Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 040515
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1215 AM CDT SAT JUL 4 2015

.UPDATE...
ISSUED AT 713 PM CDT FRI JUL 3 2015

TOOK OUT CHANCES OF SHOWERS/THUNDERSTORMS THIS EVENING. SINCE
DEVELOPMENT HAS OCCURRED AS OF YET...CHANCES ARE EXTREMELY LOW
THAT ANY DEVELOPMENT OF CONVECTION WILL OCCUR THIS EVENING AS THE
SUN SETS AND DECREASES ANY MEAGER INSTABILITY THAT WE MAY HAVE
HAD.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM CDT FRI JUL 3 2015

MAP ANALYSIS INDICATES UPPER TROPOSPHERIC RIDGING OVER THE
WESTERN CONUS AND TROUGHING OVER THE EAST. ENHANCED UPPER
TROPOSPHERIC FLOW EXTENDS FROM THE NORTHWESTERN CONUS...SOUTHEAST
INTO THE CENTRAL CONUS AND THEN EAST INTO THE OHIO RIVER VALLEY.
UPPER TROPOSPHERIC FLOW OVER OUR AREA MAXES OUT AT AROUND 60KTS
NEAR 36000FT AGL PER 12Z SOUNDING DATA FROM KLBF AND KOAX. AT THE
SURFACE AN AREA OF HIGH BAROMETRIC PRESSURE EXISTS ACROSS THE
CENTRAL PLAINS...THUS RESULTING IN A LIGHT AND VARIABLE BOUNDARY-
LAYER WIND FIELD ACROSS OUR AREA.

GUIDANCE SUGGESTS NORTHWESTERLY UPPER TROPOSPHERIC FLOW WILL PERSIST
OVER THE CENTRAL PLAINS THROUGH THE NEXT 24 HOURS...ALTHOUGH THIS
FLOW IS ALSO EXPECTED WEAKEN TONIGHT AND INTO THE DAY SATURDAY. AT
THE SURFACE...THE RIDGE OF HIGH BAROMETRIC PRESSURE CURRENTLY OVER
OUR AREA IS EXPECTED TO MOVE SOUTHEAST...AWAY FROM OUR
AREA...THROUGH THE NEXT 24 HOURS. THIS SHOULD ALLOW THE BOUNDARY-
LAYER WIND FIELD TO BECOME MORE ESTABLISHED FROM THE SOUTH/SOUTHEAST
DURING THE DAY SATURDAY.

ALTHOUGH BY NO MEANS LIKELY...A COUPLE SETS OF GUIDANCE CONTINUE
TO SUGGEST INCREASING LOWER TO UPPER TROPOSPHERIC LAPSE RATES
COULD PROMOTE ISOLATED CONVECTION THIS AFTERNOON INTO THIS
EVENING...ESPECIALLY ACROSS PORTIONS OF SOUTH CENTRAL NEBRASKA
GENERALLY ALONG AND WEST OF HIGHWAY 281. POPS WERE ALREADY IN
EXISTENCE IN THE FORECAST ACROSS THIS AREA FOR THIS AFTERNOON AND
EVENING. GIVEN ALL THIS...OPTED TO GO AHEAD WITH 20% POPS LATE
THIS AFTERNOON INTO THIS EVENING...AGAIN...PRIMARILY ACROSS SOUTH
CENTRAL NEBRASKA ALONG AND WEST OF HIGHWAY 281.

AN OVERALL LACK IN OMEGA SHOULD THEN KEEP US DRY TONIGHT AND THROUGH
MUCH OF SATURDAY. THAT SAID...THERE REMAIN SUBTLE SIGNS OF ISOLATED
CONVECTION ONCE AGAIN BEING POSSIBLE ACROSS PORTIONS OF THE AREA
PRIMARILY WEST OF HIGHWAY 281 STARTING LATE SATURDAY AFTERNOON.
GIVEN THIS...ALSO WENT AHEAD WITH 20% POPS FOR WESTERN PORTIONS OF
THE AREA STARTING LATE SATURDAY AFTERNOON.

AT THIS TIME IT DOES NOT APPEAR POTENTIAL ENERGY WILL BE MUCH
GREATER THAN 1000J/KG BOTH TODAY AND SATURDAY. ALTHOUGH DEEP-LAYER
BULK SHEAR WILL BE A TOUCH MORE RESPECTABLE AT ~30KTS...THE
PROBABILITY OF SEVERE WEATHER BOTH TODAY AND SATURDAY APPEARS VERY
LOW AND AS A RESULT...WILL LEAVE OUT ANY MENTION OF SEVERE WEATHER
IN THE HWO.

