Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 250529
AFDGLD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
1129 PM MDT SUN AUG 24 2014

.UPDATE...
ISSUED AT 915 PM MDT SUN AUG 24 2014

HAVE JUST COMPLETED A FORECAST UPDATE FOR TONIGHT INTO TOMORROW.
INCREASED PRECIPITATION CHANCES DUE TO EXPECTED ELEVATED
CONVECTION TONIGHT INTO THE MORNING. LATEST HIGH RESOLUTION
GUIDANCE BROUGHT THE AXIS OF PRECIPITATION SLIGHTLY FURTHER SOUTH
SO MADE THE SAME ADJUSTMENT TO POPS AND QPF.

AS OF 9 PM MDT...SPC MESOANALYSIS INDICATED MUCAPE OF
1000-2000 J/KG TO THE WEST AND ON THE INCREASE OVER THE TRI-STATE
REGION...MID-LEVEL LAPSE RATES OF 7-8.5 C/KM AND INCREASING WIND
SHEAR AS A SPEED MAX MOVES INTO NORTHERN COLORADO. LATEST
SOUNDINGS INDICATE THAT MUCAPE SHOULD CONTINUE INCREASING ACROSS
OUR REGION...POSSIBLY REACHING 1000-1500 J/KG. A LOW LEVEL JET WAS
INCREASING IN INTENSITY...CURRENTLY OUT OF THE SOUTHEAST AT 25
KTS OR SO RIGHT NOW BUT EXPECTED TO REACH 30-40 KTS AROUND TO
AFTER MIDNIGHT. MODEL GUIDANCE SEEMS TO HAVE UNDERESTIMATED THE
STRENGTH OF THE JET AT THE PRESENT TIME. THUNDERSTORMS SHOULD
BEGIN TO DEVELOP WITHIN THE NEXT 1-3 HOURS AND SPREAD NORTHEAST
OVER THE REGION THROUGH THE MORNING HOURS. SOME ACTIVITY IS
ALREADY DEVELOPING OVER NORTHEAST COLORADO BUT ADDITIONAL
DEVELOPMENT OVER EAST COLORADO AND NORTHWEST KANSAS SHOULD BEGIN
SHORTLY. A FEW STORMS COULD BE STRONG TO SEVERE WITH LARGE HAIL
AS THE MAIN THREAT.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 1233 PM MDT SUN AUG 24 2014

UPPER LOW OVER THE NORTHERN HIGH PLAINS TODAY WILL LIFT NORTH INTO
CANADA WITH SOUTHWESTERLY FLOW ALOFT OVER THE CENTRAL HIGH PLAINS.
AT THE SURFACE...COLD FRONT HAS STALLED OUT ACROSS CENTRAL AND
SOUTHWEST KANSAS. SCATTERED THUNDERSTORMS IN EASTERN COLORADO THIS
AFTERNOON WILL BE SLOW TO MIGRATE EASTWARD THIS EVENING AND WILL
PROBABLY ONLY MAKE IT TO YUMA COUNTY. THE BIGGER CONCERN WILL BE
THUNDERSTORM CHANCES OVERNIGHT AS ISENTROPIC LIFT DEVELOPS ON THE
315K SURFACE ASSOCIATED WITH 30KT LLJ. PARCELS ORIGINATING AROUND
775MB WILL HAVE 1000-2000 J/KG OF ELEVATED CAPE WITH LITTLE CIN.
AS A RESULT...STORMS WILL BE CAPABLE OF PRODUCING LARGE HAIL. BEST
CHANCES WILL BE NORTH OF INTERSTATE 70. STORMS WILL PERSIST INTO
MONDAY MORNING IN NORTHEAST CORNER OF THE FORECAST AREA...FROM
MCCOOK TO NORTON...BEFORE EXITING TO THE NORTHEAST BY LATE
MORNING. THE AFTERNOON HOURS ON MONDAY WILL SEE ONLY SLIGHT
CHANCES FOR THUNDERSTORMS AS THE NEXT SHORTWAVE TROUGH WILL STILL
BE BACK IN COLORADO. TEMPERATURES TONIGHT AND MONDAY WILL BE NEAR
NORMAL.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 310 PM MDT SUN AUG 24 2014

PRIMARY FORECAST CONCERN WILL BE COVERAGE AND INTENSITY OF
THUNDERSTORMS FROM MONDAY NIGHT INTO WEDNESDAY. THIS WILL
DETERMINED BY WHERE INCOMING FRONT DECIDES TO BE. SATELLITE
SHOWING AN AMPLIFIED PATTERN FROM THE PACIFIC INTO THE WESTERN
ATLANTIC. UPPER SYSTEM OVER THE NORTH CENTRAL PORTION OF THE
COUNTRY IS MOVING SLOWLY NORTHEAST AS ANOTHER SYSTEM OVER WESTERN
CANADA DIVES INTO THE WESTERN PORTION OF THE COUNTRY.

