Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 050828
AFDGLD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
228 AM MDT TUE MAY 5 2015

.UPDATE...
ISSUED AT 1023 PM MDT MON MAY 4 2015

UPDATED FORECAST TO REFLECT THE DIMINISHED CHANCES FOR RAINFALL
FOR THE WESTERN HALF OR SO OF THE AREA THROUGH THE REST OF THE
NIGHT. WAS VERY CONFIDENT EARLIER THAT THE LINE OF STORMS WOULD
MOVE ACROSS THE ENTIRE AREA...WITH SOME WEAKENING OVER THE EAST
PART OF THE AREA. HOWEVER OVER THE LAST HOUR OR SO THE LINE OF
STORMS HAS ALMOST COMPLETELY DISSIPATED.

LOOKING AT RUC THETA-E AT 850MB...THERE IS DRIER AIR OVER THE
WESTERN HALF OF THE AREA. AM THINKING THIS IS WHY THE STORMS DIED
OVER THE WEST INSTEAD OF THE EAST WHICH HAS HIGHER THETA-E AND
BETTER CAPE.

LOOKING SOUTHWARD NUMEROUS SHOWERS AND SOME T-STORMS CONTINUE
TO MOVE UP FROM THE SOUTH IN THE HIGHER THETA-E AIR. LIFT DOES
DECLINE OVER THE EAST OVERNIGHT SO HAVE RAINFALL CHANCES TRENDING
ACCORDINGLY. DOES LOOK LIKE THE EAST HALF WILL HAVE A MUCH BETTER
CHANCE FOR RAINFALL DUE TO THE HIGHER THETA-E AIR PRESENT.

MEANWHILE PATCHY FOG IS EXPECTED OVER THE NORTHERN HALF OR SO OF
THE AREA OVERNIGHT INTO TUESDAY MORNING. LOOKS LIKE THE FOG WILL
BE NORTH OF THE SLOWLY ADVANCING SURFACE BOUNDARY.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 220 PM MDT MON MAY 4 2015

EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW
DEEPENING TROUGH OVER SOUTHERN CALIFORNIA WITH SW FLOW FROM THE GULF
OF ALASKA AND ACROSS THE CENTRAL/HIGH PLAINS. MOIST PLUME EXTENDS
FROM THE GREAT BASIN ACROSS THE OHIO RIVER VALLEY WITH ADDITIONAL
MOISTURE FEEDING IN THE PLAINS FROM THE GULF OF MEXICO. AT THE
SURFACE A STATIONARY FRONT EXTENDS FROM NORTHEAST KANSAS TO
SOUTHEAST COLORADO AND LIES JUST SOUTHEAST OF OUR CWA...WITH
BAROCLINIC ZONE EXTENDING NORTH INTO THE SE PART OF OUR CWA.
THUNDERSTORMS ARE BEGINNING TO DEVELOP ALONG THIS FRONTAL ZONE
TOWARDS THE SOUTHEAST PART OF OUR CWA.

THIS AFTERNOON-EVENING...ALONG THIS FRONTAL ZONE ANALYSIS INDICATES
ML CAPE VALUES RANGING FROM 1500 J/KG IN THE WARM SECTOR TO 500
J/KG IN OUR SE CWA. BULK SHEER IS APPROXIMATELY 30-35KT...SO
DEPENDING ON POSITION OF FRONT (CURRENTLY ADVERTISED TO SLIDE NORTH
INTO OUR SOUTHEAST)...THERE IS THE POTENTIAL FOR A FEW STRONGER
THUNDERSTORMS...POSSIBLY SEVERE WITH LARGE HAIL/DAMAGING WINDS MAIN
THREAT. IF FRONT WERE TO LIFT NORTH AS WARM FRONT WE COULD SEE
BETTER SB/ML CAPE AND THE POSSIBILITY FOR A FEW MORE ORGANIZED CELLS
IN THE SOUTHEAST. ANALYSIS ALSO INDICATES PWAT VALUES ALREADY IN
EXCESS OF 1" OVER OUR EAST. STORM MOTIONS WILL BE ROUGHLY
TANGENTIAL/PARALLEL THIS AFTERNOON BECOMING PERPENDICULAR TO FRONTAL
ZONE THIS EVENING. AS THIS TRANSITION OCCURS THERE IS THE
FOR BACKBUILDING OR TRAINING AS VERY MOIST/UNSTABLE AIR IN THE WARM
SECTOR FEEDS NORTH. THERE COULD BE A THREAT FOR FLASH FLOODING IF
THIS SCENARIO PLAYS OUT. EITHER WAY WITH VERY MOIST AIR MASS AND
INCREASING ELEVATED INSTABILITY...THUNDERSTORMS COULD BE VERY
EFFICIENT RAINFALL PRODUCERS.

