Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 110118
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
818 PM EST Wed Dec 10 2014
...Brief light freeze and/or areas of frost possible tonight...
.Near Term [Through Tonight]...
The 7 pm EST regional surface analysis showed a ridge from the
Great Lakes to the central Gulf Coast, and a seasonably cool, dry
airmass across much of the eastern CONUS. Vapor imagery and upper
air data showed a split flow pattern, with a large cutoff low
centered over southern New England, and a ridge over the central
CONUS. High clouds were increasing upstream of our forecast area as
a weak short wave trough over TX approached. The only concern
with that feature is whether or not there will be a thick enough
cloud layer to limit cooling overnight, so we nudged the previous
low temperature forecast up a degree or two as a hedge. We still
expect a brief, light freeze at some of our normally coldest sites
(away from the beaches and cities). Areas of frost are likely as
well. Remember, frost can form even when the 6-foot temperature
(the level that official temperature observations are taken) are
above freezing; so very tender plants may need to be protected tonight.
[Through 00Z Friday] Conditions will be ideal for pilots through
at least Thursday evening. We expect no cigs below 25k ft,
unrestricted Vis, and light NW winds (less than 10 KT).
.Prev Discussion [327 PM EST]...
.Short Term [Thursday Through Friday Night]...
There will be little change in the weather through this period. High
pressure will remain centered well north of the area over the
Tennessee Valley. This will maintain a flow of dry cool air into the
region. Highs will be in the upper 50s on Friday and the lower 60s
on Saturday. Lows will be down around freezing both nights.
.Long Term [Saturday Through Wednesday]...
The CWA will begin the long term period in a fairly amplified and
progressive pattern. As an upper level trough over New England
begins to slowly move east Sunday night, the area will remain on
the southern side of 500-mb ridge. With weak flow aloft, and at the
surface, the air mass in place will slowly moderate ahead of our
next rain-maker on Tuesday.
An upper level trough currently off the Western CONUS will amplify
little as it moves eastward across the US. This should generate a
weak area of low pressure that will translate ENE across the Ohio
River Valley. A trailing cold front is expected to push through on
Tuesday and generate some showers. With instability lacking, and
dynamic forcing being relatively weak, do not expect much QPF, or
any severe weather. Behind the front temperatures will return to
near climatological levels.
High pressure will be centered well north of the area through much
of the period maintaining light to occasionally moderate northerly
winds through the weekend. The high will slide off to the east on
Monday as a frontal system approaches from the west. This will allow
winds to finally veer to onshore.
Relatively cool, dry conditions will continue into this weekend.
Daytime dispersion values will be rather low due to limited
vertical mixing and uniform winds in the boundary layer. RH
values may fall near locally critical values Friday afternoon, but
it`s unclear whether or not other factors will be in place for a
Fire Weather Watch.
With all rivers below action stage and no rain expected for the next
several days, there are no flooding concerns.
.Preliminary Point Temps/PoPs...
Tallahassee 33 59 32 63 32 / 0 0 0 0 0
Panama City 40 59 40 63 41 / 0 0 0 0 0
Dothan 34 57 34 61 36 / 0 0 0 0 0
Albany 31 58 31 62 33 / 0 0 0 0 0
Valdosta 32 58 31 61 32 / 0 0 0 0 0
Cross City 32 60 32 64 31 / 0 0 0 0 0
Apalachicola 39 59 38 62 39 / 0 0 0 0 0