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Area forecast discussion...updated 
National Weather Service Little Rock Arkansas
931 am CST Tuesday Mar 3 2015


Just a quick update to adjust hourly temperature forecasts for the
rest of today...and also to extend the dense fog advisory in time.

Many observations across the southern half of the state are still
reporting visibility of less than a mile and several of those are
showing 1/4 mile or less. Since there is no marked increase in
winds...nor surface temperatures...expected for the next few hours
to promote any significant mixing of the low level
atmosphere...these low visibilities should continue. As such went
ahead and extended the dense fog advisory for another couple
hours. By then even the modest surface heating that we are getting
should be enough to lift visibility above a mile in most spots.
With lack of significant warming and mixing...also adjusted the
hourly temperature forecasts for the day. Most guidance still
suggests the southern half of the well as elevated
areas in the north...should see highs in the upper 50s to possibly
low 60s. Not extremely confident that this will happen but there
are some signs that the guidance may be on to something...such as
the middle to upper 40s noted at Mena and Harrison. So just adjusted
the hourly trends to show a slower warm up and will monitor the
situation as the day wears on.


Previous discussion... /issued 539 am CST Tuesday Mar 3 2015/

IFR to low IFR conditions are expected through the period. Precipitation
will be intermittent...with the highest coverage in the north. It
will transition to a wintry mix late tonight/early Wednesday morning...
with -raplsn prevailing at hro and bpk just before 12z. Tafs
already out.

Previous discussion... /issued 443 am CST Tuesday Mar 3 2015/

Short through Wednesday night

Dense fog has been noted across much of southern Arkansas through
the overnight hours. As a result...a dense fog advisory is in effect
through 15z.

Went and cut back on probability of precipitation during the daytime hours on Tuesday...with
most models showing very little in moisture through the day today.
However the better chances for rainfall will be across northern and
northwest Arkansas. A warm day will be on tap with the return of
warm and moist southerly flow. High temperatures today will be in
the upper 50s and 60s statewide. Precipitation chances will ramp up
after 00z tonight...and especially after 06z. Cold front will enter
northwest Arkansas slightly before 06z.

Behind this strong cold front...temperatures will plummet quickly
Wednesday night and through the day on Wednesday. Most locations
will see their Wednesday high temperatures very close to midnight.
For temperatures Tuesday night and through Thursday...went with a
blend of the raw GFS and European model (ecmwf)...with a lean towards the European model (ecmwf).
The NAM appears to be the outlier with this system. With this strong
front and the forecast strong temperature gradient...did not feel
wise to use MOS guidance. This temperature curve resulted in
temperatures dropping below freezing slightly earlier than
previously advertised. Still...expecting transitions from rain to
wintry precipitation around 12z in northern Arkansas...shortly
after 18z central...and shortly before 00z across the southeast.

As far as model trends go...the 00z Tuesday NAM and GFS
models...showed temperatures aloft much slower to cool...resulting
in much more sleet than previously forecast. The 00z European model (ecmwf) did not
follow suit reinforced previous thinking...that after a brief period
of sleet...precipitation will transition to snow. With still some
disagreement in the models...did not want to have a knee jerk
reaction and fully commit to mostly sleet...especially across
portions of central Arkansas. Using a blend of European model (ecmwf) and GFS for
quantitative precipitation forecast...the resultant forecast has four to six inches of snow and
sleet across the north...with two to four across central
Arkansas...and one to three in the south. Southern
Arkansas...especially the southeast will likely see more freezing
rain and sleet...than snow. In portions of southeast Arkansas do
expect ice accumulations to exceed a quarter of an inch. As a
result of these totals...did issue a Winter Storm Warning for the
entire area beginning 12z Wednesday and continuing through 12z

Very cold temperatures will be seen overnight Wednesday...into
Thursday morning with strong winds forecast. These strong winds will
likely compound any problems due to icing with sporadic power
outages possible.

