Severe Thunderstorm Warning 259, NWS Goodland, KS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
224 PM MDT MON AUG 20 2001

FORECAST CHALLENGES INCLUDE TEMPS AND PRECIP CHANCES.

18Z SURFACE MAP ANALYSIS SHOWED A WARM FRONT EXTENDING FROM A
SURFACE LOW OVER SOUTHEAST COLORADO EXTENDING EASTWARD ACROSS
SOUTHERN KANSAS WITH A SECONDARY WARM FRONTAL BOUNDARY FROM A LOW
NEAR DENVER EXTENDING EASTWARD ACROSS GOODLAND TO NEAR HAYS KANSAS.
IR AND WATER VAPOR SATELLITE IMAGERY SHOWED AN IMPRESSIVE S/W
ROTATING IN SOUTHEAST UTAH WITH UPPER RIDGE ANCHORED OVER TEXAS AND
OKLAHOMA.

MODELS HAVE NOT BEEN IN GOOD AGREEMENT LATELY. HOWEVER THE ETA
MODEL HAS BEEN MORE CONSISTENT FROM RUN TO RUN. THIS HAS
BEEN ESPECIALLY TRUE WITH POSITION AND TIMING OF UPPER LEVEL S/W
IMPULSES ACROSS THE CENTRAL HIGH PLAINS AROUND THE PERIFERY FLOW
AROUND THE UPPER RIDGE. AVN AND NGM INITIALIZED TOO STRONG WITH UPPER
SYSTEM OUT WEST. TEMPS WERE BETTER HANDLED BY ETA WITH AVN TOO COOL.

TONIGHT KAIN FRITSCH AND ETA MODELS BOTH DEPICT GOOD MID LEVEL
MOISTURE FLOWING NORTHEAST ACROSS EASTERN COLORADO INTO SOUTHWEST
NEBRASKA ZONES RESULTING IN BEST CHANCE FOR STORMS. WILL GO 30 POPS
WEST AND NORTH WITH 20 POPS FURTHER EAST WITH NO PRECIP FAR EASTERN
ZONES. WILL GO CLOSE TO GUIDANCE TEMPS OVERNIGHT RANGING FROM UPPER
50S WEST TO LOWER 60S EAST.

FOR TUESDAY EXPECT SUBSIDENCE DURING THE DAY FROM WEST TO EAST
ACROSS CWA FOLLOWING MONDAY NIGHT S/W. UPPER RIDGE SEEMS TO FLATTEN
A BIT AS WELL. TEMPS WILL AGAIN BE A CHALLENGE. MONDAY TEMPS WERE
CONSIDERABLY HIGHER THAN GUIDANCE. LOOKS LIKE A REPEAT OF MONDAY.
WILL GO ABOVE GUIDANCE TEMPS WITH HIGHS GENERALLY 90 TO 95 MOST
AREAS. WILL NOT CARRY PRECIPITATION CHANCES DURING THE DAY EXPECT
20 POPS FOR THE AFTERNOON OVER EASTERN COLORADO.

FOR TUESDAY NIGHT ANOTHER SIGNIFICANT 5H S/W MOVES ACROSS REGION IN
WESTERLY UPPER FLOW. MODELS PROG SUFFICIENT MID LEVEL MOISTURE AS
WELL AS INSTABILITY FROM DAYTIME HEATING TO RESULT IN SCATTERED
CONVECTION. WILL CARRY MOSTLY CLOUDY SKIES WITH CHANCE POPS ALL
ZONES. OVERNIGHT TEMPS WILL CONTINUE CLOSE TO GUIDANCE IN THE 60S.

FOR WEDNESDAY INTO WEDNESDAY NIGHT LITTLE CHANGE IN OVERALL SURFACE
AND UPPER AIR PATTERN. ANOTHER WAVE IS PROGGED TO MOVE EASTWARD IN
UPPER FLOW OUT THE GREAT BASIN AREA. WILL GO WITH LOW CHANCE POPS
MAINLY LATE AFTERNOON ACROSS MOST OF AREA WITH 30 POPS OVERNIGHT.
WILL AGAIN GO ABOVE GUIDANCE FOR TEMPS MOSTLY AROUND 90 MOST AREAS.
SOUTH TO SOUTHWEST SURFACE WINDS WILL CONTINUE TO WARM THE
ATMOSPHERE.

WILL MAKE NO CHANGES TO THE EXTENDED FORECAST. MRF AND ECMWF RUNS
NOT IN BEST OF AGREEMENT. DIFFERENCES EXIST IN TIMING OF UPPER LEVEL
WAVES THROUGH UPPER LEVEL FLOW. STILL SEE SUFFICIENT MOISTURE TO
RESULT IN CHANCES FOR THUNDERSTORMS THROUGHOUT ENTIRE EXTENDED
PACKAGE. TIMING WILL BE THE ONLY BIG CHALLENGE. TEMPS STILL LOOK
GOOD.

.GLD...NONE.

LAMMERS