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000
FXUS63 KDDC 152040
AFDDDC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
340 PM CDT WED MAY 15 2013

...UPDATED SHORT TERM SECTION...

.SYNOPSIS...
ISSUED AT 1126 AM CDT WED MAY 15 2013

A ZONAL POLAR JET WAS FOUND ACROSS THE FAR NORTHERN CONUS ALONG THE
CANADA BORDER...WITH A FAIRLY PRONOUNCED JET STREAK WITHIN THIS FLOW
ACROSS THE GREAT LAKES REGION. MEANWHILE FARTHER SOUTH...A MID LEVEL
CYCLONE WAS SPINNING ACROSS WEST TEXAS WHICH WAS LIFTING NORTHEAST
INTO SOUTHWESTERN OKLAHOMA. CONVECTION HAS BEEN ONGOING IN SEVERAL
DIFFERENT AREAS OF CENTRAL AND NORTH TEXAS AHEAD OF THIS MID LEVEL
CYCLONE. THIS LOW HAD SOME BAROTROPIC CHARACTERISTICS WITH NO LOWER
TROPOSPHERIC RESPONSE AHEAD OF THE CYCLONE...AND NEGLIGIBLE MID
LEVEL TEMPERATURE GRADIENTS. ANOTHER MUCH MORE COMPACT MID LEVEL
CYCLONE WITH SIMILAR CHARACTERISTICS WAS FOUND ENTERING SOUTHERN
UTAH...WITH NARROW SHORTWAVE RIDGING ACROSS THE FOUR CORNERS REGION
INTO WESTERN COLORADO.

SURFACE OBSERVATIONS AS OF 16Z INDICATED A WEAK FRONTAL PUSH INTO
FAR NORTHERN KANSAS WITH EASTERLY SURFACE FLOW ACROSS SOUTHERN
NEBRASKA. A SURFACE ANTICYCLONE WAS CENTERED ALONG THE SOUTH
DAKOTA-MINNESOTA BORDER. THIS WEAK FRONTAL BOUNDARY MERGED WITH A
LEE TROUGH ACROSS FAR WESTERN KANSAS.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 339 PM CDT WED MAY 15 2013

TONIGHT:
A RESERVOIR OF ABUNDANT LOW LEVEL MOISTURE ACROSS TEXAS AND OKLAHOMA
WILL ADVECT NORTH-NORTHWESTWARD TONIGHT. THE MAIN CHALLENGE IN THE
FORECAST WILL CENTER AROUND DENSE FOG POTENTIAL.  THE LATEST
OFFICIAL FORECAST WILL REFLECT PATCHY FOG, HOWEVER THE POTENTIAL
EXISTS FOR MORE WIDESPREAD DENSE FOG SHOULD 61 TO 63F DEWPOINTS
REACH A MEADE TO BUCKLIN TO STAFFORD LINE BY DAYBREAK. TEMPERATURES
WILL BE SLOW TO FALL THROUGH THE 60S OVERNIGHT GIVEN THE WIND SPEEDS
FROM THE SOUTHEAST 10 TO 12 KNOTS THROUGH 06Z.  WINDS WILL SLACKEN
OFF AFTER 06Z...WHICH IS WHEN TEMPERATURE SHOULD START TO FALL AT
THE SAME TIME DEWPOINT IS RISING DUE TO ADVECTION FROM THE
SOUTHEAST.

