Tornadoes and Hail in Kansas, April 21, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
302 PM CDT SAT APR 21 2001

MAIN FORECAST CHALLENGE TODAY WILL BE CHANCES FOR CONVECTION TONIGHT
AND SUNDAY.

25H ANALYSIS AT 12Z INDICATED ONE 80KT JET ALONG THE WRN OK/ERN TX
PANHANDLE BORDER. ANOTHER JET OF 110KS WAS LOCATED IN SRN AZ. DDC
SOUNDING SHOWING LOW LEVEL MOISTURE BEHIND THIS DRY LINE IN OUR
EASTERN CWA WAS VERY DRY, WHILE GOOD CONV AND MADV PRESENT ALONG DRY
LINE. DELTA T'S GREATER THAN 18 AT 12Z AND WITH SOME 7H WAA AND CAA
AT 5H BETTER INSTAB WILL BE IN PLACE THIS EVENING PRIOR TO THE MAJOR
WAVE EARLY SUNDAY. AS OF 18Z GRANADA PROFILERS AND KDDC VAD WINDS
ALREADY SHOWING A SOUTHEAST FLOW RETURNING WITH DWPTS RISING INTO
THE 60S AT P28. MSAS SHOWING LI INDEXES ALREADY NEG ALONG WARM FRONT
WHICH EXTENDED FROM ROUGHLY EAST CENTRAL COLORADO INTO NW OKLAHOMA.
VIS ALSO SHOWING SOME CU ALSO DEVELOPING HERE AS WELL. BETTER CU
FIELD NOTED NEAR P28 WHERE MCON FIELD AND TADV IS BEST.
EXTRAPOLATION ON THE S/W TROF IN SRN AZ PLACES THIS WAVE IN SE CO BY
23Z. AS A RESULT WILL GO WILL LIKELY POPS TONIGHT ALONG AND NORTH OF
THE WARM FRONT WHILE JUST EAST OF THE DRYLINE CARRY CAT POPS.

GIVEN THE WIND PROFILE VIA PROFILERS FROM HAVILAND AND GRANADA ALONG
WITH KDDC VADS, BOUNDARIES DISSECTING THE CWA AND INSTAB ALOFT WILL
MENTION THE THREAT THAT SOME STORMS MAY BE SEVERE FOR ALL BUT THE
SOUTHWEST NEAR EHA WHERE MOISTURE WILL BE MOST LIMITED. HOWEVER EVEN
HERE SOME WINDS WILL BE POSSIBLE FROM THE INITIAL ELEVATED
CONVECTION.

THE MORE SIGNIFICANT SYSTEM STILL APPEARING FAIRLY DYNAMIC WITH
CONVECTION VISIBLE AHEAD OF THIS WAVE. MODELS CONTINUE TO SHOW THIS
WAVE ROTATING INTO THE CENTRAL PLAIN EARLY ON SUNDAY. 5H AND 7H HT
FALLS REMAIN IN THE BASE OF NEXT UPPER LOW CURRENTLY LOCATED IN
SOUTHEAST CALIFORNIA AT 12Z SAT WHICH LEAD ME TO FOLLOW THE ETA AND
AVN SLIGHTLY SLOWER SOLUTION. EVEN GOING WITH THIS SOLUTION THERE
WILL BE GOOD PVA PRESENT ACROSS ENTIRE AREA BY 12Z SUN WHICH
SUPPORTS HIGH CHANCE TO LIKELY CONTINUING. DEEPENING SFC PRESSURES
ALONG SE COLORADO SHOULD PLACE THE SFC FRONT IN THE MIDDLE OF THE
CWA BY MORNING. MOISTURE AND LIFT COMING TOGETHER BEST IN THE NORTH
AND EAST SO WILL PLACE THE HIGHEST POPS HERE. DEEPENING PRESSURE
WILL ALSO KEEP THE WINDS UP OVERNIGHT SHOULD SEE WINDY CONDITIONS
ACROSS THE AREA ON SUNDAY. UPPER LOW MOVES FROM NEW MEXICO OVER
WESTERN KANSAS DURING THE AFTERNOON WITH A SLOT OF DRYER AIR
SUGGESTING PARTLY/MOSTLY CLEAR CONDITIONS BY NOON. HOWEVER VERY
UNSTABLE AIR IN PLACE WITH COLD POOL ALOFT AND AS SOME MOISTURE
WRAPS AROUND THE DEEPENING 85H LOW SOME CONVECTION WILL STILL BE
POSSIBLE IN THE LATE AFTERNOON AND EVENING.

