Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 231741
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
1241 PM CDT WED JUL 23 2014

.UPDATE...
UPDATED AVIATION DISCUSSION BELOW.

PRECIPITATION CHANCES HAVE DIMINISHED OVER THE AREA AS HIGH
PRESSURE DROPS SOUTHWARD...THEREFORE HAVE REMOVED POPS FOR THE
REMAINDER OF THE DAY PERIOD. NO OTHER CHANGES MADE TO THE FORECAST
AT THIS TIME.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH FRIDAY
UPPER RIDGE BUILDING TO THE WEST...BUT NOT BEFORE A 70KT JET
STREAK ROUNDS THE TOP. THIS FEATURE IS SUPPORTING WEAK ELEVATED
CONVECTION IN NORTH DAKOTA. SOME OF THIS COULD LEAK INTO THE CWA
DURING THE MORNING HOURS BEFORE DISSIPATING...BUT MOST OF THE AREA
WILL REMAIN DRY. SURFACE HIGH PRESSURE MIGRATES SOUTHEAST
TODAY...THOUGH THERMAL ADVECTION WILL REMAIN NEUTRAL FOR MOST OF
THE AREA SO ANTICIPATING ANOTHER DAY WITH SEASONALLY MILD
TEMPERATURES AND LOW HUMIDITY.

LATE AFTERNOON/EVENING...GUIDANCE BEGINS TO BRING A PLUME OF H5
MOISTURE AROUND THE UPPER HIGH CENTERED SOUTH OF THE REGION. H7
TEMPERATURES ALSO BEGIN TO WARM RATHER DRASTICALLY...OVER 2
STANDARD DEVIATIONS ABOVE CLIMO. GFS H7 TEMPS ACTUALLY PEAK
NEAR +18C WEST RIVER. THE DEVELOPMENT OF ELEVATED CONVECTION
SHOULD BE ALONG A 40-50KT LOW LEVEL JET THAT PARALLELS THE
MISSOURI OVERNIGHT. BOTH THE GFS/NAM SUGGEST RATHER MUNDANE HIGH
BASED CIGS WITH LIMITED MID LEVEL INSTABILITY...HOWEVER THEY ARE
SUGGESTING WITHIN SOUNDINGS THAT A LIMITED SEVERE THREAT IS
POSSIBLE IF WARM ADVECTION IS A TAD STRONGER THEN CURRENTLY
MODELED AND THE NAMS/GFS NARROW RIBBON OF HIGHER DEWPOINTS AIR
AROUND 6KFT MIGRATES INTO THE CWA. THE BEST FOCUS FOR CONVECTION
WILL SHIFT EAST THURSDAY NIGHT AS A 50KT LOW LEVEL JET SETS UP
POINTED TOWARDS WESTERN MINNESOTA. FLOW ALOFT BECOMES DIFLUENT
FOR FRIDAY. PROFILES IN EASTERN COUNTIES INDICATE SOME INSTABILITY
WITHIN THE POST FRONTAL AIRMASS SO THE THREAT FOR CONVECTION
REMAINS INTO EARLY AFTERNOON.



.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
ALMOST ZONAL WNW FLOW ALOFT AND A LARGE UPPER LOW CIRCULATION
TRACKING ACROSS SOUTHERN CANADA INTO THE GREAT LAKES REGION/UPPER
MS RIVER VALLEY REGION HEADLINES THE FIRST COUPLE OF DAYS OF THE
EXTENDED. THEN...FLOW ALOFT AMPLIFIES CONSIDERABLY BECOMING
INCREASINGLY MERIDIONAL NW FLOW. SURFACE HIGH PRESSURE DROPPING
OUT OF CANADA WILL DOMINATE THE WEATHER MAP OVER THESE PARTS FOR
JUST ABOUT THE ENTIRE FORECAST PERIOD.

LOW LEVEL CAA HAS COMMENCED BY FRIDAY NIGHT...AND PRETTY MUCH
DOESN`T STOP UNTIL MONDAY MORNING. SATURDAY SHOULD BE THE WARMEST
DAY OF THE EXTENDED. BUT THE WHOLE PERIOD COULD BE CHARACTERIZED
AS BELOW CLIMO NORMAL FOR TEMPERATURES.

AS THE PREVIOUS SHIFT INDICATED...SORTA TOUGH TO IDENTIFY ANY
PARTICULAR PERIOD AS FAVORABLE FOR PRECIPITATION. MOST OF THE
PERIOD SHOULD BE DRY. STRONG UPPER JET WORKING THROUGH ON THE
SOUTHERN FLANK OF SAID UPPER LOW CIRCULATION. PERHAPS THERE IS A
LOW PROBABILITY OF PRECIP FRIDAY NIGHT/SATURDAY WITH THAT FEATURE.
OTHERWISE..."COLD AIR-INSTABILITY" SHOWERS COULD GET GOING ACROSS
THE FAR EASTERN ZONES WHILE THE UPPER LOW IS PASSING BY TO THE
NORTHEAST AND EAST THROUGH SUNDAY AFTERNOON.





&&

.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

VFR CONDITIONS SHOULD PERSIST THROUGH THE VALID TAF FORECAST
PERIOD. BREEZY CONDITIONS WILL DEVELOP AT ALL TERMINAL LOCATIONS
AFTER 11Z IN RESPONSE TO A DEEPENING LOW PRESSURE SYSTEM TO THE
WEST. AN UPPER LEVEL IMPULSE WILL MOVE SOUTHEAST OUT OF MONTANA
INTO SOUTH DAKOTA AFT 06Z. ATTM JUST INCREASED AMOUNT OF MID CLOUD
AND WITHHELD PCPN MENTION UNTIL TIMING/LOCATION/AMOUNT OF LOW
LEVEL MOISTURE BECOMES BETTER DEFINED IN THE MODELS.


&&

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

$$
UPDATE...PARKIN
SHORT TERM...CONNELLY
LONG TERM...DORN
AVIATION...HINTZ

WEATHER.GOV/ABERDEEN




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