Area Forecast Discussion
Issued by NWS Atlanta, GA
FXUS62 KFFC 201935
Area Forecast Discussion
National Weather Service Peachtree City GA
335 PM EDT Thu Oct 20 2016
.SHORT TERM /Tonight through Friday Night/...
Most significant feature noted in the regional water vapor loop
this afternoon is a strong shortwave over E Kansas/SW Missouri. At
the sfc...low pressure is located across W Kentucky...with
associated cold front draped SW from W Tennessee to W Mississippi.
Numerous showers and thunderstorms exist IN Vicinity OF this
Front should approach the NW corner of Georgia around 00z tonight.
This feature will give us our best chance for rain for the
foreseeable future. SPC mesoanalysis reveals an absence of
instability ahead of the front across our area...with Bufr soundings
showing a strong capping inversion in place across most of the
state. However...slightly cooler mid level temps/stronger H5 height
falls amidst rather strong diurnal heating across northwest Ga could
allow perhaps close to 1000J/KG MLCAPE to nose in before the sun
sets. This would support thunder...although severe potential remains
low as the best upper level support...shear...lapse rates remain
well displaced well behind the frontal boundary. It`s not completely
out of the question an updraft could support a gusty wind
threat...as mid level flow is strong enough to support short-lived
Front will slide SE across the CWA overnight tonight...with thunder
potential shutting off very quickly after sunset. With shortwave and
associated sfc wave remaining north of the area...the front will
lose its dynamical support with time. It is expected to fall apart
throughout the night...with north Georgia having the greatest
potential to receive light rain.
Friday will be an overall pleasant day...with many of us returning
to more Fall-like temperatures. Aside from perhaps some early
morning fog in the mtns... strong CAA in the wake of the cold front
will allow for generally clear skies...with some post-frontal
stratocu possible. Main concern tomorrow is the wind. Winds will be
noticeably gusty tomorrow out of the NW...with a Wind Advisory
possibly needed...as tight pressure gradient precedes approaching
sfc high. Will let the midnight shift re-evaluate the wind issue.
.LONG TERM /Saturday through Thursday/...
Only tweaks to the long term based on the latest guidance.
A dry weekend with much cooler temperatures is still expected.
Previous Discussion... At one time last week...it appeared we
would may have a deep closed upper low that would keep precip
chances in through the first half of the weekend. Nothing of the
sort is advertised now though with a progressive frontal passage
allowing for upper low to transition to the Carolinas and dry air
to filter in quite readily to the area. With no precip prospects
for the extended...main issue initially will be the temps which
will be the coolest yet of this fall season. Upper 30s possible
for the higher elevations Sat morning and then more
widespread...perhaps sneaking into west central GA for Sunday
morning. Guidance ensembles in good agreement and stuck close to
those for this cycle.
Other issue in the extended will be the fire weather as RH values
dip into the mid to upper 20s on Sat for central zones and remain
there both Sunday and Monday afternoons.
STRONG GUSTY WINDS WILL MOVE OVER THE AREA FOR FRIDAY AND
A HIGH FIRE DANGER STATEMENT FOR WIND WILL LIKELY BE NEEDED. MOST
RELATIVE HUMIDITIES ARE EXPECTED IN THE 30 TO 50 PERCENT RANGE AND
LOWEST OVER CENTRAL GEORGIA.
SATURDAY WILL BE A SIGNIFICANT CONCERN AS RELATIVE HUMIDITIES OVER A
LARGE PORTION OF CENTRAL GEORGIA WILL GET TO 20 TO 25 PERCENT WITH
HUMIDITIES OVER NORTH GEORGIA FORECAST TO BE 25 TO 35 PERCENT. WINDS
ARE EXPECTED IN THE 10 TO 15 MPH RANGE. THESE CONDITIONS WILL BORDER
ON RED FLAG CRITERIA FOR CENTRAL GEORGIA. A HIGH FIRE DANGER STATEMENT
MAY ALSO BE NEEDED FOR SATURDAY...ESPECIALLY FOR CENTRAL GEORGIA.
Records for 10-20
Max Temperature Min Temperature
Station High Low High Low
------- ---------- ---------- ---------- ----------
KAHN 90 1910 47 1989 67 1950 32 1981
KATL 85 1943 47 1913 65 1994 34 1989
KCSG 88 1993 52 1989 70 1969 34 1989
KMCN 91 1943 52 1989 69 1969 32 1967
VFR conditions prevail across the region through a majority of
the forecast period. Line of weakening storms will gradually move
into the region around 21/04-06Z overnight tonight. Expect the
best timing for the metro Atlanta TAF site looks to be around
04-06Z timeframe with best confidence for showers/light rain
around KPDK and KRYY around 03-05Z. Rest of the TAF sites look to
remain clear enough to not include showers in the forecast. Winds
will gradually shift more to the northwest, with gusty winds
around 08-10Z behind the cold front around 10-20kt.
//ATL Confidence...18Z Update...
Medium confidence concerning timing/coverage of showers in the
vicinity of the airfield. High confidence in wind speeds and
direction behind the front.
.PRELIMINARY POINT TEMPS/POPS...
Athens 62 71 43 67 / 20 20 5 0
Atlanta 60 66 44 65 / 40 10 5 0
Blairsville 53 56 37 59 / 50 20 5 0
Cartersville 56 65 40 64 / 50 10 5 0
Columbus 62 74 46 70 / 20 10 0 0
Gainesville 58 64 43 63 / 40 20 5 0
Macon 63 75 43 71 / 20 10 5 0
Rome 55 65 40 66 / 50 10 5 0
Peachtree City 58 68 41 66 / 40 10 0 0
Vidalia 64 77 47 72 / 5 5 5 0