Area Forecast Discussion Issued by NWS Topeka, KS
000
FXUS63 KTOP 161738
AFDTOP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1238 PM CDT SUN JUN 16 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM CDT SUN JUN 16 2013
AN UPPER LEVEL RIDGE WILL AMPLIFY ACROSS NM AND CO AND WILL KEEP
EASTERN KS IN NORTHWESTERLY FLOW ALOFT FOR TODAY AND TONIGHT.
A WEAK SURFACE FRONT EXTENDED ACROSS SOUTHEAST NE...SOUTHWEST INTO
NORTH CENTRAL...THEN BACK NORTHWEST INTO WESTERN NE. SEVERAL OUTFLOW
BOUNDARIES WERE NOTED ACROSS SOUTHWEST KS AND NORTHWEST OK.
TODAY AND TONIGHT...A LEE SURFACE LOW WILL DEEPEN ACROSS SOUTHWEST
KS THIS AFTERNOON. THE SOUTHERLY LOW-LEVEL FLOW WILL CONTINUE TO
ADVECT DEEPER GULF MOISTURE NORTHWARD ACROSS THE SOUTHERN AND
CENTRAL PLAINS. THE MODELS ARE HAVING A DIFFICULT TIME RESOLVING
SHORTER-WAVE LENGTH TROUGHS THAT MAY BE EMBEDDED IN THE NORTHWEST
FLOW ALOFT. THE 00Z NAM AND 12Z ECMWF MODELS DIG A MINOR H5 TROUGH
SOUTHEAST ACROSS SOUTH CENTRAL NE AND NORTHEAST KS THIS AFTERNOON.
THE STRONGER ASCENT AHEAD OF THIS UPPER WAVE IN COMBINATION WITH
SURFACE CONVERGENCE ALONG THE SURFACE FRONT ALONG THE KS AND NE
BORDER MAY CAUSE NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP AND
CONGEAL INTO A COMPLEX OF THUNDERSTORMS AFTER 21Z SUN...WHICH IS
FORECASTED TO MOVE SOUTHEAST ACROSS THE CWA PROVIDING HEAVY RAINFALL
AND THE POTENTIAL FOR STRONG TO DAMAGING WINDS AND SMALL HAIL TO
MUCH OF THE AREAS NORTH OF I-70...THEN A SECOND COMPLEX OF STORMS IS
FORECASTED TO FORM ACROSS WEST CENTRAL KS AND MOVE SOUTHEAST ACROSS
SOUTH CENTRAL KS DURING THE OVERNIGHT HOURS. THE NORTHERN EDGE OF
THIS SECOND COMPLEX MAY BRUSH THE SOUTHERN COUNTIES OF THE CWA
TONIGHT.
BOTH THE 00Z GFS MODEL AND 12Z GEM DO NOT SHOW A COMPLEX OF
THUNDERSTORMS DEVELOPING ACROSS NORTH CENTRAL KS...BUT DOES SHOW A
COMPLEX OF STORMS OR MCS DEVELOPING ACROSS WEST CENTRAL KS...WHICH
WILL MOVE SOUTHEAST ACROSS SOUTH CENTRAL KS THROUGH THE NIGHT.
THE MESOSCALE FORECAST MODELS...RAP...ARW AND NMM...ALL SHOW AN MCS
DEVELOPING ACROSS WESTERN KS LATE THIS AFTERNOON AND MOVING THIS MCS
SOUTHEAST ACROSS SOUTHWEST KS...NORTHERN OK AND SOUTH CENTRAL KS
THROUGH THE NIGHT. THE NORTHERN EDGE OF THE MCS LOOKS TO WEAKEN ONCE
IT MOVES INTO THE WESTERN COUNTIES OF THE CWA AFTER 6Z MON.
THERE ARE SO MANY MESOSCALE PROCESSES IN PLAY TODAY AND
TONIGHT...THAT I OPTED TO GO WITH CHANCE POPS FOR MUCH OF THE AREA
THIS AFTERNOON AND TONIGHT. I KEPT LIKELY POPS ACROSS THE EXTREME
SOUTHERN COUNTIES FOR TONIGHT IN CASE THIS AREA IS BRUSHED BY THE
NORTHERN EDGE OF THE MCS.
