textproduct: NWS Wilmington

WHAT HAS CHANGED

Aviation discussion updated for 12Z TAFs.

KEY MESSAGES

1) Inland portions of the eastern Carolinas should see their longest heat wave of the year so far with five consecutive days of 90 degree heat expected today through Thursday.

2) Rain chances should increase, mainly inland, late this week as a front stalls near the Carolinas.

DISCUSSION

KEY MESSAGE 1...Inland portions of the eastern Carolinas should see their longest heat wave of the year so far with five consecutive days of 90 degree heat expected today through Thursday.

Deep subsidence developing in the vicinity of a 500 mb ridge along the NC coast should lead to sunshine and warming temperatures for the first half of the coming week. 850 mb temperatures should creep up to +17C to +18C at times, at or above the 90th percentile climatological values for this time of year at both the CHS and MHX upper air sites. This should support inland high temperatures near 90 on today, then in the lower 90s Monday through Thursday. This is also largely supported by statistical guidance and multimodel ensemble blends.

So far this year, our longest streak of 90+ degree or hotter heat (four days) occurred April 15-18 at both Florence and Lumberton. This coming heat event should eclipse that duration by one day in both locations. Heat indices could reach as high as the mid 90s Wednesday and Thursday.

With Bermuda high pressure remaining offshore and a light to moderate southerly synoptic wind in place, coastal cities (Georgetown, Myrtle Beach, Southport, and Wilmington) should remain significantly cooler than inland locations. Nearshore ocean water temperatures near 70 degrees should warm by several degrees over the next week, but even then will help provide up to 10 degrees of free, natural cooling to the coast.

KEY MESSAGE 2...Rain chances should increase, mainly inland, late this week as a front stalls near the Carolinas.

After peaking near 5900 meters Monday and Tuesday, 500 mb heights should begin to fall later in the week as the upper level ridge is attacked by a weak cutoff trough over the western Atlantic and a series of stronger shortwaves traversing through the central Appalachians and Northeast. A surface low supported by the first of these shortwaves will move eastward across Quebec on Wednesday, pushing a surface cold front southward into the Carolinas Thursday. The boundary should remain quasi- stationary Friday into Saturday and should lead to scattered to numerous showers and thunderstorms. The latest model runs show the bulk of pcp remaining well inland. The temp difference between the warm land and relatively cooler ocean should produce a decent sea breeze which should help push the chc of pcp farther inland through the afternoon, plus the upper ridge looks like it is trending stronger up along the Southeast coast. Therefore expect bulk of pcp to remain well inland. The coast may also see some shallow moisture and possible showers move onshore at times, but overall QPF looks minimal through at least Saturday.

The NBM may be too optimistic with its high coverage of measurable precipitation (60-80 percent) Friday and Saturday, but this still looks like our best chance for measurable precipitation since the thunderstorms we had last Monday. Severe drought continues across portions of the Carolinas and six-month rainfall has only been 50 to 70 percent normal, almost ten inches below normal at Myrtle Beach.

AVIATION /09Z SUNDAY THROUGH THURSDAY/

VFR continues. Sea breeze will kick off some midday/afternoon clouds, but ceilings will be above 3k ft and dry air aloft will keep cloud depth limited. Enhanced south to southeast winds with the sea breeze, strongest for immediate coastal sites, eventually reaching FLO/LBT late in the day but with lesser speeds. Potential for some patchy MVFR fog around daybreak Mon, especially for coastal locations.

Extended Forecast...VFR dominates through Wednesday although morning fog potential will increase through midweek. Restrictions with isolated showers and storms possible late Thursday.

MARINE

Through tonight...Bermuda High will maintain southerly flow across the waters today and tonight. Inland heating will enhance winds near shore in the afternoon which could lead to gusts around 15kt, but generally speeds will be 10 kt or less across the waters. Seas 2-3 ft will be a mix of a southerly wind wave and a southeast swell.

Monday through Thursday...Bermuda high pressure will remain over the western Atlantic through the period with generally light southerly winds expected. Seabreeze enhancement nearshore could locally increase nearshore wind speeds to around 15 knots from mid afternoon through early evening each day. Seas will remain in the 2 to 4 ft range through most of the week. May see the gradient tighten a bit with front reaching into the Carolinas Wed night into Thurs leading to a slight bump up of winds and seas, but overall sub-SCA conditions through the week.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Coastal Flood Advisory from 9 PM this evening to 1 AM EDT Monday for NCZ107. SC...Coastal Flood Advisory from 7 PM to 11 PM EDT this evening for SCZ054-056. MARINE...None.