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fxus64 klzk 122315 aaa 
afdlzk

Area forecast discussion...updated
National Weather Service Little Rock Arkansas
515 PM CST Tue Dec 12 2017

Aviation...
VFR conditions are expected through the next 24 hours, with no
significant weather or obstructions to visibility. Surface ridge
will shift eastward through Wednesday, with southwest winds
developing and increasing to 10 to 15 knots sustained, with higher
gusts. Tafs out shortly.
&&

Previous discussion...(issued 259 PM CST Tue Dec 12 2017)
short term...tonight through Thursday
latest satellite imagery and surface observations indicate clear
conditions continuing across the mid south, with near normal
afternoon temperatures. The clear conditions will continue during
this period.

Of particular concern are expected fire weather conditions,
especially between 18z and 00z Wednesday. Fastest forecasts
indicate values approaching red flag criteria across the western
third of the forecast area during this time. After coordination
with neighboring offices, headlines have not been issued, but
this situation will need to be monitored closely.

Compressional flow will aid in warming conditions on Wednesday. A
quickly moving cold front will move south through the state
Wednesday night and will promote cooler than normal temperatures
for Thursday. No precipitation is expected with this feature.

Long term...Thursday night through Tuesday

Thursday night through Sunday...northwest flow aloft will persist
through Friday night inhibiting any attempt at moisture return to
the State of Arkansas. The persistent northwest flow pattern that
has been keeping US extremely dry here in Arkansas is expected to
change on Saturday as a large upper trough is forecast to dig south
over The Rockies towards New Mexico and West Texas. This large upper
trough will set up a short term upper air pattern that is much more
favorable for rainfall by bringing southwest flow aloft over the
state.

The consensus of the GFS and European model (ecmwf) is that shortwave troughs within
the southwesterly flow aloft will keep the low-level jet veered on
Saturday and Saturday night preventing a true "warm sector" from
setting up over Arkansas. However the change in flow regime is
expected to allow deeper moisture to return aloft which should lead
to a decent chance of rain across Arkansas as the stronger forcing
for ascent associated with the upper trough swings over the state.
At this time the consensus of model guidance is that this lift will
arrive over the state Saturday night through Sunday morning. As a
result have a 30 to 40 percent chance of rain in the forecast during
this time.

Because the best low-level moisture/Theta-E Pool is expected to
remain southeast of Arkansas...do not think that rainfall rates will
be heavy and should consist of rain shower activity instead of
thunderstorms. The limited access to better low-level Theta-E air
will limit rainfall rates likely keeping rainfall totals at less
than an inch across the state. It's not much rain, but at this rate,
we'll take what we can get! This system certainly does not look like
a drought buster, but any additional soil moisture is welcome with
much of the state mired in d2 and d3 drought conditions according to
the unlimited drought monitor.

Uncertainty regarding when the best lift will arrive this weekend
resulted in lower pops being spread out in the forecast through
Monday morning. It will likely not rain consistently from Saturday
night through Monday morning...and the forecast window of best rain
chances will be tightened up as confidence increases in the timing
of the lift in later forecasts.

Early next week...confidence in the forecast beyond this upcoming
weekend is somewhat low. There is a chance that another shortwave
trough will bring some light rainfall over the state Monday night
into Tuesday morning...but opted to leave rain out of the forecast
for now due to ongoing drought conditions across the state. There's
certainly nothing in the boundary layer or state of vegetation
across the state that's going to contribute as a source of moisture
early next week. As a result will continue to side with a dry
forecast at this time.
&&

Lzk watches/warnings/advisories...none.

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