Area Forecast Discussion
Issued by NWS Little Rock, AR

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FXUS64 KLZK 180157 AAB

Area Forecast Discussion...Update
National Weather Service Little Rock AR
900 PM CDT Sat Mar 17 2018


Overall forecast on track. Area of convection over northeast TX and
eastern OK moving east toward AR, but is expected to gradually
weaken due to limited moisture and decreasing lift. Short range
models also gradually weaken area as it moves east, while the best
chances for it to hold together will be over far southern AR south
to LA. Forecast has showers with isolated thunder. Surface analysis
has a weak boundary over southern AR, while a cold front sagging
into northern AR. The convection over southern AR will be focused
near and along the southern boundary. Otherwise, mostly cloudy skies
tonight with lows in the 40s north, to the 50s central and south.


.Prev Discussion.../ Issued 640 PM CDT Sat Mar 17 2018

Mainly VFR flight conditions will be seen over the next 24 hours.
Scattered convection may move into western to southern AR later
tonight, and patchy MVFR ceilings will be possible. A nearly
stationary front was over southern AR, and will be the focus for
most of the convection as an upper system moves through AR. Winds
will be west to northwest at 5 to 15 mph over most of AR, while
south of the boundary, a southwest wind less than 10 mph will be
seen. (59)


.Prev Discussion.../ Issued 317 PM CDT Sat Mar 17 2018/
.SHORT TERM...Today Through Monday

As of mid-afternoon, a quasi-stationary frontal boundary was
draped from near TXK northeastward to MEM. Relatively cooler temps
were noted north of this feature, temps in the 60s to mid-70s F,
with a 15 to 20 F dewpoint gradient across the state. Temps have
already breached 80 F in southeastern AR, so keeping max temps this
afternoon a few degrees above guidance.

Aloft, objective analysis shows ridging across the central CONUS,
which will continue to shift east through the remainder of today
into tomorrow. A significant vort lobe is progged to eject from
the large trough positioned across the western CONUS. As this
feature quickly moves across the Rockies Sunday, upper-level
divergence will overspread the area with embedded shortwave energy
augmenting synoptic lift. The best deep moisture will initially
reside to our south across LA, TX, and MS; but northward moisture
transport is expected as surface cyclogenesis commences in the lee
of the Rockies through the day Sunday. Broad isentropic forcing
along the frontal surface will keep chances of showers and some
thunder in play beginning before dawn, mainly in southwestern AR
where moisture, instability, and dynamic forcing will be
maximized, although instability looks to be meager at best.

The parent upper shortwave will finally push into northwestern AR
by Monday morning with the surface cyclone riding through nearly
underneath the upper feature. Showers will gradually diminish
west- to- east into Monday afternoon as drier air as a modest
frontal boundary -- more akin to a dryline -- sweeps through by
Monday evening. Skies will clear behind this boundary with
increasing NW winds between 10 to 15 kts sustained across the
southern two-thirds of the state. Gusts could be as high as 25
kts, so caution should be exercised on area waterways.

Concerning the severe thunderstorm potential Sunday...while
dynamic forcing will be impressive aloft, guidance continues
showing a weaker wind field in the lower levels and modest mid-
level lapse rates. Forecast trends also continue nudging the
quasi- stationary boundary farther south compared to previous
model runs and, while some degree of warm sector development
could occur across south/southeastern AR, the likelihood of
significant destabilization and surface-based convection still
appears low. Even elevated instability will be limited based on
the latest guidance, with significant capping concerns across much
of the warm sector. That said, better instability and less CIN
across northern LA continue supporting some chance of severe
weather with hail and wind as primary threats. Best guess as of
this afternoon is that we could see some marginally severe hail
with any convection that can develop north of the boundary. Should
this boundary end up farther north than current thinking suggests,
severe weather chances could increase across southern AR. Overall
confidence in appreciable severe risk remains low this afternoon.



.LONG TERM...Monday Night Through Saturday

Medium range models are in generally agreement this afternoon in the
synoptic scale but there are some differences of note in the finer
details. That being said, a middle of the road approach seems to be

Period initiates with broad cyclonic flow aloft with a deep upper
low sitting off the west coast. Pattern will usher some cooler air
into the region but even so, temperatures will still average fairly
close to normals for the latter half of March.

Aforementioned upper low morphs into an open trough with subsequent
downstream ridging moving into the central plains. A few embedded
weak waves in the mean flow may bring a few periods of clouds and
even a stray shower but overall the chances of precipitation are
minimal through Thursday and even then, only the north would likely
be impacted. Southerly flow returns with time and temperatures warm
in response.

Rain chances do increase Friday as a stronger wave passes to the
north of the state. GFS is stronger with this system versus the
ECMWF so higher pops justified here. Next system approaches the
state late in the period for additional precipitation chances.


Batesville AR     69  43  60  48 /   0   0  60  70
Camden AR         80  54  67  59 /   0  60  70  60
Harrison AR       62  38  62  48 /   0   0  80  70
Hot Springs AR    77  51  64  54 /   0  30  70  60
Little Rock   AR  76  49  64  53 /   0  20  60  60
Monticello AR     82  54  65  58 /   0  50  60  60
Mount Ida AR      76  52  66  54 /   0  30  70  60
Mountain Home AR  62  39  62  46 /   0   0  80  80
Newport AR        68  43  60  50 /   0   0  60  70
Pine Bluff AR     79  51  66  56 /   0  30  60  70
Russellville AR   71  47  62  51 /   0   0  70  60
Searcy AR         73  46  61  51 /   0   0  60  70
Stuttgart AR      76  50  64  55 /   0  20  60  70

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


Short Term...COOPER / Long Term...GOUDSWARD is the U.S. government's official web portal to all federal, state and local government web resources and services.