Area Forecast Discussion
Issued by NWS Hastings, NE

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000
FXUS63 KGID 121808
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
108 PM CDT SAT APR 12 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 451 AM CDT SAT APR 12 2014

MAIN FOCUS WILL BE ON CHANCES OF SEVERE THUNDERSTORMS MAINLY TONIGHT
AND ALSO CHANCES OF PRECIPITATION.

SYNOPTICALLY...WE WILL BE WITHIN SOUTHWEST FLOW ALOFT IN ADVANCE OF
AN APPROACHING TROUGH ENTERING THE ROCKIES AND MAKING IT INTO THE
HIGH PLAINS BY LATE TONIGHT. A SURFACE COLD FRONT JUST TO THE
NORTHWEST OF THE CWA CONTINUES TO MOVE SOUTHEAST THIS MORNING AS A
STRONG LOW-LEVEL JET OUT AHEAD OF IT CONTINUES TO KEEP OUR OVERNIGHT
TEMPERATURES QUITE MILD. FOR REFERENCE...AT 4 AM...HASTINGS WAS 62.
HIGH TEMPERATURES SHOULD HAVE NO PROBLEM MAKING THE MID 70S TO NEAR
80 FOR MOST OF THE CWA. ALTHOUGH A COLD FRONT IS SLICING THROUGH THE
CWA TODAY...COLDER AIR LAGS WELL TO THE NORTH. A SURFACE LOW IN
SOUTHEASTERN COLORADO IS FORECAST TO PULL TO THE EAST INTO
SOUTHWESTERN KANSAS WITH A DRY LINE EXTENDING SOUTH OF IT. BY
00Z...THE LOW WILL HOOK UP WITH THE AFOREMENTIONED COLD FRONT AND
ESSENTIALLY HELP STALL THE FRONT FOR A WHILE. THIS FRONT WILL LIKELY
STILL BE IN THE FAR SOUTHERN CWA AND PERHAPS EXTENDING INTO THE FOR
EASTERN CWA AS WELL. A SOLID CAP SHOULD KEEP CONVECTION FROM FIRING
BEFORE 00Z...BUT INCLUDED A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS LATE THIS AFTERNOON IN THE FAR EAST/SOUTH JUST IN CASE
THE CAP DECIDES TO BUST OPEN A LITTLE EARLY. INSTABILITY WILL BE IN
THE 1500 TO 2200 J/KG RANGE FOR THE NIGHT...BUT WILL DECREASE
CONSIDERABLY AFTER MIDNIGHT AND WILL BE PRIMARILY ELEVATED. BULK
SHEAR WILL BE GREAT ENOUGH TO SUSTAIN AT LEAST MINIMAL SEVERE
WEATHER...GENERALLY IN THE 35 TO 50 KT RANGE. THE FAR SOUTHERN CWA
WILL HOLD ON TO HIGHER MUCAPES THE LONGEST AND WILL BE AN AREA TO
WATCH FOR HAIL BIGGER THAN QUARTERS AND COULD PERHAPS GET CLOSER TO
GOLF BALLS DEPENDING ON TIMING OF INITIATION OF STORMS. THE CHANCE
OF SHOWERS AND THUNDERSTORMS SPREADS NORTH AS THE NIGHT PROGRESSES
WITH MOISTURE SPREADING NORTH OF THE FRONT. MUCAPES WIND DOWN FROM
NORTH TO SOUTH OVERNIGHT. WE COULD VERY WELL BE DEALING WITH SEVERE
WEATHER AFTER MIDNIGHT TONIGHT IN OUR SOUTHERN CWA...WITH LARGE HAIL
AND STRONG WIND BEING THE PRIMARY THREATS...SINCE THESE STORMS WILL
BE ELEVATED. LOW TEMPERATURES WILL BE TRICKY...BUT I WILL GO WARMER
THAN GUIDANCE VALUES AS MOST NUMERICAL SOLUTIONS HAVE TRENDED
WARMER.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 451 AM CDT SAT APR 12 2014

