Severe Thunderstorm Warning 151, NWS Omaha, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
253 PM CDT SUN JUL 2 2000

THE MAIN FORECAST CONCERN FOR THE NEXT FEW DAYS IS CONVECTION...AS A
SERIES OF WEAK DISTURBANCES RIDE AROUND THE UPPER RIDGE AND
THREATEN TO DESTABILIZE A WARM AND VERY HUMID AIRMASS.

THE SHORT TERM CONCERN IS WHETHER FRONTAL CONVERGENCE ZONE VCNTY FSD
INTO NRN IA WILL BE SUFFICIENT TO PRODUCE TSTMS IN OUR AREA AS IT
HEADS SOUTH THIS EVE AND TONIGHT.  LOW LEVEL CONVERGENCE INCREASES
AND INHIBITION BY WARM DRY LYR 850-700 MB DECREASES TOWARD THE E
AWAY FROM OUR IA COUNTIES.  MESOETA INDICATED LITTLE INHIBITION BY
LATE AFTN...BUT BOTH IT AND THE RUC WERE FAR TO HOT WITH SFC TEMPS.
THESE HAVE BEEN HELD BACK BY CU DEVELOPMENT IN VERY MOIST AIR AOB
850 MB.  I STILL THINK THERE IS A SLIGHT CHC TSTMS THIS EVE AND TNGT
IN NRN AND ERN COUNTIES DUE TO COMBO OF FRONT AND OUTFLOW
BOUNDARIES...BUT THE ETA IDEA OF PCPN LASTING ALL NIGHT AND ENDING
UP IN SERN CORNER NEBRASKA SEEMS OVERDONE GIVEN INHIBITION...LACK OF
FORCING ALOFT...AND DECLINING CAPE AFTER DARK.  HIGH DEW POINTS
WOULD PUT MIN TEMPS A FEW DEG ABOVE MOS.

IF LEFTOVER CONVECTION DOES NOT PROVE TO BE A FACTOR...AS
EXPECTED...MONDAY TEMPS SHOULD BE SIMILAR TO TODAY WITH LOW LEVEL
HUMID FLOW FROM SSE AND TEMPS TOPPING OUT AROUND 90.

NEXT CONVECTIVE THREAT WOULD APPEAR TO ARRIVE IN THE FORM OF ANOTHER
RIDGE RUNNER MONDAY NIGHT.  I BELIEVE ETA IS DOING BETTER IN LIFTING
WEAK BNDRY NORTH AGAIN AS VIGOROUS SFC LOW DEVELOPS OVER MT AND WY.
DO NOT BUY AVN SOLN OF STALLING BNDRY IN SRN ZONES WITH CONTD
CONVECTION ALL DAY.   AS UPPER RIDGE BUILDS AND BNDRY LIFTS
NORTH...NEXT SYSTEM WOULD APPEAR MORE LIKELY TO DEVELOP OVER SD
SIMILAR TO ETA DEPICTION...BUT WOULD STILL GIVE A SLGT CHC TO NRN
ZONES.  NGM PCPN PATTERN IS FAR TOO BROAD.  THE ORIGINS OF THE SHRTWV
IN THE SWRN U.S. ARE RATHER MURKY...SO CONFIDENCE IN TIMING AND
LOCATION OF SYSTEM ARE LOW.  POOLING OF MOISTURE COULD END UP FIRING
ACTIVITY FURTHER SOUTH INTO UPPER RIDGE OVERNIGHT...BUT FORCING
SHOULD BE MORE EFFECTIVE NORTH OF LOW LEVEL BNDRY.

TUE LOOKS DRY AND A LITTLE HOTTER AS FLOW AT LOW LEVELS VEERS BACK
INTO THE S OR SSW AND THERMAL RIDGE APPROACHES AREA AHEAD OF SFC LOW.
HOLIDAY MAX TEMPS 90 TO 95 SEEM REASONABLE.

IN EXTENDED...RIDGE RUNNERS COULD STILL A CHC TSTMS IN THE NORTH
BEFORE MID LEVEL HEIGHTS REALLY BUILD UP LATE IN THE WEEK.

.OMA...NONE
POLLACK

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-030415-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
504 PM CDT SUN JUL 2 2000

...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA...

STORM SPOTTERS MAY BE NEEDED LATE THIS AFTERNOON OR THIS EVENING IN
EASTERN NEBRASKA OR SOUTHWEST IOWA.  THE MOST LIKELY AREA WILL BE
FROM THE PLATTE RIVER NORTH AND FROM OMAHA AND COUNCIL BLUFFS NORTH.

A WEAK COOL FRONT FROM NORTHEAST OF SIOUX CITY TO GRAND ISLAND WILL
ACT AS THE MOST LIKELY FOCUS FOR THUNDERSTORM DEVELOPMENT.  OTHER
THUNDERSTORMS ARE POSSIBLE BUT WILL BE LESS LIKELY TO PRODUCE
SEVERE WEATHER.

THUNDERSTORMS WILL BE INHIBITED BY A LAYER OF WARM DRY AIR
ALOFT.  IF STORMS DO DEVELOP...THE PRIMARY SEVERE WEATHER THREAT
WILL BE STRONG DOWN BURSTS AND OUTFLOW WINDS.  THE MAIN THREAT WILL
BE THROUGH 11 PM.  THUNDERSTORMS WILL TEND TO MOVE SLOWLY AND
LOCALLY HEAVY RAINS ARE POSSIBLE FROM ANY THUNDERSTORMS ACROSS THE
AREA.

POWERS