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Area Forecast Discussion (AFD)

Issued by Springfield, MO (SGF)

FXUS63 KSGF 190515

Area Forecast Discussion
National Weather Service Springfield MO
1115 PM CST Mon Feb 18 2019

.SHORT TERM...(This evening through Tuesday Night)
Issued at 315 PM CST Mon Feb 18 2019

Quiet to start with a dry Canadian sfc ridge extending from the 
northern Plains and Midwest south into eastern KS and MO. The
ridge will shift east of the region but sfc high pressure will
still remain in place north-northeast of the region with a dry 
low level fetch during the day Tuesday. 

A deep upper trough over the western CONUS will leave our region
in strong southwest flow aloft. A jet streak approaching from the
southwest along with lift in the right entrance region with
another jet max over the Midwest will produce deep lift coupled
with moisture advection increasing over the region. Guidance 
varies on details, but in general precip should spread northeast 
into the southern cwfa early/mid afternoon. Initially precip may 
start as a mix, but evaporative cooling into the dry air mass 
should turn most of the precip to snow by mid/late afternoon. Once
the lift overcomes the dry air, the initial precipitation may 
briefly be moderate to heavy with a quick couple of inches of wet 
snow for some.

Mid level dry air is expected to overspread the region Tuesday 
night. Cloud tops look too warm for the development of cloud ice 
(could be close though). Precip is expected to transition to light
rain or freezing rain (or drizzle). Sfc temperatures are expected
to be close to freezing for much of the night. Better chances for
freezing precip will be over the northern cwfa where some light 
ice accumulation will be possible. 

Given the snow and light ice accumulation, decide to go with a
winter weather advisory for Tue afternoon/night. It is very likely
that some areas, especially southern MO will not need the 
advisory for this entire period and we will certainly look at 
adjustments to the timing with forecast updates. 

Overall liquid rainfall amounts will be heaviest over our
southeast cwfa in south central MO once again. Right now, our
forecast has less than one inch of rain or liquid equivalent
everywhere, so we are not going with any hydro headlines. Wouldn't
be shocked that a low water crossing or two becomes flooded by 
Wed morning, but not expecting widespread issues. 

.LONG TERM...(Wednesday through Monday) 
Issued at 315 PM CST Mon Feb 18 2019

Main concern during this time will be the potential for heavy rain
and a few storms Saturday with strong sfc low pressure expected 
to move from the Plains through the lower MO River Valley. 

Wednesday-Friday: Looks quiet overall with a modest warming trend. 

Friday night-Saturday: Guidance has been consistent in ejecting a
strong shortwave from the Rockies to the Midwest (Cornbelt) by
Saturday night. Deepening sfc low pressure is expected to pass
near or just north of the cwfa. The ECMWF/GFS-FV3 are somewhat
farther north with the low track versus the GFS and Canadian 
GDPS. The low track will determine how far north instability 
makes it along with the potential of some stronger storms, but in 
either case some thunder will be possible. A period of moderate- 
heavy rain and some flooding may also be possible. Will continue 
to monitor trends for this period. 

Sunday-Monday: Sfc high pressure will briefly nose south into the
area during this time. Right now the forecast is dry. 


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1107 PM CST Mon Feb 18 2019

A deep upper system to our west will bring quite a bit of lifting
into the area on Tuesday as well as drawing Gulf moisture back
into the area. Ceilings will be on the decline as a significant
dry lower level will moisten up. Thermal profiles will be critical
as to precipitation type. Precipitation looks to move in by mid
afternoon. Looking at model comparisons of warm nose aloft, would
show precipitation starting out as snow and as temperatures warm
by mid to late evening, transitioning to a rain/snow mix before
mostly rain. Temperatures are forecast to be just above freezing,
so am not expecting much freezing rain. Flight conditions will be 
VFR until slightly after the precipitation starts and then tank
into IFR for much of the remainder of the TAF. Winds may become
quite gusty during the late afternoon into the evening hours with
some low level wind shear as well.


MO...Winter Weather Advisory from noon Tuesday to 6 AM CST Wednesday 
     for MOZ055>058-066>071-077>083-088>098-101>106.

KS...Winter Weather Advisory from noon Tuesday to 6 AM CST Wednesday 
     for KSZ073-097-101.