Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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000
FXUS63 KEAX 172310
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
610 PM CDT Mon Jul 17 2017

.Discussion...
Issued at 331 PM CDT MON JUL 17 2017

Heat remains the primary concern over the forecast period as the
upper-level ridge continues to expand and strengthen across the
eastern Plains. A few isolated thunderstorms are possible this
afternoon and early evening across central Missouri, where a
differential heating boundary set up on the edge of persistent
stratus; however, coverage will be limited and storms should be
brief if they develop. Afterward, the upper-level pattern will
steer disturbances well north of the CWA, and any cold-pool
propagation that takes storms southward to near the MO/IA border
would be so deviant from the forcing/support that it would likely
dissipate. As a result, convection is not expected to be a
limiting factor in the potential for dangerous heat indices except
across far northern MO where dissipating convection *could* limit
diurnal heating on any one of the upcoming days.

Surface high pressure currently over central and southern MO will
drift southeastward over the next several days, allowing return
flow to develop across the central and eventually eastern Plains.
Moisture will stream into the area but attempt to mix out during
the afternoons, resulting in lower to possibly mid 70s dewpoints
nearly every day. The (relatively) lowest dewpoints will occur
tomorrow before the best fetch of moisture develops out of the
Gulf, and when afternoon mixing may be efficient enough to knock
dewpoints back into the upper 60s during the afternoon. At the
same time, the 850 hPa thermal axis will slowly translate east and
southeast, positioning near the forecast area Wednesday through
Saturday. As a result, slightly warmer temperatures but similar
heat indices are expected tomorrow, with a bit more breeze to take
some of the edge off the uncomfortably muggy conditions; then,
dangerously hot temperatures and higher humidity will create heat
indices in the 105 to 110 range Wednesday through Saturday. Have
preemptively issued an excessive heat warning for that period of
time along and south of Highway 36, and have left the watch in
effect across our north where there is a higher (but still small)
chance for cloud cover to limit temperatures more than what is
currently shown in the grids.

The ridge may begin to break down on Sunday, but the shortwave
trough responsible is relatively weak and the overarching pattern
continues to look warm moving forward, so any relief that could be
in sight remains a bit blurry.

&&

.Aviation...(For the 00Z TAFS through 00Z Tuesday Evening)
Issued at 610 PM CDT MON JUL 17 2017

VFR conditions expected through the forecast. Diurnal CU currently
will dissipate soon after forecast issuance. Skies should then be
clear overnight with more diurnal clouds tomorrow afternoon. Winds
will be light through the evening/overnight hours then increase
some from the south tomorrow afternoon.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Excessive Heat Warning from noon Wednesday to 8 PM CDT Saturday
     for KSZ025-057-060-102>105.

MO...Excessive Heat Warning from noon Wednesday to 8 PM CDT Saturday
     for MOZ020>025-028>033-037>040-043>046-053-054.

     Excessive Heat Watch from Wednesday afternoon through Saturday
     evening for MOZ001>008-011>017.

&&

$$

Discussion...Laflin
Aviation...CDB



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