THURSDAY:
AREAS OF MORNING FOG AND/OR LOW STRATUS WILL LINGER THROUGH
MID-MORNING BEFORE INSOLATION TAKES OVER AND THE LOW STRATUS
SCATTERS OUT.  THIS WILL LEAVE BEHIND A WARM AND UNUSUALLY HUMID DAY
(COMPARED TO WHAT WE HAVE BEEN RECENTLY USED TO) ACROSS MUCH OF
SOUTHWEST KANSAS. THE MOISTURE FARTHER WEST WILL BE SHALLOWER AND
THUS A PROPENSITY FOR THE MOISTURE TO MIX OUT EASIER AS THE BOUNDARY
LAYER DEEPENS. WEST OF A LIBERAL TO SCOTT CITY LINE...DEWPOINTS WILL
FALL INTO THE UPPER 40S TO NEAR 50 BY LATE AFTERNOON. THIS AIRMASS
WILL CONVERGE WITH THE VERY WARM AND DRY AIRMASS ACROSS NORTHEAST
NEW MEXICO AND EASTERN COLORADO ALLOWING A DRYLINE TO SHARPEN VERY
NEAR THE COLORADO-KANSAS STATE BORDER. THE CONVERGENCE ALONG THE
DRYLINE MAY BE ENOUGH TO PROMOTE ISOLATED TO WIDELY SCATTERED
THUNDERSTORMS. THERE HAVE BEEN SUCCESSIVE NAM12 MODEL RUNS SHOWING A
CONVECTIVE SIGNAL ALONG THE COLORADO-KANSAS BORDER ALONG THE
DRYLINE. WESTERLY MID LEVEL FLOW AROUND 25 KNOTS ALONG WITH
SOUTH-SOUTHEASTERLY LOW LEVEL FLOW OF 15 TO 20 KNOTS WILL SUPPORT
WELL-ORGANIZED SEVERE LOCAL STORMS. DESPITE THE MIX-OUT OF LOW LEVEL
MOISTURE JUST EAST OF THE DRYLINE INTO THE 48-52F RANGE...THIS WILL
STILL RESULT IN SBCAPE OF 1000-1300 J/KG AND A 0-3KM AGL
ENERGY-HELICITY INDEX OF AROUND 1. A HIGH-BASED SUPERCELL COULD
THRIVE FOR A COUPLE HOURS IN THIS ENVIRONMENT CAPABLE OF DAMAGING
DOWNBURST WINDS AND HALF-DOLLAR SIZE HAIL...BEFORE DISSIPATING NOT
TOO LONG AFTER SUN DOWN.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 302 PM CDT WED MAY 15 2013

FRIDAY:

THERE WILL BE NEUTRAL TO SLIGHTLY POSITIVE 500 HPA GEOPOTENTIAL HEIGHT
TENDENCIES ON FRIDAY. AT THE SURFACE, A LEE TROF WILL CONTINUE ACROSS
THE HIGH PLAINS OF COLORADO. THIS TROF WILL RESULT IN A CONTINUED WARM
AIR ADVECTION PATTERN WITH DEWPOINTS IN THE UPPER 50S TO LOWER 60S
ADVECTING IN ACROSS THE REGION. MEANWHILE, 700 HPA TEMPERATURES WILL
CONTINUE TO INCREASE THROUGH THE DAY (POSSIBLY TO 12C!). WITH SUCH WARM
LOW LEVEL TEMPERATURES AND LACK OF AN UPPER LEVEL TRIGGER, AM NOT EXPECTING
ANY CONVECTION FOR THE DAY. WILL HAVE TO WATCH OUT FOR STRATUS EARLY
IN THE MORNING AND HOW LONG THE STRATUS/STRATOCUMULUS STICKS AROUND.
THE 12Z NAM IS VERY AGGRESSIVE WITH HIGH 850 HPA RELATIVE HUMIDITIES
AND RESULTANT IMPACTS TO SURFACE TEMPERATURES. DECREASED MAXIMUM TEMPERATURES
A BIT, BUT NOWHERE NEAR AS AGGRESSIVE AS THE NAM SUGGESTS. HIGHS SHOULD
BE MAINLY IN THE 80S WITH LOWS IN THE 60S HEADING INTO SATURDAY MORNING.

