Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Little Rock Arkansas
1156 PM CST Wednesday Mar 4 2015
snow continues to fall over north Arkansas. In central Arkansas...
sleet is mixing with snow. South Arkansas is seeing rain and
freezing rain. Central sections will change to all snow in the next
hour or two. The freezing rain will continue for several hours
before mixing with sleet and eventually turning to snow around
sunrise. Low ceilings and visibilities are expected through the
first part of the period...then clouds will break up from north to
south after sunrise. MVFR to IFR conditions are expected
early...then VFR for the latter half of the period.
Previous discussion... /issued 1010 PM CST Wednesday Mar 4 2015/
looking at the latest observations and radar trends...decided to
up snow amounts especially over the northeastern portions of the
County Warning Area.
Previous discussion... /issued 850 PM CST Wednesday Mar 4 2015/
winter storm continues to unfold pretty much as advertised and
minimal if any changes will be forth coming this evening. The
precipitation type has transitioned over to all snow roughly from
a Russellville to Clinton to Searcy and heading south.
Sleet has been common across central section with the changeover
to winter precipitation now just starting over the south where the
somewhat warmer air has been a little more stubborn to be scoured
out. Will continue all warnings until their scheduled expiration
types with radar continuing to show more precipitation to the west
and southwest of the state.
Still believe that after looking at the new models all precipitation
will transition over to snow for most of the state although will
likely be repressed over the south and southeast where the
transition will occur later.
Local storm report product has just been sent with snow amounts of
around 4 inches across the north and northeast with generally two
inches of sleet in central areas. These amounts still fall with
in range of the expected amounts.
Previous discussion... /issued 254 PM CST Wednesday Mar 4 2015/
Short term...tonight through Friday night
The main concern for the short term is the ongoing winter weather.
As such the discussion will focus primarily on that.
The forecast seems to be tracking decently this afternoon so no
significant changes have been made to the forecast accumulations
with the afternoon package.
A cold front stretched from northern Louisiana up through NE
Mississippi this afternoon...with Arctic air beginning to surge
south through Arkansas as of 2 PM. A wave of low pressure was
noted moving along the front from NE Louisiana into miss late this
morning. This contributed to keeping the cold air from spilling
around the Ozarks and down the Delta earlier today. However as
this has shifted to NE miss this afternoon...surface pressure analysis
has shown that the cold air has now begun to freely move south
through the eastern part of the state. All in all the freezing
line was about 2-3 hours later than forecast yesterday afternoon
or last night...but not too far off in the grand scheme of
things. As such still think the timing from the late morning
update is in good shape. Reports from social media show that sleet
is now beginning to filter as far south as Heber Springs in the
higher terrain...and to Batesville east of the Ozarks. A
changeover to all snow has already occurred in Harrison...Mountain
home...and areas further to the west like Bentonville and
fayetville. Given the trends...still expect to see freezing rain
and/or sleet to make it to the I-40 corridor around 5-6pm this
evening...with a change to all sleet or sleet/snow mix occurring
within a couple hours after that. Freezing rain and sleet should
make it to southern Arkansas around 8pm or so this evening. A
changeover to snow will occur through the night from north to
south...with snow making it to The Little Rock metropolitan area around
midnight and finally to southeast Arkansas around daybreak Thursday.
On radar...trends have shown a marked increase in precipitation
over the last hour or so...which will continue to be the case
through late tonight before precipitation begins to shift east of
the area during the early morning hours on Thursday. This lines up
well with the going forecast and current model data. Given the
trends in ptype reports coming in this afternoon as well as surface
observations...saw no reason to make any adjustments to the going
snow and ice accumulation forecasts. Still think that...between
the sleet and snow...areas around and to the north and east of
Searcy and Batesville will see somewhere around 4-6 inches total
accumulation. There could be some locally higher amounts but that
should be about right for most places in that part of the forecast
area. As you get back down towards the central part of the state
and areas like Russelville...Conway...Pine Bluff...and of course
The Little Rock metropolitan area...believe that the 2-4 inches is still
a good estimate there. Elsewhere in southern and southwestern
Arkansas...from Mena down to Arkadelphia and over to Monticello
for instance...snow and sleet accumulations will be in the 1-2
inch range most likely. However these areas could also pick up a
quarter of an inch of freezing rain before a change to sleet
occurs...so impacts will not necessarily be less than in the
northern parts of the state...just different.
Winds are also rather high this afternoon and expect this to
continue through the nighttime hours as well. Many sites have come
in with gusts between 25-35 miles per hour this afternoon. Thus utility
outages could become an issue...especially if significant icing
occurs before changing to sleet/snow. Will continue the lake Wind
Advisory as a result.
Long term...Saturday through Wednesday
Surface high pressure will be centered over the region with a broad
upper trough from central to eastern U.S. To start the extended
forecast. Weather conditions will be overall dry with temperatures
moderating over the weekend. Lows will be in the 20s to 30s...while
highs in the 40s to 50s. Models hint at some upper short wave energy
in the southern stream will a low chance of precipitation in the lower MS
valley. Due to uncertainty...have kept it dry at this point. Monday
to Wednesday...surface high pressure remains the main feature over
the region...with weak short wave energy moving through the lower MS
valley and much of the lift appears to stay south of Arkansas. Tuesday to
Wednesday may see a bit more short wave energy closer to
Arkansas...especially southern areas...and a slight chance of rain may be
possible. Have included that for Wednesday. Temperatures for the coming
week will be at or above normal values. Overall confidence in
forecast is moderate.
lake Wind Advisory until 6 am CST Thursday for Arkansas-Bradley-
Winter Storm Warning until 6 am CST Thursday for Arkansas-Baxter-