEDNESDAY
NIGHT ACROSS MUCH OF THE CWA. ON THURSDAY...POPS ARE RELEGATED TO
THE EASTERN HALF OF ZONES TO ACCOUNT FOR ANY CONVECTION THAT MIGHT
GO UP ALONG OR AHEAD OF THE COLD FROPA IN THE MOISTURE-RICH AIR IN
PLACE. POPS/WX MENTION WERE THEN TURNED OFF FOR THURSDAY NIGHT
THROUGH FRIDAY NIGHT...MAKING THOSE FORECAST PERIODS DRY ONES...WITH
DRY AIR ADVECTION AND SOME LOW LEVEL CAA ENSUING BEHIND THE FROPA
WHILE HIGH PRESSURE IS WORKING THROUGH THE REGION. THURSDAY AND
FRIDAY ALSO BECOME SLIGHTLY COOLER DAYS AS A RESULT...COMPARED TO
TUESDAY AND WEDNESDAY...WITH COOLER LOW LEVEL AIR IN PLACE. BY
SATURDAY /DAY 7/...RETURN FLOW IS AFFECTING THIS CWA WITH ANOTHER
ROUND OF WAA AND MOISTURE ADVECTION. HAVE INTRODUCED A SMALL POP
MENTION FOR SATURDAY FOR THIS REASON.
AVIATION
18Z TAFS FOR KABR...KATY...KPIR AND KMBG TERMINALS
ISOLATED TO WIDELY SCATTERED SHOWERS HAVE POPPED UP ACROSS THE
FORECAST AREA TODAY. SO FAR...THE KATY TERMINAL HAS BEEN THE ONLY
TERMINAL TO BE THREATENED BY A SHOWER OR WEAK THUNDERSTORM. WITHIN
THE NEXT 6 HOURS /ENDING AT 00Z/...THE KMBG AND KATY TERMINALS
APPEAR TO STAND THE BEST CHANCE OF SEEING A SHOWER OVER TERMINAL
AIRSPACE. CLOUDS AND CONVECTION SHOULD WANE EARLY THIS EVENING WITH
THE SETTING OF THE SUN AND LOSS OF NECESSARY DAYTIME HEATING.
ASIDE FROM POOR FLYING CONDITIONS IN AND AROUND SHOWERS OR
THUNDERSTORMS THIS AFTERNOON...EXPECT GOOD VFR FLYING WEATHER TO
PREVAIL ACROSS THE FORECAST AREA OVER THE NEXT 24 HOURS. THERE IS
A LIMITED POTENTIAL FOR SOME PATCHY GROUND FOG DEVELOPMENT LATE
TONIGHT...INTO EARLY SUNDAY MORNING...AS LIGHT AND VARIABLE WINDS
AND A CLEAR SKY ARE EXPECTED TO SET UP TONIGHT AMID AN AREA OF
SURFACE HIGH PRESSURE BUILDING INTO SOUTH DAKOTA. FOR THE TIME
BEING...WILL LIMIT THE IMPACT OF FOG IN THE TAFS TO THIS FORECAST
DISCUSSION AND MONITOR CONDITIONS THROUGH LATE THIS EVENING/EARLY
SUNDAY MORNING FOR ANY POTENTIAL FOG DEVELOPMENT.
ABR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
SHORT TERM...PARKIN
LONG TERM...DORN
AVIATION...DORN
WEATHER.GOV/ABERDEEN
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