SEVERAL OF THE MODELS SHOW SBCAPE VALUES INCREASING TO 1500 TO 2500
J/KG RANGE THIS AFTERNOON AND THROUGH THE EARLY EVENING HOURS. THE
EFFECTIVE SHEAR VALUES WILL ONLY BE AROUND 20 KTS...THUS EXPECT
PULSE STORMS WITH THE PRIMARY HAZARD BEING QUARTER SIZE HAIL AND
ISOLATED DAMAGING WIND GUSTS. IF AN MCS DEVELOPS THIS AFTERNOON AND
TONIGHT THEN THERE MAY BE A WIDESPREAD DAMAGING WIND HAZARD ALONG
WITH HEAVY RAINFALL.
HIGHS TODAY WILL REACH THE MID TO UPPER 80S ACROSS MUCH OF THE AREA.
THE WESTERN COUNTIES MAY REACH INTO THE LOWER 90S. LOWS TONIGHT WILL
BE IN THE MID TO UPPER 60S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 344 AM CDT SUN JUN 16 2013
ONGOING MCS COULD STILL BE AFFECTING THE SOUTHEAST PORTIONS OF
THE COUNTY WARNING AREA MONDAY MORNING...BUT SHOULD BE EXITING THE
AREA BEFORE AFTERNOON. HAVE TRENDED THE POPS IN THIS DIRECTION WITH
A DRY FCST IN THE AFTERNOON FOLLOWING MORNING POPS AS HIGH AS 50
PERCENT SOUTH AND EAST OF I 35. MUCH DRIER AIR WILL ADVECT INTO
THE CWA MONDAY AFTERNOON AND NIGHT. WITH CLOUDS DECREASING FROM
WEST TO EAST THROUGH THE DAY...HIGHS MONDAY IN THE 80S LOOKS ON
TRACK...WITH READINGS BY SUNRISE TUESDAY SHOULD BE IN THE LOWER TO
MIDDLE 60S WITH THE AID OF MOSTLY CLEAR SKIES THROUGH MUCH OF THE
NIGHT. THE DRIER CONDITIONS WILL CONTINUE INTO TUESDAY AS THE AREA
IS TEMPORARILY UNDER WEST TO NORTHWEST FLOW ALOFT. HIGHS ON
TUESDAY WILL BE IN THE 80S AS WELL. AS THE WEST COAST UPPER LOW
BEGINS TO EDGE EASTWARD...A REAMPLIFICATION OF THE WESTERN RIDGE WILL
CREATE HIGH RISES THROUGH THE PLAINS RESULTING IN A TRANSITION
BACK TO WAA/MOISTURE ADVECTION. THIS WILL LIKELY RESULT IN MCS
DEVELOPMENT TUESDAY AND WEDNESDAYS NIGHTS TO THE WEST MOVING/DEVELOPING
EASTWARD INTO PORTIONS OF CENTRAL/EASTERN KS AS THE RIDGE BUILDS
AND TRANSITIONS BACK TO SOUTHWEST FLOW ALOFT BY THE END OF THE
WEEK. WILL KEEP POPS GOING FROM WEDNESDAY INTO THURSDAY NIGHT
BEFORE THE BUILDING RIDGE FOCUSES THE HIGHER PRECIP CHANCES
FURTHER NORTH OF THE CWA WITH WARMER AIR SPREADING BACK INTO THE
CWA. HIGHS FRIDAY AND SATURDAY LOOK TO BE IN THE 90S WITH LOWS IN
THE 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1235 PM CDT SUN JUN 16 2013
STILL NOT CERTAIN CONVECTION WILL DEVELOP AND MOVE OVER THE
INDIVIDUAL TAF SITES. AREA REMAINS RIPE FOR CONVECTION IF A WAVE
OR A BOUNDARY CAN MAKE IT INTO EASTERN KS AND WILL CONTINUE WITH
THE VCTS AT THIS TIME. MVFR CIGS SHOULD BREAK UP IN THE NEXT HOUR
OR SO WITH DAYTIME HEATING.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...67