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Area forecast discussion
National Weather Service Peachtree City Georgia
657 am EST Tue Nov 12 2019



Update...

Precip is beginning to clear in far northwestern counties earlier
than expected, but a few reports of snow and sleet have been
reported around the area. Given the early clearing of the precip
with widespread temps above freezing, we're expecting no more
than a light flurry or dusting of wintry mix outside areas in the
higher elevations.

&&

Previous discussion... /issued 433 am EST Tue Nov 12 2019/

Short term /today through Wednesday/...

.Brief wintry mix possible in far north Georgia this morning...

Satellite analysis this morning indicates a very impressive
troughing pattern from the eastern Great Lakes down the western
appalachian then over into central Texas. Along it, radar shows a
band of precip, mostly consisting of rain with reports of some sleet
and snow on the rear of the line as an Arctic cold front has quickly
plunged into the northwestern forecast area, which will bring
unseasonably cold temperatures along with it. Behind the front, an
extremely large area of subsidence shows the extent of the Arctic
high pressure behind the frontal system. The center of the high
currently sits in the Central Plains with a central pressure around
1043hpa.

Throughout the morning, the cold front will continue quickly pushing
southeast with the entire forecast area expected to be behind the
front by noon today. Behind the front, strong gradient winds will
prevail with sustained winds up to 20 mph and gusts between 25-35mph
possible. A Wind Advisory has been issued through 7 PM.

As the line of precip moves through the area, most of US will see a
little over a half inch of rain in total with temperatures varying
widely across the forecast area as the cold air move into the
region. In the far northern portions of the forecast area, a race
between subfreezing air moving into the area and drier air behind
the front eroding away the precip will determine if and how much
wintry precip could occur. Model guidance has been very consistent
with this system for several days and have been pushing towards a
transition from rain to a mix of snow and sleet, to a chance for an
hours-Worth of light snow before the precip dries up in the cold,
dry airmass. Chances for any wintry precip will be primarily
confined to the northernmost 2 rows of Georgia counties and will
have the best chances in areas over 2000 feet in elevation. Roads in
these higher elevations could become slick by early morning where
temperatures fall below freezing for an extended period of time. Any
accumulations of wintry precip are expected to be minor and not
cause significant impacts at this time. For more details, please see
the most recent Special Weather Statement.

While temperatures this afternoon are expected to stall as cold air
advection is countered by diurnal heating, tonight temperatures will
plummet once the sun begins going down and the skies clear. These
will be by far the coldest temperatures of the season with Columbus
and Macon in danger of setting record low temperatures. Lows are
forecast around 20 for far north Georgia and mid- to upper-20s are
forecast along and southeast of the I-85 corridor. A freeze warning
has been issued for the remainder of our forecast area where the
autumn frost/freeze program remains in effect.

Tomorrow, the high pressure will be moving across the central
Appalachians into the mid-Atlantic, and will dominate the weather
pattern. Clear skies will allow high temps to climb back into the
mid- to upper-40s, with light winds out of the east becoming breezy
during the afternoon.

Thiem

Long term /Wednesday night through Monday/...

No significant changes made to the long term portion of the
forecast.

High pressure will dominate the weather through the mid to late part
of the week. By Thursday night, a low pressure wave begins to form
in the northern Gulf of Mexico and should move across the central Florida
Peninsula overnight and emerge off the NE Florida coast early Friday.
Aloft, a strong closed upper low will move across the southeast states at
the same time. The GFS and European model (ecmwf) are in better agreement than they
were this time last night. There are still some slight timing
differences with the GFS being just a little faster with the surface
low. This system will bring the next chances for rain, mainly across
east central and southern portions of the outlook area. It will be a
cold rain overnight Thursday and early Friday.

A coastal front looks to remain situated across the northern Gulf of
Mexico...stretching just off the eastern Seaboard. Models prog a
couple of waves to move along this boundary for the remainder of the
weekend into early next week. For now, most of the precip should
stay south/east of the County Warning Area.

