Marine Weather Net

Surf City to Cape Fear, NC out 20 NM Marine Forecast


TONIGHT

SW
WINDS
15 - 20
KNOTS

FRI

SW
WINDS
10 - 15
KNOTS

FRI NIGHT

SW
WINDS
15 - 20
KNOTS

SAT

SW
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
AMZ250 Forecast Issued: 645 PM EDT Thu Jul 18 2019

Tonight...Sw Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 4 To 5 Ft. Isolated Showers And Tstms Overnight.
Fri...Sw Winds 10 To 15 Kt, Increasing To 15 To 20 Kt In The Afternoon. Seas 3 To 4 Ft. Scattered Showers And Tstms, Mainly In The Morning.
Fri Night...Sw Winds 15 To 20 Kt, Diminishing To 10 To 15 Kt After Midnight. Seas 3 To 4 Ft. A Chance Of Showers And Tstms.
Sat...Sw Winds 10 To 15 Kt. Seas 3 Ft. A Chance Of Showers And Tstms.
Sat Night...Sw Winds 10 To 15 Kt. Seas 3 To 4 Ft. A Chance Of Showers And Tstms.
Sun...Sw Winds 15 To 20 Kt. Seas 3 Ft. A Chance Of Showers And Tstms Through The Night.
Mon...Sw Winds 15 To 20 Kt. Seas 3 To 4 Ft. A Chance Of Showers And Tstms.
Tue...Sw Winds 10 To 15 Kt, Diminishing To 10 Kt. Seas 3 To 4 Ft. A Chance Of Showers And Tstms Through The Day, Then Showers And Tstms Likely Through The Night. Winds And Seas Higher In And Near Tstms.
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Area Forecast Discussion
National Weather Service Wilmington NC
729pm EDT Thu July 18 2019

Synopsis: Hot and humid weather with dangerous heat index values will continue through the weekend and into early next week. A cold front should push across the Carolinas late Tuesday or early Wednesday, breaking the string of hot and humid days.

Near Term - Through Friday Night
As of 700pm Thursday...Clusters of strong thunderstorms continue to affect the central and eastern Carolinas this evening as a weak mid level trough provides enough enough lift to unleash surface-based CAPE of 3000 J/kg. Winds aloft are modest so storm organization has been limited to loose multicell clusters. Massed cold pools behind the storms have produced forward-propagating linear features with strong wind gusts the primary threat. With such warm air aloft (freezing levels near 14000 feet) it's unlikely hail will be a significant threat. HREF ensembles and recent HRRR runs indicate convection should gradually diminish this evening, with only an isolated shower or storm possible by midnight along the coast or offshore. Forecast PoPs have been adjusted accordingly to focus on the cluster of storms sweeping into Williamsburg County from the west, and on the line of showers and storms along the seabreeze/outflow interaction from Myrtle Beach to Whiteville.

Where heavy rain occurred earlier (like Marion, SC) temperatures have already popped below forecast lows tonight. Once convection dissipates, a moderate-strength southwest low level jet should redevelop and keep the boundary layer reasonably well mixed overnight. Although not quite as warm overall as last night, I do think coastal and urban locations near Cape Fear have a good potential of seeing another night of 80+ degree lows. Wilmington has already had one such hot night this year (July 12) and may ring up a second one if temps remain 80 or higher through midnight tonight. A third may occur tomorrow if big storms avoid the city.

Inland lows should generally fall to 75-78 degrees.

Other changes to the forecast were generally minor. Discussion from 300pm follows... Heat advisory conditions expected again on Friday as high heat and humidity combine to produce dangerous heat with heat indices up over 105. A few places will near Excessive Heat Warning criteria of 110 or higher. Temps will reach into the mid 90s most places once again Fri with overnight lows between 75 and 80 both tonight and Fri night. The westerly downslope flow in the lower levels should add to heat potential on Fri, but should see more clouds around to help balance it out a bit.

Mid level trough will shift slowly eastward trying to make its way across the Carolinas tonight through Friday. This trough approaching from west will help to enhance convective development in an already unstable atmosphere. All models point at a late day spike in convection inland with activity diminishing as it moves toward the coast closer to midnight. Therefore best chance of greater storm coverage will be I-95 corridor late afternoon and shifting toward the coast in a westerly steering flow, but diminishing later this evening into early overnight hour as we lose heating.

