Area Forecast Discussion
Issued by NWS Hastings, NE

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000
FXUS63 KGID 010505
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1205 AM CDT WED OCT 1 2014

.UPDATE...
ISSUED AT 1205 AM CDT WED OCT 1 2014

JUST PUBLISHED A SIGNIFICANT ENHANCED SHORT-TERM FCST /ESTF/
UPDATE.

WE MAY NEED A DENSE FOG ADVISORY FOR PARTS OF THE FCST AREA BEFORE
DAWN.

THIS AFTERNOON THERE WAS A SUBSTANTIAL DWPT BOUNDARY BISECTING THE
FCST AREA FROM BVN-GRI-PHG-HLC. STRATUS HAS DEVELOPED ON THE MOIST
SIDE. WINDS ARE CONSIDERABLY MORE SE THAN EXPECTED 24 HRS AGO AND
THIS HAS TRANSPORTED THESE HIGHER DWPTS NW. THE DWPT AT EAR
DROPPED TO 43F...BUT NOW WAS IN THE LOW 60S. SO FOG HAS DEVELOPED.
AND WHILE ODX/LXN ARE STILL 10SM CLR...THE TREND IS ESTABLISHED
AND THE GOES FOG PRODUCT HAS IT. STRATUS/FOG WILL BE INVADING
SHORTLY.

SO CLOUDS/FOG HAVE BEEN ADJUSTED THRU 18Z. AM NOT ANTICIPATING ANY
IMPROVEMENT IN FOG/STRATUS UNTIL 15Z. BASED ON INCREASING CLOUDS
...HAVE ADJUSTED TEMP/DWPTS UPWARD W OF HWY 183 WHERE THEY SHOULD
THEN HOLD STEADY THE REST OF THE NIGHT UNDER THE STRATUS.

THE HRRR IS INDICATING A WINDSHIFT TO THE W TO MOVE INTO THE WRN
HALF OF THE FCST AREA BEFORE SUNRISE. THIS COMPLICATES THE FCST
AND LOWERS CONFIDENCE AS IT COULD ADVECT LOWER DWPTS BACK IN...
REDUCING THE STRATUS/FOG. ANOTHER COMPLICATINO IS THE THICK MID-
HIGH CLOUDS OVER WRN NEB/KS ASSOCIATED WITH THE APPROACHING
SHORTWAVE TROF. THE AFFECT THESE CLOUDS WILL HAVE ON THE STRATUS
REMAINS UNCLEAR.

TSTMS CONT TO FORM BETWEEN HSI AND HJH. CONDITIONS WILL REMAIN
FAVORABLE FOR ADDITIONAL DEVELOPMENT OVERNIGHT. 88D ESTIMATES 3-4"
OF RAIN FELL OVER ERN THAYER COUNTY. THE AUTOMATED RAIN GAUGE AT
ALEXANDRIA MEASURED 3.31" SINCE 8 PM. SO WE WILL NEED TO MONITOR
HYDRO ISSUES.

&&

.SHORT TERM...(REST OF TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 258 PM CDT TUE SEP 30 2014

HEADING INTO THE OVERNIGHT HOURS TONIGHT...THE AXIS OF A ~40KT JET
STREAK JUST ABOVE THE BOUNDARY LAYER IS EXPECTED TO DEVELOP FROM
SOUTH CENTRAL KANSAS INTO SOUTHEASTERN NEBRASKA...WITH THE
NORTHWESTERN PERIPHERY OF THIS JET STREAK CLIPPING OUR
SOUTHEASTERN CWA. THERMAL ADVECTION ALONG THIS AXIS APPEARS AS
THOUGH IT WILL BE SUFFICIENT FOR PRECIPITATION PRODUCTION ACROSS
OUR SOUTHEAST...A SOLUTION SUPPORTED BY QPF FIELDS FROM THE
NAM...OPERATIONAL GFS AND EC. THAT SAID...SIMULATED REFLECTIVITY
FROM SEVERAL MODELS REMAIN VERY PESSIMISTIC WITH RESPECT TO
PRECIPITATION PRODUCTION ACROSS OUR AREA TONIGHT AND WITH THE
PRIMARY JET STREAK AXIS REMAINING TO OUR SOUTHEAST...IT CERTAINLY
SEEMS TO BE A FAIR ARGUMENT. THAT SAID...OF ANY TIME PERIOD
BETWEEN LATE THIS AFTERNOON AND 12Z WEDNESDAY...THE 03-09Z TIME
PERIOD SEEMS TO HOLD THE HIGHEST PROBABILITY OF PRECIPITATION
PRODUCTION ACROSS OUR EAST/SOUTHEAST AND AS A RESULT...WENT AHEAD
AND RELEGATED THE HIGHEST POPS...~50%...TO OUR SOUTHEAST 03-09Z
TONIGHT.

