Area Forecast Discussion
Issued by NWS Hastings, NE

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000
FXUS63 KGID 292357
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
657 PM CDT SAT AUG 29 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 400 PM CDT SAT AUG 29 2015

IF NOT FOR ANOTHER CHANCE OF PESKY FOG (POSSIBLY SOME DENSE?) IN
MAINLY SOUTHEAST PORTIONS OF THE CWA...THIS WOULD BE A TRULY
"QUIET" NEXT 24 HOURS...AS THE RISK OF PRECIPITATION LITERALLY
REMAINS ZERO. OTHERWISE MADE ONLY MINOR TWEAKS TO THE GOING
FORECAST...AS COMPARED TO TODAY...SUNDAY SHOULD BE SLIGHTLY WARMER
(POTENTIALLY 5+ DEGREES WARMER IN FAR EASTERN COUNTIES) AND ALSO A
BIT BREEZIER OUT OF THE SOUTH-SOUTHEAST.

TAKING A LOOK AT THE HERE-AND-NOW AS OF 20Z/3PM...IT`S CERTAINLY
BEEN A QUIET DAY IN THE WAKE OF THE FAIRLY NARROW CORRIDOR OF
DENSE FOG THAT PLAGUED PRIMARILY THE HIGHWAY 281 CORRIDOR COUNTIES
THIS MORNING. WE ALSO HAD SOME STUBBORN LOW STRATUS THAT
EVENTUALLY VACATED FAR EASTERN/SOUTHEAST COUNTIES. AS A
RESULT...THE AFTERNOON HAS FEATURED HAZY/MILKY SUNSHINE...AS A
RESULT OF THE COMBINATION OF SOME THIN HIGH CLOUDS BUT MOSTLY
FROM WESTERN WILDFIRE SMOKE DRIFTING FAR OVERHEAD IN NORTHWEST
FLOW ALOFT. AT THE SURFACE...A WEAK AXIS OF HIGH PRESSURE IS
GENERALLY STRETCHED ACROSS THE CWA FROM SOUTHWEST-TO-
NORTHEAST...PROMOTING A LARGELY LIGHT/VARIABLE WIND REGIME.
TEMPERATURE-WISE...LOOKS LIKE THERE MIGHT BE A TOUCH MORE OF A
WEST-TO-EAST GRADIENT TODAY IN HIGHS THAN ORIGINALLY
THOUGHT...WITH FAR EASTERN COUNTIES ONLY MANAGING THE MID-UPPER
70S...WHILE FAR WESTERN COUNTIES ARE LOOKING AT UPPER 80S-LOW 90S.
IN THE MID-UPPER LEVELS...WATER VAPOR IMAGERY AND SHORT TERM
MODEL DATA CLEARLY DEPICT THE CENTRAL PLAINS RESIDING ALONG THE
NORTHEASTERN PERIPHERY OF AN EXPANSIVE...POSITIVELY-TILTED RIDGE
AXIS CENTERED OVER THE 4-CORNERS REGION. MEANWHILE...WAY OFF TO
THE NORTHWEST...A RATHER VIGOROUS TROUGH IS CENTERED OFF THE
PACIFIC NORTHWEST COAST.

NOW LOOKING FORWARD IN THE FORECAST THROUGH LATE SUNDAY
AFTERNOON...

