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 181720
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1220 PM CDT MON MAY 18 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 353 AM CDT MON MAY 18 2015

STRONG WINDS WILL VERY GRADUALLY SUBSIDE...AND MAY RESURGE A BIT IN
SOME AREAS THROUGH MIDDAY...BUT SHOULD NOW REMAIN BELOW ADVISORY
LEVELS. CLOUDS WILL SLOWLY DECREASE TO THE NORTHEAST WITH MUCH OF
SOUTHWEST MINNESOTA REMAINING PRETTY CLOUDY INTO THIS EVENING.
PRECIPITATION SHOULD BE ABSENT ONCE A FEW LINGERING AREAS OF
DRIZZLE OR VERY LIGHT SHOWERS MOVES OUT THIS MORNING. VERY COOL
TEMPERATURES ARE STILL EXPECTED TO BRING HIGHS ONLY IN THE MID 40S
NORTHEAST TO THE MID 50S SOUTH.

THE CLEARING TREND WILL CONTINUE TONIGHT WITH SKIES BECOMING MOSTLY
CLEAR EVERYWHERE LATE. HIGH PRESSURE WILL RIDGE INTO THE AREA BUT
SOME BREEZE IS EXPECTED TO CONTINUE...ALBEIT GETTING PRETTY LIGHT
WEST. TEMPERATURES WILL BE DROPPING TO MARGINALLY FREEZING LEVELS
WEST AND PART OF THE NORTH. THE IDEA OF GOING WITH A FREEZE WARNING
BUT NO FROST ADVISORY WAS AN EXCELLENT ONE AND WILL KEEP IT
GOING...EXPANDING THE WARNING INTO MORE OF THE SOUTHWEST. BECAUSE OF
THE LINGERING BREEZE...EXPECT FROST TO BE PATCHY OVER MOST OF THE
AREA WHERE A FREEZE IS NOT REACHED.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 353 AM CDT MON MAY 18 2015

COOL TEMPERATURES STICK AROUND THROUGH MIDWEEK...BUT INCREASING
CLOUDS AND RAIN CHANCES SHOULD PREVENT ANY FROST/FREEZE THREAT FOR
TUESDAY NIGHT. WILL SEE THE GRADUAL INCREASE IN MID CLOUDS BEGIN
DURING THE DAY TUESDAY...BUT WITH DRY EAST-NORTHEAST LOW LEVEL FLOW
AROUND NORTH DAKOTA SURFACE HIGH...WILL TAKE A WHILE FOR PRECIP TO
REACH THE SURFACE. THUS WILL KEEP MOST AREAS DRY THROUGH TUESDAY
AFTERNOON...THEN RAMP UP TO HIGHER POPS AFFECTING MAINLY SOUTHERN
PARTS OF THE FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY MORNING AS
MID LEVEL WAVE SLIDES THROUGH THE CENTRAL PLAINS. FAIRLY STRONG
ISENTROPIC LIFT AHEAD OF THE WAVE...THOUGH DEPTH OF MOISTURE STILL A
BIT IN QUESTION...SO WILL HOLD TO LIKELY RANGE POPS FOR NOW. RAIN
SHOULD WIND DOWN THROUGH WEDNESDAY AFTERNOON AS THE WAVE PASSES BY
AND ISENTROPIC DOWNGLIDE STARTS TO DOMINATE. CLOUDS AND OVERALL COOL
AIR MASS WILL HOLD DAYTIME HIGHS IN THE 50S TUESDAY/WEDNESDAY...WITH
THE COOLEST READINGS IN AREAS WITH THICKEST CLOUDS AND HIGHER RAIN
CHANCES.

ANOTHER PERIOD OF WEAK MID LEVEL RIDGING WILL BRING DRY CONDITIONS
FOR THURSDAY/FRIDAY...WITH TEMPERATURES MODERATING CLOSER TO NORMAL
WITH HIGHS IN THE 60S TO NEAR 70.

THE UPCOMING HOLIDAY WEEKEND BRINGS A FAIR AMOUNT OF UNCERTAINTY.
BOTH GFS/ECMWF IN MODEST AGREEMENT IN THE UPPER LEVELS...SHOWING
ANOTHER MID/UPPER LEVEL TROUGH TRACKING INTO THE PLAINS...WHICH
PRODUCES UNSETTLED WEATHER FOR SATURDAY/SUNDAY. OPERATIONAL GFS
CURRENTLY STRONGER/FARTHER NORTH THAN THE ECMWF...AND ALSO APPEARS
TO HAVE LITTLE SUPPORT FROM MANY OF ITS OWN ENSEMBLE MEMBERS...SO
LOW CONFIDENCE IN THAT SOLUTION. MAIN IMPLICATION LOOKS TO BE IN
CONVECTIVE EXTENT...AS FARTHER NORTH GFS IS WARMER AND MUCH MORE
UNSTABLE THAN THE MORE SOUTHERN SOLUTIONS WHICH HOLD THE LOW LEVEL
BOUNDARY SOUTH OF OUR FORECAST AREA. THUS WILL KEEP POPS CLOSE TO
MODEL BLEND HIGH CHANCE/LIKELY RANGE...BUT THUNDER THREAT MAY BE
MORE ISOLATED TO SCATTERED THAN OVERALL RAIN CHANCES IF THE SOUTHERN
SOLUTION PANS OUT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1217 PM CDT MON MAY 18 2015

MVFR CEILINGS GRADUALLY LIFTING/DISSIPATING FROM WET TO EAST THIS
AFTERNOON...LINGERING LONGEST IN SOUTHWEST MINNESOTA. MODEL
SOUNDINGS HINT TAT THIS STRATUS MAY CONTINUE INTO THE OVERNIGHT
HOURS BUT WITH DRIER AIR WORKING IN AND SUBSIDENCE ACROSS THE AREA
SUSPECT THAT ONCE THE STRATUS DISSIPATES IT WILL BE GONE FOR THE
NIGHT. SO...MVFR THROUGH ABOUT SUNSET OR A LITTLE AFTER THEN VFR.
VERY STRONG NORTHWEST WINDS WILL ALSO DECREASE QUICKLY THIS
EVENING.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...FREEZE WARNING FROM 3 AM TO 8 AM CDT TUESDAY FOR SDZ038>040-050-
     052>060-063-064.

MN...FREEZE WARNING FROM 3 AM TO 8 AM CDT TUESDAY FOR MNZ071-097.

IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...
LONG TERM...JH
AVIATION...08


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