Marine Weather and Tide Forecast for St. Augustine Beach, FL

NEAR TERM /THROUGH TUESDAY/

Cold, dry air advection is ongoing early this morning across the entirety of the area as a cold front continues to push south of the region. Winds have overall been slightly lower than guidance, especially over land though expecting more of a surge over the next several hours closer to the coast as winds here turn more north to north/northeasterly. Wind advisory remains in effect for coastal northeast FL for this same reason, as expecting gusts around 40mph to become more frequent after about within the few hours and continue through about mid morning. Further north and west of the coast and St. Johns River, northwest to northerly breezes around 10- 15 mph will be expected through the same time frame with gusts to around 25-30 mph at times. Have bumped up low temps just a few degrees based on latest trends, though still expecting widespread 20s and low 30s over southeast GA and north and west of about HWY 301 in northeast FL, with 40s more common south and east closer to the St. Johns River. Freeze Warning remains in effect for most areas of the interior as well as a Cold Weather Advisory with wind chills under 25 degrees expected. Although a more areas within the Freeze Warning may not reach a freeze criteria (like parts of Alachua, Bradford, and Clay Counties), dangerously cold wind chills are still very much expected.

For the rest of Monday, it will be a cold and dry one as arctic high pressure ridging starts to settle. A coastal trough developing overnight and during the morning hours will keep more clouds in the forecast for eastern areas and especially eastern areas over northeast FL through tonight and especially this evening, also helping to keep a stronger gradient in both wind speeds and dew points accordingly with a northeasterly onshore flow around 10-20 mph with gusts up to 25-30 mph. Rip current risk will be high at area beaches today with the breezy onshore flow and rough wave heights. The further north and west you go into interior GA closer to the high pressure center, much drier and lighter winds as dew points have the potential to drop below zero north and west of about Waycross. Temperatures in the 40s will be common north of about I- 10, and 50s to near 60 the further south of about I-10 you go.

Cloud cover coverage is expected to drop off a bit for eastern areas tonight, though a few low clouds will linger across much of the area with a cold night expected for most. Low temperatures tonight are a bit tricky, especially closer to the coast and St. Johns River Basin as it will depend on how strong the northeasterly flow stays overnight. The further inland you go, mostly prime radiational cooling conditions are expected with very light to calm winds, a very dry airmass, and only a few clouds. Temps in the low 20s will be common over interior GA, with upper 20s to low 30s over the upper Suwannee Valley and west of the St. Johns River. Expecting the cut off to be very sharp close to the St. Johns River and areas south and east as forecast lows will quickly jump into the 40s south and east of about HWY 301 in Florida.

SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/

Troughing aloft will shift offshore on Tuesday, with dry northwesterly flow continuing across the southeastern states. This flow will turn more zonal by Tuesday night, followed by west- southwesterly flow developing on Wednesday as ridging aloft over the Caribbean builds towards the FL peninsula. Meanwhile, Arctic high pressure will continue to weaken as it settles over the southeastern states on Tuesday, with this feature shifting offshore by Wednesday morning. Otherwise, a dry air mass and plenty of sunshine at inland locations will allow for a gradual moderation of temperatures, while a persistent coastal trough over the Atlantic waters adjacent to east central and northeast FL continues to funnel marine stratocumulus over coastal locations from St. Augustine southward, with these clouds extending into southern portions of the St. Johns River basin and north central FL as well. Highs will climb to the upper 50s on Tuesday afternoon for locations north of Waycross and for coastal locations from Fernandina Beach northward, with 60s elsewhere, except around 70 in north central FL.

