Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 270825
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
325 AM CDT MON OCT 27 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CDT MON OCT 27 2014

LIGHT RAIN DEVELOPING AND MOVING EAST TO NORTHEAST. THE MAIN BAND OF
RAIN IS CURRENTLY EXTENDING FROM A SMALL PORTION OF SOUTH CENTRAL
SD...BACK INTO THE NEB PANHANDLE. IT IS HIGH BASED...WITH THE
CEILINGS IN THOSE AREAS AROUND 9000 TO 12000 FEET. SYNOPTICALLY...
THE UPPER WAVE IS EXTENDING ACROSS THE WESTERN PLAINS...AND WILL
MOVE EASTWARD TODAY AND TONIGHT. BY TONIGHT...THE WAVE WILL BEGIN TO
CLOSE OFF SOME AS IT BECOMES CENTERED OVER MINNESOTA.

THE RAIN CURRENTLY HAS DEVELOPED RIGHT ALONG THE 600MB FRONTOGENESIS
AXIS ON THE RAP13. SO THE 700-600MB FRONTOGENETIC LAYER WAS FOLLOWED
TODAY OFF OF THE RAP13 FOR POPS. THE UPPER QG FORCING CONTINUES TO
BE RATHER WEAK AND DISORGANIZED AS WELL AS THE JET STRUCTURE OF THE
WAVE. BUT THE FRONTOGENESIS IS PRETTY STRONG IN THE MID LEVELS. THE
NAM IS A NORTHERN AND WESTERN OUTLIER CONCERNING THE MID LEVEL
FRONTOGENESIS...AND THUS LIKELY HAS ITS RAIN OUTPUT CORRESPONDINGLY
TO FAR TO THE NORTH AND WEST. THE RAP13 AND GFS40 ARE MUCH CLOSER IN
AGREEMENT...ALTHOUGH THE GFS40 QPF MAXIMUM IS DISPLACED TOO FAR TO
THE EAST FROM ITS MAXIMUM MID LEVEL FRONTOGENESIS. FOLLOWING THE
AFOREMENTIONED FRONTOGENESIS...THE BEST OUTPUT APPEARS TO BE THE GEM
REGIONAL...AS WELL AS THE NMM AND ARW FIELDS...AND EVEN THE 4KM NAM
IS MUCH BETTER THAN THE COURSER RESOLUTION NAM. HAVE HIGH POPS FOR
LOW QPF...IN THE LIKELY CATEGORY OR HIGHER...EXTENDING FROM OUR
SOUTH CENTRAL SD ZONES...NORTHEASTWARD INTO THE EASTERN SECTIONS OF
EAST CENTRAL SD AND THE NORTHERN PART OF SOUTHWEST MN. SIOUX FALLS
ITSELF LOOKS LIKE IT IS ON THE EASTERN EDGE OF THE LIKELY POPS...
WITH RAIN CHANCES TAILING OFF RAPIDLY TO THE SOUTH AND SOUTHEAST
FROM THERE. NORTHWEST IA DOES NOT EXHIBIT ANY KIND OF A DEEP
MOISTURE PROFILE...AND THE MID LEVEL FRONTOGENESIS IS VERY WEAK IN
THAT AREA. ALL OF THIS WILL IMPACT TEMPERATURES...WITH THE BIAS
CORRECTED RAW AND ECMWF VALUES LOOKING THE BEST SO FAR. MUCH OF
NORTHWEST IA SHOULD GET INTO THE MID 60S...WITH A STRIPE OF MID 50S
AROUND BROOKINGS. AS THE WINDS BECOME NORTHWESTERLY...THERE WILL
LIKELY BE A BRIEF PERIOD OF SOME FAIRLY BURLY WINDS OF 20 TO 30 MPH
TRANSLATING WEST TO EAST THROUGH THE DAY. MINIMUM HUMIDITY VALUES
LOOK WAY TOO HIGH FOR ANY SORT OF RED FLAG WARNING CONCERNS WHERE
THE WINDS ARE THE STRONGEST THROUGHOUT THE EASTERN HALF OF OUR AREA.

TONIGHT...THE MAIN CHALLENGE IS TIMING STRATUS SOUTHWARD. THE MODELS
CONTINUE TO SHOW IT...AND CURRENTLY THERE IS A LOT OF IT IN SOUTH
CENTRAL CANADA AND FAR NORTHERN MT. AT THIS TIME...THE LOW CLOUDS
WILL LIKELY REMAIN NORTH OF THE MO RIVER VALLEY THROUGH LATE NIGHT.
THERE WILL BE ENOUGH BREEZE AT ANY RATE TO KEEP LOWS ABOVE FREEZING.


