Area forecast discussion
National Weather Service Jacksonville Florida
308 PM EDT Thursday may 23 2013
Rest of the afternoon...water vapor imagery shows dry air aloft
moving into the area in the wake of the a shortwave trough now off
the NE Florida/southeast Georgia coast. Additional weak energy can be seen over southern
Georgia that may be helping isolated small pop-up showers/storms to form
over parts of the forecast area. Mesoanalysis shows MLCAPE of about 1500
j/kg and effective bulk shear of about 20-25 knots in some locations.
Given this and local areas of strong convergence...there is a
potential for an isolated strong storm with gusty winds mainly in
the eastern zones/along the coast through 6 PM.
Short term...
tonight...isolated convection expected over the eastern zones and southeast zones
in the evening. Additional shortwave energy will move into the
region late tonight on northwest flow aloft but airmass looks drier and not
supportive of mentioning even isolated convection. Lows in the lower to
middle 60s. Little if any fog possible tonight. A cold front will also
move into the region late tonight.
Friday...the cold front will move southward over NE Florida in the morning and
S of the area during the day. Mean layer relative humidity from 1000-500 mb looks
to be dropping to 30% or less. Given this and Stout northwesterly flow will
maintain mainly dry weather. Only slight pop over extreme southeast zone. Highs
still could manage upper 80s/near 90. Northwesterly winds expected to
increase to near 15g25-30 miles per hour and could approach lake wind criteria
in a few locations so not expected East Coast sea breeze at this time except
chance of one forming Flagler/southern St Johns counties.
Long term...weekend...a gorgeous weekend expected with dry
conditions and cooler temperatures under northwest flow as high pressure builds
north-northeast of the region. Maximum temperatures will be held in the upper 70s to near
80 along the coast under breezy onshore flow...with highs reaching
the upper 80s toward the Interstate 75 corridor. Min temperatures will
range in the 50s inland to low/middle 60s coast. Not much fog expected
due to dry air in place.
Monday through Friday...an extended period of onshore flow is expected as
surface high pressure over the Atlantic extends an axis over the
Georgia/SC coastline. Mostly dry conditions are expected under mean layer
ridging...but continued to advertise a low 20% chance of passing
coastal showers Tue-Thu. Maximum temperatures will moderate through the period
with values near to slightly above climatology by Thursday with highs near 90
inland to near 80 along the coast. Mins will range to slightly below
climatology from the low 60s inland to near 70 along the coast.
&&
Aviation...trough pushing through the area will produce isolated
showers until around 00z. Have vcsh at all terminals. There may be
some patchy shallow fog at gnv after 06z. Otherwise VFR.
&&
Marine...high pressure will build in behind the cold front
this weekend. Will have NE surge with possible Small Craft Advisory conditions
offshore Friday night into Saturday morning.
Rip currents: low risk today and likely Friday then increasing to at
least moderate category Sat and sun due to NE and east flow.
&&
Fire weather...much drier air will filter over the region this weekend
with afternoon relative humidities falling into the 25 to 30 percent
range inland. Breezy northwest winds and low relative humidity has prompted a Fire
Weather Watch for the Suwannee Valley for Friday afternoon. High
dispersions expected Friday due to mixing...strong transport
winds...and warm afternoon temperatures. Sustained winds will be 15 to 20
miles per hour from the northwest on Friday. Sustained winds will decrease to
less than 15 miles per hour across the inland areas over the weekend...but will
be 15 to 20 miles per hour from the northeast along the coast on
Saturday.
&&
Preliminary point temps/pops...
amg 63 87 53 84 / 10 0 0 0
ssi 69 86 62 76 / 10 10 0 0
jax 67 89 58 80 / 10 10 0 0
sgj 69 88 66 77 / 20 10 0 0
gnv 65 90 58 84 / 20 10 0 0
ocf 66 91 61 85 / 20 10 10 0
&&
Jax watches/warnings/advisories...
Florida...Fire Weather Watch from Friday afternoon through Friday evening
for Baker-Columbia-Gilchrist-Hamilton-Suwannee-Union.
Georgia...none.
Am...none.
&&
$$
Shashy/Peterson/Walker
