Special Weather Statement, NWS Jacksonville, FL

Area Forecast Discussion
National Weather Service Jacksonville FL
546 AM EDT Wed Apr 5 2017

...INCREASED THREAT OF ORGANIZED SEVERE THUNDERSTORMS TONIGHT...

.NEAR TERM /Through Tonight/...

Low stratus/patchy fog along the I-75 corridor should lift by mid
morning. There is a low chance of a shower or thunderstorm near
the Altamaha River basin early this morning, otherwise, the rest
of the morning will remain dry. Warm and windy southwest flow will
result in near record max temps across northeast Florida (Previous
records for this date: 89 at JAX in 1880 and 90 at GNV in 1999).
Warmest temps today will be along the I-95 corridor of northeast
Florida (lower 90s).

A strong LLJ will move over our area this afternoon. We almost
pulled the trigger on a wind advisory as model soundings indicate
that it will be very close, especially across southeast Georgia
late this afternoon. The day shift will have to take a closer look
at this since there is certainly some potential there for wind
gusts in excess of 35 mph.

A few thunderstorms will be possible near the Atlantic coast this
afternoon and also near the Altamaha river basin, but the bulk of
the activity will hold off until later tonight.

The ingredients continue to be in place to support an organized
severe weather event tonight. A squall line (QLCS) on the leading
edge of a fairly strong late season upper trough will approach
Southeast Georgia by early this evening, and then move through
our area overnight, perhaps as late as 4 or 5 am before reaching
areas along the I-95 corridor.

Latest model guidance indicates 6KM bulk shear of around 60 KTS
coupled with instability around 2000 J/KG. The large scale ascent
and upper level support coupled with these shear/cape values will
be supportive of severe thunderstorms tonight. We have added
enhanced wording to the forecast to indicate this potential and we
may need to ramp it up even further, depending on how things
evolve later on today.

As it stands now, the environment tonight will be favorable for
thunderstorms capable of producing damaging wind gusts, isolated
tornadoes, intense lightning strikes, and very heavy downpours.
Unlike last night, the storms will be moving at a fairly good
pace, so the threat of significant flooding should be minimized.
Most areas should average around a half inch to an inch, but
localized rainfall amounts in excess of an inch will be possible.

All storms should push off the coast by sunrise, with windy
conditions expected in the wake of the cold front/squall line as
cooler and much drier air begins to filter into the region.

.SHORT TERM /Thursday Through Friday Night/...

Strong cold front is forecast to be along the southern border of
the region Thursday morning, with much drier air and cooler
conditions prevailing through the short term period. An upper
level trough will be across the eastern conus Thursday morning,
with the trough axis moving east and northeast of the region
Thursday morning. A shortwave over the northern/central Plains
will push another trough axis through the region on Friday,
reinforcing the drier and cooler air over the area.

A few lingering showers are possible across the southern portion
of the area Thursday morning. Otherwise, breezy to windy westerly
winds of 15 to 25 mph with gusts up to 40 mph will prevail on
Thursday, with the highest winds over southeast Georgia. A Wind
Advisory will likely be required for portions of the region on
Thursday. Winds are forecast to remain in the 5 to 15 mph range
overnight Thursday night. Breezy conditions are expected again on
Friday, with west to northwest winds 15 to 20 mph with gusts up
to 30 mph possible. Sunny/clear skies are forecast to prevail.

Highs will go from well above normal in the 80s to lower 90s
earlier in the week to below normal on Thursday, with temperatures
in the mid 60s to lower 70s across southeast Georgia, and the low
to mid 70s across northeast Florida. Overnight lows will be 10 to
20 degrees colder, with temperatures in the 40s inland and near
50 to low 50s along the St Johns River and at the coast. Highs on
Friday are forecast to be even cooler, with highs in the mid to
upper 60s across southeast Georgia, and the upper 60s to lower 70s
across northeast Florida.

.LONG TERM /Saturday Through Wednesday/...

Upper levels: Northwesterly flow aloft will prevail on Saturday
with an upper trough over the northeastern conus and along the
eastern sea board. An upper ridge will be over the middle of the
country, with a trough pushing into the western conus. A shortwave
will move southeast from the northern Plains Saturday morning in
the northwesterly flow aloft and into the southeast states by
Saturday evening, with the shortwave deepening and cutting off
into an upper low across the Bahamas by Monday. The upper low will
then remain near the Bahamas through the middle of the week. The
shortwave across the western conus on Saturday will push into the
Plains states Sunday night, and upper ridging will build over the
eastern conus through early next week. The upper trough is then
forecast to push towards the eastern conus by the middle of the
week, with a surface cold front pushing into the southeast.

