Hail in Nebraska, May 29, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
300 PM CDT FRI MAY 29 2009

.DISCUSSION...
FORECAST CHALLENGE IS TEMPERATURES IN THE NEAR TERM. AT 18Z FEW
CLOUDS WERE MOVING SOUTHEAST ACROSS THE NORTH CENTRAL WITH
TEMPERATURES RANGING FROM 72 AT ONL TO 84 AT IML. SURFACE HIGH
PRESSURE WAS RIDGING NORTHEAST FROM THE SOUTHWEST TO NORTHEAST
ACROSS BBW INTO WESTERN IA WITH A WEAK SURFACE BOUNDARY EXTENDING
FROM A LOW OVER NW SD SOUTHEAST OF CDR TO LNX AND INTO NW MISSOURI.
AT 18Z LAPS DATA SHOW GREATEST INSTABILITY ACROSS THE FAR
SOUTHWEST WHERE CAPE VALUES AOB 1230 J/KG AND POCKETS OF HIGHER
VALUES OVER THE PANHANDLE WHERE LITTLE CIN REMAINED. ACROSS THE
THE NORTH CENTRAL THE CAP IS STILL STRONG WHILE DEWPOINTS WERE ON
THE RISE INTO THE LOWER 50S. THE RUC SOLUTION SHOWS THE BACKDOOR
COLD FRONT ARRIVING BWTN 00Z TO 03Z INTO THE NORTHWEST THAT WILL
MOVE SOUTHEAST...WHILE THE BOUNDARY ACROSS THE SOUTHWEST LIFTS
NORTHEAST INTO THE EVENING. EITHER BOUNDARY COULD BE A FOCUS FOR
THUNDERSTORM DEVELOPMENT AS DISTURBANCE MOVE SOUTHEAST THROUGH MID
EVENING WITH CONVECTION ISOLATED AS MOISTURE REMAINS LIMITED.
OVERNIGHT THE H85 JET STRENGTHENS FROM THE SOUTHWEST WITH THE
SURFACE LOW DEEPENING WHILE MOVING SOUTHEAST INTO IOWA SATURDAY
MORNING WITH THE FRONT TO THE SOUTH AND BACKED WEST TO THE FRONT
RANGE BY SATURDAY MORNING.

ON SATURDAY THE UPPER RIDGE BUILDS EAST WITH THE SURFACE HIGH
PRESSURE CENTER BUILDING SOUTHEAST THROUGH THE NORTHERN MIDWEST THAT
WILL RETURN UPSLOPE FLOW ON THE HIGH PLAINS. POPS LOWERED EAST OF
THE PANHANDLE AS MAIN FORCING SHIFTS WESTWARD WITH THE CHANCE OF
CONVECTION DEVELOPING ON THE HIGH PLAINS AND MOVING SOUTHEAST INTO
THE EVENING. THE EASTWARD PROGRESSION OF STORMS SHOULD BE LIMITED
BY DRIER AIR AS INDICATED IN NAM PROFILE SOUNDINGS. THEN H85
TEMPERATURES CREATE A POTENTIAL SPREAD IN TEMPERATURES ON SATURDAY
AS READINGS REACH INTO THE MID 20S IN THE SOUTHWEST TO AROUND 13
DEG C OVER THE NORTH CENTRAL. ALTHOUGH MID AND HIGH LEVEL
CLOUDINESS COULD HINDER HEATING POTENTIAL IN THE WEST BY AFTERNOON
WITH FORECAST HIGHS A MODEL BLEND.

SATURDAY NIGHT INTO SUNDAY ANOTHER COLD FRONT WILL MOVE ACROSS
MONTANA INTO NORTHWEST NEBRASKA BY SUNDAY EVENING. MODELS ARE
SHOWING SOME VARIATION IN POTENTIAL QPF GENERATED AS THIS SYSTEM
MOVES SOUTHEAST AND SLOWS FOR RAINFALL INTO THE EXTENDED PERIOD.
TAILORED FORECAST TOWARD A FORECAST AND MODEL BLEND THAT KEEPS
POPS GOING SUNDAY NIGHT INTO MONDAY WHEN THE FRONT WILL BE
POSITIONED EAST THROUGH SOUTHERN NEB. TEMPERATURES WILL TREND
UPWARDS AS MOISTURE DEEPENS FOR LOWS IN THE 50S TO LOW 60S INTO
MONDAY AS THE FRONTAL SYSTEM MOVES SLOWLY SOUTH INTO THE EXTENDED
PERIOD.

