Area Forecast Discussion
Issued by NWS Hastings, NE

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000
FXUS63 KGID 020925
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
425 AM CDT WED SEP 2 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM CDT WED SEP 2 2015

COMPARED TO THE PREVIOUS FORECAST...NO "MAJOR" CHANGES HAVE BEEN
MADE THROUGH THESE NEXT 24 HOURS...AS SMALL 20 PERCENT PRECIP
CHANCES (POPS) CONTINUE IN A HANDFUL OF SOUTHEAST COUNTIES BOTH
THIS MORNING AND AGAIN LATE TONIGHT...WHILE THE MAJORITY OF THE
CWA SEES LITTLE TO NO CHANCE OF RAIN (BUT NOT NECESSARILY "ZERO"
EITHER...MORE ON THAT BELOW). OTHERWISE...IF ANYTHING HAVE NUDGED
UP HIGH TEMPS TODAY 1-2 DEGREES...AS FOR THE CWA AS A WHOLE THIS
COULD BE THE OVERALL-HOTTEST DAY IN EXACTLY 1 MONTH (SINCE AUG.
2ND). FORTUNATELY...HEAT INDEX VALUES THIS AFTERNOON SHOULD HOLD
AT LEAST A FEW DEGREES BELOW THE 100-MARK...THUS AT LEAST STAYING
OUT OF TRULY DANGEROUS TERRITORY. AS WAS THE CASE YESTERDAY...AT
LEAST THE HEAT WILL BE ACCOMPANIED BY A SOUTHERLY BREEZE...ALTHOUGH
HAVE ACTUALLY LOWERED THESE FORECASTED WINDS A FEW MPH FROM
PREVIOUS IN MOST AREAS AS WELL.

STARTING OFF WITH A LOOK AT THE CURRENT SCENE AS OF 08Z/3AM...THE
VAST MAJORITY OF THE CWA FINDS ITSELF WITH ANOTHER DRY AND
SEASONABLY BALMY NIGHT UNDER NO-WORSE-THAN MOSTLY CLEAR SKIES. A
CONCENTRATED NORTH-SOUTH CORRIDOR OF SHOWERS AND NON-SEVERE
THUNDERSTORMS HAS FOCUSED 100+ MILES EAST OF THE CW MAINLY WITHIN
IA/NORTHWEST MO/FAR SOUTHEAST NEB...IN A REGION WHERE A DECENT LOW
LEVEL JET EXIT REGION (EVIDENT AT 850 MILLIBARS) IS POINTED INTO
AN AREA OF SLIGHTLY COOLER MID LEVEL TEMPS. WITHIN THE CWA...THERE
HAVE ACTUALLY BEEN A COUPLE VERY TINY SHOWERS BRIEFLY SPRING UP
DURING THE NIGHT FROM A PATCH OF ACCAS CLOUDS...ONE NEAR GRAND
ISLAND AND ONE NEAR CLARKS...BUT THESE HAVE HARDLY AMOUNTED TO
ANYTHING. IN THE LARGE SCALE OF THE MID-UPPER LEVELS...WATER VAPOR
SATELLITE AND SHORT-TERM MODEL DATA REVEAL WEST-SOUTHWEST FLOW
ALOFT OVER THE LOCAL AREA...BEING DIRECTED CLOCKWISE AROUND THE
NORTHERN PERIPHERY OF A RIDGE CENTERED OVER SOUTHERN PORTIONS OF
THE NM/TX BORDER AREA. MEANWHILE...A VIGOROUS TROUGH REMAINS WELL
OFF TO THE NORTHWEST ALONG THE BRITISH COLUMBIA COAST. CLOSER TO
HOME...A LOW-AMPLITUDE SHORTWAVE IS IN THE PROCESS OF DEPARTING
EASTWARD ACROSS THE MN/IA/NORTHEAST NEB AREA...WHICH IS ALSO
HELPING SPARK THE MORE WIDESPREAD CONVECTION OFF TO OUR EAST.
FARTHER SOUTHWEST...THERE ARE VERY SUBTLE HINTS OF A POSSIBLE WEAK
WAVE MOVING INTO SOUTHWEST KS. AT THE SURFACE EARLY THIS
MORNING...A WEAK SURFACE TROUGH REMAINS OFF TO THE WEST...WITH A
MODEST PRESSURE GRADIENT IN PLACE OVER MAINLY SOUTHEAST PARTS OF
THE CWA AND WEAKER NORTHWEST. THIS IS RESULTING IN RATHER LIGHT
SOUTHERLY BREEZES IN WESTERN ZONES...WHILE EAST-SOUTHEAST COUNTIES
ARE SEEING MORE OF A STEADY BREEZE AROUND 10+ MPH WITH SOME HIGHER
GUSTS. TEMP-WISE...LOWS ARE ON TRACK TO BOTTOM OUT A FEW DEGREES
EITHER SIDE OF 70 MOST AREAS...EXCEPT FOR MID-60S IN SEVERAL
WESTERN/NORTHERN COUNTIES.

