Hail in Nebraska, April 24, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
559 PM CDT FRI APR 24 2009

.AVIATION...00Z KGRI TAF. THUNDERSTORMS ARE DEVELOPING THIS
EVENING ALONG THE COLD FRONT WELL SOUTH OF KGRI. THESE
THUNDERSTORMS WILL REMAIN SOUTH OF KGRI. HOWEVER...THERE IS A
SLIGHT CHANCE THAT THUNDERSTORMS WILL FORM FURTHER NORTH BEHIND
THE FRONT AFTER MIDNIGHT. THIS IS A LOW ENOUGH CHANCE TO KEEP IT
OUT OF THE KGRI TAF FOR NOW. TOMORROW WILL THEN BE A COOL...CLOUDY...AND
DRY DAY WELL BEHIND THE FRONT. CEILINGS WILL FOR THE MOST PART BE
VFR BUT COULD SLIDE INTO THE MVFR RANGE DURING THE MORNING HOURS.

&&

.PREV DISCUSSION... /ISSUED 347 PM CDT FRI APR 24 2009/

SHORT TERM...FOR TONIGHT THROUGH 12Z SUNDAY.

WATER VAPOR IMAGERY FROM THIS AFTERNOON REVEALS A POSITIVELY TILTED
UPPER TROUGH POSITIONED FROM THE HUDSON BAY REGION INTO THE
CALIFORNIA PACIFIC COAST AREA.  DOWNSTREAM FROM THIS TROUGH A WARM
AND CURRENTLY DRY SOUTHWEST FLOW REGIME IS IN PLACE ACROSS THE
PLAINS. ON A SMALLER SCALE...A SHORT WAVE CURRENTLY SEEN EXITING THE
CENTRAL ROCKIES IS BEGINNING TO SHOW SOME ENHANCEMENT/LIFT ACROSS
THE CENTRAL PLAINS.  THIS SHORT WAVE WILL BE KEY TO DETERMINING IF
CONVECTION DEVELOPS LATER THIS AFTERNOON TO EARLY EVENING. REGIONAL
SURFACE OBS DEPICT A SLOW MOVING COLD FRONT POSITIONED FROM EAST
CENTRAL NEBRASKA INTO NORTH CENTRAL KANSAS AND EAST CENTRAL COLORADO
WHILE A WEAK DRYLINE IS SEEN FROM A TRIPLE POINT NEAR SMITH CENTER
EXTENDING SOUTH TOWARD WICHITA AND HUTCHINSON. LAPS DATA CONTINUES
TO SHOW DECENT CAPPING HOLDING ALONG AND AHEAD OF THE FRONT/DRYLINE
ALTHOUGH 0-1KM ML CAPES OF 800-1200 J/KG ARE IN PLACE AHEAD OF THESE
BOUNDARIES.

THE MAIN QUESTION AT HAND FOR LATE THIS AFTERNOON TO EARLY
EVENING...IS IF THE AFOREMENTIONED SHORT WAVE CAN HELP WEAKEN THE
CAP ENOUGH FOR CONVECTION TO FORM. THE 18Z NAM CONTINUES TO SHOW A
SMALL RIBBON OF WEAK INHIBITION DEVELOPING ALONG THE FRONT BY 00Z.
THIS CONTINUES TO SUPPORT THE IDEA SOME ISOLATED CONVECTION MAY FORM
NEAR THE TRIPLE POINT AND EASTWARD ALONG THE FRONT BY LATE AFTERNOON
TO EARLY EVENING.  ALTHOUGH LCL HEIGHTS WILL REMAIN HIGH VIA A VERY
WELL MIXED BOUNDARY LAYER...THE DEEP LAYER SHEAR IS STILL FORECAST
TO INCREASE TO AROUND 30 TO 35 KNOTS WOULD SUPPORT HIGH BASED
SUPERCELLS WITH A LARGE HAIL THREAT VERY POSSIBLE.  THE SHIP
PARAMETER OFF THE 12Z NAM CONTINUES TO SHOW VALUES OVER 1 TO 2 WHICH
POTENTIALLY SUPPORTS HAIL UP TO TENNIS BALL SIZE.  ALL OF THIS SETS
THE STAGE FOR AT LEAST AN ISOLATED THREAT FOR SEVERE CONVECTION
THROUGH MID EVENING SOUTH OF A HEBRON TO STOCKTON LINE. AS THE
EVENING GIVES WAY TO THE OVERNIGHT HOURS...ANY STRONGER CONVECTION
IS SHOWN TO SLIP EAST OF THE AREA WHILE SOME WEAK ELEVATED
CONVECTION LOOKS POSSIBLE BEHIND THE FRONT AS IT BEGINS TO PUSH
FURTHER SOUTH INTO CENTRAL KANSAS.

