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000
FXUS63 KDDC 180700
AFDDDC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
200 AM CDT SAT MAY 18 2013

...UPDATE TO SHORT TERM...

.SYNOPSIS...
ISSUED AT 1050 PM CDT FRI MAY 17 2013

WV IMAGERY AND 00Z UPPER AIR ANALYSIS INDICATE A WEAK UPPER LEVEL
RIDGE OF HIGH PRESSURE TRANSITIONING EAST ACROSS THE CENTRAL PLAINS.
MEANWHILE, AN UPPER LEVEL TROUGH OF LOW PRESSURE IS MOVING EAST INTO
THE FOUR CORNERS REGION. NEAR THE SURFACE, AN AREA OF LOW PRESSURE
IS SITUATED ACROSS EXTREME SOUTHEASTERN COLORADO WITH AN ATTENDANT
DRYLINE EXTENDING SOUTHWARD INTO FAR WESTERN PORTIONS OF THE TEXAS
PANHANDLE. MOISTURE CONTINUES TO SLOWLY ADVECT NORTHWESTWARD INTO
THE CENTRAL AND WESTERN HIGH PLAINS WITH SURFACE DEWPOINTS UP INTO
THE LOWER TO MID 60S(F) ACROSS CENTRAL AND MUCH OF SOUTHWEST KANSAS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 200 AM CDT SAT MAY 18 2013

SHORT RANGE MODELS INDICATE THE UPPER LEVEL TROUGH IN THE FOUR
CORNERS REGION PUSHING FURTHER EAST INTO THE CENTRAL AND SOUTHERN
ROCKIES TODAY SETTING THE STAGE FOR SHOWERS AND THUNDERSTORMS FROM
THE NORTHERN PLAINS SOUTHWARD INTO THE CENTRAL PLAINS OF KANSAS. AS
THE UPPER LEVEL TROUGH APPROACHES, A JET CORE EXITING THE TROUGH
AXIS IS PROJECTED TO MOVE EAST INTO THE WESTERN HIGH PLAINS BY MID
TO LATE AFTERNOON PROVIDING FAVORABLE DYNAMIC SUPPORT ALOFT,
INCLUDING STRONG DIVERGENT FIELDS ACROSS CENTRAL AND WESTERN KANSAS.
MEANWHILE, A STRENGTHENING SURFACE LOW IN SOUTHEASTERN COLORADO,
ACCOMPANIED BY THE SHARP DRYLINE EXTENDING SOUTHWARD, IS EXPECTED
TO EDGE SLOWLY EASTWARD INTO SOUTHWEST KANSAS THIS AFTERNOON
ENHANCING LOW LEVEL CONVERGENCE ACROSS SOUTHWEST KANSAS INITIALLY,
THEN EASTWARD ACROSS CENTRAL KANSAS. NAM/GFS MODEL SOUNDINGS SHOW
SUBSTANTIAL INSTABILITY ACROSS CENTRAL AND SOUTHWEST KANSAS WITH
CAPE VALUES WELL IN EXCESS OF 4000 J/KG BY THE AFTERNOON HOURS.
THE MODEL SOUNDINGS ALSO INDICATE FAVORABLE DEEP LAYER SHEAR
PROFILES INCREASING AS LOWER LEVEL LAPSE RATES STEEPEN THROUGHOUT
THE AFTERNOON. AS A RESULT, STRONG TO SEVERE THUNDERSTORM
DEVELOPMENT WILL BE POSSIBLE ACROSS CENTRAL AND PORTIONS OF
SOUTHWEST KANSAS LATE THIS AFTERNOON THROUGH THIS EVENING WITH
THE POTENTIAL EXISTING FOR VERY LARGE HAIL AND DAMAGING WINDS.
ADDITIONALLY, THE SHEAR PROFILE IS SUCH THAT TORNADOES MAY BE
POSSIBLE WITH THE STRONGEST OF STORMS, ESPECIALLY INTO THE EVENING
ONCE A STRONG LOW LEVEL JET DEVELOPS AHEAD OF THE SURFACE LOW.

TEMPERATURES WILL ONCE AGAIN CLIMB ABOVE NORMAL TODAY AS THE SURFACE
LOW IN SOUTHEASTERN COLORADO CONTINUES TO INFLUENCE A SOUTH TO
SOUTHEASTERLY LOW LEVEL FLOW INTO WESTERN KANSAS. TEMPERATURES AT
H85 WILL REMAIN SIMILAR TO YESTERDAY WITH VALUES RANGING FROM AROUND
TO JUST ABOVE 20C IN CENTRAL KANSAS TO NEAR 30C IN FAR SOUTHWEST
KANSAS. EXPECT HIGHS UP INTO THE 80S(F) IN CENTRAL KANSAS WITH THE
LOWER TO MID 90S(F) POSSIBLE IN EXTREME SOUTHWEST KANSAS, ESPECIALLY
ONCE THE DRYLINE MOVES THROUGH THIS AFTERNOON. LOOK FOR LOWS BACK
DOWN INTO THE 60S(F) WITH MID TO UPPER 50S(F) POSSIBLE NEAR THE
COLORADO BORDER AS A LOW LEVEL NORTHERLY FLOW SETS UP BEHIND THE
ADVANCING SURFACE LOW.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 413 AM CDT FRI MAY 17 2013

