Area Forecast Discussion
Issued by NWS Dodge City, KS

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625
FXUS63 KDDC 210906
AFDDDC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
406 AM CDT THU MAY 21 2015

...UPDATED AVIATION SECTION...

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT THU MAY 21 2015

ONLY A VERY SHALLOW MIXED BOUNDARY LAYER WILL EXIST TODAY AS SURFACE
HIGH PRESSURE MAINTAINS INFLUENCE OVER SENSIBLE WEATHER. THE
FORECAST AREA WILL REMAIN UNDER THE EASTERN HALF OF THE UPPER RIDGE;
REMAINING WEAKLY SUBSIDENT OR NEUTRAL WITH RESPECT TO VERTICAL
MOTIONS.  LIGHT AND VARIABLE WINDS THIS MORNING WILL GIVE WAY TO
LIGHT SOUTHEAST WINDS DURING THE AFTERNOON AS THE SURFACE HIGH
EXPANDS ACROSS EASTERN KANSAS AND WESTERN MO.

THE NEXT WAVE THAT WILL AFFECT THE AREA WITH RAIN SHOULD LIFT INTO
WESTERN KANSAS IN THE EVENING HOURS. EASTERLY UPSLOPE FLOW AND
ISENTROPIC LIFT IN A VERY LOW INSTABILITY ENVIRONMENT SHOULD ACCOUNT
FOR MAINLY RAIN/SHRA AND ISOLATED THUNDERSTORMS THROUGH THE
OVERNIGHT. MODEL OUTPUT VARIES BETWEEN A QUARTER INCH AND THREE
QUARTER OF AN INCH OF RAIN.

ALTHOUGH NOT AS COOL AS WEDNESDAY WAS, THE SHORT TERM WILL CONTINUE
TO SEE BELOW CLIMATOLOGICAL HIGHS TODAY. MODELS ONLY FORECAST MID
60S UNDER THIS HIGH PRESSURE THIS AFTERNOON AND NEAR NORMAL
OVERNIGHT LOWS IN THE 40S.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 325 PM CDT WED MAY 20 2015

THE FORECAST CONTINUES TO BE A HUGE CHALLENGE GOING INTO THE
WEEKEND, ESPECIALLY REGARDING TEMPERATURES SATURDAY AND WHETHER OR
NOT WE WILL SEE SEVERE WX ANYWHERE ACROSS OUR AREA (SPOILER
ALERT: MOST LIKELY NOT).

TWO MORE COHERENT PRECIPITATION EVENTS ARE UPCOMING: THURSDAY
NIGHT/FRIDAY MORNING AND AGAIN SATURDAY.  THE FIRST EVENT WILL BE
TIED TO A LEAD SHORTWAVE TROUGH EJECTING NORTHEAST AHEAD OF THE
PRIMARY UPPER LOW TAKING SHAPE JUST OFF THE COAST OF SOUTHERN
CALIFORNIA. THIS EVENT WILL EVOLVE NOT TOO DISSIMILAR TO YESTERDAY`S
PRECIP EVENT..IN THAT A SHIELD OF RAIN WILL DEVELOP ACROSS WEST
TEXAS/TX PANHANDLE AND ADJACENT NORTHEAST NEW MEXICO...EXTENDING
INTO EASTERN COLORADO ALONG A ZONE OF FAIRLY STRONG 800-700MB WARM
FRONTOGENESIS. THIS WILL CONTINUE TO MOVE NORTHEAST INTO SOUTHWEST
KANSAS DURING THE OVERNIGHT HOURS.  WE WILL BE GOING WITH
CATEGORICAL POPS FOR MUCH OF THE AREA NOW FOR THE THURSDAY NITH
PERIOD (80+ PERCENT). RAINFALL TOTALS WITH THIS EVENT SHOULD BE LESS
THAN TUESDAY AS THIS LEAD WAVE AND ASSOCIATED LIFT WILL MOVE THROUGH
FAIRLY QUICKLY.