SATURDAY:

UPPER LEVEL FLOW INCREASES SLIGHTLY SATURDAY AHEAD OF AN APPROACHING
TROF. THIS RESULTS IN INTENSIFYING LEE CYCLOGENESIS ACROSS WESTERN KANSAS
THROUGH THE DAY. MID LEVEL COOLING, LIFT, AND CONVERGENCE ALONG AN ASSOCIATED
DRYLINE WILL RESULT IN THE POSSIBILITY FOR CONVECTION. THE 12Z GFS IS
FARTHER WEST WITH THE DRYLINE THAN COMPARED TO THE 12Z ECMWF. BOTH MODELS
DO SHOW CONVECTION BREAKING OUT ACROSS THE REGION BY LATE AFTERNOON.
SEVERE THUNDERSTORMS ARE NOW IN QUESTION AS 12Z NWP IS LAGGING WITH
THE UPPER LEVEL JET. BULK SHEAR FROM BOTH ECMWF/GFS IS WEAK (20 KT),
SO NOT SURE IF CONVECTION WILL BE VERY ORGANIZED OR NOT. THERE STILL
IS A LOT OF UNCERTAINTY SINCE THE ECMWF IS FARTHER EAST WITH THE DRYLINE
THAN COMPARED TO THE GFS. THE OTHER CONCERN IS TEMPERATURES IN THE WAKE
OF THE DRYLINE... TEMPS SHOULD BE VERY WARM TO HOT AS DOWNSLOPE SOUTHWESTERLY
WINDS AND COMPRESSIONAL WARMING DEVELOP. LOOK FOR HIGHS IN THE 90S AND
LOWS IN THE 60S.

SUNDAY AND BEYOND:

NOT MUCH CONFIDENCE IN THE EXTENDED. IF THE SYNOPTIC WAVE IS SLOWER,
THEN THUNDERSTORMS WILL STILL BE POSSIBLE ON SUNDAY ACROSS KANSAS. A
DRIER FORECAST IS EXPECTED LATE MONDAY INTO TUESDAY AS THE WAVE MOVES
NORTHEAST OF THE REGION AND A COOLER AIRMASS SETTLES ACROSS SOUTHWEST
KANSAS. TEMPERATURES WILL BECOME MORE SEASONAL WITH HIGHS IN THE
70S OR 80S AND LOWS IN THE 50S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1126 AM CDT WED MAY 15 2013

VFR FLIGHT CATEGORY IS EXPECTED THE REMAINDER OF THE AFTERNOON AND
MUCH OF THE OVERNIGHT HOURS WITH A PREVAILING SOUTHEAST WIND 10 TO
13 KNOTS. THE PERSISTENT SOUTHEAST WINDS WILL ALLOW RICH LOW LEVEL
MOISTURE TO MOVE INTO SOUTH CENTRAL AND PORTIONS OF SOUTHWEST KANSAS
AFTER AROUND 09Z THURSDAY. THE 09-15Z TIME FRAME WILL BE A DIFFICULT
FORECAST FOR FLIGHT CATEGORY AS SOME LOW STRATUS MAY DEVELOP AS THE
MOISTURE MOVES IN. WILL LIKELY GO AHEAD AND FORECAST A 3 TO 5
HOUR PERIOD OF IFR AT DDC DURING THIS TIME FRAME FOR THE 18Z TAF
UPDATE...BUT KEEP GCK AND HYS IN IFR FOR NOW AS BY THE TIME THE
MOISTURE MAKES IT TO THESE AREAS...INSOLATION WILL WARM THINGS UP
PREVENTING A LOW CEILING.


&&

.PRELIMINARY POINT TEMPS/POPS...
DDC  60  86  63  85 /  10  10  10  10
GCK  59  87  62  86 /  10  20  20  10
EHA  58  90  60  91 /  10  20  20  10
LBL  60  89  62  90 /  10  20  10  10
HYS  60  84  63  83 /  10  20  10  10
P28  63  82  65  83 /  20  10  10  10

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...SUGDEN
AVIATION...UMSCHEID