Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 301728 AAC
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1228 PM CDT THU APR 30 2015

.UPDATE...
ISSUED AT 1225 PM CDT THU APR 30 2015

SEE UPDATED AVIATION DISCUSSION BELOW.


UPDATE ISSUED AT 1039 AM CDT THU APR 30 2015

STARTED RED FLAG EARLY AS TEMPERATURES HAVE ALREADY JUMPED INTO
THE 60S WITH RH VALUES DOWN IN THE 20S. WINDS HAVE PEAKED AT
KMBG/KABR AROUND 30MPH AS WELL.

FOCUS SHIFTS TO AFTERNOON CONVECTION. HRRR INDICATES HIGH/SFC
BASED CONVECTION DEVELOPING BETWEEN KMBG/KABR THIS
AFTERNOON...WITH BASES ABOVE 0C...SO POTENTIALLY A DRY MICROBURST
ENVIRONMENT. NAM SOUNDINGS ARE A TAD MORE HUMID...BUT CIGS WILL
LIKELY STILL BE ABOVE 7KFT AND HAVE TO OVERCOME A VERY DRY
SUBCLOUD LAYER FOR PRECIPITATION TO REACH THE SURFACE. AS FOR
TIMING...THE 12Z NAM IS STILL RATHER CONSISTENT...IN LINE WITH
FORECAST AND PREVIOUS NAM/GFS GUIDANCE. THE HRRR IS MUCH FARTHER
EAST...SO AT THIS POINT WILL KEEP CURRENT PROGRESSION OF POPS
ACROSS THE CWA.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY AFTERNOON)
ISSUED AT 347 AM CDT THU APR 30 2015

FIRST ITEM OF DISCUSSION WILL BE THE VERY HIGH FIRE DANGER
DEVELOPING ACROSS THE AREA THIS AFTERNOON. FORECAST RH VALUES ARE
STILL EXPECTED TO RANGE FROM THE UPPER TEENS TO LOW 20S EAST OF
THE MISSOURI RIVER. SOUTH WINDS WILL ALSO INCREASE THIS AFTERNOON
AS THE PRESSURE GRADIENT TIGHTENS AHEAD OF AN APPROACHING COLD
FRONT. SHOULD BE ABLE TO SEE SOME WIND GUSTS MEET OR EXCEED 25 MPH
ACROSS NORTH CENTRAL INTO NORTHEAST SD. PREVIOUS SHIFT HAD ALREADY
ISSUED A RED FLAG WARNING FOR FIRE ZONES 269 AND 271. BASED ON
CURRENT FORECAST RH AND WIND GUSTS...HAVE DECIDED TO EXPAND RED
FLAG WARNING TO INCLUDE FIRE ZONES 272 AND 273 AS WELL. WIND
SPEEDS MAY BE A BIT MARGINAL...BUT SHOULD STILL BE AROUND OR JUST
OVER 25 MPH GUSTS FOR MUCH OF THE AREA. MIXED LAYER WINDS ARE NOT
ALL TOO IMPRESSIVE...ONLY AROUND 20 KNOTS. BUT SHOULD BE ENOUGH
MOMENTUM TO SEE HIGHER GUSTS.

WILL ALSO BE WATCHING A COLD FRONT MOVING INTO THE WESTERN CWA
LATE THIS AFTERNOON. ALL HI RES MODELS ARE SHOWING SCT ACTIVITY
MOVING INTO CORSON AND DEWEY COUNTIES AFTER 21Z SO HAVE INCREASED
POPS AND WENT WITH COVERAGE WORDING INSTEAD OF UNCERTAINTY. HI RES
SIMULATED REFLECTIVITY ALSO SUGGESTING ACTIVITY HOLDS TOGETHER
ALONG THE FRONT IN SOME FORM OF A BROKEN LINE AS IT TRACKS EAST
ACROSS THE CWA. HAVE INCREASED POPS OVERNIGHT A BIT AS WELL AND
CONTINUED THE COVERAGE WORDING. ONLY MINIMAL INSTABILITY PRESENT
BUT JUST ENOUGH TO SUPPORT SOME EMBEDDED THUNDERSHOWERS AS WELL.
ACTIVITY ASSOCIATED WITH THIS FRONT LOOKS TO CLEAR THE CWA BY 12Z
FRIDAY.

