Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 011053
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
553 AM CDT FRI MAY 1 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 452 AM CDT FRI MAY 1 2015

BIGGEST ISSUE WILL BE DETERMINING CHANCES OF RAIN/THUNDER AND SKY
COVER.

SYNOPTIC FLOW IS ZONAL AND LOW-AMPLITUDE AS A FRONTOLYTIC COLD FRONT
TRIES TO PUSH EAST INTO THE AREA. THIS FRONT/TROUGH IS HAVING A HARD
TIME MAKING HEADWAY EAST. INSTABILITY IS QUITE LIMITED...ALTHOUGH
THERE IS A BIT OF AN UPPER LEVEL JET STREAK NEAR 50 KTS OR
SO...WHICH COULD HELP KICK UP SOME ISOLATED
THUNDERSTORMS...ESPECIALLY ON THE NEBRASKA SIDE OF THE CWA. A LOW-
AMPLITUDE WAVE COULD HELP KICK UP SOME SHOWERS/ISOLATED STORMS
TODAY...AND ANOTHER ONE TONIGHT COULD DO THIS AS WELL. CONFIDENCE IS
NOT HIGH...BUT SHORT TERM MODELS ALL INDICATE SOME HIT OR MISS TYPE
SHOWER/THUNDERSHOWER ACTIVITY FOR TODAY/TONIGHT.

FOR TEMPERATURES...WENT WITH HIRES ARW EAST WAS USED...AND I LIKED
SUPERBLEND FOR LOWS. SKY COVER WILL BE A TOUGH ONE AS PLENTY OF MID-
HIGH LEVEL SKY COVER COULD EXIST FOR MUCH OF THE DAY...BUT BREAKS IN
SKY COVER COULD HELP GET HIGHS INTO THE MID 70S...AND MAYBE A BIT
WARMER PERHAPS IN OUR SOUTHEAST. SOUNDINGS GENERALLY SUGGEST THAT WE
WILL BE MORE CLOUDY TONIGHT AS OPPOSED TO TODAY...BUT IT IS
CERTAINLY DIFFICULT TO IGNORE THE SHIELD OF CIRRUS THAT IS AFFECTING
MOST OF OUR CWA THIS MORNING AND THE UPPER LEVEL JET MAX COULD HELP
PERPETUATE THIS SHIELD.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 452 AM CDT FRI MAY 1 2015

PRIMARY FORECAST CONCERN REVOLVES AROUND MULTIPLE THUNDERSTORM
CHANCES.

THE LONG TERM PERIOD START OFF WITH MODELS IN GOOD AGREEMENT SHOWING
GENERALLY ZONAL FLOW IN PLACE IN THE UPPER LEVELS...WITH WEAK HIGH
PRESSURE OVER THE SOUTH CENTRAL CONUS...AND WEAK DISTURBANCE IN THE
MAIN FLOW...WHILE A STRONGER DISTURBANCE IN MOVING ACROSS WRN
PORTIONS OF CANADA. ONE OF THESE WEAKER DISTURBANCE IS EXPECTED TO
BE IN THE AREA SATURDAY MORNING...BUT ON ITS WAY OFF TO THE EAST
ALONG WITH A WEAKENING AND VEERING LLJ AXIS. KEPT THE INHERITED DRY
FORECAST IN PLACE...ANY ACTIVITY FROM THE FRIDAY NIGHT THAT MAY
LINGER INTO THIS PERIOD WOULD LIKELY BE IN THE FAR ERN PORTIONS OF
THE CWA FOR THE FIRST HOUR OR TWO. JUST NOT ENOUGH CONFIDENCE IN THE
TIMING BEING SLOWER TO CARRY ANY LINGERING POPS INTO THE POST 12Z
SATURDAY PERIOD. THE FORECAST FOR THE REST OF THE DAY SATURDAY AND
INTO SATURDAY NIGHT REMAIN DRY...A FEW MODELS TRY TO SPARK OFF SOME
WIDELY SCATTERED QPF IN A WEAKLY FORCED REGIME...CONFIDENCE IS TOO
LOW AT THIS POINT TO REINSERT ANY POPS. AS FAR AS TEMPERATURES
GO...CONTINUE TO SEE WARMER AIR ALOFT WORKING INTO ESP WRN PORTIONS
OF THE CWA...AND ALONG WITH GOOD SRLY LL FLOW...ABOVE AVERAGE HIGHS
OF UPPER 70S/LOW 80S ARE FORECAST.

