Severe Thunderstorm Warning 357, NWS Dodge City, KS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
300 PM CDT FRI SEP 7 2001

...MAIN DIFFICULTY TODAY CENTERS ON UPPER FEATURE WHICH WILL ROTATE
THROUGH SOUTHWEST KANSAS THIS EVENING WITH A SECOND ON THE WAY FOR
SUNDAY...

ONGOING WEATHER PRECLUDES LENGTHY DISCUSSION. THE 12Z ANALYSIS
PACKAGE SHOWED THE DIGGING SOUTHERN BRANCH UPPER LOW OVER COLORADO
MOVING EAST INTO WESTERN KANSAS WHILE AN UPSTREAM NORTHERN BRANCH
COLD POOL WAS POISED TO ENTER MONTANA FROM THE NORTH. THESE FEATURES
WILL BE THE MAJOR PLAYERS IN THIS FORECAST. FIRST UPPER COLD POOL
ENTERING WESTERN KANSAS ALREADY PRODUCING CONVECTION AND STALLED
FRONT ACROSS MY FAR SOUTHEAST ZONES PROMISES TO DO SO SHORTLY.
ANY SEVERE THREAT ALONG THE FRONT IS LIKELY GOING TO BE EAST OF
THE AREA QUICKLY AND HAVE THUS OPTED TO LEAVE OUT OF THE SPC WATCH.
WILL STILL MENTION POSSIBLE SEVERE IN THE ZONE HOWEVER AND INCLUDE
MENTION FOR LOCALLY HEAVY RAIN THOUGH THIS WILL LIKELY NEED TO BE
UPDATED RAPIDLY BY LATE AFTERNOON.

LAST FEW DAYS MODELS HAVE DONE FAIRLY POORLY IN RESOLVING SMALLER
SCALE FEATURES AND WITH TIMING AND LOCATION OF PRECIPITATION. TODAY
WILL PLAY ONLY THEIR SYNOPTIC SCALE FORECASTS AND NOT BUY INTO THE
FINE SCALE. SCENARIO THEN WILL BE FOR UPPER LOW TO ROTATE THROUGH MY
ZONES BEFORE MIDNIGHT WITH DAMPENED SHORT WAVE RIDGE ALOFT AND
ASSOCIATED SUBSIDENCE IN PLACE THE REMAINDER OF THE NIGHT. BY
MORNING THE NORTHERN STREAM SHORT WAVE TROUGH MOVES BACK INTO
COLORADO AND WITH SUFFICIENT MID AND UPPER TROPOSPHERIC INSTABILITY
AND MOISTURE WILL LOOK FOR ANOTHER ROUND OF CONVECTION DEVELOPING
DURING THE DAY AND LASTING INTO SATURDAY NIGHT. THE UPPER TROUGH
AXIS SHOULD PASS DURING SUNDAY MORNING CONSIGNING THE AREA TO
SUBSIDENCE THROUGH THE REMAINDER OF SUNDAY.

BOUNDARY LAYER AIR WITH THESE TWO IMPULSES AND WITH THE REINFORCING
COLD FRONT ON SATURDAY LOOKS TO BE QUITE COOL WHEREAS THE NGM MOS
THINKS OTHERWISE. WILL STAY CLOSER TO THE COOLER AVN MOS FOR
TEMPERATURES AND WILL TRY TO TIME THE PRECIPITATION THROUGH THE AREA
WITH THE LARGER SCALE VORTICITY IMPULSES. WILL DO LAST MINUTE
PRECIPITATION ADJUSTMENTS FOR TONIGHT BASED UPON RADAR AND SATELLITE
MINUTES BEFORE ZONE TRANSMISSION SO FINAL NUMBERS MAY BE A LITTLE
DIFFERENT THAN THE PRELIMINARIES BELOW.

EXTENDED DISCUSSION...
IN THE DIAGNOSTICS TODAY GLOBAL ANGULAR MOMENTUM CONTINUES TO
DECLINE SHARPLY REFLECTING THE CURRENT HIGH WAVE NUMBER TRANSITION
WHILE THE OLR DATA SHOWS A CONTINUED MOIST PHASE OF THE MJO BUT WITH
ONLY VERY MINOR EASTERLY PROGRESSION ALONG THE ITCZ. THE CURRENT
PATTERN SUGGESTS A GRADUAL TRANSITION TO DEEP CENTRAL PACIFIC UPPER
TROUGH WITH A MEAN UPPER RIDGE OVER THE EASTERN PACIFIC AND WESTERN
NORTH AMERICA AS THE FULL LATITUDE TROUGH OVER THE CENTRAL CONUS
LIFTS OUT ON MONDAY. THE GOING EXTENDED FORECAST HAS THIS WELL IN
HAND THROUGH MID WEEK. ALSO AGREE WITH THE CHANCE FOR CONVECTION
THURSDAY AS THE POLAR BAROCLINIC ZONE SINKS SOUTH AGAIN BRIEFLY WITH
A SOUTHERN CONUS UPPER RIDGE ESTABLISHING ITSELF ACROSS THE REGION
INTO NEXT WEEKEND LEADING TO WARMER AND DRIER CONDITIONS.

PRELIMINARY GUIDANCE FOR COORDINATION ONLY. OFFICIAL FORECASTS ARE
CONTAINED WITHIN THE DODGE CITY ZONE FORECAST.

DDC 054/065 050/070 047 32+
GCK 051/065 050/071 045 32+
EHA 052/066 050/073 045 12+
LBL 054/066 052/072 048 12+
HYS 056/066 052/070 048 44+
P28 060/070 057/070 052 4-+

.DDC...NONE.

JOHNSON/BURGERT