Area Forecast Discussion
Issued by NWS Springfield, MO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

000
FXUS63 KSGF 301107
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
607 AM CDT Thu Oct 30 2014

...12Z Aviation Update...

.SYNOPSIS...
Issued at 319 AM CDT THU OCT 30 2014

A large area of surface high pressure extended from the Great
Lakes into the Lower Mississippi Valley during the predawn hours.
This high resulted in another chilly night across the eastern
Ozarks with lows falling into the lower and middle 30s. Areas of
western Missouri and southeastern Kansas were 10-15 degrees warmer
as southerly winds increased behind that departing high. Skies
remained clear for most of the night with high clouds just
beginning to increase across central Missouri ahead of an
approaching short wave trough which was located across the Corn
Belt.

&&

.SHORT TERM...(Today and Tonight)
Issued at 319 AM CDT THU OCT 30 2014

That trough will dig southeast and pass across northern Missouri
this afternoon. Despite limited moisture with this trough,
models continue to indicate an impressive amount of lift ahead of
this wave. Good isentropic lift in the lower and mid levels of the
atmosphere will become juxtaposed with strong upper level lift
as our region becomes situated within the left exit region of an
upper level jet streak. Models also continue to advertise steep
mid-level lapse rates with the NAM indicating 200-300 J/kg of
MUCAPE. With at least marginal instability and plenty of lift
around, we have decided to include a mention of thunder.
Interestingly, increasingly cold mid levels along with initially
dry low levels may lead to graupel potential with some of the
"stronger" updrafts. Temperatures today will be somewhat tricky
given increasing clouds but rather warm 925/850 mb temperatures
ahead of that wave. We have gone fairly close to a MAV/MET blend
which puts most locations well into the 60s with a few low 70s
even possible back towards I-49. One other item to mention today
will be the passage of a cold front this afternoon as surface low
pressure tracks southeast into eastern Missouri. While cold air
advection will initially be lacking behind the front, a period of
brisk west and then northwest winds can be expected.

Any remaining showers will quickly end across the eastern Ozarks
this evening. We will see a period of clearing skies with
lighter northwest winds. A secondary upper level wave will then
quickly move southeast across the region late tonight. This will
lead to another increase in clouds. It is not out of the question
that we could see a patch of drizzle around...especially along the
Ozark Plateau. Meanwhile, northerly surface winds will begin to
increase late tonight resulting in increasing cold air advection.

.LONG TERM...(Friday through Wednesday)
Issued at 319 AM CDT THU OCT 30 2014

Friday then looks downright blustery as brisk northerly winds
continue to usher in a cold Canadian air mass. We should see
some morning cloud cover with an outside shot a patchy drizzle.
Skies should clear quickly but the sun will do very little to
overcome the cold air advection. We have continued the trend of
lowering expected highs on Friday as 850 mb temperatures plunge
below zero Celsius. Most areas will struggle to get out of the
middle 40s.

Surface high pressure will then nose down into the Missouri Ozarks
for Friday night which will set the stage for the end of the
growing season. Models have not backed off on the strength of the
high with a consensus somewhere in the 1032-1034 mb range. With
dew points expected to fall into the upper teens, overnight lows
are expected to fall into the middle 20s over most areas...with
lower 20s a distinct possibility in some locations. A few
locations may actually approach record lows Saturday morning. See
the Climate section below for more details. We have gone ahead and
upgraded the Freeze Watch to a Freeze Warning for this time period
given such high confidence in a hard freeze.

Temperatures on Saturday will then remain chilly with many areas
still not reaching the 50 degree mark. Areas out towards I-49
may get there if winds can come around to the southeast by
afternoon. Another frost or freeze will then be possible Saturday
night across the eastern Ozarks as a surface ridge axis is slow to
clear that region. It may not matter much by then given the high
confidence that the growing season will be over.

Sunday will then be a transition day as an upper level ridge
quickly moves east across the Ozarks. Temperatures will rebound
back into the 50s over all areas with southerly winds increasing.

That ridge will then quickly be replaced by southwesterly flow
aloft from Sunday night into Monday. Global models continue to
depict a positively tilted long wave trough setting up from the
northern Plains into the Desert Southwest early next week. Models
also continue to show a developing baroclinic zone from the
southern Great Lakes into the southern Plains. This spells a good
chance for rain and perhaps some thunderstorms from Monday into at
least Tuesday.

Where models are struggling is with the overall fate of that long
wave trough. Most models are showing the energy splitting with a
major piece dropping south into northern Mexico. The remaining
energy and an upper level trough axis are then forecast to slide
southeast into our region sometime in the later Tuesday or
Wednesday time period. The timing and structure of that trough
will be key in driving that baroclinic zone through our area and
eventually ending the threat for rain. If the 00 UTC ECMWF is
correct, the rain threat may not end until later Wednesday. On
the other hand, the GFS has the front clearing the area Tuesday
evening.

Temperatures during the early and middle portion of next week
should be fairly close to normal.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 601 AM CDT THU OCT 30 2014

VFR conditions are expected through the next 24 hours, though
winds will be a concern. A short period of LLWS is expected this
morning at JLN, before daytime mixing results in widespread gusty
southwest to west winds at all sites through the day today. Winds
will become northerly tonight behind a cold front, and while
speeds will not be as high as during the day today, a steady
breeze will continue. LLWS will then occur at all sites early
tomorrow morning. Some stratus will also be possible tomorrow
morning, though for now it appears that cloud bases will be high
enough to remain within VFR range.

&&

.CLIMATE...
Issued at 319 AM CDT THU OCT 30 2014

Record lows for November 1.

SITE...TEMP..YEAR

SGF...23...1991
JLN...22...1991
UNO...17...1993
VIH...21...1954

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FREEZE WARNING from 9 PM Friday to 10 AM CDT Saturday FOR
     MOZ055>058-066>071-077>083-088>098-101>106.

KS...FREEZE WARNING from 9 PM Friday to 10 AM CDT Saturday FOR KSZ073-
     097-101.

&&

$$

SYNOPSIS...Schaumann
SHORT TERM...Schaumann
LONG TERM...Schaumann
AVIATION...Boxell
CLIMATE...Boxell






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.