Damaging Winds in Nebraska, June 21, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
324 PM CDT SUN JUN 21 2009

.SYNOPSIS...
A SURFACE TROUGH OF LOW PRESSURE HAS LIFTED EAST INTO CENTRAL AND
EASTERN NEBRASKA TODAY. BEHIND THIS FEATURE...CLEAR SKIES LIGHT
WESTERLIES AND DRIER AIR HAS FILTERED INTO THE AREA. H5 ANALYSIS
THIS MORNING HAS HIGH PRESSURE OVER SERN ARKANSAS...AND A TROUGH
OVER THE WEST COAST. A COUPLE OF DISTURBANCES WERE NOTED...THE FIRST
OVER LAKE TAHOE AND THE SECOND...LIFTING NORTH ACROSS THE BIG HORN
MTS.

&&

.DISCUSSION...

.NEAR TERM...TONIGHT THROUGH WEDNESDAY NIGHT...MAIN FORECASTING
CHALLENGE IN THE NEAR TERM DEALS WITH TEMPERATURES AND LOW
PRECIPITATION CHANCES. FOR TONIGHT...RETAINED LOW PRECIPITATION
CHANCES OVERNIGHT FOR LOCATIONS NORTH OF INTERSTATE 80 FOR ISOLATED
TSRAS. BOTH THE NAM AND GFS SOLNS THIS MORNING SHOW DECENT MID LEVEL
WAA DEVELOPING ACROSS NERN COLORADO...LIFTING NORTHEAST INTO THE CWA
OVERNIGHT. FORECAST TIME SECTIONS TONIGHT ARE INDICATIVE OF TOP DOWN
SATURATION...SO HAVE CHOSEN TO KEEP POPS AND QPFS LOW TONIGHT.

SHIFTING TO TOMORROW...A DIFFUSE...WEAK FRONTAL BOUNDARY WILL LIFT
NORTH ACROSS NORTHEASTERN NEBRASKA TOMORROW MORNING...BECOMING
ANCHORED OVER SERN SD AND NERN NEBRASKA MONDAY AFTERNOON. CAPES
ACROSS NERN NEBRASKA MONDAY AFTERNOON WILL PEAK ABOVE 3000 J/KG EAST
OF HIGHWAY 183 WITH CORRESPONDING LIS OF -6 TO -8 BY 21Z TOMORROW
AFTERNOON. CAP STRENGTH IS KEY HERE AND CONVECTION WILL BE
EXCLUSIVELY DEPENDANT ON BREAKING THIS. GUT FEELING IS THAT THE CAP
WILL HOLD...HOWEVER...IF IT DOES NOT...50KTS OF BULK SHEAR WILL BE
SUFFICIENT FOR A SUPERCELL. FEEL THE 3000+ CAPES CANNOT BE
IGNORED...SO INSERTED SOME ISOLATED CHANCES IN THE NORTHEAST.

BETTER CHANCES FOR PRECIPITATION ARRIVE ON TUESDAY AFTERNOON AND
EVENING AS A FRONTAL BOUNDARY APPROACHES THEN STALLS ACROSS NORTHERN
NEBRASKA. WEAK MID LEVEL DYNAMICS WILL LIFT ACROSS THE DAKOTAS AND
HIGH PLAINS LATE TUESDAY AS A TROUGH OF LOW PRESSURE TRAVERSES THE
NORTHERN TIER OF STATES.

AS FOR TEMPERATURES...THE MAV AND MET GUIDANCE HAVE DONE A FLIP FROM
YESTERDAY WITH THE MET COOLER THAN THE MAV NUMBERS. BOTH ARE
INDICATING LIGHT SERLY WINDS BOTH DAYS...SO DECIDED TO UTILIZE THE
SLIGHTLY COOLER MET NUMBERS.