BEFORE GOING INTO FORECAST DETAILS...FIRST A FEW COMMENTS
REGARDING THE PRECIP/POP CHANCES. IN SHORT...THIS IS ONE OF THOSE
FORECASTS WHERE YOU KNOW THAT THE VAST MAJORITY OF THE CWA SHOULD
STAY DRY...BUT NOT NECESSARILY EVERYBODY...WHICH ALWAYS CREATES A
BIT OF A CHALLENGE MESSAGE-WISE GIVEN THAT THE OFFICIAL FORECAST
ONLY MENTIONS RAIN CHANCES IF THEY ARE AT/ABOVE 15 PERCENT. THERE
ARE ALWAYS A FEW OPTIONS HERE...INCLUDING...1) BLANKETING THE
ENTIRE CWA WITH LOW 15-20 POPS JUST TO "COVER ONE-SELF" IF IT
DOES RAIN...2) LEAVE ALL AREAS BELOW 15 PERCENT AND NOT ADVERTISE
ANY CHANCES AT ALL GIVEN THEY ARE SO SMALL...OR 3) GIVE YOUR BEST
SHOT TO ONLY ADVERTISE 15+ SLIGHT CHANCES WHERE THEY SEEM "MOST
PROBABLE" WHILE OPENLY CONCEDING THAT CHANCES ELSEWHERE ARE NOT
NECESSARILY "ZERO"...JUST CLOSER TO 10 PERCENT THAN 20. IN THIS
CASE...OPTION 3 HAS BEEN IMPLEMENTED...AS ALTHOUGH ALL SLIGHT POPS
ARE CURRENTLY FOCUSED IN SOUTHEAST COUNTIES...WOULD NOT BE TOTALLY
SHOCKED TO SEE A FEW ROGUE SHOWERS/WEAK STORMS FLARE UP ELSEWHERE
AT SOME POINT.

FINALLY LOOKING AHEAD FORECAST-WISE OVER THESE NEXT 24 HOURS IN
GENERALLY 8-12 HOUR BLOCKS...

THROUGH MID-DAY (ROUGHLY NOON): WHILE THE PRIMARY LOW LEVEL JET
BRANCH SHOULD CONTINUE VEERING AND FOCUSING THE MAJORITY OF
REGIONAL CONVECTION WELL TO OUR EAST...THERE ARE HINTS IN A FEW
MODELS THAT A SECONDARY WEAK LOW LEVEL JET MAX COULD YET SPARK A
NEW AREA OF AT-LEAST ISOLATED SHOWERS/WEAK STORMS IN OR NEAR THE
FAR SOUTHERN/SOUTHEASTERN FRINGES OF THE CWA...AND THIS DOES NOT
SEEM COMPLETELY OUT OF THE QUESTION GIVEN THE PRESENCE OF SOME
ACCAS CLOUDS IN THAT AREA PER 11-3.9 MICRON SATELLITE
IMAGERY...ESPECIALLY WITHIN CENTRAL/NORTHEAST KS. AS A
RESULT...WILL MAINTAIN 20 POPS THROUGH THE ENTIRE MORNING FOR
AREAS MAINLY SOUTH/SOUTHEAST OF A GENEVA-RED CLOUD-OSBORNE KS
LINE TO ACCOUNT FOR THIS OUTSIDE POSSIBILITY DESPITE LIMITED
LARGE-SCALE FORCING. OTHERWISE...THE VAST MAJORITY OF THE CWA
SHOULD REMAIN DRY UNDER GENERALLY MOSTLY CLEAR TO POSSIBLY PARTLY
CLOUDY SKIES.