Nlistemaa

Aviation...
06z update...
VFR conditions will start to erode away throughout the forecast
area with a cold front moving through the forecast area with ra,
IFR cigs, and lowers visibilities. Obs will likely fluctuate throughout
the night between MVFR and IFR at atl taf sites with most likely
onset between 8-10z. IFR less likely at other taf sites but best
timing is 11-15z for ahn/csg and 14-16z for mcn, timing with the
frontal system and heaviest rain. Vsbys will also be up and down but
most likely to fall to around 3-4sm during IFR ceiling timing. Winds
turning out of the north-northwest this morning gusting up 15-25kts this
afternoon.

//Atl confidence...06z update...
low on vsbys and timing of lower ceilings.
Medium on wind gusts and timing/duration of IFR ceilings.
Medium to high on all other elements up to 18z today.
High on all elements after 18z.

Thiem

&&

Aviation...
12z update...
MVFR/IFR conditions currently ongoing for atl sites with
conditions soon to get to ahn/csg as a cold front continues to
move through the area with moderate rainfall. Vsbys will fluctuate
but have been 3-5sm in heavy rain. Winds behind the front will be
strong out of the north-northwest with sustained speeds of 12-20kts with gusts
up to 25-30kts. Ceilings/vsbys around atl Metro expected to rise by
14-15z with rain clearing between 14-16z.

//Atl confidence...
12z update...
low to medium on vsbys and duration of lower ceilings.
Medium to high on all other elements up to 18z today.
High on all elements after 18z.

Thiem

&&

Preliminary point temps/pops...
Athens 53 26 46 28 / 100 5 0 5
Atlanta 45 26 46 30 / 100 0 0 5
Blairsville 37 19 44 24 / 80 5 0 0
Cartersville 40 22 48 29 / 80 0 0 0
Columbus 54 29 51 34 / 100 0 0 5
Gainesville 46 26 45 29 / 90 0 0 0
Macon 57 28 49 31 / 90 0 0 5
Rome 39 22 49 28 / 70 0 0 0
Peachtree City 46 25 47 30 / 100 0 0 5
Vidalia 67 29 51 35 / 70 10 0 10

&&

Ffc watches/warnings/advisories...
freeze warning from 7 PM this evening to 10 am EST Wednesday for
the following zones: Baldwin...banks...Barrow...Bartow...Bibb...
Bleckley...Butts...Carroll...Chattahoochee...Chattooga...
Cherokee...Clarke...Clayton...Cobb...Coweta...Crawford...crisp...
DeKalb...Dodge...Dooly...Douglas...Emanuel...Fayette...Floyd...
Forsyth...Glascock...Greene...Gwinnett...Hall...Hancock...
Haralson...Harris...heard...Henry...Houston...Jackson...Jasper...
Jefferson...Johnson...Jones...Lamar...Laurens...Macon...
Madison...Marion...Meriwether...Monroe...Montgomery...Morgan...
Muscogee...Newton...north Fulton...Oconee...Oglethorpe...
Paulding...Peach...Pike...Polk...Pulaski...Putnam...Rockdale...
Schley...South Fulton...Spalding...Stewart...Sumter...Talbot...
Taliaferro...Taylor...Telfair...Toombs...Treutlen...Troup...
Twiggs...Upson...Walton...Warren...Washington...Webster...
Wheeler...Wilcox...Wilkes...Wilkinson.

Wind Advisory until 7 PM EST this evening for the following
zones: Barrow...Bartow...Bibb...Butts...Carroll...Catoosa...
Chattahoochee...Chattooga...Cherokee...Clayton...Cobb...Coweta...
Crawford...crisp...Dade...Dawson...DeKalb...Dooly...Douglas...
Fannin...Fayette...Floyd...Forsyth...Gilmer...Gordon...
Gwinnett...Hall...Haralson...Harris...heard...Henry...Houston...
Jackson...Jasper...Jones...Lamar...Lumpkin...Macon...Marion...
Meriwether...Monroe...Morgan...Murray...Muscogee...Newton...
north Fulton...Paulding...Peach...Pickens...Pike...Polk...
Rockdale...Schley...South Fulton...Spalding...Stewart...Sumter...
Talbot...Taylor...towns...Troup...Union...Upson...Walker...
Walton...Webster...white...Whitfield.

&&

$$

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