THE MORNING HOURS ON WEDNESDAY...POST-SUNRISE...WILL LIKELY
PRESENT A DRY PERIOD TO THE AREA AS THE AFOREMENTIONED LOWER
TROPOSPHERIC JET AXIS WEAKENS AND SHIFTS EAST OF THE AREA. DRY
CONDITIONS ARE FORECAST 12-18Z AS A RESULT. HEADING INTO WEDNESDAY
AFTERNOON AND EVENING HOWEVER...INCREASING UPPER TROPOSPHERIC
THERMAL ADVECTION AHEAD OF THE APPROACHING TROUGH AXIS TO OUR
WEST...WORKING IN CONCERT WITH THE THERMALLY-INDIRECT CIRCULATION
WITHIN THE LEFT- FRONT QUADRANT OF THE AFOREMENTIONED UPPER
TROPOSPHERIC JET STREAK...COULD BE ENOUGH TO PROMOTE PRECIPITATION
PRODUCTION MOST ANYWHERE ACROSS THE AREA. GIVEN ALL THIS...WENT
AHEAD WITH 20-40% POPS ACROSS MUCH OF THE CWA WEDNESDAY AFTERNOON
AND EVENING...WITH POPS INCREASING TO AROUND 70% AFTER 06Z
THURSDAY FOR MANY LOCATIONS AS THE UPPER TROPOSPHERIC TROUGH AXIS
DRAWS CLOSER TO THE AREA THUS RESULTING IN INCREASING OMEGA.

UPPER TROPOSPHERIC LAPSE RATES ARE NOT OVERLY IMPRESSIVE THIS
AFTERNOON AND EVENING WITH THE CLOSED LOW/SHORT WAVE REMAINING
WELL NORTHWEST OF OUR AREA. THAT SAID...AFTERNOON SURFACE DEW
POINT READINGS IN THE UPPER 50S TO LOWER 60S ARE HELPING PROMOTE
POTENTIAL ENERGY VALUES OF 1000-1500J/KG ACROSS OUR EAST
SOUTHEAST. DEEP-LAYER BULK SHEAR VALUES ON THE ORDER OF 40KTS ARE
ALSO IN EXISTENCE. GIVEN ALL THIS...IT CERTAINLY SEEMS
POSSIBLE...SHOULD CONVECTION BE REALIZED LATE THIS AFTERNOON AND
EVENING...THAT A FEW STRONG TO PERHAPS SEVERE STORMS COULD BE
REALIZED AND WILL CONTINUE SUCH MENTION IN THE HWO. LOOKING AHEAD
TO WEDNESDAY AFTERNOON AND EVENING...THE BOUNDARY-LAYER AIR MASS
SHOULD NOT CHANGE ALL THAT MUCH WHEN COMPARED TO TODAY...BUT UPPER
TROPOSPHERIC LAPSE RATES WILL BE ON THE INCREASE WITH THE TROUGH
AXIS APPROACHING FROM THE WEST AND AS A RESULT...WEDNESDAY
AFTERNOON/EVENING POTENTIAL ENERGY VALUES TO BE CLOSER TO
2000J/KG. IN ADDITION...INCREASING UPPER TROPOSPHERIC JET ENERGY
SHOULD ALSO RESULT IN INCREASING DEEP-LAYER BULK SHEAR...WITH
VALUES CLOSER TO 45 OR 50KTS EXPECTED ACROSS OUR SOUTHEASTERN CWA
ON WEDNESDAY. FINALLY...A BACKED BOUNDARY-LAYER WIND FIELD TO THE
SOUTH OF THE BAROCLINIC ZONE MAY ALSO PROMOTE LOCALLY ENHANCED
BOUNDARY-LAYER SRH VALUES THUS PROMOTING THE POSSIBILITY OF
TORNADIC ACTIVITY. GIVEN ALL THIS...WILL CONTINUE THE MENTION OF
SEVERE WEATHER...INCLUDING TORNADIC ACTIVITY...IN THE HWO FOR FOR
MUCH OF THE AREA ON WEDNESDAY AFTERNOON AND EVENING.


