Expires:No;;681555 FXUS63 KLBF 252357 AAA AFDLBF AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE NORTH PLATTE NE 657 PM CDT SAT MAY 25 2013 .SYNOPSIS... ISSUED AT 254 PM CDT SAT MAY 25 2013 THE STORM PREDICTION CENTER HAS OUTLOOKED MUCH OF THE FORECAST AREA TONIGHT THROUGH MONDAY AND SUGGESTS SEVERE WEATHER COULD CONTINUE THROUGH TUESDAY. AN UPPER LEVEL LOW CURRENTLY ACROSS THE NORTH PACIFIC WILL MOVE SLOWLY EAST THIS WEEK AND FORM A CUT OFF LOW ACROSS THE NRN PLAINS BY THURSDAY. THIS WILL DRIVE A PACIFIC COLD FRONT THROUGH THE FORECAST WEDNESDAY. SEVERE WEATHER IS EXPECTED ALONG AND AHEAD OF THIS FRONT. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 254 PM CDT SAT MAY 25 2013 TONIGHT...STILL WATCHING TWO AREAS FOR CONVECTION TONIGHT...THE FIRST ACROSS SOUTHWEST NEBRASKA IN THE VCNTY OF THE DRYLINE WHERE THE DEW POINT GRADIENT IS BEGINNING TO INCREASE ACROSS NORTHEAST COLORADO. THIS AREA DEPICTED FAIRLY WELL BY THE NAM AND OTHER SHORT TERM MODELS. MID AFTERNOON SURFACE HAND ANALYSIS STILL SHOWS THOUGH THAT THE DRYLINE IS FAIRLY DIFFUSE EXCEPT ACROSS SOUTHEAST WYOMING...THEN SOUTHWARD INTO NORTHERN AND EAST CENTRAL CO. IN ADDITION...SIGNIFICANT EML EXISTS EAST OF THE DRYLINE AND THE FEW CU THAT HAVE DEVELOPED INDICATE THAT. SPC MESOANALYSIS SHOWS ONLY WEAK MOISTURE CONVERGENCE IN THE LOW LEVELS AND WEAK PRESSURE FALLS TO THIS POINT...DUE TO THE LACK OF A WELL DEFINED UPPER DISTURBANCE. DO BELIEVE AS THE DRYLINE CONTINUES TO MIX EWD THE CIRCULATIONS ASSOCIATED WITH THE DRYLINE SHOULD ALLOW AT LEAST ISOLATED TSRA TO DEVELOP. ALTHOUGH BEST DEEP LAYER SHEAR WILL BE FURTHER NORTH...VERY GOOD INSTABILITY EXISTS EAST OF THE DRYLINE SHOULD EML BE OVERCOME AND THEREFORE A SVR THREAT DOES EXIST FOR ERN PANHANDLE AND PORTIONS OF THE SOUTHWEST. THE 2ND AND BETTER FORCED AREA OF CONCERN IS WITH THE WARM FRONT THAT HAS BECOME ESTABLISHED ACROSS THE SANDHILLS...CLOSE TO THE HIGHWAY 2 CORRIDOR OR NORTH OF A LINE FROM KBBW TO MERRIMAN. MESOANALYSIS INDICATES THIS AREA HAS BETTER MOISTURE CONVERGENCE/POOLING TO THE NORTH OF THE FRONT AND BETTER DEEP MOIST CONVERGENCE ALONG WITH DEEP LAYER SHEAR. SOME CAP STILL EXISTS IN THIS AREA AS WELL THOUGH WITH THE BETTER LARGE SCALE ASCENT SUGGESTED IN THIS AREA WOULD EXPECT TO SEE SOME DEVELOPMENT IN THIS AREA AS WELL. VISIBLE SAT PICS SHOWS BROAD CU FIELD ACROSS NORTH CENTRAL NEBRASKA SO BETTER THETA-E /DEEPER MOISTURE/ LOCATED NORTH OF WARM FRONT. MCS POTENTIAL BEST HERE OVERNIGHT AS CONVECTION THAT DEVELOPS FURTHER W SHOULD MOVE EAST THEN SOUTHEAST AS LLJ DEVELOPS AFTER SUNSET. FOR SUNDAY...LOW CLOUDS WILL BE A CONCERN GENERALLY EAST OF A LINE FROM LBF TO VTN WHERE MAIN MCS OUTFLOW BOUNDARY SHOULD SETTLE. THIS WILL TAKE AWHILE TO BURN OFF IN THE MORNING...BUT DO EXPECT ANOTHER ROUND OF TSRA DEVELOPMENT BY LATE AFTERNOON ACROSS THE WESTERN PORTION OF THE AREA AFTER ATMOSPHERE RECOVERS WITH STRONG INSOLATION BY EARLY AFTERNOON. WARM FRONT/BOUNDARY SHOULD BE LOCATED FURTHER WEST SUNDAY AFTERNOON AND THEREFORE BEST MCS CHANCES FURTHER WEST AS WELL. AFTERNOON MAX TEMPS WILL BE DEPENDENT ON CLOUD COVER AGAIN...BUT GENERALLY 80S TO NEAR 90 IN FAR SOUTHWEST...WEST OF WHERE MORNING CLOUDS WILL EXIST. