Area forecast discussion
National Weather Service Jacksonville Florida
1011 PM EDT Tuesday may 21 2013
Update...
evening surface analysis depicts the axis of Atlantic ridging
positioned over our region. Aloft...a slow moving and weak upper
level low/cold pool persists over our region...with ridging
otherwise aligned over the eastern United States. Convection
developing on the west side of the upper level low moved
south/southwestward across the Altamaha river during the late
afternoon hours. This convection moved into Jeff
Davis/Coffee/Atkinson counties and collided with outflows from
earlier sea breeze convection to produce damaging wind gusts and
small hail...with numerous reports of trees and power lines downed
in the Douglas area (coffee county). This convection has
propagated southwestward and has weakened with the loss of diurnal
heating...and trailing anvil rains will soon dissipate over far
southeast Georgia and northern portions of the Suwannee Valley. Other
isolated showers in north central Florida should also dissipate as the
evening progresses.
High altitude debris clouds from earlier convection will decrease
overnight. Moist dewpoints and light winds should allow for
patches to areas of fog to develop after midnight nearly region-
wide. Lows will generally fall to near our current dewpoint
temperatures...or in the middle-upper 60s. We expect fog to quickly
lift after sunrise...and another day of sea breeze driven
convection is expected on Wednesday afternoon following plenty of
morning insolation.
&&
Aviation...
with grounds moist from recent heavy rain...will go with areas of
fog at all NE Florida terminals later tonight. Have prevailing MVFR
visibility at gnv and occasional MVFR visibility at jax...crg...and vqq between 08z-
12z. The upper low is forecast to be just offshore the Florida East
Coast on Wednesday. Have gone with persistence with scattered
showers/storms along the NE Florida coast in the morning and pushing
inland with the East Coast seabreeze in the afternoon. Have thunderstorms in the vicinity
at crg... jax...vqq after 16z. Have thunderstorms in the vicinity at gnv after 18z and with
best coverage of storms inland and put a prob30 group there for
storms. Have vcsh at ssi after 15z.
&&
Marine...
southeast to south winds expected through Wednesday with combined seas
2-4 feet. Winds shift to offshore Thursday/Thursday night ahead of an
approaching frontal system...although weak flow will allow sea
breeze to form near shore Thursday afternoon. High pressure building
north of the area Friday will produce a stronger NE flow through the
weekend and Small Craft Advisory headlines are expected for offshore legs with
speeds around 20 knots and seas building to 5-7 feet. Expect scec
conditions near shore.
Rip currents: moderate risk through Wednesday...mainly during the
morning outgoing tide. Onshore flow and a persistent easterly
swell will contribute to the enhanced risk.
&&
Preliminary point temps/pops...
amg 64 89 66 91 / 70 40 40 30
ssi 69 81 70 85 / 10 30 20 30
jax 66 85 67 89 / 30 30 30 30
sgj 67 83 68 85 / 10 30 30 30
gnv 64 87 67 89 / 30 50 40 20
ocf 66 88 67 89 / 20 50 40 30
&&
Jax watches/warnings/advisories...
Florida...none.
Georgia...none.
Am...none.
&&
$$
Nelson/Peterson/guillet