.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 258 PM CDT TUE SEP 30 2014

PRIMARY FORECAST CONCERNS THROUGH THE LONG TERM PERIOD LIE WITH
PRECIPITATION CHANCES RIGHT OFF THE BAT...THEN TEMPERATURES.

THE START OF THE PERIOD HAS MODELS IN PRETTY GOOD AGREEMENT WITH
THE OVERALL PATTERN ACROSS THE CONUS...WITH THE LATEST UPPER
LEVEL DISTURBANCE MAKING ITS WAY EAST INTO THE REGION. THIS
SHORTWAVE TROUGH AXIS IS SET UP JUST WEST OF THE CWA AT SUNRISE
THURSDAY...WITH THE INCREASED MID/UPPER LEVEL LIFT OUT AHEAD OF
THE AXIS BRINGING CONTINUED PRECIPITATION CHANCES TO MAINLY THE
EASTERN HALF OF THE CWA. AT THE SURFACE...TIMING/LOCATION OF THE
ACCOMPANYING COLD FRONT MATCHES UP FAIRLY WELL BETWEEN
MODELS...SHOWING IT EITHER RIGHT OVER THE SERN CORNER OF THE
CWA...OR JUST OUTSIDE THE CWA BOUNDARY. THROUGH THE DAYTIME
HOURS...THE MAIN STORY LIES WITH PRECIPITATION COMING TO AN
END...AND COOLER AIR BUILDING INTO THE REGION. DID INCREASE POPS
DURING THE MORNING HOURS WITH MODELS IN GOOD AGREEMENT SHOWING
THINGS HANGING A BIT LONGER...BUT TRENDED THINGS DOWN FOR THE
AFTERNOON HOURS. SOME UNCERTAINTY IN PLACE WITH HOW MUCH
INSTABILITY MAY LINGER...SO HAVE SOME SCATTERED THUNDER MENTION IN
THE EAST...WITH JUST SHOWERS IN THE AFTERNOON. SHOULD SEE
DIMINISHING SKY COVER WITH TIME...BUT GUSTY NORTHWEST WINDS LOOK
TO HANG ON FOR A GOOD CHUNK OF THE DAY. NO SIGNIFICANT CHANGES
WERE MADE TO HIGH TEMPS FOR THURSDAY...WHICH REMAIN IN THE
MID/UPPER 60S.

THURSDAY NIGHT...MORE AMPLIFIED NORTHWESTERLY FLOW IS EXPECTED TO
SET UP ACROSS THE CENTRAL CONUS...AS THE LATEST DISTURBANCE KEEPS
SHIFTING EAST AND RIDGING IS BUILDING ALONG THE WEST COAST. KEPT
THE DRY FORECAST GOING...BUT CONFIDENCE IS A LITTLE LOWER.
MODELS SHOWING THE AREA BEING IN THE EXIT REGION OF A HEFTY 120+KT
UPPER LEVEL JET STREAK NOSING IN FROM CENTRAL CANADA...THINKING
THAT THE ATMOSPHERE WILL REMAIN DRY ENOUGH TO KEEP THINGS
DRY...BUT THE LATEST ECMWF TRIES BRINGING ANOTHER SHORTWAVE
DISTURBANCE SOUTH INTO THE AREA...ALONG WITH ITS RESULTANT QPF.
WANT TO SEE IF THAT FEATURE REMAINS IN UPCOMING RUNS BEFORE
JUMPING ON BOARD. THE GFS KEEPS THAT DISTURBANCE WELL TO THE
NORTH...AND ANY PRECIP WOULD BE JET STREAK DRIVEN.

