000
FXUS63 KDDC 171807
AFDDDC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
107 PM CDT FRI MAY 17 2013

...UPDATED AVIATION SECTION FOR 18Z TAFS...

.SYNOPSIS...
ISSUED AT 1100 PM CDT THU MAY 16 2013

WV IMAGERY AND 00Z UPPER AIR ANALYSIS INDICATE AN UPPER LEVEL
SHORTWAVE TROUGH LIFTING EAST-NORTHEAST ACROSS THE CENTRAL PLAINS
OF NEBRASKA. MEANWHILE, A WEAK UPPER LEVEL RIDGE OF HIGH PRESSURE
IS MOVING SLOWLY EAST ACROSS THE ROCKIES INTO THE WESTERN HIGH
PLAINS. NEAR THE SURFACE, MODEST LOW LEVEL MOISTURE IS ADVECTING
NORTHWEST INTO THE CENTRAL AND WESTERN HIGH PLAINS WITH SURFACE
DEWPOINTS WELL UP INTO THE 50S(F) ACROSS MUCH OF CENTRAL AND
SOUTHWEST KANSAS. THIS MOISTURE IS POOLING AHEAD OF A DRYLINE THAT
EXTENDS FROM SOUTHEASTERN COLORADO SOUTHEASTWARD INTO THE FAR
WESTERN PORTION OF THE TEXAS PANHANDLE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 100 AM CDT FRI MAY 17 2013

SHORT RANGE MODELS INDICATE THE UPPER LEVEL SHORTWAVE ACROSS
NEBRASKA LIFTING FURTHER EAST-NORTHEAST INTO THE UPPER MIDWEST
TODAY. MEANWHILE, THE WEAK UPPER LEVEL RIDGE COMING OUT OF THE
ROCKIES WILL PUSH FURTHER EAST ACROSS THE CENTRAL PLAINS. ALTHOUGH
AVAILABLE INSTABILITY WILL BE AMPLE WITH NAM/GFS MODEL SOUNDINGS
SHOWING WELL ABOVE 2,000 TO 2,500 J/KG, A FAIRLY WEAK FLOW ALOFT
ALONG WITH SIGNIFICANT CAPPING WILL HINDER PRECIP CHANCES TODAY.
TEMPERATURES WILL REMAIN ABOVE NORMAL TODAY AS SURFACE TROUGHING
IN EASTERN COLORADO STRENGTHENS. THIS WILL ENHANCE SLIGHT WARM
AIR ADVECTION WITHIN A LOW LEVEL SOUTH TO SOUTHEASTERLY LOW LEVEL
FLOW ACROSS WESTERN KANSAS. THE NAM AND GFS SHOW H85 SLIGHTLY HIGHER
H85 TEMPERATURES COMPARED TO YESTERDAY WITH AROUND 18C TO 20C ACROSS
CENTRAL KANSAS TO NEAR 30C IN EXTREME SOUTHWEST KANSAS. WITH STEEP
LAPSE RATES DEVELOPING IN THE LOWER LEVELS BY THIS AFTERNOON, LOOK
FOR HIGHS WELL UP INTO THE 80S(F) ACROSS CENTRAL AND PORTIONS OF
SOUTHWEST KANSAS. THE LOWER TO MID 90S(F) ARE POSSIBLE IN EXTREME
SOUTHWEST KANSAS.

.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 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 104 PM CDT FRI MAY 17 2013

A SIGNIFICANT AMOUNT OF LOW LEVEL MOISTURE WILL MOVE INTO
SOUTHWEST KANSAS TONIGHT. THIS WILL RESULT IN THE WIDESPREAD
DEVELOPMENT OF DENSE FOG...PARTICULARLY IN THE 08-13Z TIME FRAME
LATE TONIGHT/EARLY SATURDAY MORNING. WILL CARRY ONE-QUARTER MILE
VISIBILITY IN THE TAF FOR DDC AND GCK TERMINALS. DENSE FOG WILL
ERODE SHORTLY AFTER SUNRISE...BUT LOW STRATUS MAY PERSIST IN THE
HYS AREA THROUGH LATE MORNING.

&&

.PRELIMINARY POINT TEMPS/POPS...
DDC  63  91  60  85 /  10  30  30  10
GCK  62  93  58  83 /  10  20  20  10
EHA  62  94  58  84 /  10  10  10  10
LBL  62  97  58  86 /  10  10  10  10
HYS  63  90  63  83 /  10  30  30  30
P28  65  91  65  88 /  10  30  30  20

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR KSZ061-062-074-075-084-085.

&&

$$

SYNOPSIS...JJOHNSON
SHORT TERM...JJOHNSON
LONG TERM...AJOHNSON
AVIATION...UMSCHEID