Damaging Wind in Nebraska, July 26, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
237 PM CDT FRI JUL 26 2002

...FORECAST CHALLENGE TO BE WHETHER TO INCLUDE ISOLATED IN THE WEST
TONIGHT...TEMPS...AND TIMING OF FRONT AND WAVE ON SUNDAY...

18Z WV IMAGERY VERIFIES POSITION OF VORT MAX IN NWRN WY WHICH IS
ALSO INDICATED BY THE ETA AND AVN. THE AVN HAS DONE A BETTER JOB WITH
POSITION OF PRECIP IN SERN NEBR AND KEEPING AREA DRY FROM NW UT/SWRN
WY. DESPITE APPROACH OF UPPER TROUGH AND VORT MAX...BULK OF UPPER
SUPPORT WILL REMAIN TO OUR NORTH IN LEFT EXIT REGION OF UPPER JET
AND ALONG AND EAST OF SFC TROUGH. SECOND AREA WILL REMAIN TO OUR
SOUTHEAST NEAR SFC BOUNDARY AND RIGHT ENTRANCE REGION OF UPPER JET
ACROSS WISC AND NRN IND. META POINT SOUNDING FOR IML SHOWS
SIGNIFICANT DRYING BELOW 700MB. NO DIRECTIONAL SHEAR WITH ONLY SOME
SPEED SHEAR. A LOOK AT WV IMAGERY AT 19Z SHOWED VORT MAX NORTH OF
KCOD ON NWRN WY WITH  WDLY SCT CONVECTION APPROACHING RAWLINS AND CASPER.
AVN/ETA AGREEING IN WEAK SFC HIGH PRESSURE ACROSS THE CWFA THROUGH
THIS EVENING AND LACK OF ANY FRONTAL BOUNDARY. HOWEVER DUE TO FAST
MID AND UPPER ZONAL FLOW AND APPROACH OF DPVA AHEAD OF VORT MAX WILL
INCLUDE ISOLATED -TRW INTO THE WESTERN TIER OR TWO OF CWFA BEFORE
DYING OF BY AROUND SUNSET. TO THE EAST WILL REMOVE THE 20 TO 30
POPS.

SATURDAY/SATURDAY NIGHT CONTINUE TO LOOK DRY IN ADVANCE OF
APPROACHING WAVE CURRENTLY MOVING THROUGH WA/NWRN OR. SFC PRESSURE
FALLS OCCUR FROM THE NRN INTO CNTRL ROCKIES WHILE H5 FALL OCCUR AS
FAR EAST AS MT NW WY. H85 THERMAL RIDGE STRENGTHS FROM THE HIGH
PLAINS OF NM/WEST TX NORTH INTO NERN CO/SWRN NEBR. MOSTLY SUNNY WITH
WRLY DOWNSLOPE WINDS TO AID WARMUP. HIGHS OF LOWER 90S NORTHWEST TO
NEAR 100 FRONTIER COUNTY LOOK LIKELY.

SUNDAY...AVN AND ETA DISAGREE ON POSITION OF SFC FRONT AND TIMING OF
UPPER WAVE. THE AVN IS ABOUT 6 HRS FASTER WITH UPPER TROUGH AND IS
MUCH FARTHER SOUTHEAST WITH SFC BOUNDARY. THE ETA ACTUALLY DEEPENS THE
SFC TROUGH TO THE WEST DURING THE DAY AND POSITIONS IT FROM NEAR ONL
TO GLD KS. THIS SCENARIO WOULD LIKELY KEEP LOWEST POPS NORTHWEST OF
VTN TO IML WITH HIGHER POPS TO THE SOUTHEAST WHERE AFTN CAPES SHOULD
RANGE FROM AT LEAST 1000-1500 J/KG. AFTN HIGH TEMPS DIFFICULT TO
DETERMINE DEPENDING ON POSITION OF SFC BOUNDARY. FAVORING THE ETA
HIGHS INTO THE UPPER 90S EAST OF ANW TRENDING TO LOWER 90S
NORTHWEST. LIMITING FACTOR FOR TSRA DEVELOPMENT WILL BE LACK OF
MOISTURE BELOW H7 BUT WITH INVERTED-V TYPE SOUNDING AND WEAK
DIRECTIONAL SHEAR BELOW H7...DMG WIND POSSIBLE WITH ANY STORMS
WHICH DO DEVELOP. CHC TO CONTINUE OVER THE EAST INTO THE EVENING.

MONDAY/MONDAY NIGHT...AS UPPER TROUGH EXITS A BIT COOLER AIR WILL BE
DRAWN DOWN INTO THE CENTRAL PLAINS. H85 TEMPS WILL BE ABOUT 2C
COOLER AND WILL TRIM DOWN HIGHS ABOUT 5 DEGREES.

EXTENDED...UPPER RIDGE FCST TO BUILD NORTHEASTWARD INTO THE CENTRAL
PLAINS TUE-FRI. ALTHOUGH A NOCTURNAL RIDGE RUNNER MCS CANNOT BE
RULED OUT ACROSS THE NORTH...WILL LEAVE EXTENDED DRY. TEMPS ABOVE
SEASONAL NORMALS WITH HIGH TEMPS INCREASING A COUPLE OF DEGREES EACH
DAY ON WED AND THU.

.LBF...NONE

KAR