000
FXUS63 KLBF 141744
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1244 PM CDT FRI JUN 14 2013

.SYNOPSIS...
ISSUED AT 355 AM CDT FRI JUN 14 2013

AT 08Z...ANALYSIS OF THE MSL DATA SHOWED LOW PRESSURE CENTERED OVER
EASTERN COLORADO NORTH OF EADS AND OVER NORTH CENTRAL COLORADO NEAR
FT. COLLINS. A FRONT WAS DRAPED BETWEEN THE LOWS IN COLORADO AND
ACROSS CENTRAL KANSAS TO NEAR TOPEKA. SURFACE DEWPOINTS ACROSS
CENTRAL KANSAS WERE 65-70 SOUTH OF THE FRONT AND 55-65 NORTH OF THE
FRONT. WIND AND DEWPOINT FIELDS SHOWED DECENT SURFACE MOISTURE
CONVERGENCE FROM NORTHEAST TO NORTH CENTRAL KANSAS. IN UPPER
LEVELS...WATER VAPOR IMAGERY INDICATED A MATURING CYCLONE OVER
CENTRAL IDAHO.

&&

.UPDATE...
ISSUED AT 1243 PM CDT FRI JUN 14 2013

LATE THIS MORNING THE COLD FRONT EXTENDS FROM NEAR MERRIMAN TO BIG
SPRINGS. PRESSURE RISES BEHIND THE FRONT ARE NOT AS STRONG AS THEY
WERE EARLIER THIS MORNING...AND THE FRONT APPEARS TO BE SLOWING
SOMEWHAT. SHORT TERM MODELS STILL PUSH THE FRONT INTO THE FAR
EASTERN AND SOUTHEASTERN PORTIONS OF THE FORECAST AREA LATE THIS
AFTERNOON...FROM NEAR ONEILL TO CURTIS. ALONG AND EAST OF THIS
LINE WILL SEE THE POSSIBILITY OF SFC BASED TSTM DEVELOPMENT ALONG
THE FRONT. LARGE TEMPERATURE DEW POINT SPREADS WILL KEEP STORM
BASES HIGH...WITH LARGE HAIL AND DAMAGING OUTFLOW WINDS THE MAIN
SEVERE THREATS.

FOR TONIGHT...THE 700 MB WARM FRONT WILL REMAIN EAST TO WEST
ACROSS WESTERN AND CENTRAL NEBRASKA...WHILE THE 850 MB WARM FRONT
LIFTS BACK NORTH INTO THE AREA FROM THE SOUTH. APPEARS FAVORABLE
FOR ELEVATED THUNDERSTORM DEVELOPMENT AS A 40 KT LLJ FEEDS NORTH
ACROSS WESTERN KS. ELEVATED INSTABILITY IS PROJECTED TO BE AROUND
1000 J/KG ALONG I-80...WITH VERY STEEP MID LEVEL LAPSE RATES.
SHEAR IS QUITE FAVORABLE...AND WOULD NOT BE SURPRISED TO SEE A FEW
ELEVATED SUPERCELLS WITH LARGE HAIL POTENTIAL.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CDT FRI JUN 14 2013

AS THE FRONT LIFTS NORTHWARD...MOISTURE CONVERGENCE ALONG THE FRONT
WILL CONTINUE TO DESTABILIZE THE CONDITIONS THROUGH THIS AFTERNOON
ALONG THE FRONT ACROSS SOUTHERN AND EASTERN NEBRASKA AND NORTHERN
KANSAS. SCATTERED THUNDERSTORMS WILL DEVELOP LATE THIS AFTERNOON OR
EARLY EVENING ACROSS CENTRAL THROUGH SOUTHWEST NEBRASKA. SURFACE
BASED CONVECTIVE POTENTIAL INCREASES TO MORE THAN 4000J/KG IN
CENTRAL AND SOUTH CENTRAL NEBRASKA WITH 3000J/KG OR HIGHER AS FAR
WEST AS AINSWORTH...BROKEN BOW AND NORTH PLATTE. WE HAVE EXTENDED
THUNDERSTORMS INTO THOSE AREAS. AT 35-40KT...THERE MAY BE ENOUGH
BULK SHEAR IN THE 0-6KM LAYER TO ALLOW HAIL TO DEVELOP AND VORTICITY
ALONG THE FRONT COULD SUPPORT ROTATING UPDRAFTS. FOR NOW...WE WILL
NOT PUT SEVERE WORDING IN THE THUNDERSTORMS FOR THIS AFTERNOON
YET.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 355 AM CDT FRI JUN 14 2013

