Severe Thunderstorm Warning 169, NWS Dodge City, KS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
312 PM CDT WED JUL 12 2000

...MAIN QUESTIONS FOR THIS CYCLE WILL BE AMOUNT, LOCATION, AND
TIMING OF CONVECTION...

12Z HAND ANALYSIS SHOWS THAT THE MODELS OVERALL PATTERN FORECAST OF
THE PAST FEW DAYS HAS COME TO FRUITION. A HUGE WARM CORE HIGH
DOMINATES THE SOUTHERN PLAINS AND SOUTHERN ROCKIES WITH NUMEROUS
EMBEDDED POOLS OF WARM AND COOL AIR WANDERING AROUND IN THE CENTER
OF THE HIGH.  MORNING SOUNDING ANALYSIS INDICATES AFTERNOON SBCAPE
THIS AFTERNOON AROUND 3500 J/KG ACROSS KANSAS SO MORE CONVECTION IS
VIRTUALLY ASSURED. SURFACE POTENTIAL TEMPERATURE AND PRESSURE FIELDS
AT 12Z IDENTIFIED A WEAK COLD FRONT FROM TOP TO JUST SOUTH OF DDC
AND THENCE NORTHWEST INTO EAST CENTRAL COLORADO AND AN OUTFLOW
BOUNDARY ACROSS THE TEXAS AND OKLAHOMA PANHANDLES FROM NOCTURNAL
CONVECTION IN EASTERN NEW MEXICO AND THE PANHANDLES. THE
INTERSECTION OF THESE TWO FEATURES HAS APPARENTLY FORCED MORNING
CONVECTION ALONG AND SOUTH OF THE BOUNDARY FROM NORTHWEST OKLAHOMA
TO SOUTHWEST KANSAS AND INTO EAST CENTRAL COLORADO.

MODEL FORECASTS INDICATE THAT THIS SYNOPTIC SCALE REGIME WILL
CONTINUE THROUGHOUT THE FORECAST PERIOD. THE FORECAST PROBLEM, THEN,
CENTERS ON THERMODYNAMICS AND RESULTING MESOSCALE FEATURES. IT IS
SIMILAR TO WATCHING A PAN OF WARM WATER OVER AN UNEVEN HEAT SOURCE
AND TRYING TO DETERMINE WHERE AND WHEN THE NEXT BUBBLE WILL RISE.
ATTEMPTS TO FORECAST CONVECTIVELY FORCED MESOSCALE FEATURES FOR MORE
THAN A FEW HOURS WILL BE USELESS. FOR THE NEAR TERM WILL PLAY THE
NEARLY STATIONARY SURFACE FRONT TO CONTINUE TO FURNISH CONVERGENCE
FOR CONVECTION THROUGH MY SOUTHERN AND SOUTHWESTERN ZONES,
ESPECIALLY AS AFTERNOON HEATING ADDS TO DESTABILIZATION OF THE
BOUNDARY LAYER. WILL GO ABOVE GUIDANCE POPS IN THAT AREA. IN LATER
PERIODS, WITH THE UNSTABLE TROPICAL AIRMASS STILL IN PLACE, ALL WILL
HINGE UPON THE LOCATION AND STRENGTH OF ANY LEFT OVER BOUNDARIES.
NONE OF THE MODELS ARE VERY DEFINITE ABOUT THIS, NOR WOULD I EXPECT
THEM TO BE. WITH AT LEAST SOME SURFACE LEE/WARM TROFING ALONG THE
LEE SLOPES, WILL EXPECT BOUNDARY LAYER SOUTHEAST FLOW TO HOLD THE
REMAINS OF THE OLD FRONT SOMEWHERE IN EAST COLORADO AND WEST KANSAS
AND PLAY CONTINUED HIGHER POPS FOR MY WESTERN ZONES ALL PERIODS WITH
THE BEST CHANCES WHEN INSTABLILITY IS MAXIMIZED IN THE LATE
AFTERNOON OR EVENING.

MOSOONAL MOISTURE REMAINS EVIDENT ACROSS NEW MEXICO IN THE MID
TROPOSPHERE SO AFTERNOON CONVECTION IN THE MOUNTAINS SHOULD CONTINUE
TO DEVELOP CONVECTIVELY INDUCED VORTICITY IN THAT AREA AND ROTATE
IT ACROSS THE HIGH PLAINS. WHEN THESE RIPPLES ARRIVE OVER THE REGION
MORE CONVECTION IS LIKELY. TIMING FOR THIS IS NEAR IMPOSSIBLE BUT
AGAIN THE BEST CHANCE FOR CONVECTION WITH THIS FEATURE SHOULD BE
DURING THE MOST UNSTABLE PARTS OF THE DAY. MORE NOCTURNAL CONVECTION
CANNOT BE RULED OUT EITHER SIMILAR TO THIS MORNING SO WILL GENERALLY
LEAVE POPS OF SOME SORT IN ALL PERIODS IN THE WEST AND SOUTHWEST.

