Scientific Forecaster Discussion
fxus64 klzk 232332
Area forecast discussion
National Weather Service Little Rock Arkansas
632 PM CDT Mon Oct 23 2017
main impacts this taf cycle will be frontal passage at central/southern
terminals this evening and gusty northwest winds for much of the day
Tuesday. No significant changes in forecast thinking with the
front expected to clear the area by 24/05z. In its wake, winds
have already or will veer northwest to north-northwest.
By Tuesday, a tightening pressure gradient will promote gusty
northwest winds at all terminals with sustained 15-20 kts and peak gusts
approaching or briefly exceeding 30 kts. VFR flight category
prevails the entire period.
Previous discussion...(issued 243 PM CDT Mon Oct 23 2017)
short term...tonight through Wednesday
A few high clouds drifting in from the northwest across the state
this afternoon while the upper low that helped bring storms to the
area this weekend was making its way northeast across the Ohio
River valley. Northwest flow aloft is in place over the state and
a dry cold front will make its way across the state this evening
through the overnight hours.
Pressure gradient will be amplified behind the front, especially on
Tuesday with a strong surface low expected to move toward the Great
Lakes area and high pressure settling in over much of the west and
into the Southern Plains. Expect northwest winds of 20-25 mph with
higher gusts, especially during the afternoon Tuesday.
With deep troughing aloft and surface high pressure shifting closer
to the area, much colder air will be seen for the day Tuesday and
especially Tuesday night. Daytime highs may not climb out of the 50s
in northern Arkansas without the aid of cloud cover or precipitation
which is fairly impressive. As the wind lessens Tuesday night and
high pressure slides closer to the state, one of the coldest nights
of the season will be seen as lows dip down into the 30s for a good
portion of the state. Some patchy frost will be seen.
Northwesterly flow aloft and dry/cool air will continue for
Wednesday. Surface high pressure will be centered southwest of the
area, providing westerly winds, still a bit strong at times.
Long term...Wednesday night through Monday
Quite a few changes will be taking place during the extended term,
namely with temperatures.
The term will begin with a return southerly surface flow in place,
with another cold front approaching the area from the northwest. The
return flow will not have much time to get established prior to the
arrival of the next front, and consequently low level moisture
levels will not increase all that much, with dewpoints only climbing
up into the mid 40s.
An associated upper level trof will also move into the area with the
front. The models are showing quite a bit of differences on the
timing of the front right now, with the GFS and Canadian models
bringing the front into Arkansas late Thursday night, with the European model (ecmwf)
a bit slower.
With surface moisture levels on the dry side, I have continued the
trend of keeping pops rather low, with the highest values of 30-40
pct across the southeast on Friday.
Of note will be the cold air moving in behind this frontal boundary.
By Saturday morning, the coldest temperatures of the season are
likely to be seen at many locations, with freezing temperatures
likely impacting much of the northwest half of the state.
lake Wind Advisory from 11 am to 7 PM CDT Tuesday for Arkansas-
Lake Wind Advisory until 7 PM CDT this evening for Baxter-Boone-