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-- Discussion containing changed information from previous version are highlighted. --
658
FXUS62 KTAE 030747 AAA
AFDTAE

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TALLAHASSEE FL
245 AM EST Sun Mar 3 2013


.NEAR TERM [Through Today]...
The large scale longwave pattern overnight remains highly amplified.
This is highlighted by full latitude ridging over Wrn half and
troughing over Ern half of Conus EWD into extreme Wrn Atlc with axis
from low near NYC SWWD well into gulf of Mex. Assocd shortwave
moving off Carolina coast. At surface, low off Canadian Maritimes
with series of reinforcing troughs pivoting SWWD down in Gulf. One
of these "spokes" was rotating across local region overnight
bringing another batch of arctic. Just upstream, strong high
pressure from the Hudson bay SWWD to Cntrl Gulf.

Pre-dawn satellite pix show thick area of stratocu moving SEWD
across local area but EWD shift of H85 moisture axis and mixing
created by the low level ascent has been able to begin to erode the
saturated layer, albeit slower than expected. Because of slower
erosion and winds staying in the 5 to 8 mph range, updated AFD
earlier to tweak up sunrise temps a few degrees. Even so, further
erosion should allow good radiational cooling to yield a cold start
of the day.

As trough moves ewd with axis offshore today, the large scale
pattern will deamplify some with some rising heights over Ern
states. Still with 12z Sun 1000-850mb thickness expected to range
from 1278 (SE AL) to 1284 meters (SE Big Bend), ample Cold Air
Advection (negating sunshine), and enough mixing for persistent nw
breezes, expect another very chilly day for the region. Expect
inland sunrise temps in low 30s most sites rising to only in
the Lower-Mid 50s. But winds will make it feel even colder to start
the day with wind chills from low 20s north to upper 20s south.

&&

.SHORT TERM [Tonight Through Tuesday]...
-- Changed Discussion --
Another cold night is expected tonight, and in fact we may see a
more widespread freeze with lower winds overall and less cloud
cover. The Freeze Watch will likely be upgraded to a Freeze Warning
later today.

The first couple days of the work week will feature a quick air
mass recovery from the cool, dry weather that we have experienced
this weekend. The latest model guidance is in good agreement that
a strong shortwave trough (currently arriving on the Washington
and British Columbia coast per water vapor loops) will develop
into a closed mid-upper level low over Montana tonight. The low
will then dig southeast to the Mid South by Tuesday evening.
Therefore, mid-upper level height rises should be quite pronounced
from tonight through Monday, with warming temperatures and return
flow. Both Monday and Tuesday should be warmer than the previous
day, with highs on Tuesday as warm as the mid-70s, which would be
our first temperatures that high in about a week.

We expect most of the rain associated with the digging upper level
low to hold off until Tuesday Night, as that is when most models
focus the strongest QG convergence and frontal passage. Some low
PoPs were maintained on Tuesday, though, as models indicate some
increasing isentropic ascent during the day in the 290-300K planes
with relatively high RH in the same layer. Therefore, we could see
some showers in the WAA regime as well as mostly cloudy skies, but
most of the rain should arrive after 00z Wednesday.
-- End Changed Discussion --

&&

.LONG TERM [Tuesday Night through Saturday]...
Outside of one more chance of showers and storms across the
region on Tuesday Night as a cold front passes through the CWA, a
fairly benign period is expected for much of the extended period
with slightly below climo temps. Although showers and storms are
expected with this cold front, the dynamics and especially the
thermodynamics do not appear to be robust enough to produce severe
weather at this time. However, this system will require some
monitoring, just in case it strengthens a bit more than expected.

&&

.AVIATION [through 06z Monday]...
Delayed clearing of stratocu a few hours at each site so 4-5k CIGS
will persist until around 12-14z. Otherwise, unlimited vis and cigs
are expected at all terminals thru next 24 hrs. NW winds will
continue to decrease to 5 to 10 KT into mid morning before
increasing to 12 to 17 KT, with occasional gusts to 20 KT. Winds
will decrease to light after sundown.

