• Black Lake, Georgia, United States
  • WxZone: GAZ127ICAO: KABYLat: 31.57NLon: 83.89W
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335 PM EST Wed Feb 8 2012

.SYNOPSIS...Split flow pattern is in place over the western U.S. 
with a ridge over the Pacific Northwest and an anomalous upper low 
over the Baja.  The flow merges over the Southeastern states with a 
140kt jet associated with a shortwave pushing off the Eastern 
Seaboard. At the surface, cold high pressure is centered over 
Nebraska with a dry cold front moving through the local forecast 
area. As of 20Z, the front was situated along a line from St. Simons 
Island to Apalachicola. A dry airmass is pushing in behind the front 
with dewpoints in the 30s.

&&

.NEAR TERM [through Tonight]...A somewhat cooler and dry night is
on tap across the area in the wake of the cold front. Low
temperatures should drop into the upper 30s for most inland areas
by sunrise. Lingering high clouds and light northerly winds will
keep temperatures from dropping much further.

&&

.SHORT TERM [Thursday through Friday Night]...The trajectory of
the center of the surface high pressure looks to be from near
Missouri around 12z Thursday to offshore of North Carolina by 18z
Friday. This will leave our forecast area with a more peripheral
shot of cooler, drier air in the Short Term period. 850mb temps
for Thursday and Thursday Night look to be about +4C to +7C based
on SREF and GFS Ensemble means. This should result in highs in the
60s and lows in the upper 30s. For Friday, there is some more
uncertainty related to upstream phasing (or lack thereof) of
several mid-upper level shortwave troughs. At issue is the
interaction of a subtle shortwave in the process of amplifying
over Idaho at the moment, and an upper-level closed low near Baja
California. The 08.12z ECMWF takes the northern stream wave and
shifts it quickly ESE towards our area on the southern end of a
broadly amplifying trough in the eastern US, with the Baja closed
low spinning well away around 20N/110W. Meanwhile, the 08.12z GFS
phases the two waves in the Desert Southwest or northern Mexico as
an elongated trough. The recent runs of the UKMET and GEM look
similar to the ECMWF, and that is the direction the forecast
trends in. With the closed low near Baja California drifting south
on all the models, it does not seem likely that there will be much
interaction with a very progressive, low-amplitude wave far to the
north. The end result is that there is likely to be a bit more QG
convergence and broader mechanisms for ascent, which translates
into a cloudier forecast for Friday and Friday Night with some low
rain chances. The ECMWF QG convergence in the 700-300mb layer is
actually quite strong around 06z Saturday over our forecast area,
but there are some questions as to how fast a fairly deep layer of
mid-level dry air can be eroded. Therefore, the previous forecast
of slight chance PoPs was maintained for now.

&&

.LONG TERM [Saturday through next Wednesday]...The complex and
generally messy large scale pattern is expected to remain so
during the forecast period, while undergoing some retrogression,
with axis of the mean ridge over the western U.S. shifting
westward into the eastern Pacific, and the large polar vortex over
eastern Canada also evolving westward. The main effect will be to
broaden the mean trough westward across the CONUS, resulting in a
positive tilted trough axis across the Intermountain West, and a
nearly zonal flow eastward across the eastern half of the country.
The southern portion of the stream will remain quite strong. A
series of short waves will drop southward into the mean trough
axis over the Intermountain West, then weaken as they head rapidly
east or northeast across the eastern U.S. As always, the devil is
in the details when it comes to the forecast for he Tri-State
Area. The GFS and Euro continue to diverge predictably towards the
end of the period, in how they handle the short waves dropping
into the mean trough position. The Canadian and EURO are in better
agreement, showing more short wave energy in the southern stream,
which gives me some confidence, and a blend of the two solutions
seems the way to go. Friday night and Saturday short wave energy
will be moving eastward across the eastern U.S. pushing a cold
front well to the south across the southern Florida peninsula,
bringing at least a slight chance of rain, and a surge of colder
drier air behind it across the southeast U.S. Temperatures may
drop to near or a little below freezing in some areas on Monday
morning. Then expect a fairly rapid rebound in temperatures by mid
week, along with an increasing chance of rain, as the next short
wave rounds the bottom of the trough and heads NE. Temperatures
will start out near normal on Saturday, then drop below normal
Sunday and Monday, then trend back to above normal by Wednesday.

&&

.AVIATION [through 18z Thursday]...Overall, VFR conditions are
expected at all terminals through the forecast period. The only
uncertainty lies in the potential for smoke, from numerous
prescribed burn across the region, to impact visibility once the
sun goes down. At this time, expect winds to remain elevated
enough to keep boundary layer mixed, and prevent significant
restrictions due to smoke.

&&

.MARINE...The SCEC headline that was inserted earlier was kept
with the 4pm CWF issuance. We held off on a Small Craft Advisory
for now given the reluctance of statistical guidance to show 20kt
winds, and with high-resolution models generally peaking right at
20-21kt. We will likely be close to advisory criteria offshore
tonight, and the subsequent shift will monitor if a SC.Y becomes
necessary later this evening. Winds should drop off quickly on
Thursday, with another surge in winds expected this weekend as
colder air arrives.

&&

.FIRE WEATHER...A dry airmass will flood into the region for the 
next few days in the wake of a cold front. Minimum humidity values 
for Thursday are expected to reach the mid to upper 20s across 
Georgia and the Florida Big Bend, with lower 30s expected along the 
coast, the Eastern Florida Panhandle, and southeast Alabama. With 
ERC values currently below critical levels, no Red Flag Warnings are 
necessary at this time. Low level moisture will begin to return on 
Friday with minimum humidity values in the lower to mid 30s.

&&

.PRELIMINARY POINT TEMPS/POPS...
Tallahassee   39  66  37  70  41 /   0   0   0  10  20 
Panama City   45  64  44  65  49 /   0   0   0  10  20 
Dothan        38  61  37  66  41 /   0   0   0  10  20 
Albany        37  63  35  67  40 /   0   0   0  10  10 
Valdosta      37  65  38  69  43 /   0   0   0  10  20 
Cross City    38  69  40  72  45 /   0   0  10  10  20 
Apalachicola  45  64  45  65  51 /   0   0   0  10  20 

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.

&&

$$

Synopsis/Near Term...Camp
Short Term...Lamers
Long Term...Duval
Aviation...Camp
Marine...Lamers
Fire Weather...Camp
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