Severe Thunderstorm Warning 409, NWS Dodge City, KS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
257 PM CDT TUE OCT 9 2001

...MAIN CONCERN WILL BE CHANCES FOR SEVERE CONVECTION IN THE FIRST
12 HOURS OF THIS CYCLE AND TEMPERATURES IN THE LATER PERIODS...

THE 12Z DIAGNOSTICS INDICATE A COMPLEX SITUATION ACROSS THE CONUS
WITH A STRONG UPPER TROUGH DIGGING INTO THE WESTERN REGION WHILE A
SOUTHERN BRANCH UPPER SHORT WAVE EXITS ACROSS KANSAS EARLY THIS
AFTERNOON. IN THE LOW LEVELS A SHARP DRY LINE WAS ALREADY IN PLACE
BY NOON ACROSS WESTERN KANSAS WITH THE OLD POLAR WARM FRONT ACROSS
CENTRAL KANSAS. THE LATTER WAS IDENTIFIABLE AS A 900-850MB FRONTAL
INVERSION ON THE TOP SOUNDING AT 12Z BUT WAS EAST OF DDC AT THAT
TIME. THIS FEATURE SEEMS TO HAVE BEEN LOST OVERNIGHT IN THE NCEP
FRONTAL ANALYSIS THOUGH IT HELPS EXPLAIN THE BAND OF ELEVATED
CONVECTION NOW WORKING ACROSS NORTHEAST KANSAS. A SURFACE COLD FRONT
ASSOCIATED WITH THE NORTHERN BRANCH SYSTEM DIGGING INTO THE PLAINS
WAS ALREADY WORKING SOUTHEAST ACROSS COLORADO AS THE WARM LEE TROUGH
MOVES OUT AHEAD OF IT.

NOT A LOT OF TIME SPENT ON MODEL VALIDATION TODAY SINCE THE MAIN
PLAYERS IN THIS EVOLVING TABLEAU ARE ALL WELL INTO THE DATA RICH
CONUS REGION PROVIDING VERY SIMILAR INITIALIZATIONS AND FORECASTS
AMONG THE MODELS. THE FIRST WAVE MOVING ACROSS KANSAS THIS AFTERNOON
HAS ALREADY INITIATED CONVECTION THROUGH WESTERN AND CENTRAL
OKLAHOMA WHILE THE NORTHERN BRANCH WAVE SHOULD MOVE ACROSS COLORADO
THIS AFTERNOON AND KANSAS TONIGHT. THE EARLY CONVECTION MAY TAG MY
SOUTHEAST ZONES THIS AFTERNOON.

BY LATER TODAY THE MAINLY CLEAR SKIES ACROSS MOST OF MY ZONES SHOULD
YIELD PLENTY OF HEATING IN ADVANCE OF THE APPROACHING DRY LINE AND
SURFACE FRONT. THE 18Z DDC RAOB INDICATES MAX SBCAPE ALONG THE DRY
LINE THIS AFTERNOON CLOSE TO 3500 J/KG WITH REASONABLE DEEP LAYER
SHEAR THIS EVENING AS THE NORTHERN BRANCH SYSTEM APPROACHES. AS THE
FRONT DIGS SOUTH TONIGHT AND INTERSECTS THE RETREATING DRY LINE OVER
MY EASTERN ZONES THERE SHOULD BE AT LEAST SOME ISOLATED SEVERE
STORMS AND POSSIBLY A STORM OR TWO EARLIER IN CONVERGENCE ON THE DRY
LINE. GIVEN LOW LCLS IN THIS AREA ALONG WITH THE HIGH ENERGY
HELICITY INDEX, AN ISOLATED TORNADIC SUPERCELL IS NOT OUT OF THE
QUESTION. COORDINATION WITH SPC SUPPORTS THIS SCENARIO. HIGHEST
OVERNIGHT POPS WILL BE RESERVED FOR MY EAST AND SOUTHEAST ZONES. THE
MAIN CONCERN AT THE MOMENT IS CONVECTIVE INITIATION.

THE NORTHERN BRANCH COLD FRONT SHOULD CLEAR ALL OF MY ZONES
OVERNIGHT. FORECAST H8 TEMPERATURES FOR TOMORROW SUPPORT
CONSIDERABLE COLD AIR ADVECTION WITH MORNING LOW TEMPERATURES AND
AFTERNOON HIGHS A BIT COOLER THAN THE FWC. BOUNDARY LAYER
CIRCULATIONS IN THE COLD AIR SHOULD ALSO PROVIDE FOR A FAIR AMOUNT
OF COLD AIR STRATOCUMULUS WHICH WILL ALSO CUT DOWN THE HEATING. PER
ALL MODELS THE AXIS OF THE UPPER LEVEL TROUGH WILL NOT PASS UNTIL
WEDNESDAY NIGHT SO THE RISK OF SOME ELEVATED SHOWERS WILL REMAIN
UNTIL THEN AND WILL KEEP SOME VERY SMALL POPS FOR THIS EVENTUALITY
MAINLY IN MY SOUTHEAST ZONES. AS SUBSIDENCE INCREASES OVER THE
REGION LATE WEDNESDAY NIGHT WILL LOOK FOR THE COOLEST TEMPERATURES
BY THURSDAY MORNING WITH MAY AREAS INTO THE 30S. AS THE SURFACE
RIDGE WORKS EASTWARD ON THURSDAY WEAK SOUTHERLY FLOW ON THE WEST
SIDE OF THE SURFACE HIGH WILL DEVELOP BUT NOT NEARLY AS MUCH WARMING
AS THE FWC EXPECTS AND WILL THUS KEEP HIGH TEMPERATURES QUITE A BIT
LOWER THAN THE MOS.

EXTENDED DISCUSSION...
THE CURRENT EXTENDED FCST LOOKS ON TARGET AND NO CHANGES ARE
ANTICIPATED EXCEPT TO ADD DAY 7. THE 12Z SUITE OF MODELS GENERALLY
AGREE THAT THE NEXT WAVE WILL BE MOVING THROUGH THE ROCKIES BY
THURSDAY NIGHT. AHEAD OF THE WAVE THE MOISTURE WILL ATTEMPT TO
RETURN THE SCENIC ROUTE THROUGH OLD MEXICO AND INTO EASTERN NM AND
THE TX PANHANDLE. RIGHT NOW IT APPEARS THAT MOISTURE MAY NOT MAKE
IT BACK UNTIL EARLY FRIDAY. THUS WE WILL KEEP THURSDAY NIGHT DRY.
WITH STRONG RETURN OF MOISTURE AND H5 COLD POOL MOVING INTO WESTERN
KS FRIDAY, THUNDERSTORM CHANCES LOOK GOOD. AN EVEN STRONGER WAVE IS
PROGGED TO APPROACH THE HIGH PLAINS SATURDAY. WE COULD HAVE PROBLEMS
GETTING MOISTURE BACK FOR THIS SYSTEM BUT GIVEN THE STRONG DYNAMICS
WE WILL LEAVE CHANCE OF SHOWERS/STORMS IN THE FCST. A STRONG COLD
FRONT SHOULD MOVE THROUGH BY SATURDAY NIGHT.

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

DDC 050/063 038/068 040 1-0
GCK 048/064 036/069 039 -10
EHA 049/064 038/072 040 -10
LBL 051/063 039/070 041 -10
HYS 048/060 037/065 039 2-0
P28 057/069 043/069 045 4-0

.DDC...NONE.

JOHNSON/FINCH