Area Forecast Discussion
Issued by NWS Aberdeen, SD

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000
FXUS63 KABR 270911
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
411 AM CDT WED AUG 27 2014

.SHORT TERM...THROUGH FRIDAY

SURFACE HIGH PRESSURE CONTINUES TO BACK OUT OF THE CWA...AND A
COUPLE OF WEAK SHOWERS/STORMS HAVE DEVELOPED ON THE NORTHERN
FRINGE OF WARM ADVECTION ACROSS FAR SOUTHERN COUNTIES THIS AM.

MAIN THREAT THIS FORECAST PERIOD IS THE POTENTIAL FOR HEAVY
RAIN TONIGHT/THURSDAY...UNFORTUNATELY WITH LOW CONFIDENCE THANKS
TO RATHER STRIKING DIFFERENCES BETWEEN THE NAM AND GFS.

NAM PROVIDES A MUCH BETTER JET SIGNATURE AND STRONGER MID LEVEL
FRONTOGENISIS...ALONG WITH A DEEPER LOW...AND A MORE NORTHERLY
TRACK. THIS PUSHES THE QPF BULLSEYE WELL INTO THE CWA. THE NAM
TREND HAS EXISTED SINCE 18Z AND IS CURRENTLY ENCOMPASSED WITHIN THE
06Z RUN. SREF AND GEM/ECMWF HAVE A SOMEWHAT LESS NORTHERLY EXTREME
BUT THE SREF HAS PROBABILITIES GREATER THEN 2 INCHES FOR THE
SOUTHERN TIER OF THE CWA AND BOTH THE GEM/ECMWF BRING THE
PRECIPITATION BULLSEYE CLOSE ENOUGH TO THE CWA TO BE CONCERNED.
THE GFS IS THE SOUTHERLY OUTLIER.

NAM SUGGEST GENERALLY WEAK CONVECTION WITH MOIST ADIABATIC
PROFILES...AND LESS THEN 500 J/KG CAPE. THERE WILL BE ABOUT 20 TO
30 MICROBARS OF LIFT ALONG AN NARROW EAST WEST AXIS WITH A LOW
NORTHEAST MOVEMENT. SINCE STORMS ARE LIKELY DOMINATED BY WARM
CLOUD PROCESSES WITH SLOW EXPECTED MOTION...ADDED THE MENTION OF
HEAVY RAIN ACROSS FOR SOUTHEAST COUNTIES. AS THIS AREA OF THE CWA
HAS ESCAPED HEAVY RAIN IN THE PAST COUPLED OF DAYS...AND THE
UNCERTAINTY OVER EXACT LOCATIONS FOR STORMS...WILL OPT OUT OF
ANY FLOOD HEADLINES.


.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
MODELS REMAIN RELATIVELY SIMILAR AND MAINTAIN DECENT 24 HOUR
CONTINUITY. POPS CONTINUE TO BE SPRINKLED THROUGHOUT THE EXTENDED
WHILE FLATTER...MORE ZONAL-TYPE...UPPER FLOW PERSISTS. STILL
WATCHING SUNDAY AFTERNOON/EVENING AS A POSSIBLE ROUND OF STRONG
CONVECTION WITH A COLD FROPA AND MODERATELY STRONG MID-LEVEL
SHORTWAVE PROGGED. TEMPERATURES SHOULD BE RUNNING GENERALLY CLOSE
TO NORMAL FOR THIS TIME OF YEAR.



&&

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

VFR MID LEVEL CLOUDS WILL CONTINUE TO STREAM OVER THE REGION
TONIGHT AND WEDNESDAY IN ADVANCE OF AN UPPER LEVEL LOW PRESSURE
TROUGH. TSTORMS ASSOCIATED WITH THE TROUGH MAY CREEP UP INTO
SOUTH CENTRAL SD TONIGHT BUT SHOULD REMAIN SOUTH OF KPIR. BEST
CHANCES OF SEEING TSTORMS NEAR KPIR AND KATY WILL BE AFTER 18Z FOR
KPIR AND AFTER 0Z THURSDAY FOR KATY. HOWEVER TIMING AND NORTHERN
EXTENT OF ANY STORMS IS UNCERTAIN ENOUGH AT THIS TIME TO LEAVE A
MENTION OUT OF THE TAFS.








&&

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

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

WEATHER.GOV/ABERDEEN




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