Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 010437
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1137 PM CDT TUE JUN 30 2015

...UPDATE TO AVIATION FORECAST DISCUSSION...

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 258 PM CDT TUE JUN 30 2015

CURRENTLY, THE 19Z VISIBLE AND IR IMAGERY SHOWS THE MAJOR TROUGH
OVER THE EASTERN CONUS AND THE RIDGE AXIS OVER THE GREAT BASIN
EXTENDING UP INTO THE NORTHERN ROCKIES WITH NORTHWEST FLOW STILL IN
BETWEEN.  THE RIDGE IS CONTINUING TO FLATTEN AS A MINOR SHORTWAVE
CONTINUES TO WORK ITS WAY INTO THE NORTHERN GREAT PLAINS WHICH IS
SHOWING UP WELL ON WV IMAGERY.  A SURFACE LOW CAN BE SEEN AS THE
PREDOMINATE FEATURE OVER EXTREME SOUTHEASTERN MONTANA WITH A
STATIONARY BOUNDARY EXTENDING SOUTHEAST INTO NORTH CENTRAL NEBRASKA
AND PARTS OF SOUTHWESTERN IA.  THE SMOKE PLUME FROM WILD FIRES OVER
CANADA IS STILL WORKING INTO FAR NORTHEASTERN KS, BUT HAS NOW
ADVECTED MOSTLY INTO MID-MISSISSIPPI VALLEY.

WINDS WILL GRADUALLY SHIFT TO THE SOUTHEAST BY TONIGHT IN ADVANCE
OF THE SHORTWAVE PREVIOUSLY MENTIONED AS IT WORKS INTO THE CENTRAL
PLAINS. THIS SHOULD BRING A SMALL CHANCE OF PRECIPITATION TO THE
OUTLOOK AREA FOR EARLY TOMORROW MORNING AS AN AREA OF WEAK SURFACE
LOW PRESSURE OVER NORTHWESTERN KS AND SOUTHWEST NE DEVELOPS AND
SHIFTS EAST. THE BEST RAIN AND ISOLATED THUNDERSTORM CHANCES
SHOULD BE OVER EXTREME NORTH TO NORTHEASTERN KS AS THE BEST
ISENTROPIC LIFT DEVELOPS AND WEAK UPPER LEVEL FORCING WORKS OVER
THE REGION. THE BEST TIME FOR RAIN AND AN ISOLATED THUNDERSTORM
WILL LIKELY BE AROUND 10Z TO 15Z TIME FRAME PROVIDED ANY ACTIVITY
DEVELOPING LATER OVER EAST CENTRAL NE HOLDS TOGETHER AS MID TO
UPPER LEVEL HEIGHTS ARE CONTINUING TO BUILD OVER THE SOUTHERN
PLAINS INTO THE SOUTHERN CENTRAL PLAINS. THIS COULD ACT TO
SUPPRESS ANY ACTIVITY THAT DOES DEVELOP SOUTH AHEAD OF THE
ADVANCING SHORTWAVE.

TOMORROW SHOULD BE NICE IN THE AFTERNOON AFTER THE MORNING WAVE
MOVES THROUGH AND SKIES CLEAR AGAIN LATE MORNING.  TEMPS WILL LIKELY
RISE INTO THE LOW 90S.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 258 PM CDT TUE JUN 30 2015

WEDNESDAY NIGHT THROUGH FRIDAY...VARIOUS SHORT RANGE MODELS VARY
IN THE TIMING AND AMPLITUDE OF SHORTWAVE TROUGHS MOVING THROUGH
MID-AMERICA IN NORTHWEST FLOW ALOFT. IN GENERAL...BEST CHANCES
FOR PRECIPITATION WILL BE OVER FAR NORTHEAST/EASTERN KS WITH
BETTER LARGE SCALE LIFT...WHILE LESSER CHANCES EXPECTED FARTHER
WEST. THAT SAID...ANY MCS THAT GETS GOING IN WESTERN NEBRASKA
COULD AFFECT AREAS FARTHER WEST.

BEYOND THAT...CONSIDERABLE CHALLENGES EXIST IN TRYING TO TIME
BETTER CHANCES OF PRECIPITATION. FOR THE WEEKEND...ECMWF AND GEM
ARE REASONABLY CONSISTENT WITH EACH OTHER AND WOULD BRING BEST
CHANCES FOR THUNDERSTORMS SOUTH AND WEST OF AREA...WHILE GFS HAS
STRONGER FLOW ALOFT AND MORE PERSISTENT ISENTROPIC UPLIFT OVER
NORTHEAST KS WHICH WOULD INDICATE GREATER CHANCES THERE.

FOR EARLY NEXT WEEK...GFS AND ECMWF CONTINUE TO DIFFER IN
LONGITUDE OF UPPER RIDGE AXIS AS GFS KEEPS TRYING TO BUILD IT
EAST WHILE ECMWF WITH STRONGER NORTHERN STREAM WAVES SUPPRESSES
THE RIDGE. THUS...BOTH TEMPERATURES AND PRECIP CHANCES DIFFER
BETWEEN THE TWO MODELS. GFS ENSEMBLE HAS CONSIDERABLE VARIABILITY
DURING THAT TIME FRAME AND HAVE GONE WITH SOMETHING OF A
COMPROMISE AS A RESULT. HOWEVER...IF GFS TURNS OUT TO HAVE THE
BETTER HANDLE ON THIS PATTERN...FORECAST POPS FOR THE EARLY TO
MIDDLE PART OF THE WEEK MAY BE TOO HIGH AND FORECAST TEMPERATURES
TOO LOW.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1129 PM CDT TUE JUN 30 2015

SCATTERED SHOWERS WITH ISOLATED TSRA IS EXPECTED TO IMPACT
KTOP/KFOE THROUGH 12Z. ACTIVITY MAY BECOME MORE WIDESPREAD AFTER
09Z, HOWEVER UNCERTAINTY STILL EXISTS ON TSRA CLUSTER OVER NE
HOLDING TOGETHER TO IMPACT THE AREA SO WILL LEAVE IN VCTS. EAST
WINDS VEER TO THE SOUTH OVERNIGHT WITH THE FRONTAL BOUNDARY
SHIFTING WINDS TO THE NORTHEAST NEAR 23Z.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...DRAKE
LONG TERM...GDP
AVIATION...BOWEN


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