.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 322 AM CDT MON OCT 27 2014

UPPER LOW WILL CONTINUE TO PUSH EAST OUT OF THE NORTHERN PLAINS ON
TUESDAY. EXPECT COLDER AIR AND WINDY CONDITIONS BEHIND THIS WAVE.
HIGHS TUESDAY WILL PROBABLY BE THE COOLEST WE HAVE SEEN SINCE THE
BEGINNING OF THE MONTH...WITH UPPER 40S TO LOW 50S COMMON. COMBINE
THAT WITH A NORTHWESTERLY WIND GUSTING 25 TO 35 MPH...AND ABUNDANT
STRATOCU...ESPECIALLY ACROSS THE NORTHEAST HALF OF THE AREA...AND
TUESDAY WILL NOT BE THE NICEST OF DAYS. COULD EVEN SEE AN ISOLATED
SHOWER OR TWO NEAR THE BROOKINGS TO MARSHALL AREA. RIDGE OF HIGH
PRESSURE SETTLES OVERHEAD TUESDAY NIGHT...WHICH SHOULD ALLOW FOR
WINDS TO BECOME LIGHT. COMBINE THAT WITH CLEAR SKIES AND IT SHOULD
BE A COLD NIGHT. THUS LOWERED LOWS SOME INTO THE MID TO UPPER 20S
FOR MOST OF THE AREA...ALTHOUGH WOULD NOT BE SURPRISED IF WE EVEN END
UP A BIT COLDER.

BEGIN TO SEE A SLOW WARMING TREND BY WEDNESDAY WITH HIGHS EXPECTED
TO MAINLY BE IN THE 50S. DOES LOOK LIKE WE WILL SEE A WAVE TRAVERSE
THE REGION IN THE QUICK NORTHWEST FLOW ALOFT. FOR NOW JUST THINK WE
WILL SEE INCREASING CLOUDS WEDNESDAY AFTERNOON...AS LOOKS TOO DRY
FOR ANY SHOWERS TO REACH THE GROUND. WE DO COOL SOME BEHIND THIS
WAVE...BUT WITH GOOD MIXING ON THURSDAY...HIGHS SHOULD STILL MAKE IT
INTO THE 50S AGAIN. THURSDAY NIGHT COULD END UP BEING ANOTHER COLD
ONE GIVEN THE POSITION OF THE RIDGE AXIS NEARBY. THUS TRENDED LOWS
DOWN A TAD...WITH 20S AND 30S LIKELY. DESPITE WARM AIR ADVECTION
ALOFT...THE HIGH MOVING OFF TO THE EAST AND POSITION OF THE UPPER
RIDGE LIKELY WILL RESULT IN POOR MIXING AND COOLER HIGHS ON FRIDAY.
SO MID 40S TO LOW 50S LOOK MOST PROBABLE AT THIS TIME.

UPPER RIDGE SHOULD BE DIRECTLY OVERHEAD ON SATURDAY...WITH UPPER
TROUGHS ON BOTH THE EASTERN AND WESTERN COASTS. WITH THE SURFACE
GRADIENT INCREASING...WINDS SHOULD END UP QUITE BLUSTERY. COULD VERY
WELL SEE SOUTHERLY WINDS GUSTING 25 TO 35 MPH. WITH CONTINUED WARM
AIR ADVECTION...SHOULD SEE HIGHS BACK INTO THE 50S. MODELS DIVERGE
ON THE HANDLING OF THE WEST COAST TROUGH AS IT MOVES EAST...SO
FORECAST CONFIDENCE DECREASES BEYOND SATURDAY. AT THIS TIME LOOKS
LIKE SUNDAY SHOULD SEE MILD TEMPERATURES IN THE 50S AND
60S...WITH RAIN CHANCES UNCERTAIN. WITH THE TROUGH MOVING
ACROSS...CAN NOT RULE OUT A SHOWER THREAT AT SOME POINT LATER SUNDAY
OR SUNDAY NIGHT.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1046 PM CDT SUN OCT 26 2014

VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE PERIOD. SURFACE
TROUGH IS EXPECTED TO SHIFT THROUGH THE AREA OVERNIGHT WITH
SHORTWAVE LIFTING NORTHEAST ACORSS THE AREA DURING THE DAY ON
MONDAY. COULD SEE SOME LIGHT RAIN WITH THE SHORT WAVE...BUT SHOULD
BE RELATIVELY HIGH BASED. BEST CHANCES FOR RAIN WILL BE IN KFSD
OUT OF THREE TAF SITES...BUT SHOULD REMAIN FAIRLY LIGHT. NORTHWEST
WINDS SHOULD PREVAIL THROUGHOUT THE DAY ON MONDAY. NAM SUGGESTS
BREEZIER CONDITIONS THAT WHAT IS FORECAST IN CURRENT
TAFS...ESPECIALLY IN KSUX.


&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...MJ
LONG TERM...CHENARD
AVIATION...



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