Area Forecast Discussion
Issued by NWS Goodland, KS

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000
FXUS63 KGLD 030820
AFDGLD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
220 AM MDT SUN MAY 3 2015

.UPDATE...
ISSUED AT 814 PM MDT SAT MAY 2 2015

BASED ON RADAR TRENDS OVER THE LAST COUPLE HOURS AND LATEST MODEL
DATA...HAVE LOWERED RAINFALL CHANCES ACROSS MOST OF THE AREA
EXCEPT FOR THE YUMA COUNTY AREA AND GREELEY AND WICHITA COUNTIES
WHERE RAINFALL IS OR WILL BE MOVING OVER IN THE NEXT FEW HOURS.

LATEST DATA INDICATES THE LIFT OVER THE NORTHWEST QUADRANT OF THE
IS AT ITS BEST NOW AND WILL DECLINE RATHER QUICKLY OVER THE NEXT
COUPLE OF HOURS. FURTHER SOUTH...THE TRACK OF THE 700MB SHORT
WAVE TROUGH HAS BEEN PUSHED FURTHER SOUTH FOR TONIGHT...WITH THE
MAJORITY OF THE LIFT REMAINING SOUTH OF THE AREA. STILL EXPECTING
RAINFALL CHANCES TO END BY OR SHORTLY AFTER MIDNIGHT AS THE LIFT
WITH THE SHORT WAVE TROUGH COMES TO AN END AS THE TROUGH
FILLS/MOVES OUT OF THE AREA.

UPDATE ISSUED AT 552 PM MDT SAT MAY 2 2015

MAIN CHANGE WAS TO INCREASE RAINFALL CHANCES FOR THE EVENING BASED
ON LATEST DATA. LATEST RADAR SHOWS LINE OF STORMS AHEAD OF A 700MB
SHORT WAVE TROUGH OVER EASTERN COLORADO.  700-500MB FRONTOGENESIS
STRENGTHENS RAPIDLY DURING THE EARLY EVENING AND SHIFTS EAST TO
THE CENTRAL PART OF THE AREA BY MID EVENING ACCOMPANYING THE 700MB
SHORT WAVE TROUGH. MEANWHILE ISENTROPIC LIFT STRENGTHENS
THROUGH THE FIRST HALF OF THE EVENING...WITH THE STRONGEST LIFT
WEST OF HIGHWAY 25 WHILE CONDENSATION PRESSURE DEFICITS DECLINE.
TOWARD MIDNIGHT THE LIFT DECLINES AND CONDENSATION PRESSURE
DEFICITS INCREASE AS THE SHORT WAVE TROUGH MOVES ACROSS THE EAST
HALF OF THE AREA.

WITH THIS IN MIND HAVE THE HIGHEST CHANCES FOR RAINFALL DURING THE
FIRST HALF OF THE EVENING MAINLY FOR LOCATIONS SOUTH OF I-70.
TOWARD MIDNIGHT...AS ENVIRONMENT BECOMES LESS FAVORABLE FOR
RAINFALL...HAVE RAINFALL CHANCES QUICKLY DECLINING OVER THE EAST
HALF OF THE AREA.

LOOKING AT THE SEVERE WEATHER POTENTIAL...STRONGEST STORMS STILL
REMAIN WEST OF THE AREA WHERE THE BEST FORCING IS LOCATED. HAVE
HAD SOME ISOLATED STORMS DEVELOP ALONG THE SURFACE TROUGH
EXTENDING FROM SOUTHWEST TO NORTHEAST OVER THE CENTRAL PART OF THE
AREA. HOWEVER THESE STORMS HAVE BEEN TOO FAR REMOVED FROM THE
BETTER UPPER LEVEL FORCING TO LAST VERY LONG AND HAVE BEEN FAIRLY
WEAK. AS STORMS MOVE EAST INTO THE AREA...THE LIKELIHOOD FOR
SEVERE OUTFLOW WINDS INCREASES OVER THE NEXT HOUR OR SO BEFORE THE
INVERSION DEVELOPS. OVERALL SEVERE STORMS ARE MOST LIKELY WEST OF
HIGHWAY 25 PRIOR TO 9 PM CT OR 8 PM MT. AFTER THAT THE
FORCING...SHEAR...AND INSTABILITY DECLINE.

&&

.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...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 219 AM MDT SUN MAY 3 2015

THERE WILL BE CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE TRI
STATE AREA ON WEDNESDAY AS AN UPPER LEVEL SHORTWAVE TROUGH MOVES
ACROSS THE AREA. THE NEGATIVELY TILTED FEATURE WILL BRING SOME
STEEPER LAPSE RATES ALOFT AND AREA CAPE VALUES AROUND 1000 J/KG
WEDNESDAY AFTERNOON BASED ON GFS MODEL SOUNDINGS...HOWEVER WEAK
SPEED AND DIRECTIONAL SHEAR DOES NOT SUPPORT THE DEVELOPMENT OF
STRONGER STORMS. WITH SOUTHERLY ADVECTION THROUGH MOST OF THE
PROFILE WEDNESDAY MORNING...DEEP SATURATION IS LIKELY WITH
PRECIPITABLE WATER VALUES BETWEEN 0.80 AND 1.00 INCHES.
THEREFORE...RAIN SHOWERS AND GENERAL WIDESPREAD THUNDERSTORMS ARE
EXPECTED WEDNESDAY AFTERNOON AND EVENING WITH LOCALLY HEAVY RAINFALL
POSSIBLE.

THE UPPER LEVEL TROUGH CONTINUES TO DEEPEN OVERNIGHT WEDNESDAY AND
BECOMES SEPARATED FROM THE UPPER LEVEL FLOW THURSDAY OVER THE
WESTERN CONUS.  MODELS DIFFER SLIGHTLY ON THE PROGRESSION OF THE
PATTERN...BUT THE TIMING IS GENERALLY IN AGREEMENT FOR THE FEATURE
TO CONTINUE TO SPIN SLOWLY EASTWARD FOR THURSDAY THROUGH THE
BEGINNING OF NEXT WEEKEND...THUS AFFECTING THE TRI STATE AREA.
BECAUSE OF THE POSITION OF THE SLOW MOVING UPPER LEVEL
SYSTEM...THERE WILL BE CHANCES FOR SHOWERS AND THUNDERSTORMS FOR THE
ENTIRETY OF THE EXTENDED FORECAST.

SURFACE TEMPERATURES THROUGH THE PERIOD WILL REMAIN STEADY DUE TO
THE RELATIVELY UNCHANGING UPPER FLOW...WITH HIGHS IN THE MID TO
UPPER 70S AND LOWS IN THE UPPER 40S TO LOWER 50S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1055 PM MDT SAT MAY 2 2015

VFR CONDITIONS FORECAST FOR THE 6Z TAFS.  STORM ACTIVITY HAS COME TO
AN END ACROSS THE TRI-STATE AREA.  LIGHT WINDS WILL CONTINUE THROUGH
THE REST OF THE NIGHT AND SUNDAY.  DURING THE DAY A SURFACE TROUGH
WILL MOVE THROUGH THE AREA CAUSING THE WINDS TO TURN CLOCKWISE
THROUGH THE DAY...BECOMING NORTHEAST TO EAST BY EARLY EVENING.
DURING THE EVENING STORM COVERAGE WILL INCREASE.  DID NOT PLACE A
MENTION IN THE TAFS AT THIS TIME SINCE THERE IS A POSSIBILITY THE
STORMS WILL NOT MOVE NEAR THE SITES UNTIL AFTER 6Z...WHEN CHANCES
FOR STORMS WILL INCREASE.


&&

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

$$

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



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