Apalachee Bay and Coastal Waters From Keaton Beach to Ochlockonee River FL out 20 NM Marine Forecast
|Rest Of Today...West Winds 5 To 10 Knots Becoming North Late In The Afternoon. Seas 1 Foot Or Less. Dominant Period 3 Seconds. Protected Waters Mostly Smooth. Chance Of Showers.|
|Tonight...Northeast Winds 10 Knots. Seas 1 To 2 Feet. Dominant Period 2 Seconds. Protected Waters A Light Chop. Slight Chance Of Showers After Midnight.|
|Sunday...East Winds 10 Knots Becoming South 10 To 15 Knots In The Afternoon. Seas 1 To 2 Feet. Dominant Period 2 Seconds. Protected Waters A Light Chop. Slight Chance Of Showers And Thunderstorms In The Morning, Then Chance Of Showers And Thunderstorms In The Afternoon.|
|Sunday Night...Southwest Winds 15 To 20 Knots. Seas 2 To 3 Feet. Dominant Period 4 Seconds. Protected Waters Choppy. Chance Of Showers And Thunderstorms In The Evening, Then Showers And Slight Chance Of Thunderstorms After Midnight.|
|Monday...Northwest Winds 15 To 20 Knots. Seas 2 To 4 Feet. Dominant Period 4 Seconds. Protected Waters Choppy. Chance Of Showers And Slight Chance Of Thunderstorms In The Morning.|
|Monday Night...Northwest Winds 20 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet Subsiding To 2 To 3 Feet After Midnight. Protected Waters Choppy.|
|Tuesday...Northwest Winds 15 Knots. Seas 2 To 3 Feet. Protected Waters A Moderate Chop.|
|Tuesday Night...North Winds 10 To 15 Knots. Seas 1 To 2 Feet. Protected Waters A Light Chop.|
|Wednesday...Northeast Winds 10 Knots. Seas 1 To 2 Feet. Protected Waters A Light Chop.|
| Synopsis for the Suwannee River to Okaloosa-Walton County Line out to 60 nm - GMZ700|
1006 AM EST Sat Nov 28 2020
Southerly winds are expected to increase to advisory levels on Sunday, and continue to be elevated in the wake of a cold frontal passage Sunday Night into Tuesday. Seas will respond accordingly, peaking between 8 and 10 feet late Monday into early Tuesday over the offshore waters. Northwest winds may briefly gust to gale force during this time frame as well. A Small Craft Advisory is in effect starting Sunday afternoon. Winds and seas decrease late Tuesday into Wednesday, only to increase again late in the week in advance of the next cold front. Some sea smoke is also possible Tuesday or Wednesday morning as a much colder air mass moves over the relatively warmer gulf waters.
| Area Forecast Discussion|
National Weather Service Tallahassee FL
953am EST Sat Nov 28 2020
The cold front has pushed through all but portions of the Big Bend and south-central GA this morning. This front is expected to continue to push south and east through the remainder of today and stall south of our local waters late tonight. Will trim back PoPs for the remainder of today especially where the front has already passed. Some locations in the wake of the front may have already reached the expected max temp for today due to the widespread cloud cover.
.NEAR TERM [Through Saturday Night]... Cold front has entered our southeast Alabama counties with showers and isolated thunderstorms along and behind the front. Further east, patchy fog is occurring through the Florida panhandle into southern Georgia. Expect the rain to continue moving eastward as the front moves southeast with some isolated pockets of heavy rainfall. Lift begins to decrease towards mid morning as the front nears the western Florida Big Bend so an overall decrease in rain chances will occur towards the afternoon hours as the front makes it into the northeast Gulf. Drier air on northerly flow will advect in behind the front as the front stalls in the northern Gulf Saturday evening. Attention then turns upstream to a closed low moves into the southern Plains and a surface low develops on the stalled front in the western Gulf. Rain chances re-enter our western counties overnight Saturday night as overrunning showers develop north of the stalled boundary.
.SHORT TERM [Sunday through Sunday Night]... Some uncertainty remains in this portion of the forecast with regards to severe weather potential. The upper low moving over the Red River Valley Sunday will become absorbed in a southward moving shortwave trough moving down from the northern Plains. It will take on a negative tilt with plenty of diffluence overspreading the surface low pressure system. The surface low will move northeast into southern Louisiana/Mississippi Sunday afternoon and eastern Tennessee Sunday night. The stalled boundary to our south will move north as a warm front ahead of a strong cold front expected to move through much of our CWA Sunday night.