THIS EVENING/TONIGHT: AS MENTIONED AT THE TOP...THE ONLY FLY IN
THE OINTMENT IS THE FOG POTENTIAL MAINLY SOUTHEAST. STARTING WITH
THE LARGE-SCALE PICTURE ALOFT...THE DOMINANT/POSITIVELY-TILTED
RIDGE REMAINS ANCHORED OVER THE AREA...SQUASHING ANY KIND OF
FORCING FOR PRECIP CHANCES. MEANWHILE AT THE SURFACE...THE RIDGE
AXIS WILL CONTINUE A SLOW EASTWARD MOVE...BECOMING CENTERED ALONG
AN AXIS FROM FAR SOUTHEAST NEB INTO NORTHEAST KS BY NIGHT`S END.
AS A RESULT...MOST OF THE CWA WILL SEE A GRADUAL TRANSITION FROM
LIGHT EASTERLY BREEZES TO LIGHT SOUTHERLY...WITH SPEEDS LARGELY
BELOW 6-8 MPH. DUE TO BEING IN CLOSEST PROXIMITY TO THE DEPARTING
RIDGE AXIS...OUR FAR SOUTHEAST COUNTIES (GENERALLY SOUTHEAST OF A
YORK-SUPERIOR-TIPTON KS LINE) ARE LIKELY TO EXPERIENCE THE OVERALL
LIGHTEST/NEAR-CALM BREEZES. FURTHERMORE...AS EVIDENCED BY THE
CURRENT POSITION OF THE LOW STRATUS DECK THAT HAS ONLY MANAGED TO
DRIFT 10-30 MILES AWAY FROM THE SOUTHEAST EDGES OF THE CWA...THERE
IS A CHANCE THAT SOME OF THIS ENHANCED LOW LEVEL MOISTURE WILL
ADVECT BACK NORTHWESTWARD INTO THE CWA AS LOW-LEVEL BREEZES TURN
MORE SOUTHEASTERLY. ALTHOUGH HAVE KEPT SKY COVER IN THE MOSTLY
CLEAR RANGE TONIGHT ALL AREAS...THERE IS A CHANCE THAT A
POTENTIALLY SOLID AREA OF LOW STRATUS OVER NORTHEAST KS COULD IN
FACT DRIFT BACK INTO OUR SOUTHEAST ZONES AND CLOUD THINGS OVER. OF
GREATER CONCERN IS THE POTENTIAL FOR AREAS OF FOG TO
FORM...ESPECIALLY ALONG THE EDGE OF ANY POTENTIAL STRATUS
DECK...WHICH IS EXACTLY WHAT HAPPENED THIS MORNING ALONG THE HWY
281 CORRIDOR. AT ANY RATE...MAINTAINED THE GENERIC "PATCHY FOG"
FROM PREVIOUS FORECAST FOR AREAS GENERALLY EAST OF A GREELEY-
MINDEN-OSBORNE LINE FOR LATE TONIGHT THROUGH AROUND 9-10 AM SUNDAY
MORNING...BUT BEEFED UP PLACES GENERALLY SOUTHEAST OF THE
AFOREMENTIONED YORK-SUPERIOR-TIPTON LINE TO "AREAS OF FOG WITH
VISIBILITY LESS THAN 1 MILE". BASED ON THE LATEST VISIBILITY
PRODUCTS FROM MODELS SUCH AS THE RAP/HRRR/NAM12...WE MAY VERY WELL
BE HEADING TOWARD ANOTHER ROUND OF EARLY MORNING DENSE FOG IN THIS
AREA...BUT CONFIDENCE IS FAR TOO LOW AT THIS TIME TOO PLAY UP THE
DENSE FOG POTENTIAL ENOUGH TO JUSTIFY AN ADVISORY. AT LEAST FOR
NOW THOUGH...WILL BE INTRODUCING THE POSSIBILITY OF SOME FOG
ISSUES INTO THE HAZARDOUS WEATHER OUTLOOK (HWOGID). AS FOR LOW
TEMPS TONIGHT...GENERALLY NUDGED MOST PLACES DOWN 1-2 DEGREES FROM
PREVIOUS FCST...AIMING MOST OF THE CWA INTO THE 57-59 RANGE.

SUNDAY DAYTIME: HAVE ALREADY COVERED EARLY MORNING FOG/STRATUS
CONCERNS IN THE PREVIOUS PARAGRAPH SO REFER TO IT FOR THE
DETAILS...BUT AS IS USUALLY THE CASE IN THE SUMMER WOULD EXPECT
ANY IMPACTFUL FOG TO DISSIPATE BY NO LATER THAN 15Z/10 AM.
OTHERWISE...IN THE MID-UPPER LEVELS...IF ANYTHING THE HEART OF THE
RIDGE AXIS BECOMES EVEN MORE CENTERED OVER THE LOCAL
REGION...AGAIN SQUASHING ANY RISK OF RAINFALL. MEANWHILE AT THE
SURFACE...THE RIDGE AXIS KEEPS DEPARTING EAST TOWARD THE MS RIVER
OVER THE COURSE OF THE DAY. IN ITS WAKE...THE COMBINATION OF
RETURN-FLOW CLOCKWISE AROUND THE HIGH...ALONG WITH THE DEVELOPMENT
OF A MODEST HIGH PLAINS LEE TROUGH TO THE WEST...WILL PROMOTE
INCREASING SOUTH-SOUTHEAST BREEZES THROUGH THE DAY. IN
GENERAL...SUSTAINED SPEEDS DURING THE AFTERNOON SHOULD AVERAGE
10-15 MPH IN THE SOUTHEAST 1/2 OF THE CWA...AND MORE-SO 15-20 MPH
IN NORTHWEST ZONES (WITH HIGHER GUSTS OF COURSE). ASSUMING THAT
SKIES AGAIN AVERAGE NO WORSE THAN MOSTLY SUNNY...CONFIDENCE IN
TEMPS IS FAIRLY HIGH AND MADE VERY LITTLE CHANGE FROM PREVIOUS
FORECAST. THIS MEANS MOST OF THE CWA IS AIMED INTO THE 86-90
RANGE...BUT WITH READINGS POSSIBLY A COUPLE DEGREES COOLER THAN
THIS IN FAR NORTHEAST COUNTIES (SUCH AS YORK/POLK) AND A FEW
DEGREES WARMER IN FAR SOUTHWEST COUNTIES (SUCH AS FURNAS/ROOKS).

