textproduct: NWS Wilmington

WHAT HAS CHANGED

Forecast high temperatures today and Monday have been increased by 1- 2 degrees, farther into record-breaking territory at Florence and Lumberton. Forecast thunderstorm chances Monday afternoon have been increased to 40-50 percent across the Cape Fear area.

KEY MESSAGES

1) Record heat in store for today away from the coast. Well above normal temperatures continue through Monday.

2) Scattered thunderstorms will accompany a cold frontal passage Monday afternoon. A few of the storms could become strong to severe.

3) Canadian high pressure building in from the north will bring two days of below normal temperatures Tuesday and Wednesday.

DISCUSSION

KEY MESSAGE 1: Record heat in store for today away from the coast. Well above normal temperatures continue through Monday.

Downslope flow along with 850 temps rising to 15-16C (few degrees above 90th percentile for this time of year) with produce record high temperatures for most of our area. Current forecast has highs around 90F this afternoon, with active sea breeze keeping coastal areas slightly cooler. 90F would surpass current record highs for FLO and LBT by three degrees (see current records for today and Monday below). Wind gusts this afternoon might end up being a bit higher than expected, up to 25 mph, which may temper the highs a couple of degrees (but still record warmth).

Low temps tonight will be well above normal in the low to mid 60s, about 15-20 degrees above normal. While highs Monday will be a few degrees lower than today, forecast still calls for temps to reach mid to upper 80s ahead of approaching cold front.

Record highs: ................... Sun Mar 22 ... Mon Mar 23 Wilmington NC......... 87 in 1907 ... 94 in 1907 Lumberton NC.......... 87 in 1948 ... 91 in 1907 N. Myrtle Beach SC.... 86 in 1995 ... 85 in 2011 Florence SC........... 87 in 1995 ... 88 in 1995

KEY MESSAGE 2: Scattered thunderstorms will accompany a cold frontal passage Monday afternoon. A few of the storms could become strong to severe.

As the cold front reaches southeastern North Carolina Monday afternoon there should be surface CAPE on the order of 500 J/kg inland to nearly 1000 J/kg near the coast. A seabreeze should have already have developed along the beaches, creating good low level convergence up against northerly winds behind the front. This could lead to an area of thunderstorms, sculpted into southeastward moving multicells by 35 kt of 0-6 km bulk shear. After collaboration with NWS MHX, I've bumped up forecast PoPs across the Cape Fear area to 40-50 percent Monday afternoon. Gusty winds may develop if dry air above 800 mb is entrained into convective downdrafts. SPC's Day 2 marginal risk addresses this potential.

KEY MESSAGE 3: Canadian high pressure building in from the north will bring two days of below normal temperatures Tuesday and Wednesday.

After several days of above normal and record-breaking temperatures, the Canadian airmass building in behind the front will feel particularly chilly. Forecast highs on Tuesday in the lower 60s are below normal and a good 22-26 degrees below Monday's forecast highs. Temperatures should recover into the 70s by Thursday and back into the 80s by Friday.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

Predominantly VFR, with spotty MVFR vsbys early this morning clearing quickly after sunrise. Light winds this morning become southwesterly during the day. Gusts may reach 20 kts this afternoon, especially at coastal terminals where sea breeze will be active as inland temperatures reach 90F. Boundary layer remains mixed tonight, keeping winds at 5-10 kts with gusts to 15 kts overnight. LLWS after 6/7z tonight through end of TAF period with 35-30 kt westerly winds at 2000 ft.

Extended Forecast...VFR to dominate. A cold front will move through on Monday with the chance for isolated restrictions due to t-storms. VFR then prevails through Thursday.

MARINE

Through Tonight...Southwesterly winds and seas increase during the day today. Winds 15-20 kts by this afternoon and persisting through tonight, with a few gusts to 25 kts especially near the coast where the sea breeze will be active late this afternoon. Seas 2-3 ft this morning increase to 3-5 ft this evening as SW wind wave builds, with 2 ft 9 sec E swell still mixed in.

Monday through Thursday night...A cold front will slide southward into the Carolinas Monday afternoon, turning moderate southwest winds to the north by early Monday evening. The front could be accompanied by scattered strong thunderstorms with gusty winds, mainly between 2 pm and 8 pm Monday. Behind the front, increasing northeast winds will bring Small Craft Advisory conditions Monday night through Tuesday and possibly as late as Tuesday evening as Canadian high pressure builds across the eastern U.S.

The GFS model has backed off its depiction of a coastal trough developing off the GA/SC coast Wednesday. There is still a hint of this feature in the latest GFS and Canadian models, but impacts this far north appear lessened compared to what was shown 24 hours ago. Moderate northeasterly winds Wednesday should veer easterly and diminish Thursday as the center of the surface ridge shifts south across the area.

ILM WATCHES/WARNINGS/ADVISORIES

NC...None. SC...None. MARINE...None.