Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 062316
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
616 PM CDT FRI MAY 6 2016

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 306 PM CDT FRI MAY 6 2016

WEAK SHORT WAVE AND ATTENDANT SURFACE COLD FRONT WILL MOVING
SOUTHWARD ACROSS THE FORECAST AREA TONIGHT. PRECIP CHANCES ARE A
TOUGH CALL WITH THIS SYSTEM. BOTH THE NAM AND GFS HUMIDITY TIME
SECTIONS AND SOUNDINGS SHOW VERY LITTLE IN THE WAY OF LOW LEVEL
MOISTURE BELOW ABOUT 750MB...WITH OBVIOUSLY WELL MIXED CONDITIONS
AHEAD OF THE BOUNDARY THIS AFTERNOON ADDING TO THE DRYNESS. THE
FORCING WITH THE SHORT WAVE IS NOT OVERLY IMPRESSIVE...BUT THIS
EVENING THERE IS A FAIR AMOUNT OF PURE ELEVATED INSTABILITY. THE
WIND SHEAR IS RATHER WEAK HOWEVER...NOTED WITH 30 KNOTS AT 925MB AND
ONLY 5 TO 10 KNOTS AT 700MB. INTERESTINGLY...THE HRRR CONTINUES TO
DEVELOP CONVECTION LATE THIS AFTERNOON AND EARLY EVENING ALONG THE I
90 AND HIGHWAY 14 CORRIDORS. THE HIGHWAY 14 CONVECTION WOULD BE
ASSOCIATED WITH LOW LEVEL CONVERGENCE ALONG THE COLD FRONT. HOWEVER
THE I 90 CONVECTION IS WELL AHEAD OF THE FRONT. AM SKEPTICAL ABOUT
THE I 90 CONVECTION DEVELOPING SO EARLY...AS IT IS LIKELY KEYING OFF
OF THE CONVECTIVE TEMPERATURE. INDEED...THE HRRR IS TRYING TO SHOW
CONVECTION DEVELOPING RIGHT NOW IN SOUTH CENTRAL SD AND THERE IS
NOTHING THERE. IT IS THAT CONVECTION WHICH IT THEN EXTENDS EASTWARD
ALONG I 90. SO FOR NOW ADDED ONLY VERY LOW POPS TO THE I 90 CORRIDOR
VERY LATE THIS AFTERNOON AND EARLY EVENING TO ACCOUNT FOR THE
HRRR SCENARIO...AND KEPT THE HIGHER SCATTERED POPS IN OUR NORTHERN
ZONES CLOSER TO THE ACTUAL FRONT. CHANCE OR SCATTERED POPS SHOULD
THEN DRIFT SOUTHWARD THROUGH THE NIGHT...BUT AGAIN CHANCES ARE
FAIRLY SKITTISH AT ANY GIVEN POINT LOCATION THAT YOU WILL ACTUALLY
GET WET. IN ADDITION...STABILITY INCREASES AFTER MIDNIGHT TO THE
POINT WHERE BY SATURDAY...THERE IS LITTLE IN THE WAY OF INSTABILITY
LEFT IN OUR SOUTHERN ZONES WHERE SMALL POPS LINGER UNDER A MID DECK
OF CLOUDS.

FOR TEMPERATURES...LATEST LOWS ARE LITTLE CHANGED FROM PREVIOUS
RUNS...WITH UPPER 40S IN OUR FAR NORTHERN ZONES...TO NEAR 55 IN
SIOUX CITY AND STORM LAKE IA. HIGHS SATURDAY WILL BE COOLER...
WITH READINGS IN THE UPPER 60S TO AROUND 70.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 306 PM CDT FRI MAY 6 2016

SATURDAY NIGHT INTO SUNDAY WILL SEE LOW PRESSURE ALOFT DEVELOP
ACROSS THE CENTRAL ROCKIES AS HIGH PRESSURE AT THE SURFACE SETTLES
INTO THE NORTHERN PLAINS. THIS SHOULD ALLOW FOR MAINLY DRY
CONDITIONS DURING THIS TIME. THERE WILL BE A CHANCE FOR
SHOWERS CLOSER TO THE MISSOURI RIVER CORRIDOR CLOSER TO THE MID LEVEL
MOISTURE...BUT CHANCES NOT REAL HIGH. EASTERLY FLOW WILL ALLOW
COOLER AIR TO FILTER IN BUT BE OFFSET A BIT BY CLOUD COVER AT NIGHT.
LOWS SHOULD MAINLY BE IN THE 40S...CLOSER TO 40 ALONG HIGHWAY 14 AND
CLOSER TO 50 ALONG THE MISSOURI RIVER. HIGHS ON SUNDAY...WITH THE
THICKER CLOUDS CLOSER TO THE MISSOURI RIVER SHOULD BE CLOSER TO THE
MID 60S...WITH LOWER 70S POSSIBLE CLOSER TO HIGHWAY 14.

SUNDAY NIGHT INTO MONDAY DEEPER MOISTURE AND BETTER SUPPORT FOR
PRECIPITATION WILL SPREAD NORTH SO SUSPECT THAT THIS WILL BE THE
PERIOD OF TIME FOR THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS. AT
THIS TIME NOT ENOUGH SHEAR OR INSTABILITY TO BE CONCERNED ABOUT
SEVERE WEATHER BUT ENOUGH TO CONTINUE A MENTION OF THUNDERSTORMS.
DIURNAL RANGE NOT TOO WIDE WITH LOWS IN THE 50S SUNDAY NIGHT AND
HIGHS IN THE LOWER TO MID 60S ON MONDAY.

IN THE OUTER PERIODS(TUESDAY THROUGH FRIDAY)...DEEP TROUGHING IN THE
MIDDLE OF THE COUNTRY WILL SPELL COOL AND SHOWERY WEATHER THROUGH
THE PERIOD. WHILE OVERALL CONFIDENCE IN THE DEEPER TROUGH IS FAIRLY
HIGH...CONFIDENCE ON THE INDIVIDUAL PIECES OF ENERGY ARE LOWER THUS
THE CHANCES FOR PRECIPITATION WILL NOT BE ALL THAT HIGH. THERE
SHOULD BE A FEW PERIODS OF SHOWERS AND POSSIBLY THUNDERSTORMS DURING
THIS TIME JUST A PROBLEM OF TIMING. FOR NOW WILL LEAN TOWARDS ONLY A
SHOWERS MENTION AND START ADDING IN THE CHANCE FOR THUNDERSTORMS
WHEN CONFIDENCE INCREASES. AS FOR TEMPERATURES NOT TOO MUCH TO TALK
ABOUT...PRETTY MUCH HIGHS IN THE 60S AND LOWS IN THE 40S. OVERALL
NOT A REAL NICE PERIOD OF WEATHER FOR MID MAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 617 PM CDT FRI MAY 6 2016

GENERALLY VFR THROUGH 08/00Z. EXCEPTION WILL BE ISOLATED TO
SCATTERED SHRA/TSRA ALONG AND BEHIND CDFNT MOVING FROM NORTH TO
SOUTH THROUGH 07/15Z. THESE HIGH BASED STORMS MAY PRODUCE VERY
LOCAL AND BRIEF GUSTS TO 35 KNOTS AND VISIBILITIES 3-5SM.

&&

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

$$

SHORT TERM...MJ
LONG TERM...08
AVIATION...



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