CAA BEGINS TO TRULY MAKE ITS PRESENT FELT ON MONDAY NIGHT AS 85H
TEMPS FALLS FROM 6-8C OVER A 6H TIME FRAME. PLACEMENT OF THIS SYSTEM
IS EVERYTHING FOR LOCATION OF THE WRAP AROUND MOISTURE AND LIFT. AT
THIS TIME WILL KEEP TO LOW POPS GOING SUNDAY NIGHT IN THE SOUTH
GIVEN THE INSTAB ALOFT AND HIGHER CHC POPS IN THE NORTH GIVEN
CURRENT ETA/AVN TRACK. WILL HOLD OFF AT THIS MOMENT MENTIONING ANY
TYPE OF PCPN CHANGE OVER GIVEN THE COLD AIR INVADING THE NORTHWEST
BUT THIS MAY BE A CLOSE CALL IN OUR NORTHWEST.

COOL DOME OF HIGH PRESSURE MOVES INTO WESTERN KANSAS ON MONDAY AS
SUBSIDENCE DEVELOPS ALOFT. ETA WAS THE SLOWEST TO ERODE THE COLD
AIR AND GIVEN 85H TEMP PROGS AT 00Z TUE LOWER 60S FOR HIGHS ON
MONDAY LOOK REASONABLE FOR DDC AND MID 60S FURTHER WEST.

EXTENDED DISCUSSION...

THE 21/00Z MRF RUN IS VERY CLOSE TO 20/12Z ECMWF AND THE 21/12Z RUN
OF THE UKMET WITH RESPECT TO THE POSITION OF THE 500 MB TROUGH OVER
THE GREAT LAKES STATES AT 120 HR/25/12Z.  AFTER THAT PERIOD, THE MRF
IS MORE AGGRESSIVE WITH THIS TROUGH THAN THE ECMWF/UKMET AS IT
ENCOUNTERS THE MID-ATLANTIC SEABOARD.  FOR THE MOST PART, THINK THE
MRF IS ON TRACK, BUT THEN STARTS DIVING CANADIAN COLD AIR ALOFT
SOUTHWARD TOO FAST.  WILL LEAN TOWARD THE FMR GUIDANCE UP THROUGH
WEDNESDAY PERIOD, BUT NOT WARM HIGH TEMPS UP QUITE AS QUICKLY AS MRF
FOR THURSDAY THROUGH SATURDAY PERIOD.  AFTER 1ST 48 HOURS PRECIP
EVENT FINISHES, UPPER RIDGE WILL TAKE HOLD OF SOUTHWESTERN KANSAS
(AND SOUTHWESTWARD).  THINK A SURFACE LEE TROUGH WILL FLIRT WITH
WEST KANSAS BORDER EACH AFTERNOON FROM WEDNESDAY ONWARD, BUT DO NO
SEE ENOUGH UPPER SUPPORT TO INTRODUCE CONVECTION AT THIS TIME.
SLIGHT CHANCE WORDING WILL LIKELY BE REQUIRED SOMETIME BETWEEN WED
AND SAT, BUT WILL LET LATER SHIFTS REFINE WHERE.

NO CHANGES PLANNED FOR NEW 8-10 DAY OUTLOOK, STAYING WITH ABOVE
NORMAL TEMPS (40S-ARND 70 DEG) AND NEAR NORMAL PRECIP (20-30% POP).

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

DDC 055/067 035/061 035 753
GCK 054/063 032/062 032 754
EHA 053/065 032/06S4 032 422
LBL 057/066 033/063 033 752
HYS 055/060 035/056 032 774
P28 060/070 043/063 040 862

.DDC...NONE.

RB/BURKE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DODGE CITY, KS
215 PM CDT SAT APR 21 2001

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....
b
0810 PM    13 WNW LARNED               KS   .75 INCH HAIL
04/20/01   PAWNEE

JF