The mid level trough will remain aligned from SW to NE over the Carolinas as it eases slightly eastward overnight into Fri. This should help to maintain greater cloud cover and convective activity with slightly higher SW winds through Fri. This trough is coming up against ridge over the Atlantic, though which should re-exert itself, especially heading into the weekend. Depending on how quickly, should end up with limited, if any activity heading into overnight Fri, but another hot and humid day expected on Fri

Short Term - Saturday Through Saturday Night
As of 300pm Thursday...The latest guidance has trended drier for Saturday but looking at model soundings profiles are similar to previous days so I have maintained the chance probability of precipitation area wide. Not a lot of forcing is probably what guidance is keying on but the sea breeze boundary and outflows should be enough. Almost impossible to go with a dry forecast this time of year. HIghs in the lower to middle 90s combined with the dewpoints well into the 70s will most likely warrant another heat advisory

Long Term - Sunday Through Thursday
As of 300pm Thursday...The main focus of the extended will be on the events of the latter part of the period as guidance still points to a decent mid level trough developing and or moving across the Eastern U.S. Of course there is the usual wobbling of the front and its final position but it will likely be in the area enhancing convection. The overall trend of the forecast remains intact, cooling temperatures with increasing pops

.AVIATION /00Z FRIDAY THROUGH TUESDAY/... As of 23z...Expecting convection near KCRE/KMYR to gradually diminish through 02Z. In addition the air-mass near KFLO has stabilized, however conditions could support TSRA a little longer into the evening in the vicinity of KLBT where the air- mass has not been worked over. Regardless, coverage will diminish all areas over the next few hours with the loss of heating. As a result, VFR CIGs/VSBYs will dominate this TAF period overnight through Friday morning. Additional convection Friday afternoon could lead to TEMPO MVFR conditions but not enough confidence at this time to include other than VCTS.

Extended Outlook...VFR conditions are expected outside any isolated to widely scattered convection through Monday, with increased chances of rain Tuesday

Marine Discussion
As of 700pm Thursday...Thunderstorms late this afternoon affected the waters north of Wrightsville Beach. Now that the storms are gone southwest winds are redeveloping across the this area with speeds similar to that being observed south toward Cape Fear and the Grand Strand area: 15-20 kt. These winds should largely continue overnight, maintaining a choppy 5-second dominant wave period with sea heigheights in the 4-5 foot range. This is just shy of Small Craft Advisory thresholds.

Thunderstorms in the Myrtle Beach area now at 7pm should weaken as they move across the beaches, but outflow winds from these storms will create a couple hours of unsteady offshore wind directions. Models suggest only scattered showers or thunderstorms may redevelop overnight, perhaps organization late tonight along any landbreeze fronts that might develop off the South Carolina coast. Discussion from 300pm follows... Gusty SW winds will continue into tonight in tightened gradient between trough inland and Bermuda High. Gusts up to 20-25 kts will continue in sea breeze and enhanced troughing through tonight, but should diminish heading through Fri into the weekend with a spike up in the afternoon sea breeze again. The southerly push will keep seas up between 3 and 5 ft overnight but seas should come down to 2 to 4 ft late Fri into Sat.

Winds and seas basically a persistence forecast for the short term and much of the extended. Southwest winds of 10-15 knots will continue with significant seas of 2-4 feet. Some uncertainty in the wind directions show up toward the end of the period as a front attempts to cross the area. Wind directions become basically erratic as is typical with a decaying front but speeds with this feature (also typical) will be very light

NOAA Wilmington NC Office: Watches - Warnings - Advisories
SC...Heat Advisory from 11am to 7pm EDT Friday for SCZ017-023-024- 032-033-039-054>056-058-059.
Beach Hazards Statement until 8pm EDT this evening for SCZ054- 056. NC...Heat Advisory from 11am to 7pm EDT Friday for NCZ087-096-099- 105>110.
Beach Hazards Statement until 8pm EDT this evening for NCZ106- 108. MARINE...None.