Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 211940
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
240 PM EST Sat Jan 21 2017

...TORNADO WATCH IN EFFECT FOR PORTIONS OF SOUTHEAST GEORGIA
THROUGH 7 PM THIS EVENING...

.NEAR TERM /Through Sunday/...

Squall line moving eastward around 50 mph into southeast Georgia
this afternoon. Other convection was developing out ahead of the
line in southeast Georgia as well. A Tornado Watch is in effect
until 7 PM for the portions of southeast Georgia. Straight line
wind damage, large hail, and isolated tornadoes are possible. The
broken line and additional cells are forecast to push quickly east
while weakening along/south of the I-10 corridor this evening.
Temperatures have warmed into the mid 70s to lower 80s across the
region. A record high was set at Jacksonville International
Airport of 84 degrees this afternoon, which breaks the old record
of 83 degrees set back in 1929.

Tonight: There remains considerable uncertainty for the forecast
tonight. The severe parameters will increase across the region,
including deep level shear and low level helicity. However, it is
unclear if the atmosphere will be able to recover after the
convection moves through southeast Georgia this afternoon. Most
models are not extending convection southwestward into the Gulf
from the MCS that is forecast to track north of the region along
the stalled boundary well north of the area overnight. However,
the ECMWF has been very consistent with an additional convective
cluster developing overnight, and then moving into the Suwannee
River valley and western portions of southeast Georgia. If this
convection does develop like the ECMWF and a few other models
suggest, strong tornadoes (EF2 or greater) could be possible
across the extreme western portion of the region late tonight.
Mostly cloudy to cloudy skies will prevail overnight, and lows
will be in the low to mid 60s.

Sunday: Upper level low will move into the Arklatex region Sunday
morning and then push east into northern Alabama by the evening.
An area of low pressure will develop across the southeast and
rapidly deepen as it moves northeast into northern Georgia and
merges with another area of low pressure to the west. A squall
line is likely to develop and push through the region in the
afternoon. All modes of severe weather are possible, with the
largest threats being damaging straight line winds of 60-80+ mph,
and isolated tornadoes in the QLCS line. Discreet cells could also
develop out ahead of the line. Quarter sized hail is also
possible.


.SHORT TERM /Monday and Tuesday/...
Monday: A few light showers are possible Monday morning in the
wrap around moisture. Westerly flow will continue through the day,
so temperatures are not forecast to be significantly colder. Highs
will be closer to normal in the 60s. Lows are forecast to be in
the 40s.

Tuesday: High pressure will build east from the central Gulf
towards the Florida peninsula as an area of low pressure moves
northeastward across the central plains. Near normal temperatures
are forecast for Tuesday, with highs in the 60s. Lows are forecast
to be in the low to mid 40s.

.LONG TERM /Wednesday through Friday/...
Wednesday: An area of low pressure will move across the northern
Great Lakes on Wednesday, and a cold front will push into the
southeast. Surface high pressure will shift east into the western
Atlantic, and the flow will shift to the southwest by the evening.
Temperatures will warm back into the low to mid 70s. Lows are
forecast to be in the mid to upper 50s Thursday morning.

Thursday: A strong cold front is forecast to push into the region
during on Thursday and Thursday evening, bringing a chance of
showers to the region. Highs are forecast to be cooler across
southeast Georgia, in the mid 60s to near 70, but remain in the
low to mid 70s for northeast Florida. Lows Thursday night are
forecast to be near 40 to to the lower 40s across southeast
Georgia, and the 40s across northeast Florida.

Friday: Much cooler conditions are forecast by the end of the
week behind the cold front. Highs are forecast to be in the 50s to
lower 60s, with lows Saturday morning in the mid 30s to lower 40s.

&&

.AVIATION...
VFR conditions through the afternoon with breezy south to
southwesterly winds 10-15 knots with gusts to around 25 knots. A
weakening line of convection may move into the region this evening
and dissipate before midnight. The low level jet will strengthen
overnight, bringing in stratus. MVFR ceilings are forecast
overnight, and then may continue through much of the day on
Sunday. A squall line is forecast to push into the region on
Sunday, possibly near or after the end of the current TAF period.
Winds could gust to 40 mph near the end of the TAF period ahead of
the squall line, with severe gusts along the squall line in the
afternoon.


&&

.MARINE...
Strong area of low pressure will push across the southeast, a
strong wind gradient will develop behind it. Small Craft
Advisories are in effect for the offshore waters starting tonight.
A Gale Watch is in effect for the offshore waters beginning 21Z on
Sunday and continuing through 04Z on Tuesday. West to southwest
winds will increase to 30-35 knots offshore with gusts to 40 knots
possible. A Small Craft Advisory is in effect for the nearshore
waters beginning 15Z on Sunday and continuing through 15Z on
Tuesday. Seas will build to 6-10 feet offshore Sunday through
Monday night.

Rip currents: Low to moderate risk of rip currents through Monday.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  64  77  52  63 /  80  90  20  10
SSI  64  73  55  65 /  70  90  50  10
JAX  65  80  56  66 /  60 100  40   0
SGJ  66  80  57  68 /  30 100  70  10
GNV  65  79  54  66 /  50 100  50  10
OCF  65  80  56  67 /  30 100  60  20

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...Gale Watch from Sunday afternoon through Monday evening for
     Waters from Altamaha Sound GA to Fernandina Beach FL from
     20 to 60 NM-Waters from Fernandina Beach to St. Augustine
     FL from 20 to 60 NM-Waters from St. Augustine to Flagler
     Beach FL from 20 to 60 NM.

     Small Craft Advisory from 11 PM this evening to 4 PM EST Sunday
     for Waters from Altamaha Sound GA to Fernandina Beach FL
     from 20 to 60 NM-Waters from Fernandina Beach to St.
     Augustine FL from 20 to 60 NM-Waters from St. Augustine to
     Flagler Beach FL from 20 to 60 NM.

     Small Craft Advisory from 10 AM Sunday to 10 AM EST Tuesday for
     Coastal waters from Altamaha Sound to Fernandina Beach FL
     out 20 NM-Coastal waters from Fernandina Beach to St.
     Augustine FL out 20 NM-Coastal waters from St. Augustine to
     Flagler Beach FL out 20 NM.

&&

$$

Kennedy/Kennedy/Guillet


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