Area Forecast Discussion
Issued by NWS Aberdeen, SD

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000
FXUS63 KABR 200001 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
601 PM CST FRI DEC 19 2014

.UPDATE...
SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT

CURRENTLY ON RADAR THERE IS AN AREA OF FLURRIES MOVING ACROSS FAR
NE SD/WEST CENTRAL MN. THIS WILL EXIT BY 00Z.

MAIN CHALLENGE CONTINUES TO BE STRATUS/FOG AND ITS EFFECTS ON
TEMPERATURES. STRATUS CURRENTLY EXTENDS ON A NORTH SOUTH LINE FROM
EDMUNDS COUNTY TO EASTERN HAND COUNTY EASTWARD. 925 MB RH ON
RUC/NAM/GFS INDICATE DRIER AIR WILL PUNCH AT LEAST AS FAR EAST AS
THE JAMES VALLEY BY 6Z AND THEN ACROSS NORTHEAST SD..WITH THE
EXCEPTION OF WATERTOWN..BY 18Z SATURDAY. AS THERE WAS THIS
MORNING..AREAS ON THE CLEAR SIDE OF THE STRATUS LINE WILL STILL
LIKELY SEE SOME FOG IN THE MORNING ESPECIALLY WHERE THERE IS
SNOW ON THE GROUND. THERE WILL BE LITTLE TEMPERATURE VARIATION
WHERE THE STRATUS LINGERS TONIGHT..PERHAPS ONLY A COUPLE OF
DEGREES SPREAD FROM THE HIGHS TODAY. AREAS WEST WILL FALL INTO THE
TEENS TO AROUND 20.

ON SATURDAY THERE WILL BE A BRIEF PUSH OF WEAK WAA IN THE MORNING
BEFORE A SFC TROUGH SWINGS THROUGH. MODELS DIFFER SIGNIFICANTLY
WITH QPF ASSOCIATED WITH THIS FEATURE. DECIDED TO LEAN TOWARD THE
EC/NAM/RUC DRY SIDE AND KEPT OUT ANY MENTION OF PRECIP. THE GFS IS
CONSIDERABLY STRONGER THAN OTHER MODELS WITH A SHORTWAVE WEST OF
THE MISSOURI RIVER..BUT IS THE OUTLIER AT THIS TIME.

SUNDAY WILL CLEAR OUT BRIEFLY BEFORE A LOW PRESSURE SYSTEM TAKES
AIM AT THE NORTHERN PLAINS BY SUNDAY NIGHT. PRECIP ACROSS THE
CWA MAY BEGIN AS A MIX OF RAIN/SNOW/SLEET/FZRA WITH WARMER AIR IN
PLACE WITH AND AHEAD OF THE LOW. BY EARLY MONDAY MORNING ALL
PRECIP SHOULD CHANGE OVER TO SNOW IN CAA.


.LONG TERM...MONDAY THROUGH FRIDAY

MAIN STORY IN THE EXTENDED REVOLVES AROUND THE STORM SYSTEM
DROPPING SOUTHEAST ACROSS THE AREA MONDAY INTO MONDAY NIGHT.
MODELS IN FAIR AGREEMENT ON EVOLUTION OF SYSTEM...BUT STILL MANY
FINER DETAILS TO WORK OUT. 12Z GFS HAS SHIFTED THE QPF AXIS
FURTHER WEST RIGHT OVER THE JAMES VALLEY AND IS MORE BULLISH ON
SNOW AMOUNTS. INTERESTING TO NOTE THAT THE 12Z EC HAS ALSO SHIFTED
WEST TOWARDS THE JAMES VALLEY...A CHANGE FROM ITS PREVIOUS RUNS.
ALTHOUGH...IT IS NOT QUITE AS HIGH WITH QPF...BUT STILL GIVES THE
AREA A FEW INCHES OF SNOW NONETHELESS. STILL DO NOT HAVE HIGH
CONFIDENCE IN HOW THIS WHOLE SYSTEM WILL EVOLVE...ESPECIALLY WHEN
MODELS SEEM TO STRUGGLE WITH LOWS THAT DROP OUT OF THE NORTHERN
ROCKIES/SOUTHERN CANADA THEN INTENSIFY OVER THE UPPER PLAINS AND
BEGIN TO SHIFT EAST OR NORTHEAST. HAVE BEGUN TO RAMP THINGS UP A
BIT BY INCREASING POPS TO LIKELY BOTH MONDAY AND MONDAY NIGHT.
HAVE ALSO INCREASED QPF/SNOW ACCUMS A BIT. SUPERBLEND WINDS SEEMED
RATHER LOW MONDAY INTO TUESDAY GIVEN THE GRADIENT BEHIND THE LOW
PRESSURE SYSTEM. HAVE THEREFORE ALSO INCREASED WIND SPEEDS.

MODELS SUGGESTING WE MAY ALSO BE DEALING WITH A STORM SYSTEM BY
NEXT FRIDAY. OF COURSE THIS IS A WEEK AWAY BUT IT DOES INDICATE
POTENTIAL FOR A RATHER ACTIVE PATTERN NEXT WEEK WITH A COUPLE
SYSTEMS TO DEAL WITH.


&&

.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

LOW CIGS BELOW 1000 FT WILL CONTINUE TO AFFECT KABR AND KATY
THROUGH THE TAF FORECAST PERIOD...ALTHOUGH THE WESTERN EDGE OF IFR
STRATUS IS JUST A FEW MILES WEST OF KABR. BR ALSO EXPECTED AT
THESE TWO SITES THROUGH THE FORECAST PERIOD. VSBY 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 VSBY ABOVE 1SM AND CONTINUE TO MONITOR. IF STRATUS
DOES IN FACT CLEAR OFF AT KABR...WOULD EXPECT TO SEE VISBY TANK
SIGNIFICANTLY...PROBABLY TO VLIFR HEAVY FOG.

FURTHER WEST OVER KMBG AND KPIR...LOW CIGS NOT A FACTOR TONIGHT
OR SATURDAY WITH GOOD VFR TO START OFF THE TAF VALID PERIOD. LATER
TONIGHT THOUGH...FG/BR A GOOD POSSIBILITY ONCE AGAIN...WITH KPIR
POSSIBLY GOING BELOW 1SM VSBY. SEEMS CHANCES FOR FG/BR BETTER AT
KPIR THAN KMBG SO HAVE NOT LOWERED VSBY AS MUCH IN TAF FOR
KMBG...BUT STILL HAVE A MENTION OF BR NONETHELESS.


&&

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

$$
UPDATE...DORN
SHORT TERM...WISE
LONG TERM...TMT
AVIATION...DORN

WEATHER.GOV/ABERDEEN





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