Area Forecast Discussion
Issued by NWS Sioux Falls, 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 KFSD 281722
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1222 PM CDT THU MAY 28 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CDT THU MAY 28 2015

COMPLEX FORECAST IN THE SHORT TERM WITH SEVERAL PLAYERS COMING INTO
PLAY LEADING TO A POTENTIAL ACTIVE FORECAST PERIOD. MESSY
FORECAST TODAY BUT IN- GENERAL...POPS CENTERED AROUND SHORT WAVE
LIFTING NORTHEAST ACROSS NORTHWEST IOWA LATE THIS AFTERNOON...AND
THE FRONT APPROACHING FROM THE WEST. WITH STORMS AHEAD OF THE
FRONT...COULD SEE AN OUTSIDE CHANCE OF A STRONG WIND GUST OR TWO
WITH FAIR AMOUNT OF DRY AIR ALOFT
INITIALLY...HOWEVER...INSTABILITY IS QUITE LIMITED AND IS VERY
THIN LIMITING SEVERE POTENTIAL.

FOR TONIGHT...STRONG COLD FRONT MOVES ACROSS THE AREA AND HAVE
CONCENTRATED LIKELY POPS ALONG THE FRONT.  LOWS WILL BE MILD AHEAD
OF THE FRONT...BUT IN THE 50S BEHIND THE FRONT AS COLD PUSH OF AIR
STARTS TO WORK IN FROM THE NORTH.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM CDT THU MAY 28 2015

ON FRIDAY...THE GFS CONTINUES TO BE THE MOST AGGRESSIVE MODEL IN
BRINGING THROUGH A SHORT WAVE FRIDAY MORNING ASSOCIATED WITH THE
NORTHERN JET STREAM. THIS WAVE AT 12Z FRIDAY AT 500MB EXTENDS FROM
NORTHEAST SD TO NORTHWEST MN ON THE GFS...WHICH IS THE POSITION OF
THE ECMWF AT 18Z FRIDAY. THE NAM AND GEM GLOBAL ARE CLOSER TO THE
ECMWF POSITION AT 18Z FRIDAY...ALBEIT THE NAM LOOKS LIKE A BIT OF A
SLOW OUTLIER. BEHIND THIS WAVE IS A SHORT WAVE ASSOCIATED WITH THE
SOUTHERN JET WHICH EXTENDS ACROSS THE NEB PANHANDLE AND EASTERN CO
AT 18Z FRIDAY...MOVING INTO THE CENTRAL PLAINS FRIDAY AFTERNOON AND
EVENING. BELIEVE AT THIS TIME THE ECMWF AND GEM GLOBAL SOLUTIONS ARE
LIKELY THE MOST CORRECT AND CERTAINLY A COMPROMISE BETWEEN THE GFS
AND NAM...ALTHOUGH AGAIN STRESSING THAT THE NAM IS NOT A LOT SLOWER
THAN THE ECMWF AND GEM GLOBAL. THEREFORE FOR PRECIPITATION TRENDS
AND ASSOCIATED SURFACE TO 850MB WIND SHIFT TIMING...PRIMARILY
FOLLOWED THE GEM GLOBAL AND ECMWF. LIKELY POPS ARE WARRANTED FRIDAY
MORNING ACROSS MOST OF OUR FORECAST AREA MINUS OUR NORTHWEST
ZONES...ALTHOUGH THE HANG BACK OF THE ECMWF 6 HOUR QPF FRIDAY
MORNING IN OUR NORTHERN ZONES ASSOCIATED WITH THE NORTHERN STREAM
SHORT WAVE IS RATHER DISTURBING. THEREFORE THIS WILL HAVE TO BE
WATCHED FOR A POSSIBLE RAISING OF THE STRONG CHANCE POPS AROUND
HURON TO LIKELY POPS IN FUTURE FORECASTS. ON FRIDAY AFTERNOON... THE
LIKELY POPS WILL SHOVE SOUTHWARD INTO OUR SOUTHERN ZONES. THAT SAID
RAIN AMOUNTS WILL PROBABLY NOT BE VERY HIGH AT ALL BY FRIDAY
AFTERNOON. LOOKS LIKE THE 850MB FRONT IS PUSHING THROUGH WAY TOO
FAST TO WORRY ABOUT ANY SEVERE POTENTIAL ON FRIDAY...BUT IT WILL BE
QUITE WINDY BEHIND THE FRONTAL PASSAGE. IN FACT LOCATIONS FROM
AROUND MITCHELL...TO BROOKINGS AND THE NORTHERN SECTIONS OF
SOUTHWEST MN MAY PUSH WIND ADVISORY CRITERIA AS THEY ARE IN THAT
SWEET SPOT OF STRONGEST GRADIENT...STRONGEST WINDS ALOFT AND TIME OF
DAY ALL COMING TOGETHER.

