Severe Thunderstorm Warning 31, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
142 PM CDT SAT MAY 5 2001

...PINPOINTING THE AREA OF POSSIBLE SVR WEATHER TONIGHT AND HIGH
TEMPS THE NEXT COUPLE OF DAYS WILL BE THE CONCERNS...

SATELLITE WATER VAPOR IMAGERY INDICATES THE UPPER LOW TO BE OVER
EASTERN CO WITH SHORTWAVES WRAPPING AROUND THE SYSTEM. VISIBLE
SATELLITE IMAGERY SHOWS THE DRY PUNCH PUSHING ALL THE WAY NORTH
INTO NORTH CENTRAL NE. THE FINER RESOLUTION ETA MODEL HANDLES THIS
WELL. WHEN COMPARING THE SHORTWAVE PLACEMENT ON THE WATER VAPOR
IMAGERY WITH THE ETA...IT SEEMS TO BE TRACKING THESE QUITE WELL SO
WILL GENERALLY LEAN TOWARD THE ETA WITH THIS FORECAST PACKAGE.

TEMPERATURES IN THE DRY SLOT SHOULD WARM UP ENOUGH THIS AFTERNOON...
INTO THE LOWER 60S...TO CREATE AN UNSTABLE ATMOSPHERE.  THE UPPER
LOW WILL SWING INTO SOUTHWEST NE THIS EVENING AND THEN BECOME
NEGATIVELY TILTED AS IT PUSHES INTO SOUTH CENTRAL NE OVERNIGHT.  A
GOOD AREA OF H7 FRONTOGENESIS TAKES PLACE ACROSS THE NORTHWEST PART
OF THE CWA EARLY THIS EVENING.  THIS COINCIDES WITH UPPER DIVERGENCE
IN THE LFQ OF THE JET STREAK SWINGING AROUND THE UPPER LOW. ALTHOUGH
SFC TEMPS WILL CONTINUE TO BE COOL...THERE IS A CHC OF ELEVATED
CONVECTION SO WILL INCLUDE THUNDERSTORMS.  THIS AREA SHOULD ROTATE
NORTHWESTWARD OUT OF THE CWA LATER THIS EVENING.  ANOTHER SHORTWAVE
SWINGS INTO THE SOUTHEASTERN PORTION OF THE CWA THIS EVENING WHICH IS
ALSO ACCOMPANIED BY UPPER DIVERGENCE IN THE LFQ.  LOW LEVEL WAA
DEVELOPS HERE AS A SFC LOW FORMS IN SOUTHWEST NE.  THIS AREA LIKELY
HAS THE BEST CHC OF SVR WEATHER AS CAPES REACH 700 J/KG THIS EVENING.
THIS WILL SPREAD INTO THE NORTHEAST PART OF THE CWA OVERNIGHT. EXPECT
LIGHT RAIN TO CONTINUE ACROSS THE WEST OVERNIGHT AS THE DEFORMATION
ZONE SWINGS INTO THE AREA.  WITH THE LOW CLOUDS AND PRECIP...EXPECT
LOW TEMPS TONIGHT TO REMAIN IN THE 40S WEST TO THE MID 50S EAST.

CLOUDS AND RAIN WILL LINGER SUN MORN IN THE WEST AS THE DEFORMATION
ZONE REMAINS IN THE AREA BUT SWINGING INTO THE EAST BY AFTERNOON WITH
SKIES BECOMING MOSTLY SUNNY IN THE NORTHWEST. NORTHWEST DOWNSLOPE
FLOW AND SUN WILL KEEP THE TEMPS FAIRLY MILD BUT WINDY CONDITIONS
WILL MAKE IT FEEL CHILLY.  LIGHT RAIN WILL FINALLY COME TO AN END IN
THE EAST BY MID AFTERNOON AS WAA SHUTS OFF AND UPPER DIVERGENCE MOVES
OUT OF THE AREA. SKIES WILL CONTINUE TO CLEAR FROM NORTHWEST TO
SOUTHEAST ACROSS THE CWA TOMORROW NIGHT. A TIGHT PRESSURE GRADIENT
WILL KEEP WINDS FROM DECOUPLING AND TEMPS BOTTOMING OUT.  WILL FOLLOW
CLOSE TO THE FAN/FWC NUMBERS FOR LOWS. MOSTLY SUNNY SKIES AND
WESTERLY DOWNSLOPE WINDS WILL ALLOW TEMPS TO WARM TO NEAR NORMAL ON
MON.  A TIGHT TEMP GRADIENT OVER THE NORTH WILL KEEP WINDY CONDITIONS
AROUND YET MON. DRY CONDITIONS CONTINUE MON NIGHT AS SFC HIGH
PRESSURE DOMINATES THE AREA.

IN THE EXTENDED...A WEAK UPPER RIDGE BUILDS OVER THE AREA TUE INTO
WED KEEPING CONDITIONS DRY.  THE FLOW BECOMES ZONAL WITH WEAK WAVES
SLIDING THROUGH THE AREA THU THROUGH SAT.  ONE WAVE COMES THROUGH THU
AND ANOTHER ONE SAT WHICH SHOULD BRING A CHC OF SHOWERS. FRI LOOKS
DRY FOR NOW AS A SFC HIGH MOVES INTO THE AREA. H8 TEMPS SUGGEST THE
WARMEST DAYS TO BE WED AND THU. HOWEVER NORTHEAST WINDS AND MORE
CLOUDS ON THU SHOULD KEEP TEMPS A LITTLE COOLER.

.LBF...NONE.

DDB