MULTI-DAY 500 MB MEANS FROM THE GFS/EC ENSEMBLE MEANS HAVE THE
LONGWAVE TROF OVER THE CNTRL USA THRU FRI 4/18...WITH RIDGES ALONG
THE W COAST AND OVER THE WRN ATLANTIC. THIS MEANS TEMPS WILL AVERAGE
COOLER THAN NORMAL...BUT THIS NOT WITHOUT SOME RECOVERY BACK TO NEAR
NORMAL ON INDIVIDUAL DAYS. MUCH COOLER THAN NORMAL TEMPS WILL OCCUR
SUN-MON...FOLLOWED BY A RETURN TO NEAR NORMAL BY WED. TEMPS
TAKE A HIT THU THEN BACK TO NEAR NORMAL FRI.

ALOFT: THE REGION WILL BE UNDER SW FLOW SUN. A SHORTWAVE TROF WILL
BE ADVANCING THRU THE SRN PLAINS. MEANWHILE...A STRONGER TROF WILL
BE DIVING THRU THE INTERMOUNTAIN W. ADDITIONAL HEIGHT FALLS WILL
OCCUR OVER THE NRN PLAINS SUN NIGHT...AND THE POSITIVE TILT PHASED
TROF WILL SWING THRU MON. A SHORTWAVE RIDGE ARRIVES LATE TUE...AHEAD
OF THE NEXT TROF WHICH FOLLOWS WED. THU-FRI WNW FLOW.

SURFACE: AT DAYBREAK SUN...A STRONG COLD FRONT WILL EXTEND FROM THE
GREAT LAKES-KANSAS CITY-OK PANHANDLE WITH A LOW OVER CNTRL KS. THIS
FRONT WILL SURGE FURTHER S OF THE FCST AREA AS STRONG AND CHILLY
CANADIAN HIGH PRES BEGINS EXERTING ITS INFLUENCE. THIS HIGH WILL
PASS THRU MON NIGHT. A CLIPPER TYPE LOW WILL RACE SE INTO MT TUE AND
INTO IA WED...WITH ITS COLD FRONT CROSSING THE REGION WED. ANOTHER
CHILLY CANADIAN HIGH BUILDS IN THU. A LEE SIDE TROF AND RETURN FLOW
WILL DEVELOP FRI.

HAZARDS: SCT TSTMS POSSIBLE SUN MRNG MAINLY S OF HWY 6. SOME COULD
BE STRONG OVER N-CNTRL KS. A WIND ADVISORY LOOKS ALMOST CERTAIN FOR
MOST OF THE FCST AREA SUN FOR SUSTAINED WINDS OF 30-39 MPH AND GUSTS
ABOVE 45. THERE IS ALSO CHANCE /LESS THAN 50%/ FOR A SWATH OF 1-4"
ALONG AND N OF A LINE FROM LEXINGTON-COLUMBUS. THE PROBABILITIES FOR
THE UPPER PORTION OF THAT RANGE ARE EVEN LOWER. THE PRECIP TYPE IS
THE LOWEST CONFIDENCE PORTION OF THIS FCST. SEE BELOW FOR MORE ON
THIS.

THE DAILY DETAILS...

MOST OF THE FCST EFFORT WAS SPENT ON SUN-MON. VERY LITTLE WAS
CHANGED TUE-FRI.