&&

.MARINE...
Offshore buoy observations indicate that marginal SCA conditions
are likely occurring in our two offshore zones - winds around 20
knots or so with seas around 7 feet. However, we have not really
seen much evidence of similar conditions in the nearshore zones.
The C-tower observation has shown adjusted 10m winds mainly in the
17-18 knot range, although a few stronger bursts have gotten close
to 20 knots. Just in case there is slight strengthening in the
winds before daybreak, we opted to keep the SCA going for the
entire marine area. Winds and seas will subside briefly tonight
and Monday, before increasing once more on Tuesday with the fast
approach of another cold front.

&&

.FIRE WEATHER...
Low relative humidities are expected both today and on Monday, plus
20 foot winds today and ERC both days will approach critical levels,
However, recent rains are keeping soils far too moist to support the
issuance of any red flag products at this time. The airmass will
noticeably moisten up during Tues as the next front approaches the
area. In wake of the front, the airmass will dry out again to
borderline red flag humidities Wed and Thurs.

&&

.HYDROLOGY...
Slow improvement continues to be noted along many of the rivers in
our area, although many of the lower portions of the rivers are
still in flood stage. Flows are on the decrease on the Chipola,
Ochlockonee, Choctawhatchee, and Flint Rivers, and on much of the
Withlacoochee River.

Early this morning, the vast majority of the river gauges appear
to be tracking extremely close to forecasts. One update that will
be made is to the Withlacoochee River point at Pinetta which has
risen slightly more than expected so far tonight. It appears to be
approaching a broad crest soon, but could continue to rise a
little bit more.

The primary focus for river flooding will shift to the Suwannee
River later this upcoming week. We should see at least minor flood
stages by Tuesday at Ellaville with the flood wave progressing
down river throughout the week. It is too early to rule out one or
more of the Suwannee River points reaching moderate flood stage.


---Points that have crested but are still in flood stage---

Choctawhatchee River at Caryville and Bruce
Chipola River at Marianna and Altha
Flint River at Bainbridge
Ochlockonee River near Concord and Havana
Apalachicola River at Blountstown
Withlacoochee River above Valdosta


Forecast confidence is average on eventual Suwannee River flood
levels in the minor to moderate category as the forecasts depend on
routed flow from the Withlacoochee and Alapaha Rivers which are
still in the process of cresting upstream from their respective
confluence with the Suwannee River.


---Forecasted Moderate Flood Crests---
Withlacoochee River near Pinetta

---Forecasted Minor Flood Crests---
Aucilla River at Lamont
Suwannee River at Ellaville and Dowling Park


For specific crest levels and timing of these crests, please
consult our AHPS page by clicking on Rivers and Lakes on our
website. This can be found at the following web address.

water.weather.gov/ahps2/index.php?wfo=tae

&&

.PRELIMINARY POINT TEMPS/POPS...
Tallahassee   54  28  65  43  74 /  0   0   0  10  20
Panama City   53  37  63  53  72 /  0   0   0  10  20
Dothan        52  32  64  49  72 /  0   0   0  10  30
Albany        52  29  64  43  72 /  0   0   0  10  30
Valdosta      53  28  64  40  72 /  0   0   0   0  10
Cross City    55  28  64  39  74 /  0   0   0   0  10
Apalachicola  53  35  59  52  70 /  0   0   0  10  20

&&

.TAE WATCHES/WARNINGS/ADVISORIES...

FL...FREEZE WATCH from late tonight through Monday morning for
     all zones.
     FREEZE WARNING until 9 AM EST /8 AM CST/ this morning for
     all zones.

GA...FREEZE WATCH from late tonight through Monday morning for
     all zones.
     FREEZE WARNING until 9 AM EST this morning for Baker-Ben Hill-
     all zones.

AL...FREEZE WATCH from late tonight through Monday morning for
     Coffee-Dale-Geneva-Henry-Houston.
     FREEZE WARNING until 8 AM CST this morning for Coffee-Dale-
     Geneva-Henry-Houston.

GM...SMALL CRAFT ADVISORY until 7 AM EST this morning for waters
     from Destin FL to Suwannee River out 20 NM.

     SMALL CRAFT ADVISORY until 10 AM EST this morning for waters
     from Destin FL to Suwannee River between 20 and 60 NM from
     the shore.

&&

$$

NEAR TERM...Block
SHORT TERM...Lamers
LONG TERM...Gould
AVIATION...Block
MARINE...Lamers
FIRE WEATHER...Block
HYDROLOGY...Lamers