Surface and Temps: High pressure just to the west of the region on
Saturday will build over the region and to the coast of the
Carolinas on Sunday. Cool temperatures will continue on Saturday.
Highs will be in mid to upper 60s along the coast as a light
onshore flow develops in the afternoon, with low 70s inland.
Overnight lows will be in the low to mid 40s inland and the upper
40s to lower 50s along the east coast. The ridge will continue to
shift to the northeast through early next week. The high will
shift to east of the northeastern conus by Monday night and
Tuesday. Easterly low level flow will prevail through Tuesday,
with warming temperatures and increasing moisture. A couple
showers cannot be ruled out on Tuesday across northeastern
Florida. Otherwise dry conditions with seasonable temperatures
are forecast Sunday through the middle of the week.

&&

.AVIATION...

Prevailing VFR conditions Today, however, occasional IFR
conditions will be possible in patchy fog/low stratus at GNV early
this morning. Southwesterly winds will become rather gusty Today,
especially late this afternoon into this evening. A squall line is
expected to move across the area tonight with an increased threat
of severe thunderstorms capable of producing damaging winds,
intense lightning, and heavy downpours.

&&

.MARINE...

Southerly winds will increase to SCEC levels this afternoon across
the offshore waters. A strong cold front will push a squall line
across the waters late tonight. Severe thunderstorms within the
squall line will be capable of producing damaging winds, excessive
lightning, and heavy downpours. Southwesterly winds will increase
to SCA levels this evening ahead of the squall line. Winds will
veer to the west behind the cold front with winds increasing into
the 20 to 30 knot range with gusts to gale force expected with the
squall line and occasionally thereafter through mainly Thursday
morning. A prolonged period of SCA conditions will then continue
through the end of the week as unseasonably colder air moves
across the warmer ocean waters. No headlines will be needed for
the upcoming weekend as high pressure builds in from the west.

Rip Currents: Low Risk due to offshore flow.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  83  57  68  45 /  70  70   0   0
SSI  82  61  70  49 /  50  70  10   0
JAX  89  62  73  47 /  30  70  10   0
SGJ  88  65  75  51 /  30  70  10   0
GNV  88  63  72  46 /  30  70  10   0
OCF  89  64  74  47 /  30  70  10   0

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&

Shuler/Kennedy/

Hazardous Weather Outlook
National Weather Service Jacksonville FL
610 AM EDT Wed Apr 5 2017

AMZ450-452-454-470-472-474-FLZ020>025-030>033-035>038-040-124-125-
GAZ132>136-149>154-162>166-061015-
Coastal waters from Altamaha Sound to Fernandina Beach FL out
20 NM-
Coastal waters from Fernandina Beach to St. Augustine FL out
20 NM-
Coastal waters from St. Augustine to Flagler Beach FL out 20 NM-
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-
Hamilton-Suwannee-Columbia-Baker-Inland Nassau-Inland Duval-Union-
Bradford-Clay-St. Johns-Gilchrist-Alachua-Putnam-Flagler-Marion-
Coastal Nassau-Coastal Duval-Coffee-Jeff Davis-Bacon-Appling-
Wayne-Atkinson-Ware-Pierce-Brantley-Inland Glynn-Coastal Glynn-
Echols-Clinch-Charlton-Inland Camden-Coastal Camden-
610 AM EDT Wed Apr 5 2017

...INCREASED RISK OF ORGANIZED SEVERE THUNDERSTORMS TONIGHT...

...SMALL CRAFT ADVISORY IN EFFECT...

This Hazardous Weather Outlook is for Northeast Florida,
Southeast Georgia and the Adjacent Coastal Waters.

.DAY ONE...Today and Tonight...

A strong cold front will surge into the southeastern states this
afternoon. Southwesterly winds will become gusty area-wide by the
early afternoon hours, and we will have to keep a close eye on
the possibility of a wind advisory by late this afternoon.

