Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/19/20
Area Forecast Discussion
National Weather Service Jacksonville FL
909 PM EST Sat Jan 18 2020
Southerly low level flow over the area this evening with a cold
front analyzed from ern TN to southeast LA pushing eastward.
Cold front should be entering our northwest zones by 12z Sunday.
Flow aloft fairly progressive from the west with plenty of moisture
and lift ahead of the front to produce scattered to numerous
showers from nrn GA to the FL panhandle and westward over to
southeast LA. Some areas of widespread precip, and lightning noted
over the GOMEX where instability is maximized. With time, some of
the showers will be moving into our wrn zones overnight and have
adjusted up POPs a bit tonight and Sunday. Main area of rain/showers
will be pushing through Sunday morning with POPs fcst around the
60-70 percent range. Slim chance for rumble of thunder on Sunday,
mainly over northeast FL, and also where the best QPF values are.
Amounts of up to around 1/3 of an inch expected at this time.
Precip expected to be exiting our northeast FL zones late Sunday
aftn as the front presses through the rest of the area. Temps
tonight only slowly fall to the upper 50s to lower 60s given sly
flow and increased cloudiness.
Current marine forecast on track. Winds generally south up to
15-20kt tonight, perhaps a little stronger near 40-60 nm out. Seas
per latest buoys are on track with latest NWPS guidance. SCEC
nearshore and SCA offshore look good at this time.
.PREV DISCUSSION [701 PM EST]...
.Near Term.../Through Tonight/...
High pressure to the east this afternoon, will move to the southeast
Tonight as a cold front approaches from the northwest. This front
will reach SE GA by dawn. Scattered showers expected along the
front, with a few showers ahead of it as well. Expect dry weather to
continue through around midnight, with chances then through the
night. Temperatures will remain above normal Tonight.
.Short Term.../Sunday through Wednesday/...
The cold front is expected to move southeast across the region
during the day Sunday. Scattered showers will accompany the frontal
passage, and noticeably cooler air will arrive following passage.
Due to the enhanced pressure gradient, winds will become gusty
behind the front. Skies will clear Sunday night, as cooler air
continues to filter in. Temperatures will fall to around freezing
across inland SE GA, while holding in the lower to mid 40s near
the coast. Strong high pressure will build from the northwest
Monday through Monday night, then to the north Tuesday through
Wednesday. This will be a cooler than normal period, with freezes
inland Monday night and Tuesday night. As the high moves more to
the north by Wednesday, the flow will become more onshore with the
potential for a coastal trough developing, with a few coastal
showers becoming possible.
.Long Term.../Wednesday night through Saturday/...
High pressure will be centered to the north Wednesday night through
Friday, then toward the northeast Friday night and east on Saturday.
Low pressure will move northeast out of the gulf across the region
Friday night into Saturday.
While the high is to the north Wednesday night through Friday, the
largely onshore flow will continue, with weak coastal troughing.
A chance for mainly coastal showers expected during this time. As
the low lifts out of the gulf, shower chances will increase late
Friday through Saturday.
Temperatures will recover back to around normal Wednesday night
through Thursday, then above normal Thursday night through Saturday.
[Through 00Z Monday]
VFR still expected much of tonight ahead of the approaching cold
front. We do anticipate increased multilayered clouds through the
night, with winds becoming light southerly.
HRRR and GFS guidance show precip moving into the TAF sites early
Sunday morning, and still expecting low cigs at MVFR to move in
between about 11z and 16z, which may linger through the aftn
hours. VCSH begins around 09z-10z, and showed TEMPO precip for
showers during the 10z-18z time frame, varied based on TAF
location. VCSH at times also after 18z mainly for GNV and SGJ.
Still some potential for IFR cigs Sunday morning but not confident
in this at this time but indicated scattered clouds at 700-1000
ft. A marginal case for LLWS ahead of the front with southwest
winds at 1000-2000 ft approaching 35-40 kt. Winds on Sunday will
be southwesterly 10-15 kt, becoming west and west-northwest around
10 kt and gusty in the late aftn and early evening.
High pressure will move southeast of the region through Tonight. A
cold front will move southeast across the area Sunday, with strong
high pressure building from the northwest Sunday night. High
pressure will remain to the northwest through Tuesday, then to the
north through Friday.
Rip Currents: SE GA low risk Sunday
NE FL moderate risk Sunday
.PRELIMINARY POINT TEMPS/POPS...
AMG 58 64 32 50 29 / 60 60 0 0 0
SSI 61 67 38 51 35 / 40 50 0 0 0
JAX 60 71 37 55 34 / 30 60 0 0 0
SGJ 61 73 40 56 39 / 30 60 10 0 0
GNV 59 71 37 56 32 / 30 60 10 0 0
OCF 59 72 38 58 33 / 30 60 10 0 0
FL...High Rip Current Risk until 4 AM EST Sunday for Coastal Duval-
Coastal Flagler-Coastal Nassau-Coastal St. Johns.
AM...Small Craft Advisory until 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.