Severe Thunderstorm Warning 163, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
221 PM CDT MON JUL 9 2001

...FORECAST CHALLENGE WILL BE POPS...

AT 1830Z CONVECTION HAD ENDED ACROSS THE NORTH CENTRAL WITH OUTFLOW
BOUNDARIES DROPPING SOUTHWEST. LINE OF ACCAS JUST SOUTH WITH
ISOLATED CELLS DEVELOPING IN SOUTHERN LINCOLN AND INTO FRONTIER
COUNTIES. 18Z HAND ANALYSIS SHOWED HIGH PRESSURE RIDGING EAST ACROSS
NORTHERN NEBRASKA...WHILE SURFACE TROUGH EXTENDS SOUTHWEST ACROSS
THE DAKOTAS BORDER AND SECOND BOUNDARY TO OUR SOUTH ACROSS KANSAS
WHICH EXTENDS NORTHWEST ALONG THE FOOTHILLS. WATER VAPOR IMAGERY
SHOWING NEXT WAVE MOVING WEST INTO EASTERN COLORADO AND ANOTHER
WAVE MOVING NORTHEAST THROUGH CENTRAL WYOMING. TEMPERATURES ARE INTO
THE LOW 90S WITH DEWPOINTS TO THE LOW 70S WEST TO ANW TO HDE LINE.

MODELS IN GENERAL AGREEMENT WITH LITTLE MOVEMENT OF H5 RIDGE BEYOND
REORIENTATION AND TIMING OF WAVES TO MOVE THROUGH. BLEND OF RUC/ETA
FOR THE SHORT-TERM THEN ETA/AVN USED BEYOND WITH DEVELOPMENT TO
CONTINUE IN THE SOUTHWEST THIS AFTERNOON WHILE A STRONGER WAVE MOVES
INTO THE NORTHWEST THIS EVENING.

TONIGHT GOOD UPSLOPE FLOW BECOMES RE-ESTABLISHED ACROSS THE
WEST AS SURFACE HIGH WEAKENS. WIDELY SCATTERED THUNDERSTORMS TO OCCUR
THROUGH 7 PM CDT IN THE WEST. THEN AS H5 WAVES MOVE EAST OF RIDGE
AXIS CLUSTER OF THUNDERSTORMS TO FORM IN THE SOUTHWEST AND ANOTHER
ENTER THE NORTHWEST...THEN BOTH TO MOVE EAST SOUTHEAST. H85 JET WILL
INCREASE LIFT IN THE SOUTHWEST AFTER 7 PM AS SOUTH WINDS INCREASE TO
35 KNOTS. PRECIPITABLE WATER AMOUNTS REMAIN AT OR ABOVE 1.5 INCHES
WITH SOME AREAS TO RECEIVE HEAVY RAIN WITH MENTION IN ZONE WORDING
TONIGHT. TEMPERATURES CLOSE AND FOLLOWED. POTENTIAL EXISTS FOR
ANOTHER WIND EVENT OVERNIGHT AS COMPLEX EVOLVES AND MOVES SOUTHEAST.

BY MORNING NEXT WAVE ALREADY MOVING NORTHEAST WHICH WILL KEEP A
CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST TUESDAY WITH
SHOWERS EXITING NORTH CENTRAL. TEMPERATURES WILL BE HELD DOWN BY
ONGOING CONVECTION AND CLOUD DEBRIS WITH MOS GUIDANCE FOLLOWED...
ALTHOUGH TEMPERATURES MAYBE EVEN LOWER IN THE SOUTHWEST IF INDEED
ANOTHER ROUND OF SHOWERS IS ONGOING THROUGH THE MORNING.

TUESDAY NIGHT INTO WEDNESDAY LITTLE CHANGE WILL BE SEEN AS THE H5
CENTER REMAINS ACROSS WESTERN OKLAHOMA INTO THE TEXAS PANHANDLE.
THE INFLUX OF MONSOONAL MOISTURE AS RIDGE RUNNERS MOVE ACROSS WILL
KEEP A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST AS THE
SURFACE FRONT SLOWLY SINKS SOUTH.

IN THE EXTENDED A CHANCE OF SHOWERS AND THUNDERSTORMS CONTINUE
ACROSS THE NORTH. THE H5 HIGH CENTER WILL BUILD WEST AS THE RIDGE
AXIS BECOMES MORE POSITIVELY TILTED AND MOVES EAST ACROSS THE HIGH
PLAINS FRIDAY...BEFORE A SHIFT OCCURS SATURDAY WITH A NORTHWEST
FLOW FLOW REESTABLISHING WITH RIDGE RUNNERS TO MOVE SOUTHEAST
FRIDAY NIGHT THROUGH SUNDAY. THE RIDGE AXIS MOVES EAST ON MONDAY
WITH MORE ZONAL FLOW ALOFT MONDAY WITH DRY CONDITIONS THROUGHOUT.
LITTLE CHANGE OCCURS WITH TEMPERATURES AS NO SIGNIFICANT FRONT TO
PUSH THROUGH TO MODIFY CURRENT AIRMASS.

.LBF...NONE.

KECK

NEZ004-022-056-100530-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1200 AM CDT TUE JUL 10 2001

...SEVERE THUNDERSTORM WATCH NUMBER 535 ALLOWED TO EXPIRE...
...SEVERE WEATHER STILL POSSIBLE ACROSS SHERIDAN COUNTY THROUGH 1130
PM MDT...

THE SEVERE THUNDERSTORM WATCH WHICH WAS IN EFFECT FOR SHERIDAN...
GARDEN AND DEUEL COUNTIES HAS EXPIRED AT 11 PM MDT.

HOWEVER...THUNDERSTORMS CONTINUE ACROSS SHERIDAN COUNTY SOME OF WHICH
MAY PRODUCE STRONG WINDS AND LARGE HAIL THROUGH 1130 PM MDT.  SEVERE
WEATHER IS NOT EXPECTED ELSEWHERE OVER THE NEXT SEVERAL HOURS ACROSS
WESTERN AND NORTH CENTRAL NEBRASKA. FOR THIS REASON THE SEVERE
THUNDERSTORM WATCH WAS ALLOWED TO EXPIRE.

AWJ