AS WE GET INTO FRIDAY...THAT NEXT DISTURBANCE MOVING THROUGH THE
MAIN FLOW WILL BRING A REINFORCING COLD FRONT THROUGH THE
REGION...AND LOOKS TO RESULT IN FRIDAY BEING THE COOLEST DAY OF
THE 7 DAY FORECAST PERIOD. SURFACE HIGH PRESSURE WILL SETTLE
INTO THE REGION FROM THE NW THROUGH THE DAY...BRINGING ANOTHER
SURGE OF COOLER AIR. EXPECTING MOSTLY CLEAR SKIES...AND ANOTHER
ROUND OF GUSTY NW WINDS...THOUGH THEY SHOULD START DIMINISHING
LATER IN THE AFTERNOON WITH THE SFC HIGH BECOMING MORE OF A
PLAYER. DID LOWER HIGHS A FEW DEGREES...WITH THE FORECAST NOW
RANGING FROM THE UPPER 50S IN THE NORTHEAST TO MID 60S IN THE SW.
BIGGEST CHANGE MADE TO FRIDAY WAS TO KNOCK DOWN DEWPOINTS. MODELS
ARE IN GOOD AGREEMENT SHOWING NOTABLY DRIER AIR WORKING IN...AND
FORECAST DEWPOINTS IN SOME LOCATIONS WERE DECREASED BY AROUND 10
DEGREES.

LOOKING AHEAD TO THE UPCOMING WEEKEND AND EARLY PART OF NEXT
WEEK...ANY NOTABLE CHANGES OCCURRED WITH TEMPERATURES...AS THE DRY
FORECAST REMAINS IN PLACE. MODELS REMAIN IN GOOD AGREEMENT
SHOWING THE UPPER LEVEL PATTERN REMAINING A WELL AMPLIFIED WITH
NWRLY FLOW IN PLACE ACROSS THE REGION AND ANY DISTURBANCES
EXPECTED TO REMAIN TO THE N/NE OF THE CWA. THE COOLEST PART OF THE
AIR MASS WHICH BUILDS IN AT THE END OF THE WEEK STARTS TO SHIFT
OFF TO THE EAST...BUT THROUGH THE WEEKEND THERE LOOKS TO BE ENOUGH
OF AN INFLUENCE OVER THE CWA TO KEEP HIGHS FOR SAT IN THE
MID/UPPER 60S...WITH ANOTHER BUMP UP INTO THE UPPER 60S TO MID 70S
FOR SUN. A PRETTY NICE WEEKEND...NOT A WHOLE LOT IN THE WAY OF
CLOUDS EXPECTED...AND WHILE SUNDAY MAY BE A TOUCH BREEZIER...SAT
WIND LOOK TO TOP OUT ARND 10 MPH. NO NOTABLE CHANGES EXPECTED AS
WE GET INTO MON/TUE...WITH HIGHS CLIMBING BACK INTO THE LOWER/MID
70S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 638 PM CDT TUE SEP 30 2014

THUNDERSTORMS THIS EVENING ARE EXPECTED TO REMAIN SOUTHEAST OF THE
TERMINAL...WITH GENERALLY ONLY PASSING MID/HIGH LEVEL CLOUDS FROM
TIME TO TIME. AS WINDS DIMINISH OVERNIGHT...THERE IS A CHANCE THAT
WITH SOME ADDITIONAL CLEARING WE COULD SEE SOME LIGHT FOG DEVELOP.
WHILE SOME GUIDANCE IS BRINGING DENSE FOG...OPTED NOT TO INCLUDE
THIS FOR THE TIME BEING AS CONFIDENCE IS LOW...RATHER INSERTED
MVFR VSBYS IN BR FOR THE TIME BEING. OTHERWISE...MID/HIGH LEVEL
CLOUDS WILL BE ON THE INCREASE DURING THE DAYTIME HOURS
WEDNESDAY...WITH GENERALLY LIGHT WESTERLY WINDS EXPECT AHEAD OF
THE NEXT DISTURBANCE...EXPECTED JUST BEYOND THE CURRENT VALID
PERIOD OF THE TAF.

&&

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

$$

UPDATE...HALBLAUB
SHORT TERM...BRYANT
LONG TERM...ADP
AVIATION...ROSSI


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