textproduct: NWS Wilmington

WHAT HAS CHANGED

Aviation discussion updated for the 00Z TAFs.

KEY MESSAGES

1) The next cold front will arrive Sunday night preceded by good coverage of showers and t-storms.

2) Mainly below normal temperatures and dry conditions Monday through mid week.

DISCUSSION

KEY MESSAGE 1: The next cold front will arrive Sunday night preceded by good coverage of showers and t-storms.

Aside from a few sprinkles or light showers across the Pee Dee region through early this evening, largely dry weather is expected overnight into Sunday morning. A pair of shortwaves across Missouri and across east TX will move eastward, eroding the subtropical ridge along the Southeast coast sufficiently to veer mid level winds southwesterly. This should lead to increasing depth of moisture Sunday as a brief 850-700 mb link will exist to the Gulf. Precipitable water values should climb as high as 1.6 inches during the afternoon.

Daytime heating Sunday should help generate 1000 J/kg of SBCAPE with little capping. Scattered showers and thunderstorms will likely develop in broken lines well out ahead of the surface cold front within channels of enhanced upper divergence ahead of the approaching shortwaves. Both GFS and NAM forecast soundings show small helicity values during the afternoon with only 25 knots of 0-6 km bulk shear, implying multicells are the most likely storm mode. Modest boundary layer flow and predicted storm motion do not argue for an overly large wind threat, although gusty winds are possible with any thunderstorm. The I-95 corridor should see the best chance of convection during the afternoon hours, shifting to the coast during the evening. The surface front is expected to move offshore around midnight with cooler and drier air building in late.

KEY MESSAGE 2...Mainly below normal temperatures and dry conditions Monday through mid week.

Much cooler and drier air will move into the region Monday after a cold frontal passage Sunday night which will then get reinforced by another dry cold frontal passage Tuesday. The coldest period looks to be Tue night when the normally colder inland spots could dip into the upper 30s. Fortunately, elevated clouds/wind should help keep temps from falling much more, although it's worth noting the NBM has up to ~15% chance of temps less than 37 degrees, mainly across the normally colder northern areas. Dry air should prevent much risk for frost, although this will have to be watched closely if the forecast trends colder. Temps should start to rebound back above normal later in the week. Looks like the only risk for rain, albeit very minimal, will be near the coast starting Wed night given the greater moisture convergence there.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

VFR to start off the 00Z TAF period. Winds are not expected to decouple tonight, and with decent boundary layer winds fog is not anticipated. Only chance of flight restrictions overnight is a low/moderate chance of low cigs at FLO/LBT, but not confident enough to include mention in the TAFs.

Increasing winds aloft Sunday will mix down to the surface by 14-15z with surface gusts increasing to 25 knots. Prefrontal lines of showers or storms may begin to reach as far east as KLBT and KFLO after 15-16z Sunday, with a moderate to high potential for ceiling and visibility restrictions as the main batch of rain moves through in the late aftn to evening hours.

Extended Forecast...The front should move offshore around 06z Monday with the low levels expected to dry out on northerly winds. Generally VFR conditions are then expected through Thursday.

MARINE

Through Sunday...Bermuda high pressure that has been in place for the past five days will begin to break down late tonight with the approach a cold front from the west. Light southerly winds should veer southwesterly and increase to 10-15 kt Sunday morning, then to 15-20 kt during the afternoon in a combination of an increasing synoptic wind plus local seabreeze effects. Scattered showers and thunderstorms could approach the beaches and coastal waters during the mid to late afternoon hours, but the lion's share of rain may hold off until sunset.

Seas 3-4 feet tonight into Sunday morning will be largely due to 8 second southeast swell. Increasing short period wind waves will build quickly during the day Sunday with combined seas increasing to 4-5 feet during the afternoon.

Sunday night through Wednesday night...A cold front is slated to move through Sun night with some gusts to around 25 kt but likely not enough to warrant a Small Craft Advisory. A better risk for SCA conditions comes starting Tue night after another cold frontal passage with gale gusts even possible along with seas up to around 8- 9 ft.

CLIMATE

After repeated arctic outbreaks in January and February, local year- to-date temperature anomalies on February 10 were as much as 5 degrees below normal. Recent very warm temperatures in March and now continuing into April have erased virtually all of this anomalous cold. YTD temperature anomalies through April 3 are now +0.3 degrees in Wilmington, +0.1 degrees in North Myrtle Beach and Lumberton, but still -0.2 degrees in Florence.

CPC outlooks across the 6-10 day, 8-14 day, and 3-4 week timeframes all show an enhanced potential for above normal temperatures across the Carolinas, implying local cities should have growing positive YTD temperature anomalies by the end of the month.

ILM WATCHES/WARNINGS/ADVISORIES

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