Hail in Kansas, August 23, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
232 PM CDT FRI AUG 23 2002

...PROBLEM IS WHEN AND WHERE CONVECTION WILL FIRE AND ITS EFFECT
UPON THE BOUNDARY LAYER...

THE 12Z DIAGNOSTICS SHOW THE PERSISTENT CLOSED UPPER LOW OVER THE
PACIFIC NORTHWEST AND THE UPPER LEVEL POLAR BAROCLINIC ZONE FROM
SOUTHERN CALIFORNIA TO WESTERN KANSAS AND THENCE INTO NEW ENGLAND.
ALONG THE BAROCLINIC ZONE, CONVECTION WAS ONGOING FROM SOUTHEAST
COLORADO ACROSS THE FORECAST AREA INTO CENTRAL KANSAS. THE SURFACE
FRONT AT 18Z ROUGHLY BISECTS MY FORECAST AREA FROM WEST TO EAST.
LOOKING UPSTREAM ALONG THE POLAR BAROCLINIC ZONE, WATER VAPOR
IMAGERY AND MODEL INITIALIZATION VORTICITY FIELDS SHOW A SERIES OF
FAST MOVING, CLOSELY SPACED, LOW AMPLITUDE WAVES IN THE FLOW
SUPPORTING A CONTINUED CHANCE FOR CONVECTION ALONG THE FRONT.

MODEL INITIALIZATIONS CONTINUE TO BE REASONABLE WITH THE SYNOPTIC
SCALE FEATURES BUT DIFFER GREATLY IN THE RESULTS OF THEIR CONVECTIVE
PRECIPITATION FORECAST SCHEMES. NONE HAVE WORKED VERY WELL IN THE
PAST FEW DAYS AND WILL THUS AVOID THEIR SPECIFICS FOR A GENERAL
FORECAST BASED MORE UPON THE SYNOPTIC REGIME THAN ON MODEL OUTPUT.
IN THE LARGER SCALE, FEEL REASONABLY CONFIDENT THAT THE CLOSED UPPER
LOW OVER THE PACIFIC NORTHWEST STATES WILL SHEAR OUT AS ALL THE
MODELS PREDICT WHILE THE SUBTROPICAL RIDGE CURRENTLY OVER MEXICO AND
THE FAR SOUTHWEST STATES BUILDS NORTHWARD. THIS LEADS TO INCREASING
UPPER LEVEL HEIGHTS OVER THE FORECAST AREA BY SUNDAY BRINGING AN END
TO THE CHANCES FOR OVERNIGHT AND MORNING CONVECTION. UNTIL THEN,
HOWEVER, TONIGHT AND SATURDAY NIGHT WILL SEE A CHANCE FOR NOCTURNAL
THUNDERSTORMS DEVELOPING OVER THE HIGH TERRAIN TO THE WEST, BECOMING
ORGANIZED INTO SOME SORT OF MCS AND THEN SWEEPING OUT INTO THE
PLAINS AT NIGHT AND THROUGH THE MORNING HOURS.

AS TO TEMPERATURES, FWC GUIDANCE NUMBERS CONTINUE TO TREND SLOWLY
LOWER. THE PROXIMITY OF THE POLAR BAROCLINIC ZONE WITH CLOUDS AND AT
LEAST SOME RAIN COOLED OUTFLOW ARGUES FOR HIGHS A BIT LOWER THAN THE
GUIDANCE FOR SATURDAY. WILL CHOOSE TO AGREE WITH THE ETA AND MESOETA
AND PUSH THE POLAR BOUNDARY INTO TEXAS AND LEAVE THE FORECAST AREA IN
MUCH COOLER AIR. WILL THUS UNDERCUT FWC FOR HIGHS ON SUNDAY.

DAYS 3-7...
EXTENDED MODELS IN FAIR AGREEMENT TODAY CONCERNING THE DAY 3 THROUGH
7 PERIOD. WITH WARM FRONT RETURNING NORTH MONDAY, DECIDED TO
INTRODUCE CHC THUNDER POPS FOR MONDAY NIGHT. LATEST EC AND AVN HINT
AT ANOTHER COLD FROPA DURING THE MID-TO-LATE NEXT WEEK TIME FRAME.
WITH TIMING THE QUESTION AT THIS POINT, WILL TREND TEMPS DOWNWARD
ONLY FOR DAYS 6 AND 7 TO SLIGHTLY BELOW CLIMO NORMS.

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

DDC   66  87  66  88 /  30  20   0   0
GCK   65  89  65  90 /  30  20   0   0
EHA   65  95  67  92 /  30   0   0   0
LBL   65  93  68  91 /  30   0   0   0
HYS   67  85  67  86 /  50  40   0   0
P28   72  90  70  90 /  30  40   0   0

.DDC...NONE.

JOHNSON/MCCAMMON