Area Forecast Discussion
Issued by NWS Jacksonville, FL
FXUS62 KJAX 060226
Area Forecast Discussion
National Weather Service Jacksonville FL
926 PM EST Mon Dec 5 2016
...Tornado Watch #516 for Hamilton and Suwannee Counties in N FL
through 5 am...
...Tornado Watch $516 for Atkinson, Clinch, Coffee, and Echols
County in SE GA through 5 AM...
.UPDATE...Upper level trof resides over East Texas at this time
with a stationary front extending from southern Louisiana into
the FL Panhandle across SE GA and NE FL across the FL/GA line. At
this time, instability is marginal with best shear well removed to
our northwest over central Georgia. Extensive Light to moderate
rain shield with some isolated embedded thunderstorms has spread
eastward into southeast Georgia this evening north of the
stationary boundary. Moisture will continue to increase tonight
ahead of low pressure that will lift northeast from the western
gulf coast region into the ArkLaMiss region by 12z and into middle
TN by mid Tuesday morning. As this upper level system drifts
northeast, low level flow increases resulting in increasing
unidirectional shear, particularly over the western portions of
SE GA and Suwannee Valley, which may lead to a few of storms
becoming strong to marginally severe with gusts potentially having
wind gusts of 40 to 60 mph. The best storm relative helicity will
be near over the Western parts of the CWA between 1 am and 5 am as
the frontal boundary nudges slightly northward in the marginally
unstable environment. With this said, there is a small potential
for a quick spin up tornado across interior western sections of SE
GA and the Suwannee Valley of NE Florida during the overnight
hours with localized backing of surface winds near this boundary
for enhanced 0-1 km helicity values. Hence, Tornado Watch 516 has
been issued through 5 am for the western counties of interior SE
GA and portions of the Suwannee Valley. Precipitation chances will
increase across northeast Florida region very late this evening
into the overnight hours and have trended PoPs this way...with
slight chances of embedded thunderstorms as the nocturnal hours
progress. Another line of convection may move into the region
sometime after 14Z ahead of the upper trough and extended vort
lobe, bringing a potential round/threat of severe weather with it.
A dry slot will then move in behind the area of low pressure by
the afternoon, and the line of convection may begin to weaken as
it treks towards the east coast before 18Z followed with a 3 hour
window of breezy west winds with FROPA. Latest WPC and model
guidance suggest the heaviest rainfall axis will set up north and
west of GA state route 84 (along and northwest of a line from
Homerville-Waycross to Jesup) where rainfall amounts of 2 to 3
inches are possible over the next 12 to 16 hours with 1/2" to 1.5"
.AVIATION...Ceilings will lower tonight with IFR/LIFR conditions
possible as a strong low level jet develops. Showers and storms
are possible at the TAF sites, especially after midnight lasting
for coastal TAFS sites between 15-18Z. Shra becmg sct/nmrs
overnight along with potential for isold tsra. SW winds increase
to around 15kt with ocnl gusts above 20kt daytime Tue for 3-4 hour
window following FROPA. Showers and embedded thunderstorms push
offshore after 18z with partial clearing and cigs scattering out
and becoming VFR.
.MARINE...Warm front currently resides near the mouth of St.
Mary`s and will lift north tonight with increasing southerly
winds. Small Craft Advisory conditions will develop late tonight
beyond 20nm offshore and continue into Tuesday afternoon ahead of
a cold front. Front will move across the waters Tuesday evening
ending the chance for showers and thunderstorms. Weak high
pressure will build into the region, with diminishing winds and
seas. Another cold front will increase winds late Thursday through
Friday with another Small Craft Advisory likely.
Rip Currents: Low risk today and moderate on Tuesday.
.PRELIMINARY POINT TEMPS/POPS...
AMG 62 79 52 70 / 90 70 0 0
SSI 66 81 57 68 / 80 70 0 0
JAX 69 85 53 72 / 60 60 0 0
SGJ 68 86 53 72 / 50 60 0 0
GNV 69 80 52 75 / 60 60 10 0
OCF 70 80 54 75 / 60 60 0 0
AM...Small Craft Advisory from 4 AM to 4 PM EST Tuesday 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.