Hail in Nebraska, September 17, 2010

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1122 PM CDT FRI SEP 17 2010

.UPDATE...
THUNDERSTORMS DEVELOPING INTO THE NORTH CENTRAL GENERALLY SOUTH OF
HIGHWAY 91. SPC HAS ISSUED SEVERE THUNDERSTORM WATCH UNTIL 6 AM
CDT FOR CUSTER...BLAINE...LOUP...GARFIEDL AND WHEELER COUNTIES.
FORECAST GRIDS AND TEXT PRODUCTS UPDATED.

&&

.PREV DISCUSSION... /ISSUED 314 PM CDT FRI SEP 17 2010/

..A SHARP COOLDOWN SATURDAY WITH LIGHT RAIN/DRIZZLE POSSIBLE...THEN
GENERALLY MILD NEXT WEEK...

SYNOPSIS...
AS OF 20Z...SFC COLD FRONT LOCATED FROM NEAR TEKAMAH THROUGH GRAND
ISLAND AND GOODLAND KANSAS. SECONDARY COLD FRONT WITH THE REAL PUSH
OF COLD AIR LOCATED ACROSS NORTHERN WYOMING THROUGH NWRN SOUTH
DAKOTA. BENEATH SFC HIGH...LIGHT SNOW FALLING AT GLASGOW AND GREAT
FALLS AND OTHER NEARBY LOCATIONS. TEMPS IN THE 30S ACROSS CNTRL AND
ERN MT.

DISCUSSION...

DIFFERENCES EXIST BTWN THE NAM/GFS WRT PLACEMENT OF LIFT AND
RESULTING QPFS. WHILE EACH MODEL IS CONSISTENT IN ITS OWN
RESPECT...THE GFS CERTAINLY IS THE WETTEST MODEL ACROSS WRN AND
NCTRL NEBR OVERNIGHT...SYNOPTICALLY...THE GFS SOLUTION MAKES SENSE.
POSITION OF H85 FRONT TONIGHT WITH SOME WEAK INSTABILITY ALOFT
SHOULD YIELD SCT SHOWERS AND ISOLATED TSTMS OVERNIGHT. DUE TO MODEL
DIFFERENCES...HAVE KEPT POPS FROM 30 TO 40 PERCENT MAINLY EAST OF
HWY 83 AND SLIGHT CHC TO THE WEST.

HIGH TEMPS SATURDAY TO BE SHARPLY COOLER. THE PRESENCE OF STRATUS
AND LIGHT RAIN/DRIZZLE TO KEEP HIGHS DOWN IN THE UPPER 40S FAR
NORTHWEST TO THE LOWER/MID 50S REMAINDER. ADDITIONALLY...AREAS OF
FOG EXPECTED IN THE MORNING. SOME MODEL UNCERTAINTY REMAINS FOR
SUNDAY AS THE ECMWF SHOWS WARM FRONT QUICKLY LIFTS NORTH WITH HIGHS
IN THE 80S POSSIBLE SWRN HALF. I FEEL THIS SOLUTION CAN BE
DISCOUNTED. HAVE LEANED TOWARDS A 50/50 BLEND OF THE THE 09Z
SREF/12Z MET GUIDANCE. THIS FCSTS MID 60S NERN HALF TO THE UPPER 70S
SWRN QUARTER OF FORECAST AREA. MUCH WILL DEPEND ON WESTERN EDGE OF
CLEARING LINE. STRATUS MAY PERSIST ACROSS MUCH OF AREA TO LIMIT
HIGHS.

A NICE WARMUP MONDAY IN THE 80S...AS UPPER RIDGE BEGINS TO BREAK
DOWN AND SFC FRONT APPROACHES NW LATE IN THE DAY. STILL A SLIGHT CHC
FOR AFTN TSTMS. SOME FIRE WEATHER CONCERN WEST AS LOWEST RH MAY FALL
TO 20-25 PERCENT. CHC FOR SHOWERS MONDAY NIGHT AND TUESDAY
ASSOCIATED WITH PASSAGE OF UPPER TROUGH AND UPPER DISTURBANCE. POST
FRONTAL HIGHS TUESDAY AND WEDNESDAY COOLER IN THE 70S. NEXT CHC FOR
SHOWERS COMES WEDNESDAY/THURSDAY WITH ANOTHER COLD FRONT.

AVIATION...

LOW CONFIDENCE FORECAST TODAY AS SHORT TERM MODELS IN DISAGREEMENT
WITH A POTENTIALLY ACTIVE NIGHT. FIRST OFF...COLD FRONT HAS PUSHED
INTO S CENTRAL NEB AND WILL BE THE FOCUS FOR EVENING TSRA. SHOULD
REMAIN SE OF THE KLBF TERMINAL...BUT WILL NEED WATCH. NEXT CONCERN
WILL BE THE NOCTURNAL LOW LEVEL JET...NOSING INTO SW NEB.  TIMING IN
KLBF TAF MAY NEED TO BE BUMPED EARLIER. FINALLY STRATUS EXPECTED TO
BECOME WIDESPREAD OVERNIGHT WITH COOLER AIR AND UPSLOPE EASTERLY
WINDS. HIGHER CONFIDENCE IN DEVELOPMENT OF STRATUS...ALTHOUGH LOWER
CONFIDENCE IN HEIGHT...WHICH MAY BE AS LOW AS TO DROP CIGS LESS THAN
500FT. SOME DRIZZLE MAY ACCOMPANY THE STRATUS FOR TOMORROW AS AN
UPPER LEVEL DISTURBANCE MOVES ACROSS THE AREA.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...SEVERE THUNDERSTORM WATCH UNTIL 6 AM CDT SATURDAY FOR NEZ026>029-
038.

&&

SHORT TERM/EXTENDED...ROBERG
AVIATION...KECK

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1046 PM CDT FRI SEP 17 2010

NEZ004>010-022>029-035>038-056>059-069>071-094-190400-
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-
1046 PM CDT FRI SEP 17 2010 /946 PM MDT FRI SEP 17 2010/

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

.DAY ONE...TONIGHT.

GENERAL THUNDERSTORM DEVELOPMENT IS POSSIBLE EAST AND SOUTH OF AN
ONEILL TO NORTH PLATTE LINE. A FRONTAL BOUNDARY WILL STALL SOUTH
OF THE FORECAST AREA OVERNIGHT. ENOUGH ELEVATED INSTABILITY WILL
REMAIN BEHIND THIS FRONT FOR A FEW STORMS...SOME MAY PRODUCE SMALL
HAIL AND STRONG GUSTY WINDS.

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

THUNDERSTORMS WILL BE POSSIBLE ON MONDAY AFTERNOON AND EVENING AS
A COLD FRONT MOVES THROUGH THE REGION. INSTABILITY IS EXPECTED TO
INCREASE THROUGH THE DAY ON MONDAY. WIND SHEAR WILL BE SUFFICIENT FOR
THE POSSIBILITY OF A FEW STORMS BECOMING SEVERE. LARGE HAIL AND
STRONG WIND GUSTS ARE THE THE PRIMARY THREATS.

THE FRONT RETREATS BACK NORTH ON WEDNESDAY AHEAD OF THE NEXT
SYSTEM POISED TO ARRIVE ON THURSDAY...AT THIS TIME...GENERAL
STORM DEVELOPMENT WOULD BE POSSIBLE ON BOTH DAYS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT.

&&

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

POWER