Damaging Wind in Nebraska, July 19, 2011

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
930 PM CDT TUE JUL 19 2011

.UPDATE...
UPDATED FORECAST AND CANCELLED HEAT ADVISORY FOR THE WESTERN ZONES.
PRECIPITATION OVER NORTHEAST COLORADO AND THE WESTERN NEBRASKA
PANHANDLE LOOKS TO HAVE A LEGITIMATE SHOT TO ENTER THE EASTERN
NEBRASKA PANHANDLE AND PORTIONS OF WESTERN NEBRASKA THROUGH
MIDNIGHT. UPDATED WIND FORECAST REMAINDER OF FORECAST LOOKS TO BE
ON TRACK.

&&

.PREV DISCUSSION... /ISSUED 304 PM CDT TUE JUL 19 2011/

DISCUSSION...
THE MASSIVE UPPER LEVEL RIDGE CENTERED OVER THE LOWER MISSOURI
BASIN THIS AFTERNOON IS FCST TO MIGRATE EAST AND FLATTEN ACROSS THE
OHIO VALLEY BY FRIDAY. THE RIDGE WILL RETROGRADE WEST INTO KS/OK
THIS WEEKEND AND THEN BUILD NORTH INTO THE CENTRAL PLAINS NEXT
WEEK PRODUCING ANOTHER ROUND OF HEAT AND HUMIDITY BEGINNING FRIDAY
AND CONTINUING INTO NEXT WEEK.

A COLD FRONT WILL DROP THROUGH NWRN NEB TONIGHT AND THEN THROUGH
THE FCST AREA WEDNESDAY BECOMING STATIONARY ACROSS KS ON THURSDAY.
THE FRONT WILL PRODUCE A BREAK IN THE HEAT WITH HIGHS IN THE UPPER
80S TO LOWER 90S WEDNESDAY AND THURSDAY. THE FRONT WILL LIFT NORTH
INTO SOUTH DAKOTA FRIDAY WITH HIGHS RISING BACK INTO THE MID AND
UPPER 90S ACROSS PARTS OF NEBRASKA.

THE HEAT ADVISORY FOR PARTS OF WRN NEB CAN BE CANCELLED AT 9 PM
MDT THIS EVENING. NO ADVISORY IS EXPECTED WEDNESDAY IN THE WEST AS
TEMPS AND HUMIDITY WILL BE RELATIVELY LOW. THE HEAT WARNING CAN
CONTINUE ACROSS THE REST OF THE FORECAST AREA BUT INDICATIONS ARE
THE FRONT WILL MAKE SUFFICIENT PROGRESS WEDNESDAY MORNING TO ALLOW
EARLY CANCELLATION WEDNESDAY ACROSS A FEW AREAS OF NCNTL NEB.
ELSEWHERE HEAT INDEXES SHOULD REACH 100 TO 105.

THE GFS SUGGESTS HEAT ADVISORIES AND HEAT WARNINGS MAY BE REQUIRED
EAST OF HIGHWAY 83 ON FRIDAY AS THE FRONT LIFTS NORTH AND LATER
FCSTS MAY INCLUDE HIGHLIGHTS. OTHERWISE ISOLATED POPS WERE
SUGGESTED BY A BLEND OF NAM AND GFS THROUGH THURSDAY NIGHT. THE
NAM AND DGEX SUGGESTED ISOLATED STORMS COULD DEVELOP FRIDAY
AFTERNOON AND OVERNIGHT AS A WEAK DISTURBANCE LIFTS THROUGH WRN
NEBRASKA. NO OTHER RAINFALL IS EXPECTED THROUGH DAY 7. HPC
SUGGESTED 1/4 INCH OR LESS RAINFALL THROUGH DAY 5 WHILE 1/3 OF AN
INCH OR LESS WAS SUGGESTED BY THE GFS/ECMWF/GEM/ENSEMBLE SUPER ENSEMBLE.

SPC SUGGESTED 5 PERCENT PROBABILITY OR ISOLATED SEVERE STORM POTENTIAL
THIS EVENING ACROSS THE PANHANDLE...EAST AND SOUTHERN ZONES LATE
WEDNESDAY NEAR THE FRONT AND FROM KIML TO KVTN AND EAST THURSDAY
EVENING AS THE FRONT BEGINS TO LIFT BACK NORTH. WIND DAMAGE WOULD
APPEAR TO BE THE OPERATIVE THREAT THIS EVENING AND WEDNESDAY AS
THERE APPEARS TO MOISTURE ALOFT BUT WIDE DELTA T/TD SPREADS NEAR
THE SFC. THE 0-6KM BULK SHEAR NEAR 40KT THURSDAY MIGHT BE
SUFFICIENT FOR LARGE HAIL.