Wind profiles ahead of the system will strengthen with bulk shear values of 50-60 knots by late morning Sunday which is more than conducive to support severe weather. Area hodographs become long and curved depicting the increase in low level winds and good veering of the winds in the low levels. SRH values increase as well on the order of 300-600 m2s2 in the vicinity of the warm front. Forecasting the instability and the northward progression of the warm front and warm sector remains a challenge with spread between the deterministic and hires models. The GFS and a few hires models keep the instability more offshore whereas the NAM and ECMWF (European Centre for Medium-Range Weather Forecasts) more the warm front further northward and thus the instability further inland.
Damaging winds and isolated tornadoes are the main threats with this system. The tornado threat will be tied to the warm front and how far north the front will get and the extent of the warm sector. Damaging winds will mainly be tied to the cold front, although that threat will also accompany any supercells that can develop in the warm sector. With the uncertainty in mind, Storm Prediction Center continues the marginal risk through the area Sunday and Sunday night. However, if confidence grows in greater instability making it further inland, Storm Prediction Center may raise the threat level in later outlooks.
.LONG TERM [Monday through Saturday]... Monday and Monday Night:
The main story will be much colder temperatures in the wake of a cold frontal passage Monday morning, along with breezy conditions. A few residual showers are possible during the morning from the FL Big Bend into the I-75 corridor of Southwest GA, otherwise a dry day is on tap, with widespread stratocumulus below the low-level frontal inversion. Model soundings indicate the boundary layer extending to around 4k ft, under strong cold air advection, with 925 hPa temperatures falling 10-15 deg C throughout the day! Expect a slow rise in temperatures, only rebounding several degrees off morning lows, ranging from the mid-50s in Southeast AL to the mid-60s in the FL Big Bend. Given the aforementioned height of the boundary layer, momentum transfer should yield wind gusts in the 20-30 mph range out of the northwest. The combination of considerable cloudiness, below normal temperatures, and gusty winds will make for a chilly day!
The coldest night of the fall season is in store come Tuesday morning, with low temperatures forecast to range from the upper 20s in SE AL to the low-mid 30s in the FL Big Bend. Given the continued cold air advection, the boundary layer will likely not fully decouple, keeping the wind elevated Monday Night. This, along with Relative Humidity values well below saturation, is expected to preclude the development of a widespread frost.
Tuesday through Saturday:
This period will feature continued below average temperatures, with a shot at frost Wednesday morning, followed by the next chance of precipitation centered on Friday.
High pressure on the order of 1023 hPa will be centered in the Tri-State area Wednesday morning. This should promote light winds within a dry air mass. Relative Humidity values may fall short for a widespread frost, but certainly more sheltered locations will be susceptible, with low temperatures bottoming out in the upper 20s to lower 30s away from the gulf coast. It's worth noting that the average date of the first frost occurs in the first to second week of November away from the gulf coast. So far this year, we came close on Nov 3rd with low temperatures down to 35-36 F at ABY, DHN, and VLD, but the air mass was too dry to promote widespread frost (look for RH values close to 100 pct).
Looking ahead to the next system centered on Friday, there is considerable uncertainty, with little run to run consistency amongst the operational models and ensembles. Any impacts from this system will be largely determined on where the northern/ southern streams phase. The latest EC phases the streams over the lower plains, while the GFS is much farther east in the mid-Atlantic states. For now, it's too early to get into any specifics on heavy rain/severe weather potential. Rainfall is centered on late Thu into early Sat, with probability of precipitation increasing to 50 pct during this time frame, all of which will be refined much more as we draw nearer.
NOAA Tallahassee FL Office: Watches - Warnings - Advisories
FL...None. GA...None. AL...None. GM...Small Craft Advisory from 7pm Sunday to 1pm EST Tuesday for Apalachee Bay or Coastal Waters From Keaton Beach to Ochlockonee River FL out to 20 Nm-Coastal waters from Suwannee River to Keaton Beach FL out 20 NM.
Small Craft Advisory from 1pm EST /noon CST/ Sunday to 1pm EST /noon CST/ Tuesday for Coastal Waters From Ochlockonee River to Apalachicola Fl out to 20 Nm-Coastal waters from Mexico Beach to Apalachicola FL out 20 NM-Coastal waters from Mexico Beach to Okaloosa Walton County Line FL out 20 NM-Waters from Suwannee River to Apalachicola FL from 20 to 60 NM-Waters from Apalachicola to Mexico Beach FL from 20 to 60 NM-Waters from Mexico Beach to Okaloosa Walton County Line FL from 20 to 60 NM.