Severe Thunderstorm Warning 90, NWS Goodland, KS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
229 PM MDT SUN AUG 4 2002

FORECAST PROBLEMS WILL BE CHANCE OF PRECIPITATION IN THE SHORT TERM
AND WHAT DO WITH THE EXTENDED.

SATELLITE CONTINUING TO SHOW AMPLIFIED PATTERN FROM CENTRAL PACIFIC
INTO NORTH AMERICA. UPPER TROF CONTINUES TO DEEPEN ALONG THE WEST
COAST. SHORTWAVE INDICATED ON SATELLITE/UPPER AIR ANALYSIS OVER
WYOMING AND COLORADO. SUBTROPICAL MOISTURE PLUME STILL STREAMING
OVERHEAD. MAIN COLD AIR/FRONT REMAINS WELL NORTH OF AREA WITH
TROF/WEAK FRONT DIVIDING THE CWFA INTO A NORTHWEST AND SOUTHEAST
HALF. AT JET LEVEL...MODELS MISSED JET MAX OVER IDAHO WITH ETA
CATCHING IT THE BEST AND THE AVN THE WORST. OTHERWISE MODELS DID
WELL. AT MID LEVELS...AVN INITIALIZED A LITTLE BETTER WITH HEIGHTS.

AT 850 MB/SURFACE...AS HAS BEEN THE CASE THE MODELS HAVE INITIALIZED
TOO COOL OVER MOST LOCATIONS. THEY ALSO APPEAR TO HAVE THE EASTERN
END OF MAIN FRONTAL BOUNDARY TOO FAR SOUTH. ETA/NGM ARE TOO DRY
WHILE AVN IS TOO WET. ON FEATURES/POSITION...AVN LOOKS TO BE DOING
A LITTLE BETTER THAN THE ETA OVER OUR AREA. WILL BLEND ETA/AVN FOR
TONIGHT AND THEN GO TO THE ETA FOR THE REST OF THE PACKAGE BASED ON
ABOVE FACTORS...RECENT PERFORMANCE...AND PERSISTENCE.

FOR TONIGHT...AS OF 18Z...THUNDERSTORMS HAVE ALREADY STARTED FIRE
OFF THE FRONT RANGE OF COLORADO. CU FIELD IS STARTING DEVELOP OVER
THE CWFA AT THIS TIME. SETUP LOOKS TO BE VERY SIMILAR TO LAST NIGHT.
GREATEST CHANCE WILL BE NEAR BOUNDARY AND OVER NORTHERN/WESTERN
SECTIONS. WILL AGAIN GRADIENT LOWEST TO HIEST POPS FROM SOUTHEAST TO
NORTHWEST. MOVEMENT OF STORMS WILL SLOWER BE THAN YESTERDAY. MAIN
THREAT WILL BE LOCALLY HEAVY RAINFALL AND SMALL HAIL DUE TO
WARM/SUBTROPICAL AIR MASS ALOFT.

FOR MONDAY/MONDAY NIGHT...QUESTION WILL BE IF CONVECTION THAT
DEVELOPS ON THE MAIN BOUNDARY OVER NEBRASKA TONIGHT WILL DRIVE
THIS FRONT FURTHER SOUTH. OTHERWISE...AVN TAKES BOUNDARY TO OVER THE
EXTREME NORTHERN PORTION OF THE CWFA BY 18Z AND THEN A LITTLE NORTH
OF THE CWFA BY 00Z. ETA HAS IT NORTH OF CWFA BY 18Z. BECAUSE OF
WARM/MOIST AIR MASS...OUTFLOW WAS NOT EXTREMELY COLD/DENSE LAST
NIGHT. CONSIDERING THAT AND RIDGING BUILDING IN ALOFT...LIKE ETA
DEPICTION BETTER AND BELIEVE THERE WILL BE NO BOUNDARY OVER OUR AREA.
ALSO MID/UPPER LEVEL RIDGING WILL DEFLECT SHORTWAVES TO THE NORTH OF
AREA AS THE FLOW ALSO BRINGS IN DRIER AIR AT 500 MB THAT IS TO THE
SOUTH AND EAST OF THE AREA. SO WILL REMOVE PRECIPITATION FROM THIS
PERIOD. WILL RUN WITH ETA ON TEMPS SINCE IT HAS BEEN NEARLY
UNBEATABLE HEAR RECENTLY.

FOR TUESDAY THROUGH WEDNESDAY...RIDGING...DRYING...AND WARMING WILL
PREVAIL. BASED ON JET PROGS...SATELLITE...AND CURRENT PATTERN...
BELIEVE AVN IS TOO STRONG AND COLD TOWARD THE END OF THIS PERIOD...
AND WILL DISCOUNT AT THIS TIME. THIS WILL BLEND IN WELL WITH THE
BEGINNING OF THE 4 TO 7 DAY PERIOD...AND ECMWF AS WELL. WILL
CONTINUE TO GO ABOVE NGM/MAV MOS FOR MAXES AND GO NEAR THE ETA
MOS/2M.

IN THE 4 TO 7 DAY PERIOD...AS OF 12Z MODELS HANDLING FEATURES WELL.
HOWEVER...BY THE TIME THE MODELS GET INTO THIS TIME FRAME...THEY
START DIVERGING CONSIDERABLY FROM EACH OTHER AND THE PREVIOUS RUN.
EACH HAS MAJOR RAMIFICATIONS TO THIS FORECAST. I AM GOING TO LOVE TO
SEE WHAT THE ENSEMBLES/NECP IS GOING TO SAY ON THIS ONE. BASICALLY...
MODELS BREAK DOWN RIDGE/AMPLIFIED PATTERN WITH TIME...AND AT A FASTER
PACE THAN PREVIOUS RUNS. THE MOST AGRESSIVE IS THE GFS WITH THE UKMET
NEXT IN LINE. I AM HAVING A HARD TIME SEEING THIS CONSIDERING WHAT
THE MEAN PATTERN HAS BEEN THIS SEASON...CURRENT AMPLIFIED PATTERN...
AND JET PROGS.

IT IS POSSIBLE THIS DEAMPLIFICATION WILL OCCUR...BUT AT A SLOWER
PACE MORE IN LINE WITH THE ECMWF WHICH HAS BEEN MORE CONSISTENT. THE
GFS LOOKS WAY TOO DEEP/SLOW/COLD EVEN IF WHAT IT IS ADVERTISING TAKES
PLACE. BELIEVE WHEN SYSTEM NEAR WEST COAST KICKS OUT...IT WILL GO
FURTHER NORTH. GOING BY ECMWF...FRONT ENDS UP DRAPED ACROSS THE
NORTHERN PORTION OF THE CWFA BY 12Z SATURDAY. CONSIDERING WHERE IT
HAS THE UPPER HIGH...THIS MAY BE EVEN TOO FAR SOUTH. AT THIS TIME...
WILL KEEP THURSDAY AND FRIDAY AS IS. WILL TONE DOWN TEMPS A LITTLE
ON SATURDAY AND THEN KEEP TEMPS ABOUT THE SAME OR A LITTLE WARMER
ON SUNDAY. WILL ALSO KEEP FORECAST DRY ON SATURDAY AND SUNDAY DUE TO
UNCERTAINTY AND SINCE IT IS 6 TO 7 DAYS AWAY.

.GLD...NONE.

BULLER