textproduct: Jacksonville

KEY MESSAGES

For the latest NE FL and SE GA Daily Key Messages please visit: https:/www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf

- Flood Watch through Monday Evening for locations west of I-75

- Numerous TStorms this Weekend through Early Next Week. Strong Storm Potential Each Afternoon and Evening. Daily Rounds of Heavy Downpours May Cause Localized Flooding

- Moderate Rip Current Risk at Area Beaches on Sunday

UPDATE

A Flood Watch was issued with the update this morning. The Flood Watch is in effect through Monday Evening for locations west of the I-75 corridor. Southwesterly flow will continue through the weekend, bringing tropical moisture into the area. Waves of numerous showers and thunderstorms are expected through the weekend, with rainfall totals between 1 and 3 inches, possibly higher amounts in localized spots, for those locations within the Flood Watch.

NEAR TERM /THROUGH TONIGHT/

Main Highlights For Tonight:

- Rounds of Showers and Thunderstorms, Isolated Strong Storms Possible

- Locally Heavy rainfall and flooding Possible, mainly for I-75 corridor

The weak frontal boundary currently just north of the Altamaha river will gradually lift northward today as a warm front ahead of a stronger cold front moving into the SE US. WSW flow strengthens this morning advecting in a more tropical airmass with PWATs of 2+ inches. This will ignite nocturnal convection over Apalachee Bay and the NE Gulf which will shift onshore during the predawn hours potentially progressing into the Suwannee Valley and I-75 corridor by sunrise. Convection then increases through the day and spreads ENE across NE FL and SE GA later this afternoon into evening. A cluster of upper level disturbances move in from the NW this afternoon and linger over the area tonight allowing for activity to continue well into the night and potentially into Sunday morning. With anomalously high PWATs, ample instability and support from the approaching upper impulses, numerous showers and thunderstorms this afternoon and evening could produce localized flash flooding with a few thunderstorms producing gusty winds of 40-55 mph. WPC has highlighted the I-75 corridor in a Slight (level 2 of 4) Risk for Excessive Rainfall and a Marginal (level 1 of 4) for the rest of the area for today. Highs will be slightly lower than yesterday in the upper 80s along the I-75 corridor to the low 90s elsewhere. Overnight lows remain in the 70s.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/

Main Highlights This Period:

- Rounds of Showers and Thunderstorms, Isolated Strong to Severe Storms Possible

- Locally Heavy rainfall potential into Monday

Sunday, the trough will move towards the southern Appalachians into Sunday night, becoming elongated north to south as Atlantic ridge begins to build westward towards the Atlantic waters off the southeast US coast. This will slow the surface front across the deep south just northwest of our area. The squeeze between the two mid to upper level features will yield increasing low level SW flow and tap higher moisture levels into the area with PWATs surging to near daily records of 2.20-2.40 inches. The high moisture, lift and instability ahead of the front will lead to widespread showers and thunderstorms focused over the western half of inland NE FL shifting north and eastward into SE GA and the coast through the afternoon hours.

Isolated strong to severe storms will develop where storm outflows and cell mergers interact. Widespread totals Sunday of 1 to 3 inches of rain will fall west of I-75 with less rainfall towards the coast, but locally heavier rainfall amounts will be possible with any slow moving or training cells (successive storms moving over the same area) which could lead to flooding in low lying and urban locations. The Weather Prediction Center has a slight risk over the Suwannee Valley of NE FL and a Marginal risk to the the rest of NE FL and SE GA. Breezy SW winds 10-15 mph will prevail Sunday with gusts to 20- 25 mph ahead of storms while more intense storms could produce gusts 40-60 mph.

Sunday's highs will be below normal due to mostly cloudy skies showers and storms, only reaching the mid to upper 80s inland to near 90 at the coast and I-95. Lows will be in the lower 70s inland and the mid 70s along the coast. Monday, the shortwave trough to the north will begin to become a closed, cut off trough across the southern Appalachian mountains While Atlantic high pressure ridging aloft builds into the Bahamas. Breezy south to southwest winds will once again prevail 10-15 mph gusting to 25 mph. Shortwave energy from the trough and convergence along the Gulf and Atlantic seabreezes will lead to numerous to widespread thunderstorms in the afternoon. Isolated strong to severe storms

Highs will be similar Monday in the upper 80s for NE FL and near 90 across SE GA and the coast.