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 254 PM CDT SAT MAY 25 2013 SFC LOW PRESSURE WILL REMAIN TUCKED ACROSS ERN COLO. BOUTS OF THUNDERSTORMS ACROSS THE FCST AREA...SOME SEVERE...WILL CAUSE THE LOW TO MOVE EAST INTO WRN KS. ONCE THE CONVECTION WEAKENS THE LOW SHOULD REESTABLISH ITSELF FARTHER WEST ACROSS THE COLO PLAINS. WINDS ALOFT AT 500 MB REMAIN WEST SOUTHWEST AND STEADY AT 20 TO 30 KTS. WITH THE SFC LOW ACROSS ERN COLO LOW LEVEL WINDS ARE EAST AND SOUTHEAST WHICH THEN VEER TO SOUTH AT 850 MB. THUS SHEAR IS FCST TO REMAIN MODEST TO STRONG AT TIMES AND WHEN COMBINED WITH MLCAPE REACHING AROUND 3500 DAILY...CONDITIONS SHOULD REMAIN FAVORABLE FOR SUPER CELL DEVELOPMENT THROUGH TUESDAY. THE MODEL CONSENSUS ALSO SHOWS THE SFC LOW DEEPENING TO AROUND 992-995 MB BY TUESDAY AFTERNOON. THE NAM WAS THE DEEPEST AT 986 MB. THIS WOULD SUPPORT MORE FOCUS IN THE SFC DEW PTS AND A SHARPENING UP OF THE DRYLINE WHICH COULD BE THE FOCUS FOR STORM DEVELOPMENT ACROSS SWRN NEB. THE MODELS GENERALLY SHOW A TRIPLE POINT SETTING UP DAILY ACROSS NWRN KS. THE MODELS SHOW A SIGNIFICANT SHORT WAVE MOVING THRU NRN COLO WEDNESDAY AFTN/EVENING SUPPORTING STORM CHANCES ACROSS THE FCST AREA LATE IN THE DAY OR AT NIGHT. A DISTURBANCE WILL EMERGE OFF THE COLO ROCKIES MONDAY AND THE MODELS STEER THIS DISTURBANCE INTO WRN KS AND SWRN MONDAY NIGHT. TEMPERATURES ARE A BLEND OF VARIOUS MODEL DATA PLUS BIAS CORRECTION FOR HIGHS IN THE 80S MONDAY. BY TUESDAY THE SFC LOW SHOULD PULL COOL AIR INTO NWRN NEB FOR HIGHS IN THE UPPER 70S NORTHWEST TO MID 80S SOUTH. TUESDAY NIGHT THROUGH SUNDAY MORNING... THE MODELS ARE ARE IN REASONABLE AGREEMENT THAT A CLOSED UPPER LEVEL LOW WILL DRIFT THROUGH THE NRN PLAINS AND SEND A PACIFIC COLD FRONT THROUGH THE FCST AREA WEDNESDAY AND BEYOND. H700 MB TEMPS FALL FROM 12C TO AROUND 3C AND MAX TEMPS FALL FROM THE 70S AND 80S WEDNESDAY TO THE UPPER 60S TO MID 70S BY SATURDAY. WITH THE COLD POOL ALOFT IMPINGING ON THE FCST AREA...THUNDERSTORMS ARE POSSIBLE THROUGHOUT THE FCST. A LOBE OF UPPER LEVEL ENERGY ASSOCIATED WITH THE PACIFIC COLD FRONT MOVES THROUGH WEDNESDAY PRODUCING SCATTERED TSTM COVERAGE. COLD AIR ALOFT AND THE PACIFIC FRONT SHOULD DO THE SAME THURSDAY. RAIN CHANCE DECREASE FRIDAY AND SATURDAY SOUTH BUT CONTINUE ACROSS THE NORTH WHERE THE COLD POOL WILL CONTINUE TO OPERATE DESTABILIZING THE ATMOSPHERE. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 656 PM CDT SAT MAY 25 2013 VFR CONDITIONS WILL CONTINUE THROUGH THE EARLY EVENING OVER MOST OF WESTERN AND NORTH CENTRAL NEBRASKA. THERE ARE ISOLATED THUNDERSTORMS MOVING TO THE NORTHEAST IN THE NORTHERN NEBRASKA PANHANDLE AND A CLUSTER OF STORMS OVER SOUTHWEST NEBRASKA BETWEEN HAYES CENTER AND CURTIS. THESE STORMS ARE MOVING TO THE NORTHEAST TOWARDS SOUTHERN LINCOLN COUNTY AND SOUTHERN CUSTER COUNTY. STILL A CAP IN PLACE OVER MUCH OF WESTERN NEBRASKA. STRONGER WAVE TO PUSH ACROSS WESTERN NEBRASKA AFTER 2606Z. THIS IS WHEN THUNDERSTORMS SHOULD BECOME MORE WIDESPREAD THROUGH 2612Z. STRATUS TO BUILD IN THROUGH THE EARLY MORNING BEHIND THE THUNDERSTORMS. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CDC SHORT TERM...JWS LONG TERM...CDC AVIATION...POWER