AT JET LEVEL...THE GFS AND CANADIAN APPEAR TO START OUT THE BEST. AT
MID LEVELS...MODELS APPEAR A LITTLE FAST IN BRING IN NEW LOW INTO
THE NORTHWEST PORTION OF THE COUNTRY. AT THIS TIME IT LOOKS LIKE
THE GFS...CANADIAN AND ECMWF ARE DOING THE BEST. THE NAM WAS DOING
A LITTLE BETTER THAN THE ECMWF ON THE SURFACE WIND AND PRESSURE
FIELD. THE GFS AND ECMWF APPEAR TO BE DOING BETTER ON THE LOW LEVEL
THERMAL FIELD.

MONDAY NIGHT...RIGHT REAR QUADRANT OF JET APPEAR TO AFFECT THE
NORTHWEST HALF OF THE AREA THROUGH THE EVENING. SHORTWAVE TROUGH
EXPECTED TO MOVE ACROSS FROM SOUTHWEST TO NORTHEAST DURING THE
NIGHT. MODELS A LITTLE CLOSER IN THERE POSITION OF THE FRONT.
THE NAM DOES DEVIATE FROM THE OTHER GUIDANCE BY TAKING THE FRONT
FURTHER SOUTH DURING THE NIGHT WHILE OTHER OUTPUT DOES NOT CHANGE
THE POSITION MUCH. THAT MAY BE A RESULT OF THE COLD POOL GENERATED
BY THUNDERSTORMS NORTH OF THE FRONT.

SO WILL CONTINUE WITH HIGH CHANCE TO LIKELY POPS MONDAY NIGHT
WITH THE HIGHEST POPS IN THE NORTH. STORM MOTION WILL BE NEARLY
PERPENDICULAR TO THE FRONT WITH PWATS 1 TO 1.5 INCHES. SO WILL
EXPECT LOCALLY HEAVY RAINFALL WITH SOME SEVERE THUNDERSTORMS
INVOLVED.

TUESDAY/TUESDAY NIGHT...WEAK RIGHT REAR QUADRANT APPEARS TO AFFECT
THE NORTHERN AND WESTERN PORTIONS OF THE AREA DURING THE AFTERNOON
AND EVENING. NAM DOES BRING THE FRONT BACK NORTH DURING THE DAY
TO A POSITION NEAR TO JUST SOUTH OF ITS POSITION ON MONDAY. MODELS
NOW DO TAKE FRONT FURTHER SOUTH DURING THE NIGHT...ESPECIALLY THE
NAM. OTHERS KEEP IT A LITTLE FURTHER NORTH. CAN SEE WHERE THIS
MIGHT HAPPEN AND AM CONCERNED FRONT MAY BE GETTING TOO FAR SOUTH.

THERE IS STILL A DECENT SHORTWAVE TROUGH COMING THROUGH IN
SOUTHWEST FLOW ALOFT. MODELS DO GENERATE AND MOVE LIFT FROM SOUTH
TO NORTH DURING THE NIGHT. WILL KEEP THE POPS BUT NOT AS HIGH AS
THE PREVIOUS NIGHT DUE TO BOUNDARY POSITION UNCERTAINTY. WITH
STORM MOTIONS STILL PERPENDICULAR TO THE FRONT AND PWATS
INCREASING TO NEAR 1.5 TO ALMOST 2 INCHES...LOCALLY HEAVY RAINFALL
COULD BECOME EVEN MORE OF A THREAT.

KEPT HIGH TEMPERATURES NEAR OR BELOW THE COOLEST GUIDANCE SEEN.
MAXES ALMOST PROBLEMATIC AND WILL DEPEND ON HOW MUCH/FAST THE
CLOUD COVER WILL DEVELOP.

WEDNESDAY...MAIN JET LOOKS TO STAY WEST OF THE AREA. MEANDERING
FRONTAL BOUNDARY WILL BE NEAR OR OVER THE SOUTHERN END OF THE
FORECAST AREA. MODELS ARE NOW BRINGING A PRETTY STRONG SHORTWAVE
WITH SOME DIFFLUENCE IN ADVANCE OF THE INCOMING SYSTEM. SO RAISED
POPS FOR THE DAY TO HIGH CHANCE. WILL ALSO KEEP HIGHER POPS GOING
THROUGH THE WHOLE DAY SINCE MAY HAVE LINGERING IN THE MORNING PLUS
THE LIFT INCREASES DRAMATICALLY BY THE MIDDLE OF THE DAY DUE TO
THE PROXIMITY OF THE UPPER LOW.