LONG TERM /TUESDAY THROUGH FRIDAY/

Main Highlights This Period:

- Decreasing Coverage of Thunderstorms by Midweek

Tuesday, the closed mid to upper level trough will slowly lift away to the NNE as Atlantic ridging moves across the south and central FL peninsula. This will create a more typical Seabreeze regime of afternoon thunderstorms from Seabreeze interactions with scattered to numerous storms. The SW flow will decrease with Seabreezes merging near US-17 in the afternoon with southeast winds behind the Atlantic seabreeze.

Wednesday into Thursday, Atlantic high pressure surface ridge axis will lift into SE GA with flow prevailing from the southeast and favoring a more inland progressing Atlantic seabreeze with scattered afternoon thunderstorms with Gulf/Atlantic seabreezes merging between highway 301 and I-75.

Friday, the ridge axis will lift north of the area with easterly flow prevailing across the region and scattered T'storms developing well inland near I-75

Temperatures will begin with highs a little below normal Monday and near normal Tuesday, then inland highs will be above normal Wednesday into Friday with near normal coastal highs in the upper 80s to low 80s due to the onshore southeast to easterly flow. Lows will remain near normal with lows trending above normal in the low 70s inland and mid 70s at the coast with coastal lows warming to the upper 70s by Thursday.

AVIATION /12Z SATURDAY THROUGH 12Z SUNDAY/

Light generally southwesterly winds continue this morning hours, increasing around 10 kts by 18Z outside of SHRA and TSRA. Southerly winds develop at the coastal TAF sites after 16Z with the pinned Atlantic sea breeze. Waves of showers and storms will continue to move in from the west-southwest near GNV spreading to the rest of the TAF sites between 17-23Z. Have TEMPOs for stronger storms capable of gusty winds and lower VSBYs due to heavy rainfall.

MARINE

A frontal boundary will remain nearly stationary over the Georgia waters today, while high pressure remains situated over the southeastern Gulf. This weather pattern will create a prevailing offshore wind flow, with the afternoon sea breeze shifting winds to southerly in the afternoon and then back to southwesterly overnight. Coverage of mainly afternoon and evening thunderstorms will increase this weekend and early next week as the frontal boundary over the Georgia waters lifts northward as a warm front ahead of another cold front that will be entering the southeastern states. Southwesterly winds will strengthen ahead of this front beginning Sunday morning, with Caution level wind speeds likely and periods of Small Craft Advisory conditions possible through early Monday. Strong storms will be possible each afternoon and evening through Tuesday.

Rip Currents: Prevailing offshore winds this weekend through Monday will likely yield a low to low-end moderate risk at area beaches.

FIRE WEATHER

- Isolated Strong to Severe Storms Possible This Weekend

An active pattern will persists today the frontal boundary remains nearly stationary across Southeast Georgia. Southwesterly winds will become breezy 10-15 mph gusting to 20 mph across NE FL with winds a bit less over SE GA 8-12 mph, becoming southeasterly at the coast behind the afternoon Atlantic seabreeze 10-15 mph gusting to 20 mph. A wave of energy aloft and lift along the front and seabreezes will create Numerous showers and thunderstorms in the afternoon hours. The front will lift away as another front approaches from the northwest Sunday and then stall Monday just northwest of the area with numerous to widespread afternoon showers and thunderstorms each day and breezy southwest winds. Locally heavy rainfall is possible this weekend into early next week with widespread rainfall amounts of 3-5 inches west of I-75 and 1-2 inches towards the coast with locally heavier totals possible.

Dispersions will be in the good range through the weekend as surface and transport winds increase slightly by Sunday while clouds increase and limit mixing heights.

Fog Potential: Significant fog development is not expected during the next several mornings. Isolated strong to severe thunderstorms are possible into the weekend with gusty winds up to 40-60 mph in thunderstorms. In addition, outflows from distant thunderstorms may also produce gusty and erratic winds.

PRELIMINARY POINT TEMPS/POPS

AMG 92 73 89 73 / 90 50 80 60 SSI 91 76 91 75 / 90 40 80 40 JAX 92 73 89 73 / 60 30 80 30 SGJ 91 74 88 74 / 80 30 70 30 GNV 90 72 85 72 / 80 60 80 60 OCF 90 73 85 73 / 80 60 80 50

JAX WATCHES/WARNINGS/ADVISORIES

FL...Flood Watch through Monday evening for FLZ021-035-236-340-522. GA...None. MARINE...Small Craft Advisory from 2 PM Sunday to 8 AM EDT Monday for AMZ450-452-470-472.