SOME CONCERN EXISTS FOR POTENTIAL HEAVY RAINFALL WITH SOME OF THESE
TROPICAL STORM CLUSTERS AS THE MORNING SOUNDING SHOWED PRECIPITABLE
WATER AMOUNTS OF 1.67 INCHES WHICH IS OVER 150 PERCENT OF NORMAL.
SINCE IT IS IMPOSSIBLE TO DETERMINE WHERE THE HEAVIEST RAINFALL WILL
BE ACROSS THE CWA, NO FLASH FLOOD WATCH WILL BE ISSUED. THIS PROBLEM
IS BEST ATTACKED IN THE SHORT TERM AND WITH NOWCASTS AND THE
HAZARDOUS WEATHER OUTLOOK.

EXTENDED DISCUSSION...
EXTENDED MODELS AND ENSEMBLES ALL SUGGESTING UPPER RIDGE AXIS SLOWLY
SHIFTS TO THE EAST AND WEAKENS OVER THE WEEKEND PERIOD. HARD TO
DISCOUNT CHC OF EVENING CONVECTION ANY ONE DAY OVER THE WEEKEND
PERIOD GIVEN LITTLE SIG CHANGE IN THE GENERAL PATTERN. STILL APPEARS
MONDAY WILL HAVE A COLD FRONT MOVE INTO CWA WHICH WILL KEEP A SLT
CHC GOING.

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

DDC 069/094 070/096 068 211
GCK 068/094 068/097 067 211
EHA 068/089 068/097 068 533
LBL 070/090 070/098 070 533
HYS 072/096 072/098 072 ---
P28 072/098 072/098 071 1--

.DDC...NONE.

JOHNSON/RB

KSZ030-031-043>046-061>066-074>081-084>090-130505-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DODGE CITY KS
348 PM CDT WED JUL 12 2000

...A FEW SPOTTERS COULD BE REQUIRED THIS EVENING AND OVERNIGHT
ALONG AND SOUTHWEST OF A LAKIN TO SUBLETTE AND MEADE LINE...

A CONVERGENCE BOUNDARY HAS FINALLY SETTLED IN FROM NORTHEAST
COLORADO SOUTHWEST ACROSS FAR SOUTHWEST KANSAS WITH THUNDERSTORMS
ALREADY FIRING UP IN COLORADO. A FEW OF THESE STORMS MAY WORK THEIR
WAY SOUTHEAST ALONG THE BOUNDARY INTO FAR SOUTHWEST KANSAS.

MEANWHILE, A WEAK UPPER LEVEL DISTURBANCE OVER NORTHEAST NEW MEXICO
IS EXPECTED TO FIRE ADDITIONAL THUNDERSTORMS ACROSS THE TEXAS AND
OKLAHOMA PANHANDLE AREA. A FEW OF THESE STORMS MAY ALSO MOVE
NORTHEAST INTO FAR SOUTHWEST KANSAS FROM LIBERAL TO HUGOTON AND
ELKHART.

VERY WEAK WIND FLOW IN THE MID AND UPPER LEVELS OF THE ATMOSPHERE
WILL MEAN THAT THESE STORMS SHOULD BE FAIRLY SHORT LIVED AND WILL
MOVE LITTLE AFTER DEVELOPING. A FAIRLY DRY LAYER OF AIR WILL BE JUST
BELOW THE BASES OF THESE STORMS AND MAY LEAD TO SOME VERY STRONG
WIND FLOWING OUT OF THE STORMS AS THEY COLLAPSE. THIS WILL BE THE
MAIN DANGER FROM THESE STORMS IN THE SHORT TERM.

THE AIRMASS THAT WILL FEED THE STORMS IS EXCEEDINGLY MOIST SO THE
STORMS ARE LIKELY TO PRODUCE TORRENTIAL RAINS AND POSSIBLY SOME
LOCAL FLASH FLOODING. OFFICIALS SHOULD REMAIN ALERT TO THIS
POSSIBILITY AS THE EVENING PROGRESSES.

FOR ADDITIONAL WEATHER INFORMATION, PLEASE VISIT OUR WEB SITE AT:
http://www.dodgecity.net/nws/

JOHNSON