Area Forecast Discussion
Issued by NWS Aberdeen, SD

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000
FXUS63 KABR 200947
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
347 AM CST SAT DEC 20 2014

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

IFR CIGS WILL CONTINUE TO AFFECT KABR AND KATY THROUGH THE TAF
FORECAST PERIOD. BR ALSO EXPECTED AT THESE TWO SITES THROUGH THE
FORECAST PERIOD. VISBY EXPECTED TO BE GENERALLY 2SM TO 6SM THROUGH
THE NIGHT...ALTHOUGH THERE IS SOME UNCERTAINTY AS TO WHETHER OR
NOT VISBY WILL FALL BELOW 1SM. FOR NOW WILL KEEP VISBY ABOVE 1SM
AND CONTINUE TO MONITOR.

FURTHER WEST OVER KMBG AND KPIR...LOW CIGS NOT A FACTOR TONIGHT
OR SATURDAY. BUT HAVE ALREADY SEEN VISBY TANK ONCE INTO IFR RANGE
IN FOG AT KPIR...AND FULLY EXPECT IT TO HAPPEN AGAIN BEFORE
SUNRISE. SEEMS CHANCES FOR FG/BR BETTER AT KPIR THAN KMBG SO HAVE
NOT LOWERED VISBY AS MUCH IN TAF FOR KMBG AND ONLY TEMPO`D SOME IFR
CIGS FOR A FEW HOURS THROUGH SUNRISE.



&&

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

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

WEATHER.GOV/ABERDEEN




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