THIS AFTERNOON/EVENING: IN MAINTAINING THEME FROM PREVIOUS
FORECAST...WILL KEEP ENTIRE CWA VOID OF SHOWER/STORM CHANCES
THROUGH THIS AFTERNOON AND EVENING...BUT JUST TO STRESS ONE MORE
TIME...THEY ARE NOT NECESSARILY "ZERO". AT LEAST FOR NOW
THOUGH...WILL RUN WITH THE ASSUMPTION THAT ANY MORNING ACTIVITY
FADES BY NOON...AND THAT ANY POSSIBLE LATE AFTERNOON ACTIVITY IN
WESTERN NEBRASKA STAYS AT LEAST SLIGHTLY WEST OF THE CWA. SKY-
COVER WISE...STILL EXPECT THE AFTERNOON/EVENING TO AVERAGE MOSTLY
CLEAR AS A WHOLE...BUT THERE COULD BE A FEW ENHANCED PATCHES OF
MID-UPPER CLOUDS ON A BRIEF BASIS. AT THE SURFACE...THE
DIURNALLY-DRIVEN PRESSURE FALLS FROM THE TROUGH CENTERED TO THE
WEST OVER THE HIGH PLAINS...ALONG WITH A DIURNAL INCREASE IN
MIXING TO AROUND 850 MB OR SLIGHTLY HIGHER FOR MOST OF THE
CWA...SHOULD TEAM UP TO PROMOTE ANOTHER BREEZY DAY OUT OF THE
SOUTH. HOWEVER...IF ANYTHING THE LATEST MODELS/GUIDANCE HAVE
TRENDED DOWN A FEW MPH FROM PREVIOUS FCST...ESPECIALLY WITHIN THE
WESTERN 1/2 OF THE CWA. AS A RESULT...WILL RUN WITH AFTERNOON
SUSTAINED SPEEDS OF GENERALLY NO MORE THAN 15-20 MPH IN
EASTERN/SOUTHERN ZONES...AND MORE-SO 10-15 MPH IN WESTERN/NORTHERN
COUNTIES...WITH GUSTS OF COURSE AT LEAST 5 MPH HIGHER THAN
SUSTAINED. TEMP-WISE...WITH HINTS OF VERY SLIGHT WARMING AT THE
850MB LEVEL COMPARED TO YESTERDAY...SEE LITTLE REASON WHY MOST
PLACES SHOULDN`T RISE A FEW DEGREES HIGHER...ESPECIALLY IN THE
WESTERN 1/2. WILL AIM FOR HIGHS RANGING FROM LOW-90S
EAST...MID-90S CENTRAL AND MID-UPPER 90S WEST AND SOUTHWEST.
ALTHOUGH THIS WILL PROMOTE RATHER UNCOMFORTABLE HEAT INDEX VALUES
INTO THE MID-UPPER 90S THANKS TO DEWPOINTS WELL INTO THE 60S MOST
AREAS...AT LEAST THEY SHOULD SAFELY FALL SHORT OF THE MORE
DANGEROUS 100+ DEGREES VALUES.

