Area Forecast Discussion
Issued by NWS North Platte, NE

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465
FXUS63 KLBF 052349 AAA
AFDLBF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
649 PM CDT THU MAY 5 2016

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 338 PM CDT THU MAY 5 2016

H5 ANALYSIS THIS AFTERNOON INDICATES THE PRESENCE OF AN AMPLIFIED
RIDGE CENTERED JUST EAST OF THE ROCKIES...WITH BOOKEND TROUGHS TO
THE EAST AND WEST.  THE WESTERN TROUGH...OFF THE COAST OF
CALIFORNIA...WILL BEGIN IMPACTING THE HIGH PLAINS AS EARLY AS FRIDAY
EVENING...WITH THE POTENTIAL FOR STORMS.  AT THE SURFACE...SOUTHERLY
WINDS PREVAIL ACROSS THE SANDHILLS...WITH LOW PRESSURE DEVELOPING ON
THE HIGH PLAINS OF EASTERN COLORADO.  TEMPERATURES AS OF 1 PM CDT
WERE MAINLY IN THE UPPER 70S TO LOWER 80S...WITH THE WARMER READINGS
OVER THE CENTRAL SANDHILLS NORTH TO VALENTINE.

OVER THE NEXT 24 HOURS EYES WILL BE ON THE APPROACH OF THE WESTERN
CONUS TROUGH...WHICH WILL HAVE ADVANCED OVER THE MAINLAND...CENTERED
NEAR 29 PALMS.  WAA OFF THE HIGH PLAINS WILL PUSH H85 TEMPS ABOVE
20C FOR MOST PLACES ACROSS THE CWA.  THE LATEST GUIDANCE SUGGESTS
MID 20S OVER SW NEB BY 00Z SATURDAY.  HIGHS WILL WARM...WITH
WIDESPREAD LOW TO MID 80S FAHRENHEIT.  THE WARMEST READINGS ARE
FORECAST ALONG THE NIOBRARA RIVER VALLEY AND ACROSS SOUTHWEST
NEBRASKA.

OVERNIGHT LOWS TONIGHT WILL BE IMPACTED BY THE PRESENCE OF LL WAA
AND A PERSISTENT SOUTH WIND.  THE LATEST NUMERICAL GUIDANCE SUGGESTS
LOWS RANGING FORM THE UPPER 40S ACROSS THE WEST...TO POSSIBLY AS
WARM AS THE MID 50S OVER THE FAR NORTHEAST.  MOST LOCATIONS SHOULD
ONLY LOWER INTO THE LOW 50S.

WILL NEED TO MONITOR THE PROGRESSION OF THE TROUGH AND A NORTHERN
PLAINS COLD FRONT FRIDAY AFTERNOON FOR THE POSSIBILITY OF
CONVECTION.  THE LATEST GUIDANCE HAS THE FRONT ENTERING NORTHWEST
NEBRASKA AROUND 00Z SATURDAY WHILE THE APPROACHING TROUGH COOLS
TEMPERATURES ALOFT. THE LATEST SOUNDINGS FROM THE SANDHILLS REVEALS
INCREASING INSTABILITY IN THE AFTERNOON...WITH LITTLE IN THE WAY OF
CONVECTIVE INHIBITION.  THE CURRENT  THINKING IS THAT STORMS WILL
HOLD OFF UNTIL AFTER 00Z...WITH THE INITIATION TARGETING THE HIGH
PLAINS FIRST...BUT IF A STORM FIRES OVER THE PANHANDLE...SOUTHWEST
OR NORTHWEST NEBRASKA...LARGE HAIL WILL BE POSSIBLE.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 338 PM CDT THU MAY 5 2016

FRIDAY NIGHT THROUGH SUNDAY...THE NAM AND GFS ARE SINKING A COLD
FRONT THROUGH SWRN NEB SATURDAY. AT THE SAME TIME HOT DRY AIR WILL
SURGE THROUGH COLORADO SETTING UP A TRIPLE PT OVER NERN COLORADO OR
NWRN KANSAS. STORMS SHOULD FIRE ON THE TRIPLE PT AND LIFT EAST AND
NORTHEAST THROUGH SWRN NEB. A VERY STRONG CAP WILL BE IN PLACE WITH
H775MB TEMPS AROUND 15C. THE CAP SHOULD WEAKEN ACCORDING TO THE
MODELS. THE POSITION OF THE FRONT SUGGEST THE POTENTIAL FOR
TORNADOES BUT IT APPEARS THIS WOULD BE MORE FAVORED IN THE WARM
SECTOR  ACROSS COLO AND KANSAS. NONETHELESS...THERE IS NO GUARANTEE
OF THE FRONTAL LOCATION SO AREAS OF FAR SWRN NEB ARE OF CONCERN.
OTHERWISE LARGE HAIL AND WIND DAMAGE WOULD BE THE PRIMARY CONCERN.

