Scientific Forecaster Discussion
fxus64 klzk 221123 aaa
Area forecast discussion...updated
National Weather Service Little Rock Arkansas
523 am CST Wed Nov 22 2017
Updated to include the 12z aviation discussion below...
VFR conditions should persist through this taf period. High
pressure will move over the state by this evening...with nearly
winds becoming light and variable.
Previous discussion...(issued 243 am CST Wed Nov 22 2017)
Short term...today through Thursday night
The cold front has pushed south through the state as of early this
morning...with mainly just dry air and a wind shift seen with this
front. This drier air will continue to filter into the state this
Wed as high pressure to the north moves south into the region. A
weak upper shortwave trough will drop southeast over portion of the state
this afternoon/evening...but moisture levels remain very low. As a
result...only some slightly increased cloud cover is expected with
this upper wave.
Surface high pressure will move over Arkansas tonight into the first half of
Thu...with light winds expected. Some increased clouds may again be
seen Thu morning with yet another weak upper disturbance moving
overhead. Dry conditions will persist through Thu night...with the
surface high shifting south of Arkansas. Weak srly surface flow will return...but
moisture levels will remain very low.
The lack of significant rainfall and with continued dry air moving
into the region will keep the wild fire threat at least elevated to
high across the state. Light winds over the coming days will help
limit some of this wild fire danger...but min relative humidity values will drop
below 40 percent for most areas...with some areas dropping below 30
percent. Some burn bans have returned...and with the lack of any
rainfall and continued dry airmasses moving into the area...the
number of burn bans may increase in the coming days.
Long term...Friday through Tuesday
The extended forecast will generally be dry with near normal
temperatures. Late in the period a frontal system may move through
the region, and possibly bring some chances of rain to AR, but
uncertainty does exist.
Friday will start with surface high pressure centered to the east of
Arkansas but still the main weather influence, while upper northwest flow
with little upstream short wave energy is seen. Friday night to
Saturday, a cold front and upper low pressure trough will move
through the region, but due to lack of moisture, only some clouds, a
wind shift to the northwest and cooler temperatures are forecast.
Surface high pressure and a cool and dry airmass filters into the
region. This holds over the region and Arkansas for the weekend.
A warming trend and continued dry weather conditions are seen Monday
and Tuesday, while the surface high pressure gradually moves east,
and a south wind flow returns to the region. Later Tuesday the next
cold front and upper system approach the region, and some rain
chances may be seen for Arkansas. There is uncertainty in the timing,
amount and location of convection at this time, and future model
runs will be needed to fine tune this precipitation chance.