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

- Moderate Rip Current Risk at Area Beaches through Thursday

- Isolated Thunderstorms possible Sunday into Sunday Night

- Low Potential for Freezing Rain Sunday & Sunday Night across Southeast GA

- Small Craft Advisory is Possible Across Coastal Waters from Saturday through early next week

- Widespread Freeze likely Tuesday morning and Wednesday morning next

- Severe Drought Conditions Expanding across our Region

NEAR TERM /THROUGH TONIGHT/

A persistent but weakening surface high pressure ridging will remain over the GA and SC area rest of today into tonight. Meanwhile, an offshore inverted surface trough, noted in latest NWP guidance and ASCAT imagery, has developed and is keeping the immediate coastal areas under mostly north to northeast flow at about 8-15 mph while inland areas will be more easterly. The northeast flow is shallow with NAM soundings and JAX VWP showing a southeast wind at about 2000 ft. With the prevailing dry airmass in the low levels, conditions remain dry. A mid to upper level disturbance will move across the southeast states through tonight and will continue the advection of mid to high clouds across the areas rest of the today into tonight while thickening clouds anticipated. A warming trend today with highs warming into the 60s to around 70, warmest over the south zones where more sun is noted. The warming trend continues into tonight with lows, not as cold as last night, in the min temps in the 40s, but around 50 or lower 50s close to the coast and over parts of St Johns and Flagler counties. There is some low potential for patchy fog after midnight, given some light moisture advection in the lowest levels and model soundings, and so have continued to advertise patchy fog for eastern zones.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

High pressure continues to weaken and shift northeast of the region Thursday and into Friday as a cold front approaches from the northwest, though stalling just north of the region Thursday Night and through Friday as the flow aloft become nearly parallel to the boundary. A few showers cannot be ruled out ahead of the front Friday Evening over interior GA, but otherwise expecting generally fair weather to prevail during most of the short term period. The weakening flow and warming temps in the boundary layer will also result in a general warming trend through the short term, with above normal highs expected both Thursday and Friday. Generally low to mid 70s expected Thursday except for some mid to upper 60s near the coast, followed by mid to upper 70s inland and upper 60s to low 70s by the coast on Friday. Friday Night, the front starts to drop further south and east across the area as strong high pressure builds behind it and towards the region come Saturday Morning. Similarly, there is about a 10-15% chance of showers across southeast GA and towards I-10 associated with the boundary, though significant rainfall chances/PoPs are expected to hold off until after the short term period. Lows in the 40s and 50s will be expected each morning, with 50s making their way further north and west for Saturday Morning due to more cloud cover expected despite some weak cold air advection. Uptick in low level moisture for the next few days will also return fog potential for both Friday and Saturday Morning, especially Friday Morning as surface winds are expected to be lighter compared to Saturday when the flow starts to increase with the front.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Tricky forecast for the weekend and into Monday as a complex and significant storm system takes shape across the southern Plains and parts of the southeast US.

As mentioned above, a frontal boundary does look to settle near or just south of the area on Saturday as cold high pressure tries to make a push southward towards our region. This airmass will struggle to make it significantly south however due to the zonal flow aloft. A few showers will be possible during the day on Saturday as a shortwave moves across the zonal flow, mainly north of I-10. The forecast gets tricker for Sunday and into Monday as surface high pressure starts to shift more north or northeast of the area and the aforementioned cold front lifts northward as a warm front. Guidance is in good agreement with respect to a cold air damming type of surface setup as surface ridging tries to hang tough down the eastern seaboard and towards our area. However, the main question is with respect to the magnitude of the low level cold air in place, and how much it "hangs on" for northern portions of the region as the front lifts northwards as a warm front and surface low pressure tries to form off the coast of the Carolinas. Trends in guidance have generally been supporting more of a warm sector type of setup on Sunday and Sunday Night, with enough warm air advection across the area to keep the colder surface temps and drainage flow confined well north of the area. However, if a more southern shift occurs with this colder air at the very low levels over the coming days, then this could increase chances for freezing rain across portions of well inland southeast GA. However, at this time, freezing rain chances are only about 5-10% for areas north and west of US84 in GA. With both and warmer and more moist trend late this weekend and into early Monday, this also would introduce the thunderstorm potential out ahead of the trailing cold front, mainly on Sunday Evening and into the first part of Sunday Night. Main focus area would be the Upper Suwannee Valley and towards I-75 in FL where the highest moisture would be from the Gulf. Severe activity looks low at this time, though will monitor this potential over the coming days.

