Severe Thunderstorm Warning 135, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
226 PM CDT SAT JUL 1 2000

FORECAST PROBLEM WILL BE POPS TONIGHT...

CONVECTION HAS WINDED DOWN OVER GARFIELD AND WHEELER COUNTIES WITH
OUTFLOW BOUNDARIES LAID OUT AND DRYLINE TO BE FOCUS FOR REDEVELOPMENT
OF THUNDERSTORMS LATE THIS AFTERNOON...INTO THE EVENING. SURFACE
DEWPOINTS ARE CURRENTLY IN THE LOW TO MID 50S WEST...RANING INTO
THE MID 70S IN NORTH CENTRAL. WATER VAPOR IMAGERY SHOWS NEXT
SHORTWAVE NOW MOVING INTO CENTRAL COLORADO AND WYOMING.

MODELS ARE SHOWING SOME VARIATIONS THROUGH 24 HOURS AS SHORTWAVE
MOVES THROUGH THE UPPER RIDGE AND ACROSS THE PLAINS TONIGHT INTO
SUNDAY MORNING...THEN ALL SOLUTIONS TEND TOWARD RISING HEIGHTS AND
WARMING MID LEVEL TEMPERATURES OVER THE PLAINS AS THE LONGWAVE TROUGH
DEEPENS OVER THE WEST COAST. AT THE SURFACE AVN/ETA/NGM ALL VARYING
WITH PLACEMENT OF SEMI-STATIONARY FRONT THROUGH THE CENTRAL PLAINS
WITH AVN MOST NORTH. WARMING MID LEVEL TEMPERATURES MAY EFFECIENTLY
PUT A LID ON THUNDERSTORM DEVELOPMENT DURING THE DAY WITH LATE
EVENING AND OVERNIGHT THUNDERSTORMS STILL POSSIBLE. WILL FOLLOW THE
MEAN SOLUTION WITH ETA THE MODEL OF CHOICE IN THE SHORT-TERM THEN AVN
USED BEYOND...WITH THE CONSIDERATION THAT AVN 7H TEMPERATURES ARE
OVERDONE.

THIS EVENING UPPER LEVEL DIVERGENCE WILL INCREASE AS 7H SHORTWAVE
MOVES EAST ACROSS THE PANHANDLE. TEMPERATURES ARE INTO THE MID 90S
WITH THE CONVECTIVE TEMPERATURE AT 97 FOR LBF WITH MODERATE CU
ALREADY VISIBLE OUT THE WINDOW. THIS EVENING THE DRYLINE WILL
MOVE EAST WITH DRIER AIR SURGING INTO THE EXTREME SOUTHWEST. EXPECT
SCATTERED SHOWERS AND THUNDERSTORMS TO FORM WITH THREAT FOR LARGE
HAIL AND DAMAGING WINDS WITH STORMS WHICH DEVELOP EAST OF A LINE FROM
VTN TO LBF THROUGH THE EVENING. PREVIOUS CONVECTION HAS LAID OUT
BOUNDARIES WHICH WILL BE THE FOCUS FOR ADDITIONAL STORM DEVELOPMENT.
TEMPERATURE GUIDANCE CLOSE AND FOLLOWED.

SUNDAY MORNING THE 7H SHORTWAVE WILL MOVE EAST WITH DRYLINE TO
EXTEND SOUTHWEST FROM LOW NEAR ONL. THE SEMI-STATIONARY FRONT WILL
EXTEND NORTHWEST THROUGH NORTHERN NEBRASKA AND SINK SOUTHWEST
DURING THE DAY AS THE 7H RIDGE AXIS MOVES EAST. THE 8H THETA E RIDGE
AXIS WILL ALSO EXTEND FURTHER WEST BY EVENING WITH A WARM AND HUMID
DAY WITH TEMPERATURES INTO THE 90S.

SUNDAY NIGHT THE 7H RIDGE WILL BE EAST OF THE FORECAST AREA WITH
LEESIDE LOWS ALONG THE FRONT RANGE...WHILE SEMI-STATIONARY FRONT
EXTENDS EAST ACROSS SOUTHERN OR CENTRAL NEBRASKA. BOUNDARY LAYER
MOISTURE WILL RETURN WITH POSSIBLE STRATUS DECK FORMING OVERNIGHT IN
UPSLOPE FLOW. NEXT 7H SHORTWAVE MOVES INTO THE WESTERN PANHANDLE BY
MORNING WITH DIVERGENCE ALOFT FOR WIDELY SCATTERED SHOWERS LATE INTO
THE EASTERN PANHANDLE. DEEP MOISTURE WILL BE LACKING WITH ONLY
SHOWERS MENTIONED WEST OF MERRIMAN TO IML LINE. TEMPERATURES SHOULD
BE MAINLY IN THE MID 60S.

THE AVN MODEL IS PROJECTING MUCH WARMER MID LEVEL TEMPERATURES THAN
THE ETA SOLUTION BY MONDAY AND WILL ADJUST DOWNWARD...WITH THE FRONT
LOCATED ALONG THE NEBRASKA AND SOUTH DAKOTA BORDER. THEY BOTH PROJECT
THE 7H SHORTWAVE MOVING EAST WITH MOISTURE AVAILABLE FOR WIDELY
SCATTERED THUNDERSTORM ACTIVITY IN THE AFTERNOON. THE CAP MAY
HOLD OFF CONVECTION UNTIL LATE AFTERNOON WITH WIDELY SCATTERED
SHOWERS AND THUNDERSTORMS POSSIBLE IN NORTH CENTRAL. LITTLE
VARIATION TO OCCUR IN THE TEMPERATURES WITH GUIDANCE FOLLOWED.

IN THE EXTENDED THE 5H RIDGE AXIS MOVES EAST ON TUESDAY...THEN
REBUILDS TO THE WEST ON THURSDAY. THE SOUTHWEST FLOW ALOFT WILL BRING
DRIER AIR INTO THE REGION WHILE THE SURFACE BOUNDARY MOVES EAST
TUESDAY OVERNIGHT INTO WEDNESDAY WITH MID LEVEL TEMPERATURES TO
COOL. THEN AS A SERIES OF UPPER LEVEL DISTURBANCES TRACK NORTHEAST
SCATTERED THUNDERSTORM DEVELOPMENT ON WEDNESDAY AND THURSDAY.
TEMPERATURES INTO THE 90S TUESDAY...THEN NEAR 90 WEDNESDAY AND
THURSDAY. LOW IN THE 60S.

.LBF...NONE

TLK