.LONG TERM...(SATURDAY EVENING THROUGH FRIDAY)
ISSUED AT 300 PM CDT FRI JUL 3 2015

PRECIPITATION-WISE: TAKING A BROAD OVERVIEW OF THIS 6-DAY
PERIOD...THERE ARE GENERALLY THREE WINDOWS OF OPPORTUNITY FOR
SHOWERS/THUNDERSTORMS: 1) A STILL UNCERTAIN/IFFY SLIGHT CHANCE
SATURDAY EVENING/NIGHT MOST AREAS AND THEN LINGERING IN SOUTHEAST
COUNTIES SUNDAY MORNING. 2) A HIGHER CONFIDENCE OF MORE WIDESPREAD
CONVECTIVE COVERAGE SUNDAY EVENING INTO MONDAY...WHICH COULD
FEATURE THE RISK OF AT LEAST A FEW SEVERE STORMS ESPECIALLY NORTH
OF HIGHWAY 6 IN NEBRASKA SUNDAY EVENING/NIGHT...AND THEN 3)
VARIOUS...MAINLY LOW-CONFIDENCE CHANCES SEVERAL DAYS AWAY FROM NOW
IN THE WEDNESDAY-FRIDAY TIME FRAME. SANDWICHED IN BETWEEN THESE
AFOREMENTIONED STORM CHANCES IS A REASONABLY HIGH-CONFIDENCE
STRETCH OF DRY WEATHER FOR THE MONDAY NIGHT THROUGH TUESDAY NIGHT
TIME FRAME (SAVE FOR A SMALL CHANCE OF LINGERING STORMS RIGHT
MONDAY EVENING IN A FEW SOUTHEAST COUNTIES).

SEVERE WEATHER CHANCES: STARTING OFF WITH THE FIRST...SLIGHT
CHANCE OF STORMS SATURDAY EVENING INTO SUNDAY MORNING...THIS IS
ONE OF THOSE SITUATIONS WHERE ALTHOUGH A FEW SEVERE STORMS ARE
PROBABLY NOT OUT OF THE QUESTION...AND NOT TO MENTION THE LATEST
SPC DAY 2 OUTLOOK NOW PUTS THE MAJORITY OF THE WESTERN 1/2 OF THE
CWA INTO A MARGINAL RISK WITH A SLIGHT RISK FAR WEST...THE
CONFIDENCE IN HAVING MUCH IN THE WAY OF THUNDERSTORM DEVELOPMENT
IN THE FIRST PLACE CURRENTLY ARGUES TO "DOWNPLAY" THIS RISK A BIT
FOR NOW. AS A RESULT...WILL ACKNOWLEDGE SOME STRONG STORM
POTENTIAL IN THE LATEST HAZARDOUS WEATHER OUTLOOK (HWOGID) BUT
FOREGO A SEVERE MENTION. CERTAINTLY A BIT GREATER RISK FOR A FEW
SEVERE STORMS LOOKS TO ARRIVE FOR THE SUNDAY EVENING/NIGHT TIME
FRAME DUE TO STRONGER MID-UPPER LEVEL FORCING AND LOW LEVEL
CONVERGENCE ALONG AN INVADING COLD FRONT. THAT BEING SAID...WITH
MOST OF THIS ACTIVITY EXPECTED TO OCCUR DURING THE NIGHT
HOURS...THE LOCAL RISK DOES NOT APPEAR TO BE AS HIGH AS AREAS
FARTHER NORTH/NORTHWEST...AND AGREE WITH SPC IN KEEPING THE VAST
MAJORITY OF THE DAY 3 SLIGHT RISK AREA NORTH OF THE CWA. FINALLY
FOR THE MID-LATE WEEK STORM CHANCES...INSTABILITY/SHEAR PARAMETERS
SUGGEST THAT AT LEAST ISOLATED SEVERE STORM COVERAGE CANNOT BE
RULED OUT...BUT IT IS JUST FAR TOO SOON TO HIGHLIGHT THESE CHANCES
WITH ANY KIND OF DETAIL.

TEMPERATURE-WISE: AS A WHOLE...THESE 6 DAYS LOOK TO AVERAGE NEAR
TO SLIGHTLY BELOW NORMAL FOR EARLY JULY...WITH THE LARGEST SWING
IN DAY-TO-DAY HIGH TEMPERATURES APPEARING TO COME RIGHT AWAY FROM
SUNDAY INTO MONDAY AS A COOL-DOWN TAKES PLACE IN THE WAKE OF A
SEASONABLY DECENT COLD FRONT. AHEAD OF THE FRONT ON SUNDAY...HAVE
NUDGED UP HIGHS VERY SLIGHTLY FROM PREVIOUS FORECAST AND
POTENTIALLY NOT ENOUGH...BUT AIMING FOR UPPER 80S/LOW 90S MOST
NEBRASKA ZONES AND MORE SO MID 90S IN KS. A FEW PLACES MAINLY IN
KS COULD ALSO FLIRT WITH 100-DEGREE HEAT INDEX VALUES...BUT THIS
IS STILL SAFELY SHORT OF ADVISORY CRITERIA OF 105. BEHIND THE
FRONT...HIGHS ON MONDAY ARE THEN ONLY AIMED INTO THE UPPER 70S-LOW
80S CWA-WIDE. THE REMAINDER OF THE WORK-WEEK THEN LOOKS TO FEATURE
HIGHS MAINLY IN THE LOW-MID 80S...ALTHOUGH A WARM-UP TO WITHIN A
FEW DEGREES EITHER SIDE OF 90 IS VERY PRELIMINARY ADVERTISED FOR
MOST OF THE CWA NEXT FRIDAY.