Low pressure forming along the clash of airmasses lifts north and east away from the region late Sunday Night and through monday, progressing a cold front through the area fully on Monday with the return of more cool and dry air after a very warm several days for most of the area. Cool and dry high pressure looks to stick around for both Monday and Tuesday before some moderation is possible by midweek and the surface high shifts towards northeast of the region.

Higher than normal uncertainty as well as a roller coaster ride with respect to temperatures, depending on the exact setup and "battleground" between warm air advection to the south and the cold surge from the north. Above normal to well above normal temps appearing more likely for at least northeast FL for the weekend, trending closer to normal to possibly even below normal the further north you go this weekend. Consensus is stronger for below normal temps Monday through Wednesday.

AVIATION /18Z WEDNESDAY THROUGH 18Z THURSDAY/

VFR conditions will prevail at the regional terminals through Thursday 18z. Periods of broken high cloud cover will continue through this evening with more prevailing broken and then mid level clouds down to 8-10 kft on Thursday. There may also be some lower level clouds around 3-6 kft by early Thursday. Some of the forecast guidance shows a slight potential for IFR cigs around SGJ, VQQ, and CRG 08z-14z, but confidence is low. A northeast wind flow expected coastal terminals this afternoon around 8-12 knots, and northeast to easterly for more inland sites. Surface winds will then diminish after 00Z at the inland terminals, while winds shift to northerly around 5 knots at the coastal terminals. Light northeast flow anticipated on Thursday.

MARINE

High pressure ridge centered along the Mid-Atlantic coast will push offshore today, with this feature extending its axis southwest along the southeastern seaboard through Friday. Breezy northeasterly winds will gradually diminish by this evening. A developing winter storm system over the central and southern United States late this week and Arctic high pressure building to the north of our region will drive a cold front south across our waters on Friday night and Saturday, with a surge of northeast winds expected to overspread our local waters from north to south early this weekend. A wave of low pressure then develops along this boundary near our region by Saturday night and Sunday. This storm system's warm front will lift northeast across our local waters on Sunday. Another cold front will cross our local waters by Sunday night and Monday, with strengthening north winds forecast in the wake of this frontal passage early next week.

Rip Currents: SE GA Low/Moderate risk through Thursday. NE FL Moderate risk through Thursday

FIRE WEATHER

High pressure weakens while slowly shifting further north and east of the region through Thursday. This will allow a northeasterly onshore flow to subside, but also result in areas of low dispersions for both today and Thursday. Weak high pressure will remain across the area through at least Saturday Morning before a frontal system approaches and slowly moves through the area Sunday and Sunday Night, possibly into Monday Morning. This will bring milder and more humid conditions to most or all of the area this weekend as well as chances for showers and perhaps an isolated thunderstorm. Cooler and drier airmass moves back in for early next week as the associated cold front moves through the region.

FOG POTENTIAL AND OTHER REMARKS: Patchy fog will be possible early Thursday morning and Friday morning, mainly inland.

PRELIMINARY POINT TEMPS/POPS

AMG 42 72 46 72 / 0 0 0 10 SSI 49 65 51 67 / 0 0 0 0 JAX 47 72 49 76 / 0 0 0 0 SGJ 52 70 54 74 / 0 0 0 0 GNV 49 77 51 80 / 0 0 0 0 OCF 49 76 51 80 / 0 0 0 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...None. GA...None. MARINE...None.