Area Forecast Discussion
Issued by NWS Springfield, MO

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000
FXUS63 KSGF 290826
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
326 AM CDT Wed Oct 29 2014

...End to the Growing Season Increasingly Likely this Weekend...

.SHORT TERM...(Today and Tonight)
Issued at 316 AM CDT WED OCT 29 2014

As of 3 AM...a large area of surface high pressure was situated
from  southern Nebraska into northern Oklahoma. Clear skies and
light winds prevailed across the region with early morning
temperatures ranging from the upper 30s to the middle 40s. There
is likely some patchy frost out there in protected valleys.

That high pressure will slowly slide southeast today resulting in
sunny skies and light winds. High temperatures will range from
near 60 degrees around Lake of the Ozarks to the upper 60s over far
southwestern Missouri. These temperatures are just a few degrees
below normal for this time of year.

The axis of that high will then slide slowly southeast across the
Missouri Ozarks tonight. Our confidence has increased in patchy
frost potential overnight across the eastern Ozarks given light
winds and expected low temperatures in the mid 30s. We will still
have to watch for late night increasing clouds as an upper level
disturbance approaches from the northwest. Meanwhile, areas back
towards I-49 will see slightly warmer temperatures as light
southerly winds kick in behind that ridge axis. Thus, there are no
frost concerns at this time across western Missouri and
southeastern Kansas.

.LONG TERM...(Thursday through Tuesday)
Issued at 316 AM CDT WED OCT 29 2014

That upper level disturbance will dig southeast across
northeastern Missouri during the day on Thursday. Moisture will
be very limited with this disturbance. What will not be limited is
lift. The digging nature of this system along with our area
becoming positioned within the left exit region of an upper
level jet streak will really boost mid/upper level lift.
Additionally, strong isentropic upglide will be present in the mid
levels along with marginal amounts of instability. We therefore
expect isolated to widely scattered shower activity with the
greatest potential for showers along and east of the U.S. 65
corridor. If the NAM is correct in advertising 200-300 J/kg of
MUCAPE, we could even see a rogue lightning strike or two. We have
opted against a mention of thunder for now but will pass this
concern onto future shifts.

That passing upper level disturbance will also have a surface cold
front associated with it. The air mass behind this front will
mean business as models bring a 1036-1038 mb surface high into
North Dakota Thursday night. Strong cold air advection will ramp
up across our neck of the woods from later Thursday night through
Friday as that surface high slides into the western Great Lakes
and Corn Belt. Friday looks downright blustery with brisk north
winds and increasing confidence that temperatures may not warm out
of the 40s.

While we are still several days out, almost all models are
painting a nearly perfect setup for an end to the growing season
Friday night. A surface ridge axis is forecast to extend from the
Great Lakes right through the heart of the Missouri Ozarks by 12
UTC on Saturday. With the parent surface high still progged to be
in the 1032-1034 mb range, temperatures should easily fall into
the 20s. We have lowered expected lows Friday night into the
middle 20s nearly area wide...which is very close to the 00 UTC
MEX numbers. If models continue to support this trend, a Freeze
Watch and eventual Freeze Warning almost seem inevitable.

Saturday will then be a chilly day across the region with highs
once again struggling to reach the 50 degree mark. We could then
see another frost or freeze Saturday night across the eastern
Ozarks depending on the position of that surface ridge axis. An
upper level ridge axis will then slide east across the region on
Sunday resulting in a dry day and temperatures rebounding into the
50s.

That ridge will be quick to move east of the area by Monday with
upper level southwesterly flow overspreading the region. Global
models continue to depict a positively tilted long wave trough
initially setting up from the northern Plains into the Desert
Southwest Monday and Tuesday. As this happens, models strengthen a
baroclinic zone from the Ohio Valley into the southern Plains.
Given the positive tilt of the trough, it is quite possible that
this baroclinic zone is slow to clear the area. We are therefore
looking at the potential for widespread precipitation for at least
a couple of days early next week...if not even longer.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1144 PM CDT TUE OCT 28 2014

VFR conditions are expected for the next 24 hours and beyond.
Surface high pressure will dominate our weather regime resulting
in a clear sky and light/variable winds.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

SHORT TERM...Schaumann
LONG TERM...Schaumann
AVIATION...Gagan





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