A 700MB WARM FRONT EMANATING FROM AN UPPER LOW OVER THE SWRN U.S.
SHOULD LIFT THE CONVECTION THROUGH THE FCST AREA SATURDAY NIGHT. BY
SUNDAY...AN H700MB LOW SHOULD BE SOMEWHERE NEAR OR OVER THE SRN NEB
PANHANDLE. RAIN IS EXPECTED ACROSS SHERIDAN COUNTY AND NORTHWEST NEB
WITH HIGHS IN THE 50S...60S ELSEWHERE.

OTHER TSTMS SHOULD DEVELOP ACROSS NERN WY FRIDAY AFTN/EVENING AND
THE MODELS CARRY THIS ACTIVITY SOUTH AND EAST ACROSS NRN NEB FRIDAY
NIGHT. THESE THUNDERSTORMS SHOULD DEVELOP NORTH OF THE COLD FRONT AS
THE MODELS SHOW MOISTURE POOLING BEHIND THE FRONT. THIS SHOULD HELP
PROPEL THE COLD FRONT THROUGH THE FCST AREA. THE LATEST GUIDANCE
INCLUDING BIAS CORRECTION FORECASTS HIGHS IN THE 60S TO AROUND 70
SATURDAY.

SPAGHETTI PLOTS OF SEVERE WEATHER PARAMETERS CONVERGE ON OR JUST
NORTH OF THE NEBRASKA KANSAS BORDER SATURDAY. THE SAME PLOTS FAVOR
SCNTL NEB SUNDAY. THERE IS A CHANCE THE WARM FRONT WILL LIFT NORTH
INTO NCNTL NEB SUNDAY HOWEVER SFC WINDS ARE EAST AND THE MODEL
CONSENSUS SHOWS THE SFC LOW NEAR GRAND ISLAND.

SUNDAY NIGHT THROUGH THURSDAY...THE MORNING RUNS OF THE GFS
ENSEMBLE...GFS OPERATIONAL AND CANADIAN MODELS SHOW A CLOSED H700MB
LOW OVER SCNTL NEB MONDAY MORNING. THE ECM WAS FARTHER NORTHWEST
ACROSS NORTHWEST NEB. THIS LOW SHOULD MOVE SLOWLY EAST PRODUCING
SCATTERED SHOWERS AND THUNDERSTORMS. THESE MODELS STALL A SECOND
UPPER LEVEL LOW ACROSS THE NRN HIGH PLAINS TUESDAY WHICH THEN MOVES
VERY SLOWLY EAST THROUGH THE DAKOTAS WEDNESDAY AND THURSDAY.

COOL AIR WILL CONTINUE ACROSS THE FCST AREA MONDAY THROUGH THURSDAY
WITH HIGHS IN THE 60S. THE BIAS CORRECTED MODEL DATA WAS A FEW
DEGREE COOLER THAN THE STAT GUIDANCE. H500MB TEMPERATURES REMAIN
AROUND -16C AND H700MB TEMPS AROUND 0C PERHAPS SUPPORTING STEEP AFTN
LAPSE RATES AND A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGHOUT
THIS TIME.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 647 PM CDT THU MAY 5 2016

VISUAL FLIGHT RULES OVER WESTERN NEBRASKA THROUGH FRIDAY AFTERNOON
WITH HIGH CIRUS CLOUDS AND SOUTHERLY WINDS.

&&

.HYDROLOGY...
ISSUED AT 338 PM CDT THU MAY 5 2016

RIVER LEVELS CONTINUE TO RUN HIGH ALONG THE ELKHORN...PLATTE...NORTH
PLATTE...AND SOUTH PLATTE RIVER BASINS DUE TO RECENT HEAVY RAINFALL.
THE HIGH RIVER LEVELS WILL CONTINUE THROUGH THE WEEKEND...WITH THE
POSSIBILITY OF ADDITIONAL CONVECTIVE PRECIPITATION. AT THIS TIME...SIGNIFICANT
INCREASES DUE TO THE EXPECTED PRECIPITATION IS NOT EXPECTED.

&&

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

$$

SHORT TERM...JACOBS
LONG TERM...CDC
AVIATION...POWER
HYDROLOGY...JACOBS



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