LATE TONIGHT (POST-MIDNIGHT): OVERALL LITTLE CHANGE IN THE LARGE-
SCALE MID-UPPER LEVEL SCENE THAN RIGHT NOW...AS THE LOCAL AREA
REMAINS UNDER WEST-SOUTHWEST FLOW ALOFT...ALONG THE NORTHERN EDGES
OF A SOUTHERN PLAINS RIDGE...AND WELL-SOUTHEAST OF THE LARGE
TROUGH WAY OFF TO THE NORTHWEST...OF WHICH THE MAIN VORT MAX WILL
JUST BE IMPINGING ON THE FAR NORTHWEST CONUS BY SUNRISE THURSDAY.
CERTAINTLY THE MAJORITY OF THE CWA SHOULD AGAIN REMAIN DRY UNDER
MOSTLY CLEAR SKIES AND IN THE PRESENCE OF STEADY SOUTH BREEZES AS
HIGH AS 10 TO POSSIBLY 15 MPH. HOWEVER...WITH THE EXIT REGION OF A
DECENT 30-40 KNOT SOUTHWESTERLY LOW LEVEL JET LIKELY TO BE SETTING
UP NEAR THE EASTERN/SOUTHEAST FRINGES OF THE CWA LATE IN THE
NIGHT...JUST CANNOT RULE OUT A FEW ISOLATED SHOWERS/STORMS GETTING
GOING AND AFFECTING PRIMARILY SOUTHEAST ZONES. THIS POSSIBILITY IS
HINTED AT IN MODELS SUCH AS THE 00Z GFS/GEM AND ALSO THE 00Z EMC
4KM WRF-NMM SIMULATED REFLECTIVITY. SO...CONSIDERING THERE IS AT
LEAST LIMITED SUPPORT FOR A SLIGHT CHANCE POP PER THESE
MODELS...AND ALSO GIVEN THAT THE PREVIOUS FORECAST ALREADY HAD
SLIGHT CHANCES GOING...OPTED TO MAINTAIN A 20 POP (SLIGHT CHANCE)
OF SHOWERS/NON-SEVERE STORMS FOR MUCH THE SAME AREA AS THIS
MORNING`S CHANCE...SOUTHEAST OF A YORK-RED CLOUD-OSBORNE LINE.
TEMPERATURE-WISE...MADE VERY LITTLE CHANGE TO LOWS WHICH SHOULD
ALSO BE QUITE SIMILAR TO THOSE OF THIS MORNING...WITH MOST PLACES
RIGHT AROUND 70...EXCEPT COOLER MID-60S IN WEST-CENTRAL/NORTHWEST
ZONES. PLEASE NOTE THAT ALTHOUGH SOMEWHAT SURPRISING...LOWS BOTH THIS
MORNING AND AGAIN TOMORROW MORNING SHOULD FALL SHORT OF RECORD
WARM LOWS BY 2-4 DEGREES AT GRAND ISLAND/HASTINGS.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 425 AM CDT WED SEP 2 2015

THERE WILL BE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS AT
LEAST SOME PORTION OF OUR FORECAST AREA EVERY DAY. HOWEVER...THE
PRECIPITATION CHANCES WILL BE LOW AT GENERALLY 15 TO 20 PERCENT WITH
THE DRY WEATHER MORE THAN LIKELY CONTINUING FOR MOST AREAS.
TEMPERATURES WILL ALSO BE WELL ABOVE NORMAL THROUGH SUNDAY WITH
HIGHS IN THE UPPER 80S TO MID 90S. NORMAL HIGHS FOR THIS TIME OF
YEAR RANGE FROM THE LOWER 80S IN SOUTHERN NEBRASKA TO THE MID 80S IN
NORTHERN KANSAS. NORMAL LOWS ARE RIGHT AROUND 60...BUT WE CAN EXPECT
LOWS RIGHT AROUND 70 THROUGH SUNDAY MORNING. COOLER WEATHER WILL
MOVE IN BEHIND A COLD FRONT MONDAY INTO TUESDAY.

