Severe Thunderstorm Warning 121, NWS Hastings, NE

SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
212 PM CDT MON JUN 10 2002

FRONTAL MOVEMENT AND ASSOCIATED WEATHER MAIN CONCERN TODAY.

18Z SURFACE ANALYSIS SHOWS FRONT HAS ENTERED THE NW CWFA. KUEX SHOWS
IT BETWEEN KLXN AND KEAR.  KUEX ALSO SHOWS A CONVERGENT AREA JUST
WEST OF THE RADAR IN FRANKLIN COUNTY.  EXPECT STORMS TO FIRE ON THE
FRONT OR AS THESE BOUNDARIES MERGE 20Z-21Z. BY THAT TIME CONVECTIVE
TEMPS SHOULD BE REACHED.

GID CWFA IS IN BETWEEN VERY CAPPED OFF SOUNDING AT KLBF THIS MORNING
AND NO CAP AT KOMA.  SHOULD BE SUFFICENT TO HOLD STORMS OFF UNTIL
EXPLOSIVE DEVELOPMENT CAN TRANSPIRE.

PRESSURE RISES BEHIND THE FRONT DECREASING A BIT AND WINDS BECOMING
MORE NNE VS NW SUGGESTING WESTERN SIDE OF FRONT SLOWING DOWN.  THIS
IS CONSISTENT WITH PROGS SHOWING FRONT HANGING UP JUST SOUTH OF CWFA
TONIGHT AS LOW PRESSURE DEVELOPS IN KS.  THIS SHOULD LEAD TO BETTER
LOW LEVEL SHEAR WHICH WILL ENHANCE TORNADO THREAT ALREADY IN EXISTENCE
ALONG ALL BOUNDARIES TODAY DUE TO AMOUNT OF INSTABILITY
PRESENT...WHICH SHOULD TOP OUT BETWEEN 3 AND 4 KJ/KG.

STORMS SHOULD SUSTAIN OVERNIGHT WITH DIFLUENT UPPER FLOW AND FORCING
NEAR BOUNDARY.  AMOUNT OF MOISTURE WILL BE CONDUCIVE TO VERY HEAVY
RAINFALL AND SOME TRAINING POSSIBLE LATER TONIGHT IN DIFLUENT
THICKNESS AREA AS FRONT LAYS OUT EAST/WEST.  WILL NOT ISSUE FFA
TONIGHT AS ANTECEDENT CONDITIONS FAIRLY DRY. EXCEPTION WOULD BE
PARTS OF MITCHELL COUNTY WHICH RECEIVED 1-2 INCHES OF RAIN THIS
MORNING.

LIFT AND THUS THUNDERSTORMS SHOULD PERSIST INTO TUES MORNING.
BOUNDARY MAY STILL BE HUNG UP IN SE CWFA OR MOVE BACK NORTH IN THE
AFTERNOON.  EITHER WAY IT APPEARS THAT STORMS COULD FIRE UP AGAIN IN
THE AFTERNOON THERE AND EXPAND NORTHWARD OVERNIGHT AS LLJ THROWS
MOISTURE BACK NORTH OF FRONT.  FLASH FLOOD WATCH MAY BE NEEDED TUES
NIGHT IF RAINS PAN OUT TONIGHT AND HVY QPF PROGS OF ETA STILL HAVE A
CHANCE TO MATERIALIZE TUES NIGHT.  AGAIN...STORMS COULD PERSIST INTO
WED MORNING.

TEMPS WILL BE TRICKY WITH BOUNDARY AND ROUNDS OF CONVECTION. HAVE
TRENDED A BIT TOWARD HIGHER ETA DEW POINTS AND THUS WARMER LOW
TEMPERATURES.  ALSO HAVE WENT A BIT WARMER IN THE DAYTIME WITH A
SLIGHTLY FARTHER NORTHWARD FRONTAL POSITION.

HAVE INSERTED A CHANCE FOR TSTMS NW CWFA WED EVENING AS MID LEVEL
SHORT WAVE INDUCED SURFACE TROUGH ACROSS NW NEBR ENHANCES MOISTURE
CONVERGENCE UNDER COOL TEMPS ALOFT.   HAVE ALSO INTRODUCED A CHANCE
FOR STORMS SUNDAY NIGHT IN RETURN FLOW AFTER A FEW DAYS OF HIGH
PRESSURE AND LOWER HUMIDITIES.

.GID...NONE.

DROZD

KSZ005>007-017>019-NEZ039>041-046>049-060>064-072>077-082>087-111200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HASTINGS NE
422 PM CDT MON JUN 10 2002

...SPOTTER ACTIVATION WILL BE NEEDED THIS EVENING ACROSS NORTH
CENTRAL KANSAS AND PARTS OF SOUTH CENTRAL NEBRASKA...

THUNDERSTORMS WILL DEVELOP ALONG A SLOW MOVING COLD FRONT ACROSS
SOUTH CENTRAL NEBRASKA AND NORTH CENTRAL KANSAS THIS EVENING.
STORMS ARE EXPECTED ALONG AND EAST OF A LINE FROM ST PAUL NEBRASKA
TO PHILLIPSBURG KANSAS.  THE STORMS WILL QUICKLY BECOME SEVERE WITH
THE PRIMARY THREAT BEING LARGE HAIL AND DAMAGING STRAIGHT LINE
WINDS...HOWEVER THE THREAT OF TORNADOS EXISTS AS WELL.

INDIVIDUAL STORM MOVEMENT WILL BE NORTHEAST AT 20 TO 25 MPH...WHILE
THE ENTIRE STORM AREA GRADUALLY SHIFTS SOUTHEAST THROUGH SOUTH
CENTRAL NEBRASKA AND NORTH CENTRAL KANSAS AS THE EVENING PROGRESSES.
HEAVY RAIN WILL ALSO ACCOMPANY THE STORMS THROUGH TONIGHT...AND SOME
LOCALIZED FLOODING WILL BE POSSIBLE.

AN UPPER LEVEL DISTURBANCE MOVING INTO THE AREA TONIGHT WILL BRING
THE CHANCE OF THUNDERSTORMS TO ALL OF SOUTH CENTRAL NEBRASKA AND
NORTH CENTRAL KANSAS DURING THE OVERNIGHT HOURS.

EMERGENCY MANAGERS AND STORM SPOTTERS SHOULD BE READY FOR ACTIVATION
THIS EVENING.

FAY