INITIALLY IN THE EXTENDED PERIODS THE UPPER LEVELS WILL BE
CHARACTERIZED WITH TROUGHS OFF EACH RESPECTIVE COAST OF THE
CONTIGUOUS 48...EFFECTIVELY BOOKENDING A BROAD RIDGE OVER THE
CENTRAL US.  A TRIO OF CLOSED LOWS NOTED BY THE GLOBAL MODELS AND
ENSEMBLES WILL BE LOCATED MAINLY NORTH OF THE US/CANADIAN
BORDER...WITH THE FIRST OFF THE COAST OF BC...THE NEXT CENTERED OVER
SASKATCHEWAN...AND THE THIRD ANCHORED ATOP NORTHERN QUEBEC.  WITH
SOLID LONG RANGE MODEL AGREEMENT...THE CLOSED LOW OVER THE CANADIAN
PRAIRIES OF SASKATCHEWAN IS SHOWN TO DIVE SOUTHEAST INTO THE GREAT
LAKES REGION AND EMERGE INTO THE EASTERN CONUS TROUGH LATE THIS
COMING WEEKEND.  THIS REINFORCEMENT OF THE EASTERN CONUS TROUGH WILL
ALLOW THE CENTRAL STATES RIDGE TO RETROGRADE BACK WEST ACROSS THE
ROCKY MOUNTAINS SATURDAY INTO SUNDAY.  THE WESTWARD RETROGRADE WILL
BE SHORT-LIVED HOWEVER AS THE BC CLOSED LOW RELUCTANTLY ADVANCES ON
THE PACIFIC NORTHWEST AND FORCES THE RIDGE BACK EAST OVER THE PLAINS
LATE SUNDAY INTO MONDAY.  THUS WITH THE WAFFLING OF THE UPPER
RIDGE...PERIODS OF ACTIVE WEATHER SEEM PLAUSIBLE THIS WEEKEND AND TO
START THE WORK WEEK.  THEREAFTER...PRECIP CHANCES CONTINUE THROUGH
THE EXTENDED PERIOD AS THE REGION IS INFLUENCED BY NORTHWEST
TRANSITIONING TO SOUTHWEST FLOW ALOFT. WHILE AGREEMENT BETWEEN THE
ENSEMBLES AND GLOBAL MODELS CONTINUES TO BE EXCELLENT...THE FINER
DETAILS OF PRECIPITATION TIMING AND LOCATION IS STILL MUDDLED...THUS
YIELDING LOW CONFIDENCE.  STARTING OFF SATURDAY...PRECIPITATION
CHANCES LOOK TO INCREASE AS A FRONTAL BOUNDARY STALLS ACROSS
SOUTHERN NEBRASKA...THERE ARE DIFFERENCES IN THE EVENTUAL LOCATION
OF THE FRONT...ESPECIALLY BETWEEN THE GFS AND NAM...BUT THE GENERAL
CONSENSUS PLACES THE HIGHEST POPS SOUTH OF I80...WILL MAINTAIN THE
SOLID CHANCES THERE.  SUFFICIENT INSTABILITY AND SHEAR WILL BE IN
PLACE FOR STRONG OR SEVERE STORMS WELL INTO THE EVENING HOURS.
SUNDAY...A NORTHERN STREAM DISTURBANCE WILL INTERACT WITH A SURFACE
FRONT TO SPARK OFF ADDITIONAL THUNDERSTORMS.  THE ATMOSPHERE IS
EXPECTED TO BE MODERATELY TO STRONGLY UNSTABLE WITH VERY STEEP
LOW-MID LEVEL LAPSE RATES...LARGE HAIL AND GUSTY WIND WOULD BE
POSSIBLE.  INTO EARLY NEXT WEEK...AS THE UPPER RIDGE AMPLIFIES
ACROSS THE WEST AND BUILDS EAST ADDITIONAL STORM CHANCES WILL BE
POSSIBLE ACROSS WESTERN NEBRASKA DURING THE LATE AFTERNOON/EVENING
HOURS...POSSIBLY SPREADING AS FAR EAST AS HIGHWAY 83 BOTH MONDAY AND
TUESDAY NIGHT.  FOR MID-WEEK...UPPER LEVEL RIDGE WILL BE ATOP THE
PLAINS WITH THE MEAN TROUGH ADVANCING ACROSS THE WESTERN
CONUS...WITH SOUTHWEST FLOW ALOFT AND THE POTENTIAL OF LEE
CYCLOGENESIS...MOISTURE RETURN COULD TARGET WESTERN NEBRASKA...WITH
WIDESPREAD SEVERE WEATHER POSSIBLE.  A QUICK LOOK AT TEMPERATURES
THROUGH THE EXTENDED PERIOD REVEALS NO GREAT DEVIATIONS FROM
CLIMO...WITH HIGHS MAINLY IN THE 80-90S AND LOWS GENERALLY IN THE
50-60S.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 625 AM CDT FRI JUN 14 2013

THUNDERSTORMS IN SOUTH CENTRAL NEBRASKA ARE LIKELY TO DISSIPATE BY
LATE MORNING. THEN...NOT MUCH IS EXPECTED BEFORE LATE AFTERNOON WHEN
STORMS BEGIN DEVELOPING ON A FRONT OVER SOUTH CENTRAL AND SOUTHWEST
NEBRASKA. DURING THE EVENING...THEY WILL MAKE PUSH NORTHWARD TO
ABOUT BBW AND LBF BETWEEN 03Z AND 06Z. AT THIS TIME...WE THINK THAT
THE STORMS WILL JUST REACH THE NORTH PLATTE AREA IN THAT TIME.
THEREFORE...WE WILL USE VCTS UNLESS THERE ARE INDICATIONS THAT THE
RAIN AND HAIL WILL REACH LBF. THE AREAS MOST LIKELY TO HAVE
THUNDERSTORMS ARE SOUTH AND EAST OF AN ONL-TIF-OGA-IML
LINE.


&&

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

$$

UPDATE...TAYLOR
SYNOPSIS...SPRINGER
SHORT TERM...SPRINGER
LONG TERM...JACOBS
AVIATION...SPRINGER