Area Forecast Discussion
Issued by NWS Springfield, MO
FXUS63 KSGF 300534
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1134 PM CST Thu Jan 29 2015
.SHORT TERM...(This Evening through Friday Night)
Issued at 135 PM CST THU JAN 29 2015
Rather expansive area of stratus has engulfed the area today.
Starting to see a raggedness of the back edge of this cloud deck,
along with a rising of the cloud bases. As a result, we should
start to see gradual clearing commence over the next few hours.
Model relative humidity fields are usually tough to trust, but
they do try to keep low clouds hanging around the eastern Ozarks
into tonight and given the cyclonic flow around the exiting storm
system to our east, it`s plausible for clouds to linger.
Given strong northwest winds, cold advection and cloud cover,
temperatures have been rather stagnant today. Little additional
change in temperature is expected this afternoon and once skies
clear tonight, temperatures will fall at a good clip as surface
high pressure moves overhead and relaxes our wind fields.
Quiet and seasonable conditions are expected Friday into Friday
night. Lead wave of our next storm system will approach late
Friday night and have continued low chances for rain or snow
(could see a few sleet pellets given evaporative cooling
.LONG TERM...(Saturday through Thursday)
Issued at 135 PM CST THU JAN 29 2015
An upper ridge will be over the western U.S. late this week
leaving the region in a northwest flow a loft pattern. An upper
level low will push into the southwestern U.S. as an upper level
trough pushes south through the northwest flow into the region
this weekend. The upper level low will push off to the south this
by early next week, but energy from the low will spread north and
combine with the upper level trough pushing to the south to
develop light precipitation across the region starting later
Saturday and ending from west to east by Sunday night. A dry air
mass will be in place across the area on Saturday and will take a
little time to saturate and the light precipitation will begin to
spread from west to east across the area Saturday afternoon into
the evening hours.
Models are in good agreement that the region will be
affected by the system, but they still differ on the exact track,
which could vary slightly to the north or south. The 12Z suite of
models have come in slightly farther north than the 00Z models
did. Again the track will bring light precipitation to the region,
the question is the low level temperature profile of the
atmosphere. Temperatures will warm into the low to middle 40s on
Saturday, so when the precipitation spreads in it will start as
all rain. As temperatures start to cool during the evening and
overnight hours snow may mix with the rain, and in some locations
may change over to all snow. There is still questions on where
this transition zone will setup, as just a degree or two could be
the difference from rain, rain/snow mix, to snow. Lows Saturday
night are only expected to cool to the middle 30s to near 32.
Temperatures will warm into the middle 30s to near 40 Sunday
afternoon. Also given the warmer temperatures of light, think
melting will occur when the snow falls. There will be enough lift
for snow to fall, but we are not expecting high rates. Therefore,
given all this did go with a 7:1 snow to liquid ratio in calculate
snow ratio Saturday night into Sunday morning, and with a 4:1
ratio Sunday afternoon.
The colder temperature will be north, with the warmest south, and
its possible mostly rain occurs farther south. Again just a degree
or two different could be all the difference from rain or snow.
The best potential for minor accumulations will be on the plateau
and areas north of I-44 and at this time will be most likely on
grassy and elevated surfaces. Again, if the track changes
slightly expectations will need to change a bit, so continue to
monitor the latest forecast for more details regarding this
A much colder air mass will spread into the region behind this
system. Lows will drop well into the teens Sunday night with
highs only warming into the middle 20s to lower 30s Monday. Warmer
conditions will then occur on Tuesday before another system tracks
through the region bringing another shot of colder air to the
area during the middle to end of next week.
.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1130 PM CST THU JAN 29 2015
VFR conditions are expected to prevail through Friday evening with
increasing high clouds. There was some concern that low clouds
could return to southern Missouri late tonight, but upstream
satellite trends now indicate that the low cloud threat is
diminishing. Winds will remain light through the period.