SATURDAY IS THEN SHAPING UP TO BE MUCH QUIETER THAN ORIGINALLY
THOUGHT AS THE FRONT MOVES FAR ENOUGH SOUTH TO LEAVE ONLY A SLIGHT
CHANCE FOR THUNDERSTORMS ACROSS THE FAR SOUTHEASTERN CWA THROUGH THE
DAY. OTHERWISE...A CLOUDY AND MUCH COOLER DAY WILL PREVAIL WITH
HIGHS IN THE 50S. HOWEVER...ATTENTION THEN SHIFTS TO SATURDAY
NIGHT AS THE MODELS PUSH A SMALL BUT POTENT SHORT WAVE THROUGH THE
REGION DURING THE LATE EVENING TO OVERNIGHT HOURS. THIS ALONG WITH
A 50 TO 60 KT LLJ NOSING INTO THE AREA AND ELEVATED CAPE VALUES OF
500 TO 1000 J/KG...SHOULD SUPPORT AN MCS DEVELOPING OVER MOST OF
THE CWA. ADJUSTED POPS UP SLIGHTLY TO ACCOUNT FOR THIS PRECIP
POTENTIAL ALTHOUGH ONGOING FORECAST CAUGHT THIS TREND WELL.

LONG RANGE...SUNDAY THROUGH FRIDAY. THE PATTERN IN THE BIG
PICTURE REMAINS ON THE SAME PAGE AS YESTERDAY. ESSENTIALLY...
THE KANSAS/NEBRASKA REGION REMAINS IN A BROAD SOUTHWEST FLOW
THROUGH MOST OF THE WEEK AHEAD AS TROUGH OWNS THE WESTERN
HALF OF THE UNITED STATES.

FOR SUNDAY...EXPECT A ROUND OF SHOWERS/STORMS TO BE ONGOING
AS THE DAY BEGINS AND WORK NORTHEAST ACROSS THE AREA. SHARP
JET STREAK BOLTS RIGHT INTO THE CWFA LATE SATURDAY NIGHT AS
SHORTWAVE EJECTS ONTO THE PLAINS. HAVE KEPT THE HIGHEST RAIN
CHANCES OVER THE NORTHEAST CWFA...OR THE DIRECTION PRECIPITATION
WILL BE HEADED BY THEN. AS THINGS WRAP UP BY EARLY AFTERNOON...
MODELS DEPICT SOME CLEARING AND A REFORMATION OF THE COLD FRONT
OVER THE CWFA. NAM IS MUCH FURTHER WEST...LIKE WELL WEST OF THE
HIGHWAY 281 AND FIRES LATE DAY STORMS ON THE FRONT. THE GFS
IS FURTHER EAST...AROUND HIGHWAY 81 AND DOES THE SAME. UKMET
HIGHLIGHTS MORE THE FAR SOUTHEAST CWFA AS DOES THE NEW ECMWF.
MODERATE INSTABILITY WILL LIKELY EVOLVE BY LATE AFTERNOON...
AS SHEAR INCREASES. HAVE SPLIT THINGS...WITH BEST SHOT FOR
STORMS SOUTH/EAST OF HASTINGS. THAT IS OFTEN THE LOCATION
IN THESE TYPES OF SITUATION. A LOT WILL DEPEND UPON JUST
WHAT IS LEFT BEHIND BY MORNING CONVECTION...WHETHER WE CAN
CLEAR OUT AND SO FORTH.

MONDAY AND TUESDAY...THESE TWO DAYS LOOK MAINLY DRY FOR THE
CWFA AS SURFACE HIGH PRESSURE MOVES INTO THE AREA. TEMPERATURES
LOOK COOL. WEAK COLD ADVECTION OCCURS ON MONDAY WITH A NORTH
FLOW...WITH ONLY A SMALL REBOUND IN TEMPERATURES TUESDAY. BOTH
DAYS LOOK TO BE BELOW SEASONAL NORMALS IN GENERAL.

BEGINNING LATE TUESDAY NIGHT...MOISTURE RETURN WILL INCREASE
ACROSS THE CENTRAL PLAINS. WITHIN THE UPPER SOUTHWEST FLOW...
SHORT WAVE ENERGY STARTS SLIP NORTHEAST AND ACROSS THE AREA.
WILL KEEP SOME SMALL CHANCES FOR PRECIPITATION LATE TUESDAY
NIGHT INITIALLY...BUT THE BEST RISK FOR RAIN COMES WEDNESDAY NIGHT
AND THURSDAY WITH A MORE SUBSTANTIAL SHORTWAVE. AT THIS
JUNCTURE...HAVE KEPT THE BROAD BRUSH TYPE OF PRECIPITATION CHANCES
BUT EVEN THE LATEST ECMWF CONTINUES TO FAVOR THE WEDNESDAY
NIGHT/THURSDAY TIME WITH THE BEST CHANCE FOR PRECIPITATION.
TEMPERATURES SHOULD MODERATE WEDNESDAY AND THURSDAY BEFORE
COOLING OFF AGAIN FRIDAY/NEXT WEEKEND IN A POST FRONTAL REGIME.

