Hail and Damaging Wind in Kansas, July 26, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
250 PM CDT THU JUL 26 2001

...FORECAST CHALLENGE TODAY CONTINUES TO BE TEMPERATURES AND
TIMING/LOCATION OF CONVECTION...

THE 12Z ANALYSIS PACKAGE SHOWED THE MAIN POLAR WAVE TRAIN STILL WEST
TO EAST ACROSS THE NORTHERN CONUS WITH A CLOSED UPPER LOW NEAR LAS.
A WARM UPPER RIDGE REMAINS IN PLACE OVER THE SOUTHERN PLAINS. IN THE
LOWER LEVELS THE CONVECTIVE COMPLEX WHICH CROSSED WESTERN KANSAS
OVERNIGHT PRODUCED RAIN COOLED OUTFLOW WHICH ASSISTED IN DRIVING THE
WEST TO EAST SURFACE FRONT A LITTLE FARTHER SOUTH INTO OKLAHOMA AND
THE TEXAS PANHANDLE BY THIS MORNING. NORTH OF THE FRONT EASTERLY
UPSLOPE CONTINUES ACROSS KANSAS INTO EASTERN COLORADO. MODIFYING THE
DDC 12Z SOUNDING FOR EXPECTED AFTERNOON TEMPERATURES PRODUCES 4200
J/KG OF B+ AGAIN TODAY.

A MAJOR FACTOR FOR THIS FORECAST IS THE CLOSED LOW OVER THE DESERT
SOUTHWEST WHICH IS FORECAST TO LIFT OUT INTO THE PLAINS. THE ETA
MODEL INITIALIZED BEST WITH THIS LOW AND WILL GENERALLY BE FOLLOWED
FOR SYNOPTIC SCALE FEATURES. CONVECTIVE FEEDBACK INTO THE MODELS
CONTINUES TO BE A PROBLEM WITH TIME.

YESTERDAYS MODEL RUNS HAD FORECAST THE SOUTHWEST CONUS CLOSED LOW
OVER COLORADO BY LATE THIS AFTERNOON. TODAYS RUNS ARE SLOWER AND
FARTHER NORTH. AS THIS WAVE LIFTS INTO COLORADO TONIGHT LEE
CYCLOGENESIS SHOULD STRENGTHEN THE SOUTHERLY BOUNDARY LAYER FLOW.
THUS THE FRONT WILL ATTEMPT TO MOVE NORTHWARD. HOWEVER, THE FRONT
WILL ALSO PROVIDE FOCUS FOR AFTERNOON/EVENING CONVECTION ONCE AGAIN
AS INSOLATION REALIZES THE POTENTIAL INSTABILITY. RAIN COOLED AIR
FROM THE CONVECTION WILL LIKELY HOLD THE FRONT FARTHER SOUTH THAN
EVEN THE MORE CONSERVATIVE ETA AND WILL MAKE ADJUSTMENTS FOR THAT.
THE END RESULT WILL BE TO HAVE THE FRONT, THE EASTERLY UPSLOPE FLOW
NORTH OF IT, AND THE UPPER LEVEL SHORT WAVE TROUGH PRODUCE ANOTHER
CONVECTIVE COMPLEX FOR TONIGHT AND WILL THUS MAINTAIN THE LIKELY
POPS IN THE GOING FORECAST. FRIDAY NIGHT SHOULD SEE A RERUN AS THE
UPPER WAVE MOVES OUT INTO THE PLAINS. WILL ALSO KEEP SOME SMALL
CHANCE POPS EACH DAY FOR ANY CONVECTION THAT MAY LINGER IN THE
MORNING OR COOK OFF IN THE UNSTABLE BOUNDARY LAYER ALONG THE FRONT
EACH AFTERNOON.

TEMPERATURES WILL BE A REAL GRAB BAG AS THEY WILL DEPEND UPON THE
AMOUNT OF RAIN COOLING OF THE BOUNDARY LAYER AND THE AMOUNT OF CLOUD
COVER EACH DAY. THE GOING FORECAST IS AGAIN ON TRACK HERE AND WILL
CHANGE LITTLE.

EXTENDED DISCUSSION...
MODELS SOLUTIONS OVER THE CONUS APPEAR TO BE CONGEALING FAIRLY WELL
WITH DAY 5 SKILL SCORES SHOWING RELATIVELY HIGH SKILL OVER PAST FEW
DAYS. ALL SOLUTIONS INDICATE UPPER RIDGE WILL TAKE CONTROL OF THE
CENTRAL TO EASTERN CONUS CENTERING ITSELF OVER THE PLAINS. WITH
GLOBAL ANGULAR MOMENTUM RATHER LOW, THE HINT OF THE BEGINNING OF THE
MOIST PHASE OF THE MJO, AND CONSIDERING ITS PERFORMANCE OF LATE,
WOULD FAVOR THE ECMWF SOLUTION WITH THE GULF OF ALASKA RIDGE
REMAINING STRONG IN A MORE AMPLIFIED PATTERN. THIS MAY ALSO ALLOW
SOME TROPICAL MOISTURE TO IMPINGE ON THE HIGH PLAINS ALONG WITH
SOUTHERLY LOW LEVEL FLOW PUSHING LOW LEVEL MOISTURE UP AS WELL
TOWARD MID WEEK. WILL CONTINUE TO KEEP THE FORECAST DRY THOUGH WITH
THE UPPER HIGH LIKELY TO BE NEARLY OVERHEAD AND AM AFRAID ALL THE
MOISTURE WILL DO IS MAKE HEAT INDICES RISE. WILL KEEP SMALL POPS
GOING FOR SATURDAY NIGHT WITH SOME LOW LEVEL BAROCLINICITY AND THE
LOW LEVEL JET INCREASING AHEAD OF THE DEVELOPING WESTERN TROUGH.

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

DDC 070/093 070/093 070 626
GCK 068/093 068/093 068 626
EHA 069/096 069/096 069 626
LBL 070/095 070/095 070 626
HYS 070/088 070/088 067 646
P28 073/095 073/094 072 646

.DDC...NONE.

JOHNSON/POAGE