FRIDAY ITSELF LOOKING VERY PLEASANT AS SFC HIGH PRESSURE MOVES
ACROSS THE REGION. WINDS WILL BE FAIRLY LIGHT WITH SUNNY SKIES AND
TEMPS IN THE 70S FOR HIGHS. WILL CONTINUE WITH DRY CONDITIONS
FRIDAY NIGHT. ON SATURDAY...MID LEVEL TEMPS WARM QUITE A BIT AS
SOUTHERLY FLOW INCREASES. GOOD MIXING DEVELOPS BY AFTERNOON WITH
IMPRESSIVE WARMING AT THE SFC. WIDESPREAD 80S ARE EXPECTED AND
ANTICIPATE SATURDAY TO BE THE WARMEST DAY OF THE SPRING THUS FAR.
WILL ALSO HAVE TO WATCH THE ARRIVAL OF A SFC TROUGH SATURDAY
AFTERNOON WHICH COULD SPARK A FEW SHOWERS OR STORMS. MOISTURE MAY
BE LIMITED SO WILL ONLY INCLUDE SLIGHT CHANCE POPS AT THIS TIME.


.LONG TERM...(SATURDAY EVENING THROUGH WEDNESDAY)
ISSUED AT 347 AM CDT THU APR 30 2015

A WEAK FRONT/TROUGH WILL MOVE THROUGH THE PLAINS ON SAT
NIGHT/SUNDAY BRINGING A CHANCE OF SHOWERS AND TSTORMS. ZONAL FLOW
ALOFT AND HIGH PRESSURE NEAR THE SURFACE WILL KEEP SUNDAY NIGHT
THROUGH MONDAY NIGHT RELATIVELY QUIET...THOUGH SUPERBLEND KEEPS
SOME POPS ACROSS THE SOUTHERN CWA DUE TO A WEAK SHORTWAVE THAT MAY
BRING SHOWERS.

THE PATTERN BEGINS TO SHIFT TUESDAY NIGHT AS A POTENT UPPER LOW
STARTS TO MOVE EAST. COUPLED WITH SOUTHERLY FLOW AT THE SFC AHEAD
OF AN APPROACHING ATMOSPHERICALLY STACKED LOW AND AN OPEN GULF
STARTING ON WED PRECIP CHANCES WILL INCREASE GREATLY. BOTH THE
ECMWF AND THE GFS ARE IN GOOD AGREEMENT ON THIS MID WEEK SYSTEM.
IF THIS PATTERN PERSISTS AND IT DOES NOT SHIFT SOUTH AS HAS BEEN
THE TREND...THIS LOW WILL BE ONE OF THE MORE WELL DEVELOPED
SYNOPTIC SYSTEMS THE REGION HAS SEEN ALL YEAR.

TEMPERATURES WILL CLIMB INTO THE 70S THROUGH THE PERIOD.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1225 PM CDT THU APR 30 2015

VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THROUGH THE TAF
PERIOD. LOOK FOR A LINE OF RAIN SHOWERS TO PUSH ACROSS THE CWA
DURING THE LATE AFTERNOON AND OVERNIGHT HOURS. AN ISOLATED
THUNDERSTORM OR TWO ARE POSSIBLE AS WELL...BUT WILL NOT MENTION IN
ANY TAF SITES DUE TO UNCERTAINTY OF WHERE DEVELOPMENT MAY BE.

&&


.ABR WATCHES/WARNINGS/ADVISORIES...
SD...RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR SDZ269-271>273.

MN...NONE.
&&

$$

UPDATE...CONNELLY
SHORT TERM...TMT
LONG TERM...WISE
AVIATION...PARKIN





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