Severe Thunderstorm Warning 80, NWS Goodland, KS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
206 PM MDT THU MAY 29 2003

FORECAST PROBLEMS WILL BE CHANCE FOR THUNDERSTORMS TONIGHT...FRIDAY
NIGHT...AND AGAIN ON SUNDAY.

TONIGHT...LATEST RUC/ETA/ETA KF ALL INITIATE CONVECTION OVER THE
FORECAST AREA LATE THIS AFTERNOON AND INTO THE EVENING HOURS. RUC
LOOKS TO BE DOING BEST AND WILL GO WITH IT FOR TONIGHT. TWO AREAS OF
CONVECTIVE INITIATION ARE OF CONCERN. FIRST ALONG THE SURFACE
TROUGH WHERE LINE OF TCU ARE CURRENTLY EVIDENT ON VISIBLE SATELLITE
IMAGERY...FROM CHEYENNE COUNTY COLORADO NORTHEAST TOWARDS MCCOOK.
SECOND AREA OF CONCERN IS ALONG THE CHEYENNE RIDGE IN NORTHERN
COLORADO/SOUTHERN WYOMING. TCU ALSO ON VISIBLE IN THAT AREA AND RUC
EXTENDS LIFT/CONVECTION SOUTHEASTWARD. UPSHOT IS THAT CONVECTION
WILL BE POSSIBLE ALMOST ANYWHERE AND WILL BLANKET THE FORECAST AREA
WITH ISOLATED POPS. SOUNDING ANALYSIS SUGGESTS EXTREMELY HIGH BASED
THUNDERSTORMS...AROUND 600 MB...SO DRY MICROBURST THREAT A REAL
POSSIBILITY. EXPECT ACTIVITY TO END BY 06Z AS SUBSIDENCE AND CIN
OVERSPREAD THE AREA.

FRIDAY...LOSS OF DOWNSLOPE WINDS WILL PREVENT MAXIMUM TEMPERATURES
FROM REACHING THE EXTREMES SEEN TODAY. WILL GO SLIGHTLY UNDER
WARMEST ETA MOS GUIDANCE. SHORT TERM MODELS ARE IN REASONABLE
AGREEMENT FOR PRECIPITATION EVENT FRIDAY NIGHT...PARTICULARLY IN
AREAL COVERAGE. GFS CONTINUES MOST AGGRESSIVE HOWEVER WITH QPF.
LITTLE CHANGE TO GOING FORECAST EXCEPT TO INCREASE POPS ALL ZONES
CORRESPONDING TO INCREASED CONFIDENCE.

SATURDAY/SUNDAY...SURFACE HIGH SLIDES EAST SATURDAY RESULTING IN
TIGHTENING PRESSURE GRADIENT IN RETURN FLOW. EXPECT BREEZY WINDS AND
COOLER TEMPERATURES IN UPSLOPE REGIME. WEAK SHORTWAVE COMES THROUGH
SUNDAY NIGHT. HOWEVER SHORT TERM MODELS HAVE TONED DOWN QPF AND MOISTURE
AND INSTABILITY PARAMETERS ARE NOT THAT IMPRESSIVE. WILL TRIM
OVERNIGHT PRECIPITATION CHANCES. FOR SUNDAY MOISTURE AND INSTABILITY
AXIS WILL BE MAXIMIZED OVER EASTERN COLORADO. MORE IMPRESSIVE
SHORTWAVE NOW EVIDENT AT 500 MB AND GIVEN MOISTURE AND DAYTIME
HEATING CONTRIBUTIONS WILL TIER CHANCE TO SLIGHT CHANCE WEST TO
EAST.

EXTENDED (MONDAY THROUGH THURSDAY)...GFS ENSEMBLE MEMBERS AND ECMWF
ARE IN BETTER AGREEMENT ON LATEST RUNS FOR THE EXTENDED. ON MONDAY
WEST COAST RIDGE WILL BE FLATTENED BY SHORTWAVE ENERGY MOVING ALONG
THE NORTHERN ROCKIES NEAR THE CANADIAN BORDER. SURFACE REFLECTION
HAS LOW SPINNING UP OVER THE NORTHERN PLAINS WITH TRAILING COLD
FRONT MOVING THROUGH THE FORECAST AREA MONDAY NIGHT. JET MAX WILL
ALSO BE LOCATED OVER THE NORTHERN PLAINS WITH THE GFS PLACING RIGHT
ENTRANCE REGION OVER THE FORECAST AREA BY 12Z TUESDAY...ECMWF A
LITTLE FURTHER NORTH/SLOWER WITH THE SAME FEATURES. THUS...WILL
COMPROMISE AND INSERT CHANCE/SLIGHT CHANCE THUNDER NORTHERN ZONES
FOR OVERNIGHT ON MONDAY AND INTO TUESDAY MORNING. JET MAX WILL BE
NEAR THE SOUTHERN GREAT LAKES BY TUESDAY AFTERNOON WITH SURFACE HIGH
PRESSURE NOSING IN FROM THE NORTHWEST. GFS SPINS UP A SUSPICIOUS
VORTICITY MAXIMUM AT 500 MB BETWEEN 18Z AND 00Z OVER NORTH CENTRAL
KANSAS AND LOOKS OVERDONE WITH ITS PRECIPITATION. WITH SUBSIDENCE AT
JET LEVEL AND NO LOW LEVEL WARM ADVECTION...WILL END PRECIPITATION
CHANCES IN THE MORNING AND KNOCK DOWN TEMPERATURES A CATEGORY OR SO
PER LATEST MEX TRENDS. WEDNESDAY AND THURSDAY FEATURE AN AMPLIFYING
WEST COAST RIDGE PLACING THE FORECAST AREA UNDER A NORTHWEST FLOW.
WILL HAVE TO MONITOR FOR SUBTLE SHORTWAVES IN THAT FLOW TRIGGERING
CONVECTION...BUT FOR NOW THE GFS LIMITS THE ACTIVITY TO THE CENTRAL
AND SOUTHERN ROCKIES. 850 MB THERMAL RIDGE WILL BE WEST OF THE
ROCKIES BOTH DAYS AND WILL TRIM TEMPERATURES CLOSER TO
CLIMATOLOGICAL NORMALS.

.GLD...NONE.

JDK

COZ090>092-KSZ001>004-013>016-027>029-041-042-NEZ079>081-301200-

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE GOODLAND KS
225 PM MDT THU MAY 29 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHWEST KANSAS...EXTREME
SOUTHWEST NEBRASKA...AND EAST CENTRAL COLORADO.

.DAY ONE...TODAY AND TONIGHT

A WIND SHIFT LINE WILL REMAIN NEARLY STATIONARY FROM NEAR MCCOOK
NEBRASKA SOUTHWEST THROUGH ATWOOD...COLBY...SHARONS SPRINGS KANSAS
TO NEAR CHEYENNE WELLS COLORADO. CONVERGENCE ALONG THIS BOUNDARY
COMBINED WITH HOT TEMPERATURES WILL PRODUCE A FEW HIGH BASED
THUNDERSTORMS...A FEW OF WHICH COULD BECOME SEVERE. THE PRIMARY
THREAT WILL BE DAMAGING DOWNBURST WINDS AND LARGE HAIL.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THE CHANCES FOR THUNDERSTORMS WILL INCREASE ACROSS THE AREA THIS
WEEKEND. A COLD FRONT WILL BRING ANOTHER CHANCE FOR THUNDERSTORMS
FRIDAY NIGHT. THIS WILL BE FOLLOWED BY AN UPPER LEVEL DISTURBANCE
CROSSING THE AREA SATURDAY NIGHT AND SUNDAY WHICH WILL TRIGGER
SHOWERS AND THUNDERSTORMS.

ANOTHER WEAK COLD FRONT WILL BRING CHANCES FOR THUNDERSTORMS TO THE
AREA MONDAY NIGHT. FINALLY CHANCES FOR THUNDERSTORMS INCREASE AGAIN
LATE WEDNESDAY AS ANOTHER UPPER AIR DISTURBANCE AND COLD FRONT
APPROACH.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED THIS AFTERNOON THROUGH EARLY
EVENING.

THEDE