Area Forecast Discussion
Issued by NWS Aberdeen, SD

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KABR 281531 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1031 AM CDT SUN SEP 28 2014

.UPDATE...
COLD FRONTAL BOUNDARY PUSHING INTO THE NORTHERN PART OF THE REGION
THIS MORNING WILL SLOWLY PUSH SOUTH INTO THE EVENING. LOW STRATUS
CLOUDS IN BEHIND THIS FRONTAL BOUNDARY WERE ALSO MOVING INTO MBG
REGION THIS MORNING. THESE LOW CLOUDS WILL HAVE A HARD TIME MAKING
IT SOUTH TODAY AS THE SUN HEATS THE EDGES AND THE MIXING LAYER
DEEPENS. WITH THE STRONGEST CAA REMAINING BEHIND THE BOUNDARY
...STILL EXPECT SOME WARM TEMPERATURES FROM PIR...TO MILLER TO WATERTOWN
TODAY WITH HIGHS AROUND 80 DEGREES. BEHIND THE FRONT IN THE
STRATUS CLOUDS...HIGHS WILL ONLY REACH THE LOWER 60S IN WESTERN
CORSON COUNTY. MODELS STILL INDICATE SOME SHOWER/STORM DEVELOPMENT
ALONG THE FRONTAL ZONE SOUTH IN OUR CWA LATER THIS AFTERNOON AND
EVENING. ALREADY HAVE CHANCES IN THE FORECAST.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...THROUGH TUESDAY

COLD SIDE OF INVERTED TROF SINKING SOUTHWARDS THIS AM...HAS PASSED
INTO KMBG AREA ALREADY. WIDESPREAD CLOUD COVER WITHIN THIS AREA OF
COLD ADVECTION EXTENDS ALONG A LINE FROM KHEI TO KBIS TO THE
MN/ND/CANADIAN BORDER AREA. H85 READINGS ON THE SOUTH SIDE OF THE
TROF ARE +15 TO +18C...SO TEMPS AGAIN WILL TOP OUT IN THE 80S. ON
THE NORTH SIDE OF THE FRONT READINGS WILL STRUGGLE THANKS TO COLD
AIR ADVECTION...POOR MIXING...AND EVENTUALLY CLOUD COVER.

MODELS INDICATE THE COOLER/STABLE AIR CONTINUES TO PUSH SOUTH THIS
AFTERNOON...AND WHILE UNDER THE H5 RIDGE...CONVERGENCE AND A
MARGINALLY UNSTABLE ATMOSPHERE COULD LEAD TO WEAK CONVECTION.
ALREADY SEEING AN EXAMPLE OF THIS JUST NORTH OF THE RADAR THIS AM.
ADDITIONALLY...LOW LEVEL SATURATION FROM 3 TO 6KFT ON THE COLD
SIDE OF THE FRONT WILL DRIFT IN HERE MAINLY TONIGHT. EXPECTING
ONLY A FEW LIGHT SPRINKLES WITH THIS STRATUS LAYER.

BEST CHANCES FOR PRECIPITATION WILL START MONDAY EVENING WEST
RIVER AS A NEGATIVELY TILTED TROF LIFTS OUT OF NEBRASKA AND MOVES
ACROSS SOUTH DAKOTA TUESDAY. A NARROW RIBBON OF ELEVATED INSTABILITY
WILL PASS ACROSS THE FORECAST AREA. CONVECTION...IF SURFACE
BASED...COULD BE SEVERE THANKS TO A HIGH SHEAR ENVIRONMENT AND
500-1000 J/KG ML CAPE. A DRY SLOT WILL LIKELY FOLLOW.

.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY

FORECAST FOCUS IS ON DEPARTING LOW PRESSURE SYSTEM TUESDAY
NIGHT...THEN COOLER CONDITIONS FROM MID TO LATE WEEK.

FORECAST CONFIDENCE: MEDIUM

THERE IS GOOD DETERMINISTIC MODEL AGREEMENT INDICATING THE
NEGATIVE TILT UPPER SHORTWAVE WILL BE LIFTING NEWD THROUGH THE
DAKOTAS AT THE START OF THE EXTENDED PERIOD. STILL EXPECTING SOME
LINGERING PRECIPITATION AFTER 00Z WEDNESDAY...ESPECIALLY ACROSS
FAR NRN AND ERN SECTIONS...BEFORE ALL THE PCPN SHIFTS NWD INTO ND
AND MN. DRIER AIR IS THEN EXPECTED TO OVERSPREAD THE FORECAST AREA
ON WEDNESDAY AND WEDNESDAY NIGHT...WITH THE STRONGER FORCING WELL
NORTH AND EAST. AS SUCH...HAVE TRENDED THE WED/WED NIGHT PERIOD
DRIER WITH LESS CLOUD COVER. ADDITIONAL SHORTWAVE/JET ENERGY IS
THEN EXPECTED TO IMPACT THE NORTHERN PLAINS BY LATE IN THE WEEK AS
THE MEAN UPPER TROUGH SLIDES ACROSS THE REGION. DUE TO POOR MODEL
AGREEMENT ON THE TIMING AND LOCATION OF STRONGEST ASCENT AND
SATURATION...RELIED ON THE CONSENSUS GUIDANCE WHICH YIELDED POPS
IN THE 20-30 PCT RANGE ON THURSDAY THROUGH FRIDAY. ANY QPF AMOUNTS
LATE WEEK WOULD BE LIGHT.

AS FOR TEMPERATURES...SEASONAL READINGS IN THE 60S TO LOWER 70S
ARE EXPECTED ON WEDNESDAY /PREDICATED ON LESS CLOUD COVER/ WITH
READINGS FALLING INTO THE 50S AND 60S ON FRIDAY AND SATURDAY AS
COOLER AIR INFILTRATES THE AREA FROM THE NORTH/NORTHWEST.


&&

.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

A COLD FRONT IS EXPECTED TO GRADUALLY SAG SWD ACROSS SD TODAY.
WINDS AHEAD OF THE FRONT WILL FAVOR A SELY DIRECTION...WITH POST
FRONTAL WINDS TURNING N/NE. SATELLITE IMAGERY SHOWS A WIDESPREAD
AREA OF VFR/MVFR STRATUS CLOUDS OVER ND...MOVING SWD. CIGS WILL
LIKELY REMAIN VFR THROUGH MUCH OF THE MORNING...GRADUALLY BECOMING
MVFR FROM NORTH TO SOUTH THIS AFTERNOON. THERE WILL ALSO BE THE
POSSIBILITY OF RAIN SHOWERS ALONG THE FRONT...WITH THE GREATEST
COVERAGE INVOF OF KATY AND KPIR. BY TONIGHT...MORE WIDESPREAD MVFR
AND POSSIBLY IFR CIGS ARE EXPECTED TO DEVELOP. COULD ALSO SEE LIGHT
RAIN SHOWERS OR DRIZZLE DEVELOP WITH RESTRICTIONS TO VSBYS
POSSIBLE. FUTURE SHIFTS WILL NEED TO FINE TUNE TIMING AND
COVERAGE.


&&

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

$$
UPDATE...MOHR
SHORT TERM...CONNELLY
LONG TERM...FOWLE
AVIATION...FOWLE

WEATHER.GOV/ABERDEEN





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.