TONIGHT-TUESDAY...UPSTREAM AREAS OF MID LEVEL VORTICITY WILL ROTATE
INTO THE CWA WITH INCREASING LIFT LATE THIS EVENING INTO THE
OVERNIGHT. AS TROUGH CONTINUES TO DEEPEN OVER THE SW US AND MOVE
EAST WE WILL CONTINUE TO SEE VERY GOOD FORCING/MOISTURE ROTATES
THROUGH THE REGION. LARGE SCALE Q VECTOR FIELDS INDICATED FORCING
INCREASING THROUGH THE NIGHT AND  OMEGA/MOISTURE
CONVERGENCE FIELDS SHOW SUPPORT FOR INCREASING COVERAGE/COMPLEX OF
SHOWERS THUNDERSTORMS. ELEVATED INSTABILITY TRANSITIONS NORTHWARD
AND WEAKENS...HOWEVER THERE IS ENOUGH TO KEEP THUNDER MENTION IN
PLACE THROUGH TUESDAY AFTERNOON. WHILE GUIDANCE IS IN AGREEMENT ON
GENERAL LARGE SCALE PATTERN THE MAIN DIFFERENCES ARE ON TIMING OF
POTENTIAL PERIODS OF HEAVIER PRECIP...WITH BEST PRECIP SIGNAL AND
MOISTURE PROFILES OVERLAPPING TUESDAY MORNING THROUGH TUESDAY
AFTERNOON ACROSS THE WESTERN 2/3 OF THE CWA (THOUGH ECMWF MIGHT BE A
LITTLE EAST). THERE WILL BE MODERATE/ELEVATED INSTABILITY IN PLACE
THROUGH THE DAY TUESDAY...SO STRONG TO SEVERE THUNDERSTORMS WILL
STILL BE POSSIBLE AGAIN...THOUGH SEVERE POTENTIAL MIGHT NOT BE AS
GOOD AS TODAY WITH WIDESPREAD SHOWERS AND STRATUS LIMITING SURFACE
BASED PARCELS AND ANY ACTIVITY LIKELY EMBEDDED WITH OTHER SHOWER
CLUSTERS.

.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 227 AM MDT TUE MAY 5 2015

A HIGH AMPLITUDE TROUGH WITH A CLOSED LOW WILL AFFECT THE TRI STATE
AREA TO START THE LONG TERM FORECAST PERIOD FRIDAY...WHICH WILL
BRING INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS MUCH OF
THE FORECAST AREA FOR THE DURATION OF THE FORECAST PERIOD.
GFS/ECMWF/CANADIAN FORECASTS ALL INDICATE THE SLOW MOVING TROUGH
WILL AFFECT THE REGION FOR THE DURATION OF THE COMING WEEKEND.  THE
TROUGH TAKES A NEGATIVE TILT SATURDAY IN THE GFS/ECMWF
FORECASTS...WHICH WILL STEEPEN LAPSE RATES ALOFT AND INCREASE CAPE
VALUES.  A STRONGER JET MAY ALSO BE IN THE AREA TO HELP DESTABILIZE
THE ENVIRONMENT...BUT MODEL GUIDANCE DIFFERS AS TO THE ACTUAL
STRENGTH.  GFS FORECAST HAS AN UPPER LEVEL JET APPROACHING 80KTS
OVER THE FORECAST AREA...WHICH IS PLENTY STRONG TO GIVE 0-6 KM BULK
SHEAR VALUES APPROACHING 50 KTS.  LOWER LEVEL HODOGRAPHS ALSO HAVE
GOOD CURVATURE WITH 0-3 KM HELICITY APPROACHING CRITICAL VALUES FOR
TORNADOES. HOWEVER...ECMWF/CANADIAN MODELS ARE NOT AS ENTHUSIASTIC
AND HAVE BETTER JET LOCATED TO THE EAST OF OUR AREA.
THEREFORE...SEVERE THUNDERSTORM THREAT LOOKS TO BE POSSIBLE BUT NOT
DEFINITE AT THIS POINT.

HEAVY RAIN IS POSSIBLE SATURDAY NIGHT FOR MANY LOCATIONS DUE TO VERY
SATURATED MODEL SOUNDINGS AND CAPE IN THE PROFILE TO CONTINUE TO
DRIVE CONVECTION INTO THE EVENING. ALONG AN ADVANCING WARM
FRONT...AN MCS IS LIKELY TO DEVELOP AND BE PERSISTENT WITH THE
ENHANCEMENT OF THE LOWER NOCTURNAL JET. SHOWERS AND STORMS WILL
TAPER OFF TOWARDS SUNDAY MORNING.  SCATTERED THUNDERSTORMS MAY
CONTINUE INTO THE AFTERNOON HOURS WITH THE UPPER LEVEL TROUGH
LINGERING IN THE AREA...BUT THE BASE OF THE TROUGH WILL PASS OVER
THE HIGH PLAINS MONDAY AND WILL EFFECTIVELY END THE HIGHER
PRECIPITATION THREAT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1142 PM MDT MON MAY 4 2015

MVFR TO IFR CONDITIONS FORECAST FOR THE 6Z TAFS. EXPECT CONDITIONS
AT KMCK TO REMAIN UNCHANGED UNTIL CLOSE TO MID MORNING. MEANWHILE
AT KGLD CEILINGS HAVE FLUCTUATED FROM IFR TO VFR OVER THE PAST
HOUR OR SO. EXPECT IFR CEILING IN THE NEXT HOUR. FOR BOTH SITES CEILINGS
SHOULD INCREASE TO MVFR DURING THE LATE MORNING...THEN FALL TO IFR
AGAIN IN THE EARLY EVENING.

THE SHOWERS SHOULD REMAIN SOUTH OF KMCK FOR THE REST OF THE NIGHT
AND THROUGH MOST OF THE DAY. DURING THE LATE AFTERNOON THERE MAY
BE A SHORT WINDOW FOR STORMS TO MOVE NEAR THE SITE...BUT WILL
WAIT FOR LATER TAFS TO ADDRESS THIS.

KGLD SHOULD REMAIN RAIN FREE TONIGHT. DURING THE LATE MORNING AND
THROUGH THE AFTERNOON RAIN CHANCES WILL INCREASE...WITH THE BEST
CHANCES DURING THE MID TO LATE AFTERNOON. BY EARLY EVENING THE
CHANCES FOR RAIN WILL BEGIN TO DECLINE.

EXPECT VISIBILITY REDUCTION FOR BOTH SITES DURING THE
OVERNIGHT HOURS. VISIBILITY SHOULD IMPROVE DURING THE MID TO LATE
MORNING.


&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

UPDATE...JTL
SHORT TERM...DR
LONG TERM...MK
AVIATION...JTL


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