THURSDAY THROUGH SUNDAY...THE OVERALL PATTERN DOES NOT CHANGE VERY
MUCH WITH A LARGE UPPER TROUGH OVER THE PACIFIC NORTHWEST MID TO
LATE WEEK THAT WILL GRADUALLY SLIDE INTO THE NORTHERN HIGH PLAINS BY
SUNDAY. AT THE SAME TIME THERE WILL BE A PERSISTENT UPPER RIDGE OVER
THE EASTERN CONUS. CONSEQUENTLY...WE CAN EXPECT CONTINUED WARM
SOUTHERLY FLOW KEEPING OUR TEMPERATURES 5 TO 10 DEGREES ABOVE
NORMAL. A WEAK SHORT WAVE WILL SLIDE NORTHEAST ACROSS THE HIGH
PLAINS AROUND THE PERIPHERY OF THE LARGER SCALE WESTERN TROUGH. THIS
WILL LEAD TO A SLIGHT CHANCE OF HIGH PLAINS THUNDERSTORMS POSSIBLY
MAKING IT INTO OUR WESTERN ZONES THURSDAY EVENING/NIGHT. WEAK SHORT
WAVES WHICH ARE DIFFICULT TO FORECAST/TRACK SHOULD CONTINUE TO
TRAVERSE FROM SOUTHWEST TO NORTHEAST BETWEEN THE LARGER UPPER
FEATURES FRIDAY AND SATURDAY...WITH THE PRIMARY UPPER TROUGH
SWINGING OUT ON SUNDAY. FORCING ACROSS OUR AREA WILL BE WEAK WITH
THE WAVE/WAVES LARGELY TRACKING NORTHWEST OF OUR FORECAST AREA. THE
REALITY IS THAT MOST AREAS WILL PROBABLY REMAIN DRY THROUGH THIS
PERIOD WITH ONLY SMALL CHANCES OF PRECIPITATION.

SUNDAY NIGHT INTO TUESDAY...A PATTERN CHANGE IS EXPECTED WITH A
RATHER STRONG COLD FRONT MOVING THROUGH IN THE SUNDAY NIGHT/MONDAY
TIME FRAME. THIS WILL KNOCK A GOOD 10 DEGREES OFF OF OUR
TEMPERATURES AND MAYBE EVEN A LITTLE MORE. SHOWERS AND THUNDERSTORMS
WILL BE POSSIBLE NEAR THE FRONT AND THIS FRONT MAY STALL OUT JUST TO
OUR SOUTH AND THEN MEANDER BACK INTO OUR FORECAST AREA LEADING TO
CONTINUED CHANCES OF SHOWERS AND THUNDERSTORMS.

&&

.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1258 AM CDT WED SEP 2 2015

CONFIDENCE REMAINS HIGH IN VFR CEILING/VISIBILITY THROUGH THE
PERIOD...WITH ONLY A LIMITED COVERAGE OF HIGH AND POSSIBLY MID
CLOUDS FROM TIME TO TIME. ALTHOUGH THE RISK OF A BRIEF
SHOWER/THUNDERSTORM IS NOT TRULY "ZERO"...IT IS FAR TOO LOW TO
JUSTIFY EVEN A "VICINITY" MENTION. THAT LEAVES LOW LEVEL WIND
SHEAR (LLWS) AS THE MAIN ISSUE...THROUGH BOTH THESE FIRST FEW
HOURS EARLY THIS MORNING...AND THEN POSSIBLY AGAIN TOWARD THE END
OF THE PERIOD WEDNESDAY NIGHT. FOR NOW...WILL NOT INSERT ANY LLWS
CONCERNS FOR LATE IN THE PERIOD AND WILL DEFER TO LATER TAF
ISSUANCES TO ADDRESS.

HOWEVER...FOR THE ONGOING/IMMINENT ROUND OF LLWS THIS
MORNING...WILL MAINTAIN 5 HOURS OF FORMAL MENTION AT KGRI THROUGH
11Z...AS WINDS WITHIN THE LOWEST 1000 FT AGL QUICKLY ACCELERATE
TO AROUND 40KT FROM THE SOUTH-SOUTHWEST...CREATING ROUGHLY 30-35
KNOTS OF BULK SHEAR DIFFERENCE BETWEEN THE SURFACE AND THIS LEVEL.
HOWEVER...AT KEAR...HAVE REMOVED ANY MENTION OF LLWS AS THIS SITE
APPEARS TO BE JUST FAR ENOUGH WEST TO LARGELY KEEP OVERALL-BULK
SHEAR IN THE LOWEST 1000 FT BELOW 30KT.

AS FOR SURFACE WIND...BOTH THIS MORNING AND AGAIN THIS EVENING
SHOULD SEE SOUTHERLY WIND SPEEDS ONLY AROUND 10KT...ALTHOUGH THE
AFTERNOON HOURS WILL SEE INCREASED SPEEDS WITH GUST POTENTIAL UP
TO AROUND 20KT.

&&

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

$$

SHORT TERM...PFANNKUCH
LONG TERM...WESELY
AVIATION...PFANNKUCH



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