NOW TAKING A BRIEF LOOK AT DAILY DETAILS IN 12-24 HOUR BLOCKS:

SATURDAY EVENING/NIGHT: EVEN AT THIS REASONABLY CLOSE TIME
RANGE...UNFORTUNATELY THERE IS STILL SOME UNCERTAINTY REGARDING
WHETHER OR NOT INDEPENDENCE DAY ACTIVITIES MAY BE AFFECTED BY HIT
AND MISS STORM ACTIVITY...AS MODELS SUCH AS THE NAM AND 4KM WRF-
NMM/ARW LARGELY SUGGEST A MAINLY DRY PERIOD...WHILE OTHER MODELS
(ESPECIALLY THE GFS) ARE MORE ROBUST WITH MORE WIDESPREAD
CONVECTION...WHICH SEEMS A BIT SUSPECT GIVEN RATHER WEAK FORCING
AND AT LEAST WEAK CAPPING. AS A COMPROMISE BETWEEN THE
POSSIBILITIES...WILL MAINTAIN A TOKEN SLIGHT CHANCE OF
SHOWERS/STORMS THROUGH THE EVENING/NIGHT...BUT WANT TO EMPHASIZE
FOR THOSE WITH OUTDOOR INTERESTS THAT THERE IS A MUCH HIGHER
CHANCE OF THINGS REMAINING DRY THROUGH THE EVENING THAN TURNING
WET/STORMY. IN OTHER WORDS...NOBODY SHOULD BE CHANGING THEIR PLANS
JUT YET FOR THE CURRENT SLIGHT CHANCES.

SUNDAY DAYTIME-NIGHT: OTHER THAN A SLIGHT CHANCE OF LINGERING
CONVECTION MAINLY IN SOUTHEAST ZONES DURING THE MORNING...HAVE
MAINTAINED THE THINKING OF A DRY/CAPPED AFTERNOON WITH BREEZY
SOUTHERLY WINDS AHEAD OF THE APPROACHING COLD FRONT. THEN AS THE
SURFACE COLD FRONT INVADES SUNDAY NIGHT AND UPPER LEVEL FORCING
INCREASES AS A SEASONABLY STRONG SHORTWAVE TROUGH PASSES THROUGH
THE NORTHERN PLAINS...SHOWER/STORM CHANCES RAMP UP AS WELL.

MONDAY DAYTIME-NIGHT: ALTHOUGH INSTABILITY STEADILY FADES AWAY TO
THE SOUTH WITH TIME...DECENT SHOWER/WEAK STORM CHANCES CONTINUE
INTO THE DAY. WILL LEAVE A LOW-END CHANCE IN SOUTHEAST ZONES IN
THE EVENING...BUT THE VAST MAJORITY OF THE CWA SHOULD BE DRY.

TUESDAY-TUESDAY NIGHT: THIS IS LOOKING LIKE A DRY 24 HOURS AS
SURFACE HIGH PRESSURE RULES THE LOW-LEVEL SCENE IN THE WAKE OF THE
DEPARTING SYSTEM.

WEDNESDAY DAYTIME-FRIDAY DAYTIME: AS MENTIONED
ABOVE...VARIOUS...MAINLY LOW-CONFIDENCE STORM CHANCES RETURN TO
THE LOCAL AREA IN QUASI-ZONAL FLOW...ALTHOUGH IT IS WORTH NOTING
THAT THE GFS IS CONSIDERABLY "WETTER" THAN THE ECMWF IN THE RAW
QPF FIELDS.

&&

.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1211 AM CDT SAT JUL 4 2015

HAVE MAINTAINED VFR CONDITIONS THRU THE TAF PERIOD. WINDS ARE
EXPECTED TO REMAIN LIGHT AND VARIABLE OVERNIGHT UNDER THE
INFLUENCE OF A SURFACE RIDGE. AS THE RIDGE SHIFTS EAST...WINDS
WILL TRANSITION SOUTHERLY MID MORNING SATURDAY. CANNOT COMLETELY
RULE OUT THE POTENTIAL FOR A ROGUE SHOWER OR STORM LATE SATURDAY
HOWEVER CHCS ARE NOT GREAT ENOUGH TO INCLUDE IN TAFS ATTM.

&&

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

&&

$$

UPDATE...HEINLEIN
SHORT TERM...BRYANT
LONG TERM...PFANNKUCH
AVIATION...FAY


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