Area Forecast Discussion
Issued by NWS Springfield, MO

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000
FXUS63 KSGF 210554
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1154 PM CST Thu Nov 20 2014

.UPDATE...
Issued at 914 PM CST THU NOV 20 2014

The latest short term model guidance, 00Z RAOBs, surface observations,
and satellite imagery all indicate that patchy drizzle potential
will be slower to materialize tonight. Low level moisture is
currently having a tough time coming around the Boston Mountains
in northern Arkansas. Additionally, surface dew point depressions
remain high. The 00Z KSGF RAOB indicates a rather dry layer
below 850 mb. The KLZK RAOB indicates a bit more moisture in the
lower levels, but it is still rather dry below 925 mb.

With that being said, we have delayed the onset of patchy drizzle
until late tonight across southwestern Missouri. Any threat for
drizzle will likely hold off until Friday morning across central
Missouri.

With the delayed onset, the threat for freezing drizzle overnight
looks minimal at best given that areas of southwestern Missouri
will be above freezing late tonight. We will still have to watch
areas along and northeast of a Fort Scott, Kansas to Bolivar to
Willow Springs, Missouri line early Friday morning for patchy
freezing drizzle potential. Any threat for freezing drizzle will
end by 9 AM as temperatures warm above freezing area wide.

&&

.SHORT TERM...(This Evening through Friday)
Issued at 231 PM CST THU NOV 20 2014

After a cold start, temperatures have rebounded nicely over most
of the area. A good 25-30 degree diurnal swing has been observed
under a sunny sky. The surface ridge of high pressure is still
cutting across our eastern area, as a result temperatures should
drop quickly after sunset. Will need to watch the freezing line
carefully later tonight as shallow moisture returns to the area on
the heels of increasing southeasterly flow.

The short range models remain in good agreement for later tonight
into Friday. With a dry airmass in place at this time, concern for
widespread drizzle production is very low. That said, pockets of
patchy drizzle are still plausible after midnight and especially
as we get to daybreak Friday and thereafter. The freezing line
should begin to slowly retreat northward with time late tonight,
and accelerate north/northeast as we head into mid/late Friday
morning. At this point, the low risk for patchy freezing drizzle
will be from (roughly) a Fort Scott, KS to Marshfield and West
Plains in Missouri. If there is any patchy freezing drizzle that
materializes, accumulation will be little to none and confined to
bridges and elevated surfaces.

Friday into early Saturday will feature a period of gradually
warming temperatures. Limited moisture return will support patchy
drizzle and scattered showers, but certainly not expecting a wash
out. Enough instability will be around to support a slight chance
mention of thunder Friday night into Saturday.

By late Saturday into Saturday night, we will finally see deeper
moisture return to the area. Have maintained categorical PoPs and
continued the mention of slight chance for thunder. Temperatures
on Saturday will warm well into the 50s, with 60s by no means out
of the question.

.LONG TERM...(Friday Night through Thursday)
Issued at 231 PM CST THU NOV 20 2014

A vigorous wave will continue to move northeastward across the
Mississippi Valley into the Ohio River Valley on Sunday. A surface
low pressure will strengthen as it moves across Arkansas towards
Illinois. Sunday will be wet and expect breezy conditions late
Sunday into Monday with a strong pressure gradient. Another
shortwave will move across the Missouri Ozarks Sunday night to bring
additional showers before the whole system moves away from the area
early on Monday. Weekend rainfall totals will be between one and two
inches with the heaviest amounts south of I-44 across southern and
south central Missouri.

A deep trough will develop across the central U.S. for early next
week with a Canadian airmass over the region. This will bring below
average temperatures and drier conditions. With this forecast
update...Tuesday and Wednesday look fair and quiet across the region
for travelers. Highs will be in the 40s and lows at night in the
20s.

Even though Thanksgiving is just beyond this 7 day period
forecast...will mention that there is a lot of uncertainty between
the GFS and the ECMWF.  The ECMWF shows another Arctic blast and
some precip towards the end of next week while the GFS and GEM are
not indicating this. Just something on the horizon to keep an eye on.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1139 PM CST THU NOV 20 2014

Low level moisture will increase overnight and into Friday morning
ahead of an approaching upper level disturbance. Confidence
remains high that MVFR ceilings will develop Friday morning.
Patchy drizzle also remains possible from Friday morning into the
early afternoon. Weather models then continue to show lowering
ceilings throughout the day and into Friday evening. IFR ceilings
appear likely starting either late Friday afternoon or early
Friday evening. Scattered showers are also expected along with the
threat for isolated thunderstorms. We elected not to include
thunderstorms in the TAFs given the expected limited coverage.
Meanwhile, southeast surface winds will increase on Friday and
will be gusty from mid morning into the afternoon. Low level wind
shear will then develop by Friday evening as a low level jet
stream develops over southern Missouri.

&&

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

$$

UPDATE...Schaumann
SHORT TERM...Gagan
LONG TERM...Griffin
AVIATION...Schaumann




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