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Area forecast discussion 
National Weather Service Peachtree City Georgia 
1044 PM EDT sun Mar 21 2010 


Update... 
line of showers/isolated thunderstorms now east of the County Warning Area and 
moving into the Carolinas. Expect broad area of clouds associated 
with strong upper low centered over Alabama to spread into our 
area overnight...with spits of light rain and drizzle. Will 
continue mention of rain/snow mix in the norhtheast mountains 
late tonight into Monday morning. 


49 
&& 


Previous discussion... /issued 630 PM EDT sun Mar 21 2010/ 


Short term /tonight through Tuesday night/... 
current radar loop shows isolated to scattered showers over the area 
with a line of showers and isolated thunderstorms moving in from 
Alabama. This line is right along the cold front and is expected to 
be east of our area by 06z Monday. Currently these storms do not look 
severe and they will be moving into a more stable environment so not 
expecting more than just isolated thunder through 06z. Once the 
front moves through good backside moisture will wrap around the main 
surface low and continue to keep rain over the area through early 
Tuesday morning (mainly over north ga). There is a 50-60kt low level jet moving over 
the state just ahead of the line with some of these winds mixing 
down to the surface. Have seen gust in the 20-25kt range with 
isolated gust in the 30kt range. Still looks like things are below 
Wind Advisory criteria and the low level jet is expected to weaken as it moves 
NE through 00z. There has also been not much precipitation with this as 
most places have seen 0.1-0.2 inches of rain so far. Should see 
another 0.5 inch as the line passes through later this evening but 
still not enough to cause any concern for flooding. There is a low 
level cold pool that is associated with the upper low with 800 mb temperatures 
around -5c over north Georgia Monday morning. May see some rain/snow mix 
across the north Georgia mountains Monday morning (areas mainly above 2500 ft). 
The last of the wrap around moisture finally moves out Tuesday morning 
with skies clearing out after that. 


Long term /Wednesday through Sunday/... 
a high pressure ridge begins building into the state from the 
Southern Plains/northern Gulf Tuesday and dominated the weather pattern 
through the end of the week. Looks like we will start to see some 
increased moisture Friday morning from the next frontal system that is 
expected to move in Friday afternoon/evening. It looks to move through 
very quickly and does not seem to have much instability with it 
either. For now will keep a slight chance of showers in the forecast 
for Friday afternoon/evening. 


01 


Aviation... 
deep closed upper low across the middle-south will continue moving 
toward the southeast U.S. A leading surface cold front extended from northwest to wc 
Georgia at 22z...and will move quickly into East Georgia this evening. A 
narrow line of +shra and isolated +tsra with 27020g30kt will accompany 
the front...moving past atl by 00z and ahn by 01z. Scattered rain showers will 
continue ahead of the front across East Georgia until the line passes. A 
large pocket of cold air at 850mb wraps into the back side of the 
upper low and helped produce a large area of moderate to heavy snow 
across North Texas and the arklatex region. This pocket of cold air will 
spread across north Georgia after 04z...and remain in place through taf valid 
period. Cold air SC will quickly spread across the County Warning Area after 04z...and 
remain in place through the remainder of the period as the center of 
the upper low drifts near the area. After rain showers move past taf 
sites...brief dry slot will yield a very brief scattered period from atl 
southward through 02z...with MVFR SC settling in after 04z. Taf valid 
period will generally be characterized by MVFR ceilings and VFR visibility after 
rain showers/thunderstorms and rain exit the area. Cold air aloft and proximity of upper low 
will likely yield rain showers for Monday afternoon. Any snow should remain 
north of atl. Southeast-south-southeast winds 15-20kts in advance of line of rain showers/thunderstorms and rain 
become SW-west-southwest 10-15kts behind...which will hold most of remainder of 
taf valid period...except as noted above in rain showers/thunderstorms and rain activity. 


19 


&& 


Preliminary point temps/pops... 
Athens 39 50 38 65 42 / 70 40 20 5 0 
Atlanta 37 49 39 63 45 / 40 30 10 5 0 
Blairsville 37 44 37 57 41 / 70 40 30 5 0 
Cartersville 34 50 39 63 39 / 40 40 30 5 0 
Columbus 40 53 42 65 44 / 20 20 5 5 0 
Gainesville 38 47 39 61 44 / 60 40 30 5 0 
Macon 40 55 40 68 41 / 40 20 5 5 0 
Rome 37 46 43 63 40 / 50 50 30 5 0 
Peachtree City 35 49 36 63 38 / 40 30 10 5 0 
Vidalia 44 61 44 70 47 / 40 10 5 5 0 


&& 


Ffc watches/warnings/advisories... 
none. 
&& 


$$ 


01