Area Forecast Discussion
Issued by NWS Little Rock, AR

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148
FXUS64 KLZK 241119 AAA
AFDLZK

Area Forecast Discussion...UPDATED
National Weather Service Little Rock AR
619 AM CDT Sun Sep 24 2017

.AVIATION...
With the exception of some patchy MVFR fog at Arkadelphia and
maybe Pine Bluff, VFR conditions are expected to prevail through
the period. Winds will be southeasterly at less than ten knots
during the day, becoming light and variable at night. Tafs out
shortly.
&&

.PREV DISCUSSION...(ISSUED 358 AM CDT Sun Sep 24 2017)
SHORT TERM...Today Through Monday Night
Same song, second verse. Rinse, repeat. Same stuff, different day.
No matter how I put it, there really are no big changes to the
going forecast. Sheesh, you`d think we were in the middle of
summer.

Anyway, analysis shows a closed upper low in the vicinity of the
Florida Panhandle region this morning. At the surface, a front is
currently stalled out in the high plains, with high pressure
covering much of the lower Mississippi Valley. The high will keep
any large-scale convection suppressed over the next two days.
However, with the upper low in place, we can`t rule out any
isolated showers/storms as daytime heating interacts with any
mesoscale boundaries and weak energy associated with the low.

High humidity near the surface, lack of clouds, and light winds
have allowed patchy fog to form in some river valleys and outlying
areas, and this should scatter out after sunrise as the gradient
increases. Given the same setup, wouldn`t be surprised to see this
again tomorrow morning.

And, of course, my favorite part (can you sense the sarcasm?)...
temperatures will remain above climatological averages. But, that
won`t last much longer.

LONG TERM...Tuesday Through Saturday
Synoptically, the persistent western trof/eastern ridge pattern will
finally break down as upper flow regime splits during the first half
of the week. Upper low ejecting northeast into central Canada will
help drag a cold front through mid week, although lack of moisture
will keep precip chances low and relegated to W/NW AR. That said,
still expecting a significant change of airmass in the front`s wake.
Upper ridging will be quick to build in/near the central Gulf with
initially zonal flow aloft by the latter half of the week.
Current GFS/ECMWF guidance remains in general agreement with the
south central U.S. on the northern periphery of the upper ridge
with progressive flow to our north. H850 temps will range from the
low teens north to mid teens south, so cooler temps overall with
afternoon highs in the 70s and 80s post-front. Overnight lows will
dip into the 40s to 50s with the slightly cooler temps mainly
across the north. Will also have to monitor increasing fire
danger. Please see Fire Weather discussion below for more details.

Generally good agreement among models, so used equal weighting for
GFS/ECMWF guidance and blended the result into a more general blend
of models. That said, did prefer drier solutions with frontal
precip, so utilized the GFS less for PoP grids.

FIRE WEATHER...
Through mid-week, there will be no significant fire weather
issues. A cold front will move through on Wednesday. After
frontal passage, a much drier air mass will push in with dewpoints
in the 40s and 50s area wide, along with increasing
north/northeasterly winds. Continued drying of vegetation is also
expected with much of the state running below 50 percent of normal
for precipitation so far this month. Fire danger will continue to
increase, especially during the Wed through Sat time frame. &&

.LZK Watches/Warnings/Advisories...NONE.
&&

$$


Aviation...57



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