Hail and Damaging Wind in Kansas, August 19, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
311 PM CDT MON AUG 19 2002

DAYS 1-2...

OVERNIGHT AND EARLY MORNING CONVECTION HAS PRODUCED AN OUTFLOW
BOUNDARY EXTENDING FROM HUGOTON TO MEADE TO PRATT THIS AFTERNOON
BASED ON RADAR. DEWPOINTS ALONG AND JUST NORTH OF THE BOUNDARY WERE
NEAR 70 AS A RESULT OF A SHALLOWER MIXED LAYER AND CONVERGENCE.
THIS BDRY SHOULD BE ENOUGH TO FIRE A FEW PULSE TYPE STORMS LATE THIS
AFTERNOON. A LARGE COLD POOL WAS CENTERED OVER CENTRAL KS AND MAY
SERVE AS A SOURCE OF LIFT TONIGHT AS THE LOW LEVEL JET KICKS IN. SO
20-30 POPS SHOULD SUFFICE IN THE SOUTH FOR THE EVENING STUFF AND FOR
THE ELEVATED OVERNIGHT ACTIVITY. THE UPPER SUPPORT AND WINDS ALOFT
ARE NOT AS STRONG AS LAST NIGHT SO A LARGER MCS IS NOT LIKELY.
OTHER STORMS MAY DEVELOP ON UPSLOPE ALONG THE COLORADO FOOTHILLS
THIS EVENING, BUT THE UPPER LEVEL FLOW IS PROBABLY TOO WEAK TO PUSH
THIS INTO WESTERN KS. AREAS TO THE NW INCLUDING LBF-MCK SAY SEE SOME
OF THIS ACTIVITY LATER TONIGHT. SINCE ANY MCS TONIGHT WILL BE
FURTHER NORTH AND WEST, THE EFFECTIVE FRONT MAY MIX FURTHER NORTH
TUESDAY, LEAVING WESTERN KS IN HOT SOUTHERLY LOW LEVEL FLOW.
HOWEVER, GIVEN THE STRONG BAROCLINIC ZONE PRESENTLY, THERE STILL MAY
BE A BOUNDARY ACROSS THE AREA TUESDAY. A LARGE TROUGH WILL BE DEVELOPING
IN THE WEST BY MID-WEEK, ALLOWING FOR STRONG LEE TROUGHING AND EVEN
A SFC DRYLINE THAT MAY FOCUS AFTERNOON STORMS. WILL BOOST TEMPS UP A
FEW DEGREES FOR TUE-WED.

DAYS 3-7...
TODAYS DIAGNOSTICS SHOW GLOBAL AVERAGE ANGULAR MOMENTUM ANOMALIES
CONTINUING TO INCREASE. PERSISTENT AREAS OF TROPICAL CONVECTION
REMAIN NEAR 80E AND BETWEEN ABOUT 140E AND 160W WITH NO CLEAR
INDICATION OF AN MJO. THE HIGHER SEAS SURFACE TEMPERATURES
ASSOCIATED WITH THE ONGOING WEAK WARM ENSO EVENT ALSO CONTINUE.
UPPER LEVEL HEIGHT CONTOURS SUPPORT A LARGE AND FAIRLY NEBULOUS
POLAR VORTEX ENCOMPASSING MUCH OF THE ARCTIC AND INCLUDING GREENLAND
AND CANADA WHILE A LOWER LATITUDE WAVE 5 PATTERN PERSISTS ALOFT. THE
CROSS POLAR FLOW OBSERVED LAST WEEK APPEARS TO BE DIMINISHING IN
FAVOR OF GRADUALLY STRENGTHENING PACIFIC WESTERLIES AND THE
SUBTROPICAL RIDGE ALOFT NEAR THE DATE LINE CONTINUES TO SHOW SIGNS
OF BUILDING NORTHEAST INTO THE GULF OF ALASKA AND WESTERN CANADA.

THE SHORT TERM MODELS AGREE WITH THE DIAGNOSTICS IN DIGGING THE
CURRENT PACIFIC NORTHWEST SHORT WAVE DEEPER INTO THE WESTERN CONUS
AND CUTTING IT OFF AS THE MID PACIFIC SUBTROPICAL UPPER RIDGE WORKS
IN BEHIND. THIS CREATES A HIGHER AMPLITUDE PATTERN OVER WESTERN
NORTH AMERICA THAN WE HAVE SEEN IN A FEW WEEKS AND ALSO ALLOWS FOR
STRENGTHENING OF THE CROSS PACIFIC WESTERLIES FROM THE SIBERIAN
PLATEAU EASTWARD TO BEYOND THE DATE LINE. ALL MODELS ARE IN
REASONABLE AGREEMENT ON THE LARGE SCALE FEATURES MENTIONED ABOVE.
WITH TIME, THE MODELS ARE ALSO IN SOMEWHAT REASONABLE AGREEMENT ON
THE OVERALL LONG WAVE PATTERN THOUGH THERE ARE DIFFERENCES IN THE
MINORS MOVING THROUGH THIS PATTERN. IN ALL CASES, THEY FORECAST THE
EXPANSION OF THE WESTERLIES ACROSS THE PACIFIC WITH A SERIES OF
SHORT WAVE TROUGHS ALOFT IN THE FLOW. THE DIFFERENCES OCCUR IN
EXACTLY WHAT HAPPENS O EACH SUCCESSIVE SHORT WAVE TROUGH AS IT
REACHES WESTERN NORTH AMERICA.

FOR THE EARLY PERIODS OF THIS FORECAST, INDICATIONS ARE THAT THE
STRENGTHENING WEST SOUTHWEST TO EAST NORTHEAST FLOW ALOFT WILL
CONTINUE TO DEVELOP WITH MINOR SHOTS OF UPPER ENERGY ROTATING OUT OF
THE ROCKIES INTO THE HIGH PLAINS EACH AFTERNOON AND OVERNIGHT TO
INTERACT WITH THE REASONABLY WARM AND MOIST AIR IN PLACE OVER THE
REGION. FOR THIS REASON WILL INTRODUCE SOME SMALL CHANCE POPS FOR
WEDNESDAY AND THURSDAY EVENINGS.

BY THE COMING WEEKEND THERE IS GOOD AGREEMENT ON THE DEEPENING OF
THE EASTERN CONUS UPPER TROUGH WITH A NORTHWEST FLOW REGIME
DEVELOPING FOR AT LEAST A COUPLE OF DAYS OVER THE PLAINS. THIS
ARGUES FOR CONTINUED CHANCES FOR CONVECTION THROUGH THE WEEKEND AS
WELL AS A BIT COOLER THAN NORMAL TEMPERATURES DUE TO CLOUDS AND RAIN
COOLED AIR. MONDAY PROMISES ANOTHER UPPER WAVE MOVING THROUGH AND
WILL CONTINUE A CHANCE FOR CONVECTION AND COOLER TEMPERATURES.
WILL ALSO EXTEND THIS TREND INTO THE OUTLOOK PERIOD.

FINCH/JOHNSON

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

DDC   68  93  68  98 /  20  30  20  10
GCK   64  93  65  98 /  20  30  20  20
EHA   66  94  66  98 /  20  30  10  20
LBL   68  95  66  98 /  30  30  10  20
HYS   64  91  69  97 /  20  30  20  10
P28   73  97  71  97 /  30  30  20  10

.DDC...NONE.