.LONG TERM...THURSDAY THROUGH THROUGH SUNDAY...
AGREEMENT BETWEEN THE EURO AND GFS SOLNS THIS MORNING BEGINNING TO
WAVER SOMEWHAT. MAIN DIFFERENCES NOTED BETWEEN THE TWO MODELS THIS
MORNING LIE WITH THEIR H5 PATTERN DISCREPANCIES LATER IN THE WEEK.
THE EURO SOLUTION IS MUCH SLOWER IN EJECTING A CLOSED LOW FROM THE
SWRN US COAST...WHICH WOULD FAVOR THE UPPER LEVEL HIGH PERSISTING
INTO SATURDAY. THE GFS LIFTS THIS OUT MUCH FASTER...BRINGING COOLER
TEMPS AND PRECIPITATION CHANCES TO THE AREA BEGINNING THURSDAY
NIGHT. GENERALLY FOLLOWED THE NATIONAL GUIDANCE ON THIS ONE AND
FOLLOWED THE SLOWER EURO SOLUTION. ON THIS NOTION...HAVE FAVORED
WARMER TEMPS AND MAINLY DRY CONDS. THE EXCEPTION WILL BE OVER THE
NRN FCST AREA...WHICH WILL LIE IN THE SOUTHERN PORTION OF THE RING
OF FIRE. HAVE OPTED FOR LOW POPS IN THESE AREAS AS PRECIP TIMING
AND LOCATION WILL BE HIGHLY DEPENDENT ON THE TRACK OF EMBEDDED
DISTURBANCES. BY LATE SATURDAY...THE RIDGE WILL FLATTEN
SIGNIFICANTLY AS THE BEFORE MENTIONED LOW LIFTS ACROSS THE
INTERMOUNTAIN WEST...FLATTENING THE RIDGE ACROSS THE CENTRAL PLAINS.
GENERALLY WENT WITH 90S FOR HIGHS...WITH SOME COOLER READINGS FOR
SATURDAY AND SUNDAY.

&&

.AVIATION...
CEILINGS ARE CONTINUING TO LIFT ACROSS NORTH CENTRAL NEBRASKA AT
18Z WITH VISUAL FLIGHT RULES THIS AFTERNOON AND TONIGHT FOR
TERMINALS KLBF AND KVTN. MODELS AGREE WITH THAT ISOLATED HIGH BASED
THUNDERSTORMS MAY DEVELOP INTO THE NEB PANHANDLE THIS EVENING THEN
LIFT NORTHEAST OVERNIGHT. CEILINGS WILL BE AOB 10KFT WHERE LITTLE
PRECIPITATION MAY REACH THE GROUND ALTHOUGH WIND GUSTS MAY BE A
CONCERN. FOR NOW THUNDERSTORMS IN THE VICINITY MENTIONED IN
TERMINALS BEYOND 04Z WITH AREAL COVERAGE TO BE ISOLATED AS
DISTURBANCE LIFTS NORTHEAST THROUGH MONDAY MORNING THAT WILL BE
REEVALUATED FOR LATER TAF ISSUANCES.
&&

.LBF WATCHES/WARNINGS/ADVISORIES...NONE

.AVIATION...KECK
.SHORT AND LONG TERM...BUTTLER

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
256 PM CDT SUN JUN 21 2009

NEZ004>010-022>029-035>038-056>059-069>071-094-221000-
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-
256 PM CDT SUN JUN 21 2009 /156 PM MDT SUN JUN 21 2009/

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

.DAY ONE...TONIGHT.

GENERAL THUNDERSTORM DEVELOPMENT IS POSSIBLE IN THE EASTERN
PANHANDLE...THEN OVERNIGHT...MAINLY ACROSS THE CENTRAL SANDHILLS
AS A WEAK DISTURBANCE TRAVERSES THE OUTLOOK AREA.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

BACKDOOR COLD FRONT WILL SERVE AS THE FOCUS FOR THUNDERSTORM
DEVELOP LATE TUESDAY AND AGAIN WEDNESDAY NIGHT...WITH A SLIGHT
RISK FOR SEVERE THUNDERSTORMS...MAINLY NEAR AND NORTH OF HIGHWAYS
2 AND 91. THUNDERSTORM DEVELOPMENT...MAINLY ISOLATED...REMAINS
POSSIBLE THEREAFTER AS AN UPPER LEVEL RIDGE BUILDS WESTWARD AND REMAINS
ANCHORED ACROSS THE CENTRAL UNITED STATES.

.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

KECK