EXTENDED FORECAST FROM MONDAY THROUGH FRIDAY MOVES TOWARD A
COOLDOWN BEYOND MONDAY. LONG RANGE MODELS ARE IN FAIR AGREEMENT
WITH A COLD FRONT TO PUSH SOUTH ON MONDAY WITH EVENTUAL FRONTAL
POSITION TO IMPACT TEMPERATURES. THE FRONT PUSHES WELL SOUTH TO
THE GULF COAST STATES THROUGH WEDNESDAY THAT WILL ALLOW COOLER
CANADIAN AIR TO FLOW SOUTH TO DRIVE TEMPERATURES DOWN INTO THE
60S. BY THE END OF THE PERIOD MODELS DO DIVERGE IN HANDLING THE
CANADIAN HIGH PRESSURE WITH GFS A FASTER BUILDING THE HIGH
EASTWARD. TRENDED TEMPERATURES TOWARD THE GFS MEX GUIDANCE NUMBERS
THAT MAY NEED TO BE ADJUSTED DOWN FURTHER IF THE HIGH REMAINS
SETTLED OVER THE PLAINS. THE CHANCE FOR RAINFALL WILL FOCUS MONDAY
NIGHT INTO TUESDAY FOR HIGHEST POPS.

&&

.AVIATION...

BACKDOOR COLD FRONT WORKING S ACROSS CENTRAL NEB...WITH A FOCUS FOR
THUNDERSTORM DEVELOPMENT THIS EVENING. THUNDERSTORMS MAY BRIEFLY
IMPACT THE TAF SITES...HOWEVER MODELS HAVE SHIFTED THE FOCUS A
LITTLE EAST. KLBF SEEMS LESS LIKELY THAN KVTN SO HAVE REMOVED ALL
MENTION OF T FROM KLBF TAF. DID HOLD TO A CB ON THE CLOUDS FOR
KVTN...BUT CHANCES SEEM TO LOW TO CONTINUE TO INCLUDE T AT THIS
TIME...MAINLY DUE TO LACK OF MOISTURE. OVERNIGHT VARIABLE LIGHT
WINDS SHIFT TO THE NORTH BEHIND THE FRONT. IN SHORT VFR CONDITIONS
EXPECT ACROSS THE REGION...ONLY EXCEPTION WILL BE BRIEF MVFR VSBY
IN ISOLATED TSRA.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&

SHORT TERM/EXTENDED...KECK
AVIATION...MASEK

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
309 PM CDT FRI MAY 29 2009

NEZ004>010-022>029-035>038-056>059-069>071-094-302015-
SHERIDAN-EASTERN CHERRY-KEYA PAHA-BOYD-BROWN-ROCK-HOLT-GARDEN-
GRANT-HOOKER-THOMAS-BLAINE-LOUP-GARFIELD-WHEELER-ARTHUR-MCPHERSON-
LOGAN-CUSTER-DEUEL-KEITH-PERKINS-LINCOLN-CHASE-HAYES-FRONTIER-
WESTERN CHERRY-
309 PM CDT FRI MAY 29 2009 /209 PM MDT FRI MAY 29 2009/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WESTERN AND
NORTH CENTRAL NEBRASKA.

.DAY ONE...TONIGHT.

A WEAK FRONTAL BOUNDARY WILL MOVE ACROSS CENTRAL NEBRASKA THIS
EVENING. WHILE MOISTURE IS LIMITED...WIND PROFILES AND
INSTABILITY ARE FAVORABLE FOR THUNDERSTORM DEVELOPMENT. A FEW
THUNDERSTORMS HAVE THE POTENTIAL TO BECOME SEVERE...WITH LARGE
HAIL TO BE THE PRIMARY THREAT. HOWEVER...AN ISOLATED TORNADO CAN
NOT BE RULED OUT. THE AREA OF GREATEST RISK WILL BE ALONG A LINE
FROM THEDFORD TO BROKEN BOW.

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

A SLIGHT CHANCE FOR THUNDERSTORMS IS EXPECTED SATURDAY AFTERNOON
AND EVENING FOR FAR WESTERN NEBRASKA.

A BETTER CHANCE FOR THUNDERSTORMS WILL EXIST SUNDAY AFTERNOON
THOUGH MONDAY NIGHT AS A COLD FRONT STALLS SOUTH OF THE OUTLOOK
AREA...ALLOWING MOISTURE AND INSTABILITY TO POOL. THUNDERSTORMS
MAY BE SLOW MOVING WITH HEAVY RAINFALL THE PRIMARY THREAT.

CONTINUED THUNDERSTORM CHANCES WILL REMAIN A POSSIBILITY WITH AN
ACTIVE PERIOD THROUGH MOST OF NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TO MONITOR SUPERCELL
THUNDERSTORMS THIS ALONG A LINE FROM THEDFORD TO BROKEN BOW.

&&

THIS PRODUCT IS NOW AVAILABLE...ALONG WITH OTHER WEATHER...
HYDROLOGICAL AND CLIMATOLOGICAL INFORMATION...AT
HTTP://WWW.WEATHER.GOV/NORTHPLATTE

MASEK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORTH PLATTE NE
613 PM CDT FRI MAY 29 2009

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0612 PM     HAIL             1 S WOOD LAKE           42.62N 100.24W
05/29/2009  M0.50 INCH       CHERRY             NE   PUBLIC

&&

SJACOBS