The threat of thunderstorms will begin to increase over inland
portions of southeast Georgia by mid to late this afternoon.
Conditions aloft will become increasingly favorable for strong to
severe thunderstorm development by the late afternoon and early
evening hours across inland southeast Georgia and the western
Suwannee Valley. The Storm Prediction Center has included these
areas within Enhanced to Moderate Risk for severe thunderstorm
development, especially during the evening hours as activity
organizes into a squall line that will move rapidly eastward.
Damaging wind gusts in excess of 60 mph, hail, and tornadoes will
be possible with this activity throughout the evening hours.

The squall line will progress eastward across the rest of
southeast Georgia and northeast Florida during the late evening
and pre-dawn hours with a continued threat of damaging wind gusts,
isolated tornadoes, hail, excessive lightning, and very heavy
downpours.

Strong offshore winds will develop over the coastal waters in
advance of the front tonight and small craft advisories are in
effect for all coastal waters. Gusts to gale force can be expected
late tonight as the squall line moves across the waters just prior
to sunrise.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday...

Very windy conditions are expected on Thursday and a wind advisory
will be likely.

Small craft advisories will remain in place through the end of the
week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is expected over southeast Georgia and the
Suwannee Valley by late this afternoon. Spotters elsewhere should
be ready to activate this evening.

For additional information, visit the National Weather Service in
Jacksonville website on the internet at weather.gov/jax.

JDS

Special Weather Statement
National Weather Service Jacksonville FL
431 PM EDT WED APR 5 2017

GAZ162-163-052100-
Clinch GA-Echols GA-
431 PM EDT WED APR 5 2017

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL ECHOLS AND CLINCH
COUNTIES UNTIL 500 PM EDT...

At 431 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from Du Pont to 12 miles south of Homerville to 8
miles west of Needmore. Movement was northeast at 30 mph.

Nickel size hail and Wind gusts of 45 to 55 mph can be expected along
with possible minor damage.

Locations impacted include...
Homerville, Argyle, Du Pont and Cogdell.

LAT...LON 3118 8281 3118 8267 3102 8259 3100 8255
      3096 8252 3096 8249 3082 8250 3082 8249
      3078 8250 3065 8286 3082 8281 3102 8297
      3104 8297
TIME...MOT...LOC 2031Z 232DEG 28KT 3101 8289 3085 8277 3070 8281

ELSENHEIMER

Special Weather Statement
National Weather Service Jacksonville FL
444 PM EDT WED APR 5 2017

GAZ132-133-052130-
Coffee GA-Jeff Davis GA-
444 PM EDT WED APR 5 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN COFFEE AND JEFF DAVIS
COUNTIES UNTIL 530 PM EDT...

At 444 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Lumber City to near Pridgen. Movement was
east at 35 mph.

Nickel size hail and Wind gusts of 45 to 55 mph can be expected along
with possible minor damage.

Locations impacted include...
Hazlehurst, Broxton, Ambrose, Pridgen, Snipesville, Denton and Grays
Landing.

A tornado watch remains in effect until 800 PM EDT for southeastern
Georgia.

LAT...LON 3197 8243 3184 8243 3184 8252 3175 8252
      3175 8255 3174 8255 3173 8252 3167 8252
      3167 8262 3166 8263 3160 8303 3166 8300
      3170 8300 3192 8267 3193 8259 3196 8255
      3195 8248 3196 8250 3197 8248
TIME...MOT...LOC 2044Z 252DEG 32KT 3194 8260 3168 8299

ELSENHEIMER

Special Weather Statement
National Weather Service Jacksonville FL
513 PM EDT WED APR 5 2017

GAZ150-152-164-052145-
Ware GA-Brantley GA-Charlton GA-
513 PM EDT WED APR 5 2017

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN BRANTLEY...EAST
CENTRAL WARE AND NORTHWESTERN CHARLTON COUNTIES UNTIL 545 PM EDT...

At 513 PM EDT, Doppler radar was tracking a strong thunderstorm 11
miles north of Stephen Foster State Park, moving northeast at 45 mph.

Nickel size hail and Wind gusts of 45 to 55 mph can be expected along
with possible minor damage.

Locations impacted include...
Fort Mudge and Braganza.

LAT...LON 3122 8231 3121 8221 3120 8219 3121 8218
      3107 8195 3106 8199 3108 8206 3103 8208
      3099 8229 3090 8242 3090 8243 3098 8249
TIME...MOT...LOC 2113Z 236DEG 41KT 3099 8239

ELSENHEIMER