THIS MAY BE THE BEST CHANCE FOR SEVERE THUNDERSTORMS DUE TO THE
STRENGTH OF THE LIFT. PWATS REMAIN CLOSE 1.5 INCHES WITH SLIGHTLY
SLOWER STORM MOTIONS WHICH WILL BE PERPENDICULAR TO THE FRONT.
LOCALLY HEAVY RAINFALL WILL ONCE AGAIN BE A BIG THREAT.

WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...EARLIER/OVERNIGHT
DETERMINISTIC/ENSEMBLE GUIDANCE STILL HAD A DECENT AMOUNT OF
SPREAD WITH THE INCOMING UPPER TROUGH. THEY ALL HOWEVER DID SLOW
UP THE ARRIVAL OF THE TROUGH. AT THAT TIME...THE GFS CONTINUED TO
BE THE OUTLIER WITH A MORE PROGRESSIVE AND WEAKER SOLUTION.

NOW THE LATEST GEFS AND 12Z GFS HAVE DRAMATICALLY REVERSED THEIR
PREVIOUS SOLUTIONS AND ARE MUCH SLOWER AND CUTOFF THAN BEFORE AND
IN SOME CASES ARE MORE CUTOFF AND SLOWER THAN THE ECMWF. THE NEW
GFS IS IN MUCH CLOSER AGREEMENT WITH THE LATEST ECMWF AND LOOKS
EVEN MORE LIKE THE NEW CANADIAN.

CONSIDERING THE CONSISTENT GUIDANCE...CURRENT PATTERN AND THESE
LATEST TRENDS...A SLOWER SOLUTION IS LOOKING MORE LIKELY AND
CONFIDENCE HAS INCREASED IN THIS SOLUTION. AS A RESULT THE NEW
CRH_INIT POPS ARE NOW HIGHER FOR WEDNESDAY NIGHT INTO THURSDAY
NIGHT WITH SLIGHT CHANCE POPS NOW INTRODUCED INTO FRIDAY AND
FRIDAY NIGHT. THIS IS A WHOLE DAY SLOWER IN ENDING PRECIPITATION
THAN YESTERDAY. IF THE GFS AND CANADIAN ARE RIGHT THE UPPER LOW IS
CUTOFF ALMOST ON TOP OF US.

IN THE WEDNESDAY NIGHT TO THURSDAY NIGHT TIME FRAME THE PWATS
REMAIN IN THE 1 TO 1.5 INCH RANGE. SO THE COOLER AND WETTER
SOLUTION LOOKS TO CONTINUE AND LIKE WHAT THE INIT POPS HAVE GIVEN
ME AND WILL NOT CHANGE.

SATURDAY NOW LOOKS LIKE THE DRY DAY. NEW DETERMINISTIC AND
ENSEMBLE DATA SUPPORT A FLATTER FLOW ON SUNDAY WITH A SHORTWAVE
TROUGH APPROACHING FROM THE WEST IN THE AFTERNOON ALONG WITH
HAVING A SURFACE TROUGH OVER THE FAR WEST PORTION OF MY AREA.
HOWEVER IF THE MODELS ARE CORRECT...700 MB TEMPERATURES ARE GOING
TO BE DRAMATICALLY WARMER AND POSSIBLY COULD CAP THE AIR MASS. THE
RUN OF THE INIT GAVE ME A SLIGHT CHANCE FOR SUNDAY AND FEEL
COMFORTABLE IN KEEPING IT AT THIS TIME.

ALSO DID NOT MAKE ANY CHANGES TO THE TEMPERATURES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1129 PM MDT SUN AUG 24 2014

ELEVATED THUNDERSTORMS HAVE DEVELOPED OVER EAST COLORADO.
ADDITIONAL ACTIVITY IS ANTICIPATED OVER THE REGION THIS MORNING.
STILL SOME UNCERTAINTY ON WHERE STORMS WILL DEVELOP/MOVE SO HAVE
KEPT VCTS IN TAF FOR KGLD. ALSO MAINTAINED TIMING FOR KMCK
ALTHOUGH SOME GUIDANCE SUGGESTS THERE MAY BE SOME SHOWERS
LINGERING THROUGH LATE MORNING. CONVECTIVE REDEVELOPMENT IS LIKELY
ONCE AGAIN BY AFTERNOON/EVENING. FOR NOW...PLACED VCTS TO
HIGHLIGHT THIS THREAT BUT WIDESPREAD CONVECTION SHOULD BE
EXPECTED. ONE LAST THING TO MENTION...SREF AND NAM ARE INDICATING
A CHANCE FOR STRATUS/FOG TOMORROW MORNING WITH A VERY MOIST
ATMOSPHERE. EARLY INDICATIONS ARE MVFR TO IFR CIGS/VIS ARE
POSSIBLE.

&&

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

$$

UPDATE...RRH
SHORT TERM...024
LONG TERM...BULLER
AVIATION...RRH


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