Area Forecast Discussion
Issued by NWS Aberdeen, SD

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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 201723 AAC
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1123 AM CST SAT DEC 20 2014

.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.

BEEN MAKING SEVERAL UPDATES TO GRIDS THIS MORNING...MAINLY
CONCERNING FOG AND CLOUDS. DENSE FOG HAS SETTLED INTO THE JAMES
VALLEY WITH VSBY EARLIER DOWN TO 1/4SM AT ABR AND WEB CAMS
ELSEWHERE ACROSS BROWN/SPINK COUNTIES REVEALING DENSE FOG AS WELL.
GIVEN TIME OF MORNING AND EXPECTED SLOW IMPROVEMENTS OVER THE NEXT
HOUR OR SO...HAVE OPTED TO JUST GO WITH AN SPS TO HIGHLIGHT DENSE
FOG WITH SLOW IMPROVEMENTS BY NOON. VSBY CURRENTLY AT ABR IS
BOUNCING AROUND BETWEEN 1/2SM AND 3/4SM. SUMMIT WEB CAMS SHOWING
DENSE FOG AS WELL...WHICH IS EXPECTED FOR THIS AREA. OTHER WEB
CAMS ACROSS THE EAST REVEALING MAINLY LIGHT FOG. HAVE EXTENDED
PATCHY/AREAS OF FOG WORDING THROUGH THE DAY...KEEPING THE WORSE
CONDITIONS IN THE JAMES VALLEY. OTHERWISE...WATCHING A WEAK UPPER
WAVE SLIDING EAST ACROSS THE DAKOTAS TODAY. THERE ARE SOME WEAK
ECHOES MOVING ACROSS THE WESTERN/CENTRAL DAKOTAS...BUT HAVE NOT
NOTICED ANY OBS CARRYING PRECIP AS OF YET. WILL CONTINUE WITH THE
LOW POPS THROUGH THE DAY AS EVERYTHING SLIDES ACROSS MAINLY THE
NORTHERN CWA. GIVEN THERMAL PROFILES...FREEZING RAIN AND SLEET ARE
POSSIBLE...BUT WITH ONLY VERY LIGHT IF ANY ACCUMS. THEREFORE DO
NOT EXPECT MUCH IN THE WAY OF MEANINGFUL IMPACTS TODAY.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH MONDAY
STRATUS STUCK ACROSS THE EAST YET AGAIN THIS MORNING. TO THE
WEST...MIGHT GET SOME DAYTIME HEATING BEFORE THE NEXT WEAK WAVE.
H925 TEMPS WARM TO BETWEEN -1 AND +4C...THOUGH ITS UNCERTAIN
WHETHER THIS WILL BE REALIZED AT THE SURFACE WITHOUT MIXING. A
NARROW RIBBON OF MID LEVEL CLOUDS/VERY LIGHT QPF WILL RESULT FROM
THE WARM ADVECTION PUSH. THERMAL PROFILE SUGGESTS PTYPE AS
RAIN/FREEZING RAIN...DEPENDING ON SURFACE TEMPERATURES WHICH ARE
AROUND FREEZING. MODEL QPF IS NEGLIGIBLE...SO ONLY SPOTTY IMPACTS
TO TRAVEL EXPECTED.

FOCUS SHIFTS TO SUNDAY NIGHT/MONDAY. CONFIDENCE IS VERY LOW FOR
IMPACTS TO THE REGION...THANKS TO THE VARIETY OF MODEL SOLUTIONS
AND A TRACK GENERALLY FAVORING LOWER END QPF. WITH MILD MID
LEVEL TEMPERATURES IN PLACE...A RAIN/FREEZING RAIN PTYPE IS THE
MOST LIKELY OUTCOME AS THE SYSTEM MOVES ACROSS THE CWA DURING THE
OVERNIGHT HOURS AND SURFACE TEMPERATURES RUN A FEW DEGREES EITHER
SIDE OF FREEZING. GENERALLY LIGHT QPF EARLY MONDAY MORNING GIVEN
WARM ADVECTION/ISENTROPIC UPGLIDE AS THE MAIN SOURCE OF
LIFT...BUT IF THE TIMING COINCIDES WITH THE AM COMMUTE/TRAVEL AND
SCHOOL...THIS COULD POTENTIALLY HAVE A GREATER IMPACT.

COLD ADVECTION WILL RESULT IN A CHANGE OVER TO SNOW ON MONDAY. AS
THE SYSTEM DEEPENS OVER MINNESOTA...WRAP AROUND/TROWAL PRECIP MAY
EXTEND BACK INTO THE CWA FOR ACCUMULATING SNOW...THOUGH GUIDANCE
IS NOT UNANIMOUS IN THIS OUTCOME. THE GRADIENT DOES INCREASE
HOWEVER...SO ANTICIPATE GUSTY WINDS FOR THE MISSOURI VALLEY WEST.


.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
THERE IS STILL A LOT OF UNCERTAINTY IN THE LONG TERM FORECAST.
THE PERIOD STARTS OF WITH AN UPPER TROF/LOW OVER THE NORTHERN
PLAINS...AND PERHAPS EVEN SOME TROWAL INDUCED LIGHT SNOW OVER THE
EASTERN CWA. HOWEVER...THAT TROF GETS SHUNTED EAST AS MORE ENERGY
MOVES SOUTHEAST ACROSS THE ROCKIES. THIS ENERGY IS HANDLED
SOMEWHAT DIFFERENTLY BY THE MODELS...BUT THE RESULT IS A BAND OF
WINTRY PCPN SOMEWHERE OVER THE CENTRAL/NORTHERN PLAINS LATE IN THE
WEEK. FORECAST CONFIDENCE IN THE LATTER PART OF THE PERIOD IS LOW
BASED ON THE VARYING MODEL SOLUTIONS. TEMPERATURES FOR NOW LOOK TO
BE RIGHT AROUND NORMAL FOR MOST OF THE PERIOD.


&&

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

IFR CIGS WILL REMAIN FIRMLY IN PLACE ACROSS THE EASTERN HALF OF
THE CWA THROUGH THE TAF PERIOD. UNDER THE LOW CLOUDS...VSBYS WILL
GENERALLY BE MVFR IN FOG THIS AFTERNOON...BUT THERE WILL LIKELY BE
PERIODS OF IFR VSBYS AGAIN OVERNIGHT AND INTO EARLY SUNDAY
MORNING...AFFECTING KABR AND KATY. VFR CONDITIONS WILL PREVAIL
ACROSS THE WESTERN HALF OF THE CWA WITH JUST SOME HIGH CLOUDS
STREAMING OVERHEAD.


&&

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

$$
UPDATE...TMT
SHORT TERM...CONNELLY
LONG TERM...TDK
AVIATION...PARKIN

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.