SATURDAY INTO SATURDAY NIGHT CONTINUE TO LOOK LIKE AN ACTIVE
WEATHER PERIOD ACROSS THE GREAT PLAINS AS THE UPPER TROUGH CURRENTLY
DIGGING INTO THE WEST COAST, SWINGS EAST INTO THE ROCKIES. THIS IS
IN RESPONSE TO A 100+ KNOT JET STREAK ON THE BACK SIDE OF THE WAVE
THIS MORNING, BEGINNING TO ROUND THE BASE OF THE TROUGH ON SATURDAY.
THE ARRIVAL OF THIS SYSTEM WILL PUSH A PACIFIC FRONT EASTWARD INTO
THE PLAINS AND STRETCH FROM THE DAKOTAS INTO EASTERN COLORADO
WHILE ALSO INDUCING STRONG LOW-LEVEL CYCLOGENESIS OVER NORTHWEST
KANSAS SATURDAY AFTERNOON. A DRYLINE EXTENDING SOUTH OF THIS CYCLONE
WILL SLIP EASTWARD INTO WESTERN KANSAS BY MID AFTERNOON ROUGHLY
ALONG THE HIGHWAY 83 CORRIDOR. THIS BOUNDARY WILL BE THE DIVIDING
LINE BETWEEN TWO EXPECTED EXTREMES OF HIGH IMPACT WEATHER.

ON THE MOIST SIDE OF THE BOUNDARY, UPPER 50 TO MID 60 DEGREE
DEWPOINTS ALONG WITH TEMPERATURES IN THE 90S WILL RESULT IN HIGH TO
EXTREME INSTABILITY VIA MLCAPE VALUES OF 3000-3500 J/KG EXPECTED BY
MID AFTERNOON. A STRONG ELEVATED MIXED LAYER WILL REMAIN OVER THE
CENTRAL PLAINS VIA 700 HPA TEMPERATURES OF +12C TO +14C WITH THIS
EML EFFECTIVELY CAPPING THE ATMOSPHERE THROUGH MOST OF THE DAY.
HOWEVER, AS THE WAVE APPROACHES THE PLAINS BY LATE AFTERNOON, LARGE
SCALE ASCENT AND MID/UPPER LEVEL HEIGHT FALLS MAY ERODE ENOUGH OF
THE CAP TO GENERATE ISOLATED TO POSSIBLY SCATTERED CONVECTION EAST
OF HIGHWAY 83 ALTHOUGH WOULD NOT BE SHOCKED IF CONVECTION FAILS TO
GENERATE. OVERALL SEVERE CONVECTIVE POTENTIAL IS HIGHLY CONDITIONAL
NOT ONLY ON CONVECTIVE COVERAGE BUT ALSO DUE TO STRONGER 6-12 KM AGL
WINDS REMAINING BEHIND THE DRYLINE. NONETHELESS, SHEAR PROFILES ARE
MODESTLY FAVORABLE FOR ROTATING UPDRAFTS AND ANY SUPERCELL LASTING
FOR MORE THAN AN HOUR COULD PRODUCE HAIL UP TO BASEBALL SIZE
ALONG WITH AN ISOLATED TORNADO.

ON THE DRY SIDE OF THE BOUNDARY, POTENTIAL EXISTS FOR CRITICAL FIRE
WEATHER CONDITIONS ACROSS FAR SOUTHWEST KANSAS. DEEP THERMAL MIXING
BEHIND THE DRYLINE WILL RESULT IN TEMPERATURES IN THE MID TO UPPER
90S COMBINING WITH DRY AIR TO PRODUCE MINIMUM HUMIDITY LEVELS OF
10-15 PERCENT FOR SEVERAL HOURS DURING THE AFTERNOON TO EARLY
EVENING. THIS ALONG WITH WIND GUSTS ABOVE 25 MPH IN THE AFTERNOON
COULD PRODUCE RED FLAG CONDITIONS FOR A SEVERAL HOURS AND OPTED TO ISSUE
A FIRE WEATHER WATCH FOR LOCATIONS GENERALLY WEST OF HIGHWAY 83.

