Area Forecast Discussion
Issued by NWS Goodland, KS

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000
FXUS63 KGLD 021957
AFDGLD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
157 PM MDT SAT MAY 2 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 157 PM MDT SAT MAY 2 2015

LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW WESTERLY ZONAL
FLOW IN PLACE FROM THE GREAT BASIN ACROSS THE CENTRAL ROCKIES INTO
THE MISSISSIPPI VALLEY WITH EMBEDDED H5/H7 SHORTWAVE TROUGHS MOVING
THROUGH THE MEAN FLOW. AT THE SURFACE LEE TROUGH HAS DEVELOPED ACROSS
EASTERN COLORADO WITH A MEAN SURFACE TROUGH FROM THE NE PANHANDLE
AND ALONG THE COLORADO BORDER. THUNDERSTORM ACTIVITY HAS ALREADY
DEVELOPED ALONG THE CHEYENNE RIDGE AND HIGHER TERRAIN IN COLORADO.

THIS AFTERNOON-TONIGHT...RAP ANALYSIS (WHICH IS IN LINE WITH EARLIER
NAM) SHOWS 2000 J/KG OF SB CAPE IN PLACE ALONG AND AHEAD OF THE
SURFACE TROUGH...CENTERED OVER OUR CWA. CINH APPEARS TO BE
WEAKENING...HOWEVER ONLY SOME SHALLOW CU HAVE FORMED SO FAR THIS
AFTERNOON. AS MID LEVEL VORTICITY ROTATES FROM THE CENTRAL ROCKIES
INTO EASTERN COLORADO I WOULD EXPECT DEVELOPMENT TO SPREAD EAST
WHICH IS IN LINE WITH SYNOPTIC SCALE GUIDANCE. HRRR/RAP BOTH
INDICATE ISOLATED ACTIVITY DEVELOPING ALONG AND EAST OF THE SURFACE
TROUGH OVER OUR CWA WITH ADDITIONAL ACTIVITY SPREADING IN FROM THE
WEST. BULK SHEER/HELICITY ARE NOT VERY IMPRESSIVE AT THIS POINT
WHERE BETTER INSTABILITY IS IN PLACE (WEST). MOISTURE PROFILES ARE
NOT PARTICULARLY IMPRESSIVE...AND THIS COULD LIMIT COVERAGE TO
ISOLATE/SCATTERED. BETTER PRECIP SIGNAL AND INSTABILITY ARE SHOW IN
IN THE LOWER SHEER ENVIRONMENT...WHERE PULSE TYPE THUNDERSTORMS
WOULD BE MORE LIKELY. STEEP MID LEVEL LAPSE RATES AND MODERATE
INSTABILITY COULD SUPPORT STRONGER UPDRAFTS/CORES...WITH LARGE
HAIL/SEVERE WINDS POSSIBLE. DCAPE VALUES 1000-1500 J/KG AND IN
HIGHER TD DEPRESSIONS (MAINLY WEST) DO RAISE A CONCERN FOR INCREASED
MICROBURST POTENTIAL WITH SOME OF THESE STORMS. IF ANY OF THIS
ACTIVITY WAS TO MOVE INTO THE EASTERN CWA IT COULD BECOME MORE
ORGANIZED WITH INCREASING SPEED SHEER (35KT BULK EFFECTIVE SHEER
AROUND 00Z). AS THE SUN SETS AND WE LOOSE DAYTIME HEATING ANY
LINGERING ACTIVITY SHOULD QUICKLY WEAKEN AS THERE IS ELEVATED CAPE
LATE AND ONLY A WEAK LLJ IN PLACE OVERNIGHT.

SUNDAY...ANOTHER VERY WARM DAY IS EXPECTED AS SURFACE TROUGH DEEPENS
A LITTLE OVER THE CWA AND WAA INCREASES OVER THE CWA. THIS IS IN
RESPONSE TO A STRONGER SHORTWAVE TROUGH MOVING INTO THE NORTHERN
PLAINS AND A COLD FRONT DROPPING SOUTH INTO NORTHERN NEBRASKA. HIGHS
SHOULD BE SIMILAR TO TODAY WITH MOST IN THE 80S...AND A FEW
LOCATIONS APPROACHING 90 (MAINLY MCCOOK/HILL CITY). SURFACE TROUGH
WILL SHIFT JUST A LITTLE BIT EAST AND LOW LEVEL MOISTURE RETURN
COULD BRING HIGHER TD VALUES INTO NORTH CENTRAL KS. NAM MAY BE A
LITTLE HIGH...BUT EITHER WAY THIS BETTER BL MOISTURE WILL SUPPORT
HIGHER CAPE VALUES IN THE AFTERNOON IN THE 2000-2500 J/KG RANGE.
SHEER MAY ALSO BE A LITTLE BIT BETTER WHERE GOOD INSTABILITY IS IN
PLACE THAN TODAY...SO THERE MAY BE A BIGGER THREAT FOR MORE
ORGANIZE THUNDERSTORM DEVELOPMENT IF ANYTHING IS TO DEVELOP IN
THE AFTERNOON. THUNDERSTORM ACTIVITY IS SHOWN TO INITIATE
PRIMARILY ALONG SURFACE TROUGH IN THE AFTERNOON. HOWEVER WITH
DRIER MOISTURE PROFILES AGAIN IN PLACE COVERAGE COULD BE LIMITED
AT LEAST UNTIL LATER WHEN BETTER LARGE SCALE FORCING/DEEPER
MOISTURE MOVINGS IN TO THE REGION FROM THE NORTHWEST.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 226 AM MDT SAT MAY 2 2015