SUN: MULTIPLE CLUSTERS OF ELEVATED TSTMS WILL BE IN PROGRESS AND/OR
DEVELOPING OVER OR NEARBY THE FCST AREA AT DAWN...DUE TO WAA
ASSOCIATED WITH DYNAMIC/MASS ADJUSTMENTS FROM THE APPROACHING TROF
AND THE ASSOCIATED COUPLED UPPER-LEVEL ET STREAKS. EXACTLY WHERE IS
LESS CERTAIN...BUT 850 MB DEWPOINTS UP TO 10C WILL BE ROTATING
CYCLONICALLY WESTWARD ALONG THE NEB-KS BORDER. SO THE BEST CHANCE
WILL BE S AND E OF THE TRI-CITIES. THE POTENTIAL ELEVATED TSTM
CLUSTERS WILL PERSIST THRU THE MORNING. 03Z SREF HAS MUCAPE 500-1000
J/KG UNTIL 11AM. 1-6KM SHEAR OF 30-40 KTS WILL STILL BE SUPPORTIVE
OF STRONG STORMS....PRIMARILY OVER N-CNTRL KS WHERE CAPE WILL BE
HIGHEST.

IN THE IN MEANTIME DEFORMATION ZONE RAINBAND WILL BE ORGANIZING
FURTHER TO THE NW AND WILL SWEEP FROM W-E ACROSS MOST OF S-CNTRL NEB
DURING THE DAYTIME HOURS. THE TEMP PROFILE WILL BE COOLING. SO THE
RAIN COULD MIX WITH OR CHANGE TO SNOW BRIEFLY BEFORE ENDING. THIS
SITUATION LOOKS SIMILAR TO APR 3RD...WHEN ONLY THE BOUNDARY LAYER
WAS ABOVE FRZG. THIS MEANS THE INTENSITY OF PRECIP WILL BE A FACTOR
IN ANY POSSIBLE CHANGEOVER. THE 18Z NAM BUFKIT TIME-HEIGHT CROSS
SECTION FOR ORD SUGGEST THE STRONGEST LIFT WILL OCCUR PRIOR TO
CHANGEOVER. THE 00Z CAME IN WITH MORE SUFFICIENT LIFT POST
CHANGEOVER TO ALLOW FOR SOME WET ACCUM.

GIVEN THE MARGINAL TEMP PROFILE...THE PRECIP TYPE AND ANY POSSIBLE
SNOW ACCUM IS VERY LOW CONFIDENCE. IN THESE SITUATIONS...WE MAY NOT
KNOW WHAT WILL HAPPEN UNTIL IT ACTUALLY OCCURS. JUST BE PREPARED FOR
THE POSSIBILITY THAT FUTURE FCSTS COULD CONTAIN SOME MEASURABLE
SNOWFALL WITH THE GREATEST CHANCE N AND W OF THE TRI-CITIES.

WIND: STRONG CAA WILL BE UNDERWAY AT DAYBREAK. THE PRES GRADIENT
WILL BE ROUGHLY 25 MB ACROSS NEB. PAST EVENTS HAVE SHOWN THAT
USUALLY A 15 MB GRADIENT IS SUFFICIENT FOR A MARGINAL WIND ADVISORY.
PEAK PRES RISES WILL BE 7-10 MB IN 6 HRS OVER S-CNTRL NEB AND 10-12
MB OVER N-CNTRL KS. GUSTS OF 45-55 MPH APPEAR LIKELY.

DAYTIME HIGH TEMPS WILL OCCUR AT SUNRISE. TEMPS WILL THEN CONTINUE
TO FALL THRU THE DAY.

RAIN/SNOW SHOULD BE DONE FOR THE MOST PART BY SUNSET.

MON: VERY CHILLY AND BLUSTERY. MULTI-MODEL CROSS SECTIONS SUGGEST
THE DAY STARTS CLOUDY WITH THE UPPER TROF REMAINING TO THE W. THE
FCST DOES NOT HAVE THE HIGHER AMOUNT OF CLOUD COVER I PREFER...EVEN
INTO THE AFTERNOON. MID-HIGH CLOUDS WILL CLEAR OUT...BUT WIDESPREAD
STRATOCU WILL DEVELOP WITH THE COLD AIR ALOFT.

850 MB TEMPS 2 STANDARD DEVIATIONS BELOW NORMAL. USED THE GEM 2M
TEMPS WHICH HAS 41-47F. NO RECORDS WILL BE THREATENED...BUT MON WILL
GO DOWN AS ONE OF THE TOP 10 COOLEST ON RECORD FOR APR 14TH.

NNW WINDS GUSTING 25-35 MPH WILL MAKE IT FEEL EVEN COLDER.

TUE: BREEZY WITH SW WINDS GUSTING 20-30 MPH. MUCH WARMER WITH TEMPS
FALLING JUST SHORT OF NORMAL. SOME INCREASE IN MID-HIGH CLOUDS IN
THE AFTERNOON.

WED: LATE DAY COLD FRONTAL PASSAGE. SKIES PROBABLY END UP MOSTLY
CLOUDY...BUT THE FCST IS MORE OPTIMISTIC AT PARTLY CLOUDY. CLOUDS
WILL NEED TO BE INCREASED WITH LATER FCSTS. TEMPS SHOULD STILL
MANAGE NEAR NORMAL.

BELIEVE THE MENTION OF SHWRS IS TOO BROAD IN THE THU-FRI TIME FRAME
DUE TO UNCERTAINTY IN THE MODELS. OVERALL...A BIG COOL DOWN THU.
THERE WILL BE A THREAT OF LIGHT SHWRS...BUT PRECIP AMOUNTS WILL BE
MINOR WHERE THEY DO OCCUR.

FRI: UNCERTAINTY AS SOME MODELS TRY TO CLOSE OFF AN UPPER LOW
SOMEWHERE OVER THE CNTRL USA.

&&

.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 107 PM CDT SAT APR 12 2014

THE MAIN HIGHLIGHTS OF THIS TAF PERIOD INCLUDE INCREASING CHANCES
FOR SHOWERS/THUNDERSTORMS ESPECIALLY DURING THE FINAL 6
HOURS...ALONG WITH A NOTABLE INCREASE IN NORTHERLY WIND SPEEDS
DURING THE FINAL 12 HOURS. ALTHOUGH CONFIDENCE REMAINS QUITE HIGH
IN VFR CEILING/VISIBILITY THROUGH AT LEAST THE FIRST 15 HOURS INTO
LATE TONIGHT...THE LATTER 9 HOURS OF THE PERIOD INTO SUNDAY
MORNING ARE FAIRLY LOW CONFIDENCE AND ARE PRONE TO PLENTY OF
ADJUSTMENTS. STARTING OFF THIS AFTERNOON INTO AT LEAST THE FIRST
PART OF TONIGHT...BREEZES WILL PREVAIL FROM A NORTH-NORTHEAST
DIRECTION WITH SUSTAINED SPEEDS GENERALLY UNDER 15KT AND ANY
CEILING WELL INTO VFR RANGE. THEN LATE TONIGHT INTO SUNDAY
MORNING...NORTH WINDS WILL STEADILY INCREASE...WITH GUST POTENTIAL
INCREASING TO AT LEAST 35KT THROUGH THE LAST SEVERAL HOURS OF THE
PERIOD. AS FOR PRECIPITATION/CEILINGS...ITS LOOKING INCREASINGLY
LIKELY THAT THERE IS VERY LITTLE RISK FOR SHOWERS/STORMS MUCH
BEFORE SUNRISE...WITH MUCH BETTER CHANCES COMING INTO PLAY FOR THE
LAST 3-6 HOURS OF THE PERIOD. GIVEN THAT THIS SHOWER/STORM CHANCE
IS STILL WELL INTO THE SECOND HALF OF THE TAF PERIOD...DID NOT
FEEL CONFIDENT ENOUGH TO ADVERTISE ANY TEMPO/PREVAILING GROUP FOR
PRECIPITATION YET...BUT INSTEAD HAVE A VICINITY THUNDERSTORM
(VCTS) IN PLACE STARTING AT 11Z.

&&

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

$$

SHORT TERM...HEINLEIN
LONG TERM...HALBLAUB
AVIATION...PFANNKUCH



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