Long term...Thursday through Monday

At the beginning of the period...the front will be well south of the
region. There may be enough moisture left over in the far southeast
for a brief period of light snow early...but this should dissipate
as Arctic high pressure moves into the region during the day.

Cold temperatures will be seen on Thursday...with most areas staying
close to or even below freezing. Things should clear out by Thursday
night...with winds becoming light and variable. This should be the
coldest night...with widespread temperatures in the teens to maybe
upper single digits. If this pans out...this would mean at least
daily record lows for quite a few locations. It does appear that
there could be a few places that come within a few degrees of
all-time record lows for the month of March.

The airmass will moderate by Friday night and the high
shifts toward the eastern Seaboard. Remainder of the period looks to
be dry...with temperatures slowly warming. However...readings will
largely remain below seasonal averages.

as discussed in the long term portion...daily record lows on March
6th will likely be in jeopardy. Here/S a list of some...

Station record low 3/6
Mountain Home 9 1920
Brinkley 10 1899
Calico Rock 11 1978
Conway 11 1901
Hardy 12 1901
Newport 14 1901
Gilbert 16 1980
Mena 17 1899
Mount Ida 17 1920
Russellville 17 1901
Batesville Airport 18 1943
Monticello 18 1978
Stuttgart 18 1960
Booneville 19 1989
Little Rock 19 1899
Pine Bluff 19 1920
Arkadelphia 20 1943
Sheridan 20 1962
Camden 21 1899
Searcy 22 2014
North Little Rock 24 1989
Jacksonville 26 1966
Star City 26 2014

There will likely some locations that come within a few degrees of
all-time record lows for March. Those are listed below...

Station all-time March record low
Conway 9 03/03/1943
Brinkley 10 03/06/1899
Little Rock 11 03/03/1943
Monticello 11 03/03/1980
Pine Bluff 11 03/09/1932
Jacksonville 12 03/09/1996
North Little Rock 14 03/03/2014
Star ciy 16 03/03/1980

This severe cold outbreak...while certainly noteable...does not
appear to be as widespread...or as prolonged as the one at the
beginning of last March.


Preliminary point temps/pops...
Batesville Arkansas 56 40 40 15 / 30 70 90 60
Camden Arkansas 65 60 60 24 / 30 40 90 80
Harrison Arkansas 55 30 30 10 / 30 50 90 50
Hot Springs Arkansas 59 50 50 21 / 30 70 90 80
Little Rock Arkansas 62 49 49 20 / 30 70 90 70
Monticello Arkansas 66 61 61 23 / 30 30 90 80
Mount Ida Arkansas 60 48 48 20 / 30 70 90 70
Mountain Home Arkansas 56 32 32 11 / 30 50 90 50
Newport Arkansas 58 41 41 17 / 30 70 90 70
Pine Bluff Arkansas 64 56 56 21 / 30 50 90 80
Russellville Arkansas 55 43 43 16 / 30 60 90 60
Searcy Arkansas 58 45 45 18 / 30 80 90 60
Stuttgart Arkansas 60 49 49 20 / 30 70 100 70

Lzk watches/warnings/advisories...
Winter Storm Warning from 6 am Wednesday to 6 am CST Thursday
for Baxter-Boone-Cleburne-Fulton-Independence-Izard-Jackson-
Johnson-Marion-Newton-Pope-Searcy-sharp-stone-Van Buren.

Winter Storm Warning from noon Wednesday to 6 am CST Thursday
for Arkansas-Clark-Cleveland-Conway-Dallas-Faulkner-Garland-
Grant-Hot Spring-Jefferson-Lincoln-Logan-Lonoke-Monroe-

Dense fog advisory until 11 am CST this morning for Arkansas-
Hot Spring-Jefferson-Lincoln-Lonoke-Monroe-Montgomery-Ouachita-

Winter Storm Warning from 6 PM Wednesday to 6 am CST Thursday
for Bradley-Calhoun-Desha-Drew-Ouachita.




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