textproduct: NWS Wilmington

WHAT HAS CHANGED

Heat Advisories issued for the coastal southeast NC and coastal southeast SC counties for Friday. Updated aviation discussion with the issuance of the 18Z TAFS. Updated Key Message 1 and Marine section.

KEY MESSAGES

1) The heatwave with just isolated convection to dominate during the near term.

2) Relief from the heat is in sight with increasing coverage of showers and thunderstorms Sat night through Sunday night as a cold frontal system drops south across the area.

3) High risk of rip currents at south-facing beaches Friday and Saturday.

DISCUSSION

KEY MESSAGE 1...The heatwave with just isolated convection to dominate during the near term.

KEY MESSAGE 1 DESCRIPTION... The upper ridge axis across the area will keep a lid on the majority of any convection that tries to develop today. Isolated tstorms remain possible along the pinned sea breeze across coastal Northeast SC. Mid to upper 90s will dominate todays highs with 100+ degree readings still possible. Even the coastal locations will observe low to mid 90 degree readings. Some mixing of drier air aloft will result in upper 60s sfc dewpoints inland which will keep heat indices within the advisory criteria. However mid to upper 70s dewpoints will remain across the coastal counties which will result in HIs breaching Extreme Heat Warning thresholds.

A similar scenario will play out Friday and Saturday with a noted flattening of the upper ridge. Will still observe Heat Adv thresholds both Fri and Sat but max temps should remain below 100 degrees. This in part to an evolving increasing threat of convection Fri and especially Sat with debris cloudiness likely helping to hold down max temps. Increased convection chances Friday and Saturday could result in showers and thunderstorms that would limit the duration where heat indices reach 105+ degrees. Fairly confident for atleast a couple of hours of 105+ degree heat indices Friday. Thus, Heat Advisories have been issued for the coastal counties where peak HI could reach 105-109F Friday.

KEY MESSAGE 2...Relief from the heat is in sight with increasing coverage of showers and thunderstorms Sat night through Sunday night as a cold frontal system drops south across the area.

KEY MESSAGE 2 DESCRIPTION... An upper pattern change starting Sun will help aid in dropping a cold front southward, crossing the area Sun with high pressure slow to fill in from the north thru mid-week next week. The result will be the threat for numerous showers and tstorms late Sat night thru Sun night, even after the cold front drops south of the area. This pattern change involves the upper ridge that has plagued the east for quite some time, that will be shifting to the west-central part of the nation and progged to amplify considerably. With plenty of antecedent heat and moisture, the setup should be quite stormy Sunday and Monday, with some storms possibly on the strong/severe side. Temps will also drop considerably with residual low 90s Sun for highs followed by potentially 80s for highs early next week.

KEY MESSAGE 3...High risk of rip currents at south-facing beaches Friday and Saturday.

KEY MESSAGE 3 DESCRIPTION... Building southerly swell will lead to a high risk of rip currents for south-facing beaches Friday and Saturday. Continued hot weather and weekend timing will contribute to increased beach attendance - beachgoers should stay out of the water where a high risk of rip currents is in effect. Conditions improve on Sunday as the swell weakens, and currently a moderate rip risk is forecasted for Sunday for south-facing beaches.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

The 18z TAF period begins with VFR conditions in place. Overall thunderstorm chances this afternoon and evening look quite low, and we will handle any adjustments if anything develops with amendments. The sea breeze has already cleared through KMYR and KCRE, and has been timed into KILM at around 21z. A weak reflection of the sea breeze has been added into KFLO and KLBT in the evening after sunset. Overnight should be quiet and VFR and west winds will pick back up after sunrise tomorrow.

Extended Forecast...Generally VFR. Low potential for flight restrictions from fog or low ceilings each morning. Threat for periodic flight restrictions from daily afternoon and evening showers/thunderstorms through Sat. More numerous thunderstorms possible Sat night into Mon as a frontal system drops south across the region.

MARINE

Small Craft Advisories have been issued for all nearshore waters through tonight. A modest nocturnal surge will impact the waters with high pressure displaced well to the southeast. Frequent gusts to 25 kt appear likely so flags were raised to account for this. For Friday into Friday night, elevated winds will persist as the gradient between an inland trough tightens. Sustained winds of 20-25 kt with gusts nearing 30 kt appear likely. Given there will be a modest break on Friday in winds Friday morning and SCA for tonight was not extended into the day Friday. The need to extend the SCA through the day will be reevaluated later. Winds will diminish a bit for Saturday with relaxed gradient ahead of an approaching cold front. The front will push south Sunday with northeast winds prevailing Sunday night. A modest post frontal surge could push winds to near SCA levels from Cape Fear north.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Heat Advisory until 8 PM EDT this evening for NCZ087-096-099. Extreme Heat Warning until 8 PM EDT this evening for NCZ105>110. Heat Advisory from noon to 7 PM EDT Friday for NCZ105>110. Beach Hazards Statement until 8 PM EDT this evening for NCZ106- 108. SC...Heat Advisory until 8 PM EDT this evening for SCZ017-023-024- 032-033-039-059. Extreme Heat Warning until 8 PM EDT this evening for SCZ054>056-058. Heat Advisory from noon to 7 PM EDT Friday for SCZ054>056-058. Beach Hazards Statement until 8 PM EDT this evening for SCZ054- 056. MARINE...Small Craft Advisory until 6 AM EDT Friday for AMZ250-252-254- 256.