Area Forecast Discussion
Issued by NWS Topeka, KS

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000
FXUS63 KTOP 240849
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
349 AM CDT Sun Aug 24 2014

.SHORT TERM...(Today and Tonight)
Issued at 349 AM CDT SUN AUG 24 2014

Scattered high cloud continues to push NNE from central Texas
between the upper high centered over the Lower Mississippi Valley
and the strong upper low along the Wyoming/Montana border. Other more
isolated and slightly lower cloud making its way northeast across
north central Kansas nearly coincident with weak cold front from
north central Nebraska to southwest Kansas per 07Z objective
analysis. Low level jet of around 45kt at 500m AGL keeping winds
gusty over western half of the area and temps well into the 80s in
many locations.

Hard to rule out isolated very high-based showers in mainly western
areas through early afternoon where narrow layer of moisture around
650mb lingers, though at this point will leave chances of measurable
precip at less than 15. Greater concern for convection is for the
mid afternoon through overnight hours as the front continues
southeast, but still looks to hang up over our western counties this
afternoon, and recent 3-hr pressure change data of limited area of
rises behind the front supports this. Area of better moisture
convergence takes shape along and ahead of the front, but this
-better- amount is still limited. Have kept chances in the slight
range through the day with perhaps slightly better coverage this
evening into the overnight hours as the front stalls and any
outflows aid in additional development. High storm bases and limited
shear still suggest spotty downburst winds being the primary severe
weather concern. Temperatures and heat index values should again be
rather high despite somewhat more cloud cover in deep mixing.
Dewpoints look to be a few degrees above those of Saturday,
supported by upstream obs, with 100+ max apparent temps anticipated
for locations ahead of the front. Have only added Ottawa county to
the going Heat Advisory given a slight uptick in thermal fields in
central Kansas per all guidance. Have gone a bit above guidance for
lows tonight with similar low level jet developing but not quite to
this morning`s expected levels with the potential for evaporational
cooling from any precip.

.LONG TERM...(Monday through Saturday)
Issued at 349 AM CDT SUN AUG 24 2014

Shortwave trough moving along the BC coast and into the Pacific
Northwest early this morning will kick the Wyoming upper trough
northeast into southern Canada by Monday morning. This will push a
cold front south into the CWA and may likely bisect the area Monday.
The front is forecast to lift northward during the day on Monday and
move into Nebraska Monday night. The boundary will be a focus for
thunderstorms particularly in north central and northeast Kansas
near the Nebraska border. Expect temperatures to warm into the upper
90s south of the front and into the lower to middle 90s along the
northern border. Heat indices again reach into the 100-105 degree
range on Monday and will extend the heat advisory through 8 pm
Monday.

Models have been slowing the progression of the upper trough moving
across the Rockies from Wednesday through Friday. GEM/NAM/ECMWF
along with the GFS ensemble mean agree on the slower solution while
the operational 00Z GFS is faster moving the through while the
others slowly move the trough across the Plains Thursday through
Saturday. This will delay the cooler air arriving although outflow
from MCS moving across Nebraska will likely send an outflow boundary
south into the CWA and could also focus some thunderstorms.
Temperatures look to be cooler due to cloud debris and morning
precipitation on Wednesday while southern areas will remain very
warm. As a result of the slower progression of the upper trough and
front will keep precipitation chances into Friday.

&&

.AVIATION...(For the 06Z TAFs through 06Z Sunday Night)
Issued at 1143 PM CDT SAT AUG 23 2014

Vfr conditions are still expected to persist through the terminal
forecast period with only a few mid and sct-bkn high clouds
expected. Confidence in any elevated convection affecting any of
the terminal sites thru 12z or beyond 21Z remains too low to
insert into TAFS. Prevailing south winds will continue at speeds generally
under 10 kts before gradually increasing again aft 14z with a few
gusts near 20 kts.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY from Noon today to 8 PM CDT Monday FOR
KSZ010>012-021>024-026-034>040-054>056-058-059.

&&

$$

SHORT TERM...65
LONG TERM...53
AVIATION...63






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