SMALL RAIN CHANCES WILL MOVE SOUTHWARD ACROSS NORTHWEST IA DURING
FRIDAY EVENING. AFTER THAT AND THROUGH THE WEEKEND...NOT A LOT GOING
ON FOR A CHANGE. IT WILL STILL BE QUITE BREEZY FRIDAY NIGHT FOR MANY
LOCATIONS...HOWEVER THE COLD AIR ADVECTION PUSH IS ABNORMALLY STRONG
FOR THIS TIME OF YEAR. SO LOOKING AT LOWS FROM 40 AROUND HURON TO 50
AT STORM LAKE. QUITE CHILLY FOR THIS TIME OF YEAR. THIS WILL BE
FOLLOWED BY HIGHS ONLY IN THE 60S ON SATURDAY WITH A WELL MIXED DAY
ALLOWING TEMPERATURES TO MIX TO ABOUT 800MB. SUNDAYS HIGHS WILL BE 5
TO 10 DEGREES WARMER THAN SATURDAYS.

IN THE EXTENDED...A STRONG SOUTHERLY FLOW OF AIR WILL SETUP SHOP ON
MONDAY AND TUESDAY...LINGERING ACROSS OUR EASTERN ZONES ON
WEDNESDAY. THEREFORE INCREASED THE SUPERBLEND WINDS AS THEY WERE TOO
LIGHT. THIS WILL ALLOW FOR A WARMUP MORE COINCIDENT WITH EARLY
SUMMER/LATE SPRING TYPE HIGHS...WITH TUESDAY LOOKING THE WARMEST AT
80 TO 85 DEGREES. RIGHT NOW...RAINFALL CHANCES LOOK SKITTISH UNTIL
POSSIBLY WEDNESDAY AND WEDNESDAY NIGHT...WHEN BOTH THE ECMWF AND GFS
SHOW A SERIES OF SHORT WAVES MOVING THROUGH AN UPPER TROUGH.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1214 PM CDT THU MAY 28 2015

KHON OBSERVATION IS OUT...BUT IS STILL REPORTING ALTIMETER
READING. WITH LIMITED OBSERVATIONS...AMENDMENT(S) ARE NOT
SCHEDULED UNTIL OBSERVATION RETURNS.

GUSTY SOUTHERLY WINDS WILL DIMINISH EARLY THIS EVENING...WITH
THUNDERSTORMS DEVELOPING THROUGH THE WEST IN THE LATE EVENING AS A
COLD FRONT PUSHES INTO THE AREA. THUNDERSTORM CHANCES SHOULD HOLD
OFF AT KFSD AND KSUX UNTIL VERY LATE TONIGHT OR EARLY FRIDAY
MORNING...THOUGH CONFIDENCE IN EXACT TIMING REMAINS FAIRLY LOW.
WINDS WILL GRADUALLY TRANSITION TO NORTHERLY ON FRIDAY AS THE
FRONT MOVES ACROSS THE AREA.

&&

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

$$

SHORT TERM...
LONG TERM...MJ
AVIATION...JM



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