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000
FXUS63 KLBF 181538
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1038 AM CDT SAT MAY 18 2013

.MESOSCALE DISCUSSION...
ISSUED AT 1019 AM CDT SAT MAY 18 2013

SEVERE THUNDERSTORM POTENTIAL STILL ON TRACK THIS AFTERNOON AND
EVENING. LATEST HAND SFC ANALYSIS HAS A 1004 MB SFC LOW PRESSURE
CENTER TO THE EAST OF LA JUNTA COLORADO...WITH A DRY LINE
EXTENDING SOUTH FROM THE LOW CENTER THROUGH THE TX PANHANDLE AND
WARM FRONT EAST NORTHEAST ACROSS NORTHERN KS. SFC LOW SHOULD LIFT
NORTH TO NEAR GOODLAND BY LATE AFTERNOON...WITH A WARM FRONT
ARCING NORTHEAST INTO SOUTHWEST NEBRASKA. THUNDERSTORMS SHOULD
INITIATE AROUND IMPERIAL AND HAYES CENTER BY MID TO LATE AFTERNOON
ON NOSE OF VERY STEEP LOW LEVEL LAPSE RATES/DRY LINE WHICH WILL BE
PUNCHING INTO FAR SOUTHWEST NEBRASKA. STORMS LIKELY TO BECOME
SUPERCELLS QUICKLY AS THEY MOVE NORTHEAST INTO A VERY TO EXTREMELY
UNSTABLE AND FAVORABLE SHEARED ATMOSPHERE. BACKED WINDS TO THE
SOUTHEAST ARE EXPECTED ACROSS MOST OF SOUTHWEST
NEBRASKA...ENHANCING THE THREAT FOR TORNADO DEVELOPMENT. IN
ADDITION TO THE TORNADO THREAT...VERY LARGE HAIL...POSSIBLE BASEBALL
SIZE OR LARGER...IS EXPECTED. STORMS WILL LIKELY MERGE EARLY THIS
EVENING INTO A COMPLEX AS THEY ADVANCE NORTHEAST TOWARD CENTRAL
AND NORTH CENTRAL NEBRASKA. LARGE HAIL AND DAMAGING WINDS WILL BE
THE MAIN THREATS FROM THE COMPLEX.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SAT MAY 18 2013

THE RAP13 SEEMS TO HAVE THE BEST HANDLE ON THE STRATUS LIFTING NORTH
INTO THE FCST AREA THIS MORNING. IT WAS ALSO THE PREFERRED MODEL FOR
THE SEVERE WEATHER EVENT EXPECTED TO UNFOLD LATE THIS AFTERNOON AND
TONIGHT. THE STRATUS SHOULD BUILD THROUGH THE FCST AREA ALONG AND
WEST OF HIGHWAY 83 THIS AM AND THEN MIX OUT LATE MORNING/EARLY
AFTERNOON.

THE ONGOING TSTMS AND ISOLD SEVERE STORMS SHOULD CONTINUE TO LIFT
NORTH AND EXIT THE FCST AREA BY SUNRISE. THEREAFTER THE RUC PUSHES
MOISTURE AND INSTABILITY FARTHER WEST THAN THE NAM AND SHARPENS UP
THE DRY LINE ACROSS WRN NEB THIS AFTERNOON. ALL THE WHILE
MAINTAINING A STRONG CAP WHICH SHOULD BREAK AROUND 22Z ON THE
DRYLINE. SPC PROVIDED USEFUL INSIGHT INTO THE EVOLUTION OF THIS
EVENT SUGGESTING LARGE/VERY LARGE HAIL AND WIND DAMAGE LATE THIS
AFTERNOON ALONG THE DRY LINE. THE CONVECTIVE COMPLEX MOVES EAST
TOWARD HIGHWAY 83 THIS EVENING. AT THE SAME TIME...LOW LEVEL WINDS
ARE EXPECTED TO BACK AND INCREASE IN SPEED TOWARD SUNSET OR SHORTLY
THEREAFTER ENHANCING THE TORNADO THREAT FOR A FEW HOURS...ROUGHLY
01Z-04Z.

THE ENTIRE SYSTEM OF STORMS WILL CONTINUE TO MOVE NORTHEAST
OVERNIGHT AND EXIT THE FCST AREA BY SUNDAY MORNING.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 305 AM CDT SAT MAY 18 2013

THE MODELS ARE IN RELATIVELY GOOD AGREEMENT REGARDING UPPER
TROUGH APPROACHING THE REGION ON SUNDAY. THE GFS AND ECMWF BOTH
HAVE THE TROUGH CLOSING OFF AND WRAPPING UP OVER SIOUX FALLS AREA
MONDAY THROUGH WEDNESDAY. THIS WILL MEAN COOLER CONDITIONS AND A
BROAD SCALE AREA OF PRECIPITATION POTENTIALLY ON THE BACK SIDE OF
THE LOW. LOOKING CLOSER AT SUNDAY...SEVERE THUNDERSTORMS WILL BE
POSSIBLE DURING THE AFTERNOON IN THE FAR EASTERN FORECAST AREA IN
VICINITY OF THE COLD FRONT ASSOCIATED WITH THE APPROACHING SYSTEM.
ON MONDAY AND TUESDAY...MODELS ARE INDICATING MOISTURE-RICH AIR
WRAPPING AROUND THE LOW PRESSURE SYSTEM INTO PARTS OF CENTRAL AND
WESTERN NEBRASKA. IT APPEARS THAT THE BEST CHANCE FOR
PRECIPITATION WITH THIS SYSTEM WILL BE IN NORTH-CENTRAL NEBRASKA.
HIGHS WILL DIP INTO THE MID 50S TO MID 60S ON MONDAY AND
TUESDAY...BEFORE REBOUNDING TO THE MID 60S TO MID 70S THURSDAY AND
FRIDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 616 AM CDT SAT MAY 18 2013

MVFR CIGS SHOULD ERODE WITH VFR DEVELOPING BETWEEN 17Z-19Z. SEVERE
STORMS COULD BEGIN DEVELOPING ACROSS SWRN NEB VCNTY KIML AROUND
20Z-22Z. STORM ACTIVITY WILL LIFT NORTH AND EAST THROUGH THE
EVENING HOURS. VFR COULD DEVELOP FROM WEST TO EAST BEGINNING
AROUND 03Z IN THE NEB PANHANDLE TO 09Z IN THE EAST SIDE OF THE
FCST AREA.


&&

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

$$

MESOSCALE...TAYLOR
SHORT TERM...CDC
LONG TERM...KNUTSVIG
AVIATION...CDC