Radiational cooling on Tuesday night will drop lows down to the mid 30s across inland portions of southeast GA, where areas of frost formation are likely. Lows elsewhere at inland locations will range from the upper 30s to the mid 40s, with patchy fog formation possible across inland portions of northeast and north central FL during the predawn and early morning hours. A light northerly breeze and marine stratocumulus will keep coastal lows in the upper 40s and lower 50s. Multi-layered cloudiness will overspread our area on Wednesday as low level flow veers, driving marine stratocumulus onshore and inland by the afternoon hours, while shortwave energy embedded in the developing west-southwesterly flow pattern aloft results in increasing higher altitude cloud cover. Warm air advection will counter this increasing cloud cover, allowing highs to rebound to the mid to upper 60s across southeast GA and coastal northeast FL, while inland areas of northeast and north central FL reach the 70-75 degree range. Warm air advection will allow lows to continue to modify, with mid to upper 40s for inland southeast GA and northern portions of the Suwannee Valley, ranging to the 50s elsewhere. Patchy fog and low stratus cloud formation will be possible towards sunrise on Thursday.

LONG TERM /THURSDAY THROUGH MONDAY/

Troughing will dive southeastward from the northern Rockies on Wednesday night though the Plains states and Upper Midwest on Thursday. This trough will then pivot eastward across the Great Lakes region and the Ohio and Tennessee Valleys on Thursday and Thursday night. This trough will drive a weakening cold front into the southeastern states on Thursday night, allowing southwesterly flow to deepen over our region. PWAT values will increase to around 1.5 inches across our area by Thursday afternoon and evening, likely allowing for a few showers to develop across our region from late Thursday afternoon through Thursday night, with widely scattered coverage possible for locations north of Waycross ahead of the approaching frontal boundary on Thursday night. The bigger story will be the continued rise in temperatures, as highs climb into the 70s at most locations on Thursday afternoon, except upper 60s for coastal southeast GA. Lows on Thursday night will remain in the 50s area-wide.

Troughing aloft will take on a more negative tilt late this week as it swings through New England, with this feature pushing a weakening cold front across our area later on Thursday night and Friday. High pressure building over the southern Plains and Texas in the wake of this frontal passage on Thursday night will expand across the lower Mississippi and Tennessee Valleys on Friday, reaching the southern Appalachians and the Ohio Valley by Friday evening. A drier air mass will overspread our region on Friday and Saturday in the wake of this frontal passage, with cool air advection dropping highs to the mid and upper 60s across southeast GA and portions of coastal northeast FL, while 70s persist elsewhere. Decoupling winds at inland locations on Friday evening should allow lows to fall to the upper 30s for inland southeast GA, with 40s elsewhere, except 50s along the northeast FL coast, where a light northeasterly breeze will develop overnight.

High pressure will then push offshore of the Delmarva peninsula on Saturday night, allowing low level winds to again veer, signaling another period of warm air advection across our region during the weekend. West-southwesterly flow aloft will also redevelop as ridging aloft over the Caribbean Sea attempts to build back towards the FL peninsula. Onshore winds will keep coastal highs in the upper 60s to around 70 on Saturday, with 70s forecast elsewhere, except upper 60s for locations north of Waycross in southeast GA. Lows will moderate on Saturday night, with upper 40s forecast for inland southeast GA and northern portions of the Suwannee Valley, while 50s prevail elsewhere. Highs on Sunday will climb into the 70s area- wide, except around 80 for north central FL. Lows on Sunday night will remain in the 50s area-wide.

AVIATION /00Z TUESDAY THROUGH 00Z WEDNESDAY/

Low stratocumulus clouds at MVFR category look to continue most of the night and have pushed back any improvement until Tuesday morning and even then it looks like areas to widespread MVFR may be lingering over the area. The guidance shows much lower MVFR chances by 07z-12z, but that looks very questionable. Looked at the IFR probabilities and these area fairly low and have not seen any reports of IFR so no TEMPO groups look needed for that. However, showed SCT decks for JAX, VQQ, and GNV at about 800 ft later tonight. Isolated shower activity associated with a sfc trough offshore look to stay east of SGJ through Tuesday. For sfc winds, mainly north- northeast about 6-12 kts through Tuesday. Should be lighter winds around the 04z-12z time frame.