SOME VERY LIGHT RAIN OR DRIZZLE WILL LIKELY CONTINUE THROUGH THE DAY
FRIDAY WITH LOW LEVEL SOUTHEASTERLY COOL, MOIST UPSLOPE CONTINUING.
MEANWHILE, THE ECMWF CONTINUES TO SHOW ANOTHER LARGE ROUND OF
CONVECTIVE ACTIVITY FRIDAY ACROSS NORTHWEST TEXAS INTO OKLAHOMA,
WHICH WILL REINFORCE THE BOUNDARY DOWN THERE. ABOVE THE SURFACE, WE
WILL SEE A CONTINUED ADVECTION OF GULF MOISTURE INTO WESTERN KANSAS,
WHICH WILL TRANSLATE INTO A LARGE AREAL EXTENT OF STRATUS WITH THE
LOWER TROPOSPHERE REMAINING COOL. THE ECMWF AND GFS COMPLETELY
DIFFER BY FRIDAY NIGHT INTO SATURDAY. THE GFS40 BEGINS TO SHEAR OUT
THE UPPER LOW INTO A POSITIVELY TILTED TROUGH AXIS FROM ARIZONA INTO
WYOMING WITH THE ECMWF HANGING ONTO AN UPPER LOW CENTER ALONG THE
ARIZONA-UTAH BORDER. THIS IS THE BASIC REASONING BEHIND THE
DIFFERING OF SOLUTIONS AND WHY THE GFS40 IS SO AGGRESSIVE WITH THE
LOWER TROPOSPHERIC FLOW INTO WESTERN KANSAS AND NEBRASKA...WARMING
THE 850MB LEVEL UP IN THE PROCESS. THE SLOWER, DEEPER ECMWF SOLUTION
RESULTS IN 850MB REFLECTION ACROSS EAST-CENTRAL NEW MEXICO...WITH AN
EFFECTIVE BACKING OF THE LOWER TROPOSPHERIC FLOW NORTH AND EAST
ACROSS TEXAS PANHANDLE AND INTO SOUTHWEST KANSAS. THIS SCENARIO
KEEPS THE COOL, MOIST AIRMASS IN CHECK ACROSS THE CENTRAL HIGH
PLAINS, AND IS THE SCENARIO WHICH MAKES MORE SENSE GIVEN PAST
EXPERIENCE WITH THE SKILL OF THE ECMWF IN HANDLING SOUTHWEST LOWS
AT THE D+2 TO D+5 TIME FRAME. AS THE LOW APPROACHES SATURDAY, IT
WILL BEGIN TO LIFT OUT ACROSS THE ROCKIES...AND VIGOROUS
CONVECTION IS SUGGESTED BY THE ECMWF SATURDAY FROM WEST TEXAS NEAR
THE 850MB ZONE OF WARM FRONTOGENESIS INTO OKLAHOMA ALONG THE
SURFACE WARM FRONTOGENETIC ZONE. THE GFS MODEL JUST DOES NOT
APPEAR TO BE A REASONABLE SOLUTION AS ITS PERFORMANCE HAS BEEN
POOR AGAINST THE ECMWF IN THIS REGIME OVER THE PAST COUPLE OF
WEEKS.

THE END RESULT ON SATURDAY FOR SOUTHWEST KANSAS WILL LIKELY BE
COOLER TEMPERATURES, MUCH MORE CLOUD COVER, AND PERIODIC
PRECIPITATION INCLUDING DRIZZLE. TEMPERATURES WERE LOWERED SOME, BUT
WE COULD NOT LOWER DOWN TO THE COLDEST ECMWF SOLUTION DUE TO
RELUCTANCE OF NEIGHBORING OFFICES TO JUMP OFF THE SUPERBLEND
GUIDANCE MUCH (WHICH SHOWS UPPER 60S TO LOWER 70 HIGHS GIVEN SUCH
NCEP INFLUENCE). I EXPECT THE NCEP MODELS TO TREND TOWARD THE
ECMWF AS WE GET CLOSER TO SATURDAY. THE LACK OF CAPE, AS A RESULT,
WILL LEAD TO A LACK OF SEVERE WEATHER ACROSS SOUTHWEST KANSAS AS
IT APPEARS BASED ON THE ECMWF...WITH ANOTHER SEVERE
WEATHER/ONGOING FLOODING EPISODE LIKELY FROM NORTHWEST TEXAS INTO
SOUTHERN OKLAHOMA.

BEYOND SATURDAY...THE MAIN UPPER LOW WILL LIFT NORTH-NORTHEAST AS
ANOTHER PERTURBATION DIGS INTO THE BASE OF THE UPPER TROUGH ACROSS
NORTHERN MEXICO. THE MAIN 500MB TROUGH AXIS, AS SHOWN BY THE ECMWF,
WILL REMAIN WEST OF SOUTHWEST KANSAS THROUGH MONDAY...AND AS LONG AS
IT REMAINS WEST OF US, WE WILL KEEP GOOD CHANCES OF PRECIPITATION
GOING. THE AIRMASS WILL VERY SLOWLY MODIFY THROUGH MONDAY...BUT IT
WILL TAKE SOME SUSTAINED STRONG WESTERLY MOMENTUM IN THE MID
TROPOSPHERE TO ERODE THIS COOL AIRMASS. THIS MAY FINALLY OCCUR BY
MID NEXT WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 106 AM CDT THU MAY 21 2015

MVFR STRATUS WILL PERSIST FOR AT LEAST PART OF THE OVERNIGHT HOURS,
OR MOST OF IT. THE LATEST MODEL GUIDANCE AND MOS OUTPUT ONLY HAS THE
STRATUS SITUATION IMPROVING THROUGH THE MORNING IF ANY TREND AT ALL,
AS DRIER AIR FROM THE SURFACE ANTICYCLONE INFLUENCES WESTERN KS. A
SURGE OF HIGHER DEW POINTS AND SURFACE UPSLOPE/ISENTROPIC LIFT WILL
BRING A RETURN TO SHOWERS LATER THIS EVENING.


&&

.PRELIMINARY POINT TEMPS/POPS...
DDC  64  48  59  53 /  10 100 100  50
GCK  63  48  60  52 /  10 100  90  50
EHA  61  48  66  55 /  10  80  70  40
LBL  65  49  63  56 /  10 100  90  40
HYS  63  47  59  52 /  10  60  70  50
P28  66  50  61  55 /  10  80  90  60

&&

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

$$

SHORT TERM...RUSSELL
LONG TERM...UMSCHEID
AVIATION...RUSSELL



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