THE LONG TERM FORECAST PERIODS BEGINS WITH AN UPPER LEVEL SHORTWAVE
TROUGH THAT TAKES A NEGATIVE TILT INTO THE HIGH PLAINS
REGION...WHICH WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS
TUESDAY.  ALTHOUGH A NEGATIVE TILT USUALLY SIGNIFIES STEEP LAPSE
RATES ALOFT...IN THIS CASE THE LAPSE RATES ARE NOT TOO IMPRESSIVE
WITH VERY LITTLE CAPE IN THE PROFILE. BETWEEN 200 AND 500 J/KG OF
CAPE IS PRESENT ACROSS THE AREA TUESDAY AFTERNOON AND EVENING...BUT
THAT IS ENOUGH WITH VERY SATURATED FORECAST SOUNDINGS TO PRODUCE
EFFICIENT RAINFALL.  STRONG SOUTHERLY FLOW THROUGHOUT THE ENTIRE
ATMOSPHERIC PROFILE WILL ADVECT MOIST GULF AIR INTO THE REGION WITH
PRECIPITABLE WATER AMOUNTS ACROSS THE AREA GREATER THAN ONE
INCH...WHICH IS IN THE 99TH PERCENTILE BASED ON CLIMATOLOGY.
THEREFORE...INCREASED POP AND QPF VALUES IN THE FORECAST FOR THIS
PERIOD WITH THE EXPECTATION OF WIDESPREAD MODERATE RAINFALL...WITH
LOCALLY HEAVY AMOUNTS.

IN THE EARLY MORNING HOURS WEDNESDAY...GFS SOUNDINGS INDICATE AN
INTRUSION OF DRY MID LEVEL AIR...WHICH WILL INCREASE CAPE VALUES IN
THE PROFILE HEADING INTO WEDNESDAY AFTERNOON BETWEEN 1000 AND 1800
J/KG....WHICH COULD RESULT IN SOME STRONGER THUNDERSTORMS.  SEVERE
POTENTIAL DOES NOT LOOK STRONG AT THIS POINT WITH WEAK SURFACE
FORCING...MARGINAL SPEED AND DIRECTIONAL SHEAR...AND DISAGREEMENT IN
MODEL FORECASTS REGARDING JET POSITION.

ALTHOUGH MODELS DISAGREE SLIGHTLY TO THE UPPER LEVEL TROUGH
POSITION...TIMING AND PATTERN GENERALLY LINE UP ON THURSDAY
AFTERNOON WITH THE UPPER TROUGH GETTING PINCHED OFF FROM THE MAIN
FLOW AND BECOMING CUT OFF OVER THE WESTERN THIRD OF THE CONUS.
BECAUSE THE LOW WILL BECOME REMOVED FROM THE MAIN UPPER JET
FLOW...THE FEATURE WILL SPIN SLOWLY EASTWARD OVER THE HIGH PLAINS
REGION PROVIDING CHANCES FOR SHOWERS AND THUNDERSTORMS THURSDAY
NIGHT THROUGH FRIDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1137 AM MDT SAT MAY 2 2015

VFR CONDITIONS AND WINDS LESS THAN 12KT SHOULD PREVAIL AT BOTH
KGLD AND KMCK TERMINALS THROUGH THE TAF PERIOD. PRIMARY AVIATION
CONCERN WILL BE POTENTIAL FOR ISOLATED TO SCATTERED THUNDERSTORMS
DEVELOPING ALONG SURFACE TROUGH THIS AFTERNOON AND EVENING. BETTER
COVERAGE SHOULD REMAIN ALONG COLORADO STATE LINE WITH
ACTIVITY TRANSITIONING EAST AND SOUTH BASED ON SHORT RANGE
GUIDANCE. THIS PLACES ACTIVITY WITHIN THE VICINITY OF KGLD...BUT
LIKELY SOUTH OF KMCK. POTENTIAL EXISTS FOR STRONG/SEVERE
THUNDERSTORMS WITH HAIL/STRONG WINDS WITH SOME OF THESE
STORMS...SO WILL NEED TO AMEND IF IT LOOKS LIKE ANY PARTICULAR
STORM WILL IMPACT A TERMINAL. COVERAGE/CONFIDENCE TOO LOW TO
INCLUDE MORE THAN VCTS AT KGLD AT THIS TIME.


&&

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

$$

SHORT TERM...DR
LONG TERM...MK
AVIATION...DR


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