Hail and Damaging Winds in Nebraska, June 17, 2001

SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
221 PM CDT SUN JUN 17 2001

MAIN CONCERN FOR FORECAST IS TSTM CHANCES

MORNING UPPER AIR ANALYSIS PLACED 100KT H3 JET ALONG THE US/CANADIAN
BORDER.  FLOW WAS NEARLY ZONAL WITH WEAK SHORTWAVES EVIDENT ON
ANALYSIS MOVING THROUGH FLOW.  ONE SUCH WAVE HAD TRIGGERED WIDELY
SCATTERED -SHRA/-TSRA EARLIER THIS MORNING.  TEMPS AT H7 WERE
BEGINNING THEIR ASCENT WITH +12C NOTED AT LBF AND DDC.  AT H85 A
MOIST AXIS OF 10C DPS EXTENDED NORTH FROM WEST TX INTO NEB...WHILE
H85 WARM FRONT WAS LOCATED ALONG THE NEB/KS BORDER.  AS OF 18Z...SFC
FRONT HAD LIFTED INTO SOUTHERN NEBRASKA AND KUEX INDICATES -TSRA
DEVELOPMENT NORTH OF FRONTAL BOUNDARY.

ZONE BREAKUP WILL DEPENDENT UPON RADAR PICTURE AT ZONE ISSUANCE
TIME...ALTHOUGH CURRENT THINKING IS WIDELY SCT -TSRA WORDING FOR THE
EVENING NORTH OF BOUNDARY.  WILL CONTINUE TO MONITOR FOR ANY TSTM
ACTIVITY IN THE VICINITY OF THE DRY LINE AS WELL.  OVERNIGHT...
MAJORITY OF TSTM ACTIVITY SHLD REFOCUS FURTHER NORTH...NORTH OF THE
WARM FRONT IN NORTHERN NEBRASKA AND SOUTH DAKOTA.  ETA VERY
AGGRESSIVE WITH LLVL JET OF 70KTS TONIGHT WHICH WILL HELP SUSTAIN
CONVECTION TO THE NORTH.  MCS DEVELOPMENT POSSIBLE IN SOUTH DAKOTA
AND CORFIDI VECTOR MOTION DEPICTS A S/SE TRACK AS LLVL JET
INCREASES...SO WILL CONTINUE WITH POPS FOR NIGHTTIME PERIOD.  GUSTY
SOUTH WIND COMPONENT WILL HOLD UP TEMPS TONIGHT AND WILL STAY ABOVE
GUIDANCE FOR LOWS...CLOSE TO CURRENT FORECAST.

STRONGER SHORTWAVE TRACKING THRU NORTHERN PLAINS WILL ADVANCE A COOL
FRONT INTO WESTERN NEBRASKA BY MONDAY MORNING.  MODELS DIFFER
SLIGHTLY ON TIMING OF FRONT AND DEGREE OF CAPPING ACROSS CWA EARLY
IN THE DAY.  VERY WARM H7 TEMPS OF 15C PROGGED BY ETA.  WENT WITH
COMPROMISE OF ETA/AVN FOR TIMING.  CONVERGENCE ALONG FRONTAL
BOUNDARY...AND COOLING ALOFT WITH TROF AXIS SHLD EFFECTIVELY ERODE
CAP BY MONDAY NIGHT WITH TSTMS DEVELOPING ALONG BOUNDARY.  SE
COUNTIES WILL STAND BEST CHC OF TSTMS BASED ON TIMING OF DYNAMICS
AND WILL INCREASE POPS SLIGHTLY.  SVR STORMS POSSIBLE AS WELL.

SHRA/TSRA MAY LINGER INTO THE MORNING TUESDAY ESP IN THE SE.
BOUNDARY THEN STALLS ACROSS KANSAS TUESDAY...AND REDEVELOPMENT OF
STORMS POSSIBLE IN AFTERNOON.  WILL MAINTAIN POPS IN SOUTHERN ZONES
THRU TUESDAY NIGHT AS UPSLOPE FLOW DEVELOPS AND NEXT H7 TROF AXIS
APPROACHES.  BOUNDARY LOCATION WILL NEED TO BE MONITORED TO ADJUST
POPS N/S THIS PERIOD.

COOL FRONT AND EXPECTED CLOUD COVER TUESDAY WILL KEEP TEMPS BELOW
NORMAL.  SOME CLEARING EXPECTED ACROSS THE NORTH TUESDAY NIGHT WITH
TEMPS DROPPING BACK NR 50.

IN THE EXTENDED...LATEST MRF IS MORE AMPLIFIED IN BUILDING RIDGE
ACROSS THE CENTRAL US BY LATE IN THE WEEK THAN PREVIOUS RUN...AND
THE LATEST RUN IS MORE IN LINE WITH UKMO/ECMWF.  NOGAPS HOWEVER IS
NOT AS AMPLIFIED WITH RIDGE PATTERN SETTING UP BY THE END OF THE
WEEK.  WILL LEAVE CHC SHRA/TSRA IN FCST WEDNESDAY UNTIL SHORTWAVE
PASSES AND FRONTAL BOUNDARY PUSHES FURTHER SOUTH OF CWA.  THEN
GENERALLY DRY REMAINDER OF EXTENDED PERIOD WITH BUILDING RIDGE.

.GID...NONE.

DFAY