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 400 PM CDT SAT AUG 29 2015

WE START OFF THE LONG TERM FORECAST WITH A POSITIVELY TILTED RIDGE
STRETCHING FROM THE DESERT SOUTHWEST INTO THE CENTRAL PLAINS AND A
CONSIDERABLE LONGWAVE TROUGH SETTLING INTO THE NORTHWESTERN UNITED
STATES WITH THE ASSOCIATED UPPER LOW WELL UP IN ALASKA. LEE SIDE
SURFACE TROUGH TO THE WEST AND A COLD FRONT WELL TO THE NORTHWEST
STRETCHING FROM THE NORTHERN PLAINS...SOUTHWEST INTO THE NORTH
CENTRAL ROCKIES AND INTO THE GREAT BASIN.

THE UPPER HIGH WILL RETREAT SOMEWHAT TO THE SOUTHEAST THROUGH THE
LONG TERM FORECAST AS THE NORTHWESTERN TROUGH EVENTUALLY AMPLIFIES
BUT MAKES LITTLE HEADWAY TO THE EAST/SOUTHEAST. THIS WILL
ESSENTIALLY KEEP US WITHIN GENERALLY WEAK SOUTHWEST FLOW ALOFT AND
IN THE SURFACE WARM SECTOR...AND LITTLE IF ANY CHANCE OF
PRECIPITATION FOR THE DURATION OF THE LONG TERM FORECAST...KEEPING
US WITHIN A REGIME OF SEASONABLY WARM 80S/90S FOR HIGHS AND SOMEWHAT
HUMID DEWPOINTS IN THE LOWER TO MID 60S...AT LEAST FOR SOUTH CENTRAL
NEBRASKA/NORTH CENTRAL KANSAS STANDARDS FOR THIS TIME OF YEAR.
HAVING SAID THIS...OUR CHANCES FOR PRECIPITATION ARE NOT EXACTLY
ZERO. BY MONDAY NIGHT...MOST LIKELY VERY LATE...A FRONTOLYTIC COLD
FRONT/TROUGH IS EXPECTED TO MAKE JUST ENOUGH HEADWAY TO MAKE ITS WAY
INTO OUR AREA AND COULD SLOWLY MAKE ITS WAY THROUGH BY TUESDAY
NIGHT. AT THE SAME TIME...A LOW-AMPLITUDE PERTURBATION IS FORECAST
TO MAKE ITS WAY INTO THE AREA WITHIN SOUTHWEST FLOW SOMETIME BETWEEN
LATE SUNDAY NIGHT THROUGH TUESDAY NIGHT...DEPENDING ON WHAT
OPERATIONAL MODEL OR ENSEMBLE YOU LOOK AT. I KEPT CHANCES PRETTY
LOW...MAY A BIT HIGHER IN OUR NORTHWEST LATE MONDAY NIGHT INTO
TUESDAY. CONVECTION COULD ALSO GET A BOOST AHEAD OF THE BOUNDARY AT
850 MB BY A MODEST LOW-LEVEL JET.

THE NEXT SHOT AT SOME PRECIPITATION WILL COME THURSDAY NIGHT INTO
SATURDAY AS ANOTHER BOUNDARY AND LOW-AMPLITUDE WAVE/S ARRIVE...WITH
THE BEST SHOT LANDING ON FRIDAY NIGHT THE WAY IT LOOKS RIGHT NOW.
WITH THIS TYPE OF PATTERN...I AM RELUCTANT TO GO WITH 50 PERCENT
CHANCE OF PRECIPITATION FRIDAY NIGHT THAT THE SUPERBLEND
INITIALIZATION IS ADVERTISING...SO I AM GENERALLY KNOCKING THIS DOWN
TO 30 AT MOST FOR NOW. PREDICTABILITY WOULD BE TOO LOW TO SPECULATE
SEVERE CHANCES FOR THESE PERIODS FOR NOW.

&&

.AVIATION...(FOR THE 00Z KGRI/KEAR TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 642 PM CDT SAT AUG 29 2015

LATEST GUIDANCE IS CONTINUING TO INDICATE THAT WE COULD SEE SOME
FOG DEVELOP ACROSS THE REGION OVERNIGHT. WITH WINDS SHIFTING AND
BECOMING LIGHT AND OUT OF THE SOUTHEAST...THIS SEEMS REASONABLE.
OPTED TO INTRODUCE SOME LIGHT BR TO KEAR AFT ABOUT 30/09Z...WITH 1
SM BR NOW IN THE FORECAST FOR KGRI AFT 30/10Z. ALSO INTRODUCED
SOME BKN IFR CIGS AT BOTH TERMINALS AS IT IS NOT OUT OF THE
QUESTION THAT STATUS COULD REDEVELOP OR ADVECT NORTHWESTWARD
TOWARDS THE TERMINALS DURING THE LATE NIGHT HOURS. ONCE THE
STRATUS/BR BURNS OFF IN THE MORNING...EXPECT INCREASING SOUTHERLY
WINDS TO 10KTS AND MAINLY CLEAR SKIES FOR THE REST OF THE PERIOD.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...ROSSI


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