&&

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

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE HASTINGS NE
342 PM CDT FRI APR 24 2009

KSZ005>007-017>019-NEZ077-085>087-251200-
PHILLIPS-SMITH-JEWELL-ROOKS-OSBORNE-MITCHELL-FILLMORE-WEBSTER-
NUCKOLLS-THAYER-
342 PM CDT FRI APR 24 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL KANSAS AND
PORTIONS OF SOUTH CENTRAL NEBRASKA GENERALLY ALONG AND SOUTH OF A
LINE FROM GENEVA NEBRASKA TO PHILLIPSBURG KANSAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

A SLIGHT THREAT OF SEVERE THUNDERSTORMS WILL EXIST LATE THIS
AFTERNOON TO EVENING OVER PORTIONS OF THE OUTLOOK AREA. THE
HIGHEST THREAT FOR SEVERE THUNDERSTORMS WILL EXIST AFTER 5 PM
THIS AFTERNOON ALONG AND SOUTH OF A HEBRON NEBRASKA TO STOCKTON
KANSAS LINE. VERY LARGE HAIL UP TO THE SIZE OF TENNIS BALLS AND
DAMAGING WINDS UP TO 60 MPH WILL BE POSSIBLE FROM ANY STORMS THAT
DO BECOME SEVERE OVER THIS AREA. IN ADDITION...A FEW STRONG STORMS
WILL ALSO BE CAPABLE AS FAR NORTH AS A GENEVA NEBRASKA TO
PHILLIPSBURG KANSAS LINE WITH LARGE HAIL UP TO NICKEL SIZE
POSSIBLE.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

THERE ARE PERIODIC CHANCES OF THUNDERSTORMS FROM SATURDAY THROUGH
THURSDAY. CONDITIONS ARE STARTING TO LOOK FAVORABLE FOR A FEW
STRONG TO SEVERE THUNDERSTORMS LATE SUNDAY AFTERNOON INTO SUNDAY
EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS WILL LIKELY BE NEEDED AFTER 5 PM THIS AFTERNOON AND
LASTING INTO THE EVENING...ESPECIALLY SOUTH OF A HEBRON TO
STOCKTON.

EMERGENCY MANAGERS...LAW ENFORCEMENT AND SPOTTER GROUPS SHOULD MAKE
PREPARATIONS NOW FOR QUICK DEPLOYMENT THIS AFTERNOON.

&&

MORE INFORMATION MAY BE OBTAINED AT THE FOLLOWING WEB PAGE:
   HTTP://WWW.WEATHER.GOV/HASTINGS  (ALL LOWERCASE)

NEZ039>041-046>049-060>064-072>076-082>084-251200-
VALLEY-GREELEY-NANCE-SHERMAN-HOWARD-MERRICK-POLK-DAWSON-BUFFALO-
HALL-HAMILTON-YORK-GOSPER-PHELPS-KEARNEY-ADAMS-CLAY-FURNAS-HARLAN-
FRANKLIN-
342 PM CDT FRI APR 24 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
NEBRASKA GENERALLY ALONG AND NORTH OF A LINE FROM GENEVA NEBRASKA
TO PHILLIPSBURG KANSAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

A CHANCE OF THUNDERSTORMS WILL EXIST LATER THIS EVENING AND
LASTING INTO TONIGHT. HOWEVER...WIDESPREAD STRONG TO SEVERE
THUNDERSTORMS ARE NOT ANTICIPATED FOR AREAS ALONG AND NORTH OF A
GENEVA TO PHILLIPSBURG LINE.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

THERE ARE PERIODIC CHANCES OF THUNDERSTORMS FROM SATURDAY THROUGH
THURSDAY. CONDITIONS ARE STARTING TO LOOK FAVORABLE FOR A FEW
STRONG TO SEVERE THUNDERSTORMS LATE SUNDAY AFTERNOON INTO SUNDAY
EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT.

&&

MORE INFORMATION MAY BE OBTAINED AT THE FOLLOWING WEB PAGE:
   HTTP://WWW.WEATHER.GOV/HASTINGS  (ALL LOWERCASE)