Scientific Forecaster Discussion
fxus62 kjax 242353
Area forecast discussion
National Weather Service Jacksonville Florida
653 PM EST Fri Nov 24 2017
..cooler tonight with frost potential parts of southeast Georgia and fog
potential parts of NE Florida...
Seasonally cool night expected with below normal min temps
expected across inland southeast Georgia where drier air infiltrated this
afternoon under low level north-northwest drainage flow around the periphery
of surface high pressure building across the Gulf Coast region.
Dew pts fell into the mid to upper 30s across our northwest Georgia zones,
generally northwest of Waycross. If skies were expected to remain cloud
free, the confidence of widespread frost would be elevated across
these southeast Georgia zones, however mid and high clouds are expected to
increase through the night as a mid/upper short wave trough
approaches from the west. Trended min temps down into the
mid/upper 30s from Jesup toward Douglas and included patchy frost.
Confidence of widespread frost not high enough for advisory given
Farther south across NE, clouds will continue to push farther east-southeast
of the region with drier air filtering southward with mostly clear
skies expected by midnight. Due to recent heavy rainfall and
slower erosion of clouds today generally along and south of a
Gainesville to Palatka to Palm Coast line, ground moisture is very
high. With clearing skies, dry air above the surface, and calm
surface winds, included areas of fog after midnight through about
9 am across our southern Florida zones. MOS guidance, sref, hrrr and
nam12 all suggest fog potential as well. May turn into more of low
stratus with some model guidance suggesting elevated boundary
layer winds of 15 kts from the west. More mild temperatures will
range in the upper 40s to lower 50s across these zones.
VFR conditions this evening as moisture continued to shift
farther east-southeast of the terminals. A batch of low cumulus with bases
3-4 kft over gnv is expected to gradually break apart over the
next couple of hours. After midnight, prevailing VFR conditions
were advertised for all terminals except vqq and gnv where
lingering low level moisture could support fog and low stratus.
Trended vqq toward marginal MVFR after midnight with elevated
confidence of restrictions to at least MVFR to potentially IFR at
gnv due to higher low level moisture. After sunrise Sat,
prevailing VFR expected under west winds 10 kts or less.
Developing offshore winds this evening are expected to gradually
decrease with seas subsiding through midnight below advisory
levels, but based on recent obs will need to extended Small Craft Advisory for Florida
near shore waters. At 6 PM EST, Grays Reef buoy 41008 was down to
5 ft and winds were north 14g18 kts and the Fernandina Beach buoy
41112 reported 5 ft seas. The St. Augustine C-man sauf1 measured north
winds 20g21 kts at 6 PM and buoy 41117 offshore of St. Augustine
measured wave heights of 7-8 ft. Will drop the advisory for the
near shore Georgia waters and replace with scec then will extended the
near shore advisory through 1030 PM this evening for the near
shore Florida waters due to recent observations.
Rip currents: moderate risk this evening. Potential for low risk
for portions of the local coast Saturday due to offshore flow and
Preliminary point temps/pops...
amg 39 69 45 67 / 0 0 0 0
ssi 48 69 51 66 / 0 0 0 0
jax 47 71 48 68 / 0 0 0 0
sgj 49 70 51 68 / 0 0 0 0
gnv 48 72 47 70 / 0 0 0 0
ocf 49 73 48 72 / 0 0 0 0
Am...Small Craft Advisory until 11 PM EST this evening for coastal
waters from Fernandina Beach to St. Augustine Florida out 20 nm-
coastal waters from St. Augustine to Flagler Beach Florida out
20 nm-waters from Altamaha Sound Georgia to Fernandina Beach Florida
from 20 to 60 nm-waters from Fernandina Beach to St.
Augustine Florida from 20 to 60 nm-waters from St. Augustine to
Flagler Beach Florida from 20 to 60 nm.