MARINE

Arctic high pressure centered over the Ohio and Tennessee Valleys will gradually weaken as it shifts southward towards our region tonight. Meanwhile, coastal troughing will take shape over the northeast Florida waters this afternoon and tonight.
Seas will remain at Small Craft Advisory levels for the offshore waters through Tuesday morning. Winds will shift to southerly and then southwesterly on Thursday and Thursday night ahead of a weakening frontal boundary that will approach our local waters, bringing widely scattered showers and possibly a few thunderstorms, mainly offshore. This frontal boundary will cross our area on Friday morning, shifting winds to northwesterly during the afternoon hours. High pressure building north of our region on Friday afternoon and evening will wedge down the southeastern seaboard, resulting in winds shifting to northeasterly by Friday night and then easterly on Saturday afternoon.

Rip Currents: SE GA Moderate Tuesday NE FL Moderate Tuesday

FIRE WEATHER

Arctic high pressure will settle over the southeastern states this afternoon, funneling a cold and very dry air mass into our region.
Following a widespread hard freeze this morning, long durations of critically low humidity values are forecast this afternoon for inland southeast Georgia. Breezy northeasterly surface and transport winds across southeast Georgia this morning will gradually diminish this afternoon, precluding Red Flag conditions. Breezy to strong northeasterly surface and transport winds will continue today for coastal locations and for inland locations south of Interstate 10, yielding good daytime dispersion values. Fair values are expected elsewhere.

Surface and transport winds will become light and variable across southeast Georgia and northern portions of the Suwannee Valley on Tuesday, where low daytime dispersion values are expected.
Northeasterly surface and transport winds will continue to diminish along the I-10 corridor, where poor daytime dispersion values are forecast. Breezy transport winds across north central Florida will yield fair to good dispersion values on Tuesday. Surface and transport winds will shift to easterly by Wednesday morning and then southeasterly by the afternoon hours, except southerly across inland portions of southeast Georgia. Light speeds will result in low daytime dispersion values for locations north of Waycross, with cloud cover increasing at coastal locations also creating low values. Poor values are expected elsewhere, except fair values across north central Florida.

FOG POTENTIAL AND OTHER REMARKS: Freeze warnings are in effect early this morning for all of southeast Georgia, the Suwannee Valley, and for locations west of Interstate 95 in northeast Florida. A Freeze Watch is in effect for these same locations tonight through early Tuesday morning, with widespread frost formation likely as winds decrease this evening and overnight. Patchy to areas of fog formation will be possible for inland portions of northeast and north central Florida during the predawn and early morning hours on Wednesday. Patchy to areas of frost formation will be possible across inland portions of southeast Georgia on Tuesday night and early Wednesday morning.

PRELIMINARY POINT TEMPS/POPS
AMG 25 58 34 65 / 0 0 0 0 SSI 37 59 47 64 / 0 0 0 10 JAX 35 63 44 70 / 0 0 0 0 SGJ 48 65 52 71 / 0 0 0 10 GNV 38 68 46 74 / 0 0 0 0 OCF 40 69 48 75 / 0 0 0 0

JAX WATCHES/WARNINGS/ADVISORIES
FL...Freeze Warning until 9 AM EST Tuesday for FLZ021-023-024-030- 120-220-322-422-522.
High Risk for Rip Currents until 10 PM EST this evening for FLZ124- 125-138-233-333.
High Surf Advisory until 7 PM EST this evening for FLZ138-233- 333.
GA...Freeze Warning until 9 AM EST Tuesday for GAZ132>136-149- 151>154-162-163-165-166-250-264-350-364.
High Risk for Rip Currents until 10 PM EST this evening for GAZ154- 166.
MARINE...Small Craft Advisory until 7 PM EST this evening for AMZ450.
Small Craft Advisory until 1 AM EST Tuesday for AMZ452-454-470.
Small Craft Advisory until 10 AM EST Tuesday for AMZ472-474.