Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 200602 AAA
AFDLBF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
102 AM CDT WED AUG 20 2014

.UPDATE...
ISSUED AT 521 PM CDT TUE AUG 19 2014

UPDATED TO INCLUDE A SLIGHT CHANCE FOR THUNDERSTORMS FROM SWRN
NEBR INTO CENTRAL NEBRASKA AS THIS EVENING PROGRESSES. LATEST
REGIONAL RADAR MOSAIC SHOWS SCATTERED THUNDERSTORMS FROM NEAR
SCOTTSBLUFF THROUGH FORT MORGAN AND LAST CHANCE COLORADO. THE
LATEST HRRR AND RAP13 INDICATE THIS TO PUSH NORTHEAST AND INCREASE
IN COVERAGE INTO WRN NEBR THIS EVENING. RECENT ISOLATED
DEVELOPMENT NOW IN SHERIDAN AND CHERRY COUNTY ATTM.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 337 PM CDT TUE AUG 19 2014

SHORTWAVE RIDGING ALOFT CURRENTLY RESIDES OVER THE AREA...WITH VERY
LITTLE IN THE WAY OF CLOUD COVER EXCEPT FOR SOME HIGH CIRRUS CLOUDS.
SHORT TERM HRRR MODEL SUGGESTS THUNDERSTORMS WILL DEVELOP OVER THE
HIGHER TERRAIN TO THE WEST LATE THIS AFTERNOON...AND THEN DRIFT EAST
INTO WESTERN NEBRASKA THIS EVENING. LATEST VISIBLE SATELLITE TRENDS
CONFIRMS THIS THINKING...WITH QUITE A BIT IN THE WAY OF TOWERING
CUMULUS FROM CHEYENNE DOWN THROUGH THE DENVER METRO. SOUTHERLY LOW
LEVEL JET WILL INCREASE TO AROUND 35 KTS THIS EVENING...WHICH MAY
HELP SUPPORT STORMS AS THEY TRACK EAST. NOT EXPECTING COVERAGE TO BE
WIDESPREAD...AND DUE TO THE RIDGING ALOFT...NOT REAL CONFIDENT ON
HOW FAR EAST STORMS WILL MAKE IT. LATER TONIGHT...DECENT MID LEVEL
INSTABILITY DEVELOPS ACROSS NORTH CENTRAL INTO NORTHEAST
NEBRASKA...AND EXPECT AT LEAST SCATTERED COVERAGE OF ELEVATED
THUNDERSTORMS TO DEVELOP WITHIN AREA OF ISENTROPIC ASCENT.

A SURFACE TROUGH WILL EXTEND FROM NORTHEAST TO SOUTHWEST WEDNESDAY
AFTERNOON...AND SHOULD BE THE FOCUS FOR SCATTERED LATE AFTERNOON
THUNDERSTORMS. THE NAM MODEL IS THE FARTHEST EAST WITH THE
TROUGH...WHILE THE NMM...ARW AND GEM REGIONAL HOLD THE TROUGH BACK
FROM ROUGHLY AINSWORTH TO IMPERIAL. DECENT INSTABILITY DEVELOPS BY
AFTERNOON ALONG AND EAST OF THE TROUGH...WITH SURFACE BASED CAPES
APPROACHING 4000 J/KG. A BELT OF STRONGER MID LEVEL WINDS WILL ALSO
BE PRESENT BY AFTERNOON ON THE SOUTHERN FLANK OF A SHORTWAVE
CROSSING THE NORTHERN PLAINS. THE SYNOPTIC SET UP APPEARS SIMILAR TO
THE SUNDAY SEVERE EVENT...AND AGREE WITH THE STORM PREDICTION CENTER
SLIGHT RISK FOR SEVERE STORMS EAST OF HIGHWAY 83.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 337 PM CDT TUE AUG 19 2014

THE WEAK FRONT WILL CROSS CENTRAL NEBRASKA WEDNESDAY NIGHT AND
GENERATE A BAND OF THUNDERSTORMS...ESPECIALLY IN CENTRAL AND NORTH
CENTRAL NEBRASKA. MODEL OUTPUT STATISTICS INDICATE PROBABILITY/
COVERAGE OF 20-30 PERCENT IN THE SANDHILLS AND 30-40 PERCENT IN
CENTRAL AND NORTH CENTRAL NEBRASKA. THAT SEEMS REASONABLE. SURFACE
BASED CAPE IN CENTRAL AND NORTH CENTRAL NEBRASKA IS PRETTY HIGH AT
3500-4000J/KG WITH BULK SHEAR (0-6KM) AROUND 30KT. WITH STORM MOTION
240-260 AT 15-25KT...STORM RELATIVE HELICITY IS EXPECTED TO BE
110-200. SEVERE STORMS ARE POSSIBLE INTO THE EVENING...THOUGH WE
WILL NOT INCLUDE THE MENTION IN THE FORECAST FOR WEDNESDAY NIGHT.

A BOUNDARY LIFTING NORTH INTO SOUTHERN NEBRASKA WILL BRING THE
POSSIBILITY OF THUNDERSTORMS TO SOUTH CENTRAL AND SOUTHWEST NEBRASKA
THURSDAY NIGHT. AS THE BOUNDARY MAKES ITS WAY A LITTLE FARTHER NORTH
FRIDAY...THERE IS A POSSIBILITY OF THUNDERSTORMS IN CENTRAL AND
NORTHERN NEBRASKA.

FINALLY...SATURDAY NIGHT AND SUNDAY...A COOL FRONT COMES ACROSS
NEBRASKA AND THE PATTERN IS NOT AS FAVORABLE FOR STRONG CONVECTION.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 102 AM  CDT WED AUG 20 2014

AN AREA OF LIGHT SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS WILL MOVE
NORTHEAST ACROSS SOUTHWEST INTO EASTERN PORTIONS OF NORTH CENTRAL
NEBRASKA OVERNIGHT. FOR WEDNESDAY...A CHANCE FOR THUNDERSTORMS AT
KLBF AFTER 23Z/21ST AND INCLUDED IN A PROB30 FOR 5SM TSRA BKN070CB.
EXPECT TSRA TO DEVELOP AND REMAIN EAST OF KVTN TERMINAL AND DID NOT
INCLUDE THIS TAF ISSUANCE.

&&

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

$$

UPDATE...ROBERG
SHORT TERM...TAYLOR
LONG TERM...SPRINGER
AVIATION...POWER





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