AVIATION...

A DRY AND QUIET NEXT 24 HOURS IS EXPECTED AT BOTH KLBF AND KVTN.
FORECAST SOUNDINGS WOULD INDICATE A SLIGHT INCREASE IN MOISTURE IN
THE MID AND HIGHER LEVELS SO MAY SEE SOME SCATTERED CLOUDS THROUGH
THIS EVENING AND TONIGHT...BUT NONE THAT WILL CAUSE CEILING
RESTRICTIONS. A WEAK /AND DRY/ FRONTAL BOUNDARY IS PROJECTED TO MOVE
ACROSS NEBRASKA ON WEDNESDAY. CURRENT INDICATIONS ARE THAT THE
BOUNDARY WILL PASS LATE IN THE MORNING WITH WINDS SWITCHING OVER TO
THE NORTHWEST. HAVE TRENDED THE FORECAST TOWARDS THE WIND SHIFT BUT
THIS COULD BE DELAYED IF THE FRONT MOVES THROUGH SLOWER.

HYDROLOGY...

AFTER HEAVY RAINS FELL THIS PAST WEEK OVER COLORADO...THE SOUTH
PLATTE RIVER HAS RISEN AND WILL CONTINUE TO RISE OVER THE NEXT
SEVERAL DAYS. THE SOUTH PLATTE IS FORECAST TO CREST LATER THIS WEEK
AT BOTH ROSCO AND NORTH PLATTE. AT ROSCO THE CREST IS ANTICIPATED TO
BE JUST UNDER FLOOD STAGE...WHILE AT NORTH PLATTE THE RIVER SHOULD
CREST AROUND 10.0 FEET WHICH IS 3.0 FEET BELOW FLOOD STAGE. ALTHOUGH
THE NORTH PLATTE RIVER HAS BEEN RECEDING /LEWELLEN IS SET TO FALL
BELOW FLOOD STAGE THIS EVENING/...HIGH FLOWS CONTINUE ESPECIALLY
DOWNSTREAM OF LAKE MCCONAUGHY. THE HIGH RIVER LEVELS FROM BOTH THE
NORTH AND SOUTH PLATTE RIVERS HAVE CAUSED THE THE MAIN STEM OF THE
PLATTE RIVER TO RISE ABOVE FLOOD STAGE FROM MAXWELL THROUGH BRADY.
THE STAGE AT BRADY IS FORECAST TO SLOWLY RISE THROUGH THIS WEEK.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...EXCESSIVE HEAT WARNING UNTIL
7 PM CDT /6 PM MDT/ WEDNESDAY FOR NEZ005>010-025>029-037-038-059-069>071.

&&

SHORT TERM/EXTENDED...POWER
AVIATION...POWER

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1118 PM CDT TUE JUL 19 2011

NEZ004>010-022>029-035>038-056>059-069>071-094-210430-
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-
1118 PM CDT TUE JUL 19 2011 /1018 PM MDT TUE JUL 19 2011/

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

.DAY ONE...TONIGHT.
THUNDERSTORMS WILL MOVE ACROSS WESTERN NEBRASKA THROUGH THE EARLY
MORNING HOURS...GENERALLY WEST OF HIGHWAY 61 FROM OGALLALA TO
HYANNIS TO MERRIMAN. STORMS ARE EXPECTED TO REMAIN BELOW SEVERE
LIMITS. DAMAGING THUNDERSTORM WINDS WOULD BE THE MAIN THREAT.

WARM AND HUMID CONDITIONS WILL REMAIN ACROSS PORTIONS OF SOUTHWEST
INTO NORTH CENTRAL NEBRASKA AS TEMPERATURES WILL ONLY FALL INTO
THE MID 70S IN SOME LOCATIONS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

SLIGHTLY LOWER HUMIDITY WEDNESDAY WILL RESULT IN HEAT INDICES OF
100 TO 105 IN NORTH CENTRAL TO SOUTHWEST NEBRASKA.

HOT AND HUMID CONDITIONS LOOK TO RETURN FOR FRIDAY AND SATURDAY
WITH HEAT INDEX VALUES OF 100 DEGREES OR ABOVE GENERALLY FOR
LOCATIONS EAST OF HIGHWAY 83.

THERE ARE ALSO PERIODIC CHANCES FOR THUNDERSTORMS OVER THE NEXT
WEEK. WIDESPREAD SEVERE STORMS IN THE NEXT SEVERAL DAYS ARE NOT
ANTICIPATED AT THIS TIME...HOWEVER AN ISOLATED STRONG TO SEVERE
STORM CANNOT BE DISCOUNTED.

.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

MP