AS WE GET INTO SUNDAY...FOCUS TURNS TO THAT ABOVE MENTIONED UPPER
LEVEL DISTURBANCE OVER WRN CANADA...WHICH DURING THE DAYTIME HOURS
MODELS CONTINUE TO SHOW SLIDING EAST NEAR THE US/CAN BORDER...AS
WELL AS ANOTHER PIECE OF SHORTWAVE ENERGY MOVING THROUGH THE ROCKIES
OUT AHEAD OF A LOW PRESSURE SYSTEM APPROACHING THE SWRN CAL COAST.
DURING THE DAYTIME HOURS...THAT NRN STREAM DISTURBANCE WILL PUSH A
SFC COLD FRONT SOUTH...WITH MODELS NOT IN TOO BAD OF AGREEMENT
SHOWING ITS LOCATION BY LATE AFTERNOON IN A SW/NE ORIENTATION
THROUGH THE CWA /THERE ARE SOME VARIATIONS WITH HOW FAR S IT GETS BY
00Z/. AS WE GET INTO THE EVENING/OVERNIGHT HOURS...LIFT INCREASES
WITH AID FROM THAT W/SWRN WAVE AS WELL AS WITH AN INCREASED S/SWRLY
LLJ...WITH THUNDERSTORM DEVELOPMENT EXPECTED ALONG/NEAR THAT SFC
FRONT. AHEAD OF THE FRONT...DID BUMP UP TEMPS A BIT...MODELS SUGGEST
850MB TEMPS WITHIN A FEW DEGREES OF 20C...AND THINKING IS THAT WITH
BETTER MIXING AHEAD OF THE FRONT THAT LOWER/MID 80S NOT OUT OF THE
QUESTION. DEWPOINTS LOOK TO CLIMB BACK INTO THE 50S. MODEST MUCAPE
VALUES ARE EXPECTED TO DEVELOP /NOT QUITE BUYING INTO THE NOTABLY
HIGHER VALUES SHOWN BY THE NAM/. OVERALL DEEP LAYER SHEAR IS NOT ON
THE IMPRESSIVE SIDE...WITH MODELS GENERALLY IN THE 20-30KT
RANGE...BUT IS ENOUGH THAT AT LEAST A FEW STRONG/SEVERE
THUNDERSTORMS CANT BE RULED OUT...AND WILL INSERT A MENTION IN THE
HWO.

LOOKING TO THE NEXT WORK WEEK...THE UNSETTLED PATTERN IS EXPECTED TO
CONTINUE...WITH MULTIPLE THUNDERSTORM CHANCES IN THE FORECAST.
OUTSIDE OF SOME MINOR ADJUSTMENTS...WENT WITH WHAT CR
INIT/SUPERBLEND SHOWED FOR POPS. MONDAY...MODELS SHOW THAT UPPER
LEVEL SYSTEM OFF THE SRN WEST COAST MOVING INLAND...BY EVENING IS
MOVING INTO AZ. SHORTWAVE ENERGY EJECTED OUT AHEAD OF THAT LOW WILL
BRING ADDITIONAL PRECIP CHANCES TO THE CWA...THOUGH SOME UNCERTAINTY
EXISTS...AS HOW MUCH OF THE CWA IS AFFECTED IS GOING TO BE DRIVEN BY
WHERE EXACTLY THAT SFC FRONT THAT MOVED THROUGH SUNDAY ENDS UP.
GENERAL STORY FROM MODELS IS THAT THE FRONT MAY BE RUNNING THROUGH
SRN PORTIONS OF THE CWA...AND THATS WHERE THE HIGHER POPS REMAIN.

DURING THE TUE/WED/THURS TIME FRAME...THAT SYSTEM PUSHES FURTHER
E/NE...WITH MODELS SHOWING THE MID/UPPER LEVEL PATTERN FILLING TO AN
OPEN WAVE...POSSIBLY DEVELOPING INTO ANOTHER CLOSED CIRCULATION AS
IT MOVES THROUGH THE ROCKIES. UNCERTAINTY WITH THE EVOLUTION OF THE
DISTURBANCE LIES WITH ITS INTERACTION/PHASING IN WITH A STRONGER LOW
PRESSURE SYSTEM MOVING TOWARD THE WEST COAST...THOUGH EVEN WITH
MODEL DIFFERENCES IN THE STRONGER LOWS TRACK...THAT SHORTWAVE TROUGH
/AT THIS POINT/ LOOKS TO MAKE ITS MAIN SWING THROUGH THE REGION AT
SOME POINT WED/WED NIGHT. TOO EARLY AT THIS POINT TO START NAILING
DOWN SPECIFICS IN REGARD TO SEVERE WEATHER CHANCES...BUT IT IS A
PERIOD THAT BEARS WATCHING IN THE COMING DAYS.

REGARDING TEMPS MON THROUGH THURS...DIDNT STRAY FROM THE CR
INIT/SUPERBLEND...WHICH KEEPS HIGHS IN THE 60S/70S EARLY ON TO
WIDESPREAD MID 70S BY THURSDAY.

&&

.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 551 AM CDT FRI MAY 1 2015

BIGGEST ISSUE AGAIN IS WIND SHEAR...FOR EARLY THIS MORNING AND
AGAIN TONIGHT. THE LEVEL MAY BE A BIT HIGHER TONIGHT AT 1200 FT
AND INTRODUCING THIS BEFORE 06Z. SHOWERS COULD BE AROUND AT ANY
TIME AND ISOLATED THUNDER IS NOT OUT OF THE QUESTION...HOWEVER THE
LIKELIHOOD OF THUNDER IS LOW ENOUGH TO LEAVE OUT OF THE FORECAST.

&&

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

$$

SHORT TERM...HEINLEIN
LONG TERM...ADP
AVIATION...HEINLEIN



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