SUNDAY AND SUNDAY NIGHT WILL REMAIN ACTIVE OVER THE GREAT PLAINS AS
THE AFOREMENTIONED JET STREAK CONTINUES TO DIVE SOUTHEAST INTO THE
BASE OF THE UPPER TROUGH.  THE EXIT REGION OF THIS JET WILL CONTINUE
TO DEEPEN THE SURFACE LOW INITIALLY OVER WESTERN KANSAS SUNDAY
MORNING ALTHOUGH IT SHOULD LIFT QUICKLY NORTHEAST INTO THE NORTHERN
PLAINS BY SUNDAY EVENING. THIS WILL ALLOW AN ASSOCIATED PACIFIC
FRONT TO PUSH SOUTHEAST THROUGH WESTERN KANSAS BY EARLY AFTERNOON
ON SUNDAY. UNDER THIS SCENARIO DEEPER MOISTURE WILL BE SHUNTED INTO
THE EASTERN HALF OF KANSAS LEAVING ONLY WEAK CONDITIONAL
INSTABILITY OVER THE WESTERN HALF OF THE STATE. CAN/T COMPLETELY
RULE OUT SOME HIGHER BASED THUNDERSTORMS WITH THE INITIAL FRONTAL
PASSAGE SUNDAY BUT SUNDAY EVENING TO OVERNIGHT LOOK DRY FOR
PORTIONS OF KANSAS WEST OF HIGHWAY 281. OTHERWISE, TEMPERATURES
WILL BE SLIGHTLY COOLER BEHIND THE FRONT FOR SUNDAY WITH HIGHS IN
THE 80S ANTICIPATED.

MONDAY INTO TUESDAY WILL TURN QUIET AS THE REMNANT CLOSED
CIRCULATION FROM THE WEEKEND SYSTEM, SLOWLY WOBBLES AROUND THE
NORTHERN PLAINS. THE PACIFIC FRONT SHOULD STALL OVER THE SOUTHERN
PLAINS LEAVING DEEPER MOISTURE TRAPPED WELL SOUTH OF KANSAS.
HOWEVER, JET DYNAMICS MAY PRODUCE ENOUGH ASCENT TO TRIGGER SOME
WEAK HIGH BASED THUNDERSTORMS ON MONDAY BUT THEN DRY FOR TUESDAY
WITH HIGHS GENERALLY IN THE 70S TO LOWER 80S BOTH DAYS. QUESTIONS
STILL EXIST FOR WEDNESDAY INTO THURSDAY WITH THE EVOLUTION OF THE
UPPER PATTERN ALTHOUGH THEY GENERALLY AGREE ON A RIDGE BUILDING OVER
THE PLAINS AS A TROUGH DIGS INTO THE PACIFIC NORTHWEST. WHETHER
THE LEE TROUGH CAN DEEPEN ENOUGH UNDER THIS SETUP TO PULL THE
FRONT AND ASSOCIATED DEEPER MOISTURE BACK NORTH INTO KANSAS FOR
THUNDERSTORM DEVELOPMENT IS UNKNOWN. WILL LEAVE THIS PORTION OF
THE FORECAST RELATIVELY UNCHANGED DUE TO THE UNCERTAINTIES EXISTING
AT THIS POINT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1202 AM CDT SAT MAY 18 2013

LOW LEVEL STRATUS IS EXPECTED TO DEVELOP ACROSS SOUTH CENTRAL AND
PORTIONS OF SOUTHWEST KANSAS OVERNIGHT AS RELATIVE HUMIDITY LEVELS
RISE WITHIN A SOUTHEASTERLY UPSLOPE FLOW. MVFR CIGS/VSBYS ARE
EXPECTED TO DEVELOP AT ALL TAF SITES THROUGH DAYBREAK WITH BRIEF
PERIODS OF IFR CIGS POSSIBLE AGAIN TOWARD SUNRISE. THE CIGS ARE
EXPECTED TO LIFT SLOWLY BEGINNING GENERALLY AFTER 14Z WITH VFR
CONDITIONS RETURNING BY EARLY AFTERNOON. AS FOR WINDS, SURFACE LOW
PRESSURE ACROSS EXTREME SOUTHEASTERN COLORADO WILL CONTINUE TO
INFLUENCE SOUTH TO SOUTHEASTERLY WINDS OF 10 TO 25KT ACROSS WESTERN
KANSAS THROUGH LATE THIS MORNING. THE WINDS WILL BECOME MORE
SOUTHWESTERLY ACROSS EXTREME SOUTHWEST KANSAS SATURDAY AFTERNOON
AS THE SURFACE LOW BEGINS TO EDGE SLOWLY EAST ACROSS THE COLORADO
BORDER INTO KANSAS.

&&

.PRELIMINARY POINT TEMPS/POPS...
DDC  90  60  83  55 /  20  40  20  10
GCK  90  58  81  52 /  20  20  20  10
EHA  95  57  81  53 /   0  10  10  10
LBL  95  58  84  53 /  10  10  10  10
HYS  88  63  81  55 /  30  60  30  20
P28  88  65  87  60 /  30  60  20  20

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM 1 PM CDT /NOON MDT/ THIS AFTERNOON
THROUGH THIS EVENING FOR KSZ061-062-074-075-084-085.

&&

$$

SHORT TERM...